48783 SCREEN YOUR TELEPHONE CALLS ELECTRONICAL 777 ECHNOLOGY - VIDEO - STEREO - COMPUTERS - SERVICE DIGITAL CIRCUIT SIMULATION USING SUSIE Are breadboards becoming a thing of the past? lll 71896%S783 M! 1 1 2 BUILD THIS BENCHTOP FREQUENCY COUNTER PEBB59 ft'OV Wp It's inexpensive, and easy to build, yet gives performance over 1GHz BUILD THIS HI-TECH CHRISTMAS CARD Frequency-selectJve filters help create a spectacular display CHOOSING THE RIGHT TEST PROBE The right probe can really make a difference • ' • T-i : * i i * S2.95 U.S. $3.75 CAN A GERNSBACK "inSw^fcfij 1 I3I!T!1T3B8*!?B m ■■ FLUKE AND PHILIPS FLUKE FLUKE 73 FLUKE 75 FLUKE 77 S79" ■"•■' flSfl" Anaioa/Qgiiai display Analogrt)£itaJ djspty A/«logrt>igrtai dc^lay Vols nnmi. 10A VOJS ofuns. K»S Vote. ohms, IDA & liusBfi dude ica mA (Mm lujaj], ni , tci, lustd), ifSi'h,**- own* On*"* accuracy 1000+hour omusxdc vane) 3* mac dc. •ccuracy briny fe 3 year *arrariy \uoAtecomi.iuif Autoningefrjnge hold 2000+ l»ii oamvy Wo ;; ,>:<'*,v'.r:. Touc)>i«kI* Audfcle cOnUrtuily Aolorangft'fange hold J 2000 + hoof « Multa/pose holster j 3 year wjrranly il "Suggested u S. 1st ones THE GLOBAL ALLIANCE IN TEST & MEASUREMENT - 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 the 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 resistance 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. Made in the USA using state-of-the-art man- ufacturing methods, every Fluke 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-FLUKE, ext 33, for a free brochure. Jotin Flutt Mlo Co.. Inc. P.O. Bo* 9O90. Ewerell, WA 98206. U.S.: (206) 356-5400 Canada: H15] 8SO-7WO Other countries (236) 356-5500. 6 1990 John Flute Mlrj. Co., Inc. All nflhts reserved Ad no. 0701-F70 FROM THE WORLD LEADER IN DIGITAL MULTIMETERS. FLUK CIRCLE 121 ON FREE INFORMATION CARD December 1990 ei,„ ijrJjcntcs Vol. 61 No. 12 33 BENCHTOP FREQUENCY COUNTER Build an inexpensive, full-function frequency counter. Carl Bergquist 40 THE CHRISTMAS CARD Our electronic Christmas tree makes a bright holiday greeting! Ron Holzwarth 48 TELEPHONE CALL SCREENER Put an end to junk calls. John G. Keller 1 mJiSfmmmm 1 ■ 1 PAGE 57 63 CHOOSING THE RIGHT TEST PROBE It's important to know which probe meets your testing needs. Bill Hansen EHMSM 57 SUSIE Simplify digital design using SUSIE, the Standard Universal Simulator for Improved Engineering. TJ Byers 86 COMPUTER CONNECTION An electronics-lab simulation program. Jeff Holtzman PAGE 63 EEMSME 6 VIDEO NEWS What's new in this fast- changing field. David Lachenbruch 24 EQUIPMENT REPORTS Radio Shack's Micronta Voice Meter. 69 HARDWARE HACKER Santa Claus machine update, and more! Don Lancaster 76 AUDIO UPDATE The amplifier- transfer-function controversy. Larry Klein 78 DRAWING BOARD Keeping the DTMF-generator circuitsimple. Robert Grossblatt 81 IC SPOTLIGHT What's new in IC and systems development. Mike Mullin 100 Advertising and Sales Offices 100 Advertising Index 8 Ask RE 49 Free Information Card 16 Letters 91 Market Center 30 New Lit 26 New Products 4 What's News a o m rn 3D 5 CO CJ z O rr i- o LU -I UJ o < JML -icfctn. ywa HUMM cam tuctwwtitir mr~MHitilni Mziectmcics •vuiiMJiiiLNriitor' <•* j*» . ;» ' n»T Pdaar OMIt 1MA1 CAM Tis the season. . .when we all wrack our brains to come up with unique gift ideas. This year, we've made it easy, with a project that's right in the spirit of the holiday sea- son. Our Electronic Christmas Tree is really a PC board whose traces form the branches. Multi-colored LED's look like Christmas-tree lights, and blink in time with any kind of audio. Turn to page 40 to see our festive project that makes a great holiday greeting or window display. And if your wallet's feeling the pinch of holiday shopping, you'll appreciate our Benchtop Frequency Counter. Half the price of commer- cial models, it offers an impressive array of functions. The versatile, easy-to-use instrument is based on the Intersil ICM7216C. To find out more, turn .to page 33. rrwr * E25EEE THE JANUARY ISSUE GOES ON SALE DECEMBER 4. BUILD A MACINTOSH Use an Apple motherboard to build your own Macintosh computer — for a fraction of what Apple charges. R-E's E-Z SHORTWAVE RADIO Build it, then modify it to receive any frequency that you're interested in! NEGATIVE-ION GENERATOR Experiment with high-voltage electronics and the effects of negative ions. BATTERIES A review of rechargeable-battery technology. 1990 ANNUAL INDEX A complete listing of our feature articles and departments. As a service to readers, RADIO-ELECTRONICS publishes available plans or information relating to newsworthy products. techniques and scientific: and technological developments. Because of possible variances in the 'quality and condition of materials and workmanship used by readers. RADIO-ELECTRONICS disclaims any responsibility for the safe and proper functioning of reader-built projects based upon or from plans or information published in this magazine. Since some of the equipment and circuitry described in RADIO-ELECTRONICS may relate to or be covered by U.S. patents, RADIO-ELECTRONICS disclaims any liability for the infringement of such patents 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 0033-7B6B December 1990. Published monthly by Gemsbaek Publications, Inc.. 500-B Bi- County Boulevard. Farmingdale, NY 11735 Second-Class Postage paid at Farmingdale, NY and additional mailing uffaces. Second-Class mail registration No. 9242 authorized at Toronto. Canada. One-year subscription rata U.S.A. and possessions St 7.97. Canada S23.97, all other countries 626.97. All subscription orders payable in U.5A funds only, via international postal money order or check drawn on a U.S.A. bank. Single copies S2.95 1990 by Gemsbaek Publications. Inc. All rights reserved. Printed in U.S.A. POSTMASTER: Please send address changes to RADIO-ELECTRONICS, Subscription Dept.. Bcw 55115, Boulder, CO 80321-5115. A stamped self-addressed envelope must accompany all submitted manuscripts and/or artwork or photographs if their return is desired 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 otherwise. Electronics Hugo Gemsba c k (1 884- 1 967) founder M. Harvey Gemsbaek. editor-in-chief, emeritus Larry Stockier, EHF, GET. editor-in-chief and publisher EDITORIAL DEPARTMENT BHan C Fentort. editor Marc Sptwak, associate editor Daniel Goodman, technical editor Kim Dunleavy, assistant technical editor Terl Scadutct, assistant editor Jeffrey K. Holtiman computer editor Robert Grossblatt. circuits editor Larry Klein, audio editor David Lachenbruch contributing editor Don Lancaster contributing editor Richard D. Fitch contributing editor Kathy Terenzl, editorial assistant ART DEPARTMENT Andre Duzant. art director Injae Lee, illustrator Russell C. Tru olson, illustrator PRODUCTION DEPARTMENT Ruby M. Yee, production director Janice Box, editorial production Karen S. Tucker advertising production Marceila Amoroso producti on ass ista nt CIRCULATION DEPARTMENT Jacqueline P. Cheese boro circulation director Wendy Alanko c ircu latio n ana lyst Theresa Lombard o 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 Liter- ature, Microfilm & Microfiche editions are available. Contact circulation depart- ment for details. Advertising Sales Offices listed on page 100. a/"% The JUV Aud.l ' \ W Bureau ol Circulation COAX ADAPTER KIT ■ Create any adapter in seconds ■ Make al! combinations of BNC, TNC, SMA, N, UHF, Mini-UHF, F and RCA. The TP1 3000A kit contains male and female connectors of all 8 types, and 6 universal inter- faces. Simply screw any combination of 24 connectors to one of tbe interfaces to create the desired adapter, $130 TEST PROBES, INC. 91 78 Brown Deer Road. San Diego. CA 92121. Call toll-free forcatalog: 1-800-368-5719 CIRCLE 225 ON FREE INFORMATION CARD ECONOMICAL SILICONE RUBBER TEST LEADS Best value in moderately priced leads. High quality, soft, silicone rubber cable. Banana plug on measuring tip accepts push-on accessories; alligator clips included. Plugs have spring- loaded safety sleeves. Model TL1000 $14.00 Satisfaction guaranteed. TEST PROBES, INC. Call toll-free for cata- log: 1-800-368-5719 CIRCLE 226 ON FREE INFORMATION CARD FREE PROBE REFERENCE GUIDE One-page chart lists TPI probes for most oscil- loscopes. Also cross references other probes lo less expensive TPI equivalents. Performance and satisfaction guaranteed. TEST PROBES, INC. Call toll-free for guide and catalog. I-80O-368-5719 CIRCLE 227 ON FREE INFORMATION CARD DELUXE TEST LEAD KIT Users call TPI leads The Absolute Best. The TLS2000 features the highest quality cable in the industry - with spring-loaded safety-sleeved plugs. U.L listed (file E7958 1). Kit: $30 Leads and probes only: $19 Satisfaction guaranteed. TEST PROBES, INC. Call toll-free for cata- log: 1-800-368-5719 CIRCLE 228 ON FREE INFORMATION CARD The World's Most Popular Probe Model SP100 $A1 100 MHz Switchable Ix-IOx ...,*T,J CIRCLE 180 ON FREE INFORMATION CARD More SP100 Probes Have Been Sold Worldwide Than Any Other Probe Ever Made • For Tektronix, Hewlett Packard, Philips, Leader, B&K, Kikusui, Hitachi, Bccknian and other oscilloscopes • Immediate delivery from distributor stock • Economical - Substantial savings compared to OEM probes • Durable - Unique cable is slim, very flexible and resists breakage • 10 day return policy - Guaranteed performance and quality Free cross reference chart for all makes of scopes and probes. Call toll-free for chart and name of your local distribu- tor. PROBES, INC. TPI 9178 Brown Deer Road San Diego. CA 92121 Toll Free I-S0O-3fi8-571<> o m o 03 m 3J to to o CIRCLE 123 ON FREE INFORMATION CARD WHAT S NEWS A review of the latest happenings in electronics. The "new" NESDA The entire by-laws of the National Electronics Sales & Service Dealers Association CNESDA) were replaced with new ones at membership voting sessions held last August at the an- nual National Professional Elec- tronics Convention (NPEC) in Las Vegas, NV. Although the rules were completely rewritten, the actual changes in NESDA operations are few t _and mainly involve shifting con- trol from the state to the national level. The new laws allow NESDA to control its own destiny as a national association instead of being con- trolled by state organizations. Under the new rules, NESDA will control the billing of all members, but will encour- age 'Associate" ventures with re- gional, state, and local organizations. Local billing will still be permitted un- der certain conditions. Other changes that were made included re- placing the NESDA House of Repre- sentatives and Regional Vice Presi- dents with a Board of Directors. Elections for several positions were held at the convention, which was attended by more than 600 peo- ple. Elected as president of NESDA was Cornelius C. ("Connie") Bell, re- tired owner of C.C, Beil Electronics in St. Louis, MO. Bill Warren, GET/ CSM, of Warren's Audio & Video Ser- vice of Knoxville. TN was elected vice president. The ten members of the Board of Directors were also chosen. Intense laser beam Researchers at Bellcore CMid- dletown Township, NJ) have dis- covered a way to focus 1 60 extremely small laser beams into a single, powerful beam. Separately, each sur- face-emitting laser is virtually invisible to the naked eye, measuring about one-tenth the diameter of a human hair, and does not generate enough power for useful applications. The en- ergy that can be harnessed from the experimental arrays, on the other hand, could be used on microchips in optical computers and neural net- works or possibly for creating holo- graphic images DR. ROBERT TINKER (LEFT), CHIEF SCIENCE OFFICER OF TECHNICAL Education Research Centers, a non-profit organization committed to improving science and mathe- matics education, was presented with the first Siemens Award for the Advancement of Science at the Computerworld Smithsonian awards event held at the National Building Museum in Washington, D.C. The innovative educator is credited with first introducing networked programs using computer technology into the science classroom. He has developed such influential programs as the National Geographic Kids Network, the Star Schools program, LabNet, and the Global Lab, which engages students, teachers, and scientists around the world in tackling ecological problems. According to Hans Decker (right), president of Siemens Corporation, "Dr. Tinker's vision of children as scientists, tackling real world problems, makes him the ideal recipient of this award." When the microscopic lasers are packed close together, they each re- ceive a uniform amount of electrical current and can "lase" in concert. Bellcore's array consists of surface- emitting lasers, which direct light up off the surface instead of horizontally, allowing many more lasers to be packed onto a single microchip. Ac- cording to Hoi Jun Yoo, the principal researcher, "Since you can place lasers anywhere on the surface of a chip, you can make the best of avail- able "chip real estate." The small lasers require about 10.000 times less space than semiconductor lasers used in similar limited applica- tions today. When etched onto a semiconduc- tor in a special array of 160 2-micron- diameter lasers spaced 0.2-microns apart (one micron equals a 40-mil- lionth of an inch), the vertical beams of light generated blend with one an- other through a phenomenon called "phase locking," whereby different optical fields overlap to create the equivalent of one light source. The result is the creation of one extremely narrow beam, analogous to several small streams feeding into a powerful river. The Bellcore experiment is the first time scientists have managed to suc- cessfully harness surface-emitting lasers to form a single laser light source. The research team is now working to integrate the prototype arrays with electronic devices that will be able to accurately control and steer the di- rection of the beam. R-E ELENCO & HITACHI PRODUCTS AT DISCOUNT PRICES «& RSOs (Real-Time & Storage Oscilloscopes) From HITACHI The RSO - its the new solution View, Acquire, Test, Transfer and Document Your Waveform Data %, %3fcC" ins wv * ii m uivr nerr ^ututiuii ■* PV* 1 0OMS/s (25MS/S on 4 channels simultaneously), 1 QOMHz. 4kw x i ch„ 2kw x 2cti. h 1 kw x 4ch, VC-61 45 3 4,695.00 Compact, Full Feature Models 4QMSW, 100MHz, ideas, practical projects and expert guidance. 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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, describ- ing all the current selections — mains, alternates, extras— plus bonus offers and special sales, with scores of titles to choose from. • Automatic Order. If you want the Main Selection, do nothing and it will be sent to you automatically. If you prefer another selection, or no book at all, simply indicate your choice on the reply form provided. You will have at least 10 days to decide. As a member, you agree to purchase at least 3 books within the next 2 years and may resign at any time there- after. • Ironclad No-Risk Guarantee. If not satisfied with your books, return them within 10 days without obligation! • Exceptional Quality. All books are quality publishers' editions especially selected by our Editorial Board. FREE when you join! Six Easy Home-Improvement Projects A treasury of do-it-yourself projects to add value and comfort to your home. Urn HOW-TO BOOK CLUB Blue Ridge Summit, PA 17294*0800 Please accept my membership in the HowTo Book Club and send the 5 volumes listed below, plus my FREE copy of 6 Easy Home-improvement Projects (343P), billing me S4.95. If not satis- Red. I may return the books within ten days without obligation and have my membership can- celled. I agree to purchase at least 3 books at regular Club prices during the next 2 years, and may resign any lime thereafter. A shipping/handling charge and sales lax will be added to all orders. Name Address City State _ Zip Phone Signature Valid I or new members only. Foreign applicants will receive special ordering instrtjcikMis. Canada must remii in U S, currency This order subject to acceptance by Ihe How-To Book Ciub. RP1H12BC 3174P S10.95 3404 526.S5 Counts as 2 BUILD IT RIGHT SupwJiilrjg thi. Can H-uftJOn trt '■■■|jr Hf-n TABLE SAW 800 K mi 2739P 516.95 3433 £24.95 Decks & Patios Outdoor LMra Sp*OM WOODWORKING , 1 Toehmquen. Up*. 1 and Shortcut from a Master CrariwTiflfi J IF^^I i JL i 3326 526.95 Cijijr' 5 as 2 3255 526.95 Count* » 2 3334 31695 11364P $10.35 i RETAINING WAUS 3263 JS7.95 Counts » 2 291 a 111.95 r "home electronics FIX II BOOK J9I2P »H95 5: 1990 HOW-TO BOOK CLUB Jr Btu* Rldgo Summit. PA 17294-0800 25 9 IP $17,95 O m o m CD m 3 8 CIRCLE 185 ON FREE INFORMATION CARD ASK RE Write to Ask R-E, Radio- Electronics, 500-B Bi-County Blvd., Farmingdale, NY 11735 w o z o en hi _i til 6 o VOLTAGE CONVERTERS I have a bunch of tools and some stereo equipment that was designed to run on the standard European supply of 220 volts, 50 Hz AC. Isn't there some way I can easily make, buy, or otherwise ac- quire a transformer that will let me operate those devices off 120 volts, 60-Hz AC?— A. Sfakianos Placitas, NM There are lots of place9 to get transformers that turn 220 volts AC into 110 volts AC, and they should work when their supply connections are reversed as well, but only for the voltage, not the frequency. You indi- cated in your letter that the frequency difference wasn't important for the equipment you wanted to use so I don't understand why you're having so much trouble. There are two basic types of com- mercially available converters used for converting 220 volts AC to 1 1 volts AC, and they're sold in just about every electronics store; even Radio Shack carries them. With a transformer I use, I can turn the sup- ply leads around and step up the line voltage from 1 1 volts AC to 220 volts AC (actually 120 to 240). There isn't any problem in doing that as long as you make sure you have the right type of voltage converter. Converters are made with either transformers or diodes. You can tell the difference between them when you're looking at the package by the weight and the wattage rating. Trans- former-based converters are much heavier than the diode-based ones and usually have a maximum rating of about 50 watts or so. The package information should list them as being suitable for electronic equipment, battery chargers, camera flash units, and so on. Since there's a trans- former inside the package, the volt- age is actually divided in half, Cor doubled, when you use it backwards). The output of those converters is a sinusoid. Diode-based converters are much lighter, and even though the package is the same size, they usually have a maximum rating of 1000 or 1500 watts. You'll find them recommended for things like heaters, lamps, and so on. If you try and use one of those appliances with a transformer oper- ated converter, you'll probably wind up destroying both the converter and whatever you have plugged into it. With the diode-based converters, you cant turn them around and ex- pect to double the input voltage. Generally, diode-based converters only produce half-wave rectified AC instead of a full sine wave, and they don't cut the voltage in half either. As with any diode voltage drop circuit, the output is .67 times the input volt- age. If you put 220 volts AC across the input, you're going to get about 148 volts AC at the output. That may not be much of a problem for most resistive loads, but you should realize that overdriving a heater is going to make it hotter than it was designed to be and that can cause a real problem, ALARM SYSTEM BACKUP I've designed an alarm cir- cuit for my house that's powered by line voltage but I want it to switch over to back- up batteries if and when the power fails. The control part of the circuit is the only section that has to be constantly powered. I'm not worried about lights and other high current devices since I have a commercial unit for that part of the system. Do you have a simple circuit that can provide the battery backup? I only need 100 milliamps or so. — G. Benjamin Indianapolis, IN Having a fail-safe power-supply for a home alarm system is a good idea and, if you think of it, is probably the most important part of the alarm sys- tem. Fortunately, it's also one of the easiest things to add to the circuit. In your case, it's even easier, since you designed the alarm-control circuit yourself. There are several ways to add a battery backup to a circuit, but since you're only looking for 100 milliamps. you can keep it simple and the back- up circuit can be made so small you'll be able to easily find room for it in your existing enclosure. The circuit shown in Fig. 1 is a sim- ple design that can do the job. When the line voltage is available and oper- ating, D2 is reverse- biased and cur- rent flows into the batteries through R1, the current limiter for the nickel- cadmium CNi-Cd) batteries, or what- ever type of rechargeable battery you want to use. If the main power is dis- connected (inadvertently by you or intentionally by a burglar), D2 is for- ward-biased and battery power is available for the alarm circuit. By adding D1 to the circuit, you can keep the battery from powering other cir- cuitry that's not essential to keeping the alarm system active. \+/0-/iUVDC -W- o. WAOOJ /NV-QO) re aiamm -o s ystem co/smoL capa c/ro/t, V017AGE DEPEM05 OH BATTERY AND SYSTEM VOtLTA&E t B/ | C&ECS/AR.GEA&LE- 3A TTEijfZ/E S ) ~ ^see 7MXT~ FIG. 1— THIS SIMPLE BATTERY backup circuit can be used to power a control circuit for art alarm system. The particular diode you should use for D2 depends on the amount of power you want to draw from the bat- tery when the main power is discon- nected. If you're sure that you'll never need more than 100 milliamps, you can probably get by with a small 1N914 diode but, if there's a chance you might draw more current, or you just want to play it safe, you're better off with something like a 1N4001. If you use Ni-Cd batteries, you'll need a constant trickle-charging cur- rent. You should select R1 to limit the charging current to the battery's C/10 rating, which is 10% of the ca- Discover Your Career Potential In The Fast Growing Field Of High-Tech Electronics! CIE Gives You The Training You Need to Succeed... At Your Own Pace...& In Your Own Home! If you're anxious to get ahead ...and build a real career... you owe it to yourself to find out about the Cleveland Institute of Electronics! CIE can help you discover your career potential in the fast growing field of high-tech electronics. 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CIE World Headquarters xS>' Cleveland Institute ol Electronics, Inc. 1776 East 17th St., Cleveland, Ohio 44114 D YES! Please send me your independent study catalog (For your convenience, CIE will have a representative contact you— /here is no obligation.) Flint Name . Apt# Area Code/Phone No. Bill bulletin on educational benefits: a Veteran a Active Duty Mail This Coupon Today! ARE-183 o m CD m J} CO [0 O 11 introd^ e V»- in inc luding Phase Shift Circuit using built-in oscilloscope Easy to use, menu-driven, mouse controlled circuits come alive on your terminal! 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Now, you can build and experiment with actual circuits, choosing from an unlimited number of components, including resistors, capacitors, inductors, general impedence, AC voltage sources, batteries, AC/DC current sources. Then, analyze your circuits with buflt-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 book, featuring over 75 experi- ments and circuits. Enjoy countless hours of fun, while learning. And, you won't blow up your "lab", because 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 current flow using built-in a mmete r/vol t meter PROTOLAB provides a complete lab station of high tech equipment including... Parallel Resonance LC Tank Circuit using sweep generator to vary voltage across lank, monitoring circuit response Voltmeter ; Ammeter Frequency Generator Frequency Compensated Bridge using oscilloscope to measure AC signal offset by DC voltage Order today... start building and testing circuits today... Complete, for IBM/compatibles*... ONLY $99^ For Macintosh with high resolution, enhanced graphics**.. 512995 'IBM/compatibles require 3B4K RAM. CGA [640x200] video display and mouse •Macintosh requires Macintosh 51 ?E. MAC XL. MAC PLUS. MAC SE, MAC II Includes lab experiment book and exclusive PROTOWARE™ Call toll-free for details GLOBAL 1-800-572-1028 SPECIALTIES Global Specialties. 70 Fullon Terrace. New Haven, CT 06512 Telephone; [203] 624-3103. ; Interplex Electronics, 1990. All Global Specialties bread boarding producls made in USA CIRCLE 189 ON FREE INFORMATION CARD Building the best DMM for the money is no accident The new RMS225 was carefully designed to give you what you wanted at a price you could afford. Visit your local distributor today and you'll agree the choice is obvious. Fluke Model 77 3-Vfe Digits 3,200 Counts 0.3% Accuracy Touch Hold 8 31 Segment Analog Bar Graph 2,000 HourBattery Life 10A Range ifusmi Protective Holster 3 Yr. Warranty S159* w O z O or. LU 6 Q < 14 • Touch Hold is a registered trademark of the John Fluke Mfg. Co., Inc. "1990 Fluke and Philips Catalog Bsckman Industrial " An Arf/l/ate ot Emersofi Electric Co. Instrumentation Products Division 388? Ruffin Road, San Diego. CA 92123-1893 (619) 495-3200 • FAX (619) 168-0172 • TIJC 249031 Outside California 1-800-854-2708 Wilhin California 1-800-227-9781 © 1990 BtdoiHii Industrial Corporation. Spreiflcaikons suo)ki to change without notice. Fluke is a fegjstonl trademark ot)tfin Flute Mftv Co., hie. JNIB0O1-12W CIRCLE 98 ON FREE INFORMATION CARD pacity of the battery. In aC/10 rating, "C" is the charge capacity in amp- hours, and "10" is the number of hours the battery can supply useful power. Therefore, the capacity divid- ed by that operating interval equals the maximum current safely drawn from or supplied to the battery. The trickle current charge, l c . must be less than or equal to the maximum safe current drawn through the bat- tery. The value of R1 can easily be calcu- lated using R1=[(V c -(0.6 volts + V b )]/I c where V c is the circuit voltage. V b is the battery voltage, and l is the charging current. This is just a straight application of Ohm's Law. The reason it seems more complex is that you have to sub- tract the 0.6 volt-diode drop and bat- tery voltage from the supply voltage. The capacitor in the circuit is used to filter any voltage glitches and also to provide a few seconds of power if you want to change batteries. TWO HARD DISKS I have an AT-class computer with a hard disk and am trying to add a second hard disk. The controller card can work with two hard disks, but I'm not having any luck connecting the cables. No matter what I do, the computer never recog- nizes the second hard disk. — W. Meredith Philadelphia, PA If you're installing the second drive simply to increase capacity, maybe you should consider buying a single new hard drive with at least double the memory of your present one. Not only will that give you extra room in- side your cabinet for other add-ons such as tape drives, but you might also benefit from increased overall operating speed — your old drive may not be as fast as the newer ones. You can keep your old drive for emergen- cy backup, or you can sell your old drive to someone who doesn't have one. However, if you 're determined to add a second drive, read on. In order to have two hard disks in your computer, you have to tell the computer the second hard disk is there and then you have to cable it so the computer can find it. Since you have an AT computer, you have to run the setup utility and set the correct type for the second hard disk. How that is done depends on the BIOS you have since some of them have the setup utility in ROM while others require that you run a program on a disk, such as the IBM AT diagnostics. Be sure and set the type correctly since an incorrect number there can damage the hard drive. Once you have that done, you have to physically connect the drive to the computer and that involves four things: 1 . A power cable has to be connected to the drive. 2. A separate data cable Cthe thin one) has to be connected from the controller card to the drive. 3. The control cable Cthe fat one) has to be connected to the drive. 