BUILD YOUR OWN VIDEO TELEPHONE! {}'. 46783 I ECHNOLOGY - VIDEO - STEREO - COMPUTERS - SERVICE UILD R-E's IDEO TELEPHONE 4 dd a new dimension to youi ihonc conversations with 01 lasy-to-build ligh-resolution circuit! URN YOUR PC INTO A REQUENCY COUNTER Jniversal counter board uns under windows UILD R-E'S AUDIO WEEP/MARKER GENERATOR ^ must for testing audio mplifier and filter ircuit performance EMICONDUCTOR IEMORIES ^n examination of today; ;echnology and a jeek at tomorrow's ERROELECTRIC DEVICES slew advances deliver better ion-volatile memories c F u ,;.- : ' C LEV • • • •* * • ■ U 1 -.'■ 3k a "09128"48783 l 03 $2.95 U.S. $3.75 CAN flNSBACK 87 75Q456HRR516TO3 03 SEP 91 Rl FLUKE AND PHILIPS - THE GLOBAL ALLIANCE IN TEST & MEASUREMENT FLUKI PHILIPS PHILIPS Great Choice. More professionals in more industries make Fluke their first choice in multimeters. Fluke DMMs. Reliable. Accurate. Powerful. Tough. Versatile. Easy to use and simple to operate. Backed by the longest, most comprehensive warranty in the business. Made in the U.S.A . In short, Fluke makes meters you can bet your reputation on. More choice. No matter what the job, there's a Fluke to handle it. There's the new 80 Series — the most powerful, most complete test and measurement system available in a handheld package. The popular 70 Series-simply put, the most requested DMM in the world, with nearly 2 million units in service since 1984. And the Fluke 21 and 23-70 Series simplicity in high-visibility yellow. The Fluke 25 and 27— the most rugged meters ever built, totally sealed against water, dust and other contaminants. And the precise 8060 Series-with the versatility of a test lab, the accuracy of a bench instrument, and the convenience of a handheld. Smart choice. Compare Fluke DMMs with any other handheld. No one else gives you as much meter for your money. And no other meter costs less to own. CIRCLE 121 ON FREE INFORMATION CARD Your choice. For the name of your nearest Fluke distributor, call toll-free 1-800-44-FLUKE, erf. 33. And make a great choice. John Fluks Wig. Co.. Inc. P.O. Bo* C9C90 MS ?50C Emit, WA 98206. U.S.: (206) 356-5400 Canada: (416) 89O76O0. Older Countries: (206) 3SB-S500. " 19)9 Jotin Fluke Mlg. Co.. Inc. All fishls reserved. Ad No. 0491-F70 FROM THE WORLD LEADER IN DIGITAL MULTIMETERS March 1991 Ectrcmcs Vol. 62 No. 3 33 BUILD THIS VIDEO PHONE Send and receive video pictures over standard phone lines! Charles Colby 43 TURN YOUR PC INTO A UNIVERSAL FREQUENCY COUNTER Build a frequency-counter/timer board that works with windows. Joe Grasty and Bill Schulz 55 AUDIO SWEEP/MARKER GENERATOR Display the frequency response of your amplifier or filter design, John Wannamaker I erroetectrfc tC's- / chips thot remember PAGE 63 63 FERROELECTRIC IC'S: CHIPS THAT REMEMBER Will they make lost data a thing of the past? TJ Byers 68 SEMICONDUCTOR MEMORIES A look at memory technology, now and in the future. Stephen J. Bigelow AliDiO SWEEP MARKER GENERATOR '■'■-* :**; 6 VIDEO NEWS What's new in this fast- changing field. David Lachenbruch 22 EQUIPMENT REPORTS Fluke Model 45 Dual-Display Digital Multimeter 74 AUDIO UPDATE Transfer functions revisited. Larry Klein 77 DRAWING BOARD Build a 5-volt, 5-amp power supply for your test bench. Robert Grossblatt 84 COMPUTER CONNECTIONS Making connections. Jeff Holtzman 98 Advertising and Sales Offices 98 Advertising Index 12 Ask RE 16 Letters 87 Market Center 24 New Products 4 What's News 52A R-E Shopper* i CO "Included in selected issues only. w o z o cc h- o LU I w < o o < UU1LD VOUR OWN VIDEO TELEPHONE! tonics It's been more than half a century since the picture phone made its de- but at the 1939 World's Fair. It was a big idea, with a price tag and equip- ment sized to match. Now there's an IC that greatly reduces the cost and size of a video-phone system. Our version of the video phone, or video modem, transmits and receives high-resolution, still-video frames. It consists of abase unit that we show connected to a small CCD camera module and to a Sony Watchman; a standard video camera or cam- corder and a monitor will work just as well. You can send or receive im- ages anywhere in the world, as long as the person at the other end has a video phone too. Turn to page 33 to find out how to make a couple of video phones — or get a friend to build the second! m—msi,nnn MzteEtrunics Hugo Gflmsbaek (1884-1967) founder Larry Stickler, EHF. GET. editor- in-chief and publisher EDITORIAL DEPARTMENT Brian C, Fen ton* editor Marc Spiwak, associate editor Kim Dunleavy, assistant technical editor Tori Scaduto, assistant editor Jeffrey K. Moltzmart computer editor Robert Grossblatt, circuits editor Larry Klein, audio editor David Laehenbruch contributing editor Don Lancaster contributing editor Richard D. Fitch contributing editor Kathy Terenzi, editorial assistant ART DEPARTMENT Andre Duzant, art director Injae Lee. illustrator Russell C. Truelson. illustrator COMING NEXT MONTH PRODUCTION DEPARTMENT Ruby M. Yee, production director Janice Box, editorial production Karen S. Tucker advertising production Mnrcella Amoroso production assistant THE APRIL ISSUE GOES ON SALE MARCH 1. BUILD AN ELF MONITOR Measure your exposure to potentially hazardous extremely-iow-frequency (60-Hz) magnetic fields. FCC APPROVES NO-CODE HAM LICENSE Docket 90-55 approved for Technician-Class no-code license. EXPERIMENTS IN VOICE RECOGNITION Put the VCP200 IC to use in an assortment of projects. BUILD A ROBOT Learn about microcontrollers, obstacle avoidance, and stepper-motor control by building this 8748-based robot. BUILD A 40 WATT POWER INVERTER It converts 12 volts DC to 120 volts AC. CIRCULATION DEPARTMENT Jacqueline P. Cheeseboro circulation director Wendy Alanko circulation analyst Theresa Lombardo circulation assistant Michel e Torrillo, reprint bookstore Typography by Mates Graphics Cover photo by Diversified Photo Services Radio-Electronics is indexed in Applied Science S Technology Index arid Readers Guide to Periodical Liter- ature. Microfilm t, Microfiche editions are available. Contact circulation depart- ment tor details. Advertising Sales Offices listed on page 98. Radio-Electronics Executive and Administrative Offices 1 516-293-3000. Subscriber Customer Service: 18002880652. Order Entry tor New Subscribers: 1 800999 7139. As a service to readers, RADIO-ELECTRONICS publishes available pFans or information renting to newsworthy products, techniques and scientific end technological developments. Because of possible variances, in the quality and condition of materials and workmanship used by readers. RADJO-ELECTROMICS disclaims any responsibility for the safe and proper functioning of reader-built projects based upon or from plans or information published in (his magazine. Since some of the equipment and circuitry described in RADIO- ELECTRONICS may relate to or be covered by U.S. patents, RADIO- ELECTRO NIGS disclaims any liability for the infringement of such patents by the making, using, or selling of any such equipment or circuitry, and suggests that ariyone interested in such projects consult a patent attorney. RADIO-ELECTRONICS, (ISSN 0033 76623 March 1991. Published monthly by Gemsback Publications. Inc., 500 B BiCounty Boulevard, Farmingdale* NY 1 1735 Second-Class Postage paid at Farmingdale, NV and additional mailing offices. Second-Class mail registration No. 9242 authorized at Toronto, Canada. One-year subscription rate U.S.A. and possessions $17-97, Canada $23,97, all other countries $26.97. All subscription orders payable in U.S.A. funds only, via international postal money order or check drawn on a U.S.A. bank. Single copies $2.95. <- 1991 by Gem shack Publications. Inc. All rights reserved, Printed in U.S.A. POSTMASTER: Please send address changes to RADIO ELECTRONICS. Subscription Dept.. Box 56115. Boulder. CO B0321-5115. A stamped self -addressed envelope must accompany all submitted manuscripts and/or artworkor 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. A"\ Ai ""' L QA'O V W Bureau V&-^JY Ol Orculalion ^§^r Talking Multimeter. Press a but- ton on the probe and Shis meter calls out the reading while display- ing it on a high-contrast LC display. Full auto-ranging, continuity sounder, diode -check mode. Low- battery and over -range indicators. #22-164 99.95 "HOTLINE" SPECIAL-ORDER SERVICE Your nearby Radio Shack stocks over 1000 popular electronic parts and can special-order many items from our main warehouse — ICs, tubes, semiconduc- tors, phono cartridges and styii, even SAMS' manuals. We can also supply replacement batteries for cordless phones, computer memory, transceivers, pagers and more. Service is fast and there is no postage charge. (1) Universal Breadboard. Our best! Molded 2Vi x 6'fe" board on 7 x 4" steel base with rubber teet and three binding posts. #276-169 19.95 (2) Breadboard Jumper Wire Kit. Our 140-piece set of ready-to-use hookup wires. #276-173 4.95 (1) High-Speed 12VDC Motor, Up to 15,200 RPM at no load. About 2" long (with shaft). #273-255 . . 2.99 (2) 12VDC Brushless Micro Fan. For cooling mobile equipment and hum -sensitive circuits. Rated 4.6 CFM 150 mA. #273-244 . . . 17 95 N rt) A m [3) [4) | (1) Adjustable Project Holder. Our extra-sturdy "Helping Hands" holder sim- plifies soldering, gluing and assembly work. #64-2093 B.19 (2) Duat-Wattage Soldering Iron. Go from 15 to 30 watts with the flick of a switch. 8VV long. UL listed AC. #64-2055 9.49 (3> Lead -Free Solder. Top choice for fine electronics work. 96% tin, 4% silver composition. .032 "-diameter. 0.25 oz. #64-025 1.99 (4) Soldering Paste Flux, #64-021 1.79 dl Computer/ Business Machine AC Power Cords. 6 ft. HP (CEE-type) connectors. UL listed. (1) Extension. #278-1259 . . 4.99 (2) 90" Type. #278-1260 5.99 (3) With Straight CEE Connector. #276-1257 3.99 (1) (1) Hi-Precision Thermistor. Low- cost, high-quality temperature sen- sor. #271-110, 1.99 (2) 15-Turn Trim, mer Pots. 3 /j- watt. 1k, #271-342. 10k, #271-343. 20k, #271-340.Ea,1.49 r Infrared Module. Ready-to-use module for remote- control projects. Combines an IR detector, limiter and demodulator in a compact 3- lead package. 5VDC. With data, #276-137 . . . 3.49 EWBCEll. UfiTTERY GU1QEDOOK ENERCELL' Bat- tery Guide. Com- plete data on all ENERCELL batter- ies plus basic bat- tery information and tips to help you choose the right battery for the job. Over 230 pages. #62-1304 ..5.95 Mini Audio Am- plifier. Perfect for use as a test- bench amp and for computer voice/ music syn- thesis. Built-in speaker plus Va" headphone jack, Vs" input jack, vol- ume control. #277-1008, 11,95 <•> ' (2) (3) (1) Stackable Ba- nana Plugs. Jack for "chain" hook- up. One red and one black. #274-734, Set 1.59 (2) Package of 10 Jumper Leads. 14" long. Mini 'ga- tor clips. #278-1156 ..3.99 (3) Ail-Metal Grounding Post. Accepts banana plug or wire. #274-667 . . . 99C (4) Coiled 6-Ft. Banana Plug Test #278-750, Pr/4. 99 (5) 4-ConduCtor Double-Shielded Cable. 30 feet. #278-777 . 7.95 Miniature Piezo Speaker. Only 1 31 te" -diameter by %«" thin. Efficient 1200-ohm audio transducer can be directly driven by ICs. Response: 500 Hz to 20 kHz. 273-091 2.49 Modular Balun. BNC male connec- tor to standard modular phone jack. Lets you use phone cable in place of more costly shielded ca- ble in computer network hookups. #276-1410 ..16.95 Crimp-Style D- Sub Connectors. With quality gold- plated contacts. 9- Position Male. #276-1427 . . . 99C 9-Pos, Female. #276-1428 . . . 