NOVEMBER 1990 II ECHNOLOGY - VIDEO - STEREO - COMPUTERS - SERVICE L'-*--'^.i. ¥^.:^^ Vi' I \i~. ^?^'.J^ f^cJ-CviL.' :^^W-. BUILD A SOLID-STATE LASER! "V Our handheld laser runs on DattenesT WHAT'S THE FUTURE OF SATELLITE TV? A tuuA at how the latest direct-broadcast proposals are aimed at cable TV : • SCREEN YOUR TELEPHONE CALLS ELECTRONICALLY! 3y buildinq our call screener BUILO A PORTABLE QUAD ANTENNA A nign-perrui'mdiiuti antenna for the 2-meter band SPICE UP YOUR DESIGNS _„ G£RHSBACK f-uBi-lCATiOH FLUKE AND PHILIPS - THE GLOBAL ALLIANCE IN TEST & MEASUREMENT FLUK FLUKE 73 in- VobDlirKnA xonat 200Q+ twut iHtlirylle 3yB»wnny 'Suflfl B ttO U^. lit pflcs FLUKE 75 SIS' FLUKE n SIM* hakgragtH ils!>lty Volts. iy«B,1Wi mAIballiKBafk CIMglsl OiWtaiicilc 2(m+ tnur MUnrtft omtBSEdc huMtoinllauly Aunnfmngetvikf 3000+ hot* btfiryilg MAxmosthMa lyeawmitt PHILIPS More than two million users agree: the Fluke 70 Series handheld digital multimeters are simply the best. These originals have become classics. And the reasons are simple. They are accurate and easy to use. Features made popular by the 70 Series-like fast autoranging, continuity beeper, and quick diode test— are now standards in Sie industry. Other 70 Series features stand alone. Touch Hold®, for example, locks the reading on the display and signals you with a beep. So you can keep your eyes on the circuit and probes. The 70 Series are built without compromise. All current ranges are fully fused. The reastance function is overload protected to 500V. No detail has been overlooked in making these rugged and reliable meters the first choice of two million professionals. IVIade In the USA using state-of-the-art man- ufacturing methods, every Ruke 70 Series multimeter is backed by a 3-year warranty. Another first in the industry. Choosing the best handheld multimeter is very simple. Pick up the Fluke 70 Series at your Fluke distributor today. Or call 1-800-44-FUIKE, ext 33, for a free brochure. John Fhike Mi(j, Co., Ire, P.O, BmaiSO. Evefell.WA 98206. J.S.: (206) i56-5«tl CansOi (416) 9W7600 CWio counWes: (206) 356-5500. © 1990 John RukB Mlg. (k)., Inc. M (Igl^ mscfved. Ad,no.0701F7tl FROM THE WORLD LEADER IN DIGITAL MULTIMETERS. FLUKI CIRCLE 121 ON FREE INFORMATION CARD November 1990 aecinjiiSEs 34 SEMICOfSIDUCTOR LASER SYSTEM Visible-light laser diodes are at the heart of this handheld, rechargeable, semiconductor laser system. Robert lannini 41 PORTABLE 146-MHz QUAD ANTENNA Build your own 2-meter quad antenna. Linton G. Robertson, KJ2EF 49 PHONE-CALL SCREENING SYSTEM Build our system that puts an end to junk calls. John C. Koller 58 THE CHANGING FACE OF SATELLITE TV A look at how small, flat antennas could boost the popularity of satellite TV. Robert Angus Emsm 63 SPICE Can a PC-based circuit-simulation program take the place of breadboards? TJ Byers 86 COMPUTER CONNECTIONS SCSI/ESDI shootout, and a pair from Micropolis. Jeff Holtzman ■''^J'''^^-'-N.'y^- 6 VIDEO NEWS What's new in this fast- changing field. David Lachenbruch 24 EQUIPMENT REPORTS Coordinated Time Link CTS-10 Computer Time Standard 69 HARDWARE HACKER A look at walking-ring counters, electronic dive, vortex coolers, and more! Don Lancaster 83 DRAWING BOARD Some final words on video, then on with our controller! Robert Grassblatt 81 IC SPOTLIGHT A new column debuts this month! Mike Mullin 85 AUDIO UPDATE What audio test reports do— and don't — tell you. Larry Klein Vol.61 No. 11 r I* = SI iJl.ti'tti '~\i — '■ HI iCJJk.'m ■ 1 .lilK ■S ^I'tU^SiiSi^^i i.vix '^^t: ^ ^^^£^£^ *^!E^^5t^ ' PAGE 63 PAGE 41 106 Advertising and Sales Offices 106 Advertising Index 14 Ask R-E 97 Free Information Card 16 Letters 105 Market Center 32 New Lit 26 New Products 4 What's News g w m 13 ON THE COVER o o IT h- O LU _1 UJ o < £ ■Kailm -^ _.„ mt^ggiu:s ■UHA ASQUD-^wrm uima Htiura iHc ruTURi; DF unum Tvi A »il In the past 25 years, tasers have become an integral part of both the technological world and our every- day lives. Yet, because of fragile glass laser tubes and high-voltage power requirements, there ahve been limits to their applications, es- pecially for hobbyists. Now, a series of laser diodes recently developed by Toshiba, which emit visible light and which don't require a high-volt- age powersupply, just mightopen up a whole new world of applications. We put the new visible-light laser diodes to work in handheld, battery- powered, rechargeable, semicon- ductor laser system. To find out how it works, and how to build your own, turn to page 34. THE DECEMBER ISSUE GOES ON SALE NOVEMBER 1. BUILD A MACINTOSH Use an Apple motherboard to build your own Macintosh computer — for a fraction of what Apple charges, HIGH-TECH CHRISTMAS TREE Just in time for the holidays, this unique and attractive project teaches some valuable lessons about frequency-selective filters. HOW TO CHOOSE THE RIGHT PROBE FOR YOUR TESTING PROBLEM Save time and money by picking the right probe for the job. SUZIE -A look at computer-aided logic simulation for testing and verifying yourdesigns. A£ St service to readers, RADIO -ELECTRONICS publishes available plans or inforrnaUon relating to newsworthy products. techneqLes and sci«ntiftc and technological develcpm^nts. Because Qi possible variances in the quality and condition of materials and workmansliip used by readers, RADlO-ELECTRONiCS disclaims any responsibility lor the safe und proper functioning of reader- bu I ft projects based upon or from plans or information published in tliis magazine. Since Some of the equipment and circuitry described in RADEO- ELECTRONICS may relate to or be covered by U.S. patentSn RAD 10 -ELECTRONICS disclaims any liability for tho infringement of such petents by the making, using, or selling of any such equipment or circuitry, and suggests that anyone interested in such projects consult a patent attorney. RADIO ELECTRONICS, (ISSN 0033'7BS2] November 1990. Published monthly by Gemsback Publications. Inc., SOO-B Bi County 6-ouievard. Farmingdale, NV 11735 Second-CUss Postage paid at FarmingdAie. NV and additional mailing offices, Second-Oass mail registration No. 9242 authorized at Ton:}nto, Canada. One-year subscription rate U.S.A. and possessions $17.97, Canada S23^.97. all other countries S^^-^V, AlE subscription orders payable in U.S.A. funds only, via international postal money order or check drawn on a U.S.A. banh.SinglecopiesS^.SO.-^ 1990 by Gemsback Publicatiunsjncr All rights reserved, Printed in U.S.A. POSTMASTER: Please send addrvss changes to RAOIO-ELECTF^ONICS. Subscription Dept.^ Box 55115. BoutdBr CO 80321-51 15. Astamped self-addressed envelope must accompany all submitted manuscripts and/or arbvork or photographs IT thsir return j« deSFrea should they be rejected. We disclaim any responsibility for the loss or damage of manuscripts and/or artwork Or photographs while in our possession or otherwisCr Hugo GvnKbackWM-iSSiy founder M. Hiir^fly G«msback, ' «dltor-in-ch^ef, einBritd^ Urry Steciilsr, EHF, CET, cKJitor-in-chiet and publishar EDITORIAL DEPARTMENT Brian C, Fenton. editor Marc Spiw^k, associate editor DantQl Gi>odmaFit technical editor Kim Dunleavy. assistant technical edltjor Teri Sc^duto. assistant editcr Jeffrey K. Holtzman computer editor Robert Gross blatt, circuits adltor Larry Klein, audio editor David Lachenbruch contributing editof Don Lancaster cfjntrjbuting editor Richard D. Fitch contributing editor Kathy Terenzi, editorial assistant ART DEPARTMENT Andre Ouzant, art director Injas Loe, illustrator Russoll C Truetson. Itlustrator PRODUCTION DEPARTMENT Ruby M. Yee, praduction director Janice Boi:., editorial production Karen S, Tucker advertising production Marcella Amoroso production assistant CIRCULATION DEPARTMENT Jacqueline P. Cheesaboro circulation dirsctor Wendy Alanico circulation analyst Theresa Lombardo circulation assistant Michele Torrillo, reprint bookstore Typography by Mates Graphics Cover photo by Diversified Photo Services Radio-Electronics is indexed in Applied Science & Technology Index and Readers Guide to Periodical Litef- eture. Microfilm & Microfiche editions are available. Contact circulation depart- ment for details. Advertising Sales Offices listed on page 106. m. ^ The Auriil Bureau Ot Ciftxilalior WITH CIE, THE WORLD OF ELECTRONICS CAN BE YOUR WORLD, TOO. Look at the world as it was 20 years ago and as it is today. Now, try to name another field thai's-grown faster in those 20 yeare- than electronics. Everywhere you look, you'll find electronics in action. In industry, aerospace, business, medicine, science, government, communications — you name it. And as high technology grow^, electronics will grow. Which means few other fields, if any, offer more career opportunities, more job security, more room for advancement — if you hove the right skills. SPECIALISTS NEED SPECIAUZED TRAINING. I! stands to reason thai you learn anything best from a specialist, and CIE is the largest independent home study school specializing exclusively in electronics, with a record that speaks for itself, According to a recent survey, 92% of CIE graduates are employed in electronics or a closely related field. When you're investing your time and money, you deserve results like that. INDEPENDENT STUDY BACKED BY PERSONAL ATTENTION, We believe in independent study because it puts you in a classroom of one. So you can study where and when you want. At your pace, not somebody else's. And v/ith over 50 years of experience, we've developed proven programs to give you the support such study demands. Programs that give you the theory you need backed v/ith practical experience using some of the mcst sophisticated electronics tools available anywhere, including our Microprocessor Training Laboratory vrith 4K of random access memory, Of course, if you ever have a question or problem, our instructors are only a phone call away. START WHERE YOU WANT, GO AS FAR AS YOU WANT. ClE's broad range oi entry. intermediate, and advanced level courses in a variety of career areas gives you many options. Start with the Career Course that best suits your talents and interests and go as tar as you want — all the way, if you wish, to your Associate in Applied Science Degree in Electronics Engineering Technology. But wherever you start, the time to start is now. Simply use the coupon below to send for your FREE CIE catalog and complete package oJ career information. Or phone us, toll-free, at 1-800-321-2155 (in Ohio, 1 -800-523-9 1 09). Don't wait, ask for your tree catalog now. After all, there's a whole world of electronics out there waiting for you. CIE Clflveiand Institute of Electronics, Inc, 177B Ease 17th Streac, CteveJand, Dh.o 4^114 Memberwise Accredited MeniLbei NatiDnol Home Study Council Cleweland Institute of Electronics, Inc. 177B East lyth Screec. Clevaland, dhio 44114 ABE179 M EScaa I want to team from the specialists in electronics— -CIE. Please send me my FREE CIE school catalog, including details about CIE's Associate Degree program, plus my FREE package of home study information Name (print): Address; City:. Age: State: Zip:. Area Code/Phone No,: /_ Check box for G.I, Bill bulletin on educational benefits: MAIL D Veteran D Active Duty TODAY! i!f;V#-i;)W A review of the latest happenings in electronics. Non-poliuting electrical power With alternative methods of gen- erating electricity being explored around the world to counter the growing problems of atmospheric pollution and power outages due to natural disasters, researchers at Bellcore (Livingston, NJ), have de- veloped a non-polluting process that might lead to smaller, lighter, more reliable, and less costly power sources. "Fuel cell" systems de- signed using the new method could be used in a wide range of applica- tions, including replacing tradi- tional rechargeable batteries as emergency backup power sources for many applications. In small, experimental prototypes ofthe fuel cell, Bellcore has convert- ed gas to electricity using a thinner- than-paper material sandwiched be- tween two conducting metal films. Electricity is generated when hydro- gen or other fuel gases are "blown" over the fuel cell's surface in the presence of oxygen or air. Accord- ing to Christopher Dyer, who dis- covered the method while explor- ing new ways to improve communi- cations power systems, no pollu- tants are created in this process, since the hydrogen is simply con- verted to water vapor. While NASA has used fuel cells in spacecraft, commercialization has been slow due to high production costs of existing designs that require separated gas intakes of pure gases. Bellcore's prototype operates in a gas mixture. Essentially, its materials "separate" the gases internally, greatly simplifying the engineering. Because those materials are so thin, practical devices could be made by depositing the materials on both sides of an inexpensive, continu- ously moving roll of plastic. Pre- determined lengths of the pro- cessed material could then be rolled into an open spiral, through which air together with the fuel gas would be passed to give the required power. The prototype's extremely good power-to-weight ratio — more than 50 watts of electrical power per pound of weight — means that po- tential commercial devices could be small as well as lightweight. The pro- totype generates quiet, clean power and has no moving parts, suggest- ing that future devices could pro- vide users with a reliable, long-lived power source. The next step is to upgrade power levels while retaining the attractive weight and volume, which might be accomplished by improving gas effi- ciency so that heat removal equip- ment won't be needed or, perhaps, using the heat as a benefit. Some possible future applications of de- vices are emergency power supplies for remote telephone terminals, re- fillable power supplies for portable phones, integrated-circuit power sources, home generators running off natural gas, power sources for portable computers, and power plants for electric vehicles. Record-breaking electrical lead An electrical lead — developed in a joint effort between Westinghouse Electric Corporations Science & Technology Center and the Super- conductivity Pilot Center at the U.S. mut.^,' (^ iHfer .id^^^H m "T te 1 BPufr' ^^^H^ : WESTINGHOUSE TECHNICIANS Don Martin and Ray Malingowski make con- nections for a test run ot the complete assembly of the electrical lead that set a world record for current carried by a prac- tical, high-temperature superconductor. Department of Energy's Argonne Na- tional Laboratory — was used to set a world record for current (2,000 am- peres) carried by a practical high- temperature superconductor This high-current lead could become one of the first devices using supercon- ducting materials to come into wide- spread commercial use. It was designed to connect room-tempera- ture power supplies to liquid-helium- cooled low- temperature supercon- ducting power equipment, and has the potential to greatly reduce helium refrigeration costs in applications such as magnetic resonance imag- ing, superconducting magnetic ener- gy storage, or the superconducting supercollider. Ten-year battery Scientists at Sandia National Lab- oratories (Albuquerque, NM) have developed a battery for military and space applications that can provide power for 10 years. That longevity was achieved by making a number of modifications to existing lithium-sul- fur dioxide batteries, which are pri- marily used by the armed forces for applications requiring long life and high energy density, and which expe- rience failure most frequently occurs due to glass corrosion. The major change made involved the use of a specially developed glass, CABAL 12, that eliminates cor- rosion in the glass-to-meta! seal. Other modifications included using molybdenum as the positive terminal to inhibit corrosion by products of electrolysis, placing a nickel grid in the lithium anode for increased effi- ciency, and using an improved meth- od of attaching the cathode tab to the positive terminal. In addition, by fully annealing the case and increasing the radius of curvature at the bottom of the can. stress was reduced, which eliminated cracking in the steel cell case. The ten-year lifespan was pre- dicted based on studies evaluating the performance, reliability, and aging characteristics of battery cells over a period of years. 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Jasik • 1,408 pages, 946 illustrations • covers all types of antennas currently in use with a separate chapter devoted to each • provides detailed data on physical hindanientals, operating principles, design techniques, and performance data • up-to-the-minute information on antenna apphcations • a must for those involved in any phase of antenna engineering Publisher's Price $94.50 MAGNETIC RECORDING HANDBOOK Technology and Applications Edited by CD. Mee and ED. Daniel • 1,100 p^es, 400 illustrations • the most comprehensive reference available on alj aspects of m^netic recording technology • features contributions from 25 international experts • includes coverage of error correction coding and magneto-optical recording IMagnetic il Recordin i Handbool AM'' 412I74X 0471774 Publisher's Price $86.95 AUDIO ENGINEERING HANDBOOK Edited by K.B. Benson • 1,056 pages, 722 illustrations • the ideal on-the-job reference for all designers, operators, and servicers of professional and consumer audio equipment • a one-volume source of fundamentals and how-to information encompassing all aspects of audio engineering • coverage includes DSR CDs, DAT, and noise reduction developments • contributors include Ray Dolby, R.C. Cabot, and many more for only $14.95— when you join the ENGINEERS' BOOK CLUB^- Publisher's Price $94.95 MODERN ELECTRONIC CIRCUITS REFERENCE MANUAL ByJ.T. Markus • 1,264 pages, 3,666 circuit diagrams • a haticly, desktop reference with 103 chapters organized by "family" grouping • filled with predesigned and use-tested circuits to save you production time and money • includes concise summaries of all the recent applications notes, journal articles, and reports on each circuit, efficiently organii:ed and indexed for the practicing engineer 4041461 Publisher's Price $8995 ELECTRONICS ENGINEERS' HANDBOOK, Third Edition Edited by D. G, Fitik and D. Christiansen • 2,496 pages, 1,600 illustrations • the definitive reference to electronics engineering • fully updated to cowr all recent advances and developments • rang^ from essential principles and data to the latest design solutions and practical applications — with an all-new chapter on standards • written and compiled by more dian 170 contributors — all experts in their fields 09/820 4 reasons to join today! 1. 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If, because of laie delivery of the Bulletin you receive a Main Selection you do not want, you may return it for credit at the Club's expense. As a Club member you agree only to the purchase of two additional bopks during your first year of memhership Membership may be discontinued by either you or die Club at any time after you have purchased the two additional books. McGraw-Hill Book Clubs Electfonics and Control Engineer^ Book Club® P.a Box 582 Hightstown, Pg 08520-9959 Please enroll me as a member of die lUearonics and Conirol Engineers' Book Club* and send me die book 1 have chosen for only $14-95 plus locaJ tax, postage and handling. 1 agree to purchase a minimum of two addi- tional books during my first year as outlined under die Club pLui described in this ad. Membership in the dub is cancellable by me or McGraw-Kd] any time after die two Imok purchase requirement has been hdfiiled. A shipping and handling charge ii added to ail shipments. 1 nisb to order die foliotting book; D .ANTENNA laiCLNEERING HANDBOOK 022/910) n MODEtlN EU-aRONIC QRCUITS MKRENCR NUNU.AL (404/461) D Eli':CTRONlCS ENGINEKRS' HANDBOOK, Ve (209/820) D ALDIO ENGIN'EKRING HANDBOOK (047/774) D MAGNimC RECORDING HANDBOOK (412/74X) Si^aiuit- Nume_ Addn^^'Apl. #_ Cit)'/Sai(vlip nilsonjtr^blectto accqit^ce b>' McGraw-Uitl. offer good only to nrA' mnnbien. Fd^^]^ iflcnit»?r acccpLan» subject 10 t^Kisl condiElon^ ECGA-042 § m rri J3 o 11 |in< I Phase Shift Circuit * using built-in oscllloscopt introd^fL'^Vn-'" Hiding Easy to use, menu-driven, mouse controlled circuits come alive on your terminal! I DC Series Circuits Ohms's Law • Kirchhoff s Voltage Law I Temperature Effects Voltage sources • Resistances in series I Voltage Dividers Internal source resistance Voltage regulation I DC Parallel Circuits Networks • Current dividers I DC Series-Parallel Circuits DC Circuit analysis by reduction I DC Circuit Analysis Mesh circuit and branch current analysis I Supeiposition Theory Circuit analysis using superposition I Bridge Circuits Delta - Wye conversions I Ptiasor Mattiematics Phasor theory I Series AC Circuits RC, RL and RLC circuits Power and power factors I Resonance Tuned series circuits Parallel resonance I Parallel Resonance Tank circuits I Polyphase Systems Power in polyphase systems V p« f uter build and comP siiTiula*®^ , onics elecfc circuits- labo ratory New PROTOLAB™, a state of the art electronics lab for the hobbyist's, student's or engineer's pc. Now, you can build and experiment with actual circuits, choosing from an unlimited numt^er of components, including resistors, capacitors, inductors, general impedence, AC voltage sources, batteries, AC/DC current sources. Then, analyze your circuits with built-in high tech instruments — voltmeter, ammeter, ohmmeter, oscilloscope, wattmeter, sweep generator, breadboard, temperature adjustment and frequency control. This complete electronics lab, simulates thousands of dollars worth of parts and instruments ... all built-in with easy to use, menu driven, mouse controlled PROTOWARE™ software. Plus, you get a unique experiment trook, featuring over 75 experi- ments and circuits. Enjoy countless hours of fun, while learning. And, you won't blow up your "lab", |}ecause it's fool proof and safe on your pc. Here are some typical circuits you can build and test. Resistor Series/Parallel Circuit demonstrates current division in a parallel circuit Thevenin Equivalent Circuit calculating voltage drop and curren! tiow using built-in ammeler/vollmeter PROTOLAB provides a complete lab station of tiigh tech equipment including... ■Pw^i^B^W^ B^^r^^B^nBcl^^^B Via IBhh • 1 = ^^^B\'^^^H #< 10 2 VIMT til YOLTS? Parallel Resonance LC Tank Circuit using sweep generator to vary voltage across tank, moniloring circutt response Voltmeter Frequency Generator Frequency Compensated Bridge using osciltoscope to measure AC signal offset by DC voltage Order today... start building s and testing ^^^ s circuits today... s s ^s Complete, for IBM/compatibles* . . .ONLY *99®^ For Macintosh with high resolution, enhanced graphics".,.*! 29^^ 'IBM/compatibles require 384K RAM, CQA [640x200] video cUsplay and mouse "Madntcsh requires Macintosh 51 2E, MAC XL, MAC PLUS. MAC SE. MAC II Includes lab experiment tiook and exclusive PROTOWARE - Call toll-free for details GLOBAL 1-800-572-1028 SPECIALTIES Global Specialties. 70 Fulton Ten^ace. New Haven, CT 06512. Telephone: [203) 624-3103. ».? tnterplex Electronics. 1990. Ali Global SpeciaHies breadboarding products made in USA CIRCLE 185 ON FREE INFORMATION CARD I'f. -l- to o z o tr \3 UJ _i UJ O Q < a: SPLIT BATTERY I'm building a circuit using op-amps that require a split supply. TKe final product is go- ing to be powered by batteries so I've been using resistors to create a split supply from a nine vott battery. It works but I've noticed that the perfor- mance of the op-amps is much better if the circuit runs of a real split supply. Is there some simple circuit I can use to get a real negative voltage from a single battery? — J. Laberdie, Somerville, NJ This is a problem that you run across whenever you use op-amps like a 741. They're easy to use, cheap, and available everywhere, but running them off batteries is a pain in the neck. There are tw^o ways you can take care of the problem. The first one is simply to use two nine-volt batteries connected in series and take your ground from the center point. The only possible problem with this ap- proach is that there may not be room for the second battery in the en- closure you're going to use. If the only components that use the nega- tive supply are the op-amps, then the battery that's supplying the negative voltage will last for a very long time since the draw from the op-amps is very low. If you insist on doing the job elec- tronically, you can use the circuit shown in Fig, 1. The 555 is set up as an oscillator with a duty cycle pretty close to 50% , The components at the output work as a voltage-doubling rectifier On the positive half cycle of the output wave. D1 is forward biased and CI charges up with respect to ground. On the negative half cycle, Cl discharges through D1 and charges 02. Since D2 is reverse bi- ased, 02 can't discharge through 01 . The result is that we have a voltage at the cathode of D2 that's negative with respect to system ground and the voltage is renewed with every full cycle of the 555 output. The 555 can supply about 200 milli- amps but all you can really get from the circuit is less than half that amount. Since you're only using the negative voltage to supply the op- amps, you've got more than enough current available to do the job. The negative voltage you'll get will be a few volts below the positive voltage supplying the 555, but the exact number depends on the amount of current you're going to draw from the circuit. XT UPGRADE I have an XT clone and am thinking of upgrading to an AT. The only thing that's prevent- ing me from doing so is that, while I don't mind spending the money for the mother- board, I resent having to lay out money for a new I/O card, disk controller, and so on. I want to know whether or not I have any alternatives? — J. Bendel, Bogota, NJ The difference in performance be- tween an 8088-based XT and a 286 AT is what is referred to in the tech- nical journals as "mind blowing," A consen/ative estimate would be that you'll see at least a five-fold increase in processing speed. Ifyou want to keep the costs as low as possible, the onlything you'll really have to add to the motherboard is faster memory — and even that's not for sure. There's no reason what- soever why you can't use the cards FIG. 1— THIS SIMPLE CIRCUIT can pro- vide you with a negative voltage from a positive supply. you have in your XT in an AT, You won't be getting the best perfor- mance possible out of the new moth- erboard, but that's a long way from saying that it won't work at all. The sixteen-bit cards made for the AT are faster than the eight-bit cards you're using in the XT but, when you actually compare things, the performance dif- ference isn't anything like the dif- ference you'll get by swapping the motherboards. The only thing to be careful of is how you set up the AT since you have an XT-controller card. The AT stores in memory the kinds of drives you have, and needs that information to operate because it has drive tables built into the ROM, The XT doesn't have any of those and has to depend on drive tables stored in a ROM on the hard-drive controller card. The way around that is to tell the setup program that you don't have any hard drives installed. Memory speed is a different prob- lem. Most AT boards can run at two speeds. The low speed is usually about 8 MHz and the high speed can be anything up to 20 MHz. If the memory you have in your XT is rated at 12 nanosecondsorless. the ATwill probably crash at high speed. Your alternative is to either run at low speed or replace the memory with 1 0- nanosecond RAM, The price of memory changes every day but is usually somewhere around a hundred dollars a megabyte. Since the difference between the low and high speeds of the AT is pretty noticeable, you should really consid- er getting whatever memory is needed to have the motherboard run as fast as possible. WASHING BOARDS Some time ago you ran a se- ries on how to make printed circuit boards and. in general, I've been successful following your advice. The only place I have any trouble is in develop- ing the board. When I wash the developed board with water, the board often doesn't clear. 14 If I put it back in the developer for a longer period, all of the resist gets dissolved. What am I doing wrong? — G. Fischer, New York, NY Making printed circuit boards at home is time-consuming enough, without having to seek out how-to information, as well. There are lots of books on the subject, and several companies make the supplies, but the information you get from them is often more theoretical than practical. There are so many variables in- volved in producing a good board that it's almost impossible to pinpoint your problem. Mistakes that are made in pouring the resist may not be evident until you actually dunk the board in the etchant, and there's no easy way to know exactly where the mistake was made. Since you indicated in your letter that you've had some suc- cess in making boards, we can elimi- nate a few of the steps as the source of your problems. The light source you're using and the exposure time are probably cor- rect since a mistake here means that it would be impossible to have any success at all. The same sort of argu- ment applies for the quality of the printing negatives. My best guess would be that you're either not coat- ing the copper blank properly or you're making a mistake when you develop the board. When you pour the resist on the board, you want to keep the actual coating as thin as possible. The best way to do that is to pour the resist on one edge of the board and then tilt the board one way and then the other to let the liquid resist flow across the entire surface. If you have a problem with this, you can use a small brush to help the resist flow around the board. Once the board is covered, let it rest at a sharp angle on a piece of paper towel so the excess resist can flow off the board. If you let the safe light hit the board at the right angle, you'll be able to see the excess resist flowing to the bottom of the board. Keep on blotting the edge until all of the excess is off the board. You can air dry the resist but that takes overnight. A better way is to use a hair dryer on a medium setting. That will dry the board in a few min- utes but the resist can be ruined if you let it get much over 1 25°. Developing the board is a pretty straightforward operation. Put the board in the developer and gently rock the tray back and forth for about 30 seconds or so. That's enough time for the first dunk. Wash off all the dissolved resist before you give the board more time in the developer. One piece of information you won't see anywhere but in Radio-Elec- tronics has to do with washing the board in water Fill a tray with COLD WATER (about 70 degrees Fahren- heit is fine), and dunk the board in and out of the water If you use hot water the dissolved resist won't wash off the board. Once you see the board clear (the foil pattern will start to show and the rest of the copper will be clean look- ing), take the board out of the water and shake the excess water off it. Don't wipe it because the resist is still very soft. Repeat the developing step and then wash it again. The pattern should appear clearly on the board and, once it dries, you should have no trouble etching it. R-E If only your broken VCR, Computer or TV... could talk. Finally, one book with all the informarion you need for fest repair jobs. 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CA customers add 6.25% tax _ Total _ F(^ credit cards, call toll-tree 800'B54-7179 Company: t^Iame: Title: Address: Cily: Dept.: _ State:. -Zip:_ Phone: ( Signature:- tRequired tor all orders v/ilhout purchase order.) reio Z m 03 m O 15 EARN YOUR B.S.E.E. DEGREE THROUGH HOME STUDY Our New and Highly Efteclive Advanced-Place- ment Program for e?