4. The drive select jumpers on the back of the hard drive have to be set to match the type of control cable you're using. The first two operations are simple and just about the only thing you have to watch out for is the cable's orienta- tion. Pin 1 on the controller card has to be connected to pin 1 on the drive's edge connector. The last two items on the list go together since the drive select jumper on the back of the disk has to be set according to the type of con- trol cable you're using. The first hard disk in the system, (your original one), should be at- tached to the connector at the end of the control cable and the second hard disk, (your new one), should be at- tached to the connector in the middle of the cable. If there's a twist in the wires be- tween the connectors for the two hard disks, the drive select jumpers for both hard disks should be set in the second position (sometimes marked as DS2.) If there's no twist in the cable, the drive at the end (your original one) should have the jumper set in the first position and the drive in the middle of the cable, (your new one), should have the jumper in the second position. The terminating resistor should be removed from the new drive in the middle of the cable and left on the original drive at the end of the cable. If you can't find the terminating resistor or have a hard time trying to remove it, don't worry about it. I've seen sev- eral machines in which both drives had the terminating resistors left in and everything worked fine. R-E Countersurveillance Never before has so much professional information on the art of detecting and eliminating electronic snooping devices — and how to defend against experienced information thieves — been placed in one VHS video. If you are a Fortune 500 CEO, an executive in any hi-tech industry, or a novice seeking entry into an honorable, rewarding field of work in countersurveillance, you must view this video presentation again and again. Wake rip! 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 up! If you are not the victim, then you are surrounded 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, ot cable. It presents an informative program prepared by professionals in the field who know their industry, 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. Foiling Information Thieves Discover the targets professional snoopers seek out! The prey are stock brokers, arbitrage firms, manufacturers, high-rech companies, any competirive industry, or even small businncsses in the same community. The 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 CALL TODAY TOLL FREE 1-800-522-6260 HAVE YOUR VISA or MC CARD AVAILABLE what was to be an embassy and private residence into the most sophisticated re- cording studio the world had ever known. The building had to be torn down in order to remove all the bugs. Stolen Information The open taps from where the informa- tion pours out may be from FAX's, com- puter communications, telephone calls, and everyday business meetings and lunch time encountets. Businessmen need counselling on how to eliminate this in- formation drain. Basic telephone use cou- pled with the users understanding that someone may be listening or recording vital data and information greatly reduces rhe opportunity for others to purloin meaningful information. RAOLO-EI.ECTRONICS VIDEO OFFER RE 10O-B IS i -County Blvd. Humirigd»le, NY 1 1 7 45 Piease rush my eopy t>T the Count£f5UfVcU1ttU£ Techniques Video VHS CftSSWtt tor S49.yS plus 54. (HJ lor postage and handling. No. ot Cassettes ordered Amount of payment S „ Hill my □ VISA U MasterCard Card No. llxpirc Date / Signature Name Address City , State , . ZIP. A]] payments in U.S.A. funds. Canadians add %-i.W per VHS cassetrc, Mo foreign orders. New York Srare residents add applicable sales tax. 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 rhe unwanted listener, and the technique of voice scrambling telephone communications. In fact, do you know how to look for a bug, where to look for a bug, and wfiar 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 ro fool yon inro believing you found a bug and secured the telephone. The sec- ond bug placates the investigator when he finds the real thing! And the third bug is found only by the professional, who conrinued ro search just in case there were 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- rers u rve i 1 1 an ce prbfes s i o n a I , The professionals viewed on your tele- vision screen reveal information on the latest technological advances like laser- beam snoopers thar 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 tape in the pri- vacy of his home. After 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 $350-750 and possibly pay hundreds of dollars more if you had to travel to a distant city to D attend. Now, for only §49.95 (plus g $4.00 P&H) you can view Countersur- ™ veillame Techniques at home and take ro refresher views ofren. To obtain your jD copy, complete the coupon below or call ^ toll free. o 15 LETTERS Write to Letters, Radio- Electronics, 5QQ-B Bi-County Blvd., Farmingdale, NY 11735 LOGIC ANALYZER REANALYZED The review of the Photronics low- cost logic analyzer (.Editor's Work- bench. Radio-Electronics, Au- gust 1990) does a terrible injustice to the product in stating that its "low speed" and "8-bit operation" are in- sufficient. That fact is that its speed and data width are usually more than adequate for the application areas for which it was designed. The LA1 is primarily intended for digital troubleshooting in areas that require more than a dual-trace os- cilloscope, a digital voltmeter, and a logic probe while not requiring the power, expense, and complexity of a typical logic analyzer designed for mi- croprocessor applications. When an actual situation places the designerin that predicament, the need for a me- dial solution becomes obvious, A few examples that prompted the design of the LAI are stepper- motor logic circuits, remote-control circuits using the popular 40-kHz IR encoding, and countless applications in the non-mi- croprocessor prototype circuits breadboarded by the professional as well as hobbyists and students. Many of those applications do not require all eight data channels or the full bandwidth of the LAI. Perhaps the label "logic analyzer" automatically conjures up the thought of complex, high-speed, wide-bus mi- croprocessor analysis; nonetheless, that is the most appropriate label for the LAI, which completely accom- plishes its design goal by introducing a cost-effective means of obtaining that worthy capability at the other end of the spectrum. DALE NASSAR PRESIDENT, PHOTRONICS Amite, LA Perhaps I should have said "insuffi- cient for the things people normally g use logic analyzers for, " which does z not include IR decoding, stepper- £ motor circuits, and so on. I liked the o device quite well as a teaching aid, 3 but I remain skeptical of its utility out- 5 side the educational environment. 5 That is not to denigrate the device; a a: balanced review must point out both the strengths and the limitations of a product. — Jeff Holtzman, Computer Editor CABLE SCRAMBLING I read with interest Robert Grossblatt's Drawing Board column, entitled "Scrambling and Macrovi- sion," in the July issue of Radio- Electronics. I am only sorry that, as a new subscriber, I have missed some very important information in earlier Issues. However, having worked for the "Phone Factory" for a number of years before retiring, I am well ac- quainted with COAM (customer owned and maintained) equipment and the pitfalls of the "rules." With divestiture, as Mr. Grossblatt said, we can now connect "most any- thing" to the line on the COAM side of the RJ block— as long as it doesn't "upset" or interfere with the net- work. Cable TV, as a franchised com- pany, should operate under the same rules. If they do not want a channel to be available to me, then they shouldn't put it on the network to begin with. The power company doesn't say that you have to pay higher rates if you have a microwave oven, hair dry- er, TV. etc., and I see no reason for any utility to have special con- cessions. So if they don't want me to have what is on the network, then don't provide it and trap it out — make me the responsible party, not them. DELBERT McMULLEN Independence. MO THE "LONG RANGER" I am responding to the article "Whatever Happened to AM Radio?" (Radio-Electronics, September 1990). After 38 years as a small-mar- ket chief engineer and announcer, I feel I have some understanding of AM/FM radio. A new business climate exists to- day. Most business firms in this rural area are chain outfits. They advertise little on radio. FM or AM, Ten years ago almost all were Mom-and-Pop concerns and, though some didn't contribute heavily, nearly all adver- tised, TV and cable were no competi- tion for commercials then or now. But they have captured a large portion of the audience. Today, the weekly newspapers, shoppers' guides, and sales flyers get the bulk of advertising dollars. There are too many AM stations, especially at night. We can receive a half dozen that are relatively free from interference. But one picture is worth a thousand words, so we watch TV at night. And some areas have too many stations, in the day and evening. The National Association of Broad- caster's (NAB) grand scheme to in- stitute the National Radio Systems Committee's (NRSC) pre-emphasis to AM is largely a wild idea, in my opinion, and will cause additional in- terference (albeit some improvement in the cheap sets with poor audio quality). The plan is to change back in the future, removing pre-emphasis. Why not attack the problem head on? Yes, even manufacture our own re- ceivers if the Japanese won't cooper- ate. We have the know-how. the facilities, and plentiful parts. AM radio, as we old-timers re- member it. is gone. But with some prudent managing it is far from dead. In fact, we just might see an AM re- surgence in the future — it is definitely the long ranger! GENE VINSON Thomasvilte, AL MORE ON AM RADIO Mr. Dexter's article about the prob- lems facing AM radio contained a se- rious technical error. Mr. Dexter wrote that AM transmissions are lim- ited to a bandwidth of 10 kHz, and an audio response upper limit of 5 kHz. Actually, the FCC has always allowed AM stations to transmit audio out to 15 kHz (the same as FM radio), with a corresponding RF bandwidth of 30 kHz. AM radio's poor sound quality is because almost all AM receivers have a 10-kHz bandwidth, limiting re- ceived audio response to 5 kHz. When broadcasting began, there was no such thing as "high fidelity." 16 INTERNATIONAL, INC, ORDER TODAY! 1-800-729-9000 THE "GREAT DEAL " CATALOG 286 AT COMPUTER with 14' 1 HIGH RESOLUTION VGA COLOR MONITOR & 30MB HARD DRIVE 80286 microprocessor, 2.5/6.25MHI switchable. One MB RAM on mother- board, expandable lo four MB. ■ 30 MB hard drive. ■ One 5.25" 1 .22MB (loppy drive. - High resolution VGA monitor: 640 x 480. ■ Socket for 80287 malh co- processor, ■ 16- bit VGA card; 800*600 res. 3 expansion slots — two 1 5-bit & one IBM compatible- ■ 1 serial port. • 1 parallel port. 8-bil PS/2 compatible 5-pin mouse port. Real time clock/calendar. Phoenix 28S ROM BIOS. AT style 1 01 -key enhanced keyboard. * Includes MS- DOS 4.01 wild DOS Shell utilities and GW BASIC". PCdim.:4-1/4"Hx 15"W X 15-1 CD. Monitor dim.: 13.9"Wx14.7"D x14.1"H. One Year Mfr. Warranty! Factory New! FHEE BONUS SOFTWARE: Spinnaker "Easy Writer* word processing. "Ace2" interaction game & "Splash* demo program Also includes coupon to buy "Splash" at great savings ' Mfr, Sugg. Retail: $2,293.00 damarkSQQQ 99 PRICE &&& Item No. B-2405-1 49047 Insured Ship/Hand.: S49.00 CORDLESS bsjOBK M ^ ; ;: * I nlrared wireless stereo headphone system wilh built-in rechargeable battery. - Comfortable s&mi open-air earpads. • Headphone rang©: up lo 23 leel. -Volume controls for left &. right channels. ■ Automatic level- control circuitry for crisp, clean listening. • Frequency response: 19 22,000Hz. ■ Sleek pyramid transmitter serves as a recharger too. Up to 6 hours o( operation per charge. - Japanese construction. * Lightweight, headphones only 4 01. ■ Easy to use — to listen just plug transmitter into your stereo, TV or VCR. ■ Includes AC adaptor and mini-plug adaptor. ■ Pyramid transmitter dim.: 9"H x 3-1/2"W x 4"D. ■ Model #: Mfr. Sugg. Retail: $199.95 DAMARK $-4 OQ99 PRICE I ^U Item No. B-2405-14S023 Insured Ship/Hand.: $6.50 MDFWF5K, ■ One Year Mir. Warranty! • Factory New! XEROX FAX TELECOPIER ■ Send and receive documents-dimply hook up your telephone to Ihe fax. ■ Send a portion ol a document or I he entire document I * Select from fast or standard sending speeds. l Test Document feature allows you to check for copy quality problems. ■ Group II compatible. • Jam removal function. ■ Ready lamp informs you to load document. * Fast sending speed: 4 minutes. 'Fault lamp indicator. ■ On-line lamp Indicates machine is connected to phone line. • Documents sent can befrom8to8-1fi-W x S to 1 1-3/4-L. Mfr Sugg pj etaj | j| new: ■Model*: 455. *„ „„„ __ • Dim.: Appro*. $2,199.00 18" X 18" X 5-1/2". *,^. — ■ • Factory serviced. DAMARK $OQQ99 but like new! PRICE £.*jZj • m Da " Warrant V ! lte m No. 8-2405-1 17556 Insured Ship/Hand: $20.00 Southwestern Bell Freedom Phone CORDLESS SPEAKER PHONE FF1700 Range: appro*. 1000 ft. with built-in range extending antenna, 48/49 MHx duplex. Cordless. Integrated speakerphone with volume control. 2 separate keypads; one on handset and one in base. * 9 number auto dialing plus auto radial * Quill- in two-way intercom with hold. * 10-channel selectable. Pulse/tone switchable. * Digital coded security. ■ Slatus-indioator lights. * Includes 3 rechargeable nickel cadmium batteries. ■ Snap-out battery pack. ' Color; Almond. ■ Dim.; 1 0"D x 2-1 CT x 6-1 /2"W, Model #: FF-1700. 'Factory serviced, but like new. 90 Day Manufacturer's Warranty! Mfr. Sugg, Retail if new: $179,95 DAMARK $7Q99 PRICE I J7 Item No. B 2405-1 50680 Insured ShipVHand.; S7.00 QiWMI-M 24-PIN DOT MATRIX ■hn i ll-T . l p mN TER •24-pin letter quality printer. - Print speed: 216 CPS draft: 72 GPS letter quality. 32K buffer. « Includes: 12Mulli- Strihe Ribbons PLUS 2 Font Cards-no choice on Tent cards received. ■ Built-in rear tractor. ■ Friction teed. ' Auto loading, single srieet guide for letterhead & cut sheets & Motion lead. « Front panel LCD display includes; type fonts, pitch, emulation, lines per inch, quiel mode and page length. ■ 360 x 360 graphics. ■ Tractor feed and tear bar lor continuous terms. • IBM emulation, ■ Single or continuous feed paper loading. » Parallelfserial ports included. « Model #: P321SL. • Dim.: 16.3"W x 3.9 "H x 15'D. - 1 Yr, Ltd, Mfr, Warranty! • Factory New! Includes printer ribbon & font cards. Sheelfeeder • Model #; MS -17. Mlr.Sugg.. $349.00 MFr Sugg. Retail: $1019-00 DAMARK$AQ99 DAMARK $ OQQ99 PRICE ^^ PRICE &99 Item No, 8-2405- M9450 Insured Ship'Harttt. : S6.00 Hem No. B-2405 1494&S Insured Stiip'Hand-: 529.00 <£martMap No need (or a dedicated fax In*. Fax/phone auto switch allows your new fax lo share existing phone line. * Works On Group 3 fax machines, Single switch to lock out either voice or fax calls- Front panel status lights indicate modes of operation. SmartMax handles power outages by automatically switching to phone-only mode. Allows manual override so you can send a lax to Ihe person you're talking to on the phone. 24-Hour customer sen/ice line. * Easy installation. U.L. listed. Mfr. Sugg. Retail: $245.00 DAMARK $QQ 99 PRICE 17 57 Item No, B-2405- 128934 Ensured Ship/Hand.: $7.50 FCC certilied. Dim.; 4"x7" x 1-1/2". Wt.: 2-1/2" lbs. Model*: MX 1030 2 Vr. Mfr. Warranty! FOR FASTEST SERVICE CALL TOLL FREE r 1-800-729-9000 C * QTY CUSTOMER SERVICE: 1-612-531-0082 NAME ADDRESS, CITY PHONE DESCRIPTION ITEM* smn -ST- ZIP. DELIVERY TO 48 U.S. CONTINENTAL STATES ONLY L— I □ CARD MO, EXP. DATE SIGNATURE SUB TOTAL l~l in MM add 6% Sales Tax Total sm/\ □ Check/Money Order ghand total PRICE Send To: DAMARK INTERNATIONAL, INC., 7101 Winnetka Ave, N., Minneapolis, MN 55428-1619 B-240.5 Copyright 1990. DAMARK International. Inc. All rights reserved o m Do m J} CD and ask about our exclusive VA62A instrument evaluation program. Tech-Tape Video Preview and FREE full line coloi catalog are also available. 3200 Sen core Drive, Sioux Falls, SD 57107 100% American Made CIRCLE 194 ON FREE INFORMATION CARD a m o m u> m 30 27 m\ft! SPECIAL $59.95 Reg.48&60" Model REIM5 • Two removable pallets hold over 60 tools • Case top has built-in document holder • Case bottom is partitioned into 3 areas A handsome black case to organize and transport your valuable tools and instruments. This is the same quality case used by literally thousands of professional field engineers. Case is made of high impact polypropylene, and has snap-action keylocks and a padded handle. Size:17V 2 " x 12'/ 2 " x 5". Tools are not included. Offer expires January 31 , 1 991 . To order call: 1-800-225-5370 In MA: (508) 682-2000 Same Day Shipment! Money Back Guarantee! Terms: Visa, MC, Amex; RO.'s from qualified firms accepted. Add $5.50 for packing and delivery FREE CONTACT EAST CATALOG Co ntains th ousan ds of prod u cts fo r test i ng , repai ri n g & assem b li n g electronic equipment. To get your free catalog, call (508)682-2000. LOGIC ANALYZERS. Philips PM3580/PM 3585 family of logic analyzers feature quick set-up time — users need less than 30 minutes to get an instru- ment up and running. Pop- up menus and VGA graph- ics offer a simple interface for new users, and provide experienced users with short cuts for quick opera- tion. Faster analysis is ob- tained by reducing state and timing measurements to one probe connection, requiring only one set-up to be learned, and providing fully-integrated state and timing triggering. All mea- surements are time tagged with up to 5-nanoseconds resolution. CIRCLE 21 ON FREE INFORMATION CARD The logic analyzers fea- ture a unique dual-analyzer- per-pin architecture that al- lows both state data (relat- ing to software functioning) and timing data (relating to hardware performance) to be acquired from the sys- tem simultaneously on up to 96 channels, using just a single set of probes. Perfor- mance specifications are 50- MHz state, up to 200- MHz timing, and 2 kilo- bytes of memory per chan- nel. Windows allow the display of state and timing or two views of state or tim- ing data. Other features include a large, high- re solution screen, a video-output socket for connection to an external large-screen VGA monitor, and a parallel- printer port for hardcopy output. Also provided is an RS-232 serial port for diag- nostic testing and future options, and BNC trigger connectors for easy trigger of other instruments, or for external triggering of the logic analyzer from another instrument. The PM 3580/PM 3585 family of logic analyzers ranges in price from $4,250 for the PM 3580/30 with 32 channels of 50-MHz state recording and 32 channels of 100- MHz timing and 1K deep memory, to $10,950 for the PM 3585/90 (pictured), which offers 96 channels of 50-MHz state and 96 chan- nels of 200-MHz timing re- cording with 2K memory. — John Fluke Mfg. Co., Inc., P.O. Box 9090. Ever- ett. WA 98206; Tel; 800- 44-FLUKE. ext. 77. DIGITAL SIGNAL PRO- CESSING BOARD. Daianco Spry's model 250 digital signal processing (DSP) board has analog and digital inputs and out- puts for the PC/AT and bus-compatible microcom- puters. The board is based on the 40-MHz Texas In- struments' TMS320C25 DSR and can accommodate the faster TMS320C25-50, the EPROM-based TMS320E25. and the new- er TMS320C26. The model 250 can be used in stand-alone mode in em- bedded systems when equipped with the TMS320E25. The DSP board provides data ac- quisition for eight single- ended channels at 12-bit resolution and a maximum 300-kHz sampling rate. Two analog-output chan- nels are provided, as are a buffered digital I/O expan- sion connector and the se- rial (codec) interface of the Tl DSP. The board can be populated with up to 64K words of zero-wait-state program RAM and up to 128 words of one-wait- state data RAM. The data RAM is simultaneously available to both the PC CIRCLE 55 ON FREE INFORMATION CARD CIRCLE 22 ON FREE INFORMATION CARD and the TMS320 DSP through the use of an on- board memory controller. The model 250 features high throughput and is easi- ly accommodated in multi- ple-board systems. PC-to- data RAM -transfer speeds may be as high as 3 mega- bytes per seconds. The maximum continuous throughput to disk is thus limited only by the ca- pabilities of the host PCs disk system. Software that is bundled along with the model 250 includes as- sembler, debugger, FFT's, signal and spectrum dis- play, digital filter examples, record and playback to and from disk, and a waveform editor. The model 250 digital signal processing board is priced starting at $1095 (40-MHz TMS320C25, 4K words of program RAM, and 32K words of data RAM). — Daianco Spry, 89 Westland Avenue, Rochester, NY 14618; Tel: 716-473-3610. HANDSHAKING MO- DEM. Offering full-duplex data transmission at rates of upto19.2kilobandanda bi-directional control sig- nal — all over two twisted pairs — Teiebyte Tech- nology's model 204 Hand- shaking Modem can pro- vide a "hardware hand- shake" for devices such as laser printers and various terminals. The "handshake" is typ- ically used when terminals are connected to a PBX switch, which uses the handshake to determine if the terminal is active or if its power has been turned CIRCLE 23 ON FREE INFORMATION CARD off. Housed in a small plas- tic case, the full-duplex modem measures only 2 x 2%x 3/4-inches. The model 204 samples clear-to-send (pin 4), re- quest-to-send (pin 5). and transmit data of the RS-232 serial interface, and derives its operating power from them — no bat- tery or external power sup- ply is required. The stan- dard-data I/O occurs on pins 2 and 3 of the RS-232 connector. The control sig- nal uses DTR (data termi- nal ready) as the hand- shake input and DCD (data carrier detect) as the hand- shake output. The input and output are switchable, to accommodate connec- tion of the modem to either a DTE or DCE device. The control signal input also controls the data flow from the modem. Data can be transmitted when the con- trol signal is high. The modem requires no sepa- rate power inputs. Data transmission be- tween modems uses dif- ferential baseband signal- ing techniques, and com- mon-mode signal rejection capability is greater than 20 volts. Those features are there to allow error-free op- eration in all kinds of noisy environments. The model 204 costs $89.00 in unit quantity and $68.00 in quantities of 100.— Teiebyte Technology Inc., 270 East Pulaski Road, Greenlawn, NY 11740; Tel: 1-800-835-3298 or 516- 423-3232; Fax: 516- 385-8184. R-E The ry*\ ■ u|timate ' n Heath bme Control Just imagine, one press of a button and you can turn off your stereo, turn on your TV and VCR, start a videotape, and dim the lights. The best part is you've done it all from your favorite chair. The One For All remote Whole House Controller, Command Center and Lamp Module make it all possible. Installation is a snap. The remote Whole House Controller operates virtually any infrared- connolled device, and when used with the Command Center can control lights throughout your house. Just point the remote Whole House Controller at the Command Center and press a button. You've got home eonnol. 'V (SB Expand your reach to additional lights and small appliances with other X-10 modules available from the Heath Catalog. Call 1-800-44-HEATH for your FREE copy. Order Today $119.95* Use Order Code 601-044 when ordering the One For All System URS-6000. Call Toll-Free 1-800-253-0570 * Price does not include shipping and handling, or applicable sales tax for Ml and CA deliveries : ^^J ^ © 1990 Heath Company. Benton Hiirbur, Ml ■ Lamp Module Controller Command Center CIRCLE 86 ON FREE INFORMATION CARD O m o m CD to to o 29 NEW LIT Use The Free Information Card for fast response. m o z o w < ELECTROMECHANI- CAL DESIGN HAND- BOOK; by Ronald A. Walsh. TPR, Division of TAB Books Inc., Blue Ridge Summit, PA 17294-0850; Tel. 1-800- 233-1128; hardcover; $49.50. The fields of electrical and mechanical engineer- ing are closely linked in the design and development of today's manufactured products. This book fills an important gap in the librar- ies of engineers and de- signers whose work re- quires them to cross the boundaries between elec- trical and mechanical de- sign. Including information about both disciplines, this well-organized book pro- vides practical product-de- sign data, working pro- cedures, and formulas in one comprehensive vol- ume. The broad range of subject matter covered in- cludes the following: spring design; standard fasteners and bonding methods; pro- totype construction; prod- uct liability, testing, and patents; basic pneumatic, hydraulic, air-handling, and heat equations and their uses; sheet-metal design and layout; and the selec- tion of bearings and gears. In-depth treatments of fre- quently encountered top- ics are also presented, including descriptive ge- ometry statics and dynam- ics, the fundamentals of circuit design, electronic components, fabrication techniques, drives, and linkages and mechanisms. The book provides real- world examples and more than 500 detailed illustra- tions. The emphasis throughout the pages of CIRCLE 11) ON FREE INFORMATION CARD this handbook is on the practical design data needed in the day-to-day development of parts, mechanisms, and assem- blies. '90/'91 CATALOG; from Parts Express Interna- tional Inc., 340 East First Street, Dayton, OH 45402; Tel: 513-222- 0173; Fax: 513-222-4644; free. Packed full of electronic parts and accessories, this catalog will interest both professionals and hob- byists. In its pages are ca- pacitors; resistors; speak- ers and accessories; semi- conductors; connectors; wire and cable; TV, CATV, and VCR repair parts; tech- nical books and sche- matics; alarm equipment; tools; chemicals; switches; and computer accesso- ries. (Customers outside the U.S. and its territories must send $5.00 for postage to receive the Parts Express catalog.) MONITOR POCKET GUIDE; from Display Technologies, Inc., 1355 Holmes Road, Elgin, IL 60123; Tel. 708-931-2100; Fax: 708-931-2120; free. This 4 x 9-inch brochure contains complete infor- mation on 7V2- and 9-inch color monitors and mono- chrome models that range in size from 5 to 21 inches. The guide includes easy-to- reference tabbed cards that list specifications such as CRT size, video and power inputs, horizontal CIRCLE 11 ON FREE INFORMATION CARD CIRCLE 12 ON FREE INFORMATION CARD and vertical frequencies, and bandwidth, for each of Display Technology's prod- ucts. Available options are also listed, and mechanical drawings of the products appear on the back of the cards. Highlighted in the brochure are the Color Pix.L monitors, which fea- ture Sony Trinitron CRT technology. In addition, the pocket guide contains a listing of sales offices and guidelines for choosing a monitor supplier. BROADCAST DATA SYSTEMS: TELETEXT AND RDS; by Peter L. Mothersole and Norman W. White. Butterworths, 80 Montvale Avenue, Stoneham, MA 02180; Tel: 617-438-8464; hard- cover; $39.95. Data transmission over TV and radio channels — commonly called teletext CIRCLE 13 ON FREE INFORMATION CARD and Radio Data System CRDS). respectively — are becoming important as- pects of modern broad- casting technology. This book covers both estab- lished television and radio practices and the comput- er technology that is used in the teletext and RDS systems. Background in- formation concerning the development of teletext is presented, along with the data-signal format and cod- ing methods used. The various components re- quired to form a complete system are described. Other chapters cover such subjects as preparing and recording subtitles, the networking of teletext data signals and regional ser- 30 vice requirements, teletext decoders, and the re-trans- mission of decoded tele- text signals as a video signal. The measuring techniques required to maintain broadcast net- works and to test decoders for both teletext reception and data distribution are described. The recent de- velopment of RDS, which allows digital data to be combined with a VHF radio signal, is discussed. The necessary techniques for both coding and decoding the signal are explained, and various applications are detailed — including the use of RDS to provide a local traffic-information ser- vice by interrupting net- work programming. LOW-COST HIGH- QUALITY OSCILLO- SCOPE PROBES; from Avex Probes Inc. (API), 1683 Winchester Road, P.O. Box 1026, Ben- salem, PA 19020; Tel: 1-800-87-PROBE; Fax: 215-638-9108; free. A variety of monolithic and modular oscilloscope probes are featured in this six-page brochure. Product descriptions are accom- panied by photographs and specifications, and a handy cross-reference chart is in- cluded. Also highlighted in the catalog are a wide vari- ety of probe accessories, and a 40-piece connector/ adapter kit. GLOSSBRENNER'S COMPLETE HARD DISK HANDBOOK; by Alfred Glossbrenner and Nick Anis. Dvorak Osborne McGraw-Hill, 2600 Tenth Street, Berkeley, CA 94710; softcover with diskettes; $39.95. This encyclopedic vol- ume is filled with clearly presented information on hard-disk drives for com- puter users of all levels of expertise. The book in- cludes practical advice and convenient tips about se- lecting, buying, and install- ing a hard disk; loading and organizing the hard disk for j@F r 1TV0KAKSSSSS™ If Gtossbrcnner's Complete HARD DISK HANDBOOK 31 CIRCLE 14 ON FREE INFORMATION CARD CIRCLE 15 ON FREE INFORMATION CARD maximum efficiency; res- toration and recovery tech- niques; networking; and special formatting pro- cedures. The first section of the book is dedicated to a "Quick-Start Guide" to get readers painlessly started using their hard- disk drives. The ins and outs of using DOS are ex- plained in detail. The book describes how to avoid problems by following guidelines for mainte- nance, security, back-up techniques, and file recov- ery. Included with the book are two 5V2-inch floppy disks that contain nearly 50 programs, including tu- torials, software tools, and utilities. Money-saving cou- pons for many items are also provided in the back of the book. r-e CABLE - TV SIGNAL REMOVERS ■FOR ELIMINATION OF SEVERE INTERFERENCE ■FOR -CENSORING' OF ADULT BROADCASTS SPSII.M EUVHi. • ATTENUATION - 45 dB TYPICAL - BANDWIDTH - 4 MHz AT 5 dB POINTS • INSERTION LOSS - 2 (JB UODEL -UHIHG IWHf CHANNELS PA33BAND PRICE 3HIPPJHG 23H 50*6 MHz 2.3 for 6 rristflf ham) 50-300 MHz M0 HO SHIPPING or e.o.0. 