1.19 25-Positlon Male. #276-1429 ... 1.49 25-Pos. Female. #276-1430 . . 2.49 D-Sub Pin Crimp- ing Tool. This pro- fessional steel tool makes it easy to in- stall D-sub connec- tors. Accepts #20, #24 and #28 pins. Comfortable cush- ioned handles pro- vide a firm, secure grip. S'Ib" long. #276-1595 ..9,95 lllllllllll (31 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 appty at participating RMio Snack stores and dealers. Radip Shack is a division oi Tandy Corporation (1) Grid Boards. Solder-ringed holes with DIP IC spacing. Indexed for easy pin-out identification. 4'/2x65/a': 2200 holes. #276-147 ... 3.79 2% x 33fc". 750 holes. #276-158 . . . 2.29 1"tex2"/ji". 356 holes. #276-149 ... 99 C (2) 44-Position Plug-In Board. The perfect foun- dation for many projects. With Vie" grids. 4'fex4" #276-154 . . . 3.49 (3) 44-Position Card -Edge Con- nector. For plug- in board. #276-1551 .2.99 M Radio /hack America's technology > DO o X to CIRCLE 78 ON FREE INFORMATION CARD How they captured the Olympics. In mid-September 1990. the city of Atlanta, GA celebrated the Interna- tional Olympic Committee's (IOC) announcement that it had been chosen as the site for the 1996 Sum- mer Olympics. Perhaps one of the factors influencing that decision was the high-tech, multi-media presenta- tion of Atlanta's proposal. Developed by researchers at the Georgia In- stitute of Technology with the as- sistance of Georgia State University and several private companies, the innovative system used three vid- eodisc players, three computers, computer-composed music, digitized narration, and a unique interaction system that includes a computer-ani- mated, touch-sensitive model of the proposed Olympic Village. The pre- sentation was controlled by a Com- modore Amiga computer; an Apple Macintosh Ilex and a smaller comput- er-interface device were also used. Computer graphics, which pro- vided both detailed interior scenes and a bird's-eye view of the entire Olympic Village from an altitude of about 500 feet, were merged with real images shot on film; a computer- generated "Golden Athlete" carried the Olympic torch to open the pro- gram. Faced with a tight budget and limited production time, the re- searchers managed to get high-quali- ty images without using multiple cameras by using an anomorphic lens and telecine techniques. Three side- by-side video-projection screens pro- vide a 120-degree wrap-around view. The musical accompaniment was composed and generated on the Amiga computer, which was used to coordinate all the various activities. The presentation package used a touch -sensitive, three-dimensional map of the proposed Olympic village. Animation included clouds, moving vehicles, and a fireworks display, along with the icons used to choose portions of the presentation for view- ing. Because of the raised buildings molded into the maps, conventional FIG. 1— GEORGIA TECH'S MULTI-MEDIA PRESENTATION to the International Olympic Committee included a three-screen computer-generated view of the proposed Olympic Village. touch-sensitive conductive areas or infrared beams couldn't be used. In- stead, load cells located on the four corners of the model sensed pres- sure exerted by users pressing on the icons, and a small computer de- termined what information the user would like to see. A sample of the presentation is shown in Fig. 1. Georgia Tech hopes to use the Olympic project as a stepping stone to the formation of a new, industrially sponsored, multimedia technology research center. Research projects will include telecommunications technology and policy, computer graphics and scientific visualization, translations for the hearing impaired, and a workstation teleconference prototype. Digital simulcast HDTV system. The Advanced Television Research Consortium CATRC) — which includes NBC, the David Sarnoff Research Center, Philips Consumer Elec- tronics Company, and Thomson Con- sumer Electronics, inc. — is focusing on a digital simulcast system that it believes offers a practical digital solu- tion for HDTV. The proposed Ad- vanced Digital Television system, to be jointly developed by the David Sar- noff Research Center and Philips, would preserve existing NTSC chan- nel allocations and ensure the avail- ability of high-quality television images in the United States through the established terrestrial transmis- sion system. According to the ATRC, the digital approach will also increase America's global competitiveness by establishing a digital communications infrastructure that could include other media delivery systems such as ca- ble TV and videocassette recorders. The consortium believes that the most fundamental requirement for a practical digital simulcast HDTV sys- tem is "an NTSC-friendfy digital mod- ulation system." A new modulation technique developed by the ATRC al- lows the digital information to be transmitted at low levels of power so that it doesn't interfere with existing NTSC stations. The digital transmis- sion is also relatively resistant to in- terference from the analog NTSC transmission. Another key development in the digital simulcast system is the intro- duction of a highly efficient digital data-compression approach for en- coding HDTV, The technique allows the high-definition pictures to be squeezed into the existing broadcast- ing frequencies, and provides for good picture performance even in the presence of transmission errors. The consortium hopes that the pro- posed simulcast HDTV system will be the present-day equivalent of the NTSC's "early superhighway for technology" — "a base system that will provide for technological growth and expansion for many decades." The original NTSC system, which offered only black-and-white video with mono audio, was extremely ver- satile. Color was later added to the system, as was multichannel televi- sion sound (MTS) stereo audio, a second audio program (SAP) channel for bilingual programming, and closed captioning for the hearing impaired. It is hoped -that an HDTV system will turn out to be just as flexible. R-E Take any PROFESSIONAL BOOKS only when you join the ELECTRONICS ENGINEERS & DESIGNERS BOOK CLUB : 10015 $42.95 Counts as 2 INDUSTRIAL i:i.i:aki>\k s IHJIINKjAJvS 3321 324.95 9313 339.95 ■ 3203 $44,50 Counts as 2 KNOWLEDGE ENGINEERING 60386 IluM COMPATIBLE AND SAVE k 3TOD1I ri Algorithms onuraphs .5c .32; PRINTED CIRCUITS DESIGN Featuring Computet Aided Technolocjle* Essafwt Qinito Rcfrmtce Q'tidr 3297 S3 9- 95 CUECTEOJJTCliliHICAl DESIGN ilKIIEBCCK ♦ 3102 S49.5D Counts as 2 PRACTICAL TBMSFORMEfl OfSfCN «AiV0BOOK 3212 S34.95 3131 S26.95 3429 $29.95 10016 S39.95 Counts as 2 3279 536.95 -^■■M C4 HANDBOOK H ^^-Jf 9319 359.50 Counts as 3 THE EUCVCLOPEW* OF « ELECTRONIC , CIRCUITS 3098 344.50 Counts as 2 5-244P 318.95 3147 336.95 WE PRBSttHMMBLE LOGIC DEVICE HMIDBOOK 3140 S49.95 Counts as 2 9305 359.50 .,- KB * A0 « 9246 S33.95 Counts as 3 rfiarar *™.so counts as 2 All books are hardcover unless number Is fallowed by a "P" for paperback. 01991 EEDBC. Blue Ridge Summit, PA 1729*0680 2672 349.50 30S9 $34.95 Counts as 2 3151 339.95 1938 360.00 Counts as 2 How the Club Works YOUR BENEFITS: You get 3 books for $4.95 plus shipping and handling when you join. You keep on saving with discounts up to 50% off as a member. YOUR PROFESSIONAL BOOKSTORE BY MAIL: Every 3-4 weeks, you will receive the EE&D Book Club New;; describing the Main Selection and Alternates, as well as 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 selection at all, simply indicate your choice on the reply form provided. You will have at least 10 days to decide. As 3 mem- ber, you agree to purchase at least 3 books within the ne\l 2 years and may resign at any time thereafter. BONUS BOOKS: Starting immediately, you will be eligible for our Bonus Book Plan, with savings of up to 805 off publishers' prices. 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 select- ed by our Editorial Board, (Publisher' Pricss Shown) Your source for quality, affordable and timely authoritative engineering books. ELECTRONICS ENGINEERS & DESIGNERS BOOK CLUB SM Blue Ridge Summit, PA 17294-0860 □ YES! Please accept my membership in the Electronics Engineers & Designers Book Club and send the 3 volumes I have listed below, billing me $4.95. If not satisfied, I may return the books within 10 days without obligation and have my membership cancelled. I agree to purchase at least 3 books at regular Club prices during the next 2 years, and may resign any time thereafter. A shipping/handling charge and sales tax will be added to all orders. City . Zip . Signature | Vilid lor new members only, foreign applkani* wi]l receive apecitt] ordering irrtlnicrrons. Canada ntmt remit in U.S. Kind*. This. I tmter subjecl O to CO VIDEO NEWS DAVID LACHENHRUCH • RCA adopts VCR Plus . VCR Plus + . the instant VCR-pro- gramming system keyed to special code numbers printed in program list- ings of newspapers and some edi- tions of TV Guide (Radio-Elec- tronics, October 1990), will be built into some models of RCA VCR's. according to manufacturer Thomson Consumer Electronics. The program code listings premiered last De- cember in some 30 newspapers and reports at that time indicated a sellout of the $59,95 remote-control gadget, which could program most VCR's and cable boxes. The version to be built into RCA VCR's will use on- screen prompts. It won't program ca- ble boxes, however. • Is it really stereo? Some TV sets that are advertised as receiving "broadcast TV stereo" are not deliv- ering the goods, according to dbx Technology Licensing, which admin- isters patent rights on one compo- nent of the multichannel TV sound CMTS) system. Those sets have ster- eo amplifiers and two sets of speak- ers — the necessary ingredients for stereo sound — but fail to properly de- code the received TV audio signal, the licensing company says. When the MTS standard was adopted by an all-industry committee in 1983, a major component was a companding, or noise-reduction, sys- tem. The dbx system was chosen, and stations broadcasting with ster- eo audio were required to encode the signal using the dbx process. To prop- erly receive the audio signal in stereo, according to the committee, re- ceivers were to include a dbx decod- ing system. Some TV sets being marketed today don't use dbx decod- ing, employing instead other types of expanding circuitry or simply a filter. The purpose, presumably, is to save money, including the licensing fee. However, the chief engineering of- ficial of one TV-set manufacturer that does use dbx throughout its line maintains that use of dbx circuitry adds a maximum of only $2 to the cost of a set, or perhaps 10% to 15% FAROUDJA's CFD-3 decoder is part of the SuperNTSC system. of the cost of adding stereo (dual amplifiers and extra speakers). The dbx licensing organization and some set manufacturers maintain that receivers that don't use dbx have as little as 3- to 4-dB of stereo sepa- ration under some conditions — not enough to provide any noticeable stereo effect — and can add noise, "pumping" effects, and wandering or shifting sound in many cases, dbx Technology Licensing calls that "pseudo stereo" and says it plans to initiate an advertising and public-rela- tions campaign to urge buyers to in- sist on TV receivers with dbx decoders. Manufacturers of TV brands that don't use dbx in some of their sets have steadfastly refused to comment on the situation. • SuperNTSC. As we went to press, SuperNTSC was scheduled for a nationwide