(perienced Electronic Tecli nicians grants credrt for prevbus Sch-ooling and Professional Experience, and can greatly re- duce the time requHTed to comptel© Program and reach graduation. No residence schooling re- quired for qualified Electronic Technicians. Through Ihis Special Program you can pul] all of ttie loose ends of your electronics background together and earn your B.S.E.E. Degree. Up- grade your status and pay to the Engineering Level. Advance Rapidly! Many finisti in 12 months or less. Students and graduates In sll 50 States and throughout the World. Established Over 40 Years I Write for free Descriptive Lit- erature. COOK'S INSTITUTE OF ELECTRONICS ENGINEERING ^IJ 4251 CVPRESS DRIVE JACKSON, Mississippi 3921 2 CIRCLE 58 ON FREE INFORMATION CARD ssiSt^k TpP^ LETTERS Write to Letters, Radio-Electronics, 500-B Bi-County Blvd., Farmingdale, NY 11735 HOW TO FIND SCHEMATICS Trying to locate information through manufacturers who have moved or gone out of business is a difficult task. One method that's worked for me is to send a short request for information on file for the patent number of the equipment, plus $0.50, to the Commissioner of Pat- ents, U.S. Patent Office, Wash- ington, DC 20231 . Within six to eight weeks, you will receive a letter stat- ing the additional fee needed to cover printing and shipping costs of the ma- terial or the information used to pat- ent the equipment. (The original $0.50 is applied toward the cost, and can be refunded if you don't want to pay the fee to receive the informa- tion.) 1 sent for the patent information on an instrument amplifier and re- ceived schematics with detailed the- ory of operation. Take advantage of a little-known public sen/ice! DARRELL W. OVERFELT Kansas City. KS ACCURATE OSCILLOSCOPE MEASUREMENTS People who use digital-storage scopes based on sampling tech- niques speak of "bandwidth limiting." Dave Sweeney's letter in the August issue of Radio-Eiectrontcs stated the bandwidth needs to satisfy the Nyquist criterion, which, for faithful reproduction, requires a sampling rate at twice the highest frequency component in the signal. By definition, a scope's bandwidth is assumed to be the —3-dB frequen- cy response point of the scope's ver- tical system. When making accurate measurements, we should be con- cerned that the system bandwidth is adequate — that means right from the probe tip. Just as the bandwidth of a pulse is approximately the reciprocal of its length, the bandwidth of a com- ponent is approximately the re- ciprocal of its rise time. And. similarly, the bandwidth of a scope using a combination of components with known rise times approximately equals the reciprocal of the RMS val- ue of their reciprocals. Many scope users fail to re- member that the —3-dB point is a power response, while the observed signal is in terms of voltage that equates to -6 dB. for the so-called Gaussian response. In actual fact, most low-cost scopes use a peaked response to obtain the rated band- width and are non-Gaussian. Any scope, regardless of cost, exhibits 30% error at rated bandwidth. Again, by definition, the vertical amplifier re- sponse is down to 0.707 in amplitude at the -3-dB power response point. If you want to make accurate mea- surements with a scope, use one that has a bandwidth 3 to 5 x that of the highest-frequency component in the input signal. Similarly in non-Gaus- sian-response amplifiers, strange phase shifts sometimes occur that can distort the viewed signal, par- ticularly as rated bandwidth is ap- proached. Think about how many measurements can be tolerated with an uncertainty of 30%. RALPH CAMERON Government Accounts Manager Tektronix Canada Inc. HINDERING THE HANDICAPPED As totally blind individuals, my wife and 1 are becoming quite frustrated with the consumer-electronics indus- try. In an age when LSI and other fabrication techniques could give us greater access to new and useful consumer electronics, we are en- countering more and more barriers to our operation of many units. Those are the ones that contain visual-only functions or printed "keyboards" on perfectly smooth panels, which make operation without sight very difficult or impossible. For nearly ten years, we enjoyed absolutely reliable operation of a dual-alarm GE clock radio, which cost about $80 and had direct numeric keyboard entry of times and frequen- cies by a keypad much like that on a push-button phone. When the key- board became erratic, we found that the radio could not be replaced be- cause parts were no longer available. All the new clock radios seem to CIRCLE 108 ON FREE INFORMATION CARD use what I disparagingly call the "idiot data entry" method, by which you hold a key or press a spot until the desired number appears on display — a system totally unusable without sighted assistance. If data entry on clock radios — and some other elec- tronic products, for that matter — was similar to data entry on scanners and push-button phones, a few quick key- strokes would provide absolutely re- liable operation for the blind and sighted alike. Computerized home-appliance controllers could be very helpful to us. if we could program them reliably without sighted assistance. (Many of us do not have sighted assistance easily available.) While some of our needs are best met by special devices made for the blind, those are very expensive be- cause they are made for such a small market. However we could use many off-the-shelf items if their manufac- turers would consider the possible sightless operation of those prod- ucts. I sometimes think it would be interesting if those who design con- sumer electronics could be rendered totally blind for several hours, during which they would have to attempt op- eration of their equipment, I believe it is time for the electronics industry to examine ways in which it might pro- vide greater accessibility to its prod- ucts by the blind. Do you know of any company that produces a good clock radio to meet our needs? DAVID PLUMLEE Independence. MO We'll be presenting sonne projects that you should find useful in upcom- ing issues, including an E-Z Tune FM radio. However it sounds as if your clock radio 's keypad may simply need a good cleaning. You might want to try using TV-tuner cleaner on the switch contacts. — Editor AC POWER AND MICROWAVES I'm writing about two articles in the August issue of Radio-Elec- tronics. First, I found the article on AC-power measurement to be well written and very informative. I would like to see more of such articles. There is one method of measuring power that is missing. That is using four-quadrant multipliers, such as one using RCA's transconductance op- amp, CA3060. I have assembled the parts for a wattmeter based on the CA3060 and have a prototype sche- matic, but have not gone further yet. Figure 14 in the article, using the pulse-width modulator method, inter- ests me, and I will investigate it fur- then One note, though: The analog switch in Fig. 14 is drawn incorrectly so that the integrator sees the nor- mal, but never the inverted input. The second article is the one on microwave technology by Joe Cam In the history of microwaves he gives an erroneous view of the use of vacuum tubes and omits an important applica- tion. He says. "By World War II, oper- ation at 200 MHz was possible, 500-800 MHz was achieved by the end of the war, and 800 MHz by the early 19503, " In truth, by the late 1940's we had tnode vacuum tubes that would work up to about 5000 MHz. In 1949, I worked on path-loss measurements for proposed relay sites for bringing AT&T's TD-2 micro- wave-relay system into Denver The TD-2 band is 37 to 4200 MHz. That system had already been built some distance west of New York. The fol- continued on page 25 Model LrT<:^3tH>o 260IIIH ^lUA LltHlM.''A Function RaLio'jTiCE'n'JiL Rrcquency FrEquen[:>' Frcqianc.v RaiiEe 10H£- ■i4GHi lOMHa- IMHa- DEaplity lU Dif[iL w/KunrEinn AntiunnntiirF Hi Di|;tl JhCP 8l>ljflE LEll t>:ij KF Signal Stronglh Indicator IC Segment AeijiJ.s.t.ihk- B.'irjjrnph ' * Price S375.. $11^. $239. SITS. ^ !^ ntii ti^'i Lv: pmuJ(ISS0. -U'DM«ik-K Nk;icls & ACfHuwr ncjapt^r infSuded. fjirrj-t'iiKv. ,■^r^l^'rlr■;l'. nml I'r.jtw* uxlra. One jmirpisrt* & IuIjut v.;i rv, i i i k- If ]]roJucL'<. i OPTOELECTRONICS name in HANDI-COUNTERS Check These Incredible Features On The All New UTC3000 lOEli', Id i.-tUUc liunRc. fiiii]5>ly :]rtui/.]r.j^! • 10 Digit LCD Display. IHa rcsolulion lo over 150 MHz direct. Eteadablc in bright ^un light. * RF Signal Strength Bargraph. 16 Set.fnieril, Zero. & Kiill Scale adju.stTnent. SRK Ihf Input sii»ii;il! • Super Sensitivity. ctmV 10.200MHl. <5mV to StiHz for elTicicnl antennii pickup. • 6 Functions. Frequency, Poriod, Hatie Tinte Intej'vnl. Average, &. Preacnie. • Hold BuCtun. "Looks in" your HKiKl Mt'iisurement FASTI • Extruded Aluminum Enclosure. Dcsi>,Tied to Hi every hand. • Priced Right; Only 8375. Includes Nicad:^. AC Chnrger/Adnptcr. Or Select Our Most Popular HANDI-COUNTEEt, the model 2Z10A IhitL set the slnndard in handheld frequency counter technolog>'I Value Priced at only $239. ProftfKsjiohjils iiiul Hobbyists sill over the v^'urld ha^'e cliaaen OEI for 13 year.s: Shouldn't YOUt MANDi-COUNTERS! ...Only fi-om OEI! Choose the model that fits your needs,,, and your budget! CALL NOW! Toll Free Order Line:l-800-327-5912 fl(305)77i-2050 • faxoosjt? 1-2052 ,5821 NE 14th Avenue • ft. Lauderdolf, FI. 33334 Vixit. MCrOl), £"ft..»h. ,^t.(l.^lrc^'pn.(3 Prn-nnnl Vhivk allm^ H ftx.uk.^ r>'r .Ship[jin]^. llunrllinH. iMiisimLiiii SlOi t".S. Jk E'i.niid.L. In ^'t. ;idd fl". ^rilt.s Ijiv KhjII-Ihu. I^FtHJiict unci .^tfrv^.^.^]fv t';itj»l^]t! jn...iit;ibk' on rrjum^^l. .jLilsidi'fL, nliTiL.nl/i1 tVS.A, 00 m lO CD O 17 CIRCLE 189 ON FREE INFORMATION CARD Learn to troubleshoot and service today's computer systems as you build a fully AT-compatible micro, complete with 1 m^ RAM, and powerful 20 m^ hard drive Train the NRI Way— and E^am Good Money Servicing Any Brand of Computer Jobs for computer service technicians will almost double in the next 10 years accOTding to Department of Labor statistics, mfildng computer service one of the top 10 growth fields in the nation. Now you can cash in on this exdting opportunity— either as a full-time industry technician or in a computer service business of your own— once you've mastered elec- tronics and computers the NRI way. NRI's practical combi- nation of "reason-why" theory and hands-on building skills starts you with the fundamentals of electronics, then guides you through more sophisticated circuitry all the way up to the latest advances in computer technology. nidhl^ ^> Ttsm With a Powerful AT-Compatible— Now with 20 Meg Haiti Drive and 1 M^ RAM! lb give you hands-on training wi^ the absolute in state-of- the-art computer technolccy, NRI includes the powerful West Coast 1010 ES computer as the centerpiece of your training. As you assemble this fully I§M AT-compatible micro from the keyboard on up, you actually see for yourself how every section of your computer works. You build this powerful West Coast 1010 ES computer, ail the while gaining a true mastery of computer electronics. Best ofall, it's yours to keep for all your professional and personal computing needs. You assemble and test your computer's "intelligent" keyboard, install the power supply and 5Vi" disk drive, then interface the high-r^olu- tion monitor. But that's not alL Your hands-on training continues as you install a powerful 20 megabyte hard disk drive— today's most- wanted computer peripheral— now included in your course to dramatically increase the data storage capacity of your com- puter while giving you light- ning-quick data access. Plus you work with exclusive word processing, database, and spreadsheet software, yours to use for your own professional and personal applications. As you build your com- puter, performing key demon- strations and experiments at each stage of assembly, you get the confidence-building, real- 18 Your MR) computef training includes all this: • NRI's unique Oiscovery Labf^ for circuit design and diagnosis • NRI's hand- held digital multimeter featuring "talk-you- thtough" instnictions on audio cassette • A digital logic probe that lets you visually examine computer circuits • The new AT-compatible West Coast 1010 ES computer with high-speed 80286 4 CPU, 101 -key "intelligent" lase software • Reference manuals with programming guidelines and schematics kAj NOW! AT-compatible computer and 20 meg hard drivel prepared to take advantage of todays oppor- tunities in computer service. You leam at your own convenience in your own home. No classroom pressures, no ' night school, no need to quit your present job until you're ready to make your move. And all throughout your training, you've got the fuJl support of your personal NRI instructor and the NRI technical staff, always ready to answer your questions and help you whenever you need it. FREE 100-Page Catalog Iblls More world experience you need to woi^ with, troubleshoot, and service today's most widely used computer systems. New! Explore the Latest Advances m Voice Synthesis Now NRI also includes innovative hands-on training in voice synthesis, one of today's most exciting and wide- ly applied new developments in com- puter technology. You now train with and keep a full-featured 8-bit D/A converter that attaches in-line with yoiir computer's parallel printer port. Working with the exclusive text-to-speech software also included with your course, you explore the fascinating technology behind both digitized and syntheadzed com- puter speech. NRI's new handson training in voice synthesis is just one more way you get the confidence-building experience you need to feel at home with the latest advances in computer technology. Send today for NRI's big, 100-page catalog that describes every aspect of NRI's innovative computer training, as well as hands-on training in other growing high-tech career fields. If the coupon is missing, write to: NRI School of Electronics, McGraw-Hill Continuing Education Center; 4401 Connecticut Avenue, NW, Washington, DC 2000a School of Electronics No Experience Needed, NKI Buads It In This is the kind of practical, hands-on experience that makes you uniquely McGraw-Hill Continuing Education Center 4401 Connecticut Avenue, NW Washingt»n, DC 20008 IBM Kid ATm» Mk^sh* CoqxfvtkB SEND TODAY FOR FREE CATALOG! For Car«T course approved under G] Bill Li check f^^ details. McGraw-Hill Condnuin^ Educaliofi Ccnicr 4401 Connctticul Avenue, NW, Wasjiingtor, DC a»Og HicHECKONE FREE CATA LOG ON LV p Teleconranmications n Computer Elerlmnics Q induarial Btaronio LJ TV /Video/ Audio Sereieing p Elecnonic Circuit Dcsitn 11 Roboiics □ Baric Electronics D Elecironic Music Technology p Bootke^jing & Accounting D Security Elect rooics o Building ComtructJon n Digital Electronics Servicing p Automolivc Servicing i^nii O Air Conditioning. Hcatii:ki;> & Rcfriigcration O Smiiil En^Dc Repair n EltctriciaD □ Locksmithing. D Travel Careers □ Writing G PaialeBal O Computer Pro^Tanucing Name (Please [irini) Age fity/Siaic/Zip We^ll ^vejoit Somorrflw, I CD Afoedited Membs- Naiioanl Hmie Study Couodl 3-1 1 I 21 '>{X This is what C«> sounds like. ;«='. z Ml-. UA- .">--3.'^ ■ v' Wr . 'l'.<^yr,>y: ^'■..■_' ■'•'. "V-^"" h: :, This is what C9J looks like. (•) is the symbol for the new Sound Retrieval System tliat lets you experience true 3-D sound from two ordinary loudspeakers. Read that last sentence again. You probably still won't believe it. But it is real. h fact, ( • ) won the Grand Award for Audio Tech- nology in the "Best of What's New", Popular Science , December; 1989. Until now the quest for life-like 3-D sound has involved ever more sophisticated, complicated and expensive arrays of hardware. Until now. Because the engineers at Hughes Aircraft Company began asking some new questions about sound itself. Instead of concentrating on hardware, they analyzed the way the ear processes sound. They discovered that the subtle restoration of certain frequencies in recorded audio can duplicate the way your ears locate sound. Ah ha! Then they fiddled around with their new techno- logy until they not only perfected it, they made it affordable for commercial applications. To experience the uncanny realism of this new kind of sound is . . . well, uncanny. You can get up and walk around the room and the sound image doesn't change. You don't have to stay in the "sweet spot" • created by delay arrays and surround-type matrices. And you won't find the "hot spots" you get with multi- ple speaker arrays. Will ( • ) replace all those speakers? Len Feldman, in the September 1989 issue of Radio Electronics wrote, "The demonstration was so dramatic and effective that people couldn't help but look for additional hidden speakers." So forget expensive surround-type speaker matrices. You don't need to buy a roomful of speakers and sacrifice a lot of square feet of Mving space to house them. All you need is (•). We'U bet you're still skeptical, and will be until you actually hear ( • > for yourself. Which you can, today, on Sony TV sets. Imagine that You can buy a Sony TV with buOt-in sound that will make you want to throw rocks at your stereo system Several other major electronics companies are poised to announce(«> on their products. So, when you do look for your new audio system, look for (•). HUGHES Subsidiary of GM Hughes Electronics IwinRiidonintiad.axijadHu^iesMiaDekiitniiicSi'sUnsDht^^ laiisatiadfimiiK^Hi^f^AimaitGiiifBiiyDl^SD QRCLE 192 ON FREE INFORMATION CARD Mnsmn Coordinated Time Link Model CTS-IO Computer Time Standard CO o z O iicU:c Co CIRCLE 67 ON FFIEE INFORMATION CARD Instrumeniallon Products Division 3SS3 EuRin Eoad, Sar Diego. C* 9212J-189S (619) 49S-52O0 - FAX (619) 263.0172 • TLX 249031 Outside CaJilbmiiI-800-854-2703 Wtliin Califomla 1-SOO-2Z7-97S1 © t990 S«kman IndimriaJ Corponlioii. Specifimions su1i^[ IDdlKngt wtl^auL notice. Flulf 111 FcgtstsKf IndeniFb dJohnRutaM^Ca.Ltc JM 90-0) -1090 CIRCLE 98 ON FREE INFORMATION CARD Z s m S C3 m 33 to o 25 :MViJ;OI.|i|>^i; Use the Free Information Card for more details on these products. COMPUTER-CARE KIT. To help PC owners keep their systems in opti- mum operating condition, Philips Consumer Elec- tronics has introduced the SBMW07X01 computer- maintenance kit. The kit contains everything needed to properly main- tain an entire dual-drive PC system. Included are: CRT cleaning solution, absor- bent towelettes, keyboard and plastic cleaning solu- tion, swabs, disk-drive cleaning solution, with both 3Vi- and 5y4-inch cleaning diskettes, printer platen cleaning solution, special head-cleaning material, and a detailed instruction CIRCLE Id ON FREE INFORMATION CARD siimer Electronics Company, One Philips Drive, P.O. Box 14810, Knoxville. TN 37914-1810; Tel. 615-521-4499, manual. The SBMW07X01 dual- drive computer care kit has a suggested retail price of $49.95.— Philips Con- POWER-SWITCHING REGULATOR IC. Avail able in both commercial and industrial temperature- range versions, Motorola's monolithic power-switching regulator IC's with on-chip output switch are capable of controlling currents in excess of 3.0 amps. The IC's have a wide range of applications, including being used as a DC-to-DC converter in cars, consum- er products, appliances, computers, and industrial equipment. In switching power supplies, it can be used in on-card power reg- ulation and post regulation. Each IC contains the pri- mary functions required for DC-to-DC converters and is designed to implement CRAMOLIN' DeOxidizer DfOXIOtZES • CLEANS * PRESERVES • LUBRICATES • UWRQyES CONDUQIVITY hi/^MiniktiMinQSiil! . tWAOUN'- OeOiddizet . . js u fosturting deoxidizing soiutiof) fhot deans, piesenies, ond lubricotes oil inetBl surfote^ including gdd. When opi^ied fo inetol (onttitts, connectorj Odd ofter metnl surfaces, CRAMOLIN® DeOxiilizer removes reaslti^e oxides ond forms ptoteclire moiecjiot loyei that adhefes to rnehl surfaces, preventing fuhire oxi- dalioFi. CRAMOLIN* DeOxidizer maintains moximum electrical cotiductivilv, reduces wear, J'Snd has excellent migratioi properties. /DM1 FOR: • Switches S fieloys • Connecting Cobles £ Moptors • Edge Ctinnectots • Tefminol Stiips • Plugs I Sockets • GoU Plnted Connettois • PolMiliometeis • Bolteiy Contntts USED BY mOS[ WHO Dimm IHl UST; • Sell S Howell • Copiicl Recoiii! • Delliy UiboiBtotles • Hewlett Pwkoiti • lolin Flute Mfg. • MdntMli Labs •MCI (Sony) •Motoiofc 'NASA •Nnkotnidii •ECA •Switthtioft •im 1956 I LABOBATOHIES, INC, RO.BDxJ»£siMii(fa,CA920ZM051 [619) 743-71^3 •F»;:(6)9)74MW * EC'Anaitiie 11/ LMlt LdlEiitt ■ OzcM 5>T« ProfiitrdPiti + ChiEii^[i CampJilBEy Dlipsni CABLE - TV ■FOR ELIMINATION OF SEVERE INTERFERENCE •FOR "CENSORING- OF ADULT BROADCASTS . ATTEI^UATION - 45 dS TYPtCAL ■ BANDWIDTH ■ A MHi AT S dB POINTS ■ INSERTION LOSS - 2 dB HODCL TUNING RANGE CHAMHei3 PAft)^>fP PRC£ SHipnNd 2W 50*6 MHt 2.3(or6inet«FhAm] SO-3O0 WMt w NO SHIPPING Of COO. CHARGES 4eFM ee.ioi MHi 4.S C im inv FM1 M-SOO MHe no 1*t7 12(1- 144 MHz H(An6(8l IS (CI 17tD) iatm MHi m 1822 UtVi MH! U(E| 1S(F| M(G1 21(H 122(1) ia-iOO MHz t30 713 iT<-:ie UHi ?.«.S.10.11.12.13 SO-400WH1 too 3 for $75 - 1 for $200 - mix or match CALLTOLLFFtEEFORC.O.D ORSENDCRECKTOORDER FA ST DELIVERY 30DA¥MONE¥BACKaUARANTEE(3FILTERLIMIT) Star Circuits p. O. Box 94917 Las VegaSf NV 89193-4917 1-800-433-6319 26 CIRCLE 50 ON FREE INFORMATION CARD CIRCLE 17 ON FREE INFORMATION CARD step-up, step-down, and voltage- inverting applica- tions with a minimum number of external compo- nents. Key features include operation from 2,5- to 40- volt input, precision 2% ref- enence. a controlled duty- cycle oscillator capable of operating at over 100 kHz, and low standby current of 6.0 mA. The gated-os- cillator control mode re- sults in simplified, low-cost implementation of voltage- converter designs. In addi- tion, functional features — including a programmable current limiter, bootstrap, and MPU reset — make it easy to achieve less com- plicated designs at lower cost. Designs using the MC34163 do not require complex loop compensa- tion (as do pulse-width modulated control-mode systems), which results in fewer external compo- nents, simplified IC design, and reduced die size. The devices are available in a 16-pin dual-in-line pacl o 27 standard sine wave output can be converted to a square or triangle wave by ciianging one internal wire. Instructions are included to re-adjust or change the five CIRCLE 19 ON FREE INFORMATION CARD fixed frequencies: 20 Hz, 1 kHz. 3 kHz, 10 kHz, and 20 kHz. The 125B features a 0-20-kHz automatic sweep, and a manual fre- quency control that can be set from to 20 kHz. Once set, the output amplitude remains flat from 20 Hz to 20 kHz (±1/4 dB). A spe- cial regulator circuit allows the two batteries to change from 9 volts to 5-1/2 volts, with no change in ampli- tude or frequency. The model J25B sweep generator costs $76.00. — Production Devices. 356 North Marshall Ave- nue, El Cajon, CA 92020; Tel. 800-824-4226. SURFACE-MOUNT TRIMMER. A versatile, single-turn, open-frame trimmer from Bourns, inc. saves valuable circuit board space and is simple to automatically pick and CIRCLE 20 ON FREE INFORMATION CARD place. The model 3363 sur- face-mount trimmer boasts the industry's smallest 3- mm design and meets both EIA and EIAJ standard board footprints and pack- aging requirements. Typical applications are in pocket and hand-held pagers, vid- eo cameras, cellular-phone handsets and base sta- tions, office-automation equipment, computer pe- ripherals, and home securi- ty sys tern s . S u perior termi- nation-pad geometry re- sults in improved wave and reflow soldering. A perma- nent coating over the re- sistor element protects it from harsh fluxes, solder- ing, and cleaning environ- ments. The standard resis- tance range is 100 ohms to 1 megohm with 5% max- imum contact resistance variation (CVR), The 3363 is packaged in an 8 milli- meter embossed tape. In low volume quantities, the model 3363 trimmer is priced starting at $0,395 each. — Bourns, Inc., 1200 Columbia Avenue, Riverside, CA 92507; Tel. 714-781-5500. PROGRAMMABLE CONTROLLER. Bridging the gap between desktop computer and dedicated controller in applications such as appliance timers, temperature controller, programmable tester hob- byist projects, and alarms systems, the BEaR-1FB controller also functions as a hardware/ software de- velopment tool or a micro- CIRCLE 21 ON FREE INFORMATION CARD o z o DC H (J 111 o < 28 Train at Home to be an Electronics Technician ! Professional training and Et|uipnicnt can help you qualifj for a dynamic, high-paying career in your spare time. Aij the demarnj for computers and micro- processors in business and manufacturing continues to grow, so does the need for qualified technicians. It's not unusual for ex- perienced technicians to earn from 535,000 to more than S40,000 a year,* Now there's a way you can train for this exciting field without interrupting your job or home life. Choose Vrnm These Programs of Study •Electronics & Microprocessor Technology •Industrial Electronics & Microprocessor Technology •Computer Servicing & Electronics Technology •Specialized Associate Degree In -Electronics Technology You Get Professional Equipment For Professional Training Etependingon the program you select, you'll perfect your skills using this advanced equip- ment, included in the price of tuition: i* !>4iuiu<; L' B Butvju ml L.ihikr BuieisLil'vp • IBM -Compatible Personal Computer • Digital Multimeter • Digital Logic Probe • Elenco Oscilloscope Evclusive Extras That Enhance Your Training Peoples College inttoduces some training firsts to make your learning experience more complete: • Accelerated Learning System — a scien- tifically proven study system that lets you learn faster and easier than ever before. •Optional One-Week Seminar — available with our advanced program?;. Conducted on our campus near Orlando, Fla. Not required for graduation, bin a valuable opportunity to fine tune your skills with personal guidance. •Video Tutor Training Tapes — give you a permanent, visual record of informative lectures and close-up demonstrations. •Experience Labs — professionally designed experiments that give you hands- on "bench" experience. •Industry Certification Training Guide — provided with three of our programs. Gives you first-hand insight into the examination you may take for your professional license. For COLOR CATALOG Mail Coupon or Call TOLL FREE 1-800-765-7247 Pi-i'^^fitttl^ ogtteii mth in Ultitvd Siafea. Ccumdn. Ftierio RiiVj ii/Kt Virgin htaiKJs. No Obligatioi:. No saten pt^ntHt wiH cati Our programs are accredited by the Accrediting Commission of the National Home Study Council ■X - 'YES! I would like to know more about your training programs. Send a catalog to: Name Address City State E _Zip_ Peoples College 'OF INDEPENUtNT STUDIES Z33 Academy Drive • P.O. Box 421768 Kissimmee, PL 34742-1768 MfmhiTL r>.l.. Pmpk". tinmp R1190 CIRCLE IBB ON FREE INFORMATION CARD computer lab trainer. The controller, from Blue Earth Research, is based on the Intel 83C51FB micro- controller with resident floating point BASIC inter- preter and debug monitor. The BEaR-IFB is simple to wire and program, requiring only a 6— 16-volt power source and any terminal or PC that supports serial communications. Housed in a high-impact plastic case, the unit features 32K bytes of RAM; a real-time clock/calendar; an 8-chan- nel. 8-bit A/D converter; a precision 5-volt regulator: a 10-year lithium backup bat- tery: and a dual RS-232C driver/ receiver for serial communications. The SfaR-/Fe controller costs $199,00, A complete system — including the controller, user manuals, a power supply, applications board, and serial interface cable — is available for $299,00 —Blue Earth Research. 310 Belle Ave- nue, Mankato, MN 56001; Tel. 507-387-4001; Fax 507-387-4008. BNC ATTENUATOR KIT Putting the proper at- tenuators at the fingertips of radio and TV broad- casters, RF design engi- neers, and mobile commu- nications manufacturers, Test Probes, Inc. has intro- duced its model TPI1200 CIRCLE 22 ON FREE INFORMATION CARD BNC attenuator kit. The kit contains one each of the four most frequently used attenuators — in 3-, 6-, 10-, and 20-dB ratios — as well as one 50-ohm feed- through and one 50-ohm BNC termination. The at- tenuators feature thick- film circuitry for low reactances and a frequency range of DC-1 GHz. Built for du- rability, the attenuators have a rectangular shape to keep them from rolling off a bench, and feature a "drop- proof" shock-resistant de- sign. The model TPI-1200 BNC attenuator kit costs $110.00.— Test Probes, Inc., 9178 Brown Deer Road, San Diego, CA 92121; Tel. 800-368-5719. CROSS-NEEDLE SWR/ WATTMETER. The MFJ-817 114/440-MHz SWR/Wattmeter from MFJ Enterprises displays forward power, reflected power, and SWR at a single glance. The peak-and-aver- age-reading instrument also provides two power scales— 200 or 20 watts forward and 5 or 50 watts reflected The MFJ-817 is housed in a 7%-4'/a-3y2- inch black aluminum cab- inet. It features a meter lamp and a large, two-color easy to nsad meter. The MFJ-S?7peak-read- CIRCLE 23 ON FREE INFORMATION CARD ing cross-needle SWR/ wattmeter, including a one- year unconditional warran- ty, costs $79.95. An op- tionaHIO-VAC adapter iMFJ-1312) for the meter lamp costs $12.95.— MFJ Enterprises, Inc., P.O. Box 494, Mississippi State, MS 39762; Tel, 601-323-5869; Fax 601-323-6551. STANDARD FEATURES I FULL FUNCTION: Direct and prescaled Frequency, Periods (or averages). Time Intervals (or averages), Frequency Ratios, I WIDE FREQUENCY RANGE: 10 Hz to 2.4 GHz, useful 1 Hz to 3 GHz i HIGH RESOLUTION: 1 sec gate time displays 1 Hz in 200 MHz. I HIGH ACCURACY: TCXO ± 1 ppm standard 116 element signal strength meter 1 10 digit LCD readout I NBS traceable calibration ONLY $579 OEI's mode! UTC 8030 is a full- featured Universal Counter-Timer with a Frequency Rnder buitt in a unique bench/portable enclosure. The Frequency Rnder's 10 mV antenna sensitivity and NtCad batteries provide true off-the-air measurements at maximum distance from any transmitter up to 3 GHz. OPTOELECTRONICS, INC. 5621 NE14TH AVENUE FORT LAUDERDALE, FL 33334 FLORIDA PHONE (305) 771-2050 CIRCLE 190 ON FREE INFORMATION CARD OPTIONS TCXO 80 $125 High precision 2:0.1 ppm sealed 10 MHz 20''-40°C temp controlled xtal oscillator NICAD 80 $75 Internal rechargeable NiCad battery pack for >2 hours field use without recharging BL80 $40 Display backlight for nighttime use ASK ABOLTT USEFUL ACCESSORIES 1-800-327-5912 FAX (305) 771-2052 to O 29 DSP ANALYSIS SOFT- WARE. Alligator Tech- nologies' Fourier Perspec- tive III digital signal pro- cessing (DSP) analysis software with Data View graphics is designed to run on any MS-DOS-compati- ble computer (IBM PC. XT, AT 386. 486, PS/2, and compatibles using MS DOS 3.0 or higher and equipped with a minimum ■ W^ ■ M f \ ^^^^:.m^ 3^- J , Ni^in S^ CIRCLE 24 ON FREE tNFORMATION CARD of two floppy-disk drives or one floppy and a hard disk, and 512K of RAM memo- ry). Data View provides publication-quality graph- ics; supports a variety of printers and plotters; and requires a CGA, Hercules monochrome-compatible, EGA, VGA, or equivalent graphics card. Fourier Per- spective II uses the Prime Factor FFT subroutine li- brary to operate on com- plex data sets as large as 65,520 paints in one di- mension. Single and dou- ble precision IEEE floating point formats and integer data format are supported. The DSP analysis software provides for high-perfor- mance calculations, and the use of on optional 8087 math coprocessor signifi- cantly increases the speed of all arithmetic operations. The software features one- dimensional Fourier trans- forms and graphics, digital filtering, linear systems functions, apodizing and windowing, convolution and correlations, file arith- metic and complex conju- gates, media window filter- ing, and other mathemati- cal operations. It also provides a Lotus 1-2-3 in- terface. Fourier Perspective III with Data View costs $695.00, with multiple use licenses available. — Al- ligator Technologies, 17150 Newhope Street #114, PO- Box 9706, Fountain Valley GA 92708; Tel. 714-850-9984; Fax 714-850-9987. FOUR-WAY ELEC- TRICAL TESTER. An in expensive tester from A. W. S perry Instruments, the model ET-204A, allows technicians and hobbyists to check 110. 220, 277, and 460 volts AC/DC using just one compact in- strument. The ET-204A four- way tester has individ- ual resistors and bypass re- sistors for each voltage range. The EJ-204A four-way electrical tester costs $3.50 —A. W. Sperry CIRCLE 2S ON FREE INFORMATION CARD Instruments, inc., 245 Marcus Boulevard, Haup- pauge, NY 11788; Tel. 516-231-7050. RS-232/RS-422 LINE DRtVERS/RECEIVERS. The AD230 line of RS-232 and RS-422 line drivers/re- ceivers represents Analog Devices' entry into the data-communications mar- ket. The monolithic devices both transmit and receive C/3 g z o cc t- o LU Q < 30 THE HOUSE SITTER THAT DOESN'T NEED A KEY Use the keyi}oard to set emergency phone numbers, high and low lemptratures, listen- in _ time and more ALEKT/CANCEL key cancels automatic dial-out, allows ymi to answer phone WHAT IS key lets you listen to function settings and dial-out numbers "This is 555-3210. Alert condition is OK. Temperature is 65°. Electricity is on. Sound level is OK." Monitoring your home from work or a vacation spot is made easy with the Heath/Zenith House Sitter Security Monitor/ Dialer, Monitors Your Home When you call, the House Sitter will report on the AC electric power, the room temperature - comptu-ing it with high and low limits you've already set, loud noises such as burgliu alarms and fire alarms , the unit's own battery backup condition, and an additional alert condi- tion. You can even listen to the sounds in the room using the built in microphone. £utuididr>' of Bull Dita S^i^nu. Inc. Use tlie keyboard to . ask for information SET key allows you to change previous settings SENSOR ONIOFF key chooses the functions to report ONLY $149.95 Dials Out In Alert Conditions Set the unit to call out to your office, neighbors' and rela- tives' to announce any alert conditions that are outside preset limits. Up to four numbers can be programmed. Order Toll Free 1-800-253-0570 The SD-6230 House Sitter is yours for only $149.95*. To order, call toll-free 1-800-253-0570. VISA. MasterCard. American Express or your Heath Revolving Charge card accepted. Use order code 601-034. See our full line of electronic products for the home in the Heathkit catjflog - call 1-S00-44-HEATH for your FREE copy. Heath Benton Harbor. MI 'AddHitma! for ihippir^ and handlirfi. Add •*% mI» laS f&f Ml dellvtfrt*, add 6*- ijjet u^ ftrf CA dclivCTtC>, CIRCLE 86 ON FREE tNFORMATION CARD multiple lines of serial RS-232 and/or RS-422 data, replacing compli- cated, discrete solutions. All are manufactured in low- power CMOS or BiCMOS, require few or no external components, and are pin- compatible witfi existing in- dustry products. Eleven configurations — ranging from two drivers and two receivers with the 14-pin AD231 to four drivers and five receivers with the 28- pin AD241 — are offered for a variety of applications. Maximum no-load power dissipation is 50 mW with most of the devices. Nine of them require only a sin- gle -l-5-volt supply, and four of those feature a shutdown mode that re- duces power dissipation to 5 [lW for battery-powered applications. In addition to the AD230 line, Analog Devices intro- duced the AD401 and AD402. which are config- urable for either single- ended RS-232 or double- ended RS-422 communi- cation standards — or a mix of both. All 13 devices are available in a variety of packages and temperature options. CIRCLE 26 ON FREE INFORMATION CARD The AD230 family of RS-232/RS-422 line driv- ers/receivers is priced starting at $2.70 each, in quantities of 100. Pricing for the AD401 and AD402 starts at $9.00 each, in quantities of 100. — Ana- log Devices, Inc., 181 Bal lardva le Street , Wilmington. MA 01887; Tel. 617-937-1428. OXIDE-PENETRATING TEST CLIPS. Six DIP-clip test adapters from Pomona Electronics penetrate the oxide build-up on DIP IC's that have been exposed to contaminated environ- ments. The devices func- tion similarly to standard test clips, but feature a roughened, stainless-steel surface coating on their serrated contacts to pro- vide good electrical con- nections on contaminated surfaces. The clips provide hands-free testing of stan- dard 8- to 40-pin DIP IC's on high-density PC boards. The 1.02 mm C0.040 inch) contacts are separated by molded insulating barriers, allowing connection to be made on "live" boards without accidental shorting of adjacent contacts. The upper contact pins accept wire wraps or miniature test clips. Models 5649, 5650. 5692. 5694. and 5695. with 8, 14. 16, 20, 24, and 40 pins, respectively, range CIRCLE 27 ON FREE INFORMATION CARD in list price from $9.70 to $31.00 each.— ITT Pomona Electronics. an ITT EMC Worldwide Company. 