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M RISET1ME ns LOADING PF M(J PRICE J 41^1 Swltctiibto iK'lGrXH 15V200 4 1.? 2*1-4 fjrj 14 1 10 35.00 4103 1* 25 4 1.2 1.4 45 1 30.00 4104 Hffl 200 4 1,2 1.4 14 10 33.00 4110 100* 250 4 1.2 1.4 7 100 40.00 4115 MASTER KIT INCL l£A. 4101, 4103, & 4104 89.00 B PROBE ft MASTER 4898 RONS0N CI. SAN 0IEG0, CA 92111 FAX 1613] 560-7354 D K o m 2 m to to o CIRCLE 179 ON FREE INFORMATION CARD 31 RADIO SHACK PARTS PLACE : " WHERE SANTA STOCKS HIS WORKSHOP! PARTS HOTLINE I Radio Shack has a huge selection of popular electronic components, Pius, we can special- order 10,000 items from our warehouse— ICs, tubes, semiconductors, phono cartridges and styli. even SAMS' manuals. Service is fast and there's no minimum order or postage charge. BATTERY HOTLINE In addition to our large in-store stock, we can now supply almost any currently manufactured consumer-type battery— for cordless phones, computer memory, camcorders, transceivers, pagers and more. Service is fast and there are no postage or handling charges. Studflnder, Ends guessing, easy to use I Senses changes in wall density to find wooden studs fast— also wires, conduit, pipes. Battery extra. #64-2825 19.95 ^J ia jjl tp ■ B 4I1HOOH £iv Bbt> DDDD qUBBD QDOHB QHQQQ Super Calculator! The EC-4035 makes electronics math a snap. Displays and computes with elec- trical units— V. A, mA, mW. 110 functions. #65-963 39,95 16-Plece Precision Tool Kit. Top- quality jeweler's-type philips, blade and nutdrivers plus hex keys and a torque bar Fitted molded case. #64-1961 10.95 100- Wall Soldering Gun. Pull the trigger for full temperature in sec- onds. Built-in light. The comfort- molded handle stays cool, UL listed AC. #64-2193 10.95 Ess m m £i ami GoUing Slarrcd NEW! SemicondL Our 1931 edition types and the Ra ments. #276-4014 Getting Started Forrest Mimsin.T tion to project bi #276-5003 ctor "Sub" Bool lists over 95,00 dio Shack replaci 3.9 ;. s- n n Electronics. E rte perfect in trod u Jilding. 128 page 2.4 s. 9 Engineer's Mini-Notebook ELECTRONICS STOCKING STUFFERS! Engineer's Mini -Notebook Series. By For- rest Minis 111 Great gifts I Project ideas and useful data in Mims' famous, friendly style- big diagrams, handlettered text. With tips and suggestions for further experiments. NEW! Science Projects. #276-5018 . . 1.49 Timer ICs. 555/556 ICs. #276-5010 ... 99? Op Amp ICs. #276-5011 1.49 Optoelectronics. #276-5012 1.49 Basic Circuits. #276-5013 1.49 Digital Logic Circuits. #276-5014 1.49 Communications Projects, #276-5015,1.49 Formulas and Tables. #276-5016 .... 1.49 Schematic Symbols. #276-5017 1.49 O Z o oc H o Q < EC 32 Pocket-Size Digital Multltester With Autoranglng. Super gift for anyone working with electronics. This tester folds, with its probes, to fit a shirt pocket. Features easy -to -read LCD display, continuity sounder. Measures to 400 volts AC/DC. 2 megohms re- sistance. 4V* x 2 >h x %ib" #22-171 39.95 (1) Universal AC Adapter. 3 -'..5 6, 7.5 or 9VDC output. With 6- piece Adaptaplug 1 set. #273-1650 12.95 (2) 11&-3VDC Motor. About 1Va" long. #273-223 99C (3) DC Pulsing Buzzer. Extra loudl #273-066 4.29 V -^ (3) Ifl / ^ [4) (1) NEW! Reusable Cable Ties. #278-1622 Pkg. of 10/4.99 (2) "Universal" Cable Clips, #278-1647 Pkg. 10/2.79 (3) NEWI In/Outdoor Wire Ties. #278-1652 Pkg, of 30/2,99 (4) Markers. 630 stick-on letters. #278-1650 Set/1.79 (1) Mini Audio Amp/Speaker, Ideal testbench amp, also great for com- puter voice/music synthesis. Battery extra. #277-1008 11.95 (2) Long-Life Xenon Strobe Tube. With data. #272-1145 3.29 (3) Halogen Flashlight and Lantern Bulbs. HPR50. 6-volt. #272-1189, HPR52. 3V. #272-1190 . . Each 3.9S (1) (2) (1) NEWI AC Sensor. Indicates pres- ence Of 70 to 440VAC without direct electrical connection. Safety first! #22-103 9.95 (2) NEWI Circuit Tester. 90-300V AC/DC. #22-102 1.99 (3> AC Outlet Fault-Flnder. 3-prong for grounded outlets. #22-101 . .5.95 Since 1921 Radio Shack has been the place to obtain up-to-date electronic parts as well as quality tools, test equipment and accessories at low prices. Over 7000 locations to serve you— NOBODY COMPARES Prices apply at participating Radio Shack stores and dealers. Radip Shack is a divis'on ol Tandy Corporation .Radio/hack AMERICA'S TECHNOLOGY STORE CIRCLE 78 ON FREE INFORMATION CARD THE INTERSIL ICM7216 frequency- counter IC's (models A-D) have an impressive array of functions. All have a high-frequency os- cillator, decade time- base counter, 8-decade data counter and latches, 7-segment de- coder, digit multiplex- ers, and 8-digit multi- plexed LED-display drivers. There are four mod- els; the 7216A and 721 6B are universal counters, capable of measuring input fre- quency, oscillator fre- quency, frequency ratio, period, and time interval, and can per- form unit counting. The frequency counter discussed here uses the 7216C with a com- mon-anode display (the 7216D is similar). It'll become one of the most versatile pieces of test equipment on your bench, and simply fun to use. You can build it for about $80. Circuit description Figure 1 shows the pinouts for all four 7216 versions: the 7216A/ B use two inputs for measure- ments like the ratio of two fre- BU1U) THIS BENCHTOP FREQUENCY COUNTER Add frequency-measurement capabilities to your workbench with this inexpensive counter. CARL BERGQUIST quencies. The 7216C/D use single inputs, but have external decimal point (exdp input) inputs (pin 13), and measurement in progress outputs (pin 2). The frequency counter sche- matic is shown in Fig. 2. IC2 de- cade counts the input frequency, stores the result in latches, driv- es an 8-digit multiplexed LED display, and blanks all leading zeros. While the internal os- cillator normally uses 10-MHz crystal XTAL1. an external source can go on J3 to pin 24 of IC3 (ext osc input). Some other 7216C fea- tures are display blanking, measure- ment holding, and dis- play test- reset. Since IC2 is de- signed for a maximum reading of 10 MH2,IC1. a 7490 decade counter, expands the range to 100 MHz by con- necting pin 1 (Bi N ) to pin 12 (Q A ) for the maximum count period. Pin 8 (Q c ) is tied to pin 28 (input a) of IC2 for measure- ment. For more expan- sion, IC3, a CD4017 decade counter, is an adjustable divide-by- N. As mentioned earlier, there are four ranges, and operation is possible with or without IC3. When S8 is set to out, IC3 isn't used, and the display reads 1:1, showing the actual undivided frequency of the input on Jl or J2 in kHz. Obviously, if the frequen- cy of the input goes below the nominal minimum possible for any given range, the display will read zero. % o § o LU _l LU 6 Q < IT 34 i CONTROL INPUT INPUT A INPUT B HOLD INPUT FUNCTION INPUT OSC OUTPUT DECIMAL POINT OUTPUT OSC INPUT SEG i | EXT OSC INPUT DIGIT 1 SEG G > OUTPUT SEGaJ 7216* *w SEG s ! SEGB SEGC segfJ OUTPUT DIGIT 2 OUTPUT ( DIGITS DIGIT DIGIT 5 RESET INPUT RANGE INPUT {DIGIT 6 DIGIT 7 DIGIT 8 28^ 27_ 26 •&_ ?i. S. 22 21_ 1°. [9 IS 17. i£ lj _3_ 4 _L JL 7 _6_ _9. 10 Jl Jg 13 1-! CONTROL INPUT INPUT B FUNCTION INPUT DIGIT 1 INPUT A HOLD INPUT OSC OUTPUT OSC INPUT OUTPUT EXT OSC INPUT DECIMAL POINT OUTPUT 721 K OUTPUT OUTPUT RESET INPUT RANGE INPUT OUTPUT JL 4_ 5. | 7 1 _9 19 H 12 13 14 CONTROL INPUT INPUT A HOLD INPUT ME ASUREMEN T IN PROGRESS DECIMAL POINT OUTPUT OSC OUTPUT SEGE ^ OSC INPUT SEG G > OUTPUT EXT OSC INPUT SEGA J ' DIGIT 1 DIGIT 2 OUTPUT 721 6C OUTPUT^ DIGIT 3 DIGIT 4 RESET INPUT EX. DP. INPUT RANGE INPUT OUTPUT la. a ?£ 25_ 24_ 23 21 1L 20_ II IS: 17 '.''■ !'■ J JL _4 -5J _6 _1 _8 _1 10 _M 12 J2 14 CONTROL INPUT MEASUREMENT > OUTPUT IN PROGRESS DIGIT 1 DIGIT 2 DIGIT 3 DIGIT 4 DIGIT 5 > DIGITS DIGIT 7 > OUTPUT DIGIT 8 J INPUT A HOLD INPUT OSC OUTPUT OSC INPUT EXT OSC INPUT DECIMAL POINT OUTPUT 4 o- DRIVERS^ 3 O- TO SEGMENT DRIVERS< ON FCZ fAO— M fe\ DISP1 1 ' It 1 r DISP2 j 1 j 1 ^ (3) FIG. 4— THE PARTS PLACEMENT DIAGRAM for the LED-display PC board. LED1 goes on the right end of the PC board as shown, with the cathode tacked to the foil itself (not a pad), and the wire groups for the segments and digits are shown. Most jumpers don't have separate foil pads, and are tacked onto pads used for other wires. LEFT DIGIT RIGHT DIGIT X X H 14 , . \™J- % t' MANB710 ®©($>®(f)©®(!)®(i) IIIIII ®® *i 1 1 i 1 1 T ■ni H 2 H 3 H 15 n 16 M 17 1-1 19 M 4 H 5 ti 6 M 7 t-t 8 '"< 10 H 11 J"f 12H 9^ *•-' ^_^ ^_' v • \ • * • ^ / ^—^ v,' vv v ^ \ / V V \ / v / \ s g z o EC I _l LU g c < rr 7 c 7 T T G T DP "" T B 1 T DP FIG. 5— PINOUTS FOR THE MAN6710 2-DIGIT, 7-segment, common-anode, multiplexed LED display. the display board. Several jum- pers must be tack soldered to the pads on the foil side of the display board. The reason Jl and J 2 are con- nected together is because in the prototype, the original plan (later abandoned) was to make a uni- versal counter, needing two in- puts to make full use of available IC functions. The parts dis- tributor the 7216C was obtained from thought version C was a universal counter. By the time the mistake was discovered, the front-panel holes on the cabinet had already been drilled. To avoid an empty panel hole, dummy RCA jack J2 was placed there, in parallel with Jl. Although Fig. 2 indicates that Jl is the one that's actually used rather than J2. either was usa- ble, but only one at a time. Ob- viously, you wouldn't need both jacks on yours, and should only drill one panel hole. The inputs on Jl and J2 were to have been "100 MHz" and "FREQ DIV," purely arbitrary titles stemming from personal preference. In the originally planned version, two 7490 decade counters were to have been used, one for each in- put. The finished frequency counter is shown in Fig. 6. Figure 7 shows an overhead view with the top open. A 470- ohm resistor was installed for R8, slightly above the center on the left side of the main PC board, but never used in the prototype. Instead, another 470-ohm re- sistor was placed off-board, in se- ries with LED2, behind where LED2 and its bezel fit into the front panel. The prototype really used four boards, but only the main and display boards had foils. The IC4 heatsink is of sheet aluminum, bent to fit in the cab- inet, with silicone grease used for good heat transfer, and C6 under- neath. In the prototype, 24-pin DIP sockets were used. The right- most piece was cut from a whole one, and has only six pins. Since the three sockets and the cut piece at right fit flush against one another, there's an unused hole between individual displays. To avoid cutting a socket, use 18-pin versions in yours. The 5-pin ter- minal strip is used as a feed point for the +5 volts from IC4. Figure 8 shows a closeup view of the LED-display PC board from the foil side. Since three holes were needlessly drilled for Jl— J3. there wasn't enough room left for S8, so a notch was cut in the lower left corner of the display PC board, clearly visible in Fig. 8. The wires to LED1 are at upper 36 J1 J2 (SEE TEXT) FIG. 6— THE FINISHED FREQUENCY COUNTER, shown in display-test mode, with all digits and decimal points lit. J1 and J2 are wired together, but one is unnecessary (see text). DSPt DSP4 R7 87 R8 (WRAPPED 1 IN TAPE) IC3 IC1 RS(UNUSED) 8 I S2 S4 S3 S1 S5 / S9 I se D1 02 (CATHODES ■ D3 AT RIGHT) ■ D4 T1 CENTER TAP(UNUSED) TERMINAL STRIP C6 |C4 (UNDER C5 HEAT SINK) FIG. 7— AN OVERHEAD VIEW OF THE PROTOTYPE; R8 on the main PC board wasn't used. Another off-board 470-ohrn resistor is in series with LED2, and 1C3 and IC4 were later added to the main PC board. The IC4 heatsink is sheet aluminum with silicone grease; C6 is underneath. The prototype had three complete 24-pin DIP sockets for the LED displays, and part of another, with an unused hole between displays; use 18-pin sockets in yours. The markings shown on D2 and D4 are wrong; the cathodes all point right. The terminal strip is a feed point for the + 5 volts from IC4. right; normal polarity is re- versed, with black going to the anode, and white to the cathode. Note the unused pads between individual LED displays, where they fit against one another on the component side. The prototype cabinet is 8 X6.25 x3-inches; drill the front panel holes, and do the labeling before installing the switches, jacks, and display. Use dry trans- fer lettering with a light coat of clear enamel to prevent damage. The prototype has the labels of the digit drivers used on S6 for setting the display decimal point; instead, use the sample times shown in Fig. 2. Mount Tl, an- chor the PC boards, and check for wiring errors. Power-up, test, and calibration When you apply power, LED2 should glow. Press S4 (display test), and the display should show all 8s and decimal points, and LED1 should light. If not, disconnect the power and re- check the wiring. With S8 in the out position, IC1 is off; set R7 for maximum gain, and apply a sig- nal of known frequency no more than 5 volts in magnitude to Jl or Become an EKI Certified Electronics Technician with EKI's home-study program. FULL COLOR CATALOG Features: Low cost (only $39 per module) 32 modules Used in schools all over the world Fast delivery No contract to sign Go at your own pace Can be completed in less than 6 months CALL OR WRITE TODAY: \ 1-800-453-1708 1-714-833-8711 " I 663 I NOYES AVE I R V I N E C A l J 2 ' CIRCLE 19B ON FREE INFORMATION CARD 37 TABLE 1— IDEAL FREQUENCY COUNTER DISPLAY RANGES FOR ALL S6/S7 SETTINGS Frequency Divider Setting (S7) Sample Time Setting (S6), s 1 2 4 6 8 0.01 1-99,9999.999 2-199,999,998 4-399,999,996 6-599,999,994 8-799.999,992 0.1 0,1-9.999,999.9 0.2-19,999,999.8 0.4-39,999.999.6 0.6-59,999,999.4 0.8-79,999,999.2 1.0 0.01-999.999.99 0.02-1.999,999.98 0.04-3.999,999.96 0.06-5.999,999.94 0.08-7.999,999.92 10.0 0.001-99.999.999 0,002-199,999,998 0.004-399,999.996 0.006-599,999.994 0.008-799,999.992 Frequency Divider Setting (S7) Sample Time Setting (S6), s 10 12 14 16 18 0,01 10-999,999.990 12-1,199,999,988 14-399,999,986 16-1,599,999,984 18-1.799.999,982 0,1 1 .0-99,999,999.0 1.2-119.999,998.8 1.4-139,999,998.6 1.6-159,999,998,4 1.8-179,999,998.2 1.0 0.10-9.999,999.90 0.12-11.999,999.88 0.14-13,999,999.86 0.16-15,999,999.84 0.18-17.999,999,82 10.0 0.010-999,999.990 0.012-1,199,999.988 0.014-1.399,999.986 0.016-1.599.999.984 0.018-1.799,999.982 Note: The actual frequency response is limited to approximately 1.8 GHz for all S6/S7 settings; all values shown here in kHz. DSP1 DSP2 DSPS DSP4 en o z o cc § uu _i o Q < cr FIG. 8— A CLOSEUP OF THE FOIL SIDE OF THE LED-display PC board. Most jumpers go directly to the foil-side pads; there are no separate holes. Since holes were drilled for J1-J3, there wasn't room for S8, so a notch was cut in the lower left corner. The wires to LED1 (beneath the PC board) are at upper right, black to anode, white to cathode. The pads between the displays are unused, where they fit against one another on the compo- nent side. J2 from a digital pulse generator. Tune C3 until the display- shows the same frequency as your standard, and the counter is calibrated. Switch S6 controls the number of digits of resolu- tion following the decimal point. The frequency is in kHz, so 1 kHz on the 10-second setting of S6 should show up as 1.000. As you increase the sample time on S6, the accuracy increases but so does the measurement interval. On the 0.1-second setting, the reading is to one decimal place but takes only 0.1 second, where- as on 10.0-second setting, there should be three decimal places, but the sample time also in- creases accordingly. The setting on S7 is the factor an input frequency is divided by. Thus, a 100-MHz signal reads 50 MHz on setting S7 to 2, 25 MHz OUTPUT (1.44Hz -7.21MHz) i + 5V- * GN0 TRIG OUT DISC IC5 555 THR ^^1MEC 7 RST BYP R9 MEG RIO M 1.7 100pF-1nF I C8 0.1 FIG. 9— AN OPTIONAL 555-TIMER ASTA- BLE square-wave generator for debug- ging the frequency counter. Both R9 and C7 are variable, to vary the output fre- quency from 1.44 Hz-7.21 MHz. The bread- board with this circuit on it appears in the lead photo. on setting S7 to 4, etc. Converse- ly, 100 MHz on the display on set- ting S7 to 10 implies a 1-GHz input. S5 resets the display to zero. SI retains a readout as long as needed, S3 just blanks the dis- play, S2 introduces clocking from an external source on J3, and LED1 indicates overflow. A simple astable multivibrator square-wave generator is shown in Fig. 9 for calibrating die frequency counter. Adjusting R9 and C7 will vary the output frequency from 1.44 Hz-7.21 MHz. R-E 38 2600 Super Sensitive RF Frequency Finder, $325. 3000 ^Top of the Line Universal Handi-Counter™, rd^. $375. 2210A Full Range Pocket Size LED. $239. Bench Portable (Fits in an attache case) with ALL the Handl-Counter™ Features plus More. $579. OFF THE BENCH AND RUNNING When OPTOELECTRONICS took fre- quency counters off the bench we created a whole new dimension - Frequency Finding . OurHandi-Counters 1 * 1 make Frequency Finding a reality by allowing you to pick-up radio transmitters at the maximum possible distance. Monitoring Enthusiast, Security Specialists, Broadcast and Design Engineers, Two Way and Amateur Radio Operators and Service Techni- cians have all made the move. Shouldn't you? 1300H/A Low Cost Ultra Sensitive (HF, UHF,VHF). $179. Model Range Low High Display B Digit LED Display W Digit LCD Signal Strength Sargtaph Universal Counter TCXO Option S030 10Hz 2.4SH: • • • ± lppm add St25. 3000 10HJ 2.4QHZ • • • ± 2ppm add S SO. 2600 1MHz 2.4GHz • e • i 2ppm add S SO. I300H/A 10Hz 2.4GHz ± .5ppm odd $ 75. 1MHz UGHz i .5ppm add S 75. Sensitivity' <1 to «10mV typical. NICads S; AC Charger/Adapter included. Carry Cose. Antennas and Probes extra. One year parts & labor warranty on all products. Toll Free Order Line: 1-800-327-5912 In Florida call (305)771-2050 FAX (305)771-2052 5621 NE 14th Avenue • Ft. Lauderdale. PL 33334 Visa. MC. COD, Cosh, M.O. accepted. Personal Check allow 3 weeks. 5% Shipping. Handling, {Maximum S10) U.S. & Canada. 15% outside continental U.S.A. CIRCLE 186 ON FREE INFORMATION CARD CHRISTMAS CARD r/f/s electronic Christmas tree is sure to make anyone's Christmas a little brighter. RON HOLZWARTH HERE'S A PROJECT THAT YOU'LL BE happy to display in your front window this Christmas season- it also makes a great gift that any- one else would love to display in his or her window. The electronic Christmas tree is actually made from a printed circuit board with traces that form the branches of the tree. Different colored LED's mounted on the board simulate Christmas-tree lights. A built-in microphone picks up any audio signals — such as Christmas mu- sic—and different strings of LED's light according to the spec tral distribution of the audio within a frequency band selected by the constructor. When in- stalled in the custom metal frame, all of the electronics and the batteries are hidden behind the black mat and protected by the front glass. The end result is an attractive little Christmas tree whose lights will blink in unison with any kind of audio. The photographs cannot con- vey the effect of the flashing lights, nor the vivid impression of seeing sound. Music becomes a quickly moving pattern of danc- ing lights. In fact, any sound be- comes an Interesting display as the microphone, which tops the tree, picks up any sound in the room. For the hearing-impaired, l it opens up a new window to sound. The project is also good for those who wish to learn about audio. For example, the tuning fork option only receives frequen- cies very near A440. Bui. it is hard to vocalize anything at any pitch without generating a dis- play. In fact, singing notes far lower than A440 generates vari- ous displays. In addition, inflec- tions, such as the rise in pitch that usually accompanies the conclusion or a question, are quite visible. The unit is powered from four AA batteries, although an AC adapter jack Is also included so that battery power can be con- served. It is a good idea to use an AC adapter whenever possible, as battery life is limited to about eight hours, depending on the volume level of the audio signal (more or less LED's will light), and the options selected. The strings of LED's can be more accurately thought of as bar graphs. The device includes an amplitude-discrimination cir- cuit that selects the harmonics of greatest amplitude and displays those harmonics in bar mode, at which time all others are in dot mode. An interesting experiment would be to interface the board with other circuitry. The outputs of the drivers are TTL- and CMOS-compatible. Since most LED posts can be wire-wrapped. wiring selected outputs to an in- put port is easy. The device can then function as a front end to allow your computer to monitor sound waves without (he com- plexity of digital filtering. The outputs can also be used to oper- ate relays, allowing lights of any power level to be used. Circuit operation Although the circuit may at first seem complicated, it really isn't. Figure 1 shows a block di- agram of the circuit. Signals from the microphone are ampli- fied, filtered, and automatically adjusted for gain in the automat- ic gain control (AGO section. The sections that follow are dupli- cated four t imes. All four sections are identical except for the fre- quencies that they handle. Each section has a level-adjust potenti- ometer, a bandpass filter, level shifter, demodulator and discriminator, and a display driver. Each dis- play driver drives a separate LED bar graph at the output. Three of the bar .-" graphs (A-C) con- tain ten individ- ual LED's. and one of them (D) contains twenty. Let's take a look at the schematic in Fig. 2, Power for the unit is supplied by the 4 AA batteries mounted on the board or supplied through the power jack ( J 1 ) on the back of the board. Since a bridge rectifier (consisting of diodes D1-D4) is used, DC of either polarity can be used, as well as AC. The batteries are disconnected whenever a plug is in the power jack. Two large electrolytic capaci- tors, C19 and C20. damp any transients caused by power sur- ges when a large number of LED's are lit. A voltage divider is formed by IC14, an LM336-2.5. which operates much like a Zener di- ode, but without nearly as much variation in reference voltage. The device has three terminals, and physically looks like a tran- sistor. However, the third termi- nal is not needed in this application, so the device is drawn in the schematic as a Zener diode. The reference volt- age from 1C14 is divided and then wired to op-amp ICl-c which is in a buffer configuration. The out- put of ICl-c (pin 8) then serves as an analog ground for later portions of the circuit. The output from the electret microphone (MIC1) appears as an AC waveform. It is amplified by ICl-b, which is configured as a non-inverting amplifier with an adjustable gain set by potentiom- eter R8. The next stage is a bandpass filter UCl-a), which selects the frequencies to be used by later portions of the circuit. Following the initial filter is Ihe AGC thai limits the signal when the output reaches approximately 1.1 volts peak-to-peak. The gain will in- crease slowly during periods of silence, reaching maximum sen- sitivity after approximately Ihree •**. seconds. The AGC section consists of op-amp ICl-d configured as a non-inverting amplifier. When the output of ICl-d Increases. Q2 turns on and allows a small amount of current to flow into C4. That will raise the gate volt- age of Ql, effectively lowering the resistance of R12, thus decreas- ing the gain of the amplifier as a whole. In the rest of the discus- sion, only one filter (filter A which controls bargraph A) will be de- scribed, as the others are identi- cal except for a few resistor values. A level-adjust potentiometer (R17) is next, followed by a buffer (IC2-a). As the potentiometer set- ting is increased, the amplitude of the filter output increases, causing more LED's to light at t he output. The stage that follows is nothing more than a summing amplifier. The input signal is summed with a portion of the output from the filter that fol- lows. With a little positive feed- back from the filter output, the Q is increased. Within the feedback network is another filter which has a resistive divider attached to it that causes it to act as a unity- gain filter. The next section is the level shift, which is necessary since the output of the filter appears as an oscillation about the analog ground. The display drivers re- quire an input measured from true ground, hence the level shift section is needed to amplify the g z o cr h- o LU 9 D < cc output as well as lower the wave- form so that it is relative to ground. The output of the level-shift section, which is a series of half sine waves, goes through D7 to a resistor and capacitor in parallel (R61 and C14). Note that this is similar to a conventional AM de- modulator. The resistor values control the rate at which the dis- play falls back to a zero state. In- creasing the resistor values will make the display fall back (turn off) at a slower rate. The output of the demodulator goes to the amplitude discrimi- nator, which is an op-amp config- ured as a comparator. Ger- manium diode Dll will conduct whenever one of the filter outputs reaches 0.2 volts. Thus, C 18 will charge and remain at 0.2 volts below the highest DC level. That causes the comparator for the fil- ter output of the highest DC level to switch its output to a high state. That output connects to the control input of one section of a 4066 bilateral switch which connects power to pin 9 of the corresponding LED driver put- ting it in bar mode. Resistor R65 is of a much larger value than R61-R64. Thus, when the filter output be- gins to decrease, the driver re- turns to dot mode and does not go back to bar mode until the out- put increases. The time constant is set so that the voltage lias sig- nificantly decreased in about one second, so the rhythm of the mu- sic is displayed as the LED's shift to bar mode at each beat. Varying the RC time constant will make the device operate differently. Bargraph D is driven by two drivers (IC12 and IC13) stacked end-to-end. They are made to function exactly as the others as far as the dot-to-bar mode transi- tion is concerned. The display drivers (IC9-IC13) control the lighting of the LED's according to the input voltage. A databook should be consulted if you wish to know more about the opera- tion of the display drivers. Filters and Q The Q of a filter defines how narrow the passband is. It is equal to the center frequency di- vided by the difference in fre- quency between the -3-dB points. The -3-dB frequency is LEVEL ADJUST AND BUFFERS AM BANDMSS LEVEL DEMODULATION DISPLAY FILTERS SHIFT AND DRIVERS DISCRIMINATION LED BAR- GRAPHS J—] AGC INITIAL BANDPASS FILTER MIC CtV H^ -Wr- ■w ^ HC8rr4 ,^iW- -VA- ■'■'.■»■ .--■:-:• ■ •>.-■.-. J .