test as an alternative to high-definition TV SuperNTSC, developed by Yves Faroudja. who de- signs picture-clarifying broadcast systems, uses many different tech- nologies to produce the best possi- ble picture from the existing National TV System Committee CNTSC) color standard. Backed by ABC, Continen- tal Cablevision. General Instrument, Scientific-Atlanta, Viacom, West- inghouse, and other powerhouses in broadcasting and cable, the system uses a combination of image-pro- cessing techniques to remove ar- tifacts from the NTSC picture. In addition, signals are originated in non-interlaced scanning at 1,050 lines per second and converted to a standard 525-line NTSC signal just before transmission. A standard re- ceiver will display a conventional im- age, but a SuperNTSC set will capitalize on all of the picture im- provements and convert the picture back into 1,050 non-interlaced lines. According to inventor Faroudja, a Su- perNTSC decoder should add about $300 to the cost of a TV set. • Big-screen sets grow. Although 1990 was the first year in the last eight in which TV set sales didn't set a record, large-screen set sales rose. An analysis of sales fig- ures for last year's first nine months shows that table-model sets in the 27-to-29-inch screen sizes were up 26.4% from the same period in 1989, while the 30-inch-and-up category rose about 96%. All sizes below 27- inch, except 20-inch, declined (and 20-inch was up just 1%). Projection- TV sales set a new record in 1990, and for the first nine months were up nearly 30%. Confirming the trend to higher-val- ue TV sets in 1990 were figures on sales for January through October. In that period, multichannel TV sound CMTS) was built into 31.7% of all sets sold, up from 27.6% in the compara- ble period of 1989. • SkyPix. The 80-channel direct satellite-broadcasting system, which bills itself as "the first in-home video store," plans to start broadcasting next summer and is already lining up retailers for its complete receiver package — dish, decoder, and every- thing needed to convert a standard TV set to receive its DBS signal — which will carry a list price of $699. SkyPix s compressed signals will in- clude 40 to 50 channels of pay-per- view movies, according to its de- velopers, and will transmit a picture with 480 lines of horizontal resolu- tion, considerably better than Super VHS or laserdisc. R-E A Shocking Offer! Now for the first time in CiE's 56 year history you do not have to be enrolled at CIE to receive our introduc tory Electronic and Electricity Lesson Modules, Available for a limited lime to non-students for the shockingly low price of only $99.50. With CIE's patented AUTO-PROGRAMMED method of learning you'll quickly learn and then master the basics of electronics and electricity and then move on to.,. DC/AC circuit theories, fundamentals of bi-polar junction transistors (BJT), field effect transistors (FET), wiring, diagram and sche- matic readings, component identification, soldering techniques... and much, much, more. Your commitment to CIE ends with your payment, but CIE's commitment to your success just begins when you receive your (X"^ ■ - 39 lessons, exams, binders and equipment. This special introductory price includes all the benefits and assistance CIE normally extends to its students and graduates. You'll be entitled to unlimited access to CIE's faculty and staff to assist you in your studies via a toll free 800 number six days a week, 24-hour turnaround on grading your submitted exams, CIE Bookstore privileges, a patented learning method, reference library, a student, faculty and alumni electronic bulletin board and a free issue of CIE's school newspaper The Electron, All this knowledge and support will put you on the road to understanding digital electronics, microprocessing principles, computer systems, telecom- munications, and much, much, more. -■-,, %>- • Free Issue of The Electron • Build your personal burglar alarm • instructors available 6 days a week • 20 lesson books containing 39 theory and hands-on training lessons and exams. $ All This and Much More For ONLY! 149 50 ■ Bookstore Privileges ■ Patented Learning Method • Electronic Bulletin Board ' 24-Hour Grading '. Yes, send me CIE's 39 Introductory Electronic and Electricity Lessons and Equipment. Name: Address: City: . State: Age: _ BK03 .Apt. #: _Zip: _Phone ( .) BOOKSTORE 1 776 East 1 7 lit Stmt Cli-i eland. Ohio 441 14 (2I6)781- ( J4(W Total Merchandise: Ohio Residents add 7% Sales Tax: California Residents add 6-1/2% Sales Tax: Total this order: $149.50 Method of Payment: Amount Enclosed , . . $ □ Personal Check or Money Order 3 Master Card □ Visa □□□□□□□□□□□□□□DO Card Expiration Date: - — Signature . CHARGE BY PHONE! > 33 O 9 AM to 4:30 PM Eastern Time; from Ohio 1-800-523-9109 from all other states 1-800-321-2155 What's you Analyzing TV and complex video signals? » 211m LIS U QM2 It'i l.tl u im.i — — -^ _r\^ ncauine i 4 tern smje oh 4 |MH£H«L EHUELOrE nut £H|0FF OHfOFF Testing telecommunications signals? Mil* 0.01 36U IRiij i-a.Bfi? ~ar»a.t75«s sRcr ! a shut — C-*» 9- _r r O^J StUtPLE Uncovering elusive glitches? l»5i.i 6*0. O.U r Finding aberrations buried within a signal? You can't depend on banner specs alone to solve problems like these. Whether you're trying to measure waveform parameters or analyze long data streams, identify infrequent events or track down glitches as narrow as 2 ns — there's all the difference between the depth of Tek troubleshooting and the trade-offs in other DSOs that compromise your results. Spec for spec, feature for feature, no other company offers the credentials Tek does to SflUE ■ \ ( 'y\AfVv pxi sa.s Capturing single-shot events? ie«pi i.rt «•■• uit- «b u 2et|>i ACQUIRE 1 32 MPE7 SftUE ON a MOtrtKL tWttOPE mil PHI Off £g|OfF Automatic PASS/FAIL testing? effectively match DSO performance to your application needs. Whatever your criteria, you'll find a perfect solution in our line of problem-solving portable DSOs, from 10 to 500MS/S. Select the features to support your application. Tek DSOs offer a diverse set of capabilities including peak detect to uncover elusive glitches. Fast update rate for live signal display. Combined analog/digital operation for real-time verification of your Copyrighl © 1990, Tdunmii. IlK, All ri^hls reserved. BOB- 125 L problem? IUB.WV TRJ'3 1>Q.06C> at-a.005«s ■ ■ 6Ut.0.Blu TR|ij )■ SREF a B SftOE SREF i A & M ■~s ^s- "•v-' / BCCPta* B.5«» Characterizing signal noise * QS SflUE - ■ *» ~\ •/ —^~~ J \^_i— ^ I / — h* — — J- -x .~ , .;.! Capturing and analyzing long data streams? Measuring timing relationship between signals? IBOxi J. 52 U UCtlH fMCIU 2U ".A JO,,, J . 5< U UEF!« HCH1 SltiU ft Mm 535.U UIX «.IH53ttHt B" 1 :,9B U JH " 136. dBn, ■'" " « ■-■ . . mi UIOTM I ])<>• • Cll. OK FUNCTION UOLTS Tlflt UtT SLort 1* 'erforrning complex measurements automatically? cur a up rut" Expanding glitches for close analysis signal. Or Save on Delta to automatically verify that all parts of your signal fail within prescribed limits. Best of all, Tek's line of 100 MS/s digitizing scopes start at just $3995. To find out which Tek scope is right for you, contact your Tek representative, return the card or call Tek direct. We can answer your questions and show you a scope that doesn't just look good on paper. It makes your toughest troubleshooting challenges routine. 1-800426-2200 « Windowing in on signal details? One company measures up. Tfektronix dsmmtt-ed to cxccll£«c£ CIRCLE 92 ON FREE INFORMATION CARD ASK R-E NO COLOR TITLES I recently purchased a pro- gram called "Video Titler Plus" for my old Apple II Plus Computer. It's produced by a company called Datasoft and is designed to let you create graphic titles on the computer and then transfer them to your VCR. The problem I'm having is that none of the titles show up in color on my TV. Is there any way to get my Apple graphics recorded in color without actually pointing a camera at the computer screen? — M. Marks, Pitts- burgh, PA Even though some may think of electronics as an exact science, the best answer I can give you in this case is a definite maybe. It may not be all that satisfying, but what can I tell you? Since you can get the titles up on the screen, there's evidently no prob- lem with the software, which is a good thing since I believe that the company who produced it is out of business. The reason you're having a problem getting color in the recorded image is, as you suspect, that the old Apple II Plus, as well as the newer He and llgs, don't generate interlaced video. If you throw the output of the Ap- ple's composite video port on a scope, you'll see that it's real close to NTSC, but when you're talking about video, a miss is as good as a mile. 1 have an Apple II Plus and, back in the old days, used to run the video through a VCR to get an instant re- play on some computer games. Some VCR's and TV's (usually the older ones), would swallow the Apple video and produce color images. The newer video equipment is much more finicky about details like interlace and. if the waveform isn't a real close match to NTSC, color disappears. It's amazing how important half lines can be. I can offer you three possibilities for solving the problem but I'm not going to guarantee that any of them will work. The first, and most obvious, is to try an older VCR, or at least a different one. Based on the experi- ence ! had, cheaper models with fewer features seem to be a better choice. The second option is to try adjust- ing the operating frequency of the Apple itself. That's fairly simple to do since there's a small trimmer capaci- tor in the main clock circuit located between A1 and B1 on the mother- board. Those are Apple's grid coordi- nates and you'll find them along the edges of the board. If the Apple is slightly off frequency, the burst fre- quency will be off as well and the difference may be enough to keep your VCR from recognizing it. You should use a scope for this but, if you don't have one, a bit of freehand experimentation can't hurt anything. Just be sure to mark the original position of the trimmer in case you run info problems. A second trimmer is on the motherboard at lo- cation G14 and you can play around with that one as well. It changes the phase angle of the burst and will change the hue of the colors on the screen. It shouldn't do anything to help your problem, but then again, you never know. If none of those two work, your only available option is to look around for some hardware that will solve the problem. Quite frankly, I wouldn't hope for much since the computer is rather old. It's true that there are some expansion slot similarities be- tween it and the later He, but that whole market isn't what it used to be. Check with some Apple magazines and, if all else fails, you might try con- tacting Apple itself. Good luck. A LONG PLAYING RECORDER How would I modify an ordi- nary cassette recorder to make it into a super long-play- ing recorder? I understand only one or two electronic components are necessary. — L. Krenek, La Grange, TX I haven't had the occasion to take apart a wide variety of cassette re- v MO TOR ■O FIG. 1— YOU CAN USE THIS CIRCUIT to control the speed of a small DC motor. corders but the ones I have seen are easily modified to increase the re- cording time. Before we get any fur- ther along with this, you should NEVER try to modify store- bought equipment without either a lot of pa- perwork, a lot of experience, or