1500 East Ninth Street. Pomona, CA 91769: Tel. 714-623-3463: Fax 714-629-3317. B-E The Powerful 68000 Training and Development System Introducing a 68008 based microprocessor development system for the educational environment. Poweifu!; The Learning Tool is built around the powerful 68000 family architecture. Users are not forced lo learn on an archaic full 8-bit machine; instead they can hone their skills on a 32-bit proces sor in a family that will dominate the market. The 68000 family covers the spectrum of microprocessor applications. The 68008 provides an excellent introduction to this family. Expandable: The Learning Tool has a removable breadboard with access to the system's signals. This allows the design to be implemented apart from the Learning Tool and allows previous designs to be easily reconnected. Further, the Learn- ing Tool has two expansion slots which can be used to expand the basic capabilities of the system as well as for wirewrap experiments. Hardware Features: 64k x 8 static RAM (32kb battery backed up), write protectable in 8kb segments; 32k x 8 EPROM; 2 serial ports; timer/counter/square wave generator; expansion slots; removable bread- board (also sold separately); built-m lo^c probe; dual speed 8/2 MHZ clock; push button reset and abort switches Software Features: Powerful debu^er including - deposit, write only; examine, read only; disassembler; 7 permanent breakpoints; 1 temporary breakpoint; single step instruction execution; memory or register watch; download from either serial port; saved serial ports settings in RAM; calculator; memory verification; I/O trap routines Optional; experiments such as an EPROM programmer; wdrewrap cards I . S . S . C 30 day money back guarantee f^P^^^~^^^ Call Now: (602)820-9176 CIRCLE 193 ON FREE INFORMATION CARD LS.S.C. Learning Tool: $749.00 z § 6S21S.Ternj««TeinpeAZS52S3 ^ Ph: C602)S20^9n6 ^ COD, Cash, M,0„ Personal Chect 5% jhlppin& handling ^ for continental U.S.A. 1S% oucslde continental U.S.A. ^ In AZ3ddi5,6%Hlc5 tas ^ Allow 3 weeks for deliveiy (n 31 CO o z o UJ O Q < DC ROGER HAINES ON RE- PORT WRITING: A GUIDE FOR ENGI- NEERS; by Roger Hain- es. TPR, Division of TAB Books Inc., Blue Ridge Summit, PA 17294-0850; Tel. 1-800-233-1128; hardcover; $22.95. A common gap in engi- neers' educations is in the field of written communica- tions. Althougfi writing is often neglected between all the mandatory "num- bers" courses, good, clear report writing is often an essential element of a ca- reer in engineering. For en- gineers who find it difficult to express ideas in words, Roser Haines on REPORT^ WRITINC A (jitidtfur En^nta CIRCLE 28 ON FREE IN FORMATION CARD this book demonstrates how to get ideas across to both technical and non- technical audiences. It shows engineers how to produce concise papers, using a proven approach that consists of a series of steps. The book explains how to clearly define the purpose and scope of a re- port, find and research in- formation, evaluate the data, develop a writing style, choose the format and appearance of the re- port, effectively put graph- ics to use, use the advanced features of word processing, and compile appendices. A chapter on oral presentations, with ad- vice on fielding questions, using visual aids, and using effective timing, is also in- cluded. Each topic is clear- ly explained and illustrated with real-life examples. 1990/91 DC POWER SUPPLY CATALOG WITH ELECTRONIC LOADS. Hewlett-Pack- ard Company, Inquiries, 19310 Pruneridge Ave- nue; Cupertino, CA 95014; 1-800-752-0900. Containing specifica- tions, drawings, and ap- plications information for Hewlett-Packard's line of power supplies and elec- tronic loads, this 128-page catalog provides easy-to- use informational tables to simplify selecting the right model. More than 80 mod- els, ranging form 10 watts to 1 1 kilowatts, are in- cluded. Power supplies are grouped into HP-IB-con- trolled system, bench, lab, industrial, and special-pur- pose categories. Also in- cluded are HP's electronic- load products, ranging from 1 50 to 600 watts and offered in both stand-alone and mainframe-based con- figurations. The applica- tions sections cover AC- power connections. DC- output connections, and analog-programming meth- ods. A separate section contains a glossary of power-supply terms and their definitions. AN INTRODUCTION TO APPLICATION SPECIFIC INTEGRATED CIRCUITS; by Malcolm R. Haskard. Prentice-Hall, Engtewood Cliffs, NJ 07632; hard- cover; $30.50. tJkPPLICATION jEntkgrated iSlRCUITS CIRCLE 29 ON FREE INFORMATION CARD CIRCLE 30 ON FREE INFORMATION CARD While application specif- ic integrated circuits (ASIC's) are not a new technology, they are be- coming increasing impor- tant in the world of electronics. This book pro- vides an introduction to ASIC technology for both students and profession- als. It offers a detailed over- view of ASIC's, and in- depth looks at each of the major technologies, with a separate chapter devoted to arrays, standard cell, full custom, and programma- ble logic devices. The crite- ria for selecting the most appropriate silicon tech- nology for a product are ex- amined. The book describes the CAD methods used in the design of ASIC's. A chap- : ter explaining technologies that can be used to better train undergraduates in the '__ use of ASIC's is also in- cluded. ARMOR-FLEX ANTEN- NAS FOR PORTABLE TWO-WAY RADIOS AND CELLULAR PHONES. The Antenna Specialists Company, 30500 Bruce Industrial Parkway, Cleveland, OH 44139- 3996; 216-349-8400; Fax: 216-349-8407. Virtually every portable application for low-band, VHP. UHF. trunking, and cellular communications is covered by this full-color brochure and selection guide. It provides a cross- reference chart for quick, accurate antenna selection according to radio type, connector requirements, operating frequency, and antenna style. Antennas for i\»table Two- Way Radios and Cellular Phones l\ CIRCLE 31 ON FREE INFORMATION CARD 32 Electra/ilcs, DlfDDDllD CALL NOW AND RESERVE YOUR SPACE • 6 X rate $940.00 per each insertion. • Fast reader service cycle. • Short lead time for ttie placement of ads. • We typeset and layout thte ad at no additional charge. Call 516-293-3000 to reserve space. Ask for Arline Fishman. Limited number of pages available. Mail materials to: mini-ADS. RADIO-ELECTRONICS, 500- B Bi-County Blvd., Farmmgdale, NY 11735. FAX: 516-293-3315 SIMPLY SNAP THE WAT-50 MINIATURE FM TRANSMITTER on top of a 9v battery and tiear every sound in an entire house up to 1 mile away! Adjustable from 70-130 MHZ. Use with any FM radio. Complete kit 529.95 + $1.50 S + H. Free shipping on 2 or more! COD add $4. Call or send VISA, MC, MO. DECO INDUSTRIES, Box 607, Bedford Hilts, NY 10507. (914) 232-3878. CIRCLE 127 ON FREE INFORMATION CARD CABLE TV CONVERTERS AND DE- SCRAMBLERS SB-3 $79.00 TRl-BI S95.00 MLD-$79.00 M35B S69.00 DRZ-DIC $149.00. Special combos available. We ship COD. Quantity discounts. Call for pricing on other products. Dealers wanted. FREE CATA- LOG. We stand behind our products where others fail. One year warranty. ACE PROD- UCTS. P.O. Box 582, SacD, ME 04072 1 (800) 234-0726. CIRCLE 75 ON FREE INFORMATION CARO FREE CATALOG OF HARD-TO-FIND TOOLS is packed with more than 2000 quality items. Your single source for precision tools used by electronic technicians, engi- neers, instrument mechanics, schools, labo- ratories and government agencies. Also contains Jensen's line of more than 40 tool kits. Send for your free copy today! JENSEN TOOLS INC., 7815 46th St., Phoenix, AZ 85044. (602) 968-6231. CIRCLE 115 ON FREE INFORMATION CARD THE MODEL WTT-aO IS ONLY THE SIZE OF A DIME, yet transmits both sides of a tele- phone conversation to any FM radio with crystal clarity. Telephone line powered - never needs a battery! Up to Vj mile range. Adjusta- ble from 70-130 MHZ, Complete kit $29.95 + $1.50 S->-H, Free Shipping on 2 or more! COD add $4. Call or send VISA, MC, MO. DECO INDUSTRIES, Box 607, Bedford Hills, NY 10507. (914) 232-3878, CIRCLE 127 ON FREE INFORMATION CARD ELEVEN-PIECE RACHET TOOL KIT Includes reversible ratchet handle, extension bar, six bits, two precision screwdrivers, and a cutter. Comes in fitted case. Get one for your shop, another for your car, another for your tool kit. To order send $11.75 USA shipping only. ELECTRONIC TECHNOLOGY TODAY INC, PO Box 240, Massapequa Park, NY 11762-0240. NEW XST500 SUPER-MINIATURE FM transmitter uses Surface Mount Technology (SMT)! Own the smallest high performance FM transmitter available. Transmits whispers to any FM receiver up to a mile away Uses 9V battery. Complete, easy to assemble kit, with SMT components already assembled to cir- cuit board. $39.95 Cash, VISA, MC. COD add $5. XANDI ELECTRONICS, 201 E. South- ern Ave., Suite 114, Tempe, AZ 65282. 1-602-829-8152, (1-800-336-7389 orders only). CIRCLE 183 ON FREE INFORMATION CARD APPLIANCE REPAIR HANDBOOKS— 13 volumes by service experts; easy-fo- und erstand diagrams, illustrations. For major appliances {air conditioners, refrigerators, washers, dryers, microwaves, etc.), elec. housewares, personal-care appliances. Basics of solid state, setting up shop, test instruments. S2.65 to $5.90 each. Free brochure. APPLIANCE SERVICE, PO Box 76S, Lombard, IL 60148. 1-(312) 932-9550, CIRCLE B4 ON FREE INFORMATION CARD < m CD m CD (D O 33 : C . -ill. --r .'--■■•: .'i- .,.,.■. '/■ ..■'' ■ -— -. J, '•■;- . '■ »h . .•>" ,■•! iivr ,.,1 l?."ife.- . ; cv-'i;--^'..:. ^•ni.y WARNING!! This article deals! with and involves subject matter and the use of materials and sub- stances that may be hazardous to health and life. Do not attempt | to implement or use the informa- tion contained herein unless you I are experienced and skilled with respect to such subject matter, materials and substances. Nei- ther the publisher nor the author make any representations as to the accuracy of the information contained herein and disclaim I any liability for damages or inju- ries, whether caused by or result- ing from inaccuracies of the I information, misinterpretations of the directions, misapplication of| the information or otherwise. ■ - . -■ <■ BUILD A •X: I i SER SYSTEM iolob: o z o (r 6 Q < DC 34 Visible-light laser diodes are here! In the first article of its kind, we'll show you how to build a handheld, rechargeable^ semiconductor laser system. ^■^ 1NTROOOCTION OF UA 1 has brought about . ^fis in our lives, from Ih ^^....Jtacet check^Bat counter "Star^BB" weapoT _ Very fevrWentiflc d^l^pments ye had anouch of aKmpact '" loth the In^ologlca^^^ ev- *"• ' world.^^ ^ " is an acronym for "li emissl^^^ radlatn^' Lasers are used including\_ printers, co: veying aids, c ers, bar-code ction ct-dlsc J 'ers, II shows, and severaTothers, Th_ helium-neon gas laser is one of the most familiar typelT bright red directional b>, been a workhorse for yeu. spite its fragile glass laser i and its requirements for cos. high- voltage power supplies. Bui laser diodes promise to open a whole new world of applications. To demonstrate how they can be used, we've developed a hand- held battery-powered laser that runs on four rechargeable bat- teries. The batteries are induc- tively charged using a special charger. The unit is shown In Fig. 1, How is that possible? The recently developed TOLD- 9200-series of laser diodes from Toshiba emit coherent laser light in the visible spectrum, and don't require a high-voltage power supply Because they're small, low-cost, and fairly rug- ged, laser diodes are well-suited for many applications. Before proceeding further, lets review some basic laser theory. but lirst we must talk about reg- ular light for a minute. When you turn on a light bulb. light energy is emitted in what Is referred to as "spontaneous" form. It is an integration of many individual atomic energy level changes, each producing its own little "packet" or photon of light ener- gy, with each photon having a particular phase. In the case of a light bulb, elec- trical energy "pumps" the fila- ment electrons to higher-than- normal atomic energy levels (see Fig, 2), Photons are emitted when the electrons return to their ini- tial states and give up that energy in the form of light. The frequen- cy of the light is dependent on the rence bmften'the pi^jpusly and n^kal ener^^evel eous emission is In dom (seflBig. 3). ke spontanfeus eml; laser Mbt is hl^H^irection The radraoit energy iM|leased in- step, or in synchroniSfet result- ; in coherent reinforced light ■;re all of the waves are in • In other words, all of the rays^te parallel ar' * wavela|^. lb ac quires tMkUie numbl^^excited toms in n^higher en qBy state eeds that of the initial^^rest ' . That condition, refei mlation inversion," . mall^^^sn't occl" ' must ^Bforced" of^miped. . Given^wipulatloi^^ersion. ISLcd atonF^^then lulated" to return to Ungwer cn^^^ state by the emissio er^^^ncident light of an a cent 31 is cahe!H|Hght wa'^nas shown in Fig. S^^oDtical alfav with mirrored e^^ ' sary to provii of stimulated" light. As showri'^B^ig. 6, . light is reflected b^^^id fo within its confines I^K. It is a powerful beam that isT exit the cavity as usei^, light energy A laser diode is similar tc , ordinary light-emitting diOu (LED) in that both are composeu-. of a semiconductor PN junction (see Fig. 7). An electrical potential causes a (low of holes and elec- trons that, upon recombination, emit light. The LED produces spontaneous light, while the laser emits light by stimulated emission. The laser diode also contains two reflecting mirrors that form what's called a Fabry- Perot cavity, and permit the emit- ted light to be highly directional, an important laser property. In spite of a laser diode's appar- ent physical ruggedness. it is very sensitive to temperature changes, electrical transients, and operating-current param- eters. It is totally unforgiving of errors, so our circuitry and con- struction techniques must lake that into consideration. ____. assoclalSid with la. wer in excess of 3 milliwatts. ipt energy, when coUlitiated, or viewed near-field, can cause retinal damage, so never look directly into the laser beam at through any lenses when the- ■ system is activated. The laser that we are building is a Class Ilia device, and rn,ust be in ^m- pliance with U!^^ safety st^- 1040. lO^d 1040,1^^ . Our delne must o^ff a label :e the oni^t^^wn In^K. 8. It ja label cof confomfSo classifi tions. .^^e outpi ve the foirawlng Ie "Avoid Exposure, Visible Laser ._ diation is Emitted Prom This "^ rer. La^ MA i^ ' #DO-40 m when 'ces of 1 's. Hln .is su^es Tb prevei. fies, be ^m^ not to lum ratings, even moiaen- r you co^^j^destroy^*'*" dlode'^^ause it t^||uire mo. curren^AuDroduce i^wted out- ut (whlal^ill quiclSwad to "^lure], l^^^ients o^%ykes o destroy thf device. 1 sinKSj^s requlr^^he amoun depen^vn whettl^^he device'^ will be^^d InternR^ntly or ^ . ep in^nd that '^nyiiperatC^^ise redt^^the olA^ for a gnijt curren. m^Asupplyi^Haore cur will ll^Ato a thei^^^roblem. Be atMte of elecnm^tic dis- charge ^^^haqiJliiqMBScr di- odes, NoraBSil^ ^is enfcty re- quires g r o itfUjStt^MilK^Mris t the hobbyist i hot humid d^g^^B|a'>iapon?.er or humidifiefliPma^mari a de- . grce of moisture in tn^ES^V^^t will reduce the static cl Do not operate the ur high-frequency or high , ^ pulse circuitry, an RF fiek Tcsla coil, plasma, magnetic di^^^g charge, etc. Never stress the di- as ode leads or distort the her- Ji metically scEiled case. The device ^ TOUCH SWITCH L1 IS IN THIS END PC BOARD FIG. 1 — OUR HAND-HELD LASER Is powered Irom four rechargeable Nl-Cd batteries, which are inductively charged. m o z O a: I- o LU should fit snugly into the heat sink cavity with minimal force, _Never touch the window because scratches and contaminants will distort and decrease the optical output. Use a cotton swab and ethyl alcohol to clean the window. Circuitry A laser diode operates like an ordinary forward-biased diode and shows the operating curve in Fig. 9. The vertical 'axis corre- sponds to optical output while the horizontal axis is the forward diode current, Iqp is the operat- ing current, which determines the optical output. Lasing starts at the threshold value (It-h)- The maximum rated input current must never be exceeded. How- ever, anything below ly,., will pro- duce the effects of a regular LED. The curve shows a very steep slope where laser operation takes place, and the input-current "window" on the horizontal axis is very narrow; consequently the driver circuit must operate with- in those limits or you 11 end up with one of the worlds most ex- pensive medium-powered LED's. The schematic of the hand- held laser is shown in Fig. 10. The Toshiba 9200 laser diode (D3) is actually an assembly that contains a laser-emitting section (LD) and a photodiode section (PD). The photodiode allows the circuit to monitor the laser di- odes output and to produce the feedback necessaiy to control the circuit and protect the diode from voltage transients. The laser diode is connected in series with current-limiting re- sistor R4 and the collector of Q4. The current through Q4 is con- > EXCITED LEVELS ■=0 BOTTOM LEVEL FIG. 2— LIGHT IS THE RESULT of radiation produced within an individual atom by an electron being "pumped" to a higher than normal energy level by an external energy source. FIG. 3— A LIGHT BULB EMITS "spon- taneous" light, which does not allow the energy packets to reinforce one another in phase or position. F, - INCIDENT LIGHT EMlTTtD LIGHT ^1 1 ' FIG. 4— WHEN MORE EXCITED ATOMS exist In the higher energy state than in the jnitiat or rest state, each energized atom is "stimulated" to return to its lower energy state by the emission energy, or Incident light of an adjacent atom. trolled by Q3, Zener diode D2 maintains the voltage across Q3, and R3 limits the Zener current. The collector current of Q3, which is also the base current of Q4, is controlled by its base which is connected across R5 and R6, Current from the pho- todiode develops a voltage across those resistors that is propor- tional to the optical output ener- gy. That constitutes the feedback required for output stabilization. Increased output causes QS to conduct less base current to Q4, resulting in less laser diode cur- rent. Potentiometer R6 presets the value of quiescent current. Capacitor C5 limits transients at the base of Q4 while C4 limits them from the Vj,^, line. The system turns on when Q2 is conducting and close to sat- uration. Touch-switch Si's elec- trodes consist of small pieces of metallic tape that, when bridged by finger contact, cause a small amount of base current to flow into Ql. The collector current of Ql flows into the base of Q2, causing it to saturate and supply current to the laser diode. Base current to Ql is limited by R2. while Rl and C2 reduce the cir- cuit's sensitivity to stray AC or static fields that could cause pre- mature turn-on. The laser is powered by four re- chargeable Ni-Cd batteries. They are charged by induction coup- ling to the charging module. The batteries are connected in series with rectifier diode Dl, LEDl, and the pickup coil, LI. High-fre- quency energy from the charger is coupled into the coil, and is rectified and filtered by CI. When the batteries are being charged LEDl turns on. The charger schematic is shown Fig. 1 1 , and a photograph of a prototype unit is shown in Fig. 12. It uses a 120-to-12 volt AC step-down transformer, Tl, whose output is rectified by di- odes D4— D7; capacitor C6 re- moves any ripples. Switch S2 I H LASER LIGHT (COHEREtJT RADIATION) FIG. 5~A LASER BEAM IS THE RESULT of an "in lock step" train of coherent lightwaves. 36 supplies power to the circuit, and LED2 Indicates when the power is on. The ground lead of PLl is connected directly to the metal chassis of the charger. The rectified 12-14 volts DC energizes a simple oscillator cir- cuit consisting of Q5 in series with L2. That winding couples energy into the pick-up coil (LI) of the laser section for battery charging. To charge the bat- teries, the pickup coil physically slides over the coil assembly of the charger module. No electrical connections are necessary to pro- vide the charging current. Coil L3 (which is wound on the same ferrite core as is L2), and resistor R9 provide the necessaiy PARTS LIST FOR THE LASER All resistors are 'A-watt, 5%, un- less otherwise noted. R1— 5.6 megohms R2, R5— 1000 ohms R3 — 470 ohms R4 — 15 ohms, V2-watt R4-a — 100 ohms (optional, see text) R6 — 5000 ohms, trimmer potentiom- eter Capacitors CI— 100 (jiF, 16 voits, electrolytic C2 — 0,1 fiF, 16 volts, ceramic disc C3— 0.01 jjlF, 16 voits, ceramic disc C4 — 1 [xR 16 volts, electrolytic C5— 10 M^F, 16 volts, electrolytic Semiconductors D1— 1N4001 diode D2— 1N5221 Zener diode (2.4 volts) D3— TOLD 9200 laser diode (Toshiba) LED1— yellow light-emitting diode LED3 — red light-emitting diode (for the simulated laser diode) Q1, Q3— PN2907 NPN transistor Q2, Q4— PN2222 NPN transistor Q&— L14G3 or ECG3036 phototran- sistor (for the simulated laser di- ode) Otiier components Bi-B4--1.26-volt Ni-Cd cell, VARTA 100 R.S. LI — pickup coil, 10 turns #18 wire, Vz- inch diameter SI — 2 pieces of adhesive- backed metal tape (see text) Miscellaneous: PC board or perfo- rated construction board, small transistor socket (for laser diode), special aluminum heatsink and di- ode retainer with hardware, #24 vi- nyl wire, #20 vinyl wire. 7%-inch long by 1-incli diameter by V'le-inch wall thickness (transparent or col- ored), '3/i6 plastic rear cap, lye-inch by VB-inch focus tube, 1 x 6 mm short focal length lens, 1-inch plas- tic caps, ^a-inch diameter shoulder vrasher (to mount lens on), warning labels, etc. REFLECTOfi 1 ACTIVE MEDIUM REFLECTOR 2 FIG. 6— AN OPTICAL CAVITY having mirrored ends provides the right amount of stimulat- ed energy for laser light. Light is reflected back and forth within Its confines until it is a powerful beam that is allowed to exit the cavity as useful laser radiation. TYPET" w ty(^ yy jw( y/ \ -'--;6t^-"->'' / -yy:'' y I REFLECTING FACETS SPOHTTAKEOUSLy EMITTED LIGHT LlGHT-EMlTTIfJG DIODE LASER LIGHT LASER DIODE FIG. 7— A LASER DIODE IS SIMILAR to an ordinary LED, except that the LED produces spontaneous light, while the laser emits light by stimulated emission where the wave- lengths and temporal relation are coherent. A laser diode also contains two reflecting mirrors that form a cavity and permit the emitted light to be highly directional. W^^IIJMgl LASER RADIATION- DO NOT STAHE INTO BEAM OR VIEW DIRECTLY WITH OPTICAL INSTRUMENTS CLASS Ilia LASER PRODUCT FIG. 8— ANY LASER DEVICE must contain warning labels according to the specific type of device. Our hand-held laser must display this warning, in addition to a label stating that it conforms to specifications and a warning at the laser aperture. feedback to sustain oscillation. Resistor R8 initiates the action by turning Q5 on. A resonating capacitor (C7) is connected across L2 to adjust the frequency to approximately 250 kHz. Construction All of the parts are available from the source mentioned in the parts hst. A foil pattern has been provided if you wish to etch your own board for the laser unit, and a parts-placement diagram is shown in Fig. 13. If you wish, you can certainly install the circuit in any kind of housing that you like — ^you don't have to follow our unit exactly. Just make sure you follow the cir- cuitry and the precautions con- cerning the laser diode. The specifications for LI are de- scribed in the parts list. Position it as shown in the handle of the laser so that it can slide over the charging coil (L2). DO NOT in- stall the laser diode in the circuit at this time: install only its sock- et. The circuit must be checked and calibrated beforehand. Don't forget to build the "simulated laser diode" shown in Fig. 10, It is used later on for testing and cal- ibrating the laser system, with- out the fear of damaging the actual laser diode, A cylindrical plastic enclosure houses the board, the batteries, and the optics. After the board is finished and checked out, it slides inside the plastic tube and the leads for SI (the touch switch) are brought outside through two small holes. (Wait until we check out the board be- fore installing it in the tube.) TWo z s m no m to o 37 f^.' CO o o ir o < pieces of metal tape are used for the contacts. Tfie lens is secured at the end of another tube using an appropriately sized washer The lens assembly then slides in and out of the main tube, allow- ing you to focus the beam. The charger circuit can be built on a small piece of perfo- rated construction board and wired according to the schematic in Fig. 11. In the prototype, Q6 is heatsinked by attaching it to the surface of the metal cabinet. It must be insulated, so use a nylon screw and a mica washer to mount it (or use a separate heat- sink). Coils L2 and L3 are wound on a ferrite core (see parts list), then wrapped with tape. The as- PARTS LIST FOR THE CHARGER All resistors are H-watt, 5%, un- less otherwise noted. R7— 470 Ohms R8— 22,000 ohms R9— 10,000 ohms Capacitors 06— 1000 tJ,F, 16 volts, electrolytic C7— 0.047 txR 50 volts, Mylar Semiconductors D4-D7— 1N4001 diode LED2 — green light-emitting diode Q6— D40D5 or NTE210 NPN power transistor Other components L2, L3 — coils wound on ferrite core (core is 1-inch in length, y4-inch di- ameter) L2 is 10 turns #24 wire, L3 is 10 turns #30 wire. T1— 120/1 2-volt AC Step-down trans- former, 100 mA S2— SPST switch PL1— 3-wire line cord Miscellaneous: perforated con- struction board, 6-32xy2-inch nyion screw and nut with mica washer {to mount Q6 to case), 2'/s- inch plastic tube to fit over laser tube, metal cabinet (or use sepa- rate heatsink for Q6), line cord bushing, LED mounting bushing, double-sided tape, hardware, wire nuts, #24 vinyl wire, epoxy, etc. sembly is then centered in the charger tube and secured with epoxy filler (see Fig. 12). Figure 14 shows how the laser section and the charger go to- gether. If you don't follow the pro- totype exactly, simply follow Fig. 14 as a rough layout. Checkout First make sure you do not have the laser diode in the circuit at this time. Plug the charger o 1— I o LASER LIGHT EMISSIOIM FORWARD CURRENT FIG. 9— A LASER DIODE OPERATES similarly to a forward-biased diode. Tfie vertical axis corresponds to optical output while the horizontal axis is ttre forward diode current. Iqp is the operating current, and anything below Ijh will produce the effects of an LED. f?fSP- HEATSINK .■;:pd SIMULATED LASER DIODE FIG. 10— HERE'S THE SCHEMATIC of the hand-held laser. The laser diode (D3) consists of the laser-diode (LD)and photodiode (PD) sections. That allows monitoring of the output energy and produces the feedback necessary to control the circuit. PL1 T1 1M40(n *M (6)— RX OPTIONAL R8 ■ (SEE TEXT) 22k: C7 i Tip. }i_. FIG. 11— THE CHARGER SCHEMATIC, charging current is inductively coupled to the hand- held laser. into a grounded AC outlet and check for 12-14 volts DC at test point 7 on the charger sche- matic. Check to see that LED2 turns on when you close S2. Open up the lead at test point TP6 on the charger and check for a reading of 100—125 milliamps (assuming the batteries aren't al- ready charged). In rare cases, if the current is excessively high, a resistor (RX) may be required as shown in the schematic to limit it. If a scope is available you may 38 L2 AND L3 WRAPPED ON FERRITE CORE \mtr- ^^ USER SLIDES N HERE Q6HEA TO TS INKED CASE ORDERING INFORMATION A kit of all parts for the hand-held laser except the laser diode, heat- sink, and retaining hardware (# VRLa-LHK), is available for S39.50. The special aluminum heatsink and diode retainer with hardware (#HS3) is S9.50. The price for the Toshiba laser diode (TOLD 9200) is continually dropping, although it is currently S74.50. A kit of all parts tor the charger {#VRL2-CMK) is $34.50. A kit of parts for the entire system, including batteries and charger is $158.50. Contact Infor- mation Unlimited, P.O. Box 716, Amherst, NH 03031. FAX: 603-672-5406. Toll-free order line: 800-221-1705. RG. 12— THIS IS THE CHARGING UNIT; the amount of current coupled to it depends on how far the laser is inserted Into the charger. In the charger, more or less current is coupled to it. FIG. 13— PARTS-PLACEMENT DIAGRAM for the laser. Do not install the laser diode until everything has been thoroughly tested. FIG. 14— The laser section has LI built Inside the handle; it slides over L2 in the charger. 5'/! INCHES H THIS FOIL PATTERN for the hand-held laser can be used if you wish to etch your own board. want to verify an approximate This verifies proper operation of sine-wave shape of 25—30 volts the charger, peak to pealc at a frequency of Connect an ammeter in series 250-300 kHz at test point TP8. virlth test point 1 on the laser. Slide coil LI of the laser over the ferrite core of L2 on the charger. Check for a current reading of 10—25 mill lamps and that the charge indicator (LEDl) is lit. The laser may be positioned in the charger socket for either a fast charge of 20 milli- amps at a 6—8 hour rate, or the recommended 10 milliamps at a s m CO O 39 CO o O or O UJ □ < DC 14 hour rate. Monitor the charg- ing current as you shde the laser in and out of the charger. Make sure that the batteries are fully charged before you pro- ceed with the following. Remove the laser from the charger. Note that the current goes to zero and LEDl goes out. Check on the lowest meter range; any current flowing into the circuit above a fraction of a microamp will cause premature discharging of the batteries. Check for defective components, flux paths, exces- sive moisture, etc if any current is detected in this step. Using the negative lead of B4 as a ground point, check for 5.6 volts at test point TP2. Adjust R6 to a maximum value (fully coun- ter-clockwise in our layout). Short out the touch-switch leads and note a current of 10—15 milH- amps. Remove the short and bridge the leads with dampened fingers; the current flow should be slightly less than the previous reading. This verifies the control circuit. If you haven't yet built the sim- ulated laser diode (shown in Fig. 10), do so now, and insert it into the circuit. Short out the touch switch and note a current of 75-85 milliamps. The LED should be glowing brightly. Ad- Just R6 in a clockwise direction to its midpoint and note the cur- rent increasing to over 100 mA. Check for a smooth control, as any jumps can spell disaster, es- pecially at the end of the potenti- ometer travel. Short the pho- totransistor section of test laser diode with a 470-ohm resistor to ground. You should note that the current increases further. The current will also increase if you interrupt the optical link be- tween the phototransistor and the LED. That verifies that the feedback circuit is operating properly CAUTION; Re-adjust R6 back to maximum resistance (fully CCW). As a reminder, ad- justment of R6 must be done with the batteries fully charged. Remove the touch-switch short. With a metal screwdriver, short out all pins of the laser-di- ode socket. Do not go any further if you suspect a high-static elec- trical condition. Wait for a damp day or use a humidifier or vapor- izer in your work area. Make sure the touch-switch leads are sepa- Applications and Notes Reprinied with pemilssion from T&^iba's TOLD9200-series applicalion guide An Example of Driving Circuit forTOLD9200 iTJO — ♦ Note: • Use the Laser diode after attaching t| to a heat sfnK. Use a larger heat sink during iha evaluatbn stage of decidirtg I he operating condilion. A copper or aluminym heat sink is recommended. • Set the vanable resistance VR {50k5!!i for its maximum value, Ehen turn a piTuver supply on. And regulate VR io adiusl optical output power. • When adjusting Itie opiical output power monitoi both the drive cun-ent and the optical outpul power, never exceed Ihe maximum optical output power raling. To monitor the optical oulput powef, use an opitcal power meter or a calibraled photodiode \hs\ has a large active area. In case of using the above driving circuit, the heat sink will have positive potenllgl • An Exaniple of the Design of a Heat Sink The relationship among the case temperature Tc, ambient tempefature Tg, and the thermal resistance of the heal sink 0t is shown in the following simplified equation: 5+ ft:) Heal &ink (Cu « All Rg^ Heat smk size and thermal resbtance {^t) "' ^ lop X Vw i's; Thermal resJslance of insuJatof sheet Oc'. Conlact thermal resislance Example: in the case of Tc=50PC T.^^^^a lop^lOOmA, Vop=ZS^. Os=G (no insufatof sheet), ^^sS^C/W. from the above equation: 9t ^ 50-45 0.1 X 2.5 8 = 12«C/W r I Heat sink thermal resistance must be t2='C/W or less. From the figure on the right, Ihe surface area of the alumi- num heal sink—assuming it is 2mm thick— musi be 25cm* in order lo obtain a thermal resistance ol v/"CMi or less. _ 4 '"^^ % imm ' 1 1 Coppef PfalB Sn. i 1 trm ■^ h? Wrh- 1.'' ^ ^- Ts "■ ^ i ^ 1 ' • 1 , _. ' "~ — -- 3i> S? 100 Radiator tf» {cm'l IMPORTANT NOTICES The circuit examples illustrated herein are pfesenled only as a guide ior the performances of the applJcetbns of our products. Keep in mind that no responsitjllity is assumed tjy TOSHiBA lor its use, nor for any infrmgements of patents or other righls o( Ihe third parties which may resuil from its use; and thai no license is granted tjy irnplication or other- wise under any patent riphls o( TOSHIBA. rated and that the meter reads zero current. Carefully insert the diode into the socket. Bridge the switch with your finger and note the laser diode lighting and a meter current of 70-80 milliamps. The laser diode should be lasing at this level. Short out the touch switch and note slightly higher current. At this point your laser is pro- ducing about 0.5 to 0.7 milliwat- ts- — so you might want to stop here. However, the actual laser- diode current is the meter read- ing [70-80 mA) minus the 10-20 milliamps at the touch-switch leads, which is still well below the allowed maximum. So it is possi- ble to get more power out of the laser diode. However, if you do de- cide lo challenge Murphy's laws, the next step should be done with a laser power meter. That's be- cause the output level is critical when adjusting for maximum. We used a Metrologic model number 45-540 laser power meter. Couple the head of the power meter to the laser diode and set it for the 20-milliwatts range. Use a piece of clay for temporarily se- curing them together. Short out the touch switch and note a continued on page 95 40 fiUILD YOUR OWN PORTflftlf 146-Htiz QUAD ANT€KKA ■:misXif LINTON G. ROBERTSON, KJ6EF Build this portable 2-meter quad antenna. It offers plenty of punch to the pound for your next Field Day adventure. IF YOU'RE AN AVTD VHF HILL-TOPPER. or just thinking about becoming a "ham", you'll be interested in this inexpensive and easy-to- build antenna for the 2-meter band. Join in the spirit of public- service by taking this light, por- table quad antenna into the great outdoors on Field Day, an annual event held every June. On Field Day, amateur radio operators take their equipment into the field and, using power generated at the operating site, test it to pre- pare for their response in the event of a disaster Our portable quad antenna weighs only two and three quarter pounds, and has good gain compared to a four-element Yagi. Assembly of the antenna is made simple by the use of PVC pipes and cross- tees. All the ma- terials you need for this project are available at your local home- improvement center, and they are quite inexpensive. The authors antenna cost about fifteen dol- lars, including the coaxial matching section. No exotic tun- ing devices are required; all you need is a simple SWR (standing wave ratio) meter Figure 1 shows a view of the antenna with the spreader elements taken apart, ready to be transported. Construction The quad antenna consists of four element spreaders (reflector. driver, and two director sec- tions), four boom sections, a boom support and mast, five cross-tees and two support lines. The spreaders are four legs that hold the actual elements. The spreader elements should be as- sembled first. The boom support and boom sections can be as- sembled later. Figure 2 shows how all sections are connected. Cross-tees CI through C4 are used in the construction of the four element spreaders. Cross- tee C5 is used for final assembly. Four spreader legs are cemented into the four openings of cross- tees CI through C4. The legs, which hold the antenna ele- ments, should be cut following § m m CD to O 41 SPREADER DIMENSIONS FIG. 1— THE ENTIRE ASSEMBLY BREAKS down and sets up in about five minutes tor easy portability. Extremely light, it can be pacl for you, ready to use. They're all in the catalog, along with a lot of other "solid gold" ideas. See your nearest Authorized Pomona I)istributor or contact POMONA ELECTRONICS. 