- vT"" 1 ^" " ."' -Wf +\ -Wr A FIG. 1— BLOCK DIAGRAM OF THE CIRCUIT. Signals from the microphone are amplified, filtered, and automatically adjusted lor gain. the frequency at which the peak- to-peak voltage is attenuated by one half from that at the center frequency, assuming a constant voltage at the input. Assuming we want a center fre- quency of 440 Hz, which Is the American tuning standard for musical instruments, and we want A fiat (415.3 Hz), one half step down, to be a — 3-dB fre- quency, and A sharp (466.16 Hz), for the other -3-dB point, 440/ (466.16 -415.3) = 8.65. That would be the Q required for an attenua- tion of one half when stepping up or down one key on a piano. Interestingly enough, the same Q is required to accomplish that across the entire keyboard. This is a necessary consequence of our tuning scale, which is now defined as the twelfth root of two multiplied repeatedly at each step. A logarithmic scale was thus developed by musicians centuries before mathematicians had opened their eyes, so to speak— 17 /is has been used for the approximation of this factor, which results in an error of less than one percent. It has been used for the construction of guitars and similar stringed in- struments for over three hun- dred years. The Delyiannis-Friend band- pass filter (the type used in this project) was first described by T. Delyiannis in 1968. It has a number of advantages over some other filters, such as reduced sensitivity to component toler- ances, minimal parts count, and a relatively easy-to-understand design algorithm. It has been de- scribed as a bridged-T RC circuit with an op-amp to provide nega- tive feedback. There are only two parameters needed to design a bandpass fil- ter. They are the center frequency desired for the passband. and the Q, or quality factor. The band- pass filter in its simplest config- uration is shown in Fig. 3. That filter has a bandpass center fre- quency of 1/2ji Hz. The first step in designing is to assign numer- ical values — that is, substitute the Q required. Assuming a Q of 4, 1/2Q = 0.125. and 4Q S = 64. After assigning numerical val- ues for each of the components, the filter is scaled up in frequency by dividing the capacitor values 42 INItttL IMttOfftSS flow FIG. 2— CHRISTMAS TREE SCHEMATIC, Power for the unit is supplied by the 4 AA batteries or via the power jack on the back of the unit. by the difference in frequency re- quired. Assume the frequency re- quired is 440 Hz. The difference in frequency required is equal to: /HEwtfoLD = 440/ ( 1/2jt ' = 880jl The capacitor value (0.125 F] is then divided by this number, giv- ing 4.52 x 10 ~ 5 , the new capaci- tor value for our filter. The next step, scaling to real- istic values, is best described by an analogy. In an RC network, the £ time constant remains un- 2 changed if the capacitor value is cd divided by any constant, just as 3 long as the resistor values are £ multiplied by the same constant, o 43 PARTS LIST All resistors are Vi-watt, 5%, un- Bargraph1-Bargraph4 — 50 LED's, less otherwise indicated. assorted colors (3 groups of 10, 1 R1— 10 ohms group of 20 — see text) R2, R7— 470 ohms Other components R3, R4,R6, R12, R53-R60. R66— MIC1 — 1-volt PC-mount electret mi- 100,000 ohms crophone R5, R74— 2200 ohms J1 — coaxial barrel-type power jack R8, R17-R20— 100,000 ohms, (Shogyo SJ-0202) multiturn potentiometer S1— C&K 7000-series right-angle R9, R10, R29-R44 — option depen- SPOT switch dent, see text and Table 1 B1-B4 — AA battery R11, R14, R15, R21-R28, R76— Miscellaneous: PC board, two bat- 10,000 ohms tery holders (Keystone 2223), met- R13, R45-R52— 1000 ohms al frame and cover glass, six %- R16, R65— 1 megohm inch spacers, solder, a bit of Christ- R61-R63^7,000 ohms mas spirit, etc. R64— 75,000 ohms Note: The following is available R67— 15,000 ohms from ART WORKS, Box 753, St. R68-R73— 2400 ohms Francis, Kansas 67756: PC R75— 5100 ohms board, $35 each (three or more, Capacitors $30 each); Partial kit, including C1-C3, C6-C13— 0.022 |xF, PC board, all components in- 5% metal film cluding S1, J1, battery holders, C4, C21-C29— 2.2 u.F, and all 1% resistors listed (does tantalum not include LED's, frame, or C5, C14-C18— 10 (iF, spacers), $90 each (three or tantalum more, $80 each); Complete kit, C19, C20— 1000 p.F, electrolytic Semiconductors IC1-IC6— LM324 quad op-amp including all of the above, plus 50 LED's in four colors, spacers, flat-black metal frame, front IC7, JC8— CD4066 quad bilateral glass and mat, $125 each (three switch or more, $100 each). All prices IC9-IC13— LM3914 bar/dot LED driver include shipping and handling. Check or money order only. IC14— LM336Z-2.5-voft reference Please order early — we will do Q1— 2N4393 or 2N3972 MOSFET our best, but cannot guarantee Q2— 2N3906 PNP transistor delivery in less than 30 days. D1-D6— 1N4002 rectifier diode When making technical inquir- D7-D14 — 1N34 germanium diode ies please include a SASE. UJ I LU G < The same concept happens to be true in an op-amp filter. That is, the center frequency (and Q) will be unchanged when this step is taken. A capacitor value of 0.022 u,F results in realistic component values across the entire audio band, provided the Q is not too high. So, since the capacitor val- ues will all be 0.022 \xF, we can divide 4.52 x 10 ~ 5 by 0.022x10 ~ e . resulting in 2,055. Both of the resistor values in Fig. 3 are then multiplied by that constant, resulting in 2,055 and 131,533 kilohms. At this point, it is a good idea to check your work. The values just obtained should be substituted into the following equation: J = 1/2jiCvHTR2 = l/2jr(0.022xl0 _6 x Vli.UbbKxl31.b33K) The result should be the origi- nal frequency. That equation can also be used to check the vari- ance in center frequency when standard component values are substituted, or to analyze an al- ready existing filter. In designing a unity-gain filter. a voltage divider must be added to the input, as shown in Fig. 4. Since the new Rl is one half of R2, that value is easy to calculate. For the new R3. the factor 2Q 2 /2Q 2 -1= 2(16V2(16)- 1 = 1.032 is then multiplied by the old Rl, resulting in 2121.5. To raise, or enhance the Q, positive feedback is added to the filter input, as in Fig. 5. The val- ues for Rl . R2, and R3 of Fig. 5 do not need to have the same scale factor as used before. A fine value for Rl and R2 is 10K: R3 will then be 10K(Q NEW /Q NEW -Q) or, for our example. _, ' "Vso Rl K 1 PUT 1 VM O— Wr^-jf-n :R2 =4Q ! IS OUTPUT \? FIG. 3— A BANDPASS FILTER in its sim- plest configuration. It has a bandpass center frequency of 1/Sbi Hz. C1 V» R1 INPUT 2Q2 c— w^H R3= _2QZ_ 20M FIG. 4— WHEN DESIGNING a unity-gain filter, a voltage divider must be added to the input. FIG. 5— TO RAISE THE Q, positive feed- back is added to the filter input. 10K(Q NEW /Q NEW -4) where Q NEW is the desired Q of the complete filter. The last step is to determine the closest stan- dard value for each resistor. There are four versions of the unit that can be built without having to make any calculations. The four versions are the broad- band option, the lower-four- guitar-strings option, the upper- four-guitar-strings option, and the tuning fork option. The tun- ing fork option is a good general- purpose version that will provide a nice display with most audio inputs. To use any of those options, you must refer to Table 1 : it shows the resistor values you'll need to use for the four filters to achieve the specified frequencies. Also, depending on which option you choose, the initial bandpass filter must be set up accordingly. lb use Table 1, first refer to the top section to determine the re- sistor values for the initial band- pass filter, the other four band- pass frequencies, and any special provisions for the particular op- tion. Then, from the bottom sec- tion, determine the resistor values for the other four filters according to the frequencies listed in the top section. The re- sistor numbers shown (R29, R33, and R37) are for filter A. For filter B, add 1 to the resistor number (for example, R29 be- comes R30, etc.). For filter C, add 2 to the resistor number, and for filter D. add 3. Although you can assign any of the four frequencies to any of the four filters, the display will be most interesting if you use the lowest frequency for filter A, next highest for B, and so on. Note that where it says to delete a com- ponent, you should leave it out but DO NOT jumper the pads on the board. Where it says to jumper a component, you should leave it out and solder a jumper between the pads. Construction If you like, you can etch your own PC board since the foil pat- terns for the double-sided board are provided. However, an etched, drilled, plated-through, and silkscreened board is avail- able from the source mentioned in the parts list. Keep in mind that the cosmetic effect of the green mask, silver branches, and white snow will be lost if you make your own board. Locating the components for installation is also easier using the pre-made silkscreened board. Complete and partial kits for the Christ- mas tree are also available. Before beginning construc- tion, you have to decide on how you want your LED's arranged. The authors intention was to make each detected harmonic a separate color. However, you are free to arrange the LED's in any pattern you choose, and you can also use whatever colors you like. In any case, the silk screening on the pre-made board indicates which bar graph each light be- longs to; there are short white lines between the LED leads. The lines going up (from left to right) are for bargraph A, the horizon- tal lines are for bargraph B. and the ones going down (from left to right) are for bargraph C. Bar- TABLE 1 Lower Four Guitar Strings Option: (E3, A3, D4, G4) Initial Filter Q = 1 .5 Center Frequency = 270 Hz R9 = 9.1 K R10 = 82K R41-R44 = 11K Upper Four Guitar Strings Option: (D4, G4, B4, E5) Initial Filter Q = 1.5 Center Frequency = 470 Hz R9 = 5.1 K R10 - 47K R41-R44 = 11K Tuning Fork Option: (A4 flat, A4, A4 sharp, B4) Initial Filter Q = 5.8 Center Frequency = 470 Hz R9 = 1.3K R10 = 180K R41-R44 = 12K Broadband Option: (E2, A3, B4, F6 sharp) (Jumper C2, delete C3) R9 = 1K R10 = 100K Note (frequency) R29 E3 (164.81 Hz) 174K A3 (220 Hz) 133K D4 (293 66 Hz) 97 6K G4 (392 Hz) 73.2K A4 flat (415.3 Hz) 69. 8K A4 (440 Hz) 66.5K A4 sharp (466.16 Hz) 61 .9K B4 (493.88 Hz) 59K E5 (659.26 Hz) 44.2K E2 (82 Hz) 11K A3 (220 Hz) 4.22K B4 (493.88 Hz) 1.8K F6 sharp (1480 Hz) 620 ohms delete F R41-R44 R33 R37 5.62K 348K 4.22K 261 K 3 16K 196K 2.37K 147K 2.26K 140K 2.10K 130K 2K 124K 1.91K 118K 1.40K 88.7K delete 680K delete 261 K delete 118K delete 39K NOTE: All versions except the broadband option require 1% resistors. y> ■ • • „ift 9 9 _* r* O O 9 (JM I €% \*f*\* < M H M i 1 1 1 1 1*!! 1 1 1 I M I * M 1 1 1 * M I M 1 1 1 1 I M M jT\^t I * I J * t \* 8 INCHES COMPONENT SIDE of the Christmas tree at half the actual size. o m O m 03 m x s 45 CO o z o cc i- o 2 Q < m m pi w RJ7 R18 . R19 R20 C22 C22 IC2 ■f ! J SC)\ r lRt2t ' VJr? R14 R15 .+ IC14 i IT , f .l ;■ ! i® . i ~|4 = 5(VB> ($) D (D 1 1) ;®^(D, . R58 R46 R55 n LRSl tItitiiI I 1 ) ICS [ 1 | R57 I R45 I R56 I 1 -watt R66— 82.000 ohms, 1% R69— 33,000 ohms R72— 220 ohms R73— 10 ohms Capacitors C2, C3, C16, C17, C19. C20, C23, C25, C28-C31, C39, C47, C56— 0.02 (j,R 20 volts, ceramic disc C4, C10, C21, C52— 22 fiF, 16 volts, radial electrolytic C5, C15, C22. C24, C26, C33, C49, C50, C51, C54, C55, C57— 0.1 |aF, 20 volts, ceramic disc C6-C9— not used C11— 0.33 p.F, 250 volts, poly- propylene C12— 0.47 \lF, 250 volts, poly- propylene C13— 10 m-F. 50 volts, axial elec- trolytic C14— 2200 fxF, 25 volts, radial elec- trolytic C18— 100 ^lF, 10 volts, radial elec- trolytic C27— 4,7 u,F, 10 volts, axial elec- trolytic, non-polarized C1 , C32, C34, C35. C40, C48, C58— 10 (xF, 10 volts, radial electrolytic C36— 0.039 m-F, 20 volts, ceramic disc C37— 0.01 |xR 20 volts, ceramic disc C38, C53— 0.05 |xF, 20 volts, ce- ramic disc C41, C45—470 ^F. 10 volts, radial electrolytic C42, C46— 0.22 |aF, 50 volts, poly- ester C43— 1 jxF, 35 volts, tantalum C44 — 4700 iaF, 16 volts, radial elec- trolytic swers a processed call. It is done so that the screen modes cannot be changed be the caller during Semiconductors IC1— LM1458 dual op-amp IC2. IC25— LM741 op-amp IC3— MC4001 quad NOR gate IC4, IC12-IC14, IC22— MC4081 quad AND gate IC5— SSi 202 DTMF receiver (Sil- icon Systems, Inc.) IC6— MC4028 BCD-to-decimal con- verter IC7— TCM1520 ring detector (Texas Instruments) IC8, IC21— 4N33 Darlington opto- coupler IC9— MC4071 quad OR gate IC10, IC28— MCT-2 transistor opto- coupler IC11. IC20, IC24, IC27— MC4011 quad NAND gate IC18— MC4013 dual D-type flip-flop IC15-IC17, IC23— MC4017 decade counter IC19— MC7805 5-voit regulator IC26— LM383 7- watt power amplifier D1, D2, D35, D40— 5.1-volt Zener di- ode D3-D10, D12-D18, D20-D32 D36-D39, D41—1N914 diode D11, D19 D33. D34— not used Q1-Q4— 2N4401 NPN transistor BR1— 50-PIV1.5-amp bridge rectifier BR2, BR3— 100-PIV 0.5-amp bridge rectifier Other components T1— 120712VAC 950 milliamp 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 a 70-volt line trans- former) XTAL1— 3.58-MHz colorburst crystal S1, S2— SPST momentary pushbut- ton 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-volt, 290-ohm coil (between 260-400 ohms) CALL ROUTING ADAPTER PARTS All resistors are Vi-watt, 5%, un- less otherwise noted. R101— 150 ohms, Vi-watt R102, R1 03— 10,000 ohms R104 — 330 ohms R1 05— 1000 ohms Semiconductors D101-D106— 1N914 diode Q101, Q102— 2N4401 NPN transistor Other components RY101, RY102— SPDT miniature re- lay, 12-volt, 320-ohm (nominal) coil S101, S1 02— SPDT miniature switch (or use single DPDT center-off switch) the seven-second "window" when an off-hook is raised at the Call- Screen/CRA output. If call rout- C0PYRIGHT /1TN I 1968 J.G.Koller HH A| ,,[f a- & 7"fc re - "75" ©: STt •ST! •SI 7i cs 1188- P • COMPONENT SIDE of the front-panel PC board, at full size. ing is desired for telephones only, then the remote screen selection feature should remain available all the time. That is achieved by leaving out the jumper wire from the CRA terminal E to the main- board TPV. When the two boards are 54 COMPONENT SIDE of the main circuit board, shown here at half of its actual size. ■ ■•hi •iiiiiiij m m <1 tVJtK f 2Hr . . [VJj_jj.d.. LL^ -8 INCHES - SOLDER SIDE of the main circuit board, shown here at half of its actual size. FIG. 5— THE SIX DIP SWITCHES and the two screen-status indicators (LED1 and LED2) must be mounted on the solder side of the front-panel board so that they can protrude through the cutouts on the cabinet. ORDERING INFORMATION Note: This information supersedes that presented last month. The follow- ing is available from Electronic Control Systems, R.D. 2 Box 3308, wer- nersville, PA 19565: A set of two dou- ble-sided, plated-through PC boards for S39.95 (add $2.00 postage and han- dling); a complete kit including PC boards and all parts except the cabinet for $139.00 (add $3.50 postage and handling). Pennsylvania residents add 6% sales tax to all orders; check or money order only. finished they are connected to- gether and mounted at a right angle to each other in the cab- inet. But remember to inspect all wiring and solder joints for poor or non-existent connections be- fore doing so. All interconnec- tions between the two boards should be made with fine gauge hook-up wire (AWG 30) to reduce mechanical stress on the boards during assembly. The boards may be installed in any type of cabinet the builder wishes. If the LED indicators are panel mounted and the code-select DIP switches are replaced with hard wire jumpers, then the front- panel board can be mounted any- where inside the cabinet. The two power ICs (IC19 and IC26) must be heat sinked. Their location on the PC board allows them to be bolted directly to the cabinet wall using 6-32 hard- ware. (Make sure that the nuts used are not so large that the IC cases crack when tightened against the tabs). Both IC heat- sink tabs are at ground potential so they do not require insulating. If a plastic cabinet is used, a strip of aluminum sheet metal may be mounted to the tabs as a heat sink. The majority of heat gener- ated occurs when the screener is ringing telephones, so large sinks are not needed. A l-x5- inch strip of aluminum should be sufficient. Power-up Set the ring-voltage potentiom- eter (R51) to an initial 10-O'Clock position. If possible, adjust the ring voltage to 90 volts using a DMM and an REN load of 1.0. If the CRA is used, make sure it is switched off. Connect the Call- Screen to a phone line. Lift the receiver and check for a dial tone. Connect an ohmmeter across 55 Put Professional Knowledge and a COLLEGE DEGREE in your Technical Career through HOME ™ STUDY -^ a o o UJ o Q < EC 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 250 Frontage Road Slidell, LA 70460 the + 5-volt supply line and make sure that no low resistances exist (less than IK). Similarly, check the + 16-volt supply line for any resistance under 15K. Connect a DC voltmeter across the 5-volt supply, power up the unit, and check for the proper voltage. AJso check the 16-volt supply; under idle conditions it should read close to 18 volts. Lift the receiver of the tele- phone and check for screen mode changes using the "#" and '**" keys. Leave the screen mode in "Limited Screen" (one LED lit). Note that screen mode changes via a connected phone are al- lowed for only seven seconds fol- lowing an off-hook transition. Using two telephones connected to the CRA output jacks, have a caller enter each code, and also no code, with the CRA in each of its two modes. Verify that call routing occurs. In a similar manner, cause one phone to ring but answer the call through the non-ringing phone. Verify that the incoming call is properly answered. Repeat the step using the other telephone. Verify that outgoing calls can be Try the ClEEtrDtliES bulletin board system (RE-BBS) 516-293-2283 The more you use it the more useful it becomes. We support 300 and 1200 baud operation. Parameters: 8N1 (8 data bits, no parity, 1 stop bit) or 7E1 (7 data bits, even parity, 1 stop bit). Add yourself to our user files to increase your access. Communicate with other R-E readers. Leave your comments on R-E with the SYSDP. RE-BBS 516-293-2283 o e X o z o vn 6 8 Vt ooo e ooo o O i o o — [©Vf o-Oi e oo o oe I o •ooo~£J 77. 90 4/ Oh • SOLDER SIDE oi the front-panel PC board, at full size. made by either phone regardless of the CRA mode. Be sure to re- view last month's article for a dis- cussion of all screening features. The detailed circuit description should help you to troubleshoot any problems. Then you're ready to give out your access codes! R-E 56 SUSIE simplifies digital design, and makes breadboards a thing of the past TJ BYERS DESIGNING DIGITAL CIRCUITS MAY look like child's play, but the jour- ney from inspiration to a func- tional circuit is fraught with peril. Propagation delays, glit- ches, timing violations, and bus conflicts can turn a simple idea into a nightmare. The traditional method of test- ing a digital design is to bread- board the circuit, then drag out the logic probe, oscilloscope, and logic analyzer to find out why it doesn't work. The modern meth- od is to simulate the design on an IBM-compatible PC using a pro- gram called SUSIE (standard universal simulator for improved engineering), made by a compa- ny called Aldec. If you knew SUSIE SUSIE is a simulation program that graphically depicts the tim- ing and logic events of a digital circuit. Although SUSIE uses software to verify the design, the results are the same as if you had built the circuit and used an ul- tra-sophisticated logic analyzer to test and debug it. SUSIE simulates the operation of logic IC's using mathematical models stored in a library. IC models include algorithms for setup and hold time, pulse wid- th, edge-to-edge transfer delay, and other propagation param- eters. There are different libraries for different types of components, with one library for TTL devices, another for CMOS, yet another for ECL, and so on. SUSIE comes with those three libraries, plus two additional libraries con- taining switches and other pas- sive components. Aldec's Model Builder Compiler (MOBIC) allows you to model IC's that are not in- cluded in the libraries. You can also purchase extra libraries for devices including memory IC's, microprocessors, gallium-arse- nide {GaAs) logic, programmable logic devices (PLD's), and gate ar- rays, plus libraries for computer interfaces and industrial compo- nents like stepper- motor control- lers. The optional libraries cost between 6800 and $2,000. How- ever, you can do a lot with the nearly 6000 devices that come standard with the basic SUSIE package. o m O ~n to o 57 CO o o IT § O Q < EC PRODUCTS MENTIONED SUSIE Aldec Co. 3525 Old Conejo Rd. #111 Newbury Park. CA 91320 (805) 499-6867 OrCAD OrCAD Systems Corp. 1049 S.W. Baseline St. Suite 500 Htllsboro, OR 97123 (503) 640-9488 SuperCAD Mental Automation 5415 136th Place S.E. Bellevue, WA (206) 641-2141 A SUSIE example To understand how SUSIE works, let's take an example. The circuit shown in Fig. 1 is a divide- by- five counter with a 50% duty cycle. Ordinary divide-by-5 coun- ters produce an asymmetric out- put with a 20/80 timing ratio, but by using a negative edge-trig- gered flip-flop and half-state tim- ing, we can make a divide-by- five counter with a 50/50 timing ratio. Three counter stages are needed to divide by five, with one driven on the inverted clock to compensate for the odd number of states. That is, to achieve the sixth state needed to produce a 50% duty cycle, ICl-b must change state on the negative edge of the clock at r=2.5. and that can be forced by timely triggering of the flip-flop's preset input (pin 10). Debugging a circuit like that in hardware could get quite thorny. Let's see how SUSIE handles the situation. Design entry SUSIE's design verification process is divided into three steps: design entry, test vectors, and simulation. During design entry you load and define the sec- tion or sections of the circuit you want to display on the screen. SUSIE can show as much or as little of the design as you wish. You can zoom in on a single IC or display waveforms for every point in the circuit. Design entry begins with a netlist. The netlist contains a list of all the components in the cir- cuit and their connections to one IN1 o— J PR Q IC1-a Va74LS11Z CLK Ht K CLR T 6 8, ^^ IC3-c\ 10 • 74LSD2 A K CLR q IC1-b 1 ft74L511Z OK, ^D T 9 1 to 1 J PR D !C2-a 'ft74LS112 «3 OR° 15 V* 0UT1 1C3-BN. 4 I74 74LS02) FIG. 1— DIVIDE-BY-FIVE counter with a 50% duty cycle output. i Ul-2.... UI-5 i UMZ... i Ui-13... i Ul-IQ... — Stin.l — 4-Break. " i 520 ns Top line: U2-7 . . i U2-13. 1 UZ-11. i U2-12. 9^0000111111+80= 15ns "-> ■■ S initiate |Similate: que step=[Ll,t+h{Enter> fast=IR],{-J a«to=tL*BhtIns>; {F2>=nore-> -■ fia2.net g node: I j Scale: ions i i- i > i It m >■* i Prop; au.q FIG. 2— SUSIE SIMULATION of the divide-by-5 counter siiown in Fig. 1 another. SUSIE reads the netlist, downloads the specified compo- nents from their libraries, and "builds" the circuit in RAM. (See the sidebar, "Writing A SUSIE Netlist," for more information about netlists.) After SUSIE loads the netlist, you define which part(s) of the design you want to view by listing pin numbers or node names in the signal column on the left side of the display screen. For exam- ple, in Fig. 2, we defined several nodes (INI, OUT1) and various pins oflCl and IC2 for display Note that we selected no pins from IC3, and only some from IC1 and IC2. The reason is that too much information can be more confusing than not enough. The point is that, regardless which nodes are displayed, the entire circuit is tested during simula- tion, and all questionable timing events (glitches, etc.) are brought to your attention. Of course, after creating a de- sign, you can save it to disk and load it again later. 58 = Stin.l=;Bre«k HI ; i Jl-Z., a Ul-5.. i U1-1Z. i Ul-13. i Ul-10. i UZ-3., o 112-5.. b IIZ-6.. o U2-7. . i UZ-13. Si UZ-11. i UZ-L2. p+eooieoiiietB- p Sinulate ; Sinulate: one step^LLW, {Enter) fast=[R],{) auto=[l*Rl,{Ins); {F2}=more-> ' fig3.net m nuae: F Scale: 10ns i- -f m 1 1 li R Prop^_agg FIG. 3— DIVIDE-BY-THREE counter created by changing the test vector on pin 10 of IC1 to pull pin 12 high. The original circuit (Fig. 1) becomes a divide-by-3 counter with a 50% duty cycle. Signal -» Stin,4=lBreak i Ut-2., o Ui-5. . i Ui-iZ. i Ul-13. i Ul-10. o UZ-7.. i UZ-13. i UZ-11. i UZ-12. i<-Glitc)»-ri j Delete 3-*0001000010*-BO= 15ns "-4 - Sinulate Sinulate: one step=[Lh{+), (Enter) fast=[R],{) auto=H*Rl,{Ins}; {FZJ=more-> ; fig4.net node: 1 B Scale: ?ns :-> g I' . '! i Prop: Aug FIG. 4— SUSIE SIMULATION of the complete divide-by-3 counter. Test vectors For a design to function, it must have some kind of input; SUSIE's inputs come from test vectors. A test vector is nothing more than a waveform that, when applied to an input, causes something to happen in the cir- cuit. SUSIE can serve up an al- most limitless variety of test vectors. You create test vectors using ei- ther an ASCII text editor or SUS- IE'S built-in test-vector editor. Test vectors may be stored in ei- ther a compressed binary format or one of three ASCII formats. The ASCII versions differ both in the format of the file and in the way it is used. • The line version is formatted as a string of l's (high) and O's (low) that establishes the timing and shape of the waveform. Each line in the file represents one wave- form, and you may describe and load as many lines (waveforms) as you wish. • The bus file is similar to a line file, except that it is written in hexadecimal notation, and is used primarily to define wave- forms for an entire bus. • The waveform file consists of statements written in Aldec's pro- prietary high-level language, and it can be used to create wave- forms too complex for the other methods. To use SUSIE'S built-in editor, you simply place the cursor over the signal to be edited and man- ually key in the desired wave- form. After the test vector appears satisfactory, you can save it to a line or bus file directly from the screen. However, test vectors created on the screen using Aldec's programming lan- guage cannot be saved to a file; you can retain such files only by creating them first with a text ed- itor. After defining and naming a test vector, you can load it into any netlist design entry. Al- though a test-vector file may con- tain any number of waveforms, only one file may be loaded at a time. SUSIE also has an internal ten- stage binary counter that can be used along with a test-vector file OBTAINING SUSIE As digital circuit-simulation pro- grams go, SUSIE is a real bargain. But at $995 {optional libraries not in- cluded), it's too pricey for the average hobbyist. Fortunately, Aldec offers a free SUSIE demo disk that does every- thing the full-blown SUSIE package does, but on a smaller scale. Instead of 6000 devices, the demo contains 26 logic devices and seven PLD's, plus a full complement of switches and passive components. Although the demo disk can't simu- late every digital design situation, the logic types are varied enough that, with prudent part selection, you can test a wide variety of design types — for free. Table 1 lists the IC's sup- ported by the demo disk. The letters xx stand for any logic technology, ie. LS, AS, F, etc. IC models include set- up and hold time, pulse width, edge- to-edge and other propagation delay parameters. r-e o m o m m u to to o TABLE 1— DEMO DISK SUPPORTED COMPONENTS 74xx00 Quad 2-input NAND gate 74xxQ2 Quad 2-input NOR gate 74xx04 Hex inverter 74xx05 Hex inverter (OC) 74xx07 Hex buffer (OC) 74xx08 Quad 2-input AND gate 74xx10 Triple 3-input NAND gate 74xx1 1 Triple 3-input AND gate 74xx20 Dual 4-input NAND gate 74xx30 8-input NAND gate 74xx74 Dual D-type flip-flop 74xx85 4-bit magnitude comparator 74xx86 Quad 2-input XOR gate 74xx90 BCD decade counter 74XX138 3-of-8 decoder 74xx1 51 8-input multiplexer 74xx1 53 Dual 4-input multiplexer 74xx157 Quad 2/1 multiplexer 74xx161 Presettable binary counter 74xx175 Quad D-type flip-flop 74xx193 BCD up/down binary counter 74xx244 Octal driver Three-state 74xx245 Octal bus transceiver 74xx279 Quad S-R latch 74xx373 Octal transparent latch 74xx374 Octal D-type flip-flop three-state 10H8 PLD 16L8 PLD 16R4 PLD 20L8 PLD 20L10 PLD 22V10 PLD 32VX10 PLD .« 0UT1 8 T 1?l '■ ■ 3 J PR ICt-a V? 74LS112 CLK K OR Q '/4 74LS02)O- 13 COC K CLR q IC1-b V2 74LS112 J PR Q 1 9 e IN 1 2 r % 10 i 13 Vcc . 11 J K CLK PR o IC2-b 'ft74LS112 clr 7 5 \ £3 \ IC3^a\ 1 -p 1V.1 74LSD2>0 1 I C3-tf\ 4 6 1 L v, r c FIG. 5— FINAL SCHEMATIC of the divide-by-3 counter. w o z o EC L±J o 5 < as a square- wave signal gener- ator or as a frequency divider for other test vectors. Simulation Circuit simulation is the third and final step in the simulation process. It is where you get to see what happens in the circuit as a result of the applied inputs. Its also where you learn whether or not your design will fly. The simulation mode provides numerous features that simplify analysis. You can preset any de- sign element to an initial logic state, search for timing glitches, and set breakpoints for incre- mental timing measurements. Most simulations use the inter- nal binary counter for the signal source, as we did for our test de- sign in Fig. 1. The counter has ten stages (BO through B9), each of which is half the frequency of the preceding stage. The pulse width of BO is adjustable between 10 picoseconds and 999 seconds. For our simulation, we set BO at 15 ns and used Bl (30 ns) as the clock. The resulting display is shown in Fig. 2, which we will now use to verify our design. At power up (r = 0). the output of ICl-b (pin 9) is set high. On the first clock pulse, the input to pin 13 goes negative, causing the flip- flop to toggle and force pin 9 low and pin 7 high. That sets the stage for ICl-a to reset on the fall- ing edge of the same clock pulse, which in turn causes pin 12 to go low and prevents further clock pulses from affecting ICl-b. However, IC2-a continues to to- ggle, sending signals to IC2-b un- til its inputs reach a logical combination (pin 11 high, pin 12 low) that causes the inverted out- put (pin 7) to go low on the falling edge of the third clock pulse. That forces ICl-bs preset input (pin 10) low and output (pin 9) high. A half state later, ICl-bs new logic state forces IC2-b's pin 1 1 input low. That releases the hold on (Cl-b and enables the counter to function as a normal state machine until the forced state is reached again. The re- sulting waveform at OUT1 shows us that our design does indeed work as predicted. Using SUSIE to modify a design Unlike many analog and digital simulators, SUSIE doesn't need to compile the netlist before it can do a simulation, and that makes it possible to change test vectors and circuit connections without having to change the netlist. For example, let's say that we wanted to modify our design so that it was a divide-by-3 counter instead of a divide-by-5 counter. That is easily done using SUSIE's on-screen editing features. Looking at the timing screen in Fig. 2, we see that in order to pull 60 LISTING 1— NETLIST OF DIVIDE-BY-3 COUNTER sockets u1=74LS112 sockets u2 = 74LS11 2 sockets u3 = 74LS02 /in1,u1/1,u2/13, u3/8, u3/9 ;signal input /out}, u1/2, u1/9, u3/5 ;divide-by-3 out u1'3, ul/7 u1/6, u3/6 uL'10, u2!7 ;U1b preset U1/13. u3'10 u2/1 1 , u3/2, u3/3, u3/4 U2/12, U3/1 /GND, u1/8, u2/8, 03/7, U 1/11 A/CC. u1/16, u2'16, u3/14, u1/4, u1/15, ul/14, ut'12, u2/10. U2/14 WRITING A SUSIE NETLIST Like all circuit-simulation pro- grams, SUSIE uses a netfist to define the circuit. However, unlike many cir- cuit simulators, which require special tools to create the netfist, SUSIE'S netlist is in pure ASCII, which means all you need to make a SUSIE netlist is a text editor. The process begins with a sche- matic of the design . ( Refer to Fig . 