a lot of nerve. Consumer stuff has gotten so sophisticated that opening the case often requires a manual. But seriously folks, most good cassette recorders can be modified without adding any components at all. The motor has a tachometer on it that the cassette's circuitry uses to monitor the speed of the motor and make sure that the speed remains constant. Some motors have a small AC generator running off the motor shaft inside the motor housing, and others have a small pickup head mounted outside the motor that gets pulses from a metal wheel attached to the motor shaft. In any event, the frequency gener- ated by the tachometer is fed to a small circuit that converts it to a volt- age and measures the resulting value continued on page 92 12 ELENCO & HITACHI PRODUCTS AT DISCOUNT PRICES -i\ RSOs (Real-Time & Storage Oscilloscopes) From HITACHI a. v$^ The RSO - Its the new solution vfj^ View, Acquire, Test, Transfer and Document Your Waveform Data '■ 4-Channet. lOGMS/s Model Introductory Price tOOM&s (25MS/S tm * channels simultaneously), lOOMHz, *kwx left., 2In»x 2ch., tkwx4crt. VC-S1*5 $4,695.00 Compact, Full Feature Models VC-6045 $3,049.00 VC-6025 $ 2,295.00 40MS/S, I00MHI, 4kwx1cti., 2kwx!ch. 20MS/S, 50MHz, 2kw x 2ch. Low Cost/High Volue Models 20MS/S, 50MHz, 2kv* x 2cfi. VC-S024 $ 2,049.00 20MS/S, 20MHz, 2kw x 2cft. VC-6023 $1,749,00 RSOs from H hachi feature such functions as roll mode, averaging, save memory, smoothing, interpolation, pretrigge ring, cursor measurements, plotter interface, and RS-232C interface. With the comfort of analog and the power of digital. V-212 $435 V-422 40MHI Dual Trace Hitachi Portable Scopes DC to 50MHz, 2-Chomnel, DC offset , function, Alternate magnifier (unction Dual Channel vs25 CRT Readout, Cursor Me as. $1 ,025 V-523 Delayed Sweep $995 $795 V-522 Basic Model 5895 Compact Series Scopes Delayed Sweep Lightweight (13lbs) 2mV Sens 3 Yr Warranty Model V-1 065 Shown This series provides many new functions such as CRT Readout, Cursor measurements (V-1 085/1 065/665), Frequency Ctr (V-1085), Sweeptime Autoranging and Trigger Lock using a 6-inch CRT. Vou don't teel the compactness in terms o) performance and operation. V-660 60MHz Dual Trace $1,195 V-665 60M Hz Dual Trace w/Cursor $1 ,345 V-1 060 1 00MHz Dual Trace $1 ,425 V-1065 100MHz Dual Trace w/Cursor $1,695 V-1085 100MHz Quad Trace w/Cursor $2,045 V-1100A 100MHz Quad Trace w/Cursor $2,295 V-1 150 150MHz Quad Trace w/Cursor $2,775 20MHz Elenco Os cilloscope $375 MO-1251 • Dual Trace • Component Tester • 6' CRT • X-Y Operation • TV Sync • 2 p-i Probes FREE DMM with purchase of ANY SCOPE SCOPE PROBES P-l 65MHz, lx. lOx $19.95 P-2 lOOMHz, lx.lOx 523.95 Elenco 35MHz Dual Trace * AA£ GoodtoSOMH? **»yo MO- 1252 • High luminance 6' CRT • 1mV Sensitivity • 6KV Acceleration Voltage ■ 10ns Rise Time • X-V Operation * Z Axis • Delayed Triggering Sweep • Includes 2 P-1 Probes All scopes include probes, schematics, operators manual, and 3 year (2 yrs for Elenco scopes) world wide warranty on parts & labor. Many accessories available for all Hitachi scapes. Call or write for complete specifications on these and many other tine oscilloscopes. WE NOW CARRY COMPLETE LINE OF FLUKE MULTIMETERS Models 21F 83 23F 85 25F 87 27F 8050A 73 6060A 75 8062A 77F + More CALL FOR SPECIAL PRICING P True RMS 4 1/2 Digit Multimeter M-7000 $135 .05% DC Accuracy .1% Resistance with Freq, Counter and deluxe case Function Generator Blox #9600 $28.95 tu§ Provides sine, Mingle, square wave from tHzto 1MHz AW or FM capability r innn • 10 Function Multimeter CM -365 $65 T AC + DC Voltage & Amps ,j, Resistance to 20O0MQ Diode, Logic, S Trans lest ■ Capacitance to 200 uF Digital Capacitance Meter CM- 1550 $58.95 & Ranges 1pf-20,QWuld 5% basic accy Zero control with case Triple Power Supply XP-620 Assembled $65 Kit $45 2to1SVal1A. -2 to -15V at (A (or 4 to 30 V at 1 A) and 5V at 3A Contains all the desired features for doing experiments. Features short circuit protection, all supplies. L'«V Digital LCR Meter j^_ LC-1801 $125 ^p*^k Measures: IKJI Coils 1uH-200H \^ Caps .1pt-200uf He Res .01-20M Wide Band Signal Generators SG-9000 $129 RF Freq 100K -450MHz AM Modulation of IKHz Variable RF output SG-9S00w Digital Display and 1 50MHz built-in Counter 1249 $69.95 |t^AC Current Meter | J ST-1010 1 1000 Amps | Daia & Peak hold 8 Functions Deluxe Case *I# Decode Blox ~~T*%10or #9620 $18.95 19610 Resistor Bloi 47ohmto1M£100Kpat *%20 Capacitor Bloi 47pfto10Mf : Quad Power Supply XP-580 $59.95 Fully regulated an3 short circuit protected XP-57S without meters 139.95 LEARN TO BUILD AND PROGRAM COMPUTERS WITH THIS KIT! INCLUDES: All Parti, Assembly and Lvtton Manual Model MM-8000 $129.00 Digital Triple Power Supply XP-765 $249 0-20V it 1A 0-2OV it U 5Vit5A Fuly regulated. Short circuit protected with 2 limit control, 3 separate supplies XP-660 with Analog Meters $175 GF-8016 Function Generator with Freq. Counter $249 Sine, Square, Triangle Pulse, Ramp. .2 to 2MHz Freq Counter .t - 1QMK; .L~.,.-|...» GF-6015 without Freq. Meter 5179 Starting from scraich you build a complete system. Our Micro-Master trainer teaches- you to write into RAM*, ROMs and ru n a 80&5 m icropfocos- sot, which uses similar machine language as IBM PC You will write the initial instructions to tell the 9065 proce&sorto opi started and store these instructions in permanent memory in a 29 1 6 E PROM. Teaches you all about inpul and output ports, computer timers. Build your own keyboard and learn how to scan keyboard and display. No previous computer knowledge required. Simple easy to understand instruction teaches you to write in machine language. ROBOTICS KIT FOR ABOVE (MM-&010) $71,95 WE WILL NOT BE UNDERSOLD! C & G CAT FS IMP UPS Shipping. 48 States S^g—u-^ n4$ Rosewood Deerfie i d , j L 6m5 ($10 Max) IL Res.. 7% Tax Pr*g§g (gnrj) 292-7711 (708) 541-0710 15 Day Money Back Guarantee 2 Year Warranty prices si^ta m ctan gs WRITE FOR FREE CATALOG CIRCLE 109 ON FREE INFORMATION CARD 13 COMMUNICATIONS AOR Scanners. Great Performance. Great Service. Great Value. Free Freight 25-Day Money-Back Guarantee Toil-Free Service and Support No Credit Card Surcharge One Year Warranty AR1000 $499 to o LLJ I UJ i O § DC 14 1000 Channels. 8-600MHz, 805-1300MHz Standard Features: • Extremely compact size. • Continuous coverage (except UHF TV 600-805) ■ Antenna attenuator switch, lOdb. • Manual tuning knob. • Earphone jack, 3.5mm. - AM, FM and wide band FM tuning modes. ■ Backlighted LCD display. ■ 10 Scan Banks, 10 Search Banks. ■ Selectable Priority Channel. ■ Delay, Hold Features. ■ Selectable Search Increments, 5-955KHz. ■ Permanent memory backup. ■ 4 A A Ni Cad batteries included. • AC adaptor /charger. ■ Carry Case. ■ Cigarette Lighter Charger. ■ Belt Clip. ■ Earphone. Options: External Speaker. Mobile Mount. MS190 $19.50 Extended Warranty. 2/3 yrs $45/ $55 Specifications: Coverage: Sensitivity: Speed: IF: Increments: Audio: Power: Antenna; Display: Dimensions: 8-600, 805,1300MHz .35uV NFM, l.OuV WFM, LOAM 20 ch/sec. scan. 40 ch/sec. search 561.225, 58.075, 455KHz or 10.7MHz 5 to 955KHz selectable/ 5 or 12.5 steps, .4 Watts Input 9 -13.8 V. DC BNC LCD 6 7/8Hxl3/4Dx21/2W. 12ozwt. AR950 $239 100 Channels. Low, Air, High, UHF & 800MHz. Standard Features: ■ Extremely compact size. ■ Unrestricted 800MHz coverage. ■ 100 channels permanent memory. • Earphone Jack & Attenuator. ■ Delay, Hold features. ■ Channel 1 Priority. ■ 5 Scan Banks, 5 Search Banks. ■ Telescopic and Flexible Antennas w/ BNC connector. ■ AC & DC Power cords w/ mtng hardware. ■ One Year Limited Warranty. Options: Base type antenna 25 to 1000MHz w 50'coax. Mag Mnt Mobile Antenna. 15' coax. Cigarette Lighter power adaptor. External Speaker with mobile mount. Extended Warranty. 2/3 yrs Specifications: Coverage: Sensitivity: AS300 $59.95 MAI 00 $25.00 CP100 $4.00 MSI 00 $19.50 $40/$55 27-54, 108-174, 406-512, 830-950MHz .4uV Lo,Hi. .8uV Air. .5uV UHF. l.OuV 800 Scan Speed: 15 ch/sec. IF: 21.4MHz, 455KHz Increments: 10,12.5,25,30 Audio: 1W Power: 12.8VDC, 200MA Antenna: BNC Display: LCD w/backlight Dimensions: 2 1 /4H x 5 5/8W x 6 1 /2D. 14oz wt. We offer 100's of communications products. CIRCLE 180 ON FREE INFORMATION CARD COMMUNICATIONS AR2500 $499 2016 Channels. 1 MHz to 1500 MHz Standard Features • Continuous coverage •AM, FM, wide band FM, & BFO for SSB, CW. •64 Scan Banks. • 16 Search Banks. • RS232 port built in. •Includes AC /DC pwr crd. Antenna, Mntng Brckt. • One Year Limited Warranty. Options: Earphone. EP200 $2.00 External Speaker. Mobile Mount. MSI 90 $19.50 Extended Warranty. 2/3 yrs. $65/75 Mobile Mounting Bracket. MM1 $14.90 RS232 Control Package SCS2 $295.00 (software & cable) offers spectrum display and database. Specifications: Coverage: 1 MHz - 1500MHz Sensitivity: .35uV NFM, LOuV WFM, 1.0AM/SSB/CW Speed: 38 ch/sec. scan. 38 ch/sec. search HF: * 750.00, 45.0275, 5.5MHz 455KHz Increments: 5,12,5,25 KHz Audio: 1 .2 Watts at 4 ohms Power: Input 13.8 V. DC 300mA Antenna: BNC Display: LCD, backlighted. Dimensions: 2 1 /4H x 5 5/8W x 6 1 /2D Wt, lib. AR3000 $995 400 Channels. lOOKHz to 2036MHz. Standard Features: • Extremely compact size, • Continuous coverage • Attenuation Programmable by Channel. • Manual tuning knob. •Tuning increments down to 50Hz. • AM, FM, wide band FM, LSB, USB, CW modes. • Backlighted LCD display. •4 Scan and Search Banks, Lockout in Search. • 4 Priority Channels. • RS232 control through DB25 connector. • Delay, Hold Features. • 15 band pass filters, GaAsFET RF amp. •Sleep and Alarm Features. • AC adaptor/charger. DC power cord. •Telescopic Antenna. Options: Earphone. EP200 $2.00 External Speaker. Mobile Mount. MSI 90 $19.50 Extended Warranty. 2/3 yrs. $65/75 Mobile Mounting Bracket. MM! $14.90 RS232 Control Package 5CS3 $295.00 (software & cable) offers spectrum display and database. Specifications: Coverage: lOOKHz - 2036MHz Sensitivity: ,35uV NFM, LOuV WFM, 1.0AM/SSB/CW Speed: 20 ch/sec. scan. 20ch/sec. search IF: 736.23, (352.23) (198.63) 45.0275, 455KHz Increments: 50Hz and greater Selectivity: 2.4Khz/-6db (SSB) 12KHz/-6db (NFM/AM) Audio: 1 .2 Watts at 4 ohms Power: Input 13.8 V. DC 500mA Antenna: BNC Display: LCD Dimensions: 3 1 /7H x 5 2/5 W x 7 7/8D Wt. 21b lOoz. To Order Call 1 • 800 • 445 • 7717 In All 50 States and Canada. 