1500 E. Ninth St., PO Box 2767, Pomona, CA 91769 FAX (714) 629-3317 (714) 623-3463 !TT Pomona AN rrr emc worldwide company Discover our strengths. CIRCLE 101 ON FHEE INFORMATION CARD RG. 6— A REAR VIEW SHOWS ROUTING OF THE coaxial matching line, the sag support tie points and the wooden dowel support for the antenna feedllne. nector shown in Fig. 7-a. That type of bulkhead connector pro- vides a maximum adhesion sui- face for the silicone sealing step. Connect the coaxial matching line with a length of RG58/U ca- ble and a PL-259 plug, shown in Fig. 7-b. Use a Voltage Standing-Wave Ratio (VSWR) meter to help you tune the antenna. The VS'WR is an important tool in matching impedances of a transmission system. A VSWR reading, usually called simply the SWR, indicates the ratio of the load impedance to the feedpoint impedance. For maximum power transfer to oc- cur, the feedpoint impedance of the antenna should closely match that of the transmission line. If those impedances are mis- matched, some unabsorbed power is reflected back down the transmission line. Not only is that inefficietit, it can damage a transmitters output stage. For proper tuning of the anten- na, the SWR meter should mea- sure below 1.5. If not. desolder the 50-239 connector from the matching coaxial cable, trim a quarter of an inch from the cen- ter conductor and the braid, re- solder and measure again. Re- peat that process untilthe SWR reaches at least 1.5. If that cannot PLUG PL-ZM RECEITM;LFS0-!39 FIG. 7— A STANDARD PLUG AND RECEP- TACLE used to mate two coaxial cable sections; (a) Is a PL-259 plug and (b) Is an SO-239 receptacle. be achieved. youVe done some- thing wrong, probably with the driver spreader dimensions. The models the author has built come down to 1.1 at 146 MHz, and rise to 1.5 at the band edges of 144 MHz and 148 MHz. Also, you might not want to push your luck in trimming the antenna past about 1.4 or 1.3. IftheSWRsud^ denly rises after an adjustment, you've probably passed the null. You should still be able to get the SWR reading down very low. After you've gotten the SWR down to an acceptable level, seal the feedline connector with sil- icone cement for a good, weather- tight seal. Apply a heavy amount of silicone so that it completely covers the exposed area from the SO-239 connector to past the edge of the skinned coaxial cable,. . PARTS LIST Schedule 125 PVC pipe— 20 feet, Vz- inch in diameter PVC cross tees — 5 #14 or #16 gauge wire — 11 yards Two-part quick-drying epoxy— 1 tube RG59/U coaxial cable — 1 yard SO-239 bulkhead connector— 1 PL259 plug— 1 %-inch wooden dowel— 6 inches Nylon cord — 8 feet yj" PVC couplers— 6 Silicone sealing compound, or RTV— 1 tube Eiectrical tape — 1 roll Allow the feedline connector to diy for one day. After the connector is thor- oughly dried and cured, feed the antenna with the RG58/U cable. The cable length should be rea- sonably short — 50-foot runs are not a good idea. The antenna works well in the field. When tested over a one- hundred and fifty mile distance, strengths of S-9 were reported with as little as 3 watts from a hilltop locale. When we turned up the power on the quad to 30 watts, the receiving station oper- ator said he'd send us a bill for a new S- meter! Apparently, the quad antenna does have good gain. 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There is no extra charge— it's yours to use while you study at home and on the job after you complete your course! Earn Your D^ree To Become A Professional In Electronics! Every CIE course you take earns you credit towards the completion of your Associate in Applied Science DegrBe, so you can work towards your d^ree in stages. And CIE Is the only school that awards you for fast study, which can save you thousands of dollars in obtaining the same electronics education found in four-year Bachelor's Degree programs! Write for details today! Send For Your Catalog Today! j CIE World Heattquarters Cleveland Institute of Electronics, lie. 1776 East 17th St.. Cleveland, Ohio 44114 n YES J Please send me yt*ur independent study catalog (For your cmvenlence. CIE wl! tave a representative contact you— (here *s no obligatm) Apt# Area Code' Phone No Ched< box for G.I. Bill bulletin on educational [jenefits: Q Veteran a Active Duty Mail This Coupon Today! 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Never in history have so many people been able to communicate with so many others at such a low cost. But the price for being able to reach out and touch almost anyone also in- cludes the opportunity for almost anyone to be touched, by anyone else with a phone. But the fact is, most people would rather not be called by strangers. One system that appears to of- fer promise is "Caller ID," which provides the called party with a read-out of the caller's telephone number before the phone is an- swered. Customer response to this service is reportedly very good. The problem is, of course, that the system screens only tele- phones, not callers. If a call is made by an "authorized caller" from another telephone, the called party will not recognize the number and might reject the call. The cost for the service is about $100 to start, with a monthly ser- vice fee of around $6. The real solution to the prob- lem of screening unwanted tele- phone calls must be one that screens callers, not numbers. It must include a security system that no accidental access such as wrong numbers or sequentially dialed numbers can breach. And the user should be spared the in- trusion of having to screen his or ow you can unwanted phone calls from reaching you—onfy an fl authorized caller will be able to ring your phone! H G. KOLLER her own calls, which Is the case ^\vfth an answering machine or ^Caller ID. The real solution sshould Inlercept incoming calls ■and silently and automatically ;screen them. When a calier is cleared, then the phone rings. -M . The CallScreen does all of th^ [and more. It's easy to use, easy to ! Install, easy to build, and rela- tively inexpensive. Wliat's more. ; the unit can also send fax or [ modem calls directly to specified 'device. If this no-nonsense ap- i proach to call screening appeals to you and seems worthwhile, then read on because the solu- tion is herel Operation The CallScreen connects to the phone line at the point where the line enters the building, and the "slave" phones connect to the CallScreen. The unit features "Limited Screen" and "'Full Screen" modes, which can be se- lected by toggling one of two pushbuttons on the cabinet; the other button toggles "Screen On"/"Screen Off." However, the easiest way to select screen modes is with the "*" and "#" keys on any phone connected to the CallScreen. Pressing the "*" key will alternately select Screen on/Screen Off. Actually, one version of the CallScreen doesn't even have the pushbuttons — you must use a phone to change modes. When- ever a transition to Screen On is made, a momentary tone is heard through the handset. The "#" key selects Limited Screen/Full Screen, with the transition to Full Screen producing the tone. LED indicators on the cab inet in- j. dicate the current screening g mode, regardless of which meth- g od is used for selection. Should a w power failure occur, the Call- S Screen bypasses itself so that ^ normal telephone service is pro- o 49 w o z o ir UJ _i LU o □ < vided. We'll now describe the op- eration of the CallScreen in Limited Screen mode. When the unit detects ring cur- rent on the telephone line, the line is taken off-hook and a short tone burst is injected into the phone line, to signal the caller to enter a three-digit access code. The caller then has approximate- ly seven seconds to enter a three- digit number sequence that must match either of two codes (a primary code and a secondary code) set by the user. Each three-digit code is set via a set of DIP switches. Allowable codes include digits "1" to "9." The digit "0" is reserved for code- entry errors. If the caller enters incorrect digits; a zero may be en- tered causing the CallScreen to erase the previous digits and pre- pare for re-entry. When a correctly entered pri- mary code is detected, the Call- Screen begins ringing any tele- phone connected to its output jack with a cadence of two short rings and a pause. The secondary code cadence Is three short rings and a pause. The CallScreen owner now knows, by the type of ring, that the call has been screened and has some idea of the caller's identity {family or friends for instance). If neither code is entered, a standard ring is generated, which continues until any phone is picked up, or the caller hangs up. Should the unit be set in the Full Screen mode, the completion of the seven-second entry interval, with no proper code entered, results in the line going back on-hook, dis- connecting the caller. A call-routing adapter (CRA) al- lows operation with telephones and a choice of either an answer- ing machine or a modem/fac- simile machine. When the CRA is set for "ans mach," any un- screened calls will be routed to an output jack to which an answer- ing machine may be connected. When the CRA is set for "comp/ FAX," all primary code calls and unscreened calls (or primary code calls only if the CallScreen is set for Full Screen) will be routed to the protected phone(s), while secondary code calls will be routed to the computer modem or facsimile machine. If the user would rather sub- stitute other telephones for the answering machine/modem/fac- simile machine in order to con- trol where in the building a phone will ring, full answer (off- hook) and connect recognition is provided even for telephones that are not ringing. That allows any protected phone to "answer" a ring even if the ring was being routed to another phone. When the CRA is switched off. all processed calls are passed to both CRA output jacks. Outgoing calls are unaffected by the CRA regardless of its on/off status. The CallScreen consists of five major circuits: Phone Line Inter- face, Decoder, Control and Reset Logic, Ringer, and Slave Tele- phone(s) Interface. We'll describe each section in detail. Phone line interface Figure 1 shows the schematic of the CallScreen. Incoming tele- phone calls are detected by 1C7, a Texas Instruments TCM1520 ring detector IC, which, along with the other circuitry, is pro- tected from over-voltages by sur- ge suppressor R8. Capacitor CI 2 blocks DC voltage from entering 1C7. and Rll limits ring current so that IC7 operates over a typical 40-150 volts RMS ring-voltage range. The incoming ring voltage charges C13 which brings pin 4 of 1C7 high with respect to pin 3. After less than one full ring, the current from pin 4 turns on the LED inside ICIO, which turns on the phototransistor That, in turn, puts a low on pin 2 of nor gate IC3-a. Pin 1 of IC3-a is connected to the Master Reset line which is normally low, so when pin 2 goes low pin 3 goes high and pin 4 goes low. When the first ring in- terval has ended, the phototran- sistor in ICIO switches off. But, since IC3-b pin 4 is low and is connected through R19 back to pin 2, pin 3 remains latched high regardless of the state of IC 10. As long as pin 3 is high, a forward bias current, limited by R22, flows through the base-emitter junction of Qt. turning Ql on and energizing RYl, which takes the phone line off-hook. It takes about 100 milhseconds for RYl to be activated after pin 3 of IC3-a latches high. That allows multi- ple CallScreen units connected to the same telephone line to latch befoi-e any of them actually "an- swer" the call. The time delay is generated by a ramp voltage across C18 following the latch up of IC3-apin3. When RYl's contacts close, they provide a DC path across the telephone line through BR2 and R6. The resulting I)C current through R6 signals an "off-hook" condition to the central office, which then removes the ring volt- age and connects the calling par- ty to the line. Bridge rectifier BR2 ensures that, regardless of the phone4ine polarity, the end of R6 that's connected to C5 is always positive with respect to the other end. If, while the CallScreen is off-hook, any other telephone on the same line is lifted, the voltage across R6 will decrease due to the additional load placed across the line.- That voltage change is coupled through C5 as a negative pulse that appears on 1C8 pin 2, mo- mentarily illuminating the inter- nal LED. The 1C8 phototran- sistors then conduct, placing a brief low on pins 12 and 13 of lC27-d. which is part of the Con- trol and Reset logic. That sends a reset pulse to pin 1 of IC27-a, which, with IC27-b, normally passes reset pulses to IC3-a pin 1. to release the off-hook latch. However, during the cue interval pin 2 of IC27-a receives a logic low, which disables the passage of reset pulses during this time. That allows any phone-line tran- sients, that could trigger the off- hook detection circuit at the mo- ment the CallScreen raises an off- ho ok, to delay before enabling the Master Reset line. The cue timer interval begins just before the CallScreen goes off-hook, and continues for approximately 1 second. Diode D3 protects the LED inside 1C8 from any reverse voltage transients that may be on the telephone line. The momentary negative-go- ing pulse develops at IC27-d pins 12 and 13 whenever a remote phone is raised off-hook appears inverted (as a momentary high) at pin 1 of lC3-a. That pulse will unlatch IC3-a/lC3-b, releasing RYl, resetting the CallScreen, which goes back on-hook to await another call. Audio is coupled to the phone line through transformer T2, which is AC -coupled to the line at all times via CU so that signaling 50 WMS CWK i CUE TONES 03 INUtrt FULL SCREEN ON TPfl TFS FIG. 1— SCHEMATIC OF THE CALLSCREEN. It can prevent unauthorized caliers from wasting your time with "junk" calls. 2 0661 b39W3AON CALLSCREEN PARTS All resistors are V^-watt, 5%, un- less otherwise noted. R1, RIO, R46, R57, R65, R68— 1 megohm R2, R5, R7, R17-R19, R23, R26, R32, R33, R36-R42, R52-R55, R58, R60. R63, R67, R70, R7&- 10,000 Ohms R3, R27— 560 ohms R4, R29, R71^7,000 ohms R6— 560 Ohms, '/a-watt R8 — metal-oxide varistor surge-sup- pressor, 130 VRMS, 15 joules R9-not used R11, R12— 2200 ohms R13~R16, R20, R24, R25, R30, R31, R34, R45, R61— 100,000 ohms R21— 680,000 ohms R22, R50 — 4700 ohms R28— 680 ohms R35— 51,000 Ohms R43, R44— 180 ohms R47-R49— 200,000 ohms R51— 2000 ohms, potentiometer R56— 390,000 ohms R59~100 Ohms R62, R74— 470 ohms R64— 150 ohms, '/2-watt R66~32,000 Ohms, 1% R69— 33,000 ohms R72— 220 ohms R73— 10 ohms Capacitors CI , C32, C34, C35, C40, C48, C58— 10 n-F, 10 volts, radial electrolytic C2, C3, C16, C17, C19, C20, C23, C25, C28-C31, C39, C47, C56— 0.02 piF, 20 voits, ceramic disc C4, CIO, C21, 052—22 jjlF, 16 volts, radial electrolytic C5, CI 5, C22, C24, C26, 033, C49, 050, 051. 054, 055, 057— 0.1 fiF, 20 volts, ceramic disc C6-C9— rsot used C11— 0.33 tiR 250 volts, polypropylene 012—0.47 \x.F, 250 volts. polypropylene 013— 10 jj,F, 50 volts, axial electrolytic C14— 2200 JJ.F 20 volts, radial electrolytic 018—100 (X.F, 10 volts, radial electrolytic 027 — 4.7 M-R 10 volts, non-polarized axial electrolytic 036—0.039 n-R 20 volts, ceramic disc C37— 0.01 txR 20 volts, ceramic disc 038, 053—0.05 n.R 20 volts, ceramic disc C41, C45-^70 [iF, 10 volts, radial electrolytic 042, 046—0.22 jjlR 50 volts, polyester 043 — 1 M-R 35 volts, tantalum 044 — 4700 fiR 16 volts, radial electrolytic Semiconductors 101— LM1458 dual op-amp 102, IC25— LM741 op-amp 103— MC4001 quad NOR gate 104, I012-IC14, IC22— MC4081 quad AND gate IC5— SSI 202 DTMF receiver (Silicon Systems, Inc.) iC6— MO4028 BOD-to-decimal converter 107— TOM1520 ring detector (Texas instruments) IC8. IC21— 4N33 Darlington opto-coupler 109— MC4071 quad OR gate 1010, IC28— MCT-2 transistor opto-coupier IC11, IC20, IC24, 1027— M04011 quad NAND gate 1018— MC4013 dual D-type flip-flop IC15-IC17, 1023— M04017 decade counter IC19— MC780S 5-volt regulator IC26— LIV1383 7-watt power amplifier D1, D2, D35, D40— IN5231 5.1 -volt Zener diode D3-D10, D12-D18, D20-D32 D36-D39, D41— 1N914diode D11, D19, D33, D34— not used LED1, LED2— red light-emitting diode 01^4— 2N4401 NPN transistor BR1—50-PIV1,5-amp bridge rectifier BR2, BR3— 100-PIV, 0,5-amp bridge rectifier Other components T1— 120/1 2VA0 950 mA power transformer T2— 600/600-ohm telephone line coupling transformer T3— 8/8K ohm 10-watt matching transformer (use 8-ohm and 0.625- watt taps on 70-volt line transformer) XTAL1— 3.58-MHz colorburst crystal SI, S2— SPST momentary pushbutton switch S3-S8— 9-position DIP switch RY1— SPST N.O, miniature relay 5- volt, 70-ohm coil (or nearly any other 5-volt miniature relay) RY2— DPDT miniature relay, 12-vol1, 290-ohm coil (or with a coil be- tween 260-400 ohms) Miscellaneous: PC boards, cabinet, linecord, telephone wire, stranded wire, solder, hardware, etc. to o o UJ _J Hi o to and from CallScreen can occur regardless of the hook status. That allows you to change screen- ing modes using the "*" and "#" keys of slave phones while the CallScreen remains on-hook. Any voltages on T2's secondary are clamped by Dl and D2 to ap- proximately 5 volts while audio is coupled through CIO. Op-amp ICl-a, which operates at unity gain, drives ring-back and cue-tone audio through R3. A coupling network to pin 5 of ICl, made up of R27, R28. and C52 approximately mirrors R3, CIO, and the secondary imped- ance of T2. Therefore, the output signal from ICl-a appears equally across the differential inputs of ICf-b, producing very little out- put signal on pin 7. However, sig- nals that are input from the phone line to pin 6 have a very small in-phase component ap- pearing on the non-inverting in- put of ICl-b, so they appear at pin 7 amplified by a factor of approxi- mately four, as set by R2 and R4. The attenuation of phone-line input signals appearing on ICl-b pin 5 occurs by the voltage divid- ing of R3 and the very low output impedance of ICl-a. The output of ICl-b is connected through equalization network R5, C2, and C3 to dual-tone multi-fre- quency (DTMF) receiver IC5. In- puts to ICl are biased to 'A ofV^f, by Rl, and CI provides AC de- coupling of the bias source. Decoder DTMF tones are coupled from the phone line to the audio input (pin 9) of DTMF receiver 1C5, a Silicon Systems SSI 202 (or Sier- ra Semiconductor SSI 202) chip set up for.BCD output on pins 1, 16. 17. 18. The chip contains Its own clock whose frequency is set by XTALl. Normally, pin 15 (clear dv — clear detection valid) is logic low and pin 3 (enable) is logic high. Under those condi- tions, valid DTMF tone pairs, while being received from the telephone line, produce a BCD output and simultaneously raise the DV output (pin 14) to logic high. The data outputs from 1C5 are connected to BCD-to-decimal converter 1C6. Pull-down re- sistors R13— R16 ensure a solid logic low at the inputs to IC6. De- cade outputs from IC6 are con- nected to two sets of three nine- position DIP switches which are used to select two three-digit ac- cess codes. Both inputs of and gate IC12-d bridge the BCD lines to detect the presence of digit "0. " Likewise, IC14-a and 1C14-C de- tect the "#" and "*" respectively. 52 I f- When the CallScreen "answers" a call, the logic high from IC3-b pin 4, which holds the decoder circuitry inoperative until the CallScreen is off-hook, goes low and removes the reset from de- cade counters 1C15, IC16, and IC17 through D41. At this time, IC15, IC16, and IC17 all have their QO outputs at logic high, and are enabled to begin count- ing. Because reset signals are di- ode-coupled, R75 is used to ensure a solid logic low on the decade counter reset line in the absence of reset logic levels. At all other times, the reset high to the decoder circuit prevents the tone-decoded ringing of slave phones, should the first three digits of a number dialed from a non-protected phone coinciden- tally contain a valid three-digit code. ORDERING INFORMATION Note: The following is available from Electronic Control Systems, R.D. 2 Box 3308, Wemersviile, PA 19565. Set of two double-sided, plated-through PC boards, $39.95 (add $2.00 postage and handling); complete kit including PC boards and all parts except the cabinet, $158,000 (add $2.50 postage and handling). PA residents add 6% to all orders. Check or money order only. For the following discussion of call decoding, we will assume a primary access code of 3-4-5, as shown by the DIP-switch settings on the schematic. Since IC15's QO output (pin 3) is high, pri- mary and secondary code-enable gates IC12-a and lC13-a are en- abled. The first DTMF tone pair received will be a three, and will appear as a logic high at switch position three of all DIP switches. Primary code switch digit "A" is in position three, so therefore the momentary logic high produced during the presence of DTMF-3 is passed through to IC12-a. When IC12-a is enabled, its output goes high and increments counter 1C16 through D12. and 5-ins time-delay network R29-C54. Meanwhile, when the DTMF re- ceiver is detecting the valid tone pair representing the number 3, the Dv line (IC5 pin 14) goes high. When the tones disappear, dv goes low, incrementing counter IC15 such that QO (pin 3] goes low and Ql (pin 2) goes high to enable ICJ2-b and lC13-b for re- ception of the next digit. The next digit will be a 4, and the logic high produced by it will pass through any DIP switches in position 4, incrementing coun- ters IC16 and/or 1C17 if the switch in position 4 is for digit B. In this example, 1C16 will be in- cremented and two correct digits for the primary code will have been counted. Again, the transi- tion of Dv from logic high to low Increments counter IC15 by one count, now enabling IC12-c and 1C13-C. Next, a third DTMF tone pair is received representing a 5. It passes through 1CI2-C and D14 incrementing IC16 again, now producing a logic high on Q3 (pin 7) of ICI6. As soon as three cor- rect digits are counted by either counter, the ringer circuitry is ac- tivated to begin the ring. Whenever the CallScreen rings the slave phones, pin I of lC20-a is at logic high through either D8, D9. or DIO. The logic high is also coupled to ICIl-a (which is connected as an inverter) whose output (pin 3) is then a logic low. Through R31. that low disables DTMF-receiver IC5 via pin 3 (enable), making the CallScreen ignore any further DTMF input. The detection of a correct code, by the Q3 output being high on either IC16 or IC17, is also cou- pled to the reset logic through NOR gate IC3-d pins 12 and 13. When either input to IC3-d goes high, its output goes low, disab- ling any control action resulting from the seven-second time-out of the code-entry interval timer IC3-C. Counter ICI5 accumulates the total number of digits input; when three have been entered, the Q3 output (pin 7) goes high. The Q3 high output is connected to IC5 pin 15 (clear Dv), freezing the counter at three by disabling the DV output on IC5. The only valid tone pair that the Call- Screen can now recognize to use is digit "0." Tbne pairs 1-9 are ignored since none of the gates are enabled. The "*" and "#" tones for remote mode-selection are also ignored because the re- mote-select gates are enabled only when one of the slave phones is off-hook. 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Stargau convener J95 175 Panaioflic converter. $99. $7^ 30 Days Money Back Guarantee Free 16 page Catalog Visa, KA/C, COD or send money order to: US Cable TV Inc. dcplkreu 41D0 N.Powerline Sd., Suite F'4 Pompaco Beacli, FL 33073 1-800-445-9285 For Our Record I, the UFidersigned, 6o hereby declare under penalty of per- jury that all prxluctA purchased, now and in the future, will oary be qmu on CaWe TV lyitema with proper authorization frOTB local ot^cials or cable company ofliciali in accordance wlh all applicable federal and state laws. FEDERAL AND VARIOUS STATE LAWS PROVIDE FOR SUBSTAhmAL CRIMINALANDCrVILPE N ALTl ES FOR UN AUTHORI ZED USE. Date: Signed: No Florida Sales! If the caller enters "0"' now, or at any time during the code dialing sequence, both inputs of IC12-d go high from IC5's BCD lines, and a logic high appears at pin 11 of lC12-d. That high is coupled through D5 to the reset (pin 15) of each of the decoding counters 1C15, IC16, and IC17. Since the reset is blocked by reverse-biased D41, it does not affect any other circuitry, and the seven-second interval timer continues to run. Still, if the three digits counted by 1C15 represent a valid code, then the entire DTMF receiver is shut down as discussed above, via ICS's ENABLE input. Both flip-flop sections of 1C18 are used for screen-mode selec- tion latching. Local selection is made via push buttons SI and S2. A momentary closure of SI raises a momentary logic high on CLOCK pin U of IC18. That trans- fers the logic state of data pin 9 to the Q output pin 13. Since g (pin 12) is connected directly to pin 9, Q and g both change state and remain latched upon each mo- mentary closure of SI, The q and g outputs are used to control cir- cuitry in the reset logic to place the CallScreen in either Full- Screen or Limited-Screen mode, so the mode changes occur in a toggle fashion using SI. When g (pin 13) is high, the Pull-Screen mode is active and Q3 is turned on lighting LED2. The selection of Screen On/ Screen Off is made independent of Full- or Limited-Screen selec- tion. However, IC18-a is toggled by 32 in a similar manner as lC18-b. Screen-On status is indi- cated by LEDl, where R43 and R44 are current-limiting re- sistors. Transistors Q2 and Q3 are connected in a series ar- rangement such that LEDl will be turned on any time the screen mode is "on." However, LED2 cannot be turned on by Q3 unless Q2 is also on. Resistors R38 and R39 ensure a solid logic-low at the clock inputs of IC18 in the absence of positive pulses. Capacitors C30 and C31 prevent the outputs of 81 and S2 from bouncing, which would produce multiple transfers of the Oip-flops. The connection of reset pins 4 and 10 together through 032 to -(- 5V and through R40 to ground causes both flip-flops to be reset when- ever power is applied. That en- sures that the operating mode will always initialize to Screen Off/Limited Screen in case of a power failure. The MASTER RESET line is con- stantly held high by IC18-a from g (pin 2) through or gates IC9-C and IC9-b whenever the Call- Screen is in the Screen Off mode. Limited/Rill Screen is controlled by iC18-b by enabling/disabling AND gates IC4-a and lC4-b in the reset logic. Remote mode selection can be made through any Touch -Tone type telephone connected as a slave. The "*" and "#'* BCD out- puts from IC5 are detected by IC14. When IC5 receives a "*." Dl, D2, and D8 (pins 1. 18, and 16) go high. That places a logic high on pins 8 and 9 of IC14-C and on pin 2 of IC14-a. Pin I of IC14-a is con- nected to remote mode-change timer lC9-d, which holds a logic high on pin 1 of lC14-a for 7 sec- onds after any slave phone goes off-hook. Such a combination of logic levels causes pins 3 and 10 to go high, causing pin 4 to go high, which toggles the state of IC18-a through' D21. When IC5 receives a "#," D4 and D8 (pins 16 and 17) go high. That places a logic high on pin 2 of IC14-a and pin 13 of IC14-d, If pin 1 of lC14-a is Edso high from IC9-d, pin 3 of IC14-a will go high, toggling IC18-b through D20. Control and reset logic There are two reset conditions used by the CallScreen. One is a constant logic high on the MASTER KESET line which disables the off-hook latch (IC3-a and IC3- b), effectively shutting down the unit. The two signals that can hold the MASTER reset line high are slave-off-hook {IC9-c pin 9) Emd screen off (IC9-C pin 8). The other reset condition occurs as an intermittent logic high deliv- ered to the MASTER RESET line when the CallScreen is off-hook and is ending the process of screening a call. Any one of the following inputs wil) result in a momentary reset high: a) Code-entry Interval time-out when the CallScreen is in the Pull-Screen mode and successful code entry is not made. b) The calling telephone transi- tions to on-hook and local loop CIRCLE 187 ON FREE INFORMATION CARD current momentarily drops. c) Any other telephone on the CallScreen telephone line (local loop) transitions to off- hook. During the one-second cue- tone interval that occurs while the CallScreen goes off-hook for an incoming call, pin 10 of ICll-c I ■ provides the enable gate (IC27-a ' ' and lC27-b) with a logic low on pin 2. That prevents any reset signals from reaching the off- ' ' ^ hook latch during the off-hook '. time when line switching tran- sients could trip the remote off- hook detector. The code-entry interval timer . , {IC3-C) is initiated when pin 4 of ' ' lC3-b goes low. Pin 9 of IC3-c is , normally low while pin 8 is nor- 7*— mally high. When pin 5 of lC3-b goes high, pin 9 eiIso goes high through C4. At the same time, pins 4 and 8 go low so that pin 10 remains low. Any transients that might disturb the transition of ' . input states to lC3-c are filtered by R20 and C16. As C4 charges, the voltage across R21 decreases; when it falls below approximately 1.5 volts, pin 9 sees a logic low and, since pin 8 is also low, pin 10 now goes high. That represents the end of the seven-second code-en- try interval. The output of 1C3-C is coupled through RC filter R23-C17 to and gates lC4-a (Limited -Screen log- ic) and IC4-b (Full-Screen logic). When the CallScreen is set to ;• . Limited Screen, IC4-a is enabled through pin 1 from pin 12 (g) of IC18-b. The lC4-a output is cou- pled to AND gate lC4-d. Gates 1C4- c and IC4-d are normally enabled through lC3-d, whose inputs come from the number of correct digits that enter counters IC16 and IC 17. When either a primary or secondary code entry is cor- rect, either pin 12 or pin 13 of IC3-d will go high, placing pin 11 low and disabling both lC4-c and IC4-d. That prevents the genera- tion of a standard ring, or the trigger of a master reset after a seven-second time-out, when- • - ever a valid code is entered. If a valid code is not detected, the log- ' ic high produced by the seven- second time-out appears on pin • ■ 11 of IC4-d and is coupled to the ringer for generation of a stan- dard ring to indicate an un- screened call. If IC4-b is enabled for Full- Screen operation (pin 13 of IC18- b is high), the seven-second time- out produces a logic high on 1C4- b pin 4. If a valid code has not been received, that high appears on pin 10 and is passed through IC9-a and lC9-b to the master re- set line, releasing the off-hook latch. The MASTER RESET Is used only to enable or disable the off-hook latch. The master reset will also disconnect the CallScreen from the phone line whenever the re- mote off-hook detector (IC8 pin 5) couples a momentary low to lC27-d. That logic level is inver- ted by lC27-d, which then ap- pears, through various gates, on the master reset line. Pin 2 of IC27-a receives a low from ICll-c pin 10 during the cue interval. That prevents the resetting of the off-hook latch during the cue in- terval when the CallScreen is go- ing off-hook and the loop current is changing. There are two conditions that will hold the master reset high indefinitely: pin 9 of IC9-c re- ceives a continuous high when- ever any slave phone is off-hook, and pin 8 receives a continuous high whenever the screen mode is off. Either of those conditions will hold the off-hook latch in- operative, disabling ring detec- tion and the decoder. A high on pin 10 of 1C9-C is inverted by IC 1 1- d and coupled to the base of Q4; that causes relay RY2 to drop out, connecting the slave phone(s) di- rectly to the telephone line, by- passing the CallScreen. The cue timer one-shot, made up of ICll-b and ICll-c. operates as a monostable multivibrator, triggerable by either positively or negatively transitioning logic lev- els. The outputs of the cue timer perform two functions during the timing interval: first, to turn on the 600-Hz cue-tone oscillator and, second, to disable the master reset line. The first func- tion is operated from ICll-b pin 4, which is normsilly low and goes high. The second is operated from ICll-c pin 10, which is nor- mally high and goes low. The cue timer one-shot mono- stable multivibrator is triggered by a high pulse through C20 to ICll-c pin 8 when the CallScreen goes off-hook; the other input to ICll-c is normally high. The cue ^?i'iyS'^"o!^ "^'^'S'^ €'€*JH^« SANYO RF Modufator #4-1164-031600 Si 7.85 Eb. 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CAPACITORS 100JMFDJ50 Volts 4.7MFD/250 Volls 10MFO/350 Volts IOaOMFD/200 Volts 68DIWFD/200 Volta 100MFD/200 Volta 4TMFD/&0 Volta 10MFD/2S Volta aoaMFO/2oa VoHs aOMFD/450 Volta Radial Radial Radial Snap-In Snap.