1 in the text for this discussion.) First, the circuit's inputs, outputs, and compo- nents are identified by name and number. Those labels are then en- tered into the netlist using the format: sockets schematic label = device type. The order of the parts is really immaterial. Next, connections between de- vices are listed by component label and pin number, with a comma sepa- rating each entry. Again no special order is necessary, and comments (placed after a semicolon) can be in- serted in the netlist to help describe large designs. Signal inputs, outputs, and power-supply connections are preceded by a slash, A separate line is required for each node in the circuit (a node is any point where two or more pins or wires con- nect). However, if the number of con- nections to a node is greater than will fit on a line, the listing can extend to the next line by ending the first line with an "&" character. There is no limit to the number of lines you can use for a single node, provided the lines are in sequence and linked via the "&" character. That's all there is to it. The netlist shown in Listing 2 is ready for simula- tion. Several schematic-capture pro- grams, including OrCAD and Super- CAD, can generate a SUSIE netlist directly from a screen schematic. R-E LISTING 2— NETLIST OF DIVIDE-BY-5 COUNTER sockets U1-74LS112 sockets u2 = 74LA1 12 sockets u3 = 74LS02 /in1, u1/1, U2/13, u3/8, u3/9, u2/1 ,'out1, uV2, u1/9 u1/3, ut/7 u1/5, u2/3, U3/11 u1/6, u3/6 U1/10, u2/7 ul/12, U3/13 u1/13, U3/10 u2/5, u3/12 U2/6, U3/5 u2/1 1 , u3/2, u3/3, u3/4 U2/12, u3/1 /GND, u1/8. u2/8, u3/7, ul/11 A/CC, u1/16, U2'16, u3'14, u1/4, u1/15, u1/14, u2<4, u2/15, u2/2, u2'10, u2/14 ;signal input ;divide-by-5 out ;U1b preset this off we have to force the break at t= 1.5 instead of at r = 2.5. We can test our theory by applying a custom-made test vector to pin lOoflCl-b. The test vector can be created in several ways, but the best method for our situation is to use the Aldec programming lan- guage. First we look at the dis- play to determine where the changes must occur. For our ap- plication, the test vector must have eight high pulses followed by four low pulses. The Aldec equation for that waveform is (H8L4)100, where H8 specifies eight highs, L4 specifies four lows, and 100 indicates that the preceding pattern should be re- peated one hundred times. The repeat gives us plenty of time to play with the circuit before run- ning out of signal. To perform the modified sim- ulation, we load the original de- sign into SUSIE and apply the test vector to pin 10 of ICl-b (Fig. 3 ). Analysis of the timing display shows that pin 12 of ICl-b needs to be tied high so that ICI-b isn't affected by IC2-a. You could go into the netlist and change pin 12s connections, but SUSIE s ed- itor lets you assign IC pins or nodes to keyboard keys that manually override the design stimulus. In our case, we assign- ed the a key to pin 12, then tog- gled the input high for the simulation. The result of this simulation, shown in Fig. 3, shows that our assumptions were correct and that the new de- sign does work: For every three input pulses, the circuit pro- duces one output pulse, and the duty cycle is 50%. The netlist for that circuit is shown in Listing 1. The next step is to alter the cir- cuit so that it generates the test vector itself. This can also be done in SUSIE using connectivity markers — screen notations that tell SUSIE to make a connection between like mark- ers. As it turns out, the only change we have to make in the original design is move pin 5 of IC3 from IC2-a to pin 9 of ICl-b using the "aa" connectivity markers shown in Fig. 4. The ° rules for connectivity are: If you S mark an input for screen con- S nectivity, all previous connec- Eg tions to the input are severed; if _ you mark an output for screen g 61 Q Q < est possi- early does crude ap ird, and fi of service lise oppor p prototyp 3u can nov ok-on-De /ou shoulc ite virtually >, at pretty :peed — bu CO o z O a: t- o Q D way are easily created. While the UV photopolyrner nor- mally used is both expensive and hard to get, a possible hacker sub- stitute could be the Merigraph pho- topolyrner used for rubber stamps, and available by way of Gratham or R.A. Stewart. A second generation visible light photopolyrner is being developed at Dupont, and one major system which uses these is Quadrax. Advantages of the visible photopolyrner include its lower viscosity, the ability to use a cheaper laser, and (with proper safety precautions) being able to see what you are doing. 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De P t.KREi2 4100 N.Povrerline Rd., Suite K-4 Fompano Beach, FL 33073 1-800-445-9285 For Our Record I. the undersigned, do hereby declare under penalty of per- jury that all products purchased, now and in the future, wilt onjy be used on Cable TV systems with proper authorization from local officials or cable company officials in accordance with all applicable federal and state laws. FEDERAL AND VARIOUS STATE LAWS PROVIDE FOP. SUBSTANTIAL CRIMINAL AMD CIVIL PENALTIES FOR UNAUTHORIZED USE. Date: Sipled: No Florida Sales! CIRCLE 191 ON FREE INFORMATION CARD 4.7K 10uF right audio left audio a-WA-\{ video (A) 7511 right audio c— WW~jf loft audio video .o-^vW-jfr (B) right audio left audio video (C) o-wHf- (inputs) t12V CTRL1 CTRL2 (outputs) MUTE RG. 1— THIS TRIPLE AUDIOVISUAL SWITCHER uses the Hitachi HAA11508 to simulta- neously select video and two-channel stereo audio from any one of three sources and then route them to one of two selected outputs. Batelle, while conventions and semi- nars are sometimes done by the CAD/CIM Roundtable. One of the many sources for traditional CAD/ CAM support software appears to be Control Automation, One thing that's totally obvious to me is that the PostScript language will play a major role in the future of desktop prototyping. Obvious rea- sons here are PostScript's nearly total device independence, its in- credible graphical performance (es- pecially for three dimensions), and its ability to let your favorite el-cheapo word processor completely and total- ly blow away virtually any of today's costly CAD/CAM packages. For our contest this month, just add to our Santa Claus machine di- alog in some useful way. There will be all of the usual Incredible Secret Money Machine book prizes going to the dozen or so top entries, with an all-expense-paid (FOB Thatcher, AZ) tinaja quest for two going to the very best of all. As usual, please send your written entries to me here at Synergetics, instead of Radio- Electronics. An incredible data book Certainly one of the most beautiful, largest, and most impressive data books I've ever run across is the in- credible new ASSP for Audio and Video Applications data book offered by Hitachi. It is crammed to the rafters with unique new hacker inte- grated circuits. Picking a sample more or less at random, Fig. 1 shows an audiovisual switch using their new HA1 1 508 chip. This beast is hard to describe. It simultaneously switches one video and two stereo audio channels from your choice of three sources. As Fig. 2 shows, there are two separate tri- ple outputs, selected per the CTRL1 and CTRL2 lines. The audio on the second triple output can get muted using the mufe input. This dude is intended to select three audiovisual sources inside a TV set and route them to two possible destinations. But it cries out to be used as part of a home- or low-end- studio control center or a switching bay. The quality specs seem fairly im- pressive. While a 12-volt supply is CTRL1 CTP.L2 OUT I OUT II o o A A O 1 A C 1 1 B B 1 o B C FIG. 2— THE TRUTH TABLE for the triple audio switcher. Logic signals on the con- trol inputs decide which input gets se- lected. An optional mute input turns off the audio only on output II. recommended, anything from 8 to 13 volts can be used. All the inputs and outputs are supposed to be capaci- tor-coupled. Since the switching times and all the overlaps are not specified, this chip appears to be mainly intended for use in static switching or source selection. In- stead of being applied to chroma-key or picture-insertion applications. Nat- urally, for any higher-quality switch- ing, full double-sided PC boards with lots of ground plane are an absolute must. More on data compression There sure was plenty of ongoing hacker interest in all of that data-com- pression stuff we looked at a few months back and in the Hardware Hacker lire prints. Much of the action today centers on the new Discrete Cosine Transform, especially in high- resolution color computer and TV displays. Figure 3 is a bibliography of some of the heavier duty papers on the DCT. Start out with Chris Ciarcia's introductory tutorial in Circuit Cellar Ink, and then go on to the fancier stuff shown through Interlibrary Loan at your local library. To compress any video image, indi- vidual 8x8 pixel blocks have their discrete cosine transform taken, by using either hardware or software. The result of this transform is a list of frequencies and amplitudes. Any change so minor that the eye can't see it anyway gets replaced with a zero, leaving a sparse data set. Put another way, what you don't know Cor see) won't hurt you. The sparse data set then gets fur- ther compacted using Huffman or similar techniques. The net result is a video compression in the 30:1 range without causing significant visual degradation. The reasons for compression is to reduce your disk storage time and your communication time. Far more important, this sort of data compres- sion is essential to squash an HDTV image down into reasonable band- width channels. So knowing and un- derstanding video compression is an essential part of the new multimedia revolution which is combining video and computing. Two sources of DCT chips include C-Cube and SGS, while some useful (but very much slower) do-it-yourself software routines are shown in the Garcia article. Digital sine- wave generator Hardware hackers interested in communications are really getting off on a great new integrated circuit from A Fast Algorithm for the Discrete Cosine Transform C.H. Smith, IEEE Transactions on Communications Sept, 1987 pp 10O4-1G09 Image Compression for High Speed Network Transmission C. Ciracia, Circuit Cellar Ink, Aug/Sep 1990, pp 19-26 Teleconferencing K. Rao. Van Nostrand Retinoid Company, 1985. Digital Coding of Waveforms N. Jayant, Prentice Hall, 1984. A Hew Wave in Applied Mathematics B. Cipra, Science 24 Aug 1990. pp 858-859. Survey of Adaptive Image Coding Techniques A. Habbibi, IEEE Transactions on Communications. Nov 1977, pp 1275-1284. Advances in Picture Coding H. Mussmann, Proceedings ol the IEEE, April 1985, pp 523-548. Progressive Transmission of Gray-Scale and Binary Pictures K. Knowlonton, Proceedings ol the IEEE, July I960, pp 885-896. Predictive Coding Based on Efficient Motion Estimation R. Srinivasan, tEEECont. Communications, May 14 1984, pp 521-526. DCT Processing ol NTSC Composite Video Signals A. Ploysongsang, IEEE Trans, on Communications, March 1982, pp 462-479. FIG. 3— A FEW OF THE RECENT PAPERS on video-image compression and the DCT discrete cosine transform. Official 1934 SHORT WAVE RADIO MANUAL Build simple performance old lime shortwave radiosl All of the secrets are here: the circuit diagrams, parts layout, coil specifications, con- struction details, operation hints, and much more! This is a compilation of shortwave construction articles from "Short Wave Craft" magazines published in the 20's & 30's, It's wall-to-wall "how-to." Included are circuit diagrams, photo- graphs, and design secrets of all short- wave receivers being manufactured in 1934 including some of the most fa- mous: SW-3. the SW-5 "Thrill Box", the deForest KR- 1 , the Hammurland "Comet Pro", and many more. Also included is a new chapter show- ing how you can use transistors to re- place hard-to-find vacuum tubes. You'll even see the circuit that was lashed together on a table top one night using junk box parts, a hair curler and alliga- tor clips. Attached to an an- tenna strung across the base- ment ceiling and a 9 volt bat- tery, signals started popping in like crazy. In a couple of minutes an urgent message from a ship's captain off Se- attle over 1500 miles away was heard asking for a naviga- tor to help him through shallow waterl These small regenerative receivers are extremely simple, but do they ever perform! This is a must book for the experimenter, the survivallst who is concerned about basic communlcaUon. shortwave listeners, ham radio opera- tors who collect old receivers, and just about anyone interested in old-time radio. Great book! Fun to read! One of the best old-time radio books to turn up in years. Heavily illustrated! Order a copy todayl 8 1/2x11 paperback 260 pages only"$ 15.70 postpaid! r Lindsay Publications 1 Box 583-WA8 Manteno IL 60950 I I Send a copy of Short Wave £ ^Manual. Enclosed is $1! ■Radio 15.70. Chk, MC, Visa. Send a free cata- log of other books. 1 Nsrni- 1 1 1 ^Ity St Zip 1 -J 73 y z o F u UJ _i LU o Q 2 Micro Linear. This is their ML2035 Programmable Sine-wave Generator. Cleverly disguised as an eight-pin mini-DIP. this new chip is an $8, full performance, 16-bit digital sine-wave generator. It has a 21 -bit phase ac- cumulator and a 9-bit sine lookup ta- ble built into it! The device can easily produce any sine wave from 1 Hz to 25 kHz in 1 -Hz steps, and its serial interface mates beautifully with virtually any computer or microcontroller. Figure 4 shows the extremely simple circuit. A split sup- ply of +5 and -5 volts is needed. The output frequency resolution will be: f OUT = fxTAl7 8 ' 388 ' 608 Thus, you would use the 8.388608- MHz crystal to get a 1-Hz resolution. Or you could apply any external fre- quency up to 12 MHz. Your output sine-wave frequency is determined by the 16-bit digital word you last selected. For instance, a dig- ital "1" would get you 1 Hz, while a "5623" Cor a hex $15F7) will get you 5,623 kHz, Your output is a clean and low-distortion sine wave of around 1 2- volts peak-to-peak. In order to save on package pins, your digital control word is entered serially. There are three pins involved. The serial input data CSID) pin accepts one data bit at a time, the least signifi- cant bit first. The SCK or serial clock accepts each new data bit on its ris- ing edge. Finally, the LAT or laich pin stores the input serial data stream on its falling edge. This should interface beautifully with the game-paddle port of an Ap- ple lie, or anywhere else you have three I/O lines available from a com- puter or microcontroller. There's also an ML2036 in a larger package with some extra features at slightly higher cost. One obvious tip: You do enter the frequency in binary or in hex, and not in decimal! Don't laugh. That's a very common hacker mistake. As a second contest for this month, just tell me something dif- ferent you would do with this new ultra-cheap, ultra-simple, and ultra- precise digital sine-wave generator. New tech literature Schaevitz has a free Handbook of Measurement and Control that gives the fundamentals of LVDT position- ing sensors. From SGS, there's a SANTA CLAUS MACHINE RESOURCES Batelle 505 King Avenue Columbus, OH 43201 (614) 424-7782 CIRCLE 319 ON FREE INFORMATION CARD CAD/COM Roundtable 1050 Commonwealth Avenue Boston, MA 02215 (617) 232-8080 CIRCLE 320 ON FREE INFORMATION CARD Control Automation 2350 Commerce Park Dr NE, #4 Palm Bay, FL 32905 (407) 676-3222 CIRCLE 321 ON FREE INFORMATION CARD DTM 1611 Headway Circle B2 Austin, TX 78754 (512) 339-2922 CIRCLE 322 ON FREE INFORMATION CARD DuPont 1007 Market Street Wilmington, DE 19898 (302) 774-1000 CIRCLE 323 ON FREE INFORMATION CARD Freeman Supply 1246 West 70th Street Cleveland, OH 44102 (800) 321-8511 CIRCLE 324 ON FREE INFORMATION CARD Grantham/Polly-Stamp 418 Central Avenue NE East Grand Forks, Ml 56721 (218) 773-0331 CIRCLE 325 ON FREE INFORMATION CARD Industrial Education 1895 Crooks Road S135 Troy, Ml 48084 (313) 649-4900 CIRCLE 326 ON FREE INFORMATION CARD new data book on Protection Devices that includes surge and transient sup- pressors. Texas Instruments has a new and free linear products sample packet on their Excalibur series of JFET oper- ational amplifiers. Two great surplus flyers include Alltronics. who are big on powerful magnets and computerized hamsters (their dead ones are cheaper); and Light Machines 669 East Industrial Drive Manchester, NH 03103 (603) 625-8600 CIRCLE 327 ON FREE INFORMATION CARD masterCAM 2101 Jericho Turnpike New Hyde Park, NY 11 040 (516) 328-3970 CIRCLE 328 ON FREE INFORMATION CARD Merigraph Hercules 300 East Shuman, Ste 260 Naperville, IL 60566 (800) 323-1832 CIRCLE 329 ON FREE INFORMATION CARO Quadrax 300 High Point Avenue Portsmouth, Rl 02871 (401) 683-6600 CIRCLE 330 ON FREE INFORMATION CARD Roland Digital 7200 Dominion Circle Los Angeles, CA 90040 (213) 685-5141 CIRCLE 331 ON FREE INFORMATION CARD School Shop Box 8623 Ann Arbor, Ml 48107 (313) 769-1211 CIRCLE 332 ON FREE INFORMATION CARD RA Stewart 641 South Palm, Unit H La Habra, CA 90631 (213) 690-4445 CIRCLE 333 ON FREE INFORMATION CARD 3-D Systems 26081 Avenue Hall Valencia, CA 91355 (805) 295-5600 CIRCLE 334 ON FREE INFORMATION CARD Marlin Jones, who has some new tilt- angle sensors, parabolic mirrors. LCD displays, clutches, and reg- ulators. Our featured free trade journals for this month include Circuit Design on printed-circuit layout techniques, and Nickel, devoted to stainless steel and all other nickel applications. Still at the same old stall after all these years, the Castolite people of- 74 8.398 MHz Crystal SERIAL DATA CLOCK _T O- ANALOG -O OUTPUT SINEWAVE ML2035 SERIAL DATA IN J~l o- DATA LATCH "L O- FIG. 4— A DECEPTIVELY SIMPLE DIGITAL SINE-WAVE GENERATOR. This $8 chip does a full 21-bit phase addition and a 512-level table lookup for an outstanding output quality. Resolution is 1 Hz over a 1-Hz to 25-kHz range! fer all sorts of castable resins and mold products. One good way to get started with the castable resins is to pick up their$75 product sample and evaluation kit. The Circuit Works people have an interesting conductive pen that writes in silver ink. The main use for this unusual gadget is for printed-cir- cuit-board repairs. For some additional mechanical stuff, 3M has an interesting brochure on microcapsule technology, while free plastic-tubing samples are newly available through NewAge Industries. And PM Research has a fine catalog on steam-engine kits. Turning to my own stuff, I have combined my seven top hacking books into a Lancaster Library at a very special price. These include the TTL Cookbook, CMOS Cookbook, Active Filter Cookbook, Micro Cook- book I, Micro Cookbook II, Hardware Hacker II, and, of course, The Incredi- ble Secret Money Machine. Finally, I do have a new and free mailer for you which includes dozens of insider hardware-hacking secret sources. Write or call for info. Our usual reminder here that most of the items mentioned appear either in the Names and Numbers or in the Santa Claus Machines sidebar. As always, this is your column and you can get technical help and off- the-wall networking per that Weed Help?box. The best calling times are weekdays 8—5, Mountain Standard Time. Let's hear from you. R-E Try the MziEntmniESi bulletin board system (RE-BBS) 516-293-2283 The more you use it the more useful it becomes. We support 300 and 1200 baud operation. Parameters: 8N1 (8 data bits, no parity, 1 stop bit) or 7E1 (7 data bits, even parity, 1 stop bit). Add yourself to our user files to increase your access. Communicate with other R-E readers. Leave your comments on R-E with the SYSOP. RE-BBS 516-293-2283 wsss* Data ^ What is the A-Bus? A- Bus is a system for connecting devices to your computer. Whatever your computer, use A- Bus for: Sensing. Detecting or reading a switch closure or voltage presence. Measuring. Determining a force, frequency, temperature, weight, or any other quantity. Control. Open or close a circuit. Switch any type of electrical device. Adjust level or position. Why should you choose A- Bus? It's affordable. From a $65 Digital Input Card to a $299 Motor Controller, you get much more than your money's worth. It's simple, Easy to connect to your computer and to your application. Designed to adapt to your software easily. It's versatile. You mix and match low cost boards to fit your project. It's proven. Thousands of applications installed around the world. Call for a Catalog (800) 221-0916 A Sampling of our Products Relay Card: 8 Individually controlled relays. 3A at 1 20VAC. SPST. RE-140: $1 42 High-Speed 12-bit A/D converter: 8 10/js analog inputs. 0-5V. amp, FA-154: $179 8 Bit A/D: 8 inputs. 0-5. IV in 20mV steps. 7500 conversions/second. AD-142: $142 12 Bit A/D: ±4V. On-board amp. 7 read- ings/sec. i input, expandable AN-1 46: $153 Temperature Sensor :0 -200° TS-111:$12 Digital Input: 8 opto- isolated. Read voltage presence or switch closures. IN-141: $65 Latched Input: Each of 8 inputs is latched to catch switch closures U-157: $85 Dig Hal Output Driver: 8 outputs: 250 mA at 12V. For relays, solenoids... ST-143: $78 Smart Quad Stepper Controller: On board processor controls 4 motors simultaneously. Simple English commands to set position, speed, units, read limits, etc. SC-149: $299 D/A: 4 Channel, 8 Bit Output DA-147: $149 24 line TTL I/O: Connect TTL 0/5V levels or switches. (8255A) DG-148: $72 32 Channel Multiplexer: Switches up to 32 channels to a single common. MX-1 55: $83 Touch Tone Decoder: PH-145: $87 Counter Timer: 3 16-bit counters. Count pulses, measure frequency CT-150: $132 A' Bus Prototyping card: PR-1 52: $1 6 Odin Software: For PC's Control relays from inputs or time schedulesOS-189: $129 Motherboard: For 5 cards. MB- 120: $108 A- Bus Adapters: IBM XT/AT & compatibles. AR-133: $69 Micro ChannelAdapter: AR-170:$93 Parallel Adapters also available for Apple 1 1 . Commodore 64.1 28. TRS-80 Serial Adapter: RS-232 SA- 1 29: $1 49 Serial Processor: Built in BASIC for off- line monitoring, logging. SP-127: $189 o New! C-Net: Connect thousands of RS-232 o serial devices to one computer port. Print- S era, modems, data acquisition devices, etc. 3 Ml ALPHA mrn^M^^ ! 242-RE West Avenue. Darien. CT 06820 § Call (203) 656- 1 806 or Fax 203 656 0756 ° CIRCLE 193 ON FREE INFORMATION CARD 75 AUDIO UPDATE Amplifier Transfer Functions: A Strange Audio Controversy LARRY KLEIN w o z o cc o g 5 < y IEEE dictionary defines transfer function as "a mathematical, graphic, or tabular statement of the influence that a system or element has on a signal or action compared at input and output terminals..." The some- what stilted language refers essen- tially to whatever differences occur between the input and output signals of a circuit. It may seem strange that an Innocuous technical term Hike "transfer function" could in another guise excite such passions in the au- diophile community. It all began, as have several other audio controver- sies in the past decade, with the work of Bob Carver, former president of Phase Linear, and presently the presi- dent and chief engineer of the Carver Corporation. The Carver Corporation When Carver founded the compa- ny that bears his name, he produced two products that both excited audio consumers and rattled a few cages. The first to hit the market was a "sonic holography" preamplifier that provided an enormous extension of the sonic sound stage far beyond nor- mal speaker spacing. In fact, on cer- tain program material, the effect is as though two invisible side-wall speak- ers have been switched in. The holo- graphic illusion is achieved by electronically nullifying the interaural crosstalk that occurs with conven- tional speaker setups. Normally, the sound from the right speaker reaches your left ear and the sound from the left reaches your right ear: the Carver circuit injects some out-of-phase left signal into the right channel and vice versa, thus electronically canceling, when you are properly located, the acoustic "leakage" between both channels. Carver's sonic holograph promp- ted a host of "me-too" products, and variations on the idea are still found in the products of some companies. Not surprisingly, purist audiophiles complained in letters to audio maga- zines that Carver was illegitimately monkeying with the integrity of the audio signal, that the effects achieved were far from realistic, and that the recommended listener posi- tion was unduly restrictive. However, buyers of the Carver sonic-holograph preamp simply enjoyed its effect, un- troubled by the objections of the pu- rists. £_ MUSIC SIGNAL A. MODIFIED AMP 'ft REFERENCE AMP (-) A II NULL SPKR ?H NORMAL SPKR Fig. 1. CONNECTION FOR COMPARING one channel of a reference amplifier to one channel of the modified amp. The nor- mal speakers, whose purpose is to pro- vide a typical load, are placed out of earshot. The null speaker plays only the difference between the two channels. Theoretically, two identical channels will produce no sound from the null speaker. A meter connected across the null speaker has revealed nulls as low as - 70 dB. The Carver challenge Bob Carver's next project was the M-400 "magnetic-field" amplifier. Truly a revolutionary product, it was a 200-watt-per-channel amplifier em- bodied in a 7-inch cube weighing a mere 10 pounds. Once again, au- diophiles who tended to judge an am- plifier's quality by its cost — and the severity of the hernia you got trying to lift it — were outraged. Obviously, there had to be something wrong with the M-400's sound that did not show up in conventional testing, yet was surely audible to anyone with ears golden enough to hear it. Bob Carver told me several times during that period how distressed he was by the self-selected audio es- thetes who felt that he was, at best, a designer of mid-fi equipment. Carver set out to prove them wrong. He de- vised and demonstrated a nullifica- tion circuit (not unlike the Hafler circuit discussed in these pages sev- eral years ago) that would null out all similarities in the signal between any two amplifier channels leaving only whatever differences might exist in phase shift, frequency response, dis- tortion, and/or noise to be heard. I attended at least two of Carver's demonstrations and came away con- vinced that his amplifier was essen- tially perfect in respect to absence of any audible problems. In truth, I was not terribly surprised by Carver's test results since I believe that almost any well-designed amplifier when oper- ated with a reasonable speaker load and within its power rating will sound like any other amplifier also operated under the same conditions. (That is also Carver's view, but he hesitates to propagate it for fear of further al- ienating the irrational self-appointed audio elite.) In any case, Carver made his point among those willing to be convinced. But Carver's test con- vinced none of the audio fundamen- talists whose ultimate faith resides in what they think they hear under their own essentially uncontrolled listening conditions. For this group, only prolonged lis- tening to one amplifier and then the other will allow proper evaluations to be made. Anyone who has attempted to make scientific subjective assess- ments in any product area knows of the pitfalls of such a procedure, but nevertheless, that is the preferred au- diophile evaluation technique. Okay, thought Carver, let's ap- proach the problem from a different 76 direction. He issued a challenge to the editors of Stereophile magazine: You pick out an esteemed high-end power amplifier — tube or tran- sistor — and I will duplicate its sound by minor modifications of one of my current $700 magnetic-field ampli- fiers. Carver flew out to Stereophile's Santa Fe, NM, offices and set up his equipment in a nearby motel, and Stereophile brought over a massive $5,000 tube amplifier to serve as the reference. Several days later, Bob emerged from his instrument- and parts-cluttered motel room with the modified Carver amplifier whose sound he claimed exactly matched that of Stereophile's audiophile tube amplifier. Here comes the surprising part: After hours of comparison listening, the flabbergasted editors of Stereophile reluctantly agreed that Carver had accomplished just what he claimed he would. The sound of the two amplifiers was indistinguish- able even with the "best available" associated equipment and speakers! The implications of what Carver had done was not lost on those who had participated in the event. How could Carver's amplifier duplicate the sound of the reference, without the use of gold-plated connectors and circuit boards, oxygen-free copper wire, capacitors with special di- electrics, and metal-film resistors, and all the other magical elements — including tubes — that are found in au- diophile amplifiers? Could it be, as Carver claimed, that the only thing necessary was to get the proper transfer function? Now for the unsurprising part. Upon reflection, reconsideration, and relistening to the original modified Carver amp plus other samples that Carver had modified similarly, Stereophile's staff decided that the amplifiers really didn't sound alike after all. How could they, when the basic premise of the magazine (and high-end audio) suggests the exis- tence of subtle, mysterious audible dif- ferences that differentiate audiophile equipment from that produced by the "mass merchandisers" such as Car- ver. You wipe out those differences and you obviously wipe out the justi- fication for overpriced and over- designed high-end audio equipment. I asked Bob exactly what he does to match the sound of two amplifiers. Essentially, fie said, the differences he's eliminating are all in the spectral domain. However, that involves more than simply matching the frequency- response characteristics of two am- plifiers. Every amplifier has a charac- teristic complex input and output impedance that causes small fre- quency response variations when driving various speakers and when being driven by various input compo- nents. Matching the sound of two amplifiers consists essentially of matching those impedance charac- teristics. It isn't necessary to work out the reasons for the impedance characteristics of the reference amp, only to duplicate them. Postscript I thought that Carver's approach to amplifier matching would make an in- teresting story and I offered it to Audio magazine. The editor, whom I've known for years, turned me down flat. Why? His belief system, like those of the editors of Stereophile, would not permit him to accept that Carver's feat was possible. And a final note: Since Stereophile re- canted, they have, in Carver's view, constantly attacked his products in editorial comments and reviews. That has led indirectly to a series of legal claims and counterclaims, which, are now being worked out in court. R-E '.'