24 Hours a Day. Fax Orders: 1-800-448-1084, 24 Hours a Day. ACE Communications Monitor Division 10707 E, 106th Street, Fishers, IN 46038 Int'I Voice* 317-842-7115. Int'l Fax* 317-849-8794. Service and Support Lines: Mon-Fri 9a.m. to 9p.m., Saturday 10-4. EST MasterCard, Visa, American Express, Checks, Approved P.O.'s. & C.O.D. (add 5.00) Prices and specifications subject to change. > 3D O I — l O I 17 Learn to troubleshoot and service today's computer systems as you build a fully AT-compatible micro Train the NRI way — and learn to service all computers as you build your own fully AT- compatible micro, now with 1 meg RAM, 20 meg hard drive, and exciting new diagnostic hardware and software! Jobs for computer service technicians will almost double in the next 10 years according to Department of Labor statistics, making computer service one of the top 10 growth fields in the nation. Now you can cash in on this exciting opportunity — either as a full-time industry technician or in a computer service business of your own — once you've mastered electronics and computers the NRI way. NRI's practical combination of "reason-why" theory and hands-on building skills starts you with the fundamentals of electronics, then guides you through more sophisticated circuitry all the way up to the latest advances in computer technology. Train with and keep a powerful AT- compatible computer system plus popular Microsoft* Works software! Only NRI gives you hands-on training with the finest example of state-of-the-art technology: the powerful West Coast 1010ES computer. As you assemble this fully IBM PC/AT-compatible computer from the keyboard up, you actually see for yourself how each section of your computer works. You assemble and test your computer's "intelligent" o keyboard, install the power supply and 5-1/4" floppy disk z drive, then interface the high-resolution monitor. h- Your hands-on training continues as you install a uj powerful 20 megabyte hard disk drive — today's most- iii wanted computer peripheral — now included in your course Q to dramatically increase the data storage capacity of your < computer while giving you lightning-quick data access, or 18 Plus you now work with today's most popular integrated software package, Microsoft Works, learning to use its word processing, spreadsheet, database, and communications utilities for your own personal and professional applications. But that's not all. Only NRI gives you hands-on training with the remarkable RJLCEJt. plug- in diagnostic card and QulckTech diagnostic software from Ultra-X— professional, state-of-the-art diagnostic tools that make computer troubleshooting fast and accu- rate. Your NRI computer training includes all this: • NRI's unique Discovery Lab® for circuit design ana testing • Hand-held digital multimeter with "talk-you-through" instructions on audio cassette • Digital logic probe that lets you visually examine computer circuits * The new AT- compatible West Coast 1010ES computer with high-speed 80286 CPU, 101 -key "intelligent" keyboard, 1.2 meg high-density floppy drive, 1 meg RAM (expandable to 4 meg), S4KROM • 20 megabyte hard disk drive • MS-DOS, GW-BASIC, and Microsoft Works software • RjLC.EJI. plug-in diagnostic card and QuickTech diagnostic software for fast, accurate troubleshooting • Refer- ence manuals with guidelines and schematics peripheral adapters as parallel printer ports, serial communications ports, video display memory, floppy drives, and hard disk drives. Only NRI gives you such confidence-building, real- world experience. Only NRI gives you both the knowl- edge and the professional tools to succeed as today's in- demand computer service technician. No experience needed, NRI builds it in NRI training gives you practical, hands-on experience that makes you uniquely prepared to take advantage of today's opportunities in computer service. You learn at your own convenience in your own home. No classroom pressures, no night school, no need to quit your present job until you're ready to make your move. NRI starts you with the basics, building on that foundation step by step until you have the knowledge and skills you need for success. And all throughout your training you've got the full support of your personal NRI instructor and the entire NRI technical staff, always ready to answer your ques- tions and help you achieve your training goals. FREE catalog tells more Send today for NRI's big, free catalog that describes every aspect of NRI's innovative computer training, as well as hands-on training in other growing high-tech career fields. If the coupon is missing, write to: NRI School of Electronics, McGraw-Hill Continuing Education Center, 4401 Connecticut Avenue, NW, Washington, DC 20008. NEW! Training now includes Ultra-X diagnostic hardware and software for quick, accurate troubleshooting! IBM is a registered trademark of International Business Machines Corp. R.A.C.E.R. and QuickTech are registered trademarks of Ultra-X. Inc. Now you train with and keep the latest in diagnostic hardware and software: the extraordinary R.A.C.E.R. plug-in diagnostic card and QuickTech diagnostic software, both from Ultra-X. Using these state-of-the-art tools, you learn to quickly identify and service virtually any computer problem on XT, AT 80286/80386, and compatible machines. You discover how to use the R.A.C.E.R. diagnostic card to identify individual defec- tive RAM chips, locate interfacing problems, and pinpoint defective support chips. Plus you learn to use your QuickTech diagnostic software to test the system RAM and such SEND TODAY FOR FREE CATALOG McGraw-Hill Continuing Education Center 4401 Connecticut Avenue, NW SchOOIS Washington, DC 20008 U| [/CHECK ONE FREE CATALOG ONLY *■&!* [ ] Microcomputer Servicing □ Automotive Servicing □ PC Systems Analysis G Industrial Electronics & Robotics □ PC Software Engineering Using C □ Telecommunications D Small Engine Repair □ Word Processing Home Business □ Electronic Music Technology □ Fiction/Nonfiction Writing □ Air Conditioning, Heating, &. Refrigeration □ Computer Programming C Locksmi thing □ Paraglegal □ Electrician □ Building Construction □ Desktop Publishing & Design □ Security Electronics II TWVideo/Audio Servicing □ Bookkeeping & Accounting □ Basic Electronics For career courses approved under GI Bill, check for details. Name (please print) Age Address I i City/State/Zip Accredited Member, National Home Study Council 3031 Fluke Model 45 Dual Display Multimeter ■~T) O Z O cr !- o CSRCLE 10 ON FREE INFORMATION CARD If you're looking for ways to make your measurement tasks easier, then you'll be interested in the model 45 dual-display multimeter from Fluke (John Fluke Mfg. Co., Inc., P.O. Box 9090, Everett, WA 98206.) The Fluke 45 makes it possi- ble to measure two signal parameters from a single test connection. For ex- ample, you can measure the DC out- put of a power supply at the same time you measure the AC ripple on the output. Or you can measure the voltage of an AC signal at the same time you measure its frequency to, for example, determine an amplifier's frequency response. The Fluke 45 is a 5-digit 100.000- count meterthat is housed in a plastic case that measures about 3 3 Ax 8V2 x 1 1V4 inches and weighs about 5 pounds. (An optional battery adds about two pounds.) Basic accuracy specifications are impressive: DC voltage, 0.02% DC current 0.05%. If you're more interested in speed than in accuracy, fast- and medium- speed measurements can be se- lected from the front panel. While the measurement speed can increase dramatically (20 readings per second in the fast mode as compared to 2Vi per second in the slow mode) the accuracy and resolution of the display decreases (5 digits. 99.999 counts in the slow mode as compared to 3V? digits, 3000 counts in the fast mode). What sets the Fluke 45 apart from the meter you have on your benchtop is its dual display. All measurement functions, including AC and DC volt- age and current readings, resistance, and frequency, can be displayed on either the primary or the smaller sec- ondary readout. Function modifiers increase the versatility of the meter, and can speed up some important measure- ments (although they can be used only with the primary display). For ex- ample, when the rel or relative-read- ings modifier is used, the display shows the difference between the relative base and the input signal. If the relative base is 1000 ohms and the current reading is 1200 ohms, the display will show 200 ohms. The dB modifier takes a voltage measurement, converts it to dBm (decibels measured with respect to one milliwatt) and displays the result on the primary display. The reference impedance can be set to any of 21 values from 2 ohms to 8000 ohms. When the reference impedance chosen is 2,4,8, or 16 ohms, the meter can be used to make audio power measurements. The hold modifier let's you hold a measurement on the display when you might not want to take your eyes off the probes to read the display. It can be used separately or in com- bination with the mn MX or minimum maximum modifier, which lets the meter store the minimum and max- imum inputs measured after the mod- ifier is selected. A compare or comp modifier gives you an easy way to determine if a measurement falls within an accept- able range of values. Once the ac- ceptable range is input (which can be done in several ways), each measure- ment shows either "HI," "Low" or "PASS" in the secondary display. Using the meter Although the Fluke 45 provides some complex measurement ca- pabilities, it's quite easy to use. For standard measurements, it's opera- tion is intuitive — even when using both the primary and secondary dis- plays at the same time. Some of the more advanced functions take a little experience before their use becomes second nature. The meter's front pan- el features a clean, logical layout. Its readout is a bright, easy-to-read vac- uum-fluorescent display. The dual display can speed up some test and measurement tasks dramatically. For example, by measur- ing DC voltage and current (which requires three leads), you can easily check a power supply's load regula- tion. By measuring AC voltage and current, you can determine a trans- former's saturation. The second dis- play can also be used to take full advantage of some of the meter's functions. For example, when the meter is in it's minimum/maximum mode, the secondary display can show the current measurement. Or in the hold mode, the running actual val- ue can be shown in the secondary display while the previously held val- ue is show in the primary display. The Fluke 45 offers an RS-232 in- terface as standard equipment for sending or printing measurement data. Reading rates can be adjusted from one reading every 75 ms to one reading every 5.6 hours. An optional IEEE-488 interface is also available. Not everyone needs the accuracy and convenience that the Fluke 45 offers. Even some who do might balk at the unit's suggested retail price of $635. This is a case, however, of get- ting what you pay for. R-E 22 ElectnmiEs* DtjDDDt)D°Md) SIMPLY SNAP THE WAT-50 MINIATURE FM TRANSMITTER on top of a 9v battery and hear every sound in an entire house up to 1 mile away! Adjustable from 70-130 MHZ. Use with any FM radio. Complete kit $29.95 + SI. 50 S 4 H. Free shipping on 2 or more! COD add S4. Call or send VISA, MC. MO. DECO INDUSTRIES, Box 607, Bedford Hills, NY 10507. (914) 232-3878, CIRCLE 127 ON FREE INFORMATION CARD sststrv GENERAL TECHNICS COMPUTER KITS offer a complete line of 8088, 286, and 386 models. Designed to the highest degree of quality and reliability available today. They're also fun, easy to build, educational, fully IBM compatible, very powerful, and at wholesale prices Ail kits are pre-tested and include a one year warranty, step by step assembly manual, free software, and a 24 hour tech support/order phone line. For free catalog contact. GENERAL TECHNICS, P.O. BOX 2676, LAKE RONKONKOMA, NY 11779, or call (516) 981-9473, VISA. MasterCharge, American Express, COD CIRCLE 191 ON FREE INFORMATION CARD l^^ff- 1 j . y FREE CATALOG! ELECTRONIC TOOLS & TEST EQUIPMENT, Jensen's new Master Catalog, available free, presents major brand name electronics tools, tool kits, and test in- struments, plus unique, hard-to-find products for assembly and repair and custom field ser- vice kits available only from Jensen. All fully described and illustrated. Enjoy free technical support and rapid, post-paid delivery any- where in the Continental USA. JENSEN TOOLS INC., 7815 S. 46th St., Phoenix, AZ 85044. Phone: 602-968-6231; FAX: 1-800-366-9662. CIRCLE 115 ON FREE INFORMATION CARD rruu .*?