|n Radial Radial Non Pdarizad Snap- In Axial 20 For $10.00 to For 5.50 10 For 7.50 S For 12.50 5 For 12.50 10 For 12.50 ID ForA.iO 10 For 5.00 5 For 12,60 10 For 19.90 popuuack Sharp Flyback Sharp Flyback Sharp Flyback Sharp Flyback Sanyo Flyback Sanyo Flyback Tripler Sarnsung Sarrsung Samsung FO003G FO003G F0ai4G F0015G FOOtOG FO260 F0192 523A/S26A FCC1415AL FCC2015AL 523/526A t19.9S Ea, 19.9S Ea. 19.95 Ea. 19.95 Ea. 19.95 Ea. 14.96 Ea. 14,95 Ea, 9,95 Ea. 19,95 Ea, 19,95 Ea, 9,95 Ea, ASK F OR OUR FREE CATALOG ! fcd^lELECTRONICS'^ 975 Jaymor Rd. Southampton, PA 18966 CALL TOLL FREE: 1-800-628-1118 m tjj m 3: CIRCLE 89 ON FREE INFORMATION CARD 55 timer is disabled by ICl 1-a when- ever the ringer is enabled and the CallScreen is ringing the slave phones. RC network R31-C24 de- lays the re-enabling of the cue timer when the ring-enable sig- nal returns to logic low. That de- lay allows any ring transients — that could develop should a slave phone transition off-hook at a moment when the instanta- neous ring voltage is high — to de- cay before re-enabling the cue timer. The cue timer must be dis- abled during a CallScreen-gener- aled ring, because of the high input impedance of the timer trigger circuits and their sen- sitivily to stray pickup from the high ring voltage. There are two other input trig- gers to the cue timer. Each input is capacitively coupled so that ei- ther input can produce momen- tary low levels on pin 5 of ICU-b, which is normally held high through R45. These inputs come from the screen-mode select flip- flops of 1C18. Whenever the mode transitions from Screen Off to Screen On, the reset level at pin 8 of 1C9 goes low. Before pin 8 goes low, C23 has no charge on it. The transition of pin 8 to low forward biases D7 allowing C23 to charge from the + 5 volt supply through R45. The initial charg- ing current causes a large mo- mentary voltage drop across R45 effectively reducing the voltage at pin 5 of ICll-b to logic low, trig- gering the cue timer to inject a tone into the telephone line. At the same time, D6 is either mo- mentarily reverse biased or has zero bias depending on the sta- tus of Limited/Full Screen selec- tion. That effectively presents a high impedance (lOOK set by R24). preventing swamping of the logic low pulse developed by C23/D7. When 1C9-C pin 8 transitions high (screen mode is being set to off), C23 is fully charged to -I-5V, and D7 is reverse-biased. Re- sistor R30 discharges C23 by bringing both of its terminals to a -I-5V potential. The transition from Limited to Full Screen also triggers the cue timer in a man- ner similar to that described CO o z o cr & Hi D < 56 Buy American AsIc about quantity discounts Model Shown: 5 10-SW-] lOOMHZ, SwitchableXl-XIO $36 * Complete range of monolithic & modular probes from 60MHz - 300 MHz. Available with read-out Feature. ■* Compatible with oil oscilloscopes. ■* Complete accessory pack (as shown). * Tek and HP users: try us and compare our high quality low cost probes! -^ Made in the U,S.A. "'' ' ' Call for Free catalog 1-800-87-PROBE Attention All Oscilloscope Users Try API Probes FREE for 30 days. We are so sure that our probes will meet or exceed your performance requirements that we will send qualified buyers a sample for a 30 day evaluation. Affer 30 days, either keep the probe and we will bill you, or simply return it to us. It's that easy. Avex Probes Inc. 1683 Winchester Road • P. (). Box 1026 Bensalem, PA 19020 Phone 215-638-3300 - Fax 215-638-9108 For More tnformation Circle 28 CIRCLE 196 ON FREE INFORMATION CAI^O above, but uses R24. C19, D6and R45. With the cue timer enabled (pin 9 of ICll-c is high), and pin 8 normally low through R25, pin 10 is at logic high and therefore pin 6 of ICll-b is also high. Since pin 5 of ICll-b is normally high through R45, pin 4 is then low, which represents the quiescent state of the cue timer. When the off-hook latch oper- ates, a logic high differentiated by 020 to a momentary high ap- pears at ICll-c pin 8. Since pin 9 is also high, pin 10 transitions low as does pin 6. With pin 6 low and pin 5 high, pin 4 now goes high. That high also appears at pin 8 through the charging ac- tion of C21 and, for the time being, the timer output (pin 4) remains latched high. As 021 charges through R25 and R26, the voltage on pin 8 de- creases. When the voltage dimin- ishes to approximately 1.5V, 1011- c sees a logic low and pin 10 tran- sitions high as does pin 6. With pins 5 and 6 both high, pin 4 goes low and the timing interval ends. The same timing action is triggered if a momentary logic low appears on pin 5 of ICll-b. This would occur upon operation of the screen-mode select logic as discussed earlier. Ringer The CallScreen ringer circuitry essentially takes a logic high on one of three inputs and produces one of three ring cadences which is delivered to the slave phone(s) as a 27-Hz, 90-volt RMS ringing voltage. The ringer also includes the 600-Hz cue oscillator which, along with cue timer functions, is keyed by the 27-Hz ring fre- quency oscillator to produce the "ring back" signal that the caller hears. The three ringer input lines are coupled through diodes D8, D9 and DIO to ring clock nand gate lC20-a pin 1 . When any one of the lines goes high, indicating the need to ring the slave phone(s), IC20-a is enabled and the ring clock begins to run. An as table multivibrator, made up from lC20-a and lC20-b, produces gat- ing pulses at pin 4 of IC20-b at 600 ms intervals when enabled by pin 1 of 1020-a being high. The repetition interval is determined continued on page 62 {limt=iataateBlstlimt=it=Bt=Bt=itsilfailfail(=psp=tlfaBt=BL=stet1i=s1fatfc=^ tCil Cut tbro^gb ^ Coofusioi) When you are repairing an y electronic equipment and need a reputable and dependable source for high quality, original Japanese Semiconductors see your authorized Thomson Consumer Electronics distributor CIRCLE -I9t ON FREE INFORMATION CARD FOR MORE INFORMATION AND A COPY OF THE LATEST PRODUCT/ PR]C£ LIST COMPLETE THE COUPON BELOW AND MAIL TO: JAPANESE SEMICONDUCTOR MERCHANDISING THOMSON CONSUMER ELECTRONICS 2000 CLEMENTS BRIDGE ROAD -^' DEPTFORD, NJ 08096-2088 HK=ll=Bl=tl=ll=tianli=ll=lt=llStlfaBlSit=ll=^l=Bt i s Please send me a copy of your Japanese Jedec Product/EVice List and a list of authorized distributors: Name Company Address City__ . State, Zip . Telephone IK9I% IC922 y z O a: H O LJJ _J UJ o < 58 THE CHANGING FACE OF SATELLITE TV Satellite television^ received on small, flat antenna panels f promises to give cable TV a run for the money. ROBERT ANGUS SATELLITE TELEVISION, DELIVERED to antennas as small as a table napkin, is about to become a re- ality. You might be saying to your- self, "So what's the big deal?" Futurists have been talking about that for as long as they've been talking about large-screen TV receivers thin enough to hang on the wall like pictures. And haven't Europeans and Japanese been watching TV using tiny flat- panel antennas for a year or more? Well, yes. But this time the talk is for real, with technology letting a single satellite deliver as many channels as a large cable system. Indeed, within three years, there could be at least six major pro- grammers broadcasting directly from satellite, offering up to 400 channels of pay-per-view (PPV) movies, premium sports events, concerts, and general entertain- ment programs. The first, TVN, was scheduled to start in September, with 10 channels of movies Etnd three of basic cable. TVN isn't truly a small-dish service, since it uses an existing low-powered satellite (Telstar 303) and a full-sized C- band satellite antenna, but it shows how such services will op- erate. Scheduled to be launched in October is K Prime, a 10-chan- nel service that also uses an ex- isting satelhte (Satcom Kl), but transmits to dishes 3-^ feet in diameter. The first satellite specifically designed for direct-broadcast by satellite (DBS) service will be SBS-6, scheduled for launch later this year It'll carry 10 chan- nels of PPV movies and special events beginning early next year. In late 1993, Sky Cable, the real biggie, should have 27 transpon- ders on three Hughes high- powered satellites capable of transmitting pictures to a flat, square antenna measuring a mere 14x 14-inches, called a "squarial." The same antennas will be able to pick up an addi- tional five channels from United States Satellite Broadcasting's bird located nearby. By 1993, however, all the pro- grammers listed above expect to offer many more than the 65 channels they plan to start with. Using digital signal compres- sion, they expect to multiply their capacity some 2—8 times, enabling Sky Cable to promise a total of 108 channels. TVN Presi- dent Stu Levin boasts that he'll have enough channels to be able to start feature movies every few minutes, so viewers can enjoy their choice of flicks virtually on demand. Large-dish satellite antennas are able to choose programming from 18 C-band and six Ku-band satellites, with well over 200 channels. In theory, they can also receive aU the new channels. Tb do so, however, the nation's two- plus million dish owners will need new decoders — separate ones for TVN, SkyPix, K Prime, and Sky Cable — since each firm plans to use different, incompati- ble, scrambling systems. The assumption of most DBS programmers is that viewers wiU select one of the competing sys- LI.IIL^IIIfll : DIGITAL VIDEO DATA terns, erect a small, fixed-posi- tion antenna to receive it, and rent or buy a dedicated inte- grate d-receiver-desc rambler (IRD). K Prime, for example, plans to charge $12 a month for a package with basic program- ming and reception equipment; PPV movies will cost $5 each. Sky Cable and SkyPix plan to sell hardware packages for $500—600, with viewers paying $5 each for new flicks. Uniden Corp. of Indianapolis, IN, has provided a glimpse of the potential satellite future. Their new Model 4800 receiver ($2499) uses not only the standard Vid- eoCipher II Plus decoding used by most C-band programmers, but also D-Code decoding for TVN. To keep track of the 120 movies TVN plans each day, as well as big-dish program listings, the Model 2400 has a built-in FIG. 1— THE Gl DIGICIPHER COMPRESSION METHOD. SOURCE material is digitized at the broadcast station or uplink site (step 1). An encoder extracts essential data from a frame. Ttie 1.2 gigabits per second of digital HDTV is compressed by motion-estimation and compensation methods (step 2). Only 2% of tfie bits are transmitted between frames; DigiCipher HDTV's receive the signal, and error-correction methods reconstruct the digital video (step 3). it's converted to analog, with no resolution loss (step 4). The Improvement is like comparing CD's to vinyl records. electronic program guide. Instead of selecting a sateOite and transponder, the viewer calls up the schedule for an appropri- ate viewing time, picks a pro- gram, hits "ENTER" on his remote control, and the receiver automatically sets the correct satellite and transponder. You can even program a whole night's viewing this way. Of all the technical miracles, the most important is digital sig- nal compression. It not only makes possible capturing several channels on a small fixed-posi- tion dish, but provides the band- width for everything from high- definition television (HDTV) to multichannel interactive video and specialized narrowcasting. It digitizes the information in a vid- eo frame, removes extraneous in- formation (so that what's left is compressed), and the data is transmitted. The only new data transmitted thereafter are frame- to-frame updates. Current video, by contrast, uses the National Television Standards Committee (NTSC) foi-mat, transmitting full, uncompressed video frames at 60 Hz. Suppose the program were the Talking Heads on the Tonight show: difference signals make up only about 2% of the total. How- ever, when there's lots of action and rapid movement in a pro- gram, the frame-to-frame § m CD m 33 (D ID O 59 changes can be up to 50% . Great- er compression without visible artifacts is possible when move- ment is minimized and the cam- era angle is constant. And when a video image has been com- pressed, the bandwidth needed to transmit it is correspondingly reduced. Compression basically makes video transmission into an adap- tive process, where the in- stantaneous bandwidth used at any given moment to transmit an image fluctuates as the amount of motion between frames changes. Such a procedure makes for the most efficient use of bandwidth, since it con- tinually varies and updates ac- cording to the video needs of the -^fnoment. In theory, it's possible to multiplex 10 such programs in the bandwidth used by a normal, single, broadcast, cable, or satel- lite channel. But if one program is a basketball game, its viewers may complain of streaks and fishtails as the ball and players move along the court. If you've ever watched rebroad- casts of older black-and-white (B/ W) programs from the 1950s or early 1960's (Uke the Honey- mooners), you can often see streaks and fishtails as the characters move or the camera pans, since the image orthicon tubes in TV cameras of the period lacked adequate resolution. Such streaks were quite conmion on bright metallic objects that tended to reflect excess light into the camera, saturating the tube phospor. Or, a nature program with closeups of flowers and in- sects may lack detail and appear washed out, making viewers complain. By reducing the total number of channels, broadcasters can improve the resolution of those that are left, since there's more available bandwidth. The ulti- mate extreme this way would be a true HDTV channel with digital surround sound, needing 1.5-5 uncompressed cable channels, but which can fit into a single cable or broadcast channel, using compression techniques. When compression becomes a re- ality— maybe by late 1991— aDBS firm might have one or two HDTV channels. They may use two or three more channels for sports or movies (where high resolution MAJOR HOME-SATELLITE BROADCASTERS Company Name Services Start date Satellite Longitudes Comments Comsat Video Multiple narrowcast channels Unavailable Unavailable Has compression system; developed 14 X 14-inch "squarial" antenna Directsat 2 medium- power satellites 1992 lOrW, 148°W None Dominion Video 8 transponders on 2 medium- power satellites Unavailable 119"W, US^W Educational and religious programming EchoStar 3 PPV movie channels, 3 Unavailable 61.5=W, 148"^ Basic-service channels in- premium movie channels, 10 basic-service channels, and 2 medium- power satellites clude religious, children's, and adult program- ming; will air 6-7 Pay-Per- View movies per month EMCa Movies on demand on C- band satellite using digital technology Late 1990 Unavailable Over 4000 feature films K Prime 10 channels on Sat-com K1 include 3 PPV channels Oct 1990 85°W Package available from cable operators through Netlink for about $12; includes 4-foot dish and proprietary IRD Plan compression to increase capacity 1992-1993 would be most appreciated), and have several 4:1 compressed channels for weather, business, children's programming, and family-type series reruns. The DigiCipher system There are almost as many ways to compress video signals as to scramble them, which may ex- plain why every DBS firm has its own compression and scram- bling methods. General Instru- ment GI Corp, plans to introduce the DigiCipher system next fall; it's likely to be first out of the box, and has already been used for Sky Cable's business plan. A spokesman for GI Corp.. Mike Walker, says that set-top black box decompressors on the market by then could run $200. When Sky Cable begins. Di- giCipher could be built into a TV for HDTV purposes. Fig. 1 shows the DigiCipher process, and Fig. 2 shows the major staff members at the GI Video Cipher Div, in front of a sample image. The Di- giCipher process Itself works as follows ; • The source material (like video movie or computer-generated art) is digitized at either the broad- cast station or the cable satellite programming uplink site (step 1 }. A DigiCipher encoder sorts non- essential data out of each video frame, • The 1.2 gigabits per second generated for digital HDTV is compressed by proprietary mo- 60 MAJOR HOME-SATELLITE BROADCASTERS Company Name Services Start date Satellite Longitudes Comments SkyPix 10 transponders on SBS-6 Jan-Feb 1991 Unavailable $500 package complete with 3-foot dish and proprietary IRD, PPV movies every few minutes, sports, and concerts Expandable to 80 channels with proprietary compression technique 1992-1993 Sky Cable 27 transponders on 3 Hughes high-power satellites Late 1993 101 'W $500-600 for system to include 14-35- inch dish, as well as PPV movies and sports; sold through cable services, in basic and premium versions Plans to expand to 108 channels using compression 1993-1994 TVN 10 PPV channels on Tel star 303, and 3 basic channels Sep 1990 125°W D-code descrambling, $25/month for basic service and IRD; available through Uniden dealers 2 added channels Jan 1991 Expects to add capacity using compression 1993-1994 USSB 5 high-powered Ku-band channels, expects to add capacity using compression Late 1993 lorw None FIG. 2— THE MAJOR STAFF MEMBERS AT THE Gl VIDEO CIPHER DIV. From left to right, Dr. Jerry Heller, Exec. Vice-President, Dr. Woo Paik, Asst. Vice-President, and Larry Dungham, President. tion-esttmation and compensa- tion methods (step 2). Thus, only 2% of the bits are transmitted be- tween successive frames (for minimal interframe motion) via broadcaster satellite to cable sys- tem head ends, and home satel- lite systems. • DigiCipher-equipped HDTV's receive and demodulate the sig- nal, and use potent error-correc- tion methods to reconstruct the transmitted digital video (step 3). • The reconstructed digital vid- eo is converted to analog for a crisp HDTV picture, with no sub- jective loss in resolution (step 4). The improvement in DigiCipher HDTV over NTSC format is like comparing audio digital compact discs (CD's) with vinyl records. Perhaps the most interesting apph cation of digital signal com- pression applied to DBS is by En- tertainment Made Convenient^ (EMC^), a Denver, CO, company that hopes to offer a library of 400 movies virtually on demand by late 1990. They propose to com- press movies in time and band- width, letting a full-length fea- ture film be downloaded to a VCR in about 12 minutes. The VCR would allow two view- ings per movie before erasing a tape automatically To receive the programs, transmitted via an as yet-unnamed C-band satellite, a viewer would need a small nap- kin-sized antenna and VCR with a dedicated, built-in satellite re- ceiver. The VCR would tape films digitally, so the tapes can't be played back on conventional VCRs. The catch is that digital VCR's don't yet exist, and major manufacturers aren't planning on them anytime soon. Since the same pool of feature films should be available to all the PPV hopefuls, and the majors promise to offer basic program- ming comparable to current basic cable and C-band DBS packages, there may not be much variety among various systems. All the PPV firms promise to have the top 10 box-office attractions when they appear in video stores. Hence the race by K Prime, TVN and others to be first, even if they have to recall receivers in a year or two when they start using newer, more powerful satellites. One feature TVN hopes to offer to distinguish itself from the competition is interactive video. s m □0 m J] CD O 81 SATELLITE TV continued Jrom page 61 to o z o CL h- O UJ -I Ui Q Q < IT SO the viewer can choose a cam- era angle on sports events, inter- act with contestants on a game show, or determine the plot of an action series. TVN has an ex- clusive agreement with ACTV, a Canadian company that's de- veloped a seamless way to switch between four video channels to provide interactive video. Until digital compression be- came a reality, interactive TV made no sense, since few cable operators and no terrestrial broadcasters had the needed channel capacity. TVN Vice-Presi- dent Stuart Jacob says his com- ~pany hopes to offer sports fans Interactive coverage of major sporting events like the Indi- anapolis 500, the 1992 Olympics and major-league hockey and baseball. Does all this mean the large dish is dead? No way. The pro- grammers who form the back- bone of cable TV and today's satellite viewing — HBO, Show- time, CNN, ESPN, MTV and the rest — are committed to largp- dtsh transmission through the year 2015. Over the next few months, they'll be joined by some 20 newcomers with everything from want ads and programs in Tkmil, to sci-fi and American Lawyer (a 24-hour channel for Perry Mason addicts). What sig- nal compression can do for small- dish DBS services, it can also do for large-dish owners. R-E CALL SCREENER continued Jrom page 56 by C27 and R35, and R34 pro- vides the feedback path to 1C20- a. Gating pulses from pin 4 of lC20-b begin clocking decade counter 1C23 whose ten outputs (they're not all shown) then begin sequencing, one at a time, to log- ic high. At a 600-ms clock rate, the counter will sequence through all ten outputs in 6 sec- onds, which is the standard ring cycle of the U.S. telephone sys- tems. Steering diodes D22-D29 are connected from the q outputs of the decade counter to assem- ble the three different ring ca- dences. Diodes D22, D23, and D24 are connected to the Ql, Q2, and Q3 outputs of IC23. As soon as the ring clock is enabled, Ql goes high for 600 ms, followed imme- diately in sequence by Q2 and Q3 for 600 ms each. The input of lC22-b (pin 5), therefore, sees a logic high for approximately 1.8 seconds IQH-Q2-I-93) out of every 6 seconds, thus producing a standard telephone-company like ring if IC22-b is enabled by pin 6 being high. In a similar manner, 1C22-C and lC22-a are supplied with logic levels corre- sponding to cadences as follows: 1C22-C— high 600 ms, low 600 ms, high 600 ms, low 4.25 sec- onds (two short rings and pause). lC22-a— high 600 ms. low 600 ms, high 600 ms. low 600 ms, high 600 ms. low 3.5 seconds (three short rings and pause). Each of the three ringer input lines is connected to one of the ring-cadence enable gates of IC22. Gate lC22-b is enabled via pin 6 from IC4-d pin 11 when the CallScreen is in the Limited Screen mode and the code-entry interval timer times out; this pro- duces a "standard" ring, signal- ing an unscreened call. Gate CALL ROUTING ADAPTER PARTS All resistors are %-watt, 5%, un- less otherwise noted. R101— 150 Ohms, Va-watt R102, R1 03— 10,000 ohms R104— 330 ohms R1 05— 1000 ohms Semiconductors D101-D106— 1N914 diode Q101,Q102—2N4401NPN transistor Other components RY101, RY102— SPOT miniature re- lay, 12-volt. 320-ohm (nominal) coil 8101, 8102— SPOT miniature switch (or use single DPDT center-off switch) J1, J2^modular phone jack 1C22-C is enabled via pin 9 from IC16 pin 7 when the correct pri- mary code is detected; this pro- duces a double ring and pause. Gate IC22-a is enabled via pin 2 from IC17 pin 7 when the correct secondary code is detected; this produces a triple ring and pause. The outputs of the ring-ca- dence enable gates are connected through diodes D30-D32 to the ring-frequency generator (pin 1 of IC24-a). Resistor R55 ensures a solid logic low in the absence of ring. Whenever pin 1 is high, the 27-Hz ring oscillator is running. Gates lC24-a and IC24-b are con- figured as an astable multi- vibrator producing approximate- ly symmetrical square waves of logic-low and -high levels. The frequency is determined by C46 and R66, and R65 is a feedback resistor. Steering-diode D38 is used to enable the 600-Hz cue os- cillator thus gating its output at 27 Hz, Resistor R67 ensures a solid logic low in the absence of enable signals. The ringback and cue os- cillator is an astable multi- vibrator consisting of IC20-C and lC20-d along with frequency-de- termining components C47 and R69, and feedback resistor R68. R70 and C53 form a low-pass fil- ter which sets the 600-Hz output level correctly for input to ICl-a. Enabling of the oscillator occurs on IC20-C pin 8 through either D38 for ringback or D39 for cue signaling tones. The output of the ring-fre- quency oscillator (IC24-b pin 4) is also coupled, through C26, to the input of op-amp IC25, which is configured as an active low- pass filter whose center frequen- cy is set to 20 Hz. That setting provides a frequency- propor- tional attenuation of the 27-Hz square wave supplied from the ring-frequency oscillator at an 18dB/octave rolloff rate. The out- put of 1C25 is very nearly a 27-Hz sine wave. Components R46 and C35 provide AC decouphng of V2 Vcc bias voltage to operate IC25 without a split power supply. Voltage divider R50 and potenti- ometer R51 set the input level to 1C26 for a 90-95 volts RMS ring- er output voltage. The LM383 7-watt power am- plifier (1C26) has its gain set by R72 and R73. Feedback for the inverting input is coupled through C41. while low-level ring voltage is connected to the non- inverting input via C40. Capaci- tors C42 and C43 stabihze IC26 against high-frequency oscilla- tion. C44 couples high-current ring signals to the 8-ohm pri- mary of T3. High ring voltages appear across the 8 kilohm sec- ondary of T3. The ringer config- uration is capable of reliably continued on page 77 62 R1 in R2 2Q ® 11 l^ TJ BYERS til Ica.EtElt r«1 131.[]Ef^[n m 3E3.[][]ni[n .EIC Breadboards are giving way to PC-based circuit simuiation. IF YOURE LIKE MOST ELECTRONICS hobbyists, you love to design and build circuits. Unfortunately, one of the hazards of the hobby is that many projects never get beyond the breadboarding stage because of design or debugging problems. Sure, you can spend countless hours troubleshooting a circuit using a plethora of test instru- ments, but wouldn't it be nice if you didn't have to touch a compo- nent until you were ready for the final assembly? Now you can, using the power of your PC and a growing number of circuit-sim- ulation programs. Circuit-simulation prograins are not new either to the comput- er or to the PC. What is new is that now these programs are af- fordable. Simulation prograins that sold for $20,000 ten years ago can be obtained today for less than $100. and thai low cost makes it cheaper and faster to simulate a circuit than to bread- board it. Another advantage of circuit- simulation programs is that they give us the ability to do'"what-if?" simulations. For example, what if you were to substitute a 0.01 |j,F capacitor for the 0.015 jjlF unit specified in a circuit design? Using circuit-simulation soft- ware, you could learn the answer in seconds. This is the first article in a two- part series that will look at cir- cuit-simulation programs for personal computers. This part discusses a venerable analog simulation program called SPICE, and the second part dis- cusses a powerful digital simula- tion program called SUSIE. Our bias is toward the IBM family, but versions of the programs we'll discuss are available for other platforms; we'll discuss prices and availability later. The SPICE of life SPICE (simulation program with integrated circuit empha- sis) is far and away the most pop- ular analog circuit-simulation program in use today SPICE was developed by the University of California at Berkeley in the late 60 's. and was released to the pub- lic in 1972. Over the years, SPICE has gone through many upgrades. The most important change came with SPICE 2, in which the kernel algorithms were upgraded to m CD m 3 1.4060+00 * + . 1.9960+00 * . + 2,4810+00 * . + , 2.182D+00 • . + 1,6410+00 * + . 1. 2600+00 * + . 1.0130+00 ) 8.4750-01 + * 7.2960-01 + • 6.4200-01 + * • 5.7430-01 + * 5.2060-01 + * 4. 7680- 01 + * 4.404D-01 t * 4,0970-01 + * 3.834D-01 + * 3. 6050-01 + * FIG. 4— SPICE GRAPHIC. This crude grapti uses ASCII characters, so It prints on any printer. with, and are beyond the exper- tise of most SPICE users. Fortunately, however, there's a huge inventory of ready-made SPICE models for many different types of components, including transistors, optoelectric devices, and analog and digital IC's. Most versions of SPICE come with a library of popular components, and you can usually obtain addi- tional libraries at extra cost. De- vice manufacturers are another source of SPICE models. For not- so-popular or oddball devices, you can buy specialty models from third- party vendors, or roll your own in a subcircuit. The maker of IsSPICE, Intusoft, pub- lishes a free newsletter that con- tains information and modeling tips for various types of elec- tronic devices. Plotting SPICE'S output Like most simulation pro- grams. SPICE generates a lot of data, and analyzing that data can z o < m m 3] O 67 m g z o \- O LU o Q be a chore. Like the netlist, all SPICE output files are in ASCII, which means you can transport them from one computer to an- other without conversion, or make a hardcopy of the file using just about any printer. Data is stored in the output file in the same order that SPICE performs its operations: the netlist, fol- lowed by the DC analysis, fol- lowed by the AC analysis. There are several ways to dis- play SPICE output in graphical form. The easiest is to add a .PLOT control statement to your netlist. SPICE then provides you with a tabular listing, similar to that generated by .PRINT, plus a crude graphical representation, as shown in Fig. 4. If you request more than one measurement within the same .PLOT state- ment on your netlist, you get a multi-line graph, which is handy for comparing two or more sets of measurements. However, .PLOT graphics leave a lot to be desired. Fortunately, however, SPICE's tabular format is accepted by most database, spreadsheet, and graphics pro- grams, including Lotus 1-2-3, The best way to prepare a SPICE output file for data import is to use a text editor to remove every- thing but the desired tables, and then import the data into the de- sired program. Figure 5 shows a 1-2-3 plot of the data in Fig. 4. Choosing a SPICE program When choosing a SPICE pro- gram, there are several factors to consider, not the least of which is cost. A SPICE package can cost anywhere from $100 to more than $20,000. The cheapest SPICE simula- tion package that we know of is IsSpice from Intusoft. which sells for $95. An accessory for IsSpice that lets you draw schematics and create netlists is shown in Fig. 6. By comparison, the popu- lar PSpice program from Micro- Sim goes for $950. The digital- simulation option for PSpice is shown in Fig. 7. The reason for the large difference in price be- tween the two is due mostly to the number of device models in- cluded. IsSpice comes with only a handful of transistor models, whereas PSpice comes with a transistor library containing more than 1500 devices, plus nu- R — SPICE OUTPUT Op A.mp Bondpass FUte FILE / \, / ! \ 5 - / \ / \ 1 / \, ,^ ^ L . \ T - P=i F=-« ^ ^ < \ >— 1 1 1 1 1 0^ 7 \, 1 — -1 2 - / ^ iv- \ - ,/ ^. / N ,/ N, fi - / N. 7 _ f ^•^ '^ -g - ^ --^ 1.0 1,1 1,2 1.3 \A 1.5 1.5 1.7 l.E 1.9 2.0 2.1 2.2 2.3 2A 2.5 2.6 2.7 2.8 2,9 J.O FrBwyou don't with our macro-scrotber kit. Ortginaffy Pubiishad in Radto-El^ctronfc^ . 70 Channel Cable TV Converter .$89.95 * 6 Function Infra-Red remote. * Fine Tuning. * Memory & Recall. * Compatible with all External Descrambler. * Channel 3 & 4 switchable output. * STD. HRC & IRC compatible. CALL TOLL FREE 1-800-332-3557 Outside USA Call 1- SOS- 699- 6935 Visa, MasterCard and COD. Add $4.00 5&H, $6.50 Outside USA. D & D Electronics, Inc. PO Box 3310, VISA MC N. Attleboro, Ma. 02761 CIRCLE 194 ON FREE INFORMATION CARD s m CD 77 to o z o □c H O UJ _i LU 9. § q: R Ji STANDARD RIKG OfTPS) o =ilMARy RING : (TPa o STANDARD RING (TPV) MODE SELECT disable; I /gkd CALLSCREEN =■ ; CALL ROUTIMG ADAPTtR R SECONDARY RING ADAPTER "OFF" FIG. 2— THE CALL ROUTING ADAPTER allows selective ring output to one of two output jacks. While the circuit is optional, there is space for the components on the main PC board. Standard telephones have their ringer devices coupled to the telephone line through very high DC resistances. In practice this coupling is usually capaci- tive. so that while on-hook, there is essentially no DC current path. When off-hook, a DC resistance of up to several hundred ohms is placed across the line. Any slave phone, when raised off-hook, causes DC to flow from the + 16V power supply, forward biasing the IC28's internal LED, through R74 and the secondary of T3, through the DC resistance of the off-hook phone, and back to power supply ground. The for- ward-biased opto-coupler diode turns on the phototranslstor whose collector is connected in parallel with the collector of the Darlington pair in 1C21 and through R58 to +5V. When 1C28 is turned on, the voltage at the lower end of R58 goes to nearly zero. That is coupled to pin 2 of comparator IC2 which causes 1C2 pin 6 to go high. The reference voltage for IC2 is developed by voltage-divider R60- R62; it is set to approximately 224 millivolts. When the voltage at pin 2 goes lower than 224 mil- livolts, the output of IC2 goes high. That output is coupled to pin 9 of IC9-C which, as part of the reset logic, sets a master re- set high and also causes RY2 to release. A master reset high will unlatch the off-hook latch. The result of these actions is that the slave phones now bypass the CailScreen and are connected di- rectly to the phone line, and the CailScreen is returned to on- hook. The output of IC2 is also connected to timer IC9-d which enables screen-mode changes for a period of approximately seven sec- onds after a slave phone is placed off-hook. That prevents screen- mode changes from inadvertenUy occurring during normal tele- phone calls in the event that the "*" and "#" keys are used. Buffer tC9-d drives timing components R57 and C58. When any slave phone transitions off- hook, 1C2 pin 6 goes high as does IC9-d pin 1 1 . That high appears through C58 on IC14-a pin 1, which enables remote screen- mode changes. As CSS charges, the voltage across R57 decreases. Wlien R57 reaches approximately 1.5 volls, pin 1 of IC14-a sees a logic low and remote screen mode changes are disabled. As soon as 1C2 pin 6 transi- tions high, C34 begins charging through D36 and R63; R63 lim- its the inrush current to C34 pre- venting a momentary voltage collapse at the cathode of D36. When RY2 drops, the slave phone connections are transferred from the CailScreen ringer trans- former to the telephone line. When the transfer occurs, 1C28 turns off and IC21 turns on. The LED inside IC21 is connected in series with the phone line through BR3 which ensures a correct polarity for forward bias regardless of actual phone line connections. Current for the LED comes from the telephone company central office. Since the collector of the Darlington pair in IC21 Is con- nected in parallel with 1C28, the bottom of R58 remains low and the master reset remains high. At this time, the slave phone has been connected and the Call- Screen is held reset and is effec- tively transparent on the line. If a slave phone is raised off- hook to make an outgoing call, the process is the same as de- scribed above except that when the slave phone is transferred to the telephone line, there is a mo- mentary interruption of the cen- tral office DC current from the time the central office detects a phone off-hook until a dial tone is returned superimposed on the restored DC current. During that interval, 1C2 pin 6 transitions low, but the now-charged C34 maintains a high on pin 9 of 1C9- c for approximately one second. That delay provides a ride- through capability that prevents RY2 from pulling in and even- tually rocking the off-hook slave phone back and forth to and from the telephone line. The discharge of C34 takes place through R63, R61, and the low output imped- ance of 1C2. Diode D36 is re- versed biased during this inter- val. The arrangement of R61, R63. and D36 is designed to al- low C34 to charge quickly, but. to discharge slowly. Resistor R59 limits current through IC21S LED while a for- ward-biased D35 eliminates any reverse voltages from appearing across the LED. When D35 is re- versed biased, the voltage across the combination of R59 and 78 Ji.