/ think he hives me. . - He let me lemh his stereo. " Cable TV Descrambler Article Parts We stock the exact Parts, PC Board and Adaptor for several articles published in Radio-Electronics magazine on building your own Cable TV Descrambler, February 1984 SB-3 Type 701 Parts Pkg $19.00 Includes all original parts, 702 PC Board 7.95 Original 3X4 etched, drilled and Silk-Screen pc board. 704 AC Adaptor 7.95 J 2 to IS Volt DC ® 200ma. 701, 702 & 704.. ,.,29.00 All three for special saving. February 1987 Tri-Mode 301 Parts Pkg 29.00 Includes all original parts. 302 PC Board 7.95 Original 5XS etched, drilled and Silk- Screen pc board, 304 AC Adaptor 7.95 12 to 18 Volt DC @ 200me. 301, 302 & 304 39,00 All three lot special savings. Tri-Mode Tutorial. .7.95 26 pages of In-depth into. May 1990 Universal 901 Parts Pkg S49.00 Includes all parts. 902 PC Board 9.95 Improved 4X7 etched, drilled end Silk-Screened pc board. 904 AC Adaptor 8.95 12 Volts AC @3S0ma. 901, 902 & 904 59.00 All three tor special savings. Snooper Stopper.. .$39. 00 Prevent Descrambter detection with snooper stopper/data blocker and protect your privacy. Includes free article on Cabte Snooping, Macrovision Kit. -.$29. 00 Macrovliion now you aoo It, now you don't with our macro-scrubber kit. Originally Published in Radio-Electfonics . 70 Channel Cable TV Converter $89.95 fi Function Infra-Red remote. • Fine Tuning. ' Memory & Recall. * Compatible with alt External Descrambter. * Channel 3 & 4 switchable output, * STD, HRC & IRC compatible. CALL TOLL FREE 1-800-332-3557 Outside USA Call 1-508-699-6935 Visa, MasterCard and COD. Add $4.00 S&H, $6.50 Outside USA. D & D Electronics, Inc. PO Box 3310, VISA NIC N. Attleboro, Ma. 02761 CIRCLE 18B ON FREE INFORMATION CARD D R m CD m J! to 77 JililMltJUiMilJ Let's keep our DTMF generator circuit as simple and as elegant as possible. ROBERT GROSSBLATT Just about everyone who owns a computer has had to deal with plug-in cards at one time oranother. Back in the old days, there were no such things as ASIC's Cap- plication specific integrated circuits), and it was even rare to see a board with PAL's (programmable logic ar- rays) on it. Most of the board design- ers and manufacturers produced products that were constructed en- tirely around recognizable hardware. That usually meant that you'd see lots of 74-series logic on the board with an occasional EPROM Ca 2708) to handle unusual gating requirements, data tables, and so on. Things aren't like that any more. Modern boards, and most modern electronic products, are now built around custom silicon since the failure rate is a lot lower and the cost of production is less as well. This is good for the consumer since the products are a lot more reliable and less expensive. A VGA card is an extremely complex circuit but you'll find the parts count to be minimal. The down side of all this is that it's next to impossible to fix any of the newer boards. You not only can't get the ASIC's that form the heart of the design but, even if you could, very few (if any) of such newer boards are de- livered with a schematic and circuit description. The reason I'm mentioning this is because the state of board design has led a lot of people to assume that discrete design is a thing of the past. That's just not true since even the most complex and custom designed boards start out in life as a load of discrete circuitry built around the same MSI (medium scale integration) stuff that, once upon a time, also ex- isted on the final products. The major contribution of the de- velopment of ASIC's has to do with economy, not electronics. The same sort of argument applies to compo- nent density. Not every product made to work with a computer has to be complex. As a matter of fact, Grossblatt's Fourteenth Law— Keep it Simple — tells you that things should be only as complicated as they have to be to get the job done. Not only that, but the more time you spend doing electronics, the more you'll appreciate the advantages you get when you keep things as simple as possible. If the word "simple'' bothers you, think of it as being "ele- gant" instead. The circuitry for the controller we're building doesn't have to be any more complex than is required by the job it's designed to do. We're building a telephone dialer and, although there are certainly an infinite number of things we can have it do, all we're looking for in the beginning is the abil- ity to generate DTMF tones — and we've already talked about all the sil- icon needed to do that. The DTMF generator we're de- signing is basically a two-chip circuit since most of the work is done by the 5088 that generates the tones. Al- though tone-generator chips are a far cry from an ASIC, it would take an impressive amount of silicon to re- place them. < SM4&LE.O #/ /eon -w* o — wr- o— v*\- O— VA- O — \S*- O V»V O—^Ar- O M< V #3 -/?/£> /son. n% -Zoz t-* m$ /OOK zo OE -f-V HO -o-- jtc/ %D3 7¥-LS OS /Z m &£>7 0O Q/\ 6 LE. /» ft /OOK /Z/<7 /6on- AATCS/ 'O— V* /£T a '/ DZ Q3 4 TE ST V-l ZC2, SOS8 GA/a X/ XQ &XTA/. / -j3,S71SVSMHz. FIG. 1— THIS CIRCUIT COMBINES the latch layout we already developed with the 5068. With a bit of simple software, it will generate DTMF tones under keyboard or program control. 78 R-E Engineering Admart Rates: Ads are 2W x ZW. One insertion $950. Six insertions S925. each.TWelve insertions S895.each. Closing date same as regular rate card. Send order with remittance to Engineering Admart, Radio Electronics Magazine. 500-B Bi-County ■ Blvd.. Farmingdale, NY 11735. Direct telephone inquiries to Arline Fishman, area code-516-293-3000. Only 100% Engineering ads are accepted lor this Admart. FCC LICENSE PREPARATION The FCC has revised and updated the commercial license exam. The NEW EXAM covers updated marine anri aviation rules and regulations, transistor and digital circuitry. THE GENERAL RADIOTELEPHONE OPERATOR LICENSE - STUDY GUIDE contains vital information. VIDEO SEMINAR KITS ARE NOW AVAILABLE. WPT PUBLICATIONS 979 Young Street. Suite E Woodburn, Oregon 97071 Phone (503) 981-5159 Dept. 50 Surface Mount Chip Component -=- Prototyping Kits- Only CC-" Capacitor Ku contains 365 pieces b ea. ol every Ifjtya value from Ipf to .33^1. CR-1 Resistor Kit contains 1 5*0 pieces; 10 ea . of every 5% value From 1 QrQ to 10 megD Sizes are 0605 and 1206 Each kit is ONLY $49.95 and available lor Immediate One Day Delivery! Order by loll-free phone. FAX, or mail. We accept VISA. MC, AW EX, COQ or Pre-paid orders. Company PO.'s accepted wilh approved credit. Call for free detailed brochure. T COMMUNICATIONS SPECIALISTS. INC. 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USA 0SB22 FAX: (B021 525-3451 CIRCLE 182 ON FREE INFORMATION CARD CIRCLE 176 ON FREE INFORMATION CARD CIRCLE 192 ON FREE INFORMATION CARD We've already laid out most of the circuit we need to implement our de- sign, and all we have left to do (from the point of view of hardware) is to put it all together. The circuit shown in Fig. 1 combines the latch layout we already developed with the 5088 and, when we add a bit of simple software, will generate DTfvlF tones under key- board or program control. The first four data lines from the parallel port are used to talk to the 5088 through the latch. Even though the latch control of the 373 is brought out to the connector going to the parallel port, we can ignore it for a while by tying the enable line to ground. You can do this with a jumper on the breadboard or. if you want, seven of the pins on the parallel-port connector can be tied to ground. There were originally eight ground pins but remember that we modified one of them CI suggested pin 25) so that it would carry five volts and make it easier to power the circuit we're building. The only thing new in the sche- matic is the colorburst crystal added across pins 6 and 7 of the 5088, That is the only component we have to add to the circuit to make it work. The jumper shown hanging off pin 3 al- lows you to tie the pin either high or low. Making it high will enable the chip to generate DTMF, and making it low will cause the IC to generate the highl- and low-group tones separately. The selection of high or low group is made with the jumper at pin 4. If you tie pin 4 low, the chip will generate the low- group tones, and tying it high will gen- erate the high-group tones. If you make pin 3 high by connecting it to + V, the chip generates DTMF re- gardless of the connection made at pin 4. Although the circuit shown in Fig. 1 still has to have things added to it if you want to do practical things with it (connect it to the phone line, control a telephone, etc.), that doesn't mean it has no use at all. Since it's generating real DTMF. the output of the 5088 can be connected to any circuit that gets driven or controlled by DTMF tones. We'll talk about additional hardware later on but, for the mo- ment, it's time to turn to the software part of the design. Since this is the most basic hard- ware design we'll have for the circuit SOSS DTMF G£MEAA7&A //&VT6 A#0 OUTPUTS *140 3 / tXST £0H> exJ7~~ / 3 C O / / a o t 69"7 a 97 /Z.09 a / 3 o / / o & 7 o / / / 7 S SZ SZ09 <3 y -"> a o 3 3 sz. / 3 3& 9 / o o / 9 3 £ Z. s*<77 a t a / a ^4 9 4- / '3 36 * / o / / s 9 4/ /S. 09 /9 77 /(, S3 /as 3 S633 & 4 / / / / c 9&/ 33 (other refinements will come later), it stands to reason that the software is going to be simple as well. ..at least at this stage of the game. All we're interested in at the mo- ment is writing a few lines of code to tell us whether the hardware is work- ing or not. Since I want to keep things as broadbased as possible, I'll write the software in Basic. Although you're free to drive the latch with any four of the many outgo- ing lines on the addresses that make up the parallel port, we can be nice and logical and use the data port. If the port you're working with is LPT1. the data port is at 3F3CH or 956 deci- mal. Things aren't as clear with the other parallel ports. (LPT2, LPT3, etc.), since the addresses aren't fixed. LPT2, for example, can have its base address at 378h, 278h. or elsewhere. As I talk about software, I'll be re- ferring to LPT1. If you're using a dif- ferent port, you'll have to substitute the proper addresses yourself. The hardware is set to pay attention to only the lower four bits of the data port and, as you can see from Table 1 , the bit combination sent to the port will determine which one of the DTMF tones we generate. The actual code we need to exer- cise the hardware is simple stuff since it's nothing more than a single OUT instruction. All we want to do is send the data shown in Table 1 on the (Continued on page 90) c m o n- 5 w n 33 79 NEXT MONTH IN Exciting Features, Projects, Reports, & Columns • BUILD A BINARY CLOCK A great conversation piece for your home or office • ROLL YOUR OWN RADIO Build a crystal radio using only home- made parts SUPER-SIMPLE FREQUENCY COUNTER Build it as a stand-alone unit or as an add-on for other projects BUILD A SHORTWAVE PRESELECTOR Improve the performance of your re- ceiver with these easy projects And there is more! PRODUCT REVIEWS— Casio co lor- LCD pocket TV, Nikon Hi-8 camcorder, Videonics color equal- izer. Sams Photofacts, and more. OX LISTENING — Business news on shortwave radio. COMPUTER BITS— Do comput- ers interfere with creativity? CIRCUIT CIRCUS— Build a "time- out" circuit, a two-input door-bell an- nunciator, and a simple speak- erphone. HAM RADIO — Adjusting antennas with an RF dip meter. ANTIQUE RADIO— Building your own radio-tube tester. IC SPOTLIGHT continued from page 66 O D < rr PICK UP lU pUittl LlCtllUJlll> AT YOUR FAVORITE NEWSSTAND, CONVENIENCE STORE, OR SUPERMARKET. Chips of a feather... ...come in sets together. Thanks to LSI Logic, you can now build an entire core of a workstation which is binary compatible with the SPARCstation-1 , a reduced instruction-set computer (RISO-based workstation made by Sun Microsystems, from a single 7- chip set. All that's needed to com- plete the system are peripherals and their controllers, boot PROM's, and the main and cache memories. Figure 1 shows a block diagram of the 7-chip system. The chip set includes an integer processor, a floating-point processor, memory-management, direct memo- ry access CDMA), standard I/O and bus controllers, and cache control- lers and tags. At the heart of the sys- tem are two processors, the L64811 and L648T5. The L6481 1 RISC-based integer unit CIU) has 136 general-pur- pose registers organized into eight- register windows. It has a four-stage pipeline, and can execute most com- mands in a single cycle, thus giving it 18-29 MIPS of performance. It also has two coprocessor interfaces, one for a user-definable coprocessor, and the other for the L64814 FPU. The L64814 performs double-precision operations at speeds of up to 6 megaFLOPS at 40 MHz. The FPU's controller section synchronizes the FPU with the IU and provides addi- tional floating-point hardware sup- port. The L64815 is a cache memory- management controller that imple- ments the SPARC Reference memo- ry management unit's CMMU's) virtual address translation mecha- nism as specified by Sun and AT&T Using a 64-entry translation look- aside buffer (TLB), this MMU imple- mentation will be used in all future Sun workstations, and will support the next release of SunOS and UNIX System V, Release 4. The L64815 also provides cache tagging, with the tag memory inte- grated into the IC. There are 2048 usable tags, giving the designer great flexibility in designing the memory subsystem. It can be made up of 32-, 64-. 128-, or 256-kilobytes of com- bined data and instruction cache memory, with line sizes of either 32. 64 or 128 bytes. 80 APPLICATIONS PROGRAMS HARD CPU FLASH MEMORY EXECUTABLES AND OVERLAYS PROGRAM VARIABLES HEAPS, STACKS VARIABLES RAM TEMPORARY DATA DISK r- _j FIG. 2— FLASH MEMORY CAN BE used to store entire programs from disk. RAM is still needed, though, to store program heaps, stacks, variables, and other data that must change randomly throughout the program's run time. The memory manager connects to the memory through a high-speed "M bus," which passes data to and from memory at a blazing 320-rnega- bytes per second at 40 MHz. Pe- ripheral controllers connect to both each other, as well as to the pro- cessors and memory through the Sun-developed "S bus," which push- es data through at 100-megabytes per second at 25 MHz. The L64852 Mbus-to-Sbus con- troller is used to control the two buses. That IC has five primary func- tions: 1. to act as an Mbus arbiter, 2. to act as an Sbus controller, 3. it is an Mbus and an Sbus master/slave con- troller and data buffer, 4, it provides Mbus-to-Sbus protocol conversion, and 5. it is used for I/O memory man- agement. The set is rounded off by a main- memory controller, the L64850, a Standard I/O controller, the L64851 and a DMA controller, the L64853, which connects to a small-computer systems interface (SCSI) and local- area network CLAN) controller. Two versions of the system are the Spar- KIT-25 and the SparKIT-40, which provide 18 and 29 MIPS of perfor- mance, respectively. Both chip sets are used in LSI Logic's proprietary 0.7-micron HCMOS process. The SparKIT-25 is $1,327.00 per kit. in 1000-unit quantities. Memory in a flash As new types of microprocessors hit the scene, so too must new types of microcomputer memory to sup- port them. One such new type of memory is the flash memory from In- tel. Touted as non-volatile RAM. these devices are more similar to a higher-speed, lower-cost EEPROM's. The chips are non-volatile in nature and data can be read randomly, but that's where the RAM similarity ends. Writing and erasing has to be done to the whole chip at once. Erasing an entire 1 -megabit chip takes one sec- ond, while writing data to that whole chip takes four seconds. A possible application of flash memory is shown in Fig. 2. Flash memory can be used to store entire programs from disk, which the CPU runs as if it were from RAM. RAM is still needed to store program heaps, stacks and variables and other data that must change randomly while the program is running. Since they can't be written to ran- domly, flash memories will not likely replace all of the RAM in any sys- tems. They can be of great use, how- ever, in reducing PC-board real estate in workstations that need a lot of memory to store running applica- tions. Such applications will, of course, have to be rewritten to map temporary memory contents into RAM and keep executable and over- lay files in flash. Of course, their first application will likely be as nonvolatile backup memory that will come into play in the event of a power failure or as storage in laptop computer sys- tems. The typical cost of Intel's flash memory chips varies according to the memory density. The price for a 1- megabit 28F010 is $18.70, and is sold in a DIP package. A 2-megabit 28F020 costs $34.80 in a DIP pack- age, and $45.20 in a thin small-out- line package CTSOP) used in surface- mount technology CSMT) designs. All prices are for 10,000 unit quantities. We'll see you next month for a look at the all but forgotten world of analog multiplier IC's and the role they play in phase-locked loops. R-E EARN YOUR B.S.E.E. DEGREE THROUGH HOME STUDY Our New and Highly Effective Advanced-Place- ment Program for experienced Electronic Tech- nicians grants credit for previous Schooling and Professional Experience, and can greatly re- duce the time required to complete Program and reach graduation. No residence schooling re- quired tor qualified Electronic Technicians. Through this Special Program you can pull alt of the loose ends of your electronics background together and earn your B.S.E.E. 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C-64 & 128 and more. 416 pp. ELECTRONIC CIRCUITS tn o z o rr H 4 100 ns 5.95 EPROM 27C1000 128K*B 200 ns $15,001 27512 6iK»8 200 ns 7.10l 27256 32K«s 200 ns 5.40 1 27128 tbKxs £50 ns 3.7S1 STATIC RAM 6Z256P-10 32K*8 100ns S6.50] 6264P-12 BKiB 1 20 ns 4.2SJ OPEN 6 DAY 5, 7 » tu. 1 p» SHIP V I A FED- EX N SAT HT DEL OH FED-EX ORDERS RECEDED BV lrE» ffhHib lr M IlT»1» COD AU*HA0k.E Wa-jiarCi--; VtSA c UPS CASH i MICROPROCESSORS UNLIMITED. INC 24.DDT1 S PtJOriaAw " BEGGS OK 7**21 No minimum ordtr. JUriJ LJ "!l.irVM I ELLS. MUl-h (918)267-4961 CIRCLE 61 ON FREE INFORMATION CARD modes: 1 ) single step, in which one bit is delivered each time you click on the step button; 2) burst, in which all 16 bits are delivered sequentially; and 3) cycle, in which all the bits are output repetitively. The output of the flip-flop is con- nected to a logic analyzer, a zoomed- out view appears behind and the pulse generator. The pulse generator drives channel one (shown in the up- per trace) of the logic analyzer, the output of the flip-flop drives channel two (lower trace). Logic-analyzer op- tions include positive, negative, and external triggering, and a display of the waveform, either as received or after receiving a pattern. On-line Kelp EWB includes a top-notch on-line hypertext-based help system. Note that the text box of Fig. 1 describes the "JK Flip-flop". To get that type of description, you simply highlight a component and press F1 . In that text box, the word theory is highlighted. You can click on it to receive a more- detailed description. It's hard to see in the figure, but "RS flip-flop" is high- lighted as well. You can also click on it for comparative information. The help texts are brief summaries, so they are not really substitutes for full textbook explanations. However, the manual includes complete instructions for modifying and adding to the built-in help texts. Moving from right to left, the icons in the upper right corner of the screen allow you to scroll through the parts bin, scroll the screen, start simula- tion, and drop down a command menu. The command menu allows you to get help; cut, copy, move, and rotate components; set preferences; and load, save, and print files. All common laser and dot-matrix printers are supported. Moving from left to right, the icons in the upper left corner represent test instruments. First is a DVM, then the pulse generator, then the logic ana- lyzer, then the "truth table." The lat- ter converts digital circuits among three different representations; a cir- cuit diagram, a truth table, and a FIG. 2— EWB'S ANALOG MODULE IS SIMILAR to the digital module except there are more components and different test instruments. Meter characteristics are ideal, but you can change their impedances to simulate real-world operation. o m o m CD O 87 SPECIAL FROM ETT n PCP101— PRACTICAL DIGITAL ELECTRONICS HANDBOOK ... S9.9S. In- troduces digital circuits, logic gates, bistables and timers, as well as micro- processors, memory and input/output devices. Spe- cial section on digital test near projects n PCP102— INTRODUC- ING DIGITAL AUDIO ... $9.95 Snows what is in- volved in the digital part o( audio signals, particularly in the newest devices such as CD. DAT and sampling. Bridges the gap of under- stand i ng fo r the tech nici a n and enthusiast. : PCP103— PRACTICAL MIDI HANDBOOK ... $9,95. Covers all MIDI based equipment you can use — keyboards, drum machines, sequencers, effects units, mixers, drum pads and guitars. Also a section on comput- er music that covers soft- ware and more. n PCP1(M _ ELEC . TRONICS BUILD & LEARN, Second Edition , „S9, 95, You starl by as- sembling a circuit demon- strator that is then used to build and investigate a va- riety of useful circuits in- cluding oscillators, multi- vibrators, bistabies and logic circuits. □ PCPtB5 — MAKE MONEY FROM HOME RE- CORDING ... $10.(10. Now that you've spent all that money on all that record- ing gear, wouldn't it be nice to get some of it back? Well here's the bonk that can show you how. □ PCP10S— SYNTHE- SIZERS FOR MUSICIANS ... S1Q00. All current popular forms of syn- thesis explained: LA, ad- ditive, phase distortion, FM and sampling. Get the sounds you want from your synth. Written es- pecially for musicians. MAIL TO: Electronic Technology Today, Inc. PO Rox240 Massapequa Park. NY 11762-0240 SHIPPING CHARGES IN USA AND CANADA 10.01 to $5.00 $1,25 $30.01 to $40.00 $5.00 $5 01 to 10.00 S2.00 $40.01 to $50 00 $6.00 $10.01 to $20.00 $3 00 $50.01 and above $7.50 $20.01 to S30.00 $4.00 SORRY, No orders accepted outside of USA and Canada Total price of merchandise ... $ _ Shipping (see chart) $ . Subtotal $ . Sales Tax (NYS only) $. Total Enclosed $ . Name Address . City .State . -Zip. Boolean expression. You can create a circuit by filling in a truth table. On the other hand, you could attach it to a working circuit, get a truth table, and verify your design. EWB uses the Quine-McCluskey synthesis al- gorithm when going from a truth table to a Boolean expression. You can place only one copy of each test instrument into a circuit, but after running a simulation, you can measure signals at various points as long as you don't change the cir- cuit itself. Analog module The analog module works similarly, but there are more components and different test instruments. Compo- nents include resistor, capacitor, in- ductor, transformer, NPN and PNP transistors (but no FET's or MOS de- vices), diode, Zener diode, op-amp, battery. AC and DC sources. Test instruments include a function gener- ator. DVM. dual-channel scope, and Bode plotter. There are volt meters and am- meters in the parts bin; multiple cop- ies of each may be inserted into a circuit. The function generator pro- vides sine, square, and triangular waves; the frequency can range from 1 Hz to 999 MHz; you can also adjust the duty cycle, symmetry, amplitude, and DC offset. The DVM measures current, voltage, resistance, and dB. By default, meter characteristics are ideal (infinite impedance for voltage measurement, zero for current), but you can vary characteristics to simu- late real-world conditions, and that's a nice touch. Similarly, you can alter the operating parameters of the ac- tive components, and load and save different models of the same compo- nent. Conclusion EWB is a wonderful program. It is limited in that you can't model very large circuits, nor (in the digital mod- ule) can you account for propagation delays, so you would never be able to model a high-speed 32-bit wide 486 bus. But that's not what EWB is intend- ed for. It's really intended for first-year college or university students coming to grips with the fundamentals, and in that sense, works admirably. At $650. EWB is much too expensive for individual purchase. I have dis- cussed that with Interactive Images, and they are working on a lower-cost version. I'd strongly urge you to write to the company as well. IF the company sees a great deal of interest in the product, they would be more inclined to believe that they can make up through volume what they lose in the per-piece price. Books from Abacus Press I have just had the pleasure of per- using a couple of thick, dense books written by Michael Tischer and pub- lished by Abacus press: PC System Programming and Turbo Pascal Inter- nals. Tischer's stated goal in PC Sys- tem Programming is to provide a complete system overview, including detailed information on hardware, BIOS, and DOS. Although that is an ambitious goal. Tischer for the most part manages to achieve it. The book consists of more than 900 pages of lucidly presented information with lots of example pro- grams in assembler, C, Basic, and Pascal. All programs listed in the book (about 1 MB total) are included on a pair of floppy disks, which elimi- nates tedious and error-prone typing. For example, the book contains an excellent discussion of device drivers (with examples), a set of routines for determining video-card type, using extended and expanded memory, de- termining CPU type, hard-disk parti- tioning, and a whole lot more. All in all, these books put to shame certain well-known volumes by certain well- known industry personalities. The Pascal book provides equal meat. For example, Tischer shows dis- assembled versions of standard Tur- bo functions and procedures, il- lustrating why DEC and INC are more efficient than PRED and SUCC, as well as X : = X + 1 . Major topics include a complete window manager, a swap unit that al- lows your Turbo program to shell to DOS with a maximum amount of memory by leaving only a 1K stub behind, and another unit that allows you to build a multi-tasking system under Turbo. Turbo Pascal Internals has about 750 pages, and also comes with about 1 MB of source code. Neither book is for the begin- ner. However, iF you've already mas- tered the basics of PC hardware and software, these books can provide a one-stop source for moving up to Guru status. R-E MEMORY QUIZ Find out how much you know about random access memory. ALV N E. SYDNDR 1 — Most popular RAM devices are available in two types, which are: (a) metal-oxide semiconductor CMOS) Cb) 64K bytes (c) bipolar Cd) high-power 2 — In dynamic memories, each stor- age cell is composed of: Ca) PNP ICs Cb) a single MOS (c) a MOS-processed capacitor Cd) silicon chips 3 — The term "performance" relates to how fast the RAM can operate in a given environment. That parameter is usually rated in terms of: (a) bits per second (b) transfer time Cc) time-temperature Cd) access time 4 — Bipolar memories offer very high performance but have the disadvan- tage of: Ca) being very bulky Cb) operating at high voltage levels Cc) high power dissipation Cd) limited storage 5 — The great advantage of dynamic RAM's (DRAM) lies in: Ca) long-term memory storage ca- pabilities Cb) the small size of their storage cells Cc) low- voltage operation Cd) a long "refresh" time 6— The term "RAM organization" re- fers to the: Ca) physical size of the chip Cb) method of manufacturing (c) grouping of the cells Cd) width of the memory word 3-U -sjiq lx>ju se paziuefjjo ai9M s[A|vtl 'uoiidsoui A\ -jeaJjagiOuunQ pjoMAjoiuaiueu,} p LjipjM aq; oi ssapj uo^ezjueOjo ^ VH ■Ajba ueo s ,^vtl 9^!13E jo jaqiunu pejmbaj aqi 'aojAap am p uou -eziueSjo aqi uodn buipuedaQ (p) — g lAjyy oijejs p ieu,} 0} pajedoioo ;soc aq; saonpaj AiiueoujuBjS os|e smx sajiisuap lj6|L] aAaiqoe o} a|q|ssod }! sa>jeuj qoiUM 's||ao aBejo^s j|9qj p az|S ||eujs aqi u\ sa|| |/sjyy oiweu -Ap p aSejueApe ieai6 9uj_ (q> — g •aojAap Ajoujsuj 201N a ^e -j9ab aqi ueio. jaMOd aJQW AiiueDtriu -6is aiedjssjp pue A>|]nq Apiej aje jnq 'saiiiiiqBdeoaoueLUJojjad-qBiq-AjaA jajjo sauoiuauj Jepdig ro pue B) — f TldO aqi luoj-( puBLuiuoD 8)umjo peai B O} puodsaj oi (Ajvy au ,J sa>|e} J! 6uo| molj 'S| }ei|} :aLU|} ssaooejo sujjai ujj pajBj X||ensn s\ japujejed sim iubujuojia -ua wajsAs u9A|6 e ui ajejado ueo ^\l\/y aqi isej Moq o; saiG|ai aoueoi -jojjad LUJ9} aq} 'A||Bjaua[) rp) — £ uoipedeo passaoojd-goiAl Ainj e P ue C13JSOI/N) JojsisuBj} joays-piay jopnpuociiuas apixo-|e^9UJ a|6uis B p pasodiuoo s\ ]|90 abejois upea 'S9U0LU3LU DiOIBuAp U| (0 pUB q) g sajBoiouqoa} SCOT P ue JS|od|q asn saojAap y\|yy jB|ndod }uajjno om aqx p pue e) — i SJ3MSUV r &&* ^0 CIRCLE 108 ON FREE INFORMATION CARD MEANS A LOT TO YOU Because We Provide • Better Facilities • Better Quality • Better Service • Better Prices on JAN CRYSTALS Radio Control Microprocessor Industry Telecommunications Marine Satellite Amarteur Two-Way WRITE OR CALL FOR FREE CATALOG JAN CRYSTALS P.O. 