* CABLE TV CONVERTERS AND DE- SCRAMBLERS SB-3 S79.00 TRI-BI S95.00 MLD-S79.00 M35B $69,00 DRZ-DIC $149.00. Special combos available. We ship COD. Quantity discounts. Call for pricing on other products. Dealers wanted. FREE CATA- LOG. We stand behind our products where others fail. One year warranty. ACE PROD- UCTS. P.O. Box 582, Saco, ME 04072 1 (800) 234-0726. CIRCLE 75 ON FREE INFORMATION CARD TS-8-MTS VIDEO TEST SIGNAL GENER- ator with Stereo Multi-channel Television Sound (MTS) Option— 8 Test Signals. 8 bif digital accuracy. Second Audio Program (SAP), 4 frequencies of tone, RGB Color Bar output. Horizontal and Vertical triggers, chan- nel 3 or 4 RF output. 3 year warranty. TS-8 Price: S845. MTS Option price: S245. Visa, MC, C.O.D. Dealers wanted. Free brochure. MULTIDYNE ELECTRONICS, INC., 244 Bayville Avenue, Bayville, N.Y. 11709, 1-(800).765-8200, (516) 628-1495 CIRCLE 177 ON FREE INFORMATION CARD NEW XST500 SUPER-MINIATURE FM transmitter uses Surface Mount Technology (SMT)! Own the smallest high performance FM transmitter available. Transmits whispers to any FM receiver up to a mile away. Uses 9V battery. Complete, easy to assemble kit, with SMT components already assembled to cir- cuit board. S39.95 Cash, VISA. MC. COD add S5. XANDI ELECTRONICS, 201 E. South- ern Ave., Suite 114, Tempe, AZ 85282. 1-602-829-8152, (1-800-336-7389 orders only). CIRCLE 18B ON FREE INFORMATION CARD CALL NOW AND RESERVE YOUR SPACE • 6 x rate 5940,00 per each insertion. • Fast reader service cycle. • Short lead time for the placement of ads. • We typeset and layout the ad at no additional charge. Call 516-293-3000 to reserve space. Ask for Arline Fishman. Limited number of pages available. Mai! materials to: mini-ADS, RADIO-ELECTRONICS, 500- B Bi-County Blvd., Farmingdale. NY 11735. FAX: 516-293-3315 THE MODEL WTT-20 IS ONLY THE SIZE OF A DIME, yet transmits both sides of a tele- phone conversation to any FM radio with crystal clarity. Telephone line powered - never needs a battery! Up to W mile range. Adjusta- ble from 70-130 MHZ. Complete kit $29.95 + $1.50 S f H. Free Shipping on 2 or more! COD add $4, Call or send VISA, MC, MO DECO INDUSTRIES, Box 607, Bedford Hills. NY 10507. (914) 232-387B. CIRCLE 127 ON FREE INFORMATION CARD APPLIANCE REPAIR HANDBOOKS— 13 volumes by service experts: easy-to- understand diagrams, illustrations. For major appliances (air conditioners, refrigerators, washers, dryers, microwaves, etc.). elec. housewares, personal-care appliances. Basics of solid state, setting up shop, test instruments. $2.65 to $7.90 each. Free brochure, APPLIANCE SERVICE, P.O. Box 789, Lombard, IL 60146. (312) 932-9550. CIRCLE 84 ON FREE INFORMATION CARD > o 23 Use the Free Information Card for more details on these products, V) y z O DC ID 6 < CC PORTABLE DSO/DMM. The battery-powered, 30- megasamples per second model 300 from Leader In- struments combines a dig- ital-storage scope and a digital multimeter in one portable unit. The model 300 features dual, add, subtract, and X-Y modes; peak-to-peak voltage of channels 1 and 2 and fre- quency readout; and auto- matic setup and auto- ranging for both time base and volts per division for each channel. The instru- ment measures just 9 7 /iex6 1 /2X 1 3 /4 inches and weighs about 2'/i> pounds without batteries. Its large, supertwist LCD readout provides high contrast and a wide viewing angle. On- screen setting conditions that are available include time base, sensitivity for both channels, vertical mode, sweep mode, mem- ory length, trigger slope and source, type of filter, trigger position, bank number, and display mode. ":::- • _• • Cl I 1—7 ' : ~ dLJ ■ *" CH1.«t 3 Q ! I CIRCLE 16 ON FREE INFORMATION CARD The model 300 has a memory length of 1.8K words per channel and can store 20 waveforms. Up to 80 waveforms can be stored with an optional IC card, which makes it possi- ble to store field informa- tion for analysis later in the lab. A data-logger function takes long-term measure- ments of DC and AC volt- age and current, resis- tance, low-power resis- tance, diode test, and continuity check that can be stored in the optional IC card or printed on an op- tional dedicated printer. An 8-bit logic-analyzer func- tion is handy for remote field-service applications. The model 300 portable DSO/DlvIM costs $1995.00.— Leader in- struments Corpora- tion, 380 Oser Avenue, Hauppauge, NY 11 788: Tel: 1-800-645-5104 or 516-231-6900 in NY PC-DIAGNOSTICS CARD. Designed for ser- vice technicians, repair centers, dealers, and man- ufacturers. Landmark's KickStart 2 is an advanced, multifunction PC-diag- nostics card that combines firmware and hardware in a compact plug-in board. With up to one megabite of on-board EPROM, it per- CIRCLE 17 ON FREE INFORMATION CARD forms both low-level (POST) and advanced (ROM-based) diagnostic tests of the motherboard, memory, and major pe- ripheral controllers. The tests are suitable for diag- nosing system failures and burning in systems, KickStart 2 provides built-in I/O. password pro- tection, and remote test- ing. The remote function allows a technician to per- form on-site testing and password protection ac- tivities from a home office using a modem. For testing purposes, a pair of "JumpStart" BIOS ROM's are provided. The firmware is modular, so customiza- tion is possible. Digital LED readouts show the POST codes sent to port 80 and 280. Battery backup keeps configuration and pass- word information intact. Loopback plugs are pro- vided for complete serial- and parallel-port testing. The KickStart 2 has a suggested retail price of $599,00.— Landmark Research Interna- tional Corporation, 703 Grand Central Street, Clearwater, FL 34616; Tel: 813-443-1331 ; Fax: 813-443-6603. SOLDER PASTE KIT. For those who would like to try using homogeneous sol- der paste instead of flux- core solder wire, ESP's Kit-5 contains five pre- packaged barrels of solder- paste alloy, molded dis- pensing tips, and a reusa- ble dispenser for precise solder application. The kit includes 35-gram barrels of 60Sn/40Pb and lead-free 96Sn/4Ag alloys, supplied with both an activated rosin flux and a water- washable flux. Also included is a pre- packaged barrel of the acti- vated rosin-paste flux for desoldering. CIRCLE 18 ON FREE INFORMATION CARD The Kit-S solder-paste kit costs $89.00.— ESP Sol- der Plus, 14 Blackstone Valley Place, Lincoln, Rf 02865-1145; Tel; 1-800-338-4353. PORTABLE SIGNAL ANALYZER. Weighing only seven pounds, Hewlett Packard's note- book-sized HP 3560A is a fast Fourier transform (FFT)-based, dynamic sig- nal analyzer that provides the measurement speed and functions of a benchtop analyzer. This high-performance portable instrument offers time- and frequency-domain analysis for electronics, vibration, rotating machinery, struc- tural test, acoustics, signal 24 monitoring, and other low- frequency applications. An internal battery pack pro- vides six hours of uninter- rupted operation. The HP 3560A is a two- channel, DC to 40-kHz spectrum/network ana- lyzer with measurement functions including com- plete alias protection and CIRCLE 19 ON FREE INFORMATION CARD digital zoom for high-reso- lution measurements, and an anti-alias filter that can be adjusted for fast-edge, time-domain measure- ments. The analyzer pro- vides a 70-dB dynamic range and ±0.5-dB ampli- tude accuracy for spec- trum measurements; ±0.2-dB, ±5-degrees network measurement ac- curacy; variable frequency resolution from 101 to 1601 lines per display: and on- line zoom, which allows the full resolution of the ana- lyzer to be concentrated anywhere in the 40-kHz measurement range. The signal analyzer can send trace plots directly to printers and plotters through the rear-panel EIA-232D CRS-232C) con- nection. It will print to HP LaserJet and QuietJet printers and plotters includ- ing the HP 7550A and HP 7475A. It can transfer data from internal memory di- rectly to a printer with a ca- pacity of 500 state/trace combinations. A PC-based data-transport utility con- verts HP 3560A data to standard-data format for post-measurement analy- sis by other HP products. Data can also be trans- ported to third-party mea- surement and analysts packages using the in- cluded file utility. The HP 3560A signal analyzer costs $7500. — Hewlett-Packard Company, Inquiries, 19310 Pruneridge Avenue, Cupertino, CA 95014; Tel: 1-800-752-0900. EIGHT-OUTLET SURGE SUPPRESSOR. An auto matic-shutdown circuit turns off all power if the sur- ge-suppressor circuit in Perma Power's LS-812fa\\s due to high-voltage or re- petitive surges. That auto- matic disconnection pre- vents any exposure to unprotected power — an important feature given the usual "out-of-sight" place- ment of surge protectors. The surge protector has a CIRCLE 20 ON FREE INFORMATION CARD lifetime warranty that ex- tends beyond the unit itself to provide equipment-re- pair coverage for protected equipment. The surge sup- pressor features two rows of four outlets in a beige metal case with a 12-foot power cord. The LS-812 incorporates in a hybrid circuit metal-ox- ide varistors CMOVs). ava- lanche diodes, capacitors, and inductors. The LS-812 provides 5-ps response time and high EMI and RFI noise filtering at a low U.L. let-through voltage rating of 330 volts. The LS-812 surge sup- pressor has a suggested retail price of $99.95 — Perma Power Elec- tronics, Inc., 5601 West Howard Ave., Chicago, IL 60648; Tel: 312-763-0763; Fax: 312-763-8330. PERFECT CABLE CONNECTION !! Perfect Cable Connection is totally commuted id customer satisfaction Our primary concern is 1o provide you with the highest quality converters and desoamblets at the (owes! cost We employ full lime technicians to insure hassle tree service and IroublBshoot any situation. Call us today and lei us prove lo you why we are the Perfect Cable Connection « 6 months too*, parts & labor • ;'-', months warranty available ■ Full technical supoort ■ On-line computer system ■ 30 days money back guarantee ■ Most ofcSers shipped within 24 hours ■ Visa. M C. AMEX - 5'. ■ Dealers welcome ■ C.O.Q WE WILL MEET OR BEAT ANY ADVERTISED PRICE IN THIS MAGAZINE. PERFECT CABLE CONNECTION 702-358-2763 2209 Oddie Blvd., Suite 321 Spark, NV 89431 Turn Your Electronics HOBBY into a CAREER Love exploring electronics in your spare time? Imagine what it would be like to make a full-time career of it. The demand for qualified electronics technicians has never been greater. Peoples College can give you the qualifications you need. • Specialized Associate Degree in Electronics Technology • Computer Servicing • Microprocessor Technology Call or write today for a color catalog! There is no obligation and no salesperson will call. Programs in computer programming and computer applications also available. l £ah n "0/|, e 5 1-800-765-7247 Peoples College OF INnFTHNPFNT S T U P I I": S 233 Academy Drive • P.O. Box 421768 • KiSSimmee, FL 34742-1768 Member D.L Peoples Group CIRCLE 176 ON FREE INFORMATION CARD 2 > o I to SO 25 WARNING! CABLE BOX DEALERS Consider the facts before you buy after-market cable equipment An industry standard defines 25% of all after-market cable boxes do not work when first tested... All wholesalers advertise low prices. ..but low prices are not enough. Any price is too high if you're without technical support or quality control. Now consider that your success as a dealer depends on the satisfaction of your customers. Wholesale Cable Supply offers services that are near a defined science. And we guarantee 