| IC21's LED is limited to 5.1 volts, thus placing an absolute limit on the forward current through the LED. These precautions are nec- essary to protect IC21 in the pres- ence of telephone-company ring voltage when the screen mode is off, and also to protect against electrical transients that appear on the phone line. The detection of a slave phone off-hook while a ring voltage Is being developed across the sec- ondary of T3 requires that RC fil- tering be used to track the average DC voltage level on the collector of the phototransistor in IC28. Whiie the ring voltage is present, IC28's LED wil! be for- ward biased during a portion of each half cycle of ring current. Zener-diode D40 protects the LED in the same manner as D35 protects IC21. Capacitor C45 by- passes a major portion of the AC ring current around the off-hook detection circuitry, but some short-duration pulsing of the IC28 collector to ground does oc- cur. The combination of R56 and 033 act as a low-pass filter to re- duce the ringing pulses to an average DC level across the input of IC2. The DC level is above the comparator reference voltage so that ring pulses will not trip the slave-phone off-hook detector When the slave goes off-hook and the 1C28 collector transitions to solid low. the comparator output goes high. Call routing adapater The call routing adapter (CRA), shown in Fig. 2, allows selective ring output to one of two output jacks. A switch (SlOl)on the CRA allows user selection of either an- swering machine or computer/ facsimile machine operation. When SlOl is in the "ans mach" position, all un-screened calls ring through JI. while all screened calls ring through J2. When SlOl is in the "comp/fax" position, all secondary-code calls ring through J2, while all un- screened and primary-code calls ring through Jl. Another switch (S102) allows the user to de-acti- vate the feature permitting all CallScreen processed calls to be available on both CRA output jacks. The CRA derives all control signals and power from the base CallScreen unit. With the CallScreen in a stand- by condition, both RYlOl and RY102 are de-energized and both output jacks (Jl and J2) are con- nected in parallel through to the CallScreen output poles on RY2. This permits normal processing of outgoing calls generated by an off- hook condition on Jl or J2. When an incoming call is deter- mined to be un-screened, TP2 (in the main circuit) goes high si- multaneously with the activation of the CallScreen ringer. When TP2 goes high. Q102 is turned on through D103 and R103. closing the contacts of RY102. The con- tacts on RY102 transfer the out- put on J2 from the CallScreen ringer directly to the CallScreen off-hook detector. That prevents CallScreen ring voltages from reaching any telephone(s) con- nected to J2. RYlOl, however, re- mains de-energized and the standard ring (for an un- screened call) is delivered to Jl. Assuming that SlOl is in the "ANS MACH" position, it is appar- ent that a logic high on either TP3 or TP4 will similarly energize RYlOl preventing screened-call ring signals from reaching Jl. while J2 receives screened-call rings. In this mode, the answer- ing machine is connected to Jl and the telephones to J2. When SlOl is in the "COMP/ FAX" position, the same ring lockout technique described above is used so that primary and un-screened call rings are pre- vented from reaching J2 and sec- ondary rings do not reach Jl. In that mode, the computer or fac- simile machine is connected to J2 and the telephones to Jl. Resistor RlOl reduces the 16- volt supply from the CallScreen to a nominal 12 volts for opera- tion of the CRA relays. R102 and R103 are current limiting re- sistors while R104 protects the CallScreen off-hook detect circuit from excess current, should a short to ground occur across Jl- J2. Diodes D101-D103 are steer- ing diodes, while D104 and D105 act as back-EMF surge sup- pressors. When 8102 is closed, a logic low is placed through D106 and R105 across the screen-mode select line which disables remote screen changes. That's all we have room for this month. Next time we'll go over the assembly and provide parts- placement diagrams. R-E Put Professtonol Knowledge and a COLLEGE DEGREE in your Technical Career through HOME STUDY Add prestige and earning power to your technical career by earning your Associate or Bachelor degree through directed home study. Grantham College of Engineering awards accredited degrees in electronics and computers. An important part of being pre- pared to move up is holding the right college degree, and the abso- lutely necessary part is knowing your field. Grantham can help you both ways — to learn more and to earn your degree in the process. Grantham offers two degree pro- grams — one with major emphasis in electronics, the other with major emphasis in computers. Associate and bachelor degrees are awarded in each program, and both pro- grams are available completely by correspondence. No commuting to class. Study at your own pace, while continuing on your present job. Learn from easy~to-understand lessons, with help from your Grantham instruc- tors when you need it. Write for our free catalog (see address below), or phone us at toll-free 1-800-955-2527 (for catalog requests only) and ask for our "degree catalog." • Accredited by the Accrediting Commission of the National Home Study Council GRANTHAM | College of Engineering S 250 Frontage Road g Slidell, LA 70460 ° 79 Welcome to. . . 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No Foreign orders. Name Address City^ All Orders payable in U.S^ Funds only. . State . .ZIP ON SALE AT QUALITY NEWSSTANDS, CONVENIENCE STORES AND SUPERMARKETS STARTING SEPTEMBER 13, 1990 — $3.50-U.S.A. — $3.95-Canada IC SPOTLIGHT Once simple page buffers, today's graphics coprocessors provide powerful display muscle for sophisticated, high-end graphics systems. i MIKE MULLIN rimBsetwd- With graphics subsystem technology progressing at such a fast rate, it can be difficult to keep track of all the latest trends. We'd like to illustrate those trends by giving you some insight into the internal operations of some of the newer power-packed graphics coprocessors. Graphics subsystems of the past were simply dedicated multi -ported memories with high-speed digital-to- analog CD/A) converters. Those coprocessors provided CRT control, screen storage, display, and refresh operations v^ithout loading down a host processor However, the host processor still had to perform all the complex graphics operations in the computer, including raster and vector manipulation, pixel-color and inten- sity-control, pan and zoom functions, and so on. Graphics subsystems of today can execute higher level transformation and rendering tasks than those of the past. These more advanced pro- cessors can perform rotation, moving and zooming, as well as vector-to- raster conversion and color and di- thering calculation to express image depth. Even though a graphics processor doesn't have to handle all of the usual central processing unit CCPU) func- tions, it does require a great deal of throughput for the tasks it performs. Simply refreshing a megapixel C1K X 1K pixels or more) screen with 24-bits of data per pixel (for color, intensity and depth) requires a throughput of 90 megabytes per sec- ond in non-intedaced (30 screens per second) mode. Texas Instruments CTI) has entered the market with their widely used TMS340XX and TMS320XX series of "Application-Specific" dedicated graphics processors. Cut from the same basic core, those processor families provide a wide range of graphics and digital signal processing CDSP) functions for a diverse range of system complexities — the 34010 and 34020 are aimed at the PC and low-end workstation markets, while the 320XX series is aimed at DSP. super-high-resolution C4Kx4K pix- els) and 3-D graphics markets. The 34010's internal structure uses a 32-bit general-purpose integ- er processor with clock speeds up to 50 MHz. On-chip, host-interface logic allows the target system's host CPU to access the 34010 and to map it's memory into that of the host pro- cessor, thus providing a fast way to swap data commands and status in- formation between the 3401 and the host. There is a 256-byte instruction buffer on chip, as well as two register files that contain 15 32-bit registers each. The 340XX and 320XX series use an on-board arithmetic logic unit (ALU), which enhances their com- putation. Most register-to-register operations are done in a single clock cycle, and two operands can be load- ed into the ALU in a single cycle. In that same cycle, the ALU can pro- cess the last-loaded pair of operands and transfer those results back to the register files. The result of that ar- rangement is that ALU operations seem to occur on one cycle. Bringing further flexibility to that scheme is a 32-bit barrel shifter that shifts or ro- tates 32 bits of data any number of positions Cup to 32) in a single ma- chine cycle. To further customize the 34010 to graphics applications, a part of its in- struction set is dedicated solely to graphics functions. Among those 23 instructions are commands for draw- ing and filling lines, arcs and polygons and for manipulating single pixels and blocks of pixels. Last year, Tl introduced the 34020, which has similar architecture to the 34010. but several improvements. For example, its data path is 32 bits wide, twice the width of the 34010. The on-chip buffer is 512 bytes, also twice the size. In addition to a host-processor in- terface, the 34020 adds interfaces for a floating-point coprocessor (the 34082) and for multiprocessor opera- tion. The 34010, which Tl will still pro- duce, but will target towards low- cost, high-volume applications, can be used with a math coprocessor. Instead of a direct connection, mem- ory mapping techniques are used. Now that you've gotten an idea of what the Tl 340XX and 320XX graph- ics processors can do, let's look at how another manufacturer's device handles graphics applications. Intel's "superchip" Like their general-purpose coun- terparts, graphics processors are evolving to RISC Creduced instmc- tion-set computer) architectures and parallel processing. A good example of this trend is the Intel's i860. Re- leased by Intel as a supercomputer on a chip for general-purpose com- puting, it quickly became the coprocessor of choice for high-end graphics systems designers. The i860 has a 64-bit RISC integer processor at its core, and allows pro- grammer control over pipelining, buff- ering and parallel processing, includ- ing synchronization and interlock operations, for optimum instruction sequencing. In addition to that feature, the i860 uses a floating-point processor with parallel adders and multipliers, for more efficient execution of common tasks such as fast Fourier transforms CFFT's), graphics transforms and lin- ear equation solutions. Three on-chip buffers — instruc- tion, data and translation lookaside — allow single-cycle access of data and code at high clock speeds. The in- struction buffer holds 4 kilobytes and can transfer 64 bits at a time. Since o instructions are 32 bits wide, two in- m structions can be transferred along ^ the bus with each cycle. The 8 kilo- 3 byte data buffer passes data to the ^ CPU 128 bits at a time, so 16 bytes 8 ai CO o z o o < IT ^^^^^^H ^H pimFTERNAL BUJ^HI ^^^^^^^^^V ■■ ■ ^IH iV n ■ ll - — H HOST ^^^ PROCESSOR ^^-J .^^.'iLI™ !^^^ GRAPHICS ^^^^B COPROCESSOR 2 COPROCESSOR ^^^^^K FUHCTIONS) ^^^ (SHADING. ETC.) ^^^^^ ^™ ^^1 ^ INSTRUCTION PlPELmEl — ^^— ^ ^| ^^^^^^^^^ ^^ 1 ^1 ■. .K. ^^^^^F 1 k ^^^^K RED GREEN BLUE ^^^^^^^^^^^^B inni/im '^^^^^H TABLE 1 VIDEO DAC's 1 ^^^^^^^^^^^^^^^^L Bp^^H^^v!^' ■■■■■■1 ■ RG. 1— FOR VERY SOPHISTICATED SYSTEMS WITH high throughput and 3-D shading, a second coprocessor is often used, as shown here. Intel's i860 performs vectorizable tasks such as panning, zooming and rotating. The Texas Instrument's 320C30 does floating-point tasks such as clipping and shading. can be transferred in one clock cycle. As you can see, the i860 is not only efficient, but quick as well. With the data buffer, vector data can be read from the external memo- ry at the same time as vector results are read into the data buffer. The translation lookaside buffer stores mapping information on the 64 most recently used pages for use by the memory management unit, which saves overhead in page lookup and translation. When it comes to graphics-specif- ic hardware, the i860 shows its mus- cle with a 3-D graphics unit that provides pixel interpolation and Z- buffer checking as well as color-inten- sity shading and hidden surface elim- ination through the use of Z-buffer algorithms. Color lookup tables A basic problem in megapixel dis- plays is the amount of memory used to describe the screen — especially since high-performance graphics dis- plays need to provide a very large and accurate range of colors for a realistic display. Those displays usually need one byte of data to control the inten- sity of each of the three guns in a color CRT. Because of that require- ment, a IKxIK pixel screen uses three bytes for each pixel, so three megabytes of data need to be stored for each screen image that is manipu- lated or stored. That takes its toll not only in memory cost, but in throughput demand on the graphics processor Color lookup tables CCLUT's), such as those from Inmos, are inter- faces between the output of graphics controllers and the analog input to the high-speed displays which they control. A typical 8-bit CLUT chip lets the user select 256 colors from a possible 16 million (24 bits) and map an address in that 1 6 million for each. The user can select just the 256 col- ors from a 16-million item palette, without addressing all 16 million. Those colors don't have to be evenly spread or related to each other so the user has a good selection of flesh tones for example, and uses only three or four blues or greens for their application. Tying it together Now that we've seen how the IC's work, lets take a look at how they can be connected to one another in a typical system. Even though we're examining a high-end system, you should be aware that only specific portions of that system would be nec- essary for less complicated specifi- cation requirements. If resolution is you're only concern, then an off-the-shelf graphics coprocessor, such as the 34010, can provide all the features you need. However a high-resolution, full-color system using the 34010 needs 24-bit color data. Three million bits of data, therefore, have to be transferred for a megapixel display (1024x1024 or 1152x900). To reduce the size of the color-defi- ning word, a color look-up table is added at the output of the system. The CLUT translates the output byte to one of 256 24-bit addresses, defi- ning a color as if it was called with a 24- bit word from the coprocessor For very sophisticated systems that require the highest throughput, where 3-D shading is involved, a sec- ond coprocessor is sometimes used in a graphics-pipeline configuration, as shown in Fig. 1 . The latest group of graphics workstations made by Hewlett Packard and Apollo uses In- tel's i860 IC for vectorizable trans- form tasks such as panning, zooming and rotating. The Tl's 320C30, with an advanced 34020 core, handles floating-point tasks such as clipping and shading. For that type of high-end system, data first passes to the i860 from the host CPU over the host bus, and then passes to the next processor at much higher speeds over an internal bus designed specifically for the graphics subsystem. The results of the last processor on the pipe pass to the lookup table and then through the DAC's to the display. The configuration we have just de- scribed represents the highest reso- lution system possible. Simple CGA, EGA or VGA boards that drive TTL monitors, such as those on a stan- dard PC, can be built from parts kits made by several vendors, including Chips and Technologies. There's not too much challenge in building from those kits, and they do provide sav- ings and flexibility. However if you vrant to push the limit of graphics ca- pabilities, the IC's we've discussed here will let you do it. In fact, they can be used to developed systems that are so fast that you might be hard pressed to find a monitor that can keep up with them! R-E 82 l=M''^it-^H=MJ=< After some final words on video, we'll continue with our controller. ROBERT GROSSBLATT A few months ago I did a series on video that ran over several issues of the magazine (Ra- dio-Eiectronics. January 1990- August 1990). As with most of the stuff done in this column, the general idea I had was to go through the basics of video theory and produc- tion. Since it would be wrong to as- sume that any of you have a real familiarity with any of the subjects discussed here, I have to be sure and lay a good theoretical foundation be- fore I start developing hardware de- signed to demonstrate the theory we're talking about. Every time we start a new subject, there's a conflict between the scope of the subject and the amount of space I have to cover it. The column space is limited and, to be fair to everybody, I can spend only a certain number of columns on any one par- ticular subject. Remember that not everybody is interested in everything. When I started the series on video, I fully intended to take it o bit further and describe the theory and design of circuitry that would put images up on the screen. It seemed to me to be a good way to end the subject. But, as with a lot of things in life, it just didn't turn out that way. In the first place, it took longerthan I thought to go through the theory of the video standard, and designing cir- cuitry to generate the video wave- form was complex enough to fill several consecutive issues of the magazine. It doesn't do anyone any good to dump schematics on the page unless they're well docu- mented. Since the purpose behind all the stuff I do is to have people learn, complete descriptions of the hard- ware we develop here is every bit as important as the hardware itself. By the tinne I finished the basic vid- eo hardware I had already spent sev- eral months on the subject and I realized there would be no room to go into producing images as well. But there's more to it than that. If you followed the video series you should realize that the circuitry needed to generate things like bars and dots realty has nothing to do with video. As ! mentioned in the series, all you need to put these type of images up on the screen is a regularly prciduced stream of highs and lows whose timing is locked to the sync signals generated by the circuitry we designed. This certainly isn't a trivial thing to do and, while there's all sorts of stuff you can learn by designing something like that, it's also a fact that it's not video circuitry either Even though it would have been great to do it here, it would have taken too much room to do properiy. And since we had gone over all the necessary theory, I decid- ed to use the subject as the basis of a contest. If you've seriously followed the video series, understood the the- ory and built the hardware, there's no reason why you can't work out the image-producing circuitry yourself. It's a good exercise in design, and figuring out how to lock it to sync is the best way I know of to see if you really understand the video circuitry we developed together I've already gotten some contest entries in the mail, and I'm amazed at some of the schemes used to put TFSoSa I..- - -^TER- 1 ■f V rcA/ff o^/r 3 2 1 J TC^£ £NA&1^£, /vyc £13 /3 S///&LE roMe 4 G^O&P SBL.EC.T /:>Z 1/ S SA/£y ^/ /o \& OSC/A/ ^£} I] 7 a^c ci/T MUTE a FIG. 1— THE 5088 DTMF GENERATOR is designed to be used under micro- processor control and, instead of tlie eight lines normally needed for keypad control, the digit Is sent as four-bit binary information to the four data inputs. images on the screen. My hat's off to everyone. Before we get back to the hard- ware stuff we were talking about last month, there's one more thing I want to get off my chest. A lot of people have written in asking me to show them how to beat scrambling and to put the circuit details in the column. I went through the basics of video scrambling at the end of the series and, if you read it, you know that there are lots of scrambling schemes in use across the country. There's no way for me to do it — ^it's just not going to happen here. You can't design circuit- ry to beat scrambled video without understanding how unscrambled vid- eo works. Once you've got a good handle on video, you should be able to throw the scrambled signal on a scope, figure out what's being done to mess it up, and work out what you have to do to straighten it out. I've said this lots of times before but Grossblatt's twelfth law is worth repeating: You have to know the rules to be able to break the rules. So, the only way you're going to be able to correct a scrambled signal is to know what's being done to scramble it in the first place. Enough. Latches and more latches The last time we left our controller design, we were talking about latches. So, before we go any further, you should have enough latches on your breadboard to cover all the port lines you plan on using. When I de- sign circuitry, I have a real aversion to unused silicon. I can't tell you why, but it really bugs me to have unused gates and IC halves sitting on the board that do nothing other than draw current. It may have something to do with my toilet training, but I'll spend a lot of time making sure that every- Q thing on the board has a purpose. g It's impossible to know how many oj latches to add to the board unless 33 you know what you're designing, so ^ the time has come to decide what we o R-E Engineering Admart "n FCC LICENSE PREPARATION The FCC has revised and updated the commercial license exam. Tiie NEW EXAM covers updated marine and aviation rules and regulations, transistor and digital circuitry. THE GENERAL FIADIOTELEPHONE OPERATOR LICENSE - STUDY GUIDE contains vital information. VIDEO SEMINAR KITS ARE NOW AVAILABLE. 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JlSft ^.j f n.iit'^'^'t0 ■ft/orwtt ortyyvT] t33S ■■., > a^j.fr'^oa w/{j''¥»f.ass*mtilBr,simuljwr/d»buS5ftr, . ms MCfiM-3 PrDflTamnttr TOr MflEOirOll HCGBHCrOSCe, H«C4 Parts haiiet]iJ'Qgeri Rt. W3, BoK flC TEL: {602) 525-3459 BortorK. VT, LfSA USSSJ FAX: (SQl) S25-34S1 MIDI PROJECTS •jSSftj BP18Z — MIDI interfacing enables any so eqiipped instruments, regardless of the manufacturer, to be easily connected to- gether and used as a system with easy com- puter control of these music systems. Comhinea computer and some MIDI instru- ments and you can have what is virtually a programmable orchestra. To get your copy send $G.95 plus SI. 25 for shipping in the U.S. to Electronic Technology Today Inc., P.O. Box 240, Massapequa Park, NY 117B2-0240. CIRCLE 182 ON FREE INFORMATION CARD CIRCLE 215 ON FREE INFORMATION CARD want the circuit to do. Now every- body has their own ideas but since I have no way of finding out what's in your mind Ccolumns are written sev- eral months before publication), it seems that a neat thing to design would be a telephone dialer Everybody uses a telephone and having a circuit that hangs off a paral- lel port and talks to the phone line can open a wide range of design pos- sibilities. Lots of bells and whistles can be added to it and, If the software is well written, the circuit can be the basis of a really useful product. The heart of any telephone dialer is the generation of DTMF tones and that's something we've done several times in the past. It's worlh your time to hunt through the back issues of RE and find the ones in which we de- signed our remote control system since those issues contain a good description of the entire DTMF stan- dard (Radio-Electronics, January, March, and April 19871 If you don't keep any back issues around (al- though you really should), you might be able to find copies of those months in your local library. Generating DTMF tones used to 2 be a real pain in the neck but things g got better several years ago when § semiconductor manufacturers saw t the problem as a hole in the market, y As things stand today, there are a fi, slew of DTMF generator chips 5 around and once you've worked out cc exactly what your needs are, you can be sure there's a chip available with ail the ins and outs you're looking for. Since we're going to drive the chip off the parallel port, one of the over- riding considerations for us to keep in mind is that we should conserve lines. Most of the DTMF chips want to see the row and column inputs produced by keypads. This means that eight lines have to be devoted to selecting the tone you want to gener- ate. We have eight data lines at the output of the parallel port but it's a good idea to be stingy with them since using them all to control tone generation will limit what we can do later on. Fortunately for all of us. National Semiconductor (and possibly other manufacturers), makes the 5088 DTMF generator. This chip has been designed specifically to be used un- der microprocessor control and is driven with straight binary. Instead of the eight lines needed for keypad control, the digit is sent as four-bit binary information to the four data inputs of the 5088. The pinouts of the 5088 are shown in Fig. 1 and. if you're at all familiar with DTMF generators, you should be able to recognize the rest of the controls on the chip. If you have a hard time finding this chip, or if you decide — for whatever reason — to use a different one, you'll have to modify the circuitry we'll be developing. This is especially true If your chip has to be driven with eight data lines. As an alternative, it doesn't take a lot of circuitry to con- vert the four lines I'll be using to the eight lines needed by other DTMF generators. Probably the easiest way to do something like that is to pro- gram an EPROM to do the con- version for you. It wastes a lot of EPROM space but it's quick. Aside from the weighted binary in- puts, the 5088 has a tone Er^jABLE input that, besides inhibiting the genera- tion of tones, also puts the chip into a low-power state that drops the cur- rent requirements to only 55 micro- amps. That isn't nsally such a big deal since even while the chip is active it draws only 1.5 milliamps. Pins 3 and 4 allow you to sepa- rately generate the high and low group tones that make up the DTMF standard. That's handy when you're setting things up since you can check the frequencies. The mute pin is an output that becomes active when the chip is generating tones. It's gener- ally used to turn off the telephone handset to prevent the tones from being heard while they're being gen- erated. The main use for that is in the design of telephones, but most of the phone designs I've seen don't bother doing that. Using the chip is easy since it only takes the addition of a cheap color- burst crystal to make things work. When we get together next month, we'll put it in the circuit, write some minimal software, and add some bells and whistles to the design. R-E 84 iTTTTTT7iiij.Fi%j Audio Test Reports: What they do and don't tell you LARRY KLE N In a recent column on the Audio Engineering Society's "Sound of Audio" conference, I mentioned that the session on hi-fi product test- ing drew a surprisingly wide range of interested^and interesting — ques- tions from the audience. As the per son who for two decades was in charge of the testing program at Stereo Review, I was asked to pro- vide some personal insights into the special problems of audio-product evaluations. Although I didn't do the • actual lab testing, I selected and scheduled the products for evalua- tion. And, more important, I dealt with the problems, both technical and po- litical, that inevitably arose. Test-report results Obviously, any successful maga- zine — audio or otherwise — ^must serve the interests of both its readers and its advertisers. If a nnagazine fails its readers, it loses circulation: if it fails its advertisers, it loses money. (Most magazines more or less break even on circulation; their income is almost totally dependent on advertis- ing revenues. The higher — and more specialized — the circulation, the more the advertisers are willing to pay to be part of the action.) In other words, a magazine with a substantial readership interested in quality audio components provides the best sort of marketplace "bulletin board" for those seeking to sell such products. So far so good. But if prod- uct evaluations are popular among the readers Cand th^ are), how does a test report tell the readers that something is wrong with a specific product without upsetting its man- ufacturer? In fact, isn't there a contra- diction between keeping the man- ufacturers happ/ — and continuing to advertise — and sen/ing the reader by exposing a product's faults? Editors deal with such problems in the same way that porcupines are said to make love — very carefully! ^ Test-report policies Magazines differ in the way they handle product test reports. Some publications automatically send out LISTENING TESTS should be validated by laboratory tests, and vice versa. the edited, but not published, report to the manufacturer of the product. The manufacturer is allowed to point out factual errors, but is not permit- ted to change the evaluation. If the manufacturer really has problems with the test report, he might be given the option of requesting that it not be published. Other magazines keep their reports close to the vest until it appears in print. When it appears, the manufacturer might throw a party and order several thousand reprints, shake his head and say it could have been worse, or cancel his advertising and call his lawyer Having worked for three different magazines over a 25- year period, I've encountered all three reactions. Some audio manufacturers tend to blow a gasket if any fault, however minor is found with their equipment. Others express hurt feelings by phone or letter, and a few are happ/ as long as you get their brand name and model numbers right. Although editors have a lot of day-to-day auton- omy, the ultimate policy maker is the publisher who is responsible for the magazine's overall editorial policy and income — two not-unrelated areas. One of my "unfavorite" stories il- lustrating the sensitivity of a man- ufacturer goes back to the time when I was giving a talk before an au- diophile society. One of the members asked me about a speaker system designed to achieve a special spatial effect by bouncing most of its sound off a rear wall, I said that like other speakers that radiate a significant portion of their sound away from the listener, it was somewhat sensitive to room positioning. Apparently some- one ftDm the audience subsequently asked the manufacturer about my comment, because within a week he had canceled his advertising contract with my magazine. He ultimately re- turned to the fold, but not before our publisher had lost perhaps $50,000 in advertising revenues. That sort of manufacturer behavior tends to keep editors from expressing themselves freely, but fortunately, during my 30 years or so as an editor only three of four cases of such blatant attempts at intimidation occurred. My personal policy was to check with the manufacturer on anything that seemed askew with the product. Because of scheduling exigencies, most components tested were early or pre-production models and some- times would not be as bug-free as the units that would ultimately reach the consumer As a result of our tests, we were frequently able to alert the man- ufacturer to needed design changes — and everyone benefited as a result. The product would be retested after it was reworked. Occasionally there would be a question of the significance of some high touted special circuit in the eval- uated product. If the product worked well, but the special virtues of its, say. "double-alpha lateral feedback" cir- cuit or the use of Litz wire in its inter- nal wiring were not apparent, we said so. continued on page 92 9 m m 3J ID o »s COMPUTER CONNECTIONS SCSI/ESDI Shootout and a pair from Micropolis JEFF HOLTZMAN Disk performance remains one of the chief bottlenecks in PC performance today. The ven- erable ST-506 interface, Introduced in 1980, provided adequate perfor- mance for eariy DOS machines, but today's generation of fast 386 and 486 CPUs far outstrips the ST-506's ability to keep up. For that reason, two more recent disk-interface stan- dards have been gaining increasing acceptance aver the past few years: SCSI (small computer system inter- face) and ESDI (enhanced small de- vice interface). The two are similar in that they allow increased perfor- mance, but there the similarity ends. Currently, ESDI holds the heav- yweight title for high-performance PC systems, but SCSI is coming on strong. This month I'll give an over- view of the differences between the two technologies, along with my ex- periences using drives of both types. Different strokes Probably the single most important difference between SCSI and ESDI is that SCSI is a high-level, intelligent interface, whereas ESDI is a low-le*/el interface that in some ways resem- bles a plain old ST-506, albeit a sig- nificantly faster one. The tesic data-transfer rate (DTR) of an MEM hard disk connected via a standard ST-506 interface is about 5 MHz; with an RLL drive. DTR in- creases 50%, to 7.5 MHz. By con- trast, the typical ESDI system has a DTR of 10 MHz. but the ESDI spec supports a ma»mum DTR of 24 MHz. and systems that approach that speed are becoming available. ST-506 and ESDI interlaces deliver data in serial fashion. By contrast, an g SCSI system delivers data in parallel z form across an eight-bit bus. The the- § oretical maximum transfer rate of that Q bus is 4 megabytes/second, but y eight bits are transferred at once, so ^ the overall rate is 32 MHz; quite a bit 5 higher than ESDI's maximum. Of S course, the actual throughput achievable in the real worid depends on a number of factors, including the hard disk drive, the controller, the computer bus, softvrare drivers, and host operating system. An ST-506 drive is relatively stupid; at the other extreme, a SCSI drive must have a microprocessor to inter- pret and execute commands. An ESDI drive fits somewhere in the mid- dle. The extra intelligence required by ESDI and SCSI drives