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Use your free information card num- ber, or write us directly. $99.95, Postage Included Satisfaction guaranteed or money refunded. AAA/ Banner Technical Books, Inc. 1 203 Grant Ave. Rockford, I L 61103 CHRISTMAS CARD continued from page 47 the microphone causes a voltage to appear. Do not increase the setting until R17 through R20 are adjusted so as to give a com- plete range through each bar- graph. The best bet for making these adjustments is to play a stereo audio source (actually, any source will do) at a normal listen- ing level. Simply adjust the po- tentiometers for what you con- sider to be a pieasing or most Christmas-like interpretation of the sound. If you have any problems with the device, the first thing to do is decrease the setting (counter- clockwise) of all the potentiome- ters. A filter that still oscillates after decreasing the potentiome- ters most likely has an incorrect component or one that does not meet its tolerance. For high-Q versions of the cir- cuit, sometimes the component tolerance is such that the filter will begin to oscillate when pre- sented with a large input. If that's the case, all you must do is inter- change the two filter capacitors; this old technician's trick usually works, assuming that there aren't any problems with the other components. If you still have problems, check that the analog ground is stable. A variation on that line will cause serious problems with the operation of the unit. If you cannot find the problem, the best thing to do is to shut off the dis- play by lifting one lead of both Rl and D5. With the load of the dis- play removed, it's easier to locate problems. The finished, working board can be installed in any kind of housing you like, although the custom black metal frame adds a nice touch, as does the mat that keeps the circuitry from view. After installing the unit in the frame you may want to readjust the potentiometers, since the frame and front glass seem to couple the microphone to the surrounding air. Vibrations picked up by the device will also produce a display; a fan operat- ing nearby is almost always dis- played. Have fun, and don't forget to have a merry Christmas, as well! R-E DRAWINC BOARD continued from page 79 lower four bits of the data port associ- ated with the parallel port you're using (LPT1 in this example). Since the four most significant bits at the data port aren't being used Cat the moment), it doesn't matter what value we give them. I'm mentioning this only because the OUT instruc- tion will send a full byte out to the port. An instruction such as OUT 956.1 will send the same four least- significant bits to the port as an OUT 956,177. Those two numbers may look very different but the similarity between the two shows up when you think of the numbers in hex instead of decimal. Since you want the lower half of the byte to be a 1h, any number can be stuffed in the upper half of the byte. A 177 decimal is B1h, so it will be the same (as far as our circuit is con- cerned) as a 01 h, 21 h, 31h,andsoon. The output of the 5088 can be fed into the line input of a standard ampli- fier or, ifyou'reaDTMFfreak.youcan probably connect it to a set of high- impedance headphones. There's no guarantee of the initial state of the lower four bits so there's no telling what tone you're going to hear when you first connect the circuit to the port. If you've wired up everything prop- erly, you'll hear the tones change as you send different data out the port but, as you may have noticed, all the possible values you can put on the lower four bits are legal input codes for the 5088. That means there's nothing you can send to the port to shut the circuit off. While that won't cause any electronic problems, it can still cause a bit of brain damage. There's an easy way around that how- ever, since the tone enable input Cpin 2) is specifically designed to take care of the problem. You can tie that pin to one of the other data lines — bit 7 is a good choice — and use that data line to turn the chip on and off, A high on the data line will enable tone generation and a low will disable it, no matter what data is being sent on the lower four bits. When we get together next time we'll finish this thing off by adding some circuitry to control the phone line, a telephone, and a few other things. See you then. R-E 90 CIRCLE 67 ON FREE INFORMATION CARD MARKET CENTER FOR SALE DESCRAMBLERS. All brands. Special: Combo Jerrold 400 and SB3 $165,00, Complete cable de- scrambler kit $39.00 Complete satellite de- scrambler kit $45.00. Free catalog, MJM INDUSTRY, Box 531, Bronx, NY 10461-0208. TUBES: "oldest," "latest." Parts and schematics SASE for lists, STEINMETZ, 7519 Mapiewood Ave., RE, Hammond, IN 46324. ENGINEERING software, PC/MSDOS. Hob- byists — students — engineers. Circuit de- sign S49.00, PCB layout $99,00, Logic simulation $29.00, FFT analysis $69.00, Mathematics $39,00, Circuit analysis $29.00. Call or write for free catalog. (614) 491-0832, BS0FT SOFTWARE, 444 Cotton Rd., Columbus, OH 43207. RESTRICTED technical information: Electronic sur- veillance, schematics, locksmithing, covert sci- ences, hacking, etc. Huge selection. Free brochures. MENTOR-Z, Drawer 1549, Asbury Park, NJ 07712. CABLE TV DESCRAMBLERS! BARGAIN HEADQUARTERS! •JERROLD™ •TOCOM •HAMLiN •OAK »ZEN[TH • SCIENTIFIC ATLANTA 6 month warranty! We ship C.O.D.! Lowest retailMholesale prices! FREE CATALOG: Global Cable Network 1032 Irving St. Suite 109 S.F., CA94122 NO CALIFORNIA SALES!!! ORDER TODAY! 800-327-8544 CABLE TV converters: Jerrold, Oak, Scientific At- lantic, Zenith & many others. "New MTS" stereo add-on: mute & volume. Ideal for 400 and 450 owners! 1 (800) 826-7623, Amex, Visa, M'C accept- ed. B & B INC., 4030 Beau-D-Rue Drive, Eagan, MN 55122, TUBES, new, up to 90% off, SASE, KIHBY, 298 West Carmel Drive, Carmel. IN 46032. CABLE TV converters and descramblers. We sell only the best. Low prices. SB-3 $79.00. We ship C.O.D. Free catalog. ACE PRODUCTS, P0 Box 582, Dept. E, Saco, ME 04072. 1 (800) 234-0726. CB RADIO OWNERS! We specialize in a wide variety of technical information, parts and services for CB radios. 10-Meter and FM conversion kits, repair books, plans, high-performance accessories. Thousands of satisfied customers since 1976! Catalog $2. GBC INTERNATIONAL P.O. BOX 31500RE, PHOENIX, AZ 85046 PHOTOFACT folders under #1400 S4.00. Others $6.00. Postpaid. LOEB, 414 Chestnut Lane. East Meadow. NY 11554. FM 2-way, CB/amateur, scanners, radar detec- tors, auto alarm, catalog S1.00, RAYS, PO Box 14862, Fort Worth, TX 76117. CABLE converters, all major brands. Info & orders 1 (BOO) 782-0552. FREEWAY, INC., SMP PO# 5036. Bumsville, MN 55337. S-A test chips. Enables full tiering. 8550: $22.00 each/10 $180,00. 8500: S20.00 each/10 $160.00. Money order or COD. R.V., Box 771, Ridgefield, CT 06877. S1.99 software for IBM Compatibles, Quality at af- fordable prices! Huge selection: business, games, graphics, utilities, database, spreadsheets. Free catalog. AULT, 1556 Halford Avenue, #242, Santa Clara, CA 95051. ROBOTICS software, PC/MSDOS. Explore com- puter vision, sonar sensing. Free brochure. ROBOTS ETC., Box 122, Tempe, AZ B5280, IS it Irue jeeps for $44.00 through the U.S. Gov't? Call for facts! (504) 649-5745 Ext. S-5192. ARTIFICIAL intelligence (or IBM/PC. "Uncanny and fun" - N.Y. Times. Free 32-page catalog. THINK- ING SOFTWARE, 46-16 65th Place. Woodside, NY 11377. FREE CATALOG FAMOUS "FIRESTIK" BRAND CB ANTENNAS AND ACCESSORIES. QUALITY PRODUCTS FDR THE SERIOUS CB'er. SINCE 1962 FIRESTIK ANTENNA COMPANY 2614 EAST ADAMS PHOENIX, ARIZONA 85034 PROGRAMMABLE stepper motor drive & control for under S100. IBM PC/XT compatible, Com- modore 64, or other with 25 pin parallel port. PCB, interface, & software. Send for detailed literature to: MASE, R.D. #2 Box 166. Mohrsville, PA 19541. PRINT ED circuit boards etched & drilled. Free deliv- ery. K & F ELECTRONICS, INC., 33041 Groesbeck, Fraser, Ml 48026. (313) 294-8720. LASERS. Imw to 2kw, worlds largest selection of new S used surplus. Free catalog. MWK INDUS- TRIES, 1269 Pomona Road, Corona, CA 91720. (714) 278-0563 C A B LE descramble rs ( Jer rold) f ram $4 0. 00 . Tocom VIP test chip. Fully activates unit. Also Zenith lest board. Fully activates Z-Tacs. $50.00. Call (213) 867-0081. Quality Microwave TV Antennas : WIRELESS CABLE - 1FTS - MMDS - Anutiur TV 1 Urtn High Slit! M*(+] - Tiumblt 1.9 to 1.7 Gfti. M • 36 -CM to System Com pie! j 5! -1 9 55 h^^ft. • -2-ChBin*- System Complele 51 U 95 ■ Call or wile [SASE) for "FHEE" Catalog ■ PHILLIPS-TECH ELECTRONICS ^W P.O. Box 8533 ■ Scottsdale, AZ 85252 lifetime (602) 347-7700 (I3.M Credll ill ptma onlirt] WARRANTY MaxlerCanl ■ Viu * COP'J > DiHitlFf Pricing TEST equipment pre-owned now at affordable prices. Signal generators from $50.00. Os- cilloscopes from $50.00. Other equipment, includ- ing manuals available. Send $1.00 for catalog, refund on 1st order J.B. ELECTRONICS, 3446 De- mpster, Skokie, IL 60076. (708) 982-1973. TV. notch filters, surveillance equipment, Prochure $1.00. D.K. VIDEO, Box 63>'6025. Margate. FL 33063. (305) 752-9202. MINIATURE electronics like James Bond. Catalog $4.00, refundable. F & P ENTERPRISES, Box 51272, Palo Alto, CA 94303-L. TOCOM VIP converters w/remote from $279.00. Tocom super chips turn on everything, $69.00 each. Phone (219) 935-4128. DESCRAMBLERS, below wholesale prices, ail brands, example RTC-56 combo $150.00. M35B S39.00, full warranty, CODs welcome, MOUNT HOOD ELECTRONICS (503} 253-0459. GREAT buys! Surplus prices, transformers, tubes, fans 12VDC, stepping motors, vacuum pump, mag- net wire, braid. LSASE. FERTIK'S, 5400 Ella, Phi- la., PA 19120. WIRELESS CABLE RECEIVERS 1.9 TO 2.7 GHz □ 30 CH PAHABOLIC OISH SYSTEM S173.gcf 30 CH BOO ANTEti ItA SYSTEM SI 93. 90 3OCHCnYSTAL.C0NTfi0LLED5YSTEMS294.g5 MIS MICROWAVE INI1 INC. SEND SI CD FOE PC. BOX »)tm CATALOG OH THESE mOENII.A2.K05; AND OTHER FINE |602l msM VIDEO PRODUCTS ODABTJTY DISCOUNTS MHat of ix una wsucss tmav CALLER ID unit - identifies the phone number of incoming calls on a display before answering the phone. ED E, PO Box 337, Buffalo, NY14226.7716) 691-3476. CABLE TV converters & descrambiers for Jer- rold and Scientific Atlanta. Low prices, one year warranty. We ship COD. BAY STATE ELEC- TRONICS. PO Box 103, Boston, MA D218B. 1 (800) 359-9606. BLACK market, hacking, phreaking. weapons, electronic surveillance, communications, more. Hardware, software, plans, kits, books. $1.00 cata- log: OMEGATECH, PO Box 8789C, Woodlands. TX 77387. CABLE T.V. CONVERTERS WHY PAY A HIGH MONTHLY FEE? All Jerrold, Oak, Hamlin, Zenith, Scientific Atlanta. Magnavox and all specialized cable equipment available for shipment within 24 hours. For fast service MC7 VISA or CO. D. telephone orders accepted (B00) 646-3030 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. irrnDUjl'sT SimT l €L€CTRonic5inc. ^; e t S e . IL6mi0 No Illinois Orders Accepted. LOST control of your home en. ter? Send for a free brochure ol in controlled switching products to: I. RE, Box 1205, Richardson, TX 7 437-3366. ainment cen- ■"vative, remote rlACON, Dept. 35-1205 (214) SCREWDRIVERS: put a thick piece of latex rub- O ber on your shaft. For safer, smoother screwing. S Enclose $5.95 per set, offer #102 M&M PRODUC- — TIONS, PO Box 151. Waldron, IN 46182-0151. Please include $2.00 SM TOCOM VIP test chip with Torx #7 wrench $45.00. R&S (817) 293-4113. No Texas sales. CO m CO to o 9t Cable Descramblers New Auto Trj-Bi guaranteed no Hashing $165*00 ZENITH SUPER SAAVl J199.C0 TOCOM 1319.00 EAGLE „ $119.00 COPY GUARD $59.95 STARGATE 2000.,, S8S.00 SB-3 $99.00 TR1MODE $109.00 HAMLIN $99.00 SCIENTIFIC- ATLANTA $119.00 OAK M35B.„ $99.00 ZENITH..... $175.00 M. It. Electronics will match or beat any advertised wholesale or retail price. Your best buys and warranties for cable converters and descramblers start with a FREE catalog from MD For Information Call 402-554-0417 To older or request a free catalog 1-800-624-1150 EXCELLERATOR CABLE CONVERTERS WHEN QUALITY COUNTS Q Am $&*****?<> 1*» New Dyna track™ fine tuning provides unmatched picture qua lily 550 Mhz tuner provides S3 channel capacity Sleep timer for automatic shut off within 1 5-90 minutes 2/3 switchable ICRC / IRC /Standard Switehable 2 Year warranty, Last channel recall. Favorite channel select. Scan Double vented high efficiency transformer Tor cool performance Stargate-2001 $99.00 Stargate-550XL $119.00 With Volume Control Don't settle for anything less. M£i£EUEER»»Br' LTIHBB c.o.d ^ B73 SO. 72nd St Onuha, NE 6STV4 kVCKDEIcJ^KCAIliTVSQLTFMENTraDMMD UCDBMCOTHllfllt&JISn AGREES 7G COMPLY W mi ALLSTATE AND ft DtKAl LAWS KECAKIXNC PRIVATE OWNPSIDPWCAiUTVKJLTPMET EF YOLI *M UNSUItt OF 71 fiSt LAWS CmCK WTTM TOtm LOCAL OFFICIALS CIRCLE 53 ON FREE INFORMATION CARD CO o z o EC g LU o 5 < EC CABLE TV TB-3 (Tri-Bi) or SA-3 Quantity Prices 10 20 $48. $43 Each 50 Each 100 3)w*7b %POda Each Each Hours open 10:00 am to 4:00 pm Eastern time Minimum order 5 units 55.00 ea. Dealers wanted. We ship COD. King Wholesale 1-800-729-0036 Fax number 6173400053 "No one beats the King's prices!" DESCRAMBLERS Try the Electronics bulletin board system (RE-BBS) 516-293-2283 The mote you use It the more useful it becomes. We support 300 and 1200 baud operation. Parameters: SN1 (S data bits, no parity, 1 stop bit) or 7E1 (7 data bits, even parity. 1 slop bit). Add yourself to our user tiles to increase your access. Communicate with other R-E readers. Leave your comments on R-E with the SYS0P. RE-BBS 516-293-2283 PROTO QUICK 28, single board computer with pro- totype area, $69.00, SOFTWARE SCIENCE, 3750 Roundbollom Road, Cincinnati, OH 45244. (513) 561-2060. FLUKE Model 73. 75. 77. s 68 *99 s 135 83.. 85.. 87.. VISA s 180 s 208 =246 ▲ NEWl Model 45 . . . '535 ▼ ■ ■ £ KEL VI N Electronics ■ u "7 Fa-rciiild Ays . flainview. NY ttaoj ^■■(516) 349-7620 1(800)645-9212 RADIO tubes, parts. Extensive listings. $1. 00 (re- fundable). DIERS, 4276- E6 North 50th Street, Mil- waukee. Wl 53216-1313. BOOKS on Tesla coils, lasers, robotics, elec- tronics, computers & more! Write: Free catalog. Box 596-R, Logan, Utah 84321. 1 (800) 359-0466. FREE catalog: Save hundreds on sought alter elec- tronic, electro mechanical, and computer related hardware and components — including hard-to-find items. Call toll free: 1 (800) 776-3700. AMERICAN DESIGN COMPONENTS/ Depl. 119-120, B15 Fair- view Avenue, Fairvrew, NJ 07022. CABLE TV "BOXES" Converters — Descramblers Remote Controls— Accessories * Guaranteed Best Prices * * 1 year Warranty — C.O.D ,'s * * Immediate Shipping * * FREE CATALOG * Call or Write TRANS-WORLD CABLE CO. 12062 Soul riwest 117th Court, Suite 126 Miami, Florida 33186 1-800-342-9333 VCR technicians. Tech lip to remove any Fisher idler wheel quick. $5.00. BERGE SYSTEMS, PO Box 95, Buitalo, NY 14205. PREVENT burglaries! Practical home security quide. Topics from burglar techniques to alarm in- stallation. Free details! MIDNIGHT RESEARCH, 4129 NW 88th Avenue, Suite 282, Sunrise, FL 33351 . CABLE TV brokers and distributors high volume of descramblers Jerrold SB-3 refurbished or as is. con- verters Jerrold models DRX-400. JRX and hand remote control [no Canada sales for descramblers). Affitech. ask DANIEL PERREAULT (514) 656-9510. KITS, MC68701 programmer $135.00, morse code keyboard $75.00, ten meter FM conversion $25.00. SINGLE CHIP SOLUTIONS, Box 680, New Hartford, CT 06057-0680. CABLE DESCRAMBLERS OAK M3SB COMBO S39.95 Jerrold, Zenith, Hamlin, Sci. Atlanta, Pioneer & MORE! OUR PRICES ARE BELOW WHOLESALE! CABLE-*- PLUS 14417 Chase St. #4B1-A Panorama City. CA 91402 1-800-822-9955 • Other Info. 1-818-785-4500 NO CALIF. SALES - DEALERS WANTED DESCRAMBLER specials, RTC-56 combo $150.00, M-35-B combo $39.00, Tocom 5503A combo S200.00. 5501 descrambler $115.00, Jer- rold 400 combo $125.00, Hamlin CRX-6600 com- bo $125.00, Zenith Z-Tac $225,00. Tri-Bi super fast $79.00, SA-3-B $79.00. Information (702) 647-3799, orders only 1 (800) 622-3799 S.A.C.. 92 DESCRAMBLERS ***** STARRING ***** JERROLD, HAMUN, OAK AND OtHES FAMOUS WANUFACTUWEBS • RNf ST WWfiAVTT FWOCIWM «UN1A»LE • LOWEST F-F7AJL. 'AVtOLE^ALE HUCCS IN U.S. • CHOCK SHIPTED FflOtf STOCK ttTTHIN H MCXJ"S FOW FKIt CATALOG ONLT 1-S00-345-S9 2 7 ton ALL INTOmWATtOW 1->H-709-993T/ SATELLITE TV - — - PACIFIC CABLE CO., INC _- — , t ■ J 732SMi Reseda Blvd., Oept.1000 pa^ -■— -■ Reseda, CA 91335 SCANNER buffs, national and international fre- quency listings with allocations. Send $11.00 U.S. for booklet to: BOX 1051, Station C, Kitchener, On- tario, N2G 4G1 Canada. ARTWORK created for use in printed circuit board production from your engineering schematics. Pro- fessional quality hardcopy, gerberfile, or photoplot- ter outputs, Reaonable rates. Send tor details to: JTD ENGINEERING, 10623 Grandview Place, Alta Loma.CA 91701. SURPLUS educational equipment, shortwave re- ceivers adjustable 50 to 70 MGHZ, 6 meter, with private line. Information! ELECTRO TECH SCHOOLS, 120-N. Mechanic Avenue, Alliance, OH 44601. INVENTORS INVENTORS! Can you patent and profit from your idea? Call AMERICAN INVENTORS CORPORA- TION for free information. Over a decade of service 1 (800) 338-5656. In Massachusetts or Canada call (413) 568-3753. VIDEOCIPHER II manuals. Volume 1 - Hardware, Volume 2 - Software - either $34.95. Volume 3 - Projects/Software, Volume 5 - Documentation or Volume 6 - Experimentation 544.95 each. Volume 4 - Repair 599,95. Cable Hacker's Bible -$34.95. Clone Hacker's Bible - $34.95. Catalog - 53.00. COD'S (602) 782-2316. TELECODE, PO Box 6426- RE, Yuma, A2 85366-6426. FREE catalog — Lowest prices worldwide, save 40 — 60%. Systems, upgrades, parts, all major brands factory fresh and warranted. SKY VISION, 2009 Collegeway, Fergus Falls, MN 56537, 1 (800) 334-6455. CABLE TV secrets — the outlaw publication the cable companies Iried to ban. HBO, Movie Channel, Showtime, d esc ram biers, converters, etc. Sup- pliers list included. $9.95. CABLE FACTS, Box 711- R, Pataskala, OH 43062. INCREDIBLE NtONITOH BUY! THEY WON'T LAST LONG AT THESE PRICES! 9"„TTL (Open Frame) Monitors Cable TV Descramblers If you And a better deal, we'll better our deal. 'Jerrold 'Tocom 'Hamlin 'Oak 'Scientific Atlanta 'Zenith Ask about our extended warranty program. COD. Visa, M/C welcome. Free Call - Free Catalog, videoTech 800-562-6884 3702 S. Virginia St., Ste. 160-304 Reno, NV 89502. Also Available 12", (Open Frame} TTL 12V, Green Screen #6811 s 19.99 FREE CATALOG Included with your order: Call 1-B0Q-776-3700 or send order lo: AMERICAN design ccwoerrs Deft JH 120 815 Fdffwew *.1rJ We hra nwr 133 UsandhaMQa unique, barfain prKGd, composte MINI GEIGER COUNTER Defects ALL Types ol Radiafon Uses Sensitive Alpha Window Tuts Cpeates from W Batey (red bxl.} Cone with PC Bead. Pins. Tube and Inanxfons Sim of PC Boarct rit9" C6430 $59.95 4KV TRIGGER COEL Ua win any ante * 'ait -;: needs a 3 bad *KV trigger, M7O0 S1.2S EA. 100 fex $90.00 INVERTER TRANSFORMER g3 Small 4 Lsad d^sMrmer for use wlh 555 C to coiwt 1ZVDC to 2SIY tor ejtjIjV lI'jOfBSl tlfcS w.lh SOWTliic. N17Q3 $2JX> EA 1,000 tor St t 500 CDS CELL ASSOI Great projects Experiments Tnta liielr njsi__. ligfi 5 d^ereni fy&s. \\ G764 5 for $2,00 GIANT HORSESHOE XENON STROBE TUBI Livges tarMctae Tube *e I'M ever seen! Make a behEnauih slrabe En IrqHen wvfim W H*- lowttft. or um li in a nt-opfw rt a dism slrcbti 51a: z* nil x Mfl" witfe, glass tubing dia. S/16". Dpaa^s on 300VOC and can be used with our 4Ktoervieri|£ anrj ^piica- li&TS- Mcrrriiy thes sell lor lw $50 eatl tui iress are jyrpta and f*ft a ft* Chip^dos rot e«K£ peddnnarct). G7G5 $9,00 MINIMUM ORDER: SI 000 pkjs $3.00 sftcjwig artf harcjling SEND OHDERS TO: The Electronic GoUmn P O Bo< 5J03 Scofedafe. AZ S5241 PHONE OROEHS: (60a 451-7154 CIRCLE 177 ON FREE INFORMATION CARD CONSOLIDATED VOLUME 1 - TEST EQUIPMENT to y z o cc o LU -I LU o o 94 "Volume l-Test Equipment" 112 pages packed with specifications on Ihe most popular (6sl equipment like B&K, Beckman, ARL Simpson. Mercer, Soar, Goldstar and Vector-Viz. Choose from; hundreds or multimeters, oscilloscopes, frequency counters. Junction generators, power supplies 5 more. Send 55.00 check or money order, or call 1-600-543-3563 today & use your Mastercard or Visa. Consolidated Electronics, Incorporated 705 Watervllet Avenue., Dayton, Ohio 45420-2599 IKE NELSON'S OV1E VIEW SALES CABLE T.V. CONVERTERS OESCRAMBLERS REMOTES (No Illinois Sales) □ JERROLD DOAK □ SCIENTIFIC ^-HAMLIN ATLANTA D6MOS. □ LOW PRICES WARRANTY MIKE HAS 10 YRS. EXPERIENCE IN THE CABLE BUSINESS. CALL 708-766-5222 0R MOVIE VIEW SALES WRITE p '°- BOX 26 WOOD DALE, IL 60191 LET the government finance your small business. Granls'loans lo $500,000. Free recorded message: (707)449-8600. (KS1). CIRCUIT board design services: development schematic and PC6 layouts. Quick turnaround, (503) 345-4609, SKYCHASER, 980 Sherwood Place, Eugene, OR 97401, MAKE $75,000 to $250,000 yearly or more fixing IBM color monitors (and most brands). No invest- ment. Start doing it from your home. (A telephone required.) Information, USA, Canada $1.00 cash. US funds, other countries $8.00 RANDALL DIS- PLAY, Box 2168-R, Van Nuys, CA 91404 USA. VIDEO magic. Start your own business. Video security system. No wiring required. Ideal for small businesses, homes, property, marina. S950.00 gets you started. Camera only $490.00. Call: VIDEO MAGIC (516) 249-4216. K.D. VIDEO FOR ALL YOUR CABLE TV NEEDS WE SPECIALIZE IN DEALER PRICING QTY Jerrold (Type) SB-3 Jerrold (Type) Tri-Bi Scientific Atlanta SA-3 Hamlin MLD-1200 OakN-12Vari-Sync Jerrold 550 Converter Jerrold 400 DRX-3DIC (With Built in SB-3) 1 10 20 89,00 56.00 43.00 119.00 69.00 65.00 129.00 80.00 75.00 99 .00 59.00 45.00 99.00 59.00 58.00 99.00 75.00 68.00 69.00 109.00 100.00 1-800-327-3407 Call us tor prices on large quantities K.D, Video PO Box 29538. Mpls , MN 55429 PLANS AND KITS MINIATURE FM transmitters! Tracking transmitters! Voice disguisers! Bug detectors! Phone Devices! More! Available in kits or assembled! Catalog $2.00: XANDI ELECTRONICS, Box 25647, Dept. 60L Tempe. AZ 65285-5647. CATALOG: hobby/broadcasting/HAM/CB: Cable TV, transmitters, amplifiers, surveillance devices, computers, more! PAN AXIS, Box 130-F12, Para- dise. CA 95967. REMOTE CONTROL KEYCHAIN Complete w'mini-trnnsniiiter .. : »nd+5 vde RF receiver..;! Fully ns&*mWed including plans to build your.own aulo alarm . Quantity discounts a vail able I Check. Visa or M.C as VIS1TECT INC. BOX S442, SO.SAN FRAN./CA. 9TOBO ' (415) 872-0128 : ; Fax (415) 872-2635 tf**iyl rtc Check,Viaa or M.C Z4.!JO Add S 3 ehippin INVESTIGATORS, experimenters — Quality new plans. Micro and restricted devices. Free catalog. Self addressed stamped envelope required K EL- LEY SECURITY INC., Suite 90, 2531 Sawtelle Blvd.. Los Angeles, CA 90064. SURVEILLANCE transmitter kits! Four models of each; telephone, room, combination telephone/ room transmitters tune from 65 to 305 MHz. Catalog with Popular Communications and Popular Electronics book reviews of "Electronic Eaves- dropping Equipment Design," $1.00. SHEFFIELD ELECTRONICS, 7223 Stony Island Ave., Chicago, IL 60649-2806. CB Tricks II book. Power amplifier design and theo- ry, UHF CB tune ups. Send $19.95 MEDICINE MAN CB, PO Box 37, Clarksville, AR 72830. KITS — alarms, games, and test equipment. Send $1 .00 for catalog. R AKJ AB, PO Box 1 875, Apopka. FL 32704. New Laser Diodes MS LASERS Helium-Neon Laser Tubes from s 25 p i New Visible** Diode Modules FREE CATALOQ COMPLETE HELIUM-NEON CALLORWfttTETOOAYl | LASERS FROM '110°° MEREDITH INSTRUMENTS ?c He* lW.'G pni-a* AZ&S3l',':&>^3*.«B? PC/TV Interface — RGB to TV/video/ VCR. Switch- able between PC and composite video inputs. Channels 3 or 4, RF output. Complete PC card kits $59.95. PC board only $19.95 Mass. residents add 5% sales tax. INOVONICS CORP. 9 Barllett St., Dept. 36, Andover, MA 01310. DESCRAMBLING, new secret manual. Build your own descram biers for cable and subscription TV. Instructions, schematics for SSAVl, Gated Sync, Sinewave, (HBO, Cinemax, Showtime, UHF, adult) $12.95. $2.00 postage. CABLETRONICS, Box 30502R, Bethesda, MD 20824. LASER lighting entertainment systems. Create your own 3-dimensional laser light shows with these professional secrets! Detailed mechanical and elec- trical schematics, designs for any budget! $20.00. MILLENNIUM, 229 McAfee, Thousand Oaks, CA 91360. COMPUTER KITS General Technics Qua Illy Computer Systems Post Office Box 2676 Lake Ronkonkoma, NY 11779 (616) 9S1 -9473 General Technics Computer Kits include a complete line ot &flfcS, 2S6, and 386 niMiek. 'phey are designed /^— 10 offer ihc highest degree of quality £ 55^ and reliability available loday. They're also fun, easy lo build, educational, fully IBM compatible, very powrful, and at wholesale prices. All kitsarenre-Ttsiedand Include a free step by step assembly manual, software, one year warraruv and our 24 hour supporVorder phone line. Assembly is available. ask for your free catalog CAR alarm schematic with instructions, easy con- struction and installation. $6.00: HUNTER, 1802 Cook, Duncan, OK 73536. DAZER II personal protection device! Plans $8.00. Lasers! Transmitters! Detectors! More! Kits or as- sembled! Catalog $2 00. QUANTUM RESEARCH, 16645-113 Avenue, Edmonton, Alberta T5M 2X2. PEN transmitter: Sensitive micro FM transmitter, housed inside standard size pen. Latest surface mount technology. Complete kit and instruction S42.95 MIERONIC-INT., Box 5726. Sherman Oaks, CA 91413. BUILD this Pseudo car alarm-Led flasher with auto- matic disable via the ignition switch. Detailed sche- matic with educational information $2.50. LMT ELECTRONICS, Box 4268. Diamond Bar, CA 91765. UNIQUE projects. Build an infrared motion detector, ultrasonic distance meter, digital rain gauge. Com- plete plans, PCB layout. $4.00 each. Others avail- able. K. KEMP, 13772 Goldenwest St.. #549, Westminster, CA 92683. CIRCLE 70 ON FREE INFORMATION CARD ANTIQUE RADIO CLASSIFIED Free Sample! Antique Radio's , Largest Circulation Monthly. [?K®J Articles, Ads & Classifieds. 6-Month Trial: $13. 