100% satisfaction. Monthly Special • Guaranteed Low Prices State-of-the-Art technical support Top Quality Tested Products Dealer Market Support WHOLESALE CABLE SUPPLY Low Price is only the beginning TB-3 or SA-3B 10 lot 48 20 lot -43 50 lot -39 100 lot -39 Z-TAC 10 lot - 149 FULLY PROGRAMMA- BLE POWER SUPPLIES. Three power supplies from Fluke offer features de- signed specifically for the system environment, in- cluding single, dual, and tri- ple output configurations; autoranging for full power capability over the full volt- age and current ranges; and extensive protection for the device under test. Each of the power supplies in the PM 2800 series pro- vides a one-box power so- lution for systems by including a GPIB interface, readback, and power mod- ule, and offers front-panel CIRCLE 21 ON FREE INFORMATION CARD programmability for all functions. In addition, the instruments offer a 99-lo- cation internal non-volatile memory, and an autostep function that simplifies the creation of voltage and cur- rent test patterns by auto- matically stepping through the internal memory A software instrument drive for the PM 2800 series is available free of charge. The modules are avail- able in 30V/10A/60W, 60V/5A/60W, and 60V/10A/120W units. The three power modules, when combined with the single, dual, and triple out- put configurations, give the user a choice of 1 1 different models. Device-under-test pro- tection is provided through programmable over-volt- age and over-current pro- tection; a constant current and constant voltage limit to the power delivered to the load; coupled protec- KENWOOD OSCILLOSCOPES AML06 OSCILLOSCOPES H/0 READOUT MOEL C5-S135 40 MHi, Dual Channel . Delayed Sweep - REG. $895,00 SALE (719.95 MODEL CS-5155 :.:'' ?■■■:. J Channel, 6- Trace, Delayed Sweep, REG, 1995, 0C SALE $819. 95 MODEL CS-5165 SO rt J z . 3 Channel . 6-Trace, Delayed Sweep, RE6. S 1095.00 SALE $899.95 MODEL CS-2150 ISO Hi'- , t Channel, 8-Trace, Delayed Sweep . REE. $2395.00 SALE $1*95.95 •JtALOS OSCILLOSCOPES i/REAMUT/CURSORS MQOEL CS-5130 40 KHz, Dual Channel, '-Trace, Delayed Sweep. REG. $1095.00 SALE $B99.95 MODEL CS-41125 20 IIHj, Dual Channel Oscil loscope. REG. $495,00 SALE $349.95 INT WDEL CS-S170 100 HHz, Dual Channel , <- Trace, Delayed Sweep. REG. $1695.00 SALE $1399.95 MXEL CS-5010 100 HHz. « Channel . 10-lrace, Delayed Sweep. RES. $1995. DO SALE $1699.95 W0EL CS- 60211 150- MHz, » Channel, 10- Trace, Delayed Sweep. RES J236! .0. - ' SALE $1999.95 Products International 8931 Bmotvllle Rd. Silver Spring, H) 20910 {800)638-2020 (301)587-7824 FAX# 301-585-540! EASY ORDER FAX LINE (800)545-0058 800-638-2020 I VISA CABLE - TV SIGNAL REMOVERS ■FOR ELIMINATION OF SEVERE INTERFERENCE •FOR -CENSORING- OF ADULT BROADCASTS @> • ATTENUATION - 45 dB TYPICAL • BANDWIDTH - 4 MHz AT S dB POINTS • INSERTION LOSS- 2 dB MODEL TUNING R*HGE Fan CHANNELS pmaaaAND PUCE SHIPPING 23H 50-68 MHz 2.3 [or 6 nwritf ham) 50.300 UHZ 130 HO SHIPPING or C.0.0. CHARGES 48 FM EC-tM MHz 45S(orany FM) 50-300 MHz 130 1417 120- Hi MHz 14(A) 15FB1 15(C) 17(D) SO-100 MHz $30 1822 m-174 MHZ 1»[E) 19(F) 20(G) 21(H) 22(1) 50-400 MHz 330 713 I74-21SMHZ 7. S.9.1 0.1 1.12.13 50400 MHz SIC 3 for $75 - 1 for $200 - mix or match CALL TOLL FREE FOR COD. OR SEND CHECK TOORDER FAST DELIVERY 30 DAY MONEY BACKGUARANTEE (3 FILTER LIMIT) Star Circuits P. O. Box 94917 Las Vegas, NV 89193-491 7 1-800-433-6319 CIRCLE 184 ON FREE INFORMATION CARD tion, which switches off all outputs when a fault in one output occurs; a user-de- finable status register for error reporting; and a standby mode that allows voltages and currents to be set up with no power deliv- ered to the load. U.S. list prices for the PM 2800 power supplies start at $1595 for the sin- gle-output model; $2895 for the dual-output mode!, and $3495 for the triple- output model. — John Fluke Mfg. Co., Inc., P.O. Box 9090, Everett, WA 98206; Tel: 800-44- FLUKE. REPAIRABLE OS- CILLOSCOPE PROBE. The modular construction of Test Probes, inc. 's x 7— x 10 oscilloscope pro- be makes it easy to replace a failed tip, ground lead, probe head, cable, or BNC box — the parts simply screw together for quick re- fi-fW CIRCLE 22 ON FREE INFORMATION CARD pairs. The probe features x 1 and X 1 switchable at- tenuation. Other features include compensation for high and low frequency to optimize pulse response. 250-MHz bandwidth for the xlO mode, 10-MHz bandwidth for the x 1 mode, and a 1.4-nanose- cond rise time. The 10-60- pF compensation range al- lows use of the probe with any scope that has a 1- megohm input. The x /- x 1 os- cilloscope probe costs $72.00 in single quantity. — Test Probes, Inc., 9178 Brown Deer Road, San Di- ego, CA 92121; Tel: 800-368-5719. An ETCHED circuit board from a Printed PAGE in just 3 Hours The ER-4 PHOTO ETCH KIT gives you the tools, materials and chemicals to make your own printed circuit boards. The patented Pos-Neg 7 " process copies artwork from magazines like this one without damaging the page. Use the circuit patterns, tapes and drafting film to make your own IX artwork. Or try the Direct Etch™ system (also included), to make single circuit boards without artwork. The ER-4 is Stocked by many electronic parts distributors, or order direct, postpaid. ER-4 PHOTO ETCH KIT |NJ and CA residents add sales tax] . $38.00 DATAK'S COMPLETE CATALOG lists hundreds of printed circuit products and art patterns. Also contains dry transfer letter sheets and electronic title sets for professional looking control panels. WRITE FOR IT NOW! DATAK Corporation • 55 Freeport Blvd, Unit 23 • Sparks, NV 89431 CIRCLE 189 ON FREE INFORMATION CARD uA in- Home Control i i i i i 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-controlled device, and when used with the Command Center jg/f 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 control. i vsimi Command Center ^^^H Controller © 1990 Heath Company, Benton Harb«r, M] See our full line of home automation products and X-10 modules in the HEATH CATALOG. Call 1-800-44-HEATH for your FREE copy. Order Today $119.95* Use Order Code 601-054 when ordering the One For All System URS-6000. Call Toll-Free 1-800-253-0570 * Ptice docs nor include shipping and handling, or applicable sales tax for MI and CA deliveries CIRCLE 86 ON FREE INFORMATION CARD > O I to 27 Earn Your B.S. Degree in ELECTRONICS or COMPUTERS By Studying at Home Grantham College of Engineering, now in our 41st year, is highly ex- perienced in "distance education" — teaching by correspondence — through printed materials, computer materials, fax, and phone. No commuting to class. Study at your own pace, while continuing on your present job. Learn from easy-to- understand but complete and thorough lesson materials, with additional help from our instructors. Our Computer B.S. Degree Pro- gram includes courses in the BASIC, PASCAL, and C languages — as well Assembly Language, MS DOS, CADD, and more. Our Electronics B.S. Degree Pro- gram includes courses in Solid-State Circuit Analysis and Design, Control Systems, Robotics, Analog/ Digital Com- munications, and more. An important part of being pre- pared to move up is holding the right college degree, and the absolutely neces- sary part is knowing your field. Grantham can help you both ways — to learn more and to earn your degree in the process. Write or phone for our free catalog. Toll free, 1-800-955-2527, or see mailing address below. CO o z e i- o < 28 Accredited by the Accrediting Commission of the National Home Study Council GRANTHAM College of Engineering Grantham College Road Slidell, LA 70460 Try the Eli ectrcnics bulletin board system (RE-BBS) 516-293-2283 The mare yau use it the more useful it becomes. We support 300 and 1200 baud operation. Parameters: SHI (8 data bits, no parity, 1 stop bit) or TE1 (7 d;ii;i bits, even parity. 1 stop bit). Add yourself to our user files to increase yoor access. Communicate with other R-E readers. Leave your comments on R-E with the SYS0P. RE-BBS 516-293-2283 600-WATT LINEAR AM- PLIFIER. Ameritron's AL-81 1 linear amplifier uses three 811 A tubes to deliver 600-watts PEP or 500 watts CW from 160 to 10 meters. (Modification in- structions for 10/12-meter operation are available to those who have valid ama- teur licenses.) The rugged 811 A tubes feature a fast (3-second) warm-up time as well as low replacement cost. CIRCLE 23 ON FREE INFORMATION CARD A Pi-network tuned-input circuit matches the tubes to 50-ohm exciters, for good performance even when the linear amplifier used with fussy solid-state rigs. Tuning is simplified by the use of a vernier reduc- tion drive on the plate con- trol. Pressurized ventilation is used to keep the tubes and power-supply compo- nents at safe operating temperatures. The AL-81 Vs dual illumi- nated meters provide a complete picture of the im- portant operating condi- tions. One of the meters gives a continuous reading of grid current; the second meter is switchable so that it can be used to monitor both high-voltage and plate current. The AL-81 1 linear ampli- fier has a retail price of $599.00.— Ameritron 116 Willow Road. Star- kville, MS 39759; Tel: 800-647-1800 or 601-323-8211; Fax: 601-323-6551. R-E Cable TV Descrambter Article Parts We stock the exact Parts, PC Board and Adaptor tor several articles published in Radio-Electronics magazine on building your own Cable TV Descrambter. February 1984 SB-3 Type 701 Parts Pkg $19.00 Includes all original parts. 7Q2 PC Board 7.95 Original 3X4 etched, drilled and Silk-Screen pc board. 704 AC Adaptor 7.95 T2 to IB Volt DC @ ?00ms. 701, 702 & 704 29.00 All three lor special saving. February 1987 Tri-Mode 301 Parts Pkg. 29.00 includes ait original parts. 302 PC Board 7.95 Original SXB etched, drilled and Silk-Screen pc board. 304 AC Adaptor 7.95 T2 to T8 Voll DC @ 200m*. 301, 302 & 304 39.00 All three tor special savings. Trl-Mode Tutorial. .7.95 26 pages ot in-depth into. May 1990 Universal 901 Parts Pkg, ..,,$49, 00 Includes all parts. 902 PC Board 9.95 Improved 4X7 etched, drilled and Silk-Screened pc board. 904 AC Adaptor 8.95 12 Volts AC @ 350mi. 901, 902 & 904 59.00 AW three tor special savings. Snooper Stopper.. .$39. 00 P rev ent Qescrambfer detection with sneoper stopper/data blocker and protect your privacy, tnctudes free article on CabSa Snooping, Macrovision Kit.. .$29. 00 Macro via Ion now you 300 It, now you do n*t with our macro-scrubber kit. Originally Published in Radio-Electronics . 