is part of the reason for their high cost, relative to ST-506 drives. Lack of volume is probably the main reason for the cost differential: but as the market moves toward graphical operating environ- ments, high-performance disk drives will become increasingly popular, so prices will fall. An ESDI controller connects to a hard disk (or other device) by means of cables that are physically identical to ST-506 cables, including a 34-con- ductor contrx)! cable and a 20-con- ductor data cable. Many of the signals carried on an ESDI cable have names and functions that are similar to the corresponding ST-506 inter- face. However, there are definite dif- ferences, so you cannot connect an ST-506 drive to an ESDI contraller, or vice versa. The functions of the sig- nals on those cables include drive- select, head-select, status, clock and data lines, etc. By contrast, a SCSI interface con- ITEMS DISCUSSED • 1674-7 SCSI PC-Pal< ($1895), 1654-7 ESDI PC-Pak ($1895), Micro- polls Corporation, 21211 Nordhoff Street, Chatsworth, CA 91311. (818) 709-33(X3. CIRCLE 41 ON FREE INFORMATION CARD • Alfred Gli^sbrenner's Hard Disk Handbook ($39.95), Alfred Glos- sbrenner and Nick Anis, Osborne McGraw-Hill. 2600 Tenth Street. Beriteley.CA 94710. CtRCLE 42 ON FREE INFORMATION CARD sists of a fifty-conductor cable that looks more like the expansion bus of a computer than a set of control sig- nals. In fact, the SCSI interface really is a bus with eight data lines, a parity bit, and nine control signals that ariai- trate which device gets to talk at any given time. A new SCSI bus stan- dard, SCSl-ll, is due to be complete soon; it will allow 16- and 32 -bit trans- fers and will also provide better defini- tion of software standards. Both SCSI and ESDI intedaces al- low a theoretical maximum of eight devices. However, most ESDI con- trollers for PC's allow only two de- vices. By contrast. SCSI really has almost unlimited expansion potential, because as many as seven of the eight devices may have as many as eight logical units, each of which may have 256 logical subunits, allowing a maximum total of 14,336 devices connected to one bus. SCSI clearfy has a great advantage over ESDI in this respect. The ESDI interface has several sig- nals for selecting a particular device and exchanging data with it. By con- trast, SCSI has a data bus and sig- nals for controlling the flow of information on that bus. However, SCSI has little to say about the contents of that information, and that leads to a good-news/bad-news sit- uation. The good news is that because the SCSI interface doesn't know any- thing about the underlying hardware, it is theoretically possible to connect several different types of devices to a single SCSI bus simultaneously. In fact, the SCSI interface was con- ceived from the beginning as provid- ing a flexible means of connecting devices of all types, including hard disks, tape backup units, CD-ROM drives, writable optica! drives, laser printers, scanners, and even network interface adapters. With some com- puter systems (notably the Macin- tosh), that is indeed the case. The bad news is that, in the PC 86 Rates: Ads are2V4" y VAT. One insertion $950. Sir Insertions $925.each Twelve insertions S895. each Closing date same as regular rate card. Send order witti remittance lo Computer Admsrt, Radio Electronics Magazine, 500-8 Bt-County Blvd., Farmingdale, NY 1t735 Direcl teleptiDne inquines to Arline Fishman, area code-5t&-2S3-SnO. Oatf 100% Computer ads are aceeftted far this Mmmt. ' GETTING THE MOST FROM YOUR PRINTER BP1S1— 4t Is probable that 80% of dat^ma- trix printer users only ever use 20% of the features offered by their printers. TTiis book will help you unlock the special features and capabilities that you probably don't even know eidst. To order your copy send $6.95 plus $1.50 far shipping in the US. to El ec- tranic Tectinology Today Inc., P.O. Box 240, Massapequa Parit. NY 117620240. SECRETS OF THE COMMODORE 64 BP135 — A beginners guide to the Commodore 64 pre- sents masses of useful data and programming tips, as well as describing how to get the best from the powerful sound and graph- ics facilities. We look at how ttie memory Is organized, random numbers and ways of generating them, graptiics-co(or-and sim- ple animation, and even a chapter on ma- diine code. Get your copy today. Send ^.00 plus $1 .25 for shipping in the U .S. to Electronic Techalogy Today Inc., P.O. Box 240, Massapequa Park, NY 11762-0240. CIRCLE 61 OH FREE worid, that type of bus sharing is diffi- cult to achieve at the present time. "Rie reason is that, although the elec- trical standards for the SCSI bus are well defined, the software commands that tell the hardware what to do are not. In fact, the original SCSI stan- dard specified only a single com- mand. The result is that different manufacturers implement their soft- ware in different ways, which means that to run different SCSI devices in the same PC, you'll probably need different SCSI adapters for each type of device. For example, if you install a SCSI hard disk, you should have no trouble adding a second hard disk. But if you wanted to add a CD-ROM drive, you'd probably have to inter- face it via a separate adapter card. and that defeats the purpose of a bus-type interface. Similarly, al- though it should be possible to un- plug an SCSI drive from your friend's Mac and plug it right into your PC, that type of compatibility is a long way off. By the way, that scenario is not as far-fetched as it may sound. Suppose you had prepared a long technical document in Ventura on a PC. and wanted to get it typeset. Most type- setting houses are Mac-based, so how do you transfer a 30-megabyte PostScript file of text and graphics in an efficient manner? However, SCSI compatibility is im- prwing. With the increasing spread of networks, high-speed high-capacity drives are becoming increasingly popular, and manufacturers are realiz- ing that they have to get off their prc»- prietary horses. It will undoubtedly take a few years for the dust to settle, but when it does, we'll all benefit. Micro polis To get a feel for real-world dif- ferences between the two competing standards, I examined a pair of what you might call fraternal twins made by Micropolis: the 1674-7 SCSI drive, and the 1654-7 ESDI drive. Each came as part of a "PC-F&k," which includes the drive, cables, mounting hardware, and partitioning software. The SCSI kit includes a host adapter, and the ESDI kit, a full controller; both have on-board floppy controllers, making each a plug-n-play replaces ment for a standard ST-506 setup. The SCSI setup also included drivers for Novell NetV\feiTe and SCO Xenix. Either drive has a formatted capacity of about 160 megabytes, and will co- exist vflth a standard ST-506 unit. 1 measured the performance of both drives under DOS using Core- test; results are shown in Table 1. along with comparative data for a standard ST- 251. All tests were run on a Del! System 300 CI 6-MHz 386 with 7 MB of RAM). Installing both drives is straightfor- vrard and well documented. In txjth cases, the controller/adapter card re- quires an 8K space in the upper mem- ory area; that space contains a BIOS extension that allows the drive to hook itself into DOS automatically. You must set several jumpers and switches that specify the BIOS ad- dress. IRQ, etc. Install the card, con- nect cables, power up, and ffy. 1 used each drive for several w/eeks with a variety of software (including many DOS programs and Windows 3-0) and hardware (including an inter- Model No. TABLE 1— COMPARATIVE PERFORMANCE Technotogy DTR Avg. (Kbyte/ Seek Time sec) Time (ms) m 1674 SCSI 508 7,6 4.3 m m 1654 ESDI 831 16.8 7.5 30 ST251 ST-506 243 44.3 6.8 CO ID o 87 1SSTP SU.9S For over 25 years, your most complete source for electronics books. An Absolutely No-Risk Guarantee. Membership Benefits * Bfg Savings, in addition to this introductory offer, you keep saving substantially with members' prices of up to 50% off tfie publishers' prices. * Bonus Books. Starting immediately, you will be eligible for our Bonus Book Plan, with savings of up to 80% off publishers' prices. • Club News Bulletins. 15 times per year you will receive the Book Club News, describing all the current selections — mains, alternates, extras — plus bonus offers and special sales, with scores of titles to choose from. • Automatic Ord«r. If you want the Main Selection, do noth- ing and it will be sent to you automatically. It you prefer another selection, or no txxik at all, simply indicate your choice on the re- ply form provided. You will have at least 10 days to decide. As a member, you agree to purchase at least 3 tiooks within the next 12 months and may resign at any time thereafter. * Ironclad No-flisJt Quarantee. If not satisfied with your t>ooks, return them within 10 days without obligation I • Exceptional Quality. All books are quality publishers' editions especially selected by our Editori- al Board. (PuWistwrj- Piicei Shwm) All txffiks are hardcover unless number is foWoweti l>y a "P" Iov paperbac^t. (Publishers' Prices Shown) ©1990 ELECTRONICS BCOK CLUB, Blua HWge Summit, PA 17Z94-OB10 Or Call Toll-Free 1-800-233-1128 To Join Today! EiECTRai^jcs Baah dm Blue Ridge Summit, PA 17294-0S1I) G YESI Please accept my membership in the Electronics Book Cijb and send the 5 volumes listed t>elow, plus my FREE copy of Delton T. Horn's All-Time Favorite Electronic Projects [3105P). billing me $4.95. H not satisfied, I may return the tiooks within ten days without obligation and have my memt>ership cancelled. I agree to purchase at least 3 tiooks at regular Club prices during the next 12 months and may resign any time Ihsreafter. A shipping^handllng charge and sales isx will be added tc all orders. Name Address City State Zip Phone Signature .^ Valid lor naw members only. Fwelg^ appllcanrs will receive special ordering Inslrucllons. Canada must r^mll In U.S. CLirrpncy. Ttiia order subjecl id a<:c«pt$nce by Ihe EI«DErontcs Qdok Clul>. RE11W m CO fn 3J CO (O o 91 nal modem and an Irwin external tape drive). I thought I had a problem with the tape drive, which interfaces via the floppy-disk controller, and the SCSI disk, but after much fiddling with switch and jumper settings to no avail, reinstalled the Irwin software, and everything worked fine, I think that in doing the mass-transfer of software from one machine to the other LapLink must have lost a bit along the way. Both drives are 5.25" units made by Micropolis, and are built like the proverbial brick outhouse, with die- cast aluminum frames, and use sur- face-mount technology. The interface cards are made by third parties, but appear to match the high quality of the drives. Based on my brief en- - counter I have to say I'm impressed with Micropolis. The products are easy to install, function well, are built well, and are documented well. PC-Pak versions of either the SCSI or the ESDI drive list for $1895; the drives list separately for $1470 and $1365, respectively I've seen the PC-Paks listed by reputable mail- order houses for less than $1200. ESDI or SCSI? Based on performance alone, it would be hard to choose either of the drives I looked at. The SCSI drive has faster seek time, but the ESDI drive has a better data transfer rate. Looking at the larger scheme of things, SCSI has much more poten- tial than ESDI, regarding both perfor- mance and expandability. Even though it's not possible at present to do the type of device sharing that is theoretically possible, there is in- creasing clamor from the market for that capability. ESDI disks are more common on the market, and seem to command slightly better prices. How- ever, disk-drive vendors can usually obtain SCSI units on request. In a few years, we should be able to connect multiple SCSI peripherals via a single interface card, but that may not be the card we would or could purchase now. However due to its performance and expansion potential, SCSI seems destined to earn an important spot in the PC landscape. Hard disk handbook Regardless of the type of hard disk you use, take a look at Alfred Glos- sbrenner's Hard Disk Handbook. It contains almost 800 pages of infor- mation on selecting and maintaining your hard disk, and it comes with two disks of public domain and shareware programs that help you maximize per- formance of not just your hard disk but your entire system. Topics cov- ered include selecting and purchas- ing a disk drive, installing it, adding a second drive, partitioning and format- ting, network considerations, back- up, security disaster prevention and recovery, and quite a bit more. The utilities include several ex- tremely useful programs: List, Cor- etest, several disk caches (made by Golden Bow Systems), several head- parking programs, PK2IP, several virus scan programs, a file- recovery (unerase) program, and numerous others that have been utility staples for years. If you're a beginning or in- termediate hard disk user, the Hard Disk Handbook can help you get much more out of your system. R-E AUDIO UPDATE continued from page 85 CO o z o EC H O LU O Q < DC There are times when magazines kill a report because in the editor's judgment the product suffers from a gross defect or a major flaw in its design. That policy has led many au- diophiles to complain that the compo- nents evaluated by most magazines always test good; the implication is that either problems have been glos- sed over or data has been falsified, My tongue-in-cheek answer to such complaints is that the products don't all test good, some of them test really excellent. Audiophile readers eager to learn the "real dirt" about hi-fi components are left unsatisfied when the dynamic range of product reports in the main- stream audio press extends only from merely okay to really excellent. That might be the reason for the prolifera- tion of underground audio magazines that purport to provide the straight scoop — for better or for worse — un- adulterated either by advertising pressures or the tnsensitivities of the reviewers in the mainstream audio test labs. Astrology, wine, and cars In my view, the reports in the au- diophile "tweek" magazines are neither as "truthful" nor as accurate as those found in the mainstream magazines^ — ^among which I include Consumer Reports. Reviewers who find sonic faults, major and minor, with virtually every electronic product that they evaluate are usually expres- sing their inner feelings, rather than objective truth. Inner feelings are fine, but are likely to be unreliable guides for critical buying decisions, par- ticularly when unsupported by careful lab tests. Despite the claims of the esoteric reviewers, their special hear- ing ability (and the product choices based on it) has never been validated by dozens of objective double- blind test procedures! Those who purport to hear ar- tifacts in audio components inaudible to ordinary mortals are likely to steer the unwitting reader toward the latest audiophile fads and follies. Audio ca- bles costing up to several hundred dollars a foot C!) and a variety of eso- teric components priced at perhaps ten times what their mainstream equivalents cost — these are typical of the product recommendations of the esoteric reviewers. In general, the talents of the under- ground press reviewers — and most mainstream British reviewers — seem to combine the approaches and at- titudes of wine tasters, astrologers, and sports-car enthusiasts. The faulty science of astnalogers and the unreliability of the wine tasters are well known, but the sports-car-buff approach is worth a few words. One can easily justify a love for fine ma- chinery, state-of-the-art engineer- ing,and the ability to go from to 60 mph in 50 milliseconds. In other words, along with the flash and the leather upholstery, your money buys special performance that can be both seen and measured. The super-expensive electronic components usually look beautiful and are carefully made with top quali- ty parts, but unfortunately for the true believers, they sound no better than most mass-prciduced products. If de- vout audiophiles derive special plea- sure from owning very expensive electronic components (and wires), they are certainly entitled to do so. But better sound — except possibly from the speakers — is not what they've bought, despite what the un- derground reviewers might have told them. R-E 92 Countersurveil lance Never before has so much professional infor mation on the art of detecting and eliminat- ing electronic snooping devices — and how to defend against experienced informa- tion thieves—been placed in one VMS video. If you are a Fortune 500 CEO, an executive in any hi-tech industry, or a novice seeking entry into an honor- able, rewarding field of work in countersurveillance, you must view this video presentation again and again. ORDER LINE— 1-800-522-6260 Wake up! You may be the victim of stolen words — precious ideas that would have made you very wealthy! Yes, profes- sionals, even rank amateurs, may be lis- tening to your most private con- versations. Wake r/p! If you are not the victim, then you arc surtounded by countless vic- tims who need your help if you know how to discover telephone taps, locate bugs, or "sweep" a room clean. There is a Thriving professional service steeped in high-tech techniques that you can become a part of! But first, you must know and understand Countersurveilance Technology. Your very first insight into this highly rewarding field is made possi- ble by a video VHS presentation that you cannot view on broadcast television, sat- ellite, or cable. It presents an informative program prepared by professionals in the field who know their indusrry, its tech- niques, kinks and loopholes. Men who can tell you more in 45 minutes in a straightforward, exclusive talk than was ever attempted before. known. The building had to be torn down in order to remove all the bugs. Foiling Information Thieves Discovet the targets professional snoopers seek out! The prey are stock brokers, arbitrage firms, manufacturers, high-tech companies, any competitive industry, or even small businnesses in the same community. Tlie valuable informa- tion they filch may be marketing strat- egies, customer lists, product formulas, manufacturing techniques, even adver- tising plans. Information thieves eaves- drop on court decisions, bidding information, financial data. The list is unlimited in the mind of man — -es- pecially if he is a thief! You know that the Russians secretly installed countless microphones in the concrete work of the American Embassy building in Moscow. They converted what was to be an embassy and private residence into the most sophisticated re- cording studio the world had ever Stolen Information The open taps from where the informa- tion pouts out may be from FAX's, com- puter communications, telephone calls, and everyday business meetings and lunchti me encounters. Businessmen need counselling on how to eliminate this in- formation drain. Basic telephone use cou- pled with the user's understanding that someone may be listening or recording vital data and information greatly reduces the opportunity for others to purloin meaningful information. The professional discussions seen on the TV screen in your home reveals how to detect and disable wiretaps, midget radio-frequency transmitters, and other bugs, plus when to use disinformation to confuse the unwanted listener, and the technique of voice sctambling telephone communications. In fact, do you know how to look for a bug, where to look for a bug, and what to do when you find it.'' Bugs of a very small size are easy to build and they can be placed quickly in a matter of seconds, in any object or room. Today you may have used a telephone handset that was bugged, it probably contained three bugs. One was a phony bug to fool you into believing you found a bug and secured the telephone. The sec- ond bug placates the investigator when he finds the real thing! And the thitd bug is found only by the professional, who continued to search just in case there wete more bugs. The professional is not without his tools. Special equipment has been de- signed so that the professional can sweep a room so that he can detect voice-acti- vated (VOX) and remote-activated bugs. Some of this equipment can be operated by novices, others require a trained coun- tersurveillance professional. The professionals viewed on your tele- vision screen reveal information on the -latest technological advances like, laset- beam snoopers that are installed hun- dreds of feet away from the room they snoop on. The professionals disclose that computers yield information too easily. This advertisement was not written by a countersurveillance professional, but by a beginner whose only experience came from viewing rhe video rape in the pri- vacy of his home, Aftet you review the video carefully and understand its con- tents, you have taken the first important step in either acquiring professional help with your surveillance problems, or you may very well consider a career as a coun- tersurveillance professional. The Dollars You Save To obtain the information contained in the video VHS cassette, you would attend a professional seminar costing 1350-750 and possibly pay hundreds of dollars more if you had to travel to a distant city to attend. Now, for only $49.95 (plus $4,00 P&H) you can view Coutitersiir- veillance Techniques at home and take refresher views often. To obtain your copy, complete the coupon below. RADIO- ELECTRONICS VIDEO OFFER RE 5(Kt-B Bf-County Dlvtl. pjrminRitilt. NY 117 ^ Mk-jsc rush rn ^ cop)- of I hi- Countt-rsurvci 1 1 jncc- TL"t h fiiqu(.-& ViiJcij VHS Cassmc for J-1y.y5 plujS4 0[J for pi>sra(;t-and hiintiliiij^. Ha. uf Cassft[« of ik-rvd Amuunt of paymirnt %. BUI my P VISA D MMt«Cird drd No. _ EKpire Dire _ ./. Si^niMurc Niirnt Atldrtss Ciry All paymcnu in U.S.A. ^nds. Quiudmnj jdd $4.UU per VHS cassette. No fsjrtrij;n onJcri. Ni-w Vbrii StarL' rcsidents^ ■aM jppliciblii' S3 Its tax. . State .. .ZIP. CALL TODAY TO ORDER 1-800-522-6260 S m m: J} a> to o 93 SWITCHABLE SCOPE PROBE ONLY ■ 3 POSITION SWITCH IX, 10X, REF. ■ COMPENSATION FOR ALL SCOPES ■ SNAP ON ROTATING GROUND ' SATISFACTION GUARANTEED ' REPUCEABLE TIP $89 KIT $35 TOLL FREE _(800) 772-1519 FREE CATALOG OF TEST LEAD KITS & ACCESSORIES CALL FOR NEAREST OISTRIBUTOR UODEL ATTEN. BWMhtz AT-3DB LENGTH FT. M RESETIUE PF Uil PRICE 4101 SwilchBbte Ix^tDxi'n 15/2DD 4 1.2 25/1.4 65^14 ino HSM 41 Q3 1x 25 4 t.2 1.4 45 1 3C.O0 41 04 1DJ{ £00 4 1.2 1.4 14 10 33.00 4^10 1Q0X 250 4 1..2 1.4 7 100 49,00 4115 MASTER KIT (NCL. 1 e A. 41 01 , 41 03, & 41 04 Bg.oo , e PROBE m. MASTER 4898 RONSON CI, SAN DIEGD, CA 9Zin FAX (B19) 5G0-T3S4 CIRCLE 197 ON FREE INFORMATION CARD Try the ileBtranlGS bulletin board system (RE-BBS) 516-293-2283 Tlie moie you use it llle more useful it becomes. We support 300 and 1200 baud operation. Pai^meters: 8N1 (S data bits, na parity, t stop tit) or TE1 {T data bits, even parity, 1 sto|) lilt). Add youfsell to ovr user liles to increase your access. CDmmiinicate with other R-E readers. Leave your cnmrrents an H-E with the SrSOR RE-BBS 516-293-2283 with over 24,000 industrial electronic components and will. . . g)ip your <>rder today ill?: -P Colt or Writ©,.. ■ "*i| p00i992-9943i CO o z o LU _l m Q < 94 "^ ^S\lt3 $79.06. We stiip C.O.D. Free catalog, ACE PRODUCTS, PO Bsx 582, Dept. E, Saco, ME 04972. 1 (808) 234-0726. TUBES Sylvania 6LQ6, 6L6GC, 20LF6 etc. Huge discounts. ARLEN SUPPLY, 7409 West Chester Pike, Upper Darby, PA 19082. 1 (800) 458-1301, PHOTO FACT folders under #14G0 $4,00. Others $6.00. Postpaid. LOEB, 414 Chestnut Lane, East Meadow, NY 11554, CLASSIRED AD ORDER FORM To run your own classified 3d, put one word qn eacti of ttie lines lielow and send Uii$ fonn along wHti your ctieolt tO: Radio-Etectronics Classified Ads, 500-B Bi-County Boulevard, Farmingdale, NY 11735 PLEASE INDICATE in whicti category of classified advertising you wish your ad to appear. 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Copy to be in our hands on the 10th of the third nvonth precedii^ the date of the issue, (i.e., Aug. issue copy must be received by May 10th). When norrrral closing date falls on Saturday, Sunday of Holiday, issue doses on preceding working day. Send for the classified brotJiure. Circle Number 49 on the Free Information Card. 96 COMMUNICATIONS/Electronic equipment sales, service, FCC licensed, Catalog $1.00, RAYS, PO Box 14862, Fort Worth, 7X76117-0862. CONVERTERS atl major brands. Info & orders 1 (800) 782-0552. FREWAY, INC., SMP P0# 5036, Bumswilte. MN 55337. No MN sales. FREE catalog. Interfaces for IBM compatlbtes. Dig- ital I/O and analog input. Control relays, mdors, ligftts, measure temperature, voltage. JOHN BELL ENGINEERING, INC., 400 Oxford Way. Belmont, CA 94002. (415) 592-8411 CABLE descramWers (Jer roW) from S40.00. Tocom VIP test ctiip- Fully activales unit. Also Zenitti test board. Fulty activates Z-Tacs. $50-00. Call (213) 867-OOai. FREE CATALOG FAMOUS "FIRESTIK" BRAND CB ANTENNAS AND ACCESSORIES. QUALITY PRODUCTS FOR THE SERIOUS Ce'er. SINCE 1962 FIRESTIK ANTENNA COMPANY 2614 EAST ADAMS PHOENIX. ARIZONA 85034 $1.99 software for IBM Compatibles. Ouality at af- fordable prices! Huge selection: business, games, graphics, utilities, database, spreadsheets. Free catalog, AULT, 1556 Hatford Avenue, #242, Santa Clara, CA 95051. ROBOTICS software, PC/MS[X)S. Explore com- putet vision, sonar sensing. Free brochure. ROBOTS ETC., Box 122, Tempe. AZ 85280. TOCOM 5503 VIP 'tumon" module. All channels. $39.00. Inforniation, schematic S5.00. MIKE, Box 743, Olds mar, FL 34677. IS it true Jeeps for $44.00 through the U.S. Gov't? Call for fads! (504J 649-5745 ExI. S-5192. Quality Microwave TV ftnlennas r WnOESS OBLi - FIX - !«■» - A wi lli r TV I UDn Mlk eata i»»M • TbmMi t.t H ZJ SB. . 3e-CtEnncl Syslnr Ciim|i4elE 1143.95 • 12-aannel Systnn ConjUltt SI HS& . CjI or miill ISASE) te "HH" CjBtou [ PMilPS-TECH ELKTHMHCt I rJL Im 1533 - ScrtttOI*, U §5252 \fkrmi {BtH^tn-Tnt [km Cnmm^timmtmt) WARRANTY llBlBCirt .*1» • COO'I " ^- PHIMTED circuit t>oards etched & drilled. Free deliv- ery. K« FELECTRONICS, INC., 33041 Grt>esbeck, Fraser, Ml 48026. [313) 294-B720. LASERS, tmw to 2kw, worlds largest selection of new & used surplus. Free catalog. MWK INDUS- TRIES, 1269 Ponnona Ftoad, Corona, CA 91720. (714) 278-0563 PROFESSIONAL PC board layout. Fast delivery. Gerber.E5(cellon,$.80upperpin.MR.JOHNSON,1 (800) 359-0466. 7 «•«[« -^ -k PRESENTING « -K «« « CABLE TV T -k-k-k-lt-k STARBtftKi ***** mmOLD, HAMUN, OAK AND Q7HER FAMOUS HANUf ACTURCRS « FMBT WWRANt^ ^IKXiA^M >-543-43J(» MCM ELECTRONICS 65Q CONGRESS PARK DR CENTERVILLe. OH 45.<159-407S A PREMIER Company SOURCE NO. HE-67 CIRCLE S7 ON FREE INFORMATION CARD Z s rrt CO 8 lU5 450ns 4S0n5 450ns t25v) 350ns {26v) 450ns 450ns (25V-CMOS) 450ns (25v| 200ns (21v| 2S0ns (21 ¥| 450I1S (21V) 450ns (25v) 450ns (25y-0nfi Time Progfammatle] 45Dns {25V.CMOS) 2O0ns(21v) 260ns i2iv} 200ns (12.5VI 250ns (12.SV) 250ns (2Sv) 250ns {21U-CMOS) 8 2D0ns(21v) S 250ns |2U) 8 250n5t21v) 8 25ans(21v) 8 200ns (12,5v) S2S0ns (12.5v| 8 250ns (12.5V-CMOSI a20an5 (12.5V) 8 250ns(12,Sv) 8 250ns(12.5v.CMOS) 8 2O0ns (12 5V-CMOS) 450ns 460ns iUNICORN eli<:tronic5 3,99 3,79 341 649 6,1? 5,55 3.99 3.79 341 3.29 3,13 282 3.79 3.60 3,24 6.29 S.9B 538 3.99 3.79 341 3.79 3.60 3.2* 3.79 3.6C 3.24 3.69 3.51 3.16 3.19 3.03 2.73 5.79 5,50 4.95 1.99 1,89 1.70 4.19 3,98 3.68 3.99 379 3.41 3.79 3,60 3.24 399 3.79 341 3.29 3.13 2.82 6.79 6.45 581 4.19 3.98 3.58 5.79 5.50 495 S.09 4.84 435 5.79 5,50 4.95 5.79 6.50 4.95 529 6.03 453 4.79 455 4.09 6.29 5.03 4.53 749 712 641 6,99 6.64 5.98 6.99 6.64 5.98 17.99 17.09 IS, 38 13.99 13.29 11,96 14.99 14.24 12.82 1 001 Canoga Ave.. Ural B-8 • Chatswortti. CA 91 31 1 OUTSIDE CALIFORNIA: (800) 824-3432 (Orders Only) IN CALIFORNIA: (818 341-8833 ORDER BY FAX: (818) 998-7975 Minimum Order: 515.00 DO m i o 99 CIRCLE laO ON FREE INFORMATION CARD CABLE TV EQUIPMENT Converters, Remote Controls, Descramblers, CD Players. JERROLD-OAK-SCIENTmC ATLANTA-IIAMLIN ZENITH MANY MORE CALL TODAY; V Only quality products sold v Easy to use VSjitiffacdon guaranteed v Knowiedgeable sales Xlaff V Most orders shipped within 24 hours CALL FOR YOUR FREE CATALOG 1-800-228-7404H MAKE THE CO^fNECTION WITH NU-TEK ELECTRONICS II 511 4 Balcones Wood Dr,#307 Depl.298 ^^^Ausuii^X^875^^^^^ LIFE is worth saving. Innovative new automotive device causes brake liglits to flash rapidly oniy in the event ot very quick stop, warring cars behind you and reducing the risk of fear end collisions Simple 3 wire installation. Plans only $9.95. NEW SOLU- TIONS, Box 321, Dept. R1. Omaha, NE 68010. BUSINESS OPPORTUNITIES EASY work! Excellenl payf Assemble products at home. Call for information. (504) 641-8003 Ext. S192. MAKE S50/hr working evenings or weekends in your own electronics business. Send for free facts. INDUSTRY, Box 531. Bronx, NY 10461-0208. YOUR own radio station! AM, Ff^fl, TV, cable. Li- censed/unlicensed. BROADCASTING, Box 130- F11, Paradise, C A 95967. INVENTORS: We submit ideas to industry. Find out whai we can do lor you, 1 (800) 288- IDEA. LET the government finance your small business. Grants.' loans to SSOO.OOO. Free recorded message: (707) 449-8600. (KS1). TUBES - 2000 TYPES DISCOUNT PRICES! Eariy, hard-lo-iintJ. and modem lutjes. Also transformers, capacitors and parts for tube equipment. Semi $2.00 for 28 page wholesale catalog. ANTIQUE ELECTRONIC SUPPLY 688 W. First Sl.'Tempe, A2 85281 •S02»894-9503 LEARN to cleani'iepair fax machines. Huge new market! Earn $85.' hour No experience necessary. Free details call 1 (800) 537-0589 or write to: VIE JO PUBLICATIONS, 5329 Fountain Ave. #310, Dept. FX200, LA, CA 90029. MAKE 575,000 lo $250,000 yearly or mors fixing IBM color monitors (and most brands). No invest- ment. Start doing It from your home. (A telephone required.) information, USA, Canada SI. 00 cash. US funds. Other countries $8,00 RANDALL DIS- PLAY, Box 2168-R, Van Nuys, CA 91404 USA. PROJECTION TV... Make SSS's assembling proj- ectors Easy!.,. Results comparable lo $2,500 proj- ectors... Plans, 8" lens & dealers information $25.50... Professional systems available... Illus- Irated catalog free. MACROCOMA, 15GCX Main Street, Washington Crossing, PA 18977... Credit- card orders 24Hrs. (215) 736-2880. ANTIQUE RADIO CLASSIFIED Free Sample! Antique Radio's r^**' Largest Circulation Monthly. |^J^^ Articles, Ads & Classifieds. 6-Monlh Trial: S13. 1-Yr: $24 {$36-1 st Class). A.R.C., P.O. Box 802-L6, Carlisle, MA 01741 MICROWAVE oven testing earns ready money, complete business plan including insinjction, bro- chures, fliers, and more S6.50. Microwave leakage meter $19.50. SE JUDGE INDUSTRIES, 3035 Radford Drive, Indianapolis, IN 46226. SATELLITE TV VIDEOCIPHER II manuals. Volume 1 - Hardware, Volume 2 - Software - either $34.95 Volume 3 - Projects 'Software, Volume S - Documentation or Volume 6 - Experimentation $44,95 each. Volume 4-Repalr$99.95.Volume7-032''Hacklng$54.95. Cable Hacker's Bible - $34.95. Clone Hacker's Bible - $34.95. Catalog - $3.00. CODs (602) 782-2316. TELECODE, PO Box 6426.RE, Yuma, AZ 85366-6426. SATELLITE monthly audio codes 1 (900) HOT- SHOT intended for testing only $3.50 per call. SCRAM BUNG NEWS FuEure aitic^ [his monDi *£□ y-chi Wjm 10 S^\ descramblers" ir&tifEf reporr incJudES Uiit whDk£jle u^irces. in's-and-jtirts. praliiabiMy etc SuirscTlpLan' S19.95.Vr. The PavTVand Salelhl tPescrambUna series lus ^urn-ons. by- pasMS. indliwltf*y(Hir-owi pr^GiMi^ior ri2.si systents. ycliuruU lEhf Da> Sf{:aMBSijniU2a[I£|fJUCLri3. $1d95caEn WutiHS Cable Descramblinp S9.95. atflldSatfifllle Systems Unftei S600. S12 95 An^ 3.'S29 or ^'Si2. All new (dialog $1 or caW. Strmmnq News, 1552 Hsrfel Me., mi, SullalD, NY, 1421G. COB'S ate OK, |T16)S74-ZI]«3 0> O z o IT t3 ill O Q < 100 Paper cone with gold lone dust cap. S oz. magnet. 8 otim. t/2' feno lluid vptce coil. Fewer harvdling: BOW RMS, 70W max. Ffe<(uency re- sponse! 3K-20KHZ #RM-271-020 \^ $1«$1"95c SUPER HORN TWEETER Original piezo tweeter made by Motorola. SPU94dS2.B3Vnt $5=" $4=° $3"* il-9j i*D-7SiJ |M uflj 2" DOME MIDRANGE Tentile cfome midfange made Py Philips. B ohm. SPugodB 1W/1M. sow RMS, 40W max. Response r 5S0-5KHZ #RM-2SO-210 15" SUBWOOFER Oual voice coil. "lO oz. maQn©!. 6 ohm imp, 100W RMS. UOWmax. Response: 20-1. 2KHz. Resonant frequency: 2 1Hz. SPL=93dBlWnM- #RM-29O-190 $54" $A^ Ll-3|i l*-iip) SUBWOOFER XOVER ^OQW RMS crossover designed spedficaDy for use with dual voice coil sub woofefS- 12 dB per octave roll-oK at 150Hz. 10" POLY WOOFER #RM-260-220 $28"* $24« 3*0 E. Firfil SL. Da^kn, Ohio 45402 Local: ^'^13'£££-01 73 FAX:5l3-2£2'4e44 ' 1 5 (iay rwyyey b&a>. duarant&S' ■ $1 $.CQ mlnimuim order * W« accept Maslercafd, Visa, DIscovsTk ^nti C.O.D. Of'ders. ■ 24 Ixjur ^hipping - S^bpping c)iarg« = UPS chart fste + 11.00(53.00 minimufn chargcf) * Hours &;30 am- 7,00 pm EST, Monday - Fridav ■ Wail order cusEom- ers. pteasc call Tor £hipp4r>g QsCinnatQ {>n ardors exceeding 5 lbs. Foreign customers ple&se MnO S5-00 U.S. funds Por cacaiof] postagfl- 12" CAST FRAME WOOFER #RM~290-096 TITANIUM COMPOSITE TWEETER Tfie advantages of botti hard and soK dome teclinotogies. 8 ohm. Fsrro fluid cooled voice coil. SPL=90dB rw/1M 50W RMS, 70W max. 4" round. Poiydax #DTW100T125. #RM-27(WM7 12" woofer made in the USA by Eminence Paper cone and dust cap with treated cloth surround. BO oz. magnet. 2-1/2' vented voice coil 8 otifT. 170W RMS, 235W maji. 40-4.5KHZ response. #RM-290-147 SPEAKER BUILDING BOOK Revised edition oi David Weerns' best seElifig book. Leam to build low cosi speakers that rival the high priced modets, #RM-50CK)21 § $16* CALL TOLL FREE 1-800-338-0531 CIRCLE 56 ON FREE INFORMATION CARD FREE catalog — Lowest prices worldwide, save 40 — 60%. Systems, upgrades, parts, all major brands factory fresh and warrantied. SKYVISION, 2009 Collegeway, Fergus Falls, MN 56537. 1 (800) 334-6455. CABLE TV secrets — the outlaw publication the cable companies tried to ban. HBO. tvlovie Channel, Showtime, descramljlers, converters, etc. Sup- pliers list included. S9.9S. CABLE FACTS, Box 711- H, Palaskala. OH 43602. VIOEOCYPHER II descrambling manual. Sche- matics, video and audio. Eisplains DES, EPROM, Clone Master. 3 Musketeer, Ray-per-view (HBO, Cin- emax, Sliowtime, adult, elc.) S16.95, $2.00 postage. Collection o( software to copy and alter EPRCjM codes, S25.00. CABLETRONICS, Box 30502R, Bethesda, MD 20824. CABLE DESCRAMBLERS OAK M3SB COMBO S3S.SS Jerrold, Zenith, Hamlin, Sci. Atlanta, Pioneer & MOREf OUR PRICES ARE BELOW WHOLESALE! CABLEH- PLUS 14417 Chase St *4ei-A Panorama Cily. CA 91402 1-800-822-9955 • Other Info. 1-81B-785-4500 NO CAIIF. SALES - DEALEFB WANTED EDUCATION & INSTRUCTION MAGIC! Four illustrated lessons plus inside infor- mation shows you how. We provide almost 50 tricks including equipment for four professional effects. You get a binder to keep tlie materials in, and a one- year membership in the International Performing Magicians with a plastic membership card Ihat has your name go Id-em Imssed. You get a one-year sub- scription to our quarterly newsletter "IT'S MAGIC!" Ordernow!$29.95foreachcourse-t-$3.50 postag e and handling. (New York residents add applicable state and local sales tax). THE MAGIC COURSE, 500-B BiCounty Boulevard. Farmingdale, NY 11735. CABLE TV DESCRAMBLER LIQUIDATION! Major Makes & Models! Will match or beat anyone's prices! Dealer discounts at 5 units! Examples: HAMLIN COMBOS . $44 ea. (Min. 5) OAK ADD/ON $40 ea. (Min. 5) OAK M35B $60 ea. (Min, 5) WEST COAST ELECTRONICS For Information: 818-709-1758 Catalogs & Orders: 800-628-9656 F.C.C. Commercial General Radiotelephone license. Electronics home study FasI, inexpensive! -Free" details. COMMAND, D-176, Box 2824, San Francisco, CA 94126. LEARN IBM PC assembly language. 80 pro- grams. Disk $5.00. Book $18.00. 2IPFAST, Box 12238, Lexington, KY40S81-2238. WANTED INVENTORS! Contused? Need help' Call IMPAC lor free information package. In US and Canada; 1 (800) 225-5SO0. INVENTIONS/new products/ideas wanted: call TLCI for free information 1 (300) 468-7200 24 hours/ day - USA'Canada HEWLETT Packard G-382A variable attenuators. Any condition K6G0X, Box 10, O'Neals, CA 93645. (209) 368-3548 collect. CABLE TV DESCRAMBLERS 10 Lai ,„ Ml JliRROLO™ SB-3 OR 2 S89.00 Mi.OO ^ > — 1^ IlmriirMU)-1200. S99,95 1(52,00 Z 2 ? _ 0«liN-12W^J S99,95 S62.0O O < ^ Ojk-M-35-B W/V.S J99.O0 )78.00 EC T ^ ?S OAKE-n J99.95 SS8.00 l~ O t^ S2 Zenith ES AVI.. S185.00 SUS.OO O |_ il^ ^ Eig]cPD3 _. SI 20.00 185.00 Ifj < t ^ sdcniLnc Ati«ti«-™,„ Si».95 Jios.oo m S Fh ^ SA-Comba'l..-™™. CALL JCill . _I t^ X Tpciin-... „„. JiSO.tJO S29S.0Q Q d ^ f- OikN.12W/AuIo 11 40 ,00 SI 05.00 2 5 < ^ tcrrrilri Surmm CSV.... S13il.95 Cill *NEW STARGATE 2000 CABLE CONVERTER 1489.00 10-$69.00 100-Call Last cinannel recall -Favorite channel select- 75 channel-Channel scan-Manual fine tune- One year warranty-surge protection-HRC S Stand- ard swiichable- and much more Cflll Todnv! INFORMATION(402}554-041 7 Orcjers Call Toll Free 1-800-624-1150 M.D. EI.ECTRONICS 643 NORTH 98TH ST. SUITE 133 OMAHA, NE, 68114 cm CLE 53 ON FREE INFORMATION CARD MARK V ELECTRONICS, INC. t"(nii|]etiti\e I*ricin Metal Cabinei + Tianslomner TA-3600 LG-1935 #007 TA-477 LG-19Z5 #003 TA-802 LG-1924 #001 TA-IOOOA LG-1924 #001 Kit Set Assmb. Set S 138.60 $160.20 $115.20 $ 130.50 J 91.75 $10J.15 S 104.12 $ 122,92 ▲ Beginner AA Intermediate AAA Advanced • SM-328 '"Special' Price Que ED this specul oiler A low price, ws can only exchange or fepair any cpl Etiese untts 1TA.360I3. TAjf77. Ik-mi 8 TA-IOOOA) wiinin IS days 01 yout reMW rhe al»ve pricas afe lor the cafhp3et« »ts. For ?«pafatft unit pnce, please so« below. Transtormef W ^ *j -^ TA-477 ^^ Metal Cabinel t Fully Assembled S 139.00 speajC $j*ea3 AMPLIFIERS iUT ASSMB7 MODEL TA-2eMK2 TA-50A;B TA-50C TA-120MK2 TA-300 TA.a02 TA-323A TA.377A TA-aoo TA.477 TA-8O0 TA-802 TA-320A TA-IOOOA TA-1500 TA-22aO TA-2400A TA-ZSOO TA-2800 TA-3000 TA-3600 DESCRIPTION Digttal Voice Memo AA S 30.00 Multl -Purpose Melcc^y C^neralor A. Multi-Purpose Melody Generalet A. 35W Class "A^ Main Power Mono Amp i 12.84 13,S5 29.60 20.00 SOW Mulli-Pufpose Single Channel Amp A 60W Stereo Power Booster 1w/casel AA -,,-. 30Wx5 stereo Pre-main ;^rnp A .....^ 29.50 H(-Ouallty FET Stereo Pre-Amp AAA, ,„ .„^.„...... 59.95 JOW Solid State Mono Amp A ,.,.. 29.00 12QW Mosfel Power Mono Amp.AA, ..,„„„„„..,., SftOQ SOWtSOW DC Pre-Mam a Power Amp AA 60.92 SOW-fraOW DC stereo Main Power Amp AA- -.....,..-..„,.,„.,._ 45. 9t 60W.60W OCL DC Pre-Main Stereo Amp AA 40.39 10QW Dynamic Class *A"Maln Power Mono Amp AA- .. 59.69 i00Wx2 Class -A- DC Stereo Pre Mam Amp AAA 73.70 PET Superclass "A" DC Pre-Amp AAA 47.70 Electronic Echo & Revertteralton Amp AAA* HO Pre-Arnp. w.'10 tiand graphic equalizer * Hl-FET IG Pre-Amp w(3way lone conlrol AA 48.90 Slereo Simulalor (rTMir>o TV / any mono source} AA 27.00 300W HQ Hi-Fi Power Mono Amp AAA 79.00 POWER SUPPLIES KIT % 1 ?.20 18.71 39 .ao 29.00 70.00 39.35 75.00 34 93 85 00 79.20 59.72 49.37 B0 5B 9581 58 24 96.00 6S.eo 63.67 38 SO 103.00 MlSCKLLAfJETSBg TA-3S00 MODEL TY-23B TY-25 TY-3S TY-36 TY-3S TY-41MKV TY-42 TY-43 TY-45 rf -47 SM-222 SM.328 SM333 SM-666 KIT ASS^tB, DESCRIPTION 3 Channel Color Lighl Conuollei AAA* % 51.20 % 65.00 Stereo Loudspeaker Protector A , 13.85 1 9.a5 FM Wireless Microphone 1022 ACaDC Ouarti Digiial Clock A , 1 9.00 2620 Sound/Touch Conlrol Switch A 12.00 Inlared Remote Conlrol Unit w/case AAA „ 20.00 35.00 Bar/tlol Level Meter AA 24.15 3'.* Digital Panel Meier A _ 29.00 38.00 20SlepsBar.'OolAudioLe«elDisplayAA 39.45 46.14 Superior Eleolronlc Houlelle AA ..,.„„„.,„„.,w 19.46 27.24 7 Band Hl.FI Graphic Eoualiier AAA 26.80 38.90 4 Channel Prolesslonal Color Lighl Controller*. .-. -,..„.. 139.00 Audio'Video Surround Sound Processor AAA* , 62.00 70-00 34.00 TR-100A TR-355A TH-35SB TR-503 SM-43 SM-48 SM-4SA SM-49 SM-100 FC-IOOOA 0-1 6V2A Regulated DC Power Supply (w.'case) AAA % 0-15V 5A Regulated DC Power Supply A 14.55 O-30V 3A Regulated DC Power Supply A 14.66 O-50V 3A Regulated DC Power Supply AA 1S.75 S'-iMuJli-FurK^tJonal LedD.P.M [w/ABS piaslKcase] AA % 3^.50 4i;-J-li-PrecisionDPM.AAA. .. 38,00 4'.'i Hi-PresctSH3n D.P.M. {Wi'ABS plastic case) AAA 41.20 3'^ MuKi- Functional LCD D.P.M (w.'Tiolcl runclion) AA 36.00 150 MC Digital Frequancy Counter AAA 7^00 1 GHz Frgquency dounl&r * : D OOBti COD M 4 $5 DO \Xr:i S 69.60 20.76 20.76 22.65 AS5M6. MODEL LIS- 1273 LG-t694 LG-1924 LG-1926 LG-19B3 Dynamic Noise Reduction A 26.00 METaL CAblNETS WffH AUfMiNt-iM PANEIT W" y D" MATCHING PRICE 12" 7- TA-2aOD,TA-377A. TA-2200 $ 22.16 16" 8" TA.323A. TA-377A, TA-2200 26.64 ir IIW TA-803,TA-820A.TA-l500,TA-l2IlMK2.TA-BOO.TA-10t»A32.00 19" 11H" TA.477.TA.800. TA-1 500. TA-tOOOA. TA-3600 35.00 tg- 8- TA-377A, TA-2SO0. TA-220O. TA-120MK 2 28.50 S 43.00 48,00 52 00 44 50 90.00 1 79.00 MODEL «aoi «O02 #003 »004 #005 »006 #007 DESCRIPTION 56VCT. 60VCT 6A 72VCT 3A 80VCT6A 4eVCT 6A 52VCT 3A 36VCT 5A POWER TRANSFORMERS f uPS Ij-Ou^ '*«• US .>»w S3 CO ' If (f Va'urrw d'lCEIulit Jit ^itai* u(»~ ' MATCHING PRICE TA-8Q0. TA-B02. TAa20A. TA-IOOOA. TA-1S00 S 26.00 TP-503, TA-323A, TA-400 ,TA-30O 2100 TA-477 _ 2700 TA- 120 MK 2 „_.„,...„..„.„ . __. ,. 21 .00 TR-355B 1 5.00 TR.365A 14.50 TA-3e00 '-^OO Busmess 6 Snowroom hours iPatifH; Time! Men iriru Fn, 9 3D am to 5Q0 pm !■*:'■«-■ 13' «"-i.two'ttw(]r*r.M'.r-.-.- Sal. 10 QOam lo 5 OO pm MARK V ELECTRONICS, INC. - 8019 E. Slauson Ave, Mqnrebello, CA 90640 ii==JH[H; CIRCLE 93 ON FREE INFORMATION CARD O < m CD m CO (D O 101 CONSOLIDATED THE ULTIMATE ELECTRONICS CATALOG Order your 260 pa^ caUloff and price Utt with over 14,000 money taving filectntnie partj and equipmanti Send $3.00 in a checit or monoy ofder, oe call 1-S0a-S43-356S today and me your MaitGKaid 01 Vila. ConBolidated UlectronicB^ Incorpofatod 705 Watervliet Ave., Dayton, Ohio 45420-2S99 Add»ai_ City _8t^e_ _Zip_ CIRCLE 70 ON FREE INFORMATION CARD COMPUTERS FOR LE$$ JC1 10 MHz 8088 System $ 399.00 • 10 MI-lz Motherboard w/M(KB RAW • Math Co-Processor Socket • One 5.23' 3«l KB FlopijyJi Controller • lOMC^Erbanoedfciytxjard • ISO Watt Power Supp^ & Case • MonoGraphlcs Card w/ Parallel Port • 12r Amber MonDchrwne Monitor JC! Standard Configuration: • 1 MB RAM on board Wait State • Built-in Real Time Clocks Calendar • Math Co-Processor Socket • One 1.2MB or 1.44 MB Floppy Drive • 1:1 Hard/ Floppy Diittl^ntroller • 2 Serial, 1 Parallel, and 1 Game Port • 101-Key Enhanced Keyboard • Deluw Case w/ 200 Wa tl Power Supply • MonoGraphicfl Card w/ Parallel Port • 12" Amber Monochroaje Monitor JC! 12 MHz 80286 System $649.00 JC! 16 MHz 386SX System $ 869,00 JCI 20 MHz 80386 System $ 1 149.00 JCI 25 MHz 386 32K Cache $ 1495.00 JCI 33 MHz 386 32K Caciie $ 1850.00 Pleas* Call Fof Custom Conflgu rations One Ysar Pads & Lat>or Warranty 30 Day Satisfaction Guaranloe Shipping & Handling Exira VISA Jt M/C add 3% Aii^ex add 4% JINGO COMPUTERS INC. 5122 Walnut Grove Avenue San Gabriel, CA 91 776 Tel: (81 8) 309-1 1 08 - Fax: (81 8) 309-1 1 07 CABLE T.V. CONVERTERS WHY PAY A HIGH MONTHLY FEE? All Jerrold, Oak, Hamlin, Zenitfi, Scientific Atlanta, Magnavox and all specialized cable equipment available for shipment within 24 hours. Forfast service MC/ VISA or CO. D. telephone orders accepted (800) 648-3030 60 Day Guarantee (Quantity Discounts) 8 A.M. to 5 P.M. C.S.T. CLOSED WEEK- ENDS. Send self-addressed Stamped enve- lope (60e postage) for Catalog. INVENTORS INVENTORS! Can you patent and profit from your idea? Call AMERICAN INVENTORS CORPORA- TION for free information. Over a decade of service 1 (BOO) 338-5656. In Massachusetts or Canada call [413) 568-3753. For under $500 No installation \ Jlist plug in and turn on. For data write: Video Magic 151A Vereli Street Farmingdale, NY 1t73S CABLE BOX REPAIR JERROLD 400 opportunity CATV repair manual.. DRX-3DiC-105 cable converter CAD drawings., cir- cuit schematics, microprocessor pinout... parts list, parts available S14.95 -i- S2.00 P&H.. rush US PC money order, cash or check to .. BONDED CABLE T.V. CO. **• Ph. (313) 548-0050.. PC Box 20340 Dept. RM ' fax (313) 548-0053.. Ferndale, Hfll 43220-9998 U.S.A. "* no COD... Cable TV Descramblers If you find a better deal, Mje'W better our deal, 'Jorrold 'Jocom 'Hamlin 'Scientific Aiianta ^ Oak 'Zenith Ask about our extended warronty program. COD, Visa, M/C welcome. Free Coll - Free Catalog. Video Tech 800-562-6884 3702 S. Virginia St„ Ste, 160-304 Reno, NV 89502. BUY BONDS ZENITHS & TOCOMS SUPER Zenith (Z-TAC) converters (f!asi>- lRg)...$169,(K>. Zenith "turn-on" module... J49. 00. Tocom SSa4's...$139.00. Tocom (add-on) de- scramblers... S69.00. Tocom (5S03-VIP & 5507) ■'turn-on" chips,. .S49.00. CINEPLEX VIDEO GROUP- 1 (800) 728-4627. MASTERCARD AND VISA are now accepted for payment of your advertising. Simply complete the form on the first page of the Market Center and we will bill. THIS A REGULAR TYPE BOLDFACE AD with a tint screen. To have yourad appear lihe this one, the cost is S4.1S per word. FREE CATALOG! 1-800-648-7938 For all information 1-702-362-9026 JERROLD HAMLIN OAK ETC. CABLE TV DESCRAMBLERS ■ Compare our low Low Retail Prices! • Guaranteed Prices & Warranties! * Orders Stiipped Immediately! REPUBLIC CABLE PRODUCTS INC. 4Q3Q Paradise Rd. #15 Depl. HE-9a ' Las Vegas, NV 89109 — -' t^hdp America;, ^ prepare for Support Ameiica''s colleges- Because college is more than a place where young people are preparing for their future. It's where America — and American business — is preparing for its future. Give to the college of your choice. .!££ 102 CIRCLE 179 ON FREE INFORMATION CARD QUALITY PARTS • DISCOUNT PRICES • FAST SHIPPING (MiMmsm^^^m^ DfGITAL CLOCK AND APPLIANCE TIMER Digtml deck and appliance timer removed frofn auEomatic electric coHes makers due 10 design changes. Operates r^ on 120 Vac and fe capable of turning on appliances drawing up to 10 arr^s. Because ol the application Ehey were designed for they automatically turn ofl after two hours. Some have surface blemishes. 4.2" X 2.45' X t.rdeep. Beige Of h/orywilh brown trin\ CAT* IMCT S6.50 each 12 VDC GEARHEAD MOTOR =n9 beep followed b^ a tow squeldi^ all LEDs shut olf and the unit stap«. Unit requires a 9 voll |ransi$tor batlery (not induded) to operate. CAT*TMf?'1 $2.25eiich ' 10 fof S30.00 SWITCHES SPOT PUSHBUTTON Marqufif^lJ 1543 Rated & amps <^ 125/2SC Vac. Black plasisc pushbutton. Switch body: .ft2r X M' X .65' CATiPB-IB Si.eSaH * lOforSl^.OO PUSHBUTTON SWITCH a GC/Thsrnien* 35 420 (Q S.P.S.T. normaiy (^t«n rnDmentory pT pu^tibutton (wijch. R*d pLattic yj actuator 0.57" diameter Chronw twz&l 0. &S' di Bm«t«r. Th r»ad«d bu sfimg rriounikin .50^' diametw hole. R«t*d 3 Amp (^ 250Vac. Sobfar loop tarrnnats. CAT«PB'20 (1.00 each THUMBWHEEL SWITCH 1 pole 10 position jq ii pn^ dAcimaPancDded | %. l^vv !['*V »witch«s MiJiich interlock to nwke up dssi red number _ or digits. Tarminates to 11 pc pint [\ com' mon and 1C poles). Each udion ni»afturum CA T« H T5-4 PC $1 00 each i WALL TRANSFORMERS:;;; AIX PLUG DIRECTLY INTO 120 VAC OOTLST eVjc^SOOmi CATIACTX-660 S3.50 eaVDeOIOmn CATI OCTX-SJIO SI 50 12 Vd- ? 500 ma ClTt DCTX.U5 S4 M 12Vtic5 AMP POWER SUPPLV ACDC Electronics * 12N5or squiv. trrpui: 100-240 Vac ^1^5^^ (wirsd tOf 1 1 5 Vac) 1 ' jv' Output: 12 Vdo \Sjfs., @ 5 amps. X^^^i Opan trams power supply. "^ 7- X 4 3/4" X y high. Regulatea>' CAT»PS-12S JST.SOeach NICKEL-CAD BATTERIES ;(RECHARGEABLE) AAA SIZE $1.50«ctl 1 2 volts 180 m All CATltNCB-AAA AA SIZE $2.00 each 1 2S voJts 500 rrAh CATiNCB-AA AA SIZE SZ.20 eacti WITH SOLDER TABS CAT«NCB.SAA C SIZE U.Z5 each 1,2 volts ISOOni All CAT# MCB-C OSIZE «4.eaeadi 1.2voltBl200mAli CAT# NCBD SiXENONTUBE;; P* — ^ 1' long llstliUjbt Mth 3 l/S" red and blecf( tvadt. Idftat for alac- Ironjc tlBxh or ttrob* prcjscls. CATi FLT.J 2 lof i1 OC BEUYS 6 VOLT D.C. - S.P.D.T. Arsmit ) nSD^V Supar smell relay. Rated: 1 tmp^ 30Vdc. TTt.direcntrivepoMi- t>le. OperatH on 4.^ to 14 Vdc. Coil: 220 ohma. 1 3/16- X 13/32" X7/ie-. CATiRSD-SV tlSOeecti ■10(srSi3.SO 12 VOLT O.C, D.P.D.T. DIP RELAY lAnialure relay Ills alandaid 1£ pin (dp] accliels or will diractiy mount to p.c. boards. Gt Ctarel LM44D00 ■ 2eO ohm ' 30 va SMtctiin^. CAT»CHLY-12 J2.30oacli 24 VOLT D.C, COIL 1 KuPayie 11 pirt base can be aocKatad. direct soldered or quicti connect tefmina^ can be used. 1 1S" 1; 1 MSrx ir. 3.P.D.T, • S amp contacis * 470 ohm CAT« RLY-SS24 S2.ZS each 0-6HOURA0TO SHUT-OFFTIMER Mli Fihodas, Inc. r.(ar1i-Tiina« 90007 Timor tits standard 3" deep walbox. Rated 20 amps@ 125 Vac. Turn knob to desired tirne. Includes hardware, beige waitplale, and knob. UL and CSA listed CATi TMC-S S5 75 each - 10 for $50.00 SPECIAL PURCHASE 210MFD330V PHOTOFUSH CAPACITOR Rubicon GE photolla^h capacitor. 0.79" dia , )t 1 . 1 " high. Thewi are new capacitors thai hava bean preppsd with 1.4" black and red wire laads sokJared to the terminals, CAT#PPC-210 $2 50 each 10CorS£2 5O ' lOOJorSEOOOO Lar^ qijantiEie? available Call for prking STEPPER MOTOR:; Ai^jaxP/NC82711-M1 17 Vdc dual coil. permanent magnet stepper. 23.25 ohm coil. 7.5 degrees per'^ftp. CAT#SMT-6 Se.OOeadi MOfortSO.OO INSTRUMENT ENCLOSURES Higti quality molded ABS instrument anckjsures Integrated PCPoard standolfs ancf two sets at vertical moLrnting slots lor troni and rear SLrb panels. Alt enckisures are 6" wide X 6 1«" do^. Choice ot three hts. Includes non-slud rul?Per teat and harc^^are. Available in beige, ivory, black, and blue. PMH hL CJLlM 2 1/4" CAT(UB-A S7«>eac«l lOlat&SDO 2:^" CATnrlMS-B S7.7S eac^ 10 In (67 » 3- CATtlilS.C tSCOudi lOlatTDOl Please specjty color RG-11^ 75 OHM VIDEO CABLE icon nSOOtt rolls of RG11/Ularminalad ID heavy duly F conneclora Includes 7S ohm terminator ^^j BndF-61 spHce^ono/teend. Now cab^s manufactured for IBM FC nal, works. IBM P/N 15O190S COWSCOPE. CAT»n<3-11-1 10OIL roll SI 5.00 CATi Ra-11-2 200 N roll S27 50 □r: LED'S STANDARD JUMBO OlFf^USeO T 1-J/4nu(5mm) ft RED CATllLED-1 IOtorSI.50 -tOOtwSIJ.OC CREEM CATf LEt>-3 lOtoriSOO' lOObrSIT.OO YELLOW CAT«LE[>-3 10 tor $2.00 , ICO tor (17.00 FLASHING LEO wSi tuiEl in Beflimg circoil B vgll operation. T1-^4 tSmm) RED St .00 aa<^ CATfLHM 10 for « 50 f\ GREEN SI .00 eich ■ CATI LED-4C 1 kv t9 &0 ff reiLow si.we.tJi H CAT*LEI}-4y to for $9 50 LED HOLDER tl TiMU pi*CM holder. ' ZH (3 CAT«HLED lOtetSH PHOTO RESISTOR ^OOohrnsbfighlttahl. fl^ 16X ohmi d»ik U 0182" (is K M'li^h.OH'tonj leads CATf PRE-7 ZbrSlOO 100 'c^ 5^5 00 ■ 1000 'or S<00 00 OPTO SENSOR 3r4ndf/d U'tliiped sJottid dplicd AvHldl with H&' gap b*twHn «id*t. 0.7y rnounBiig center* . CATfOSU-T 2roi-t1.00 REFLECTIVE OPTO SENSORS Thpf« uni ti h Kve VI tR em! tter and seruor pair pointng in Ihe Kajn*dr0<9li«l. Light from vmillar bouncat atfobjact to b* delecLvd by »en«y. EFtediv* range approx. 0.T5'. Three lypat avftiltble: TRW/ Opiroo M OP.B5^47-£ RedfljiguWr wf 26r wire leedt CATiOSH-4 2 for «t ,00 ^7(^31 TRW/Opron • OPa703A wiei PC pini. CATIOSR-J 75ard. alt the parts and instnjcttons to malte a simpte Hasher cirojit. A quick and easy project ^or any^ one with basic soldering skilfs. CAT^LEDKIT SI 75porJiit LED CHASER KIT agiicJtthis variai^ite speed led chaser. 10 lads flash saquenti^ihy i\ whatever s^eed you sel them lor, Easy to build kit includes pc board, parts arvf inatructiona. Ideal for special lighting elfects, costumes, etc. Operates an 3 to 9 volts. PC board isS" X 2.25". Agreal orw hour proJQct CAT# AEC $6 SO each STEPPING MOTOR:: CONTROLLER KIT; Learn <^ut {Stepping rnotors whitq building this simple circuit. Jndudes circuit board, motor and all pans except 1 2 Vdc power suppiy. CAT#SMKIT 5 1 9, 00 each ELECTROLUMINESCENT: STRIP(OLOW STRIP) AND INVERTER : ^ Ufled for tucklighting control paneta or as decorative or enier^ency priRne tghiirig icu rca. Tliin , loug hand flaxi bla, they opar' ate or^ tow o^rrent AC voltage The pre- tarred power source is a miniature DC to AC inverter TSasa haw a bit of an odd ih&pe. The stei'pa are 2.1 S" wide X S.Bir long and are 0.0^5' thick. The kumimiceni area le S.3r tong X 1 7^ wide and has on* corr>*r cut oti. leaving a uae^l area ot fairly good proportioni. We «r* aeling Ihe vt^ps and in- verters ae a package. Invertar operates on & Vdc Q tow strip, i nverier e nd hook-up diagram CATi GS SOO SS DO per eel EXTRA INVERTERS tjiput: e Vdc Outpvt; 225 Vac CAT«INV-t S2 00 each ORDER TOLL FREE 1-800-826-5432 FAX (818) 781-2653 • INFORMATION (818) 904-0524 Call Or Write For Our Free 60 Page Catalog Outside the U.S.A. send $2.00 postage for a catalog. Minimum Order $10.00 • All Orders Can Be Charged To Visa, Mastercard Or Discovercard • California, Add Sales Tax • Shipping And Handling $3.50 For the 48 Continental United States - All Others Including Alaska, Hawaii, P.R. And Canada Must Pay Full Shipping • Quantities Limited • No C.O.D. • Prices Subject to change without notice. M MAIL ORDERS TO: ALL ELECTRONICS CORP • P.O. BOX 567 • VAN NUYS, CA 91408 CIRCLE 107 ON FREE INFORMATION CARD 103 J AMECO ^^ ELECTRONIC COMPONENTS COMPUTER PRODUCTS 24 Hour Order Hotline (415) 592-8097 QUALITY PRODUCTS • COMPETITIVE PRICING • PROMPT DELIVERY Intel Math Coprocessors 8088 or 8086 Systems 8087 bWlHz $89.95 8087-2 8MH2 $129.95 8087-1 10MHz $169.95 80286 Systerns 80287 6MHz $139.95 80287-8 8MHz $209.95 80287-10 10MHz $239.95 80386 Systems 80387-1 5 1 6MHz S349.95 80337-20 20MHz $399.95 80367-25 25MHz $499.95 80387-33 33MHz $849.95 Memory Modules SIPPs 4125SA9A-8I! Mns, 256Kj(9 S32.95 41255A9A-10 lOOtis, 2S6K]i9 $29.95 4210O0A9A-7O 7[ms. I MegiS S104.96 42imA9A-aO SOn$. iMegx9 $39.95 42'tO<]aA9A-1Il iDOns. 1Me9x9 $39.95 940ML-80 80rvs. (Weans $449.95 SIMMs 41256A98-80 BOns, 25$Ki9 $32.95 4125eA9B-1l} 100ns. 25EKI9 $29.95 421[|[I0A8B'10 100ns. IMe^xS S79.95 421tl01)A9B-70 /(Ms. 1 Megj9 $109.95 42iraA9B.S[i 80rs. iMegnS $99.96 421000A9B-10 100ji$. 1 UegiS $S9.95 94mS-6D OOrvs.dMegxg $449.95 NEC V20 & V30 Chips UPDT0108-5 SMHtVSaChip S5.25 UPD7CI108-e 9MH2. VSOChip $6.95 UPD7D1OS-10 10MH2,V20Chip $10.95 UPD70116-B eMHi.wochip $7.95 UPD701 16-10 lOMHl.VSDOlip $12.95 Dynamic RAMs TMS4416-12 120115. 16Kx4 $2.49 TMS4416-15 150ns. 16Kl(4 (2,25 4116-12 120ns. 16Kx1 $1.49 4116-15 150ns, IOKki $1.19 4116-20 200n5. 16Kx1 $.99 4164-100 I Mrs, frlKjl S2.2S 4164-120 120flS, 64KX1 $2.09 4164-160 15Clrs, 64I&1 $1.95 4164-200 SOOns, WKkI (1.75 41256-60 60ns, J56KI1 $4,95 41256-80 BOns, 256KS1 $3.75 41256-100 100ns. sseKxi $3.15 41256-120 120ns, J56Kx1 $2.95 41256-150 15flns.256Kjil $2.59 41464-80 80I1S, eJKri 53.95 41464-10 lOOns. 64Ki4 S3.25 41464-12 120ns. 64K»4 $2,95 41464-15 160ns. 64Kl(4 $2.49 511000P-70 70ns, 1 Megil $10.49 511000P-6D sons, 1 Me^xl $9.95 SIIOflOP-IQ lOCns, 1 Megtl $0.95 514256P-60 80ns, 256Kx4 S10.49 C/5 514256P-10 100(15, 256Ki4 SI 0.25 o o (T Static RAMs H O III 6116P-3 tSOns, 16K (CMOS) $2.59 6264LP-10 100ns, 64 K (CMOS) $6.49 _l LU 6 6264LP-15 150ns, 64K (CMOS) $4.95 43256- 10L 100ns, 25SK $3.95 43256-1 5L 150ns. 256K $3.49 < 52256LP-15 1 50ns. 256K (CMOS S9.49 [T ^artial Listing PROTOTYPING PRODUCTS Jameco Solderless Breadboards Pan No. JEZ1 JE23 JE24 J £25 JE26 JE27 Dim. L"xvr 3 26 K 2,125 6.5 X 2.125 6.5! 3,125 6.5 1 4,26 6.87615,75 7.25 > 7.5 Contact Binding Points Posls Price 400 B30 1,360 1,660 a, 390 3,220 $4.95 $6.95 $12.95 $17,95 $22.95 $32.95 Oscilloscope Probes ■ Attenuation: xl/xlO J ■ Capiacltance: ^■£r"''W'' . 180pF/22pF • Sandwidihr 3HHi'40MHz ■ Length; 60' LF1 80 40MH7 Oscilloscope Probe $19.95 GoldStar 20MHz Oscilloscope • Large 6" r&clangular display - High $ensitiviiy: 1 mV/dlv GS7I120 Osciliosmpe $499.35 Metex Digital Multimeters General Specs; - Handlleld, high accuracy ■ AC/DC voltage, AC.,'OC ctJfrenl, resislanca. diodes, continuity, Iransistor liFE » Manual ranging wf overlcad proteclion M3650 « M466D only: < Also measure trequoncy and capacitani^e M4650 only: < Data hold switch - 4.5 digit M3610 35 Oisil MiiHimelef , $59.95 M3650 3.BDiCKlMullHiie]srw/1^r«tUBncy& Capacitance $74.95 hM650 4.5 Digil ^'Frequency, Capacitanca and □ala HoU Swxcn $99.95 Multimeter Specials MSO: . AC^DC voilage, AC^DC current, resistance. diodes, conlinuity & Irequertcy - Full auto- ranging on DC voltage ♦ HigWiow semi- autoranging tor AC/DC current and ohms ■ Data liold switch - Extra, larga disptay M8Q 3.75DigltMulMtler $59.95 MSSOO: - AGvDC voltaga, AC/OC current, resistance, diodes, continuity, dwell angle and engine RPM ' High surge voltage protection M39Q0 3.5 DIgil Uulhmeter $59.95 Prototype Design Stations Features: ■ Removable soideriess breadboard • Variable and fixed DC power supply • Multi- frequency signal generator ■ Analog nnultimeler ■ 8 bicolor LEOs (red & greenj ■ 8 logic switches ■ Logic probe ■ Ligfited power switch • Fuse overload protected • Pulse Generator • Binary coded decimal (BCD) to 7-segmen1 decoder/driver ■ DB25 connector • Frequency counter (IHz to 1 MHz) ' Sturdy ruggedized case WM2 .$299.95 Soldering and Desoldering Stations 60 Vtfatt Analog Display Soiderirtg Station ' Electronic temperature control frorn 200' to 9?S=F ■ Cartridge heating element for a longer life ol the soldering tip XY1683 $69.95 60 V^atl Analog Display Soldering SeaEion * Electronic temperature control Irom 200'' to 37S'"F ■ Ceramic tiealing element tor a steady temperature and long lite XY 2660 $8 9.95 60 Watt Digital Display Soldering Station - Electronic temperature control frcm 200" to eZB^F ' Temperature displayed on easy to read .560"H S.digit LED readout » Nichrcrr^e heating element XY960 $109.95 30 Watt Electronic Temperature Controlled Desoldenng Station ' Electronic temperature control trom 212- to 842'-F * Self-contained high rotary vacuum pump XY999 $299.95 A.R.T. EPROM Programmer UVP EPROM Eraser f;--^ ' Programs all current EPROMs in the 2716 to 27512 range plus the X2864 EEPROM • RS232 port ■ Software included • Erases all EPROM's • Erases 1 chip In 15 minutes and 8 chips in 21 min, • UV inten- sity: 6800 UW/CM^ EPP. .$199.95 DE4 $79.95 Jameco Universal tC Programmer Memory Devices: EPROMS, EEPROMS and PROMS Logic Devices: PALs, GALs, RALs, EPLDs, EEPLDs and FPLDs ■ Stand alone or computer controlled mode via RS232C port • The jesso uses the JEDEC standard tor logic devices. Accepts input (rom virtually all major software packages including: PALASIul, PLAN, CPU L. ABEL, and AMAZE JE680 $1799.95 104 Over 4000 Components and Accessories in StocitI CIRCLE 114 ON FREE INFORMATION CARD Call for Quantity Discounts J AMECO ^^ ELECTRONIC COMPONENTS COMPUTER PRODUCTS Request Jameco's 1991 Catalog for a Complete Listing of Components, Test/Measurement Equipment and Computer Products Jameco 16MHz 80386SX Desktop Computer Kit Assemble Your own Computer Kit! '" '"*~ Building your own computer provides you with a batter understanding ot components and their (unctions In-deptti assembly instructions inciuded iHave your new computer assembled and running In three flours, using common tools Software included '' Purctiase computer kits configured by Jameco or design your own Jameco 16MHz 80386SX Desl(top Computer Kit icludes: 80386SX Motfierboard with 2MB RAM (expandable to 8ti/IB) 101 -key enhanced keyboard Multi I/O Card Toslliba 1 .44MB, 3.5" DSHD floppy disk drive Baby sized desktop case 200 Walt power supply DR DOS by Digital Research and Diagsott's QAPIus diagnostic software $1199.95 JE3816 ""■"'">'""» lameco IBM 'C/XT/AT Compatible Cards JE1077 JE1 043 360KB/720KB/1 .2r^Bf1 .441/B Floppy Disk Contralter Card (PC«T/AT) .. $49.95 JE1050 Monochrome Graphics Card w/Parallel Printer Porl (PC/XT/ AT) $49.95 JE1052 Color Graphics Card w/ Parallel Primer Pol (PC/XT/AT) $59.95 JE1055 EGA Card w/ asSKS Video RAM (PC/XT/AT) $149.95 J El 060 I/O Cardw/ Serial. Game. Printer Pon & Real Time Clodf (PC/XTJ ...$59.95 JE1062 RS232 Serial Halt Card (PC/XT/AT) $29.95 JE1065 1/0 Cardw/ Serial. Game ard Parallel Printer Port (AT) $59.95 JE1077 Multi I/O Carel w/ 360K8/72QKB/1 .ZMBn .44MB Floppy Conlroller (AT) .. $99.95 Jameco 32-Keypad Fujitsu 101 -Key Enhanced Keyboard i'l I'tl f MTDVUn zJmm IBM PC.XT/AT/386 Compatible 12 turrclion keys Separate cursor and numeric keys IBM PC/XT/AT/aae CompaliWa 12 lurction keys Unit Mjmescompleie wiih software on 3-5' disk and user manual FKB4700 $79.95 JE2018 $59.95 Jameco Digitizer Tablet * AutoCAD 10 template and four, button puck • Resolution: up to 101S lines per inch ■ Accuracy: = 025" • Emulates three ot the worlds most popular formats: Summagraphics MM. Summa- graphics Bil Pad One. Calcomp 2t)00 • EEPROM allows custom configuration J CAD Digitizer Tatitst $269.95 Stylus Tw(]B(i«EHiSty1iis....$39.95 DFI Handy Scanner • IBM PC/XT/AT Compatible • 4" Scanning Window ■ 400 dpi ^ HS3000P $219.95 Logitech Mice USER MBUS serial MCMjse A MouseWafe Solware $89.95 MtKise Vf.'Sus Board £ Mou^- Ware Soltware $99.95 Modems Externa) Modems 120QC DaiaHimixi sen Bams $59.85 24aOMjini«3?Biui $1 49.95 Internal Modems 1200B jawniSDDBius S59.95 2400B Jmeazax^u! ., $99.95 Modems lEseeJ above induds ftoCwntn sotr^rarfl IBM Compatfbte Cases and Power Supply ItllMIMUl jeioio JElDtO Hc^Tq!SBnlHI>CXTCl» $39.9S JEia36 :i»i«BB»)tTPoMiS:f^ S93.S5 JE2()32 Un-Vnaicmm^mi^nifii S\^M JE2030 v«aiCiiie»3rowp« Sum S319.9S Floppy Disk Drives Tosftiba 356K U 3 5" 1 JiMB Ipitetnal Dnue . . . S1 1 9.9S Teac FD55B 515- MOKB MbBftM] Dnus ... $89.95 FD5SG 6 2S- 1 2MB Internal Dnve.... $99.95 Hard Drives & Tape Back-Up XT Hard Drives also available Conner (16-bit IDE) CP304'l F 4CJMB (25ms) J.S'Low Prtjlile.$469.95 CP31 &4F 80MB |!5ms) 3 5-HH $699.95 CP31l}4F100MB(S5ms|3,6'HH $799.95 MIcropoMs (ESDI) t654-7 150MB (lerns) 5.25*tlH.... $11 99.95 1558-15 300Me(18ms)5.2S'-FH $1799.95 Colorado Memory Systems ■ IBM PCXT/AT/SSS Compatible ■ Back-up 40MB m 40 minutes ■ Backup 60 !o 120MB with extended Eape^ and data compression software J 1 tame rape sacKup $349.95 KE10 Esicmal Enclosure M S149.95 TB40 40MB Tape CarlntlBe J24.95 TS6Q EDMS Tapa Canriuge $29.95 J AMECO ^^ ELECTFIONIC COIWIPONEPTTS COMPUTER PRODUCTS 1355 Shoreway Road. Belmont, CA 94002 24 Hour Order Hotline (415)592-8097 SSO.DD Mfnimum Order FAX'S (415) 592-2503 or (415) 595-2664 TelSJf 176043 - Ans. Back. Jameco BIml Daia Sheets - 50c each For a FREE 43-Page Ftter send $2.00 to cover Ftral Class Postage and Kandling ^ 1990 Jameco Electronics 11. '90 CA Residents Add 6-25%. 675% or 7.25% Sales Tax Shipping - Add 5% plus Si -50 Insurance l.May va^y acco^dlngi to wsiQll and dipping memcd) Terms: Prices subject to change without noNce. Stems subfect to availability and prior $alo. ComplBta' M o1 tsf m^wajTranlias is available upon r&que^l 2 § m m m Ji t»^ RSOs (Reol-Time & Storage Oscilloscopes) From HITACHI The RSO - its the new solution View, Acquire, Test, Transfer and Document Your Wovefojm Data "^^k 4-Chonfiel, lOOMS/s Model Introductory Price 1 00 M&s {2SMS/S or 4 channels simultaneously), lOOWHz, 4kwi ich., 2l!w>;2ch., 1ln»i4cn. VC-6145 (4,695,00 Compact, full Feature Models WM&s, lOOMHz, 4kw X icn., 2kw X 2ch. VC-604S J 3,049.00 20MS(S. 50MHI, 2hw J( 2cH VC-6025 $ 2,295,00 Low Cost/High Value Models 20MSj's. 50MHI, 2kw t 2ch. VC-6024 $ 2,049.00 20W&S, 20MHz, 2kw x 2ch, VC-60;3 $ 1 ,749.00 RSO$ ^rom Hrtachr feature such functions as roll mods, avaraging, savs memory, smoothing, interpolation, pratriggering, cursor moasufsmants, plotler interface, and RS-232C Interface. With theconrfort of analog and the power o1 digital. Hitachi Portable Scopes DC to 50MHz. 2-Channet, DC offset function, Alternate magnifier function V-5Z5CHTReadoiJt,CursorMBas. $1,026 V-523 Delayed Sweep _ _ |pg$ V'S22 Basb Modal $69S V-212 $435 DCtoSOMHi Dual Channel V-422 40MHz Dual Trace t79S 20MHz Elenco Osc illoscope $375 MO- 1251 Compact Series Scopes Delayad SwHp Lightweight (13lbs) 2mV Sens 3 Yf Warranty Modal V-106S Srtown This series provides many new functions such as CRT Readout, Cursor measurements (V-1085/1065/e65), Frequency Ctr (V-1(185}, Sweeptime Auto ranging and Trigger Lock using a 6-tncli CRT. You don't leel the compadness in terms of performance and operation. V-660 60MHz Dual Trace *1,195 V-665 60M Hz Dual Trace w/Cursor *1 ,345 V-1060 100MHz Dual Trace $1,425 V-1 065 100MHz Dual Trace w/Cursor $1 ,695 V-1085 100MHz Quad Trace w/Cursof $2,045 V-1100A 100MHz Quad Trace w/Cursor $2,295 V-1 150 ISOMHz Quad Trace w/Cursor $2,775 • Dual Tracft • Ccrnpomnl Tfiisler - e^ CRT « X-Y Operatbn • TV Sync • 2 p-1 Probfts FREE DMM witht purctiase of ANY SCOPE SCOPE PROBES P-165MHZ, Ix, lOx S19.95 P-2 lOOMHz, Ix, lOx S23.95 Elertco 35MHz Dual Trace ^m^c Good to 50MHz ?4a5 MO- 1252 • Higfi luminancs 6" CRT • ImV Sensitivity • €KV AcceleraiEon Voltage • lOrs Rise Time • X'Y OparatJQfi « Z Axis -.-___ . _ l-'WyT • Delays*! Triggering Sureep •I?*1L?, rl^.'VjJj' • Includes 2 P-1 Probes All scopes Include probes, schematics, operators manual, and 3 year (2 yrs for Elenco scopes) world wide warranty on parts & labor. Many accessories available tor all Hitachi scopes. Call or write for complete specifications on these and many other fine oscilloscopes. WE NOW CARRY COMPLETE LINE OF FLUKE MULTIMETERS Models 21F 63 23F 85 2SF 87 27F 80SOA 73 8060A 75 77F 8062A + More CALL FOR SPECIAL PRICING True RMS 4 1/2 Digit MulHmelef M-7000 $135 .ai% DC Accuracy .1% Resistance with Freq. Counter and deluxe case Function Generator Blox #9600 t?*# $28.95 Provides sine, triangle, square wavefmm \Hito IMHz AM orFM capability 10 Function Multimeter ' - ,' CM-365 ] $65 •--'.:■■' AC + DC Voltaige i Amps ®"® h Resistance to 2IXI0M a , 7? ;T ; *' Diode. Logic, i Trans test ^^^^H Capacitance to 2(X)iiF Digital Capacitonce Meter ;^f.. CM -1550 $58.95 9 Ranges .1pl-20,0t»u!d .5% t>asic accy Zero control with case Triple Power Supply XP-620 Assembled $G5 Kit $45 ZtotSVattA. ■2 to -16V at 1A (or 4 to 30V all A) and 5V at 3A Contains all the desired leatures for doing experiments. Features shol circuit protection, all supplies. •v; Digital LCR Meter LC-1801 $125 Measures; Coils 1uH-2(X)H ^^ Caps .1pf-20Oul f^i^f Res .01-20(4 Wide Band Signal Generators SG-9000 Mi^.''^'' $129 RFFteqIOOMMMHl AMMcdiilatiwioMKHz Variable RF output SG-950aw Digital Display and tSOMHz built-in Counter tZ49 f-ji, A^ Current Meter f ^V ST-1010 JH $69.95 1 lOOQAmps [ Data t Peak hold B Functions Deluxe Case Decode Blox ..■^.■_-.^-. I #9610 or '^^ I $18.95 Quad Power Supply XP-580 $59.95 UTTTZ »610 Resistor Blot 47 ohm to IMS tOCKpol t9620 Capacitor Bloi 4?pf to lOMFO Fully regulated anH" short circuit protected XP-S75 without meters S39.95 LEARN TO BUILD AND PROGRAM COMPUTERS WITH THIS KIT! INCLliDESi Alt Parti, Au«mbty and L«uon Manual Model MM-eooo $129.00 Digital Triple Power Supply XP-765 $249 0-2t)VanA 0-20Vat1A 5V at 5A FuEy regulated. Short circuit protected with 2 tintit control. S separate supplies XP-WO wim AnalOfl Meters jiTS OF-8016 Function Generator witti Freq. Counter $249 Sine, Square. Triangle Pulse, Ramp. 2to2HHz Freq Counter .1 - 10MHz ^^m aF-goi5 without Freq. Meter $179 Startng (rom scratt^h fov tnuikj a compiole tysiem, CXjf Mtcra-Masiof tfainert&ac^iesyou lowritD mia RAMs, ROMs and run 36095 microproc^- sof. which uses similar mitchine lar^uage as IBM PC Vou will wnie iha it^tial irrstruc&Qm Lo IbII itH aOBS pTDcASsOf ko^l scan&d artd store tf>ee« insinJCtiorB in permanent memQiy in a 281& ^ PFIOM. Teaches you all about inpLjit and oLitpuL ports, cDfnpubr bmflrs. Build your Own kayboard and taam how ta scan ka/tx>ard and dciplay. No previous computer knowledge re<;uired, Strnpls easy (o undiar^iand instniction tsadies ycm to write in machine language, ROBOTICS KIT FOfi ABOVE (MM-eOlO) $7},95 WE WILL NOT BE UNDERSOLD! C & S SALES INC ""^ "^^ ^°"^^ ^^^^ Guarantee UPS Shipping: 48 States 5% c=p^ 1245 Rosewood, Deerfield, IL 60015 2 Year Warranty Prces s.t,.ec> ,0 ch..., ($10 Max) IL Res., 7% Tax ^^^^ (8OO) 292-77 U (708) 541-0710 WRITE FOR FREE CATALOG CIRCLE 109 ON FREE INFORMATION CARD On the line, on the bench, or on the road. 'Qie low- cost solution is Tek. Do you debug the design? Veriiy the production ain? Service the fiiushed product? Then for low-cost solutions built for your application. there's only one place to go. Tele's 2200 Series oscilloscope family. There are ten scopes in the 2200 Series, from 20 to 100 MHz and $695 to $5495. And three of them demon- strate fiinctional power at its best: the 100 MHz 2232, 50 MHz 2211, and 100 MHz 2245A If you can't afford to miss a thing, get the 2232 digital storage oscilloscope. With 100 MS/s sampling, ten nanosecond glitch capture, waveform cursors, a 4K record length and 3OK of battery-backed memory, it makes routine work of problems otlier scopes can't even see. For the best performance value in digital storage, try the Tek 2211. It offers a standard hardcopy interface, measurement cursors, 20 MS/s sampling and a 4K record length per channel, plus digital/analog ope- ration — all for only $2695. And for the ultimate in low-cost troubleshooting: the $1995 2245A. It's a 100 MHz real-time scope with auto setup, cursors, four independent channels, dual time bases and more. So if you want the best low-cost solution on the line, on the bench, or on the road with you, just get on the phone. And call your local Tek representative today. IfSOflUS. Purchase a 2232, 2211, or 2245A by October 15, 1990 and you can receive a $345 digital multimeter free!* The CDM250 measures cunent, voltage and resistance, has overioad protection and is UL certified. To get yours, contact your local representative or distributor and place your order with Option 4X. Or call Tek direct at: 1-800-426-2200 Ext. 225 Qe Ibktronix COMMITTED TO EXCEL±£NCE CIRCLE 92 ON FREE INFORMATION CARD 'Offer valid in U.S. only. You mu^t ask for Option 4X and ciaie purchase order between July 15 and Octoter 15. 1990 to qualify. © 1990 Tektronix Inc . BOB- 1 01