1-Yr; $24 (S36-1st Class). A.R.C, P.O. Box 802-L6, Carlisle, MA 01741 METAL project boxes - 50% off! Huge selection. Plus storage capacitors, amplifier kits, electronic parts. Free catalog. SCC, Box 551 RE, Dublin, OH 43017. AUDIO circuits - Highend designer's private files — PA, Hi-Fi. digital, studio broadcast, - free catalog - ETA INC., Box 829, Shingle Springs, CA 95682, PCB and schematic CAD software. Easy multilayer rubberband zoom pan and more. CGA EGA IBM compatibles. $195.00. NUMBER ONE SYSTEMS, 10565 Bluebird Street, Coon Rapids, MN 55433. Pay TV and Satellite est rambling NEW "■ 1991 EDITION "'NEW All nsw informal! on.. Turn-ons. bypasses, build your own. Our frest ytl HSJ6. Wireless Cable Hindbart $9.95. Build Sdleolte Sysltmis Uiwtar SGM ftiSS, Experiments *i1hVid»cyphef $12.95. Tht P.T.V. ami S.D, se- ries Volume E (basics] $14.95, V.@9$R95. Any 3/529 m 67*42. Scrambling News Monmiy $19.95- Sample S3. This month Turning on JerroW . New Wintef analog SI or call (anytime). COD's are OK.. 716-674-2066. Scrambling News. 1552 Hertel Avb., Bnflalrj, NY 14216, (716) 874 2038 REMOTE control. 20 page package gives info and schematics on encoder/decoder circuitry. $5.00. CONTINUOUS CONCEPTS, PO Box 60414, San Diego, CA 92166. CA residence add 7.25% tax. PLANS! Vehicle alarm battery backup system. Schematic, artwork, instructions, $10.95. AGK ELECTRONICS, N.K. PO Box 28123. Winnipeg, Manitoba R2G 4E9. POWERFUL single-chip FM room transmitter, size of a postage stamp, transmits to any FM radio up to one mite away. Complete kit $19.95 postpaid. HERTZ MICRODEVICES, Box 41771, LA. CA 90041. 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 the materials in, and a one- year membership in the International Performing Magicians with a plastic membership card that has your name gold-embossed. You get a one-year sub- scription to our quarterly newsletter "ITfe MAGIC!" Order now! $29.95 for each course + $3.50 postage and handling. (New York residents add applicable state and local sales lax). THE MAGIC COURSE, 500-B BiCounty Boulevard, Farmingdale, NY 11735. F.C.C. Commercial General Radiotelephone li- cense. Electronics home study. Fast, inexpensive! "Free" details. COMMAND. D-176. Box 2824, San Francisco, CA 94126. LEARN IBM PC assembly language. 80 pro- grams. Disk S5.00. Book $18.00. ZIPFAST, Box 12238, Lexington, KY 40581-2238. CONSUMER advocate. Help sources, any problem. SASE for description. HELP, Box 132, Indian Rocks, FL 34635. CABLE TV DESCRAMBLER LIQUIDATION! FREE CATALOG! Hamlin Combos S44, Oak M35B S60 (mln. 5), etc. WEST COAST ELECTRONICS For Information: 818-709-1758 Catalogs & Orders: 800-628-9656 CABLE TV EQUIPMENT Converters, Remote Controls, Descramblers, CD Players. JERROLD-OAK-SCIENTIFIC ATLANTA-HAM LIN ZENITH MANY MORE CALL TODAY! 4 Only quality products sold V Easy to use "/Satisfaction guaranteed V Knowledgeable sales staff V Most orders shipped within 24 hours CALL FOR YOUR FREE CATALOG 1-800-228-7404 MAKE THE CONNECTION WITH NU-TEK ELECTRONICS || 3114 .Balcones Wood Dr.#307 Dept298 Austin, TX. 7S759 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 $14.95 +$2.00 P&H. Rush US PO money order, cash or check to BONDED CABLE TV. CO. ■ No COD. 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. 2-1/2" SANYO TWEETER Paper cone wilh gold tone dust cap. 8 oz. magnet. 8 ohm. 1/2-ferro fluid voice coil. Power handling: 50W RMS, 70W max. Frequency re- sponse: 3K-20KHZ #RP-271-020 $1 M $1"95C f>. SUPER HORN TWEETER Original pieso tweeter made by Motorola. SPL=94dB2.83V/1M. Response: 4KHz- 27KHz. Handles ap- proximately 50 watts. #RP-270-010 «*P $5 M $4 M $3 9: [1.9) 110-79* UO-vi 2" DOME MIDRANGE Textile dome mid range made by Philips. S ohm. SPU90dB 1VW1M. 30 W RMS, 40 W max. Response: 550-5KHz, #RP-280-210 ■ $27 M M-3& $25™ 15" SUBWOOFER i Dual voice coil. 40 oz. magnet- 6 ohm imp. 100WRMS, HDWmax. Response: 20-1 2KHi Resonant frequency: 21 Hz. SPL=93dB 1YW1M. #RP-290-190 $54 s ° $49 M (1-3) f*-up> SUBWOOFER XOVER 200W RMS crossover designed specifically for use wilh dual voice coil sub woofers. 1 2 dB per octave roll-off at ISO Hz. #RP-260-220 $28™ $24" 340 E. Flrtl SI.. Dayton, Ohio 45402 Locnk t -51 3-222-0 173 FAX: 51 3-J2Z- 4S44 10" POLY WOOFER Medium duty. 60W RMS, 80 W max, 14oz. magnet Response: 25-2.5KI Iz. fs=28Hz. #RP-290-096 $18 M $16" l*-up1 TITANIUM COMPOSITE TWEETER , The advantages of boih hard and soft dome technologies. 8 ohm. Ferro fluid cooled voice coil. SPL=90dB 1W/1M 50W RMS, 70 W max. 4" round. Polydax #DTW100T125. #RP-270-047 12" CAST FRAME WOOFER _ ^ 12" vifoofer made m the USA by Eminence. Paper cone and dust cap with treated cloth surround. B0 oz. magnet. 2*1/2" vented voice coil. 8 ohm. 170W RMS, 235W max. 40-4, 5KHz response. #RP-29tM47 SPEAKER BUILDING BOOK Revised edition of David Weems' best selling book. Learn to build low cost speakers that rival the high priced models. #RP-5uO-021 % rr $16* - t5day money bach guarantee - S15.00 minimum outer- We accept Mastercard. Visa, Dfeoovvr. and C.O.D. orders. ■ 24 hour shipping ■ Shipping -Charge - UPS Chart sale * S1.00{t3,0fl minimum Charge) * Hours 6:30 am- 7:00 pm EST, Monday ■ Friday • Mail wdor custom' ers, please call Tot shipping estimate on orders exceeding 5 lb;. Foreign customers please send S5.00 U.S. lunds for cammfr*h Sing With the world's best bands! An Unlimited supply of Backgrounds from standard stereo records! Record with your voice or perform live with the backgrounds* Used En Professional Performance yet connects easily to a home component stereo. This unique product is manufactured and sold Exclusively by LT Sound - Mot sold through dealers. Call or write for a Free Brochure and Demo Record. LT Sound, DeptR L 3,7980 LT Parkway Lithonia, GA 30058 (404)482-4724 Manufactured and Sold Exclusive! v hv LT Sound fz-i:n:wi;t=i>i=tM'MMirt=n&!i*Jiu:yo'zr:i.i ZENITHS & TOCOMS SUPER Zenith (Z-TAC) converters (flashing)... $169.00, Zenith "turn-on" module... $49.00. Tocom 5503(A) & 5504 converters... $139.00. Tocom (add-on) descramtters... $79.00. Tocom (5503-VIP & 5507) "turn-on" chips.. .$49.00. CiN- EPLEX ViDEO GROUP. 1 (800) 726-4627. WANTED INVENTORS! Confused? Need help? Call IMPAC for free information package. US/Canada: 1 (800) 225-5800 (24 hours!}. 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 Shipped Immediately! REPUBLIC CABLE PRODUCTS INC. 4060 Paradise RrJ. #15 Depl. RE-90 Las Vegas, NV 89109 INVENTIONS/new products/ideas wanted: call TLCI for free information 1 (800) 468-720024 hours/ day - USA/Canada. BEST BY NAIL Rates: Box 5, Sarasota. FL 34230 BO KSIC AT ALO GSM AG AZ I N ES 50,000 * CATALOG LISTINGS! 92452GT, Allama, GA 30314. $5.95: Catalogs, Box MONEYMAKING OPPORTUNITIES "SECRETS OF THE Millionaires." Free Details. Mllligan, 204(RE) Kildeei, Soda. TX 78610. _ S330 + WEEKLY ASSEMBLING producls from home. Guaranteed! Amazing recorded message! 24 hours. (316)292-2091, Ex lens ion 132. COMPUTER BOOKS DISCOUNT computer books! Thousands of titles available. Including recent releases. Please call or write for our latest free catalog. BOOK WARE, 344 Watertown Road, Thomaston, CT 06787, 1 (800) 288-5662, (203) 283-6973. THIS A REGULAR TYPE BOLDFACE AD with a tint screen. To have your ad appear like this one, the cost is $4,15 per word. MAKE S100.00 DAILY selling money-making information and wholesale merchandise. Act Now! Free details. Write: Box 492-C, So. Orange, NJ 07079. BUY BONDS |«OrcT»USSEU.!>fMHf 5EtSW5 (.HEETOGS After you give something to your friends and family, may we suggest about 23 million other people? When you support (he Christmas Sciil Campaign® you're benefitting research and programs lhat give over 23 million American* wilh chronic twig disease Lhc one thing they want this Christmas. Hope. AMERICAN! :lung association ' Thp nrirtsEnnias S?i»l "People 1 * COLLIMATOR PEN (INFRA-RED) LASER DIODE (INFRA-RED) LASER DIODE (VISIBLE-RED) LASER DIODE (VISIBLE-RED) CO O Z O rr O LU 6 < EC 96 POWER SUPPLY UNICORN - YOUR LC. SOURCE! * Output: 2.5 mW (max.) FPHOMS • Operating Voltage: 2.2-2.5V • Wavelength: 820nm • Collimation: .18mrad (typ.) • Size: 11mm diameter STOCK # PRICE STOCK • PINS DESCRIPTION 1-24 2599 loot 1702 2708 2716 2716-1 TMS2716 24 24 24 24 24 256 x 4 1 us 1024 X 8 45ns 2043 x 8 450ns (25v) 2048 x 8 350ns (25v) 2048 X B 450ns 3.99 ; 6.49 ( 3.29 ; 3.79 ; 6.29 3.99 ; 3.79 : 3.79 : 369 3,19 ; .79 .17 .13 60 .93 .79 .60 60 .51 .03 .50 .89 .98 1.79 160 3.41 555 2.62 3.24 5.38 SB1052 $39.99 • Output: 10 mW (max.) • Current: 90-150 mA 27C16 2732 2732A-2 2732A 2732A-4 24 24 24 24 24 2048 X 6 450ns (25V-CMOS) 4096 x 8 450ns (25v) 4096x8 200ns (21V) 4096x8 250ns (21 v) 4096 X B 450ns I21v) 3.41 3.24 324 316 2.73 • Operating Voltage: 2.2-2.5V • Wavelength: 820nm STOCK * PRICE SB1053 $9.99 « Output: 5 mW (max.) • Current: 65-100 mA • Operating Voltage: 1.75-2.2V • Wavelength: 780nm STOCK # PRICE LS022 $19.99 TM52S32 24 TMS2532P 24 27C32 24 2764-20 28 2764 28 2764A-20 28 2764A 28 TMS25S4 28 27C64 28 27128-20 28 27128 28 271 28A 23 27C12B 28 27266-28 28 27256 28 27C2S8 28 27512-20 28 27S12 28 27C512 28 27C1024 32 68764 24 68766 24 4096 X 8 450ns (25v) 4096 x B 450ns (25v-One Time Programmable) 4096x8 4S0ns (25U-CMOS) 8192x3 200ns (21v) 8192x8 250ns (2I») 5.79 1.99 4.19 399 3.79 4.95 1,70 3.58 3.41 324 8192x8 20Ons (125»J 8192x8 250ns (12 5vl 8192x8 250ns (25») 8192 X 8 2S0ns (21V-CMOS) 16.384 x 8 200ns (21v) 3.99 3.79 3.29 3.13 6.79 6.45 4 19 3.96 5.79 5.50 5.09 4.84 5.79 5.50 S.79 5.50 5.29 5,03 4.79 4.55 3.41 282 5.81 3,58 4.95 16.384 x 8 250ns (21v) 16,384 x 8 250ns (21v) 16.364x8 250ns (2 1v) 32.728 X 8 200ns (12,5v) 32.768 x 8 250ns (12.5v) 4.35 4.95 4.95 4.53 4.09 • Output: 4 mW (max.) » Current: 20 mA • Operating Voltage: 2.2-3. 0V • Wavelength: SSSnm STOCK * PRICE LS3200 $129.99 32,768x8 250ns (12.5V) 65.536x8 200ns (12.5V) 66.538x8 250ns (12.SV) 65.536x8 250ns (125V-CMC 131,072x8 200ns (12 5v-CM 8192x8 450ns 8192 x 8 450ns j&pwic W I Lf CTR O10 Canoga Ave.. Unit B-8 UTSIDE CALIFORNIA: 1 CALIFORNIA: RDER BY FAX: Minimum Ord S) OS) 5 29 5,03 7 49 712 6.99 8.64 699 6.64 17.99 1709 463 641 5.98 5.98 15.38 N KS ■ Chatsworth, GA (800) 824-3432 (818) 341-8833 (818) 998-7975 et S 15.00 13.99 1 1499 1 5.29 1.24 Onl 11.96 12.82 • Input: 115/230v Imq Uf rCoi-d • Size 7" L x 654" Wx2»H • Output: +5 volts @ 3.75 amps •Output: +12 volts @ 1.5 amps • Output: -12 volts @ .4 amps STOCK # PfllCE PS1003 $19.99 E333a n 91311 (Orders ft CIRCLE 195 ON FREE INFORMATION CARD QUALITY PARTS • DISCOUNT PRICES • FAST SHIPPING mtmmamMM DIGITAL CLOCK AND APPLIANCE TIMER — .:: ! :.,,,:■.. ' " — ONE MINUTE TIMER )jgKal clock and appliance Imer removed from automatic iloclric coffee makers due o design changes. Operates H-* >n 1 20 Vac and is capable r> if turning on appliances (rawing up to 10 amps. because of the application I hey were designed or they automatically lur n otf after two hours. Some have surface blemishes. 4.2" X 2.45" X .1" deep. Seige or ivory with brown trim. CAT* MCT S6.50 each ItWDGiGEARHEAD ; MOTOR : •; uch C*T#LED-4 10f«S9 50 />l GREEnf < 00 each J CAT# LED-4G 1 Igr I9.S0 ft YCLLOW ft 00 each I ' CAT* LED-4Y 10 f« J9.S0 LED HOLDER Iwq 7: >■•■:.* holdw. CATttHLED 10fw65# 3 :PHotq;bes!stor fl 100 ohmB bn'^iHkjht. ICKohmtdailt. C ■ •-.&2- cz X .Ofl'high. 0.1 JJ" long leAdt. CATK-PRE-T 2ic*S1 00 100 lor 545 00 - 1000 f« S400 00 OPTO SENSOR!! Standard U-»f>d JjUP stoned optical tMtch ■ ri 1 WDMr'iB'^ipbfllWMn p| I' ad«o 7j" mounting zor.birz CAT#OSU-7 2lorS1.00 HEFLECTIVEOPTO SENSORS ThujBO unitfi hava an IRemittw and tentx p«r pointing in the Mm* direction. Light from *rniHer bounce* oH object to b* detected by lor.ior Efffl^vfl-r-uigs appro* 0.15V TTvee type* tvftitable. TRW/ Optron f OPB8447-3 FUcta.n-guJu' w/ 2 S" wire Ivade CAT#OSfl-4 2 lor St .00 tfT^fca TRWl Optron Jf OPB703A Wedg* th Bp* '.■.-.:;■. PC pint. CAT* OSR-3. TH "ch THW^Optfonff OPa7l1 j^^l Rfldangijar WtTt with PC pine. CATlrOSR-2 75f Mot. '" LEO, FLASHHR KIT:: Two L ED'S Hash in unison whren a 9 voU battery is attached. This kit includes a p.c. board, all the part* and instructions to maks a simple flasher circuit. A quick and easy prefect lor any- one wilh basic seta's ring skills. CAT*! LEDKIT $1 75 per kit !LED CHASER KIT:: Build this vanable speed ledcheser. lOWsftaflh sequentially at whatever speed you set them for. Easy to build kii includes po board, parts and instructions. Ideal for special lighting effects, costumes, etc. Operates on 3 to 9 volts PC board is 5" X 2 25" A great one hour project. CAT* AEC S&SOeach STEPPING MOTOR CONTROLLER KIT Lsarn about Stepping motors white building the simple circuit. Includes circuit board, motor and all □arts except 12 Vdc power supply. CAT#SMKiT S1B,00each electroluminescent strip(OLow stripj;; an din verier;;; oik Used lor backighting control panels oi as decorative or emergency prime Ighling source. Tnin, tovgh And ' o>r'-.. tney oper- ate on low current AC voltage. The pro- lerred power source is a. miniature DC to AC inverter, These nave a bit of an odd shape. The strips are 2. IS" wide X J3 9 ft" Long and are 02S" thick. The luminescent area is 5.3" long X 1.72" wide and hn one comer cut off, leaving a useful area ot fairly good proportions. We are selling the strips end In* vertere as a package. Inverter operates on G Vdc. Glow atrip, invefler and hook-up diagram CAT* GS-SQO $5 00per»t EXTRA INVERTERS I nput: 6 Vdc Output : 225 Vac CAT0INV-1 $2.00 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 Disccvercard • California, Add Sales Tax • Shipping And Handling $3. SO For the 48 Continental United States ■ All Others Including Alaska, Hawaii, P.R. And Canada Must Pay Full Shipping • Quantities Limited • No C.O.D. • Prices Subject to change without notice. m MAIL ORDERS TO: ALL ELECTRONICS CORP • P.O. BOX 567 • VAN NUYS, CA 91408 CIRCLE 107 ON FREE INFORMATION CARD □ m O m S m 31 fJQ to o 97 J AMECO GoldStar 20MHz Oscilloscope S j^ss 24 Hour Order Hotlin (415)592-8097 Features: * 6" rectangular CRT dispEay. internal gratitude & Scale ■ Phase difference measurements beiween two lorms under two methods: x-y scope and Dual Trace * Two dilferent scats probes : k1 and k 10 ■ Bandwidth Iron DC to 20MHz * Includes; Two 40MH2 probes, two loses, power cord, operation manual, schematics and block and wiring diagram * High sensitivity: imV/div * Two Year Warranty Jameco Logic Pulser ■ Compatible with TIL DTL RTL HTL, HNIL. MOS and CMOS iCs. - 1 Mil Sync input impedance * "One shot" or continuous SHz train pulse ■ Pulse repetition rale: O.5pps400pps. * Pulse width output at 1QQma load: 10us * Pul$er mode output curreni: 10mA ■ Square wave current outpus: 5mA * Audible tone * Siie:7.75"LK l"Wx.625"H. LP540 $16.95 Jameco Logic Probe - Mas Frequency 8GMH* * Minimum delectable putee: ions >i£0Kii mpui impedance * Max. suppty voltage- '25V 1 * TTL HhreshokJ: (Lo)*0 SV dV (Hi) *2.3v -Q.2V ■ CMOS IhreshoW: (Lo) 30% VCC 10% (Hi) 70%VCC -10% MS104 $24.95 Metex Digital Multimeters General Specs: * Handheld, high accuracy ■ AC DC voftage. AC' DC current, resistance, diodes., continuity . Iran&islorhFE * Mpnual ranging w overload proieclion M3650 4 M46S0 only; * Aim measure Irequency and capacitance PROTOTYPING PRODUCTS M4650 only: - Data hold switch • 4.5 dtgil Jameco Solderless Breadboards M3G10 3 5 Dflit Multimeter 559.95 _^^J* M3650 3 5 Cwgit Multimeter tt Frequency 5 ^^^^^\ Capacitance .»„♦. ,«,»»... S74.95 \ ^^^. M4650 J 5 Digit ft Frequency. Capaetence \ ^^^\ and Daia hold Switch., $99,95 V"*^ V^^ Handheld Multimeter .IF97 3.5 diQ'l LCD with automatic polarity indicalion * AC DC voltage measurement up to 500 volts ■ AC DC curreni measuremeni up to 200mA * Resistance measuremeni up lo 2QMil - Conitnuity checker wiih audible lone • Diode and logic tester * Auto 'manual range and data hold Junctions - AN range protection and Junction indications DMM905 S49.95 Pirl Dim. Coniacl Binding No. L" I W" Points Posls Price JE21 325 i 2 125 400 $4.95 JE23 6.5 « 2 125 830 56.95 JE24 65« 3 125 i 360 2 $12.95 JE25 6 5 « i 35 1.660 3 $17,95 JE26 6 875 j 5.75 2.390 2 $22.95 JE27 imi* 3.220 J $32.95 Jameco Universal IC 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 JE680 uses the JEDEC standard lor logic devices. Accepts input from virtually all major software packages including: PALASM. PLAN, CPUL, ABEL, and AMAZE .$1799.95 • Programs all current EPROMs in the 2716 lo 27512 range plus the X2864 EEPROM •RS232 port • Soltware included EPP ....$199.95 UVP EPROM Eraser r - Erases all EPROM's ■ Erases 1 chip in 15 minutes and 8 chips in 21 min • UV intensity: 6800 UW/CM 2 DE4 $79.95 Prototype Design Stations Features: - Removable solderless breadboard - Variable and fixed DC power supply • Multi- frequency signal generator • Analog multimeter - 8 bicolor LEDs (red & green) • 8 logic switches - Logic probe • Lighted power switch ■ Fuse overload protected ■ Pulse Generator • Binary coded decimal (BCD) to 7-segment decoder/ driver ■ DB25 connector • Frequency counter (1 Hz to 1 MHz) • Sturdy ruggedized case WM2 $299.95 Soldering and Desoldering Stations 60 Watt Analog Display Soldering Station • Electronic temperature control from 200= to 878"'F ■ Cartridge heat- ing elemeni for a longer lite of the soldering tip XY1683 $69.95 30 Watt Electronic Temperature Controlled Desoldering Station ■ Electronic temperature control from 212" to 842 ! F • Self contained high rotary vacuum pump XY999 $299.95 CIRCLE 114 ON FREE INFORMATION CARD OuaWN i**** Cate\o9 J AMECO £\eC yoV^ c jv\e^ s t ptoa^ cx l 'art No. 4LSO0 4LS02 '4LS03 Integrat 1-9 10+ .25 .15 .25 .15 .25 .15 .25 .15 .28 .18 .59 .49 ,59 .49 .28 .18 .25 .15 .29 .19 .35 .25 .49 .39 .28 .18 .29 .19 .35 .25 .28 .18 .28 ,18 .35 ,25 .49 .39 ,85 .75 .85 .75 .39 .29 .55 .45 .49 .39 .49 .39 ed Circuits Part No. 74LS154 74LS155 74LS156 74LS157 74LS158 74LS166 74LS169 74LS173 74 LSI 75 74LS181 74LS189 74LS190 74LS191 74LS193 74LS194 1-9 1.29 .49 .49 .45 .39 .79 .99 .49 .39 1.39 3.95 .59 .59 .69 G9 10+ 1.19 .39 .39 .35 .29 .69 .89 .39 .29 1.29 3.85 .49 .49 .59 59 Mi Value 43PXX 63PXX PN2222 PN2907 f M4004 2N2222J JMT123 206-8 MPC121 MS102 DB25P DB25S XC209P XC556C scellaneous Components Potentiometers s available (insert ohms into space marked ' SOOSi. IK, 5K, 10K, 20K. 50K, 100K. tMEG XX"): ,,,.99 ....89 4LS04 '4LS05 4LS06 4LS07 4LS08 '4LS10 Transistors 12 1N473; 12 I 2N390' .....10 ; 1N751 ^ 25 i C106B Swi SPOT. On-On (To- SPST, 16-pin (DIP SPDT.On-Otf-OnfT SPST, Momentary D-Sub Conne Male. 25- pin .65 Female. 25 -pin.... 75 L Tl.(Red) 14 T! a «. (Greeni ...16 And Diodes i 25 2N4401... 1 12 1N4148... 15 2N3055... 1 49 MN270 ches ....15 07 ... .69 ?5 . 1.25 '4LS1 1 I .1.09 '4LS13 '4LS14 '4LS20 '4LS21 4LS27 '4LS30 '4LS32 '4LS38 '4LS42 '4LS47 '4LS48 (Push-Bulton} Dtors and Hoods DB25H Hood .1.19 ,39 74LS221 74LS240 74LS241 74LS323 74LS541 74LS590 74LS670 74LS688 81LS95 81LS97 .69 .59 .59 2.49 1.09 5.95 .89 2.19 .99 .99 .59 .49 ,49 2.25 ,99 5.75 .79 1.95 .89 .89 EDs XC556R T1 3/4. (Red) 12 XC556Y T1 3 /4. (Yellow) ...16 IC Sockets Low Profile Wire Wrap (Gold) Level #2 8LP 1 1 8WW .49 14LP 12 14WW 65 '4LS112 '4LS122 '4LS123 '4LS125 16LP 13 24LP ....19 28LP 22 40LP 28 Soldenail Standard & Head 16WW .....69 24WW 28WW 40WW ir Plug Sockets Also Av .1.05 ..1.29 ..1.79 liable- Assemble Your own Computer Kit! Jameco 16MHz 80386SX Desktop Computer Kit ■ Building your own computer provides you with a better understanding of components and their functions ■ In-depth assembly instructions included ■ Have your new computer assembled and running in three hours, using common tools ■ Software included ■ Purchase computer kits configured by Jameco or design your own Jameco 16MHz 80386SX Desktop Computer Kit Includes: • 80386SX Motherboard with 2MB RAM (expandable to 8MB) • 1 01 -key enhanced keyboard • Mulli I/O Card • Toshiba 1.44MB. 3.5" DSHD floppy disk drive ■ Baby si2ed desktop case • 200 Watt power supply ■ DR DOS (Version 5,0) by Digital Research and Diagsoft's QAPIus diagnostic software $1199.95 JE3816 ■ Hard Drives Conner (16-bit IDE) CP3044 10MB 3 5" Low Prolple $469.95 CP31 84 8MB 3.5'HH... $699.95 CP3104 1MMB 3.5 - HH... $799.95 ADP20 Hosi Afliaprer... ..$29.95 Relisys 14" VGA Color Monitor • Max resolution: 720 x 480 ■ Bandwidth: 30MHz « Tilt/Swivel base RE9513 $449.95 Jameco 16-bit VGA Card • Supports VGA, EGA. CGA. MDA and Hercules modes ■ Comes with 256KB uideo RAM upgradable to 512KB (eight 41464-80) • Capable of B40 x 4S0 with 256 colors. BOO x 600 with 16 colors VG2000 $149.95 24 Hour Order Hotline (415)592-8097 Look to Jameco. • Wide selection of integrated circuits and components ■ Quality prototype and test equipment Additional items that Jameco offers; ■ Hard Drives • Motherboards - Memory Modules: • SIPPs • SIMMs ■ NEC V20 and NEC V30 Chips . RAMa ■ Math Coprocessors • Computer Kits • Integrated Circuits • Components ■ Much, much more ! Let us show you what we have to otter; catt or write tor the iatest Jameco catalog! 24 Hour Order Hotline (41 5) 592-8097 FAX'S: (415) 592-2503 or (415) 595-2664 Telex 176043 1355Shoreway Road Belmont, CA 94002 $50.00 Minimum Order Data Sheets - 50c each Far a FREE 90-Page catalog send $2.00 to cover tirsl Class Postage and Handling 1990 Jameco Eleciranics IZ'SKl CA Residents Add 6.25%, 6.75% or 7.25% Sales Tax Shipping - Add 5% plus St. 50 Insurartce i May va*y according ;o weigm and snipping memod) Terms; Prices subject to change wilhoul nolice. li ems subject lo availability and prior sale. CdftipleLa iisi -of [EH1- ELECTRONIC HYPNOTISM TECHNiOJES . . .SSflO 2 EML1 - LOWER POWERED COIL GUN LAUNCHER S5.00 3JL3- JACOB LAODER 3 MODELS . 510.00 SDS- SEEINTHEDARK $10.00 Q-LEV1- LEVITATI OK DEVICE . . $10.00 Ufr-MVIK -3 MILE FM VOICE TRANSMITTER $3450 3 PF S1 K - WW CONTROLLED- PLASMA FIRE SABE R $4950 5 NIGTK - HI FLUX NEGATIVE ION GENERATOR $3450 £«PG5K- PLASMA LIGHTNING GLOBE $4950 = | IHC2K- VISIBLE SIMULATED 3 COLOR LASER .. .$4450 g= H0D1K- HOMING/TRACKING BEEPER TRANSMITTER $44.50 gff IBUHC— 25 MW HAND-HELD VISIBLE LASER GUN $24950 3 £ BTC3K - 250,000 VOLT TABLE TOP TESLA COIL . . . $249.50 CO I0GZK — ION RAy GJN , praiect erierjy without wires $129.96 r— TK E1 K - TELEffll E TIC E NHANCE WELECTRIC MAN . . SMO 2 VWPM7K - 3 MILE AUTO TELEPHONE TRANSMITTE R . $4950 q ASSEMBLED IN OUH LABS Uj LIST10 - INFINITY XMTR Lislen in via phone lines . S199.50 J IPG70 — INVISIBLE PAIN FIELD BLASTWAVEGENEHAT0RS74.rJ0 DO ITM10 - 100,000 VOLT INTIMIDATDR UP TO 20' $99.50 S TAT30- AUTOMATIC TELEPHONE RECOROlNGDLvlCE 524.50 UJ PSP40 - PHASOR SON IC BLAST WAVE PISTOL . , . $89.50 M MEW— AU.NEW 28" VWB COLORED NEON STICK ,574.50 CO LGU2Q - 5 TO 1 MW VISIBLE REO HeNe LASER GUN 519*50 ^BLS10- 100JX) V*ATT BLASTER DEFENSE WAND . $8950 EASY 0RDEH1NG PROCEDURE - TOLL FREE 1-BD0-22 1-1705 or 24 HRS ON 1-H&673-4730 or FAX IT TO t-603-672-5406 VISA. MC. CHECK, MO IN US FUNDS. INCLUDE 10% SHIPPING. ORDERS 5100.008 UPONLY AOD $10.00. CATALOG $1.00 OR FREE WITH ORDER. INFORMATION UNLIMITED P.O. BOX 716, DEPT. R2, AMHERST. NH 03031 CO o O X F o LU ~J UJ g < EC 100 COMPUTERS FOR LE$$ JCI 10 MHz 8088 System $399.00 • 10 MHz Motherboard w/WOKB RAM • Math Co-Processor Socket • One 5.25" 3«0 KB Floppy A Controller • 101-Key Enhanced Keyboard • lSOWatlPowerSupplyJtCase • MonoGraphica Card w/ Parallel Port • 12? Amber Monochrome Monitor JCI Standard Configuration: 1 MB RAM on board ©Wait Stale Built-in Real Time Clock & Calendar Math Co-Processor Socket One 1.2 MB or 1.44 MB Floppy Drive 1:1 Hard I Floppy Disk Controller 2 Serial, J Parallel, and 1 Game Port 101-Key Enhanced Keyboard Deluxe Case w/ 200 Watt Power Supply MonoGrapbks Card w/ Parallel Port 12" Amber Monochrome Monitor JC1 12 MHz 80286 System $ 649.00 JC1 16 MHz 386SX System $ 869.00 JCI 20 MHz 80386 System $1149.00 JCI 25 MHz 386 32K Cache $ 1495.00 JCI 33 MHz 386 32K Cache $ 1850.00 Please Call For Custom Configurations One Year Parts & Labor Warranty 30 Day Satisfaction Guarantee Shipping & Handling Extra VISA & WC add 3% Amex add 4% JINCO COMPUTERS INC. 5122 Walnut Grove Avenue San Gabriel, CA 91776 Tel: (81 8) 309-1 1 08 - Fax: (81 8) 309-1 1 07 ADVERTISING INDEX RADIO-ELECTRONICS does not assume any responsibility for errors that may appear in the index below. Free Information Number imt 75 1 07 1 93 77 67 ys 1 09 70 187 1 76 184 55 58 188 1% 127 198 177 121 189 86 185 114 104 178 53 93 61 186 56 197 179 Page AMC Sales „y Ace Products 62 All Electronics 97 Alpha Products , 75 Amazing Concepts 1 IK) li&K Precision CV4 Banner Technical Books 90 Beckman Industrial 14 C&S Sales 5 CE1 94 l. i Hi .... , , , , , , . 1 1 . ^j Chenesko Products 62 Command Productions 89 Communications Specialists 79 CompuServe CV3 Contact East 2K Cook's Institute ii I D&D Electronics 77 Damark International 17 Datak Corporation 28 Deco Industries 62 EKI 37 Electronic Goldmine 94 Electronics & Engineers B.C. . . .82 Fluke Manufacturing CV2 Global Specialties 12 Grantham College 56 Heathkil 29 How to Book Club 7 ISCET 81 Jameco 98,99 Jan Crystals 89 Jinco Computers 100 King Wholesale 92 Lindsay Publications 73 Ml) Electronics. 92 Mark V. Electronics. 93 Microprocessors llnlld 87 NK1 Schools 18 Optoelectronics 39 Parts Express 95 Pholronics, Inc 62 Probemaster ..31 78 Radio Shack 32 190.191 SCO Electronics 72 194 Sencore 27 — Star Circuits 31 192 TECI 79 123,180 Test Probes 3 225-228 Test Probes 3 195 Unicorn 96 181 Viejo Publications 90 182 WIT Publications 79 183 Xandi Electronics 62 ADVERTISING SALES OFFICE Gemsback Publications, Inc. 500-B Bi-County Blvd. Farmingdale, NY 11735 1(516) 293-3000 President: Larry Steek let- Vice President: Cathy Steekler For Advertising ONLY 516-293-3000 Fax 1-516-293-3115 Larry Steckler publisher Arline Fishman advertising director Denise Haven advertising assistant Christina Estrada advertising associate Kelly McQuade credit manager Subscriber Customer Service 1-800-288-0652 Order Entry for New Subscribers 1-800-999-7139 7:00 AM - 6:00 PM M-F MST SALES OFFICES EAST/SOUTHEAST Stanley Levitan, Eastern Sales Manager Radio-Electronics 259-23 57th Avenue Little Neck, NY 11362 1-718-428-6037, 1-516-293-3000 Fax 1-718-225-8594 M I D WE ST/Texas/ Arka ns a s/O kla . Ralph Bergen, Midwest Sales Manager Radio-Electronics 540 Frontage Road— Suite 339 Northfield, IL 60093 1-708-446-1444 Fax 1-708-446-8451 PACIFIC COAST/ Mountain States Marvin Green, Pacific Sales Manager Radio-Electronics 5430 Van Nuys Blvd. Suite 316 Van Nuys.CA 91401 1-818-986-2001 Fax 1-818-986-2009 CIRCLE 178 ON FREE INFORMATION CARD There's nothing newabout having everything ^- Oft f o /. o you need inoneplace. ■ > -=» ^- 'T* -. ■^r^-'" J - = , 1 ' WithCompuServe, it's all at your fingertips. When you become a member of CompuServe, you join a vital, active community of over 500,000 friends and neighbors from all over the world. Small-town friendly We keep in touch with electronic mail and faxes, and by posting messages on our bulletin boards. We even meet in forums to discuss everything from science fiction to sharing software, and to get invaluable personal computer software and hardware support. And that's one of the best things about small towns: people helping people. Big-city opportunities, But we can also shop coast-to-coast at hundreds of nationally known stores, and take advantage of a world-class library We have access to the latest national and interna- tional news, And our special financial files offer complete statistics on over 10,000 NYSE, AMEX, and OTC securities. We can even trade online with our local discount brokers. And, just for fun . . . We ve also got games — everything from trivia to TV-style game shows with CIRCLE 184 ON FREE INFORMATION CARD live entertainment to interactive space and fantasy adventures, We've got airline schedules, so you can check out the bargains and book your own flights online. We even have listings from over 35,000 hotels. It's not hard to get here, To get to CompuServe, all you need is a computer and a modem, We'll send you everything else, includ- ing a $25.00 Usage Credit. In most places you'll be able to go online with a local phone call. To buy a CompuServe Mem- bership Kit, see your nearest computer dealer, To receive our informative brochure or to order direct, call 800 848-8199. CompuServe Notice any difference between these two DC power sources? - __ K -PRECIS ^n — fl J ftrdl !■]■■ ™"T ... 1 \ r| MM IMI | ,— -*-. - - ' ' '( HIGH-F'RI H+H frr H++ hh mt+m tttt m+ Htt ^ C Your budget sure will! B&K-PRECISION power supplies cost less than other power supplies you may be used to buying, but to your circuits they look identical. Your circuit will see only the same pure, clean DC power that comes From the high-priced lines. You'll see the savings. B&K-PRECISION builds DC power supplies for most bench appli- cations requiring up to 10 amps. All are fully regulated with excel- lent ripple and noise characteristics. Some models feature digital metering, multiple outputs, tracking and constant current operation. Start saving cash on your next power supply purchase. Compare features, performance and price and you'll choose B&K-PRECISION. For a free Power Supply Selection Guide or immediate delivery, contact your local distributor or B&K-PRECISION, Front row left to right: Model 1660 $629, Model 1610 $215, Model 1630 $315, Model 1635 $365. Back row top; Model 1601 $485, Model 1646 $489; Bottom: Mod# 16"Sb,$510. CIRCLE 77 ON FREE INFORMATION CARD M AXTEC INTERNATIONAL CORP. Domestic and International Sales B47D W. Cortland St., Chicago, IL 60635 312-889-1448 • FAX: 312-794-9740 Canadian Sales, Atlas Electronics, Ontario