70 Channel Cable TV Converter $89.95 * 6 Function Infra-Red remote. * Fine Tuning. * Memory & Recall. * Compatible with all External Descrambter. * Channel 3 A 4 switchable outp ut. * 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. O & D Electronics, Inc. PO Box 3310, VISA MC N. Attleboro, Ma. 02761 CIRCLE 179 ON FREE INFORMATION CARD CIE Gives You The Training You Need to At Your Own Pace... & In Your Own Home! Discover Your Career Potential In The Fast-Growing Field Of High-Tech Electronics! If you're anxious to get ahead ...and build a rea/career„.you owe it to yourself to find out about the Cleveland Institute of Electronics! CIE can heip you discover your career potential in the fast growing field of high-tech electronics. A career that will challenge and excite you every day... reward you with a powerful feeling of personal accomplishment... and deliver a level of financial security you may have only dreamed of before! As the leading school in home-study electronics, CIE has helped over 150,000 students in the U.S.A. and over 70 foreign countries get started in this exciting field. To find out how CIE could be helping you... read on... then send for a CIE catalog TODAY! A Growing Need For Trained Professionals! The career opportunities shown here are only a few of the challenging, high- paying careers ycu could enjoy as an electronics technician. You could be the "brains" behind the scenes of an exciting TV broadcast... trouble-shoot life-saving medical equip- ment... design exotic new aeronautics systems... C I E's job-oriented programs offer you the quickest possible path to the career of your dreams! And CIE also features military and union re-training, to build on what you already know. Dozens Of Fascinating Careers To Choose From! Even if you aren't sure which career is best for you, CIE can get you started with core lessons applicable to all areas of electronics. As you advance, CIE makes job opportunities available to you through the bimonthly school paper, The Electron. Consumer Electronics Military Electronics Personal Training From A Renowned Faculty. Unlike the impersonal approach of targe class- room study, CIE offers you one-on-one instructional help 6 days a week, toll-free. Each CIE lesson is authored by an independent specialist, backed by CIE instructors who work directly with you to answer your questions and provide technical assis- vted - tance when you need if , World Headquarters Practical Training... At Your Own Pace. Through CIE, you can train for your new career while you keep your pres- ent job. Each course allows a gener- ous completion time, and there are no limitations on how fast you can study. Should you already have some electronics experience, CIE offers several courses which start at the intermediate level. "State-Of-The-Art" Facilities & Equipment. In 1969, CIE pioneered the first elec- tronics laboratory course, and in 1984, the first Microprocessor Laboratory. Today, no other home study school can match CI E's state-of-the-art equipment. And all your laboratory equipment is included in your tuition cost. There is no extra charge— it's yours to use while you study at home and on the job after you complete your course ! Earn Your Degree To Become A Professional In Electronics! Every CIE course you take earns you credit towards the completion of your Associate in Applied Science Degree, so you can work towards your degree in stages. And CIE is the only school that awards you for fast study, which can save you thousands of dollars in obtaining the same electronics education found in four-year Bachelor's Degree programs! Send For Your Catalog Today! Cleveland Institute of Electronics, Inc. 1776 East 17th St., Cleveland, Ohio 44114 □ YES! Please send me your independent study catalog (For your convenience, CIE will have a representative contact you— there is no obligation.) Apt) Area Cody Phone No. Bill bulletin or educational benefits: o Veteran a Active Duty Mail This Coupon Today! aeos > O X 31 $59.95 INCLUDES 1 GDOD REASONS WHY THIS MULTIMETER IS FOR YOU. 1 AUTO RANGING 2 FULL OVERLOAD PROTECTION 3 DIODE CHECK 4 CONTINUITY CHECK WITH ALARM 5 'HANDS-FREE 1 MEASUREMENT 6 CURRENT UP T0 10 AMPS 7 MEMORY MODE FOR DEVIATION MEASUREMENT 8 0.5% ACCURACY 9 COMPACT RUGGED CONSTRUCTION 10 3 1/2 DIGIT LCD DISPLAY w o z o \3 uu _l UJ g Q < rr 32 Global's Model 735 Digital Multimeter provides a superb combination of high performance, low cost and extremely easy operation. Featuring a full compliment of Autoranging measurement functions including DC Voltage, AC Voltage, DC Current, AC Current, Resistance, Diode Check, and Continuity check. ^ Call toll-free for details 1-800-572-1028 Advanced features such as Memory Mode and Data Hold are provided giving the Model 735 performance normally associated with meters costing twice the price. Don't let the GLOBAL® SPECIALTIES CIRCLE 178 ON FREE INFORMATION CARD low price and compact size fool you, the Model 735 packs performance and value found in all Global instruments. Clearly, the Model 735 is the best value available in it's price category, and is suitable for school, hobbyist and professional users. Acq qj-j Order yours today 1 1 pOUiiHl! A024 Global Specialties 70 Fulton Terrace, New Haven, CT 06512 Telephone: (203) 624-3103. Blnterplex Electronics. 1390. Build this Build a two-way videophon and send and receive video pictures over standard phone lines to and fror~ anywhere in the worldi CHARLES COL nv \S DEMON5TKATEI3 at the 1939 World's Fair, the pic- lure phone was so ine thing placed at the lop of many people's wish list. Unfortunately it re- mained out of reach of the aver- age person — even those who could afford the expense often could not afford the physical space required Tor such a system. However, videophones were re- cently made available to consum- ers at affordable prices, thanks to a new IC that greatly reduces the cost and size of a videophone sys- tem. And. even though it was possible to build a videophone before the advent of this new chip (see Radio-Electronics, August 1982), it's never been easier than now. This article presents a video- phone, or videomodem, that transmits and receives still video frames over the phone line, in high-resolution (200 x 242 pix- el) video with a six-bit (50-level) gray scale. It provides a substan- tially better picture than the low- resolution 96 x 96 pixel units with limited gray scale that you may have seen. The project basically consists of the videophone base unit; you COLBY ■HE |; [ * 1 •' ■ \ ,.*- ■J > can buy it as a bar form or as an assembled and test- ed unit. Among other compo- nents, the board contains one IC that does all of the dirty work. The base unit is connected to a small CCD camera module and Sony Watchman. However, the unit uses standard monochrome NTSC-type 1-volt p-p video for the input and output, so if you al- ready have a standard video cam- era (or camcorder) and monitor, you can use them and save money. To send or receive a video im- age, you do. of course, need two complete units, or at le somebody else who is building one. When you order the PC board from Colby Systems, you will receive a list of users that have Colby videophone units. That will give you contacts to help get your unit up and run- ning and people who you can ex- change pictures with. If you would like to have your name and phone number included on this > x o i 33 list, please let Colby Systems know about it. Uses The videophone has many po- tential uses other than simply showing off the kids to the grand- parents. Such uses might be a commercial artist and page layout person collaborating on a catalog page layout, or perhaps a construction foreman showing a detail on location to an architect in his office half way around the world. An automatic mode makes an- other interesting application possible: the videophone can be used to remotely monitor your house or business, or perhaps a volume gauge on an oil pumping station. By setting up a video camera to view an area, the video- phone's automatic mode could be used to send a new video frame every 38 seconds over an ordi- nary phone line. However, that scheme would work only if you had called an- other videophone and left the phone off the hook while you were away. That would be expen- CAMERA. MODULE N^ /I0E0 •MONITORS^ CO o z O CE 1- O Lii _l LLi o < V BASE V UNIT FIG. 1— THE VIDEOPHONE CONSISTS OF THREE SECTIONS: the CCD camera mod- ule at the top, the video monitor, and the base unit that contains the videophone circuitry. sive to have a phone line in use 24 hours a day — but for certain monitoring situations, the cost *> All resistors are Vi-watt, 5%, unless 14-pin IC socket, one 20-pin IC socket, otherwise noted. one 48-pin IC socket, one 8-pin IC R1— 510 ohms ( x4) 8-pin SIP socket, one 16-pin IC socket, jumper R2— 390 ohms ( x 5) 10-pin SIP wire, project case, video camera, video R3— 10,000 ohms (x 4) 8-pin SIP monitor, coaxial interconnecting leads R4-^t700 ohms (x5) 10-pin SIP (for power and video between base unit R5— 1000 ohms (x7) 8-pin SIP, pin 1 and monitor and camera), solder, etc. common Note: The following items are available R6— 1000 ohms (x 5) 10-pin SIP from Colby Systems Corporation, R7— 1000 ohms ( x 3) 6-pin SIP 2991 Alexis Drive, Palo Alto, Califor- R8— 110.000 ohms (x3) 6-pin SIP nia, 94304 (415) 941-9090. Fax (415) R9— 680 ohms 949-1019, Send check or US postal R10, R19— 6800 ohms money order. Checks take 2-3 weeks R11— 27 ohms to clear. California residents add R12— 2000 ohms 7.25% sales tax. All prices FOB Palo R13— 3900 ohms Alto or Clovls, California. Shipping R14— 8200 ohms charges are UPS ground, continen- R15— 15,000 ohms tal US only, and insurance is in- R1 6— 27,000 ohms cluded. Add $5.00 handling fee to R17— 4700 ohms each order. R18— 180 ohms • Bare PC board (PCB-VP)— R20— 75 ohms $24,99 + $3,50 S&H Capacitors • PMC-VP video controller IC (PMC- C1. C4, C5, C15, C17, C20-^»70 (4.R 16 U7)— S49.99 + S3.50 S&H volts, radial electrolytic • Kit of all other IC's including pre- C2, C3, C9, C18— 100 (iF. 16 volts, radial programmed 1C8 (Kit IC-6)— electrolytic $39.99 l $3.50 S&H C6. C10, C24— 10 ^F. 35 volts, • Kit of all discrete components (re- radial electrolytic sistors, capacitors, diodes, tran- C7, C12. C13, C14, C21, C22, C23— 0.1 sistors, crystal, transformer, jacks, p.F, monolithic switches, LED's, relay) (kit-VPC) — C8— 0.1 |iF, 200 volts, polyester S49.99 + $3.50 S&H C11 — 0.05 (j.F, ceramic * AC adapter (VP-AC)— C16 — not used S1 2.99 ■ $4.50 S&H C19 — 4.7 jiF, radial electrolytic • Kit of all of the above parts (every- Semiconductors thing to build one complete video- IC1, IC2— 7805 5-volt regulator phone base unit, except case) (Kit- tC3— MP7682 A-to-D converter unit)— $169.99 + $7.50 S&H IC4 — LM324 quad op-amp • 240 .- 320 line CCD camera module IC5, IC6— MB81464-12 64Kx4 DRAM (XP-CCD-1)— S299.99 i S5.50 S&H IC7— PMC-VP video controller • Sony 2.7-inch monitor (Sony-2) — IC8— GAL16V8 custom A-to-D filter $129.99 +$4.50 S&H IC9— LM393 low-power voltage • Videophone-to-monitor power & comparator video cable (PVC-M)— $9.95 + $3.50 DN1— 1N914 (x8) diode network (con- S&H tains D1, D3, D9-D13, D16) • Videophone-to-camera power & D2, D4, D5— 1N4001 diode video cable (PVC-C)— $9.95 ■ $3.50 D6-D8, D14. D15— not used S&H LED1-LED4 — miniature red light-emitting • All of the above items ordered at diode one time (Kit-complete) — Q1. Q2. Q5— 2N2222 NPN transistor $599.99 - $13.25 S&H Q3, Q4— 2N3906 PNP transistor • A VHS video tape showing step- Other components by-step assembly and testing, in- FB1-FB9 — territe bead over jumper wire cluding sample pictures — J1 — coaxial power jack $19.95 + $4.75 S&H J2, J6— RCA jack • An assembled and tested version J3 — miniature phone jack of the videophone will be available J4, J 5— modular phone jack as soon as FCC testing and registra- J7— subminiature phone jack tion are completed. Write Colby Sys- J8, J9 — 3-pin header jumper block tems for price list. T1— 600/600 ohm audio isolation trans- The following items are available from former, 1500 volt rating Getty s Electronics, 22018 Frontier XTAL1— 3.57 MHz crystal Road, Clovis, CA 93612 (209) S1— SPST switch 299-7828. S2-S5— momentary pushbutton • Round video camera case (Cam- RY1— SPST relay, 12-volt coil case-1)— $29.99 i $5.50 S&H Miscellaneous: four Va-imh LED stand- • Videophone case with metal bot- offs. PC board, 120 VAC to 12 VDC tom and plastic top (VP-case-1)— adapter, three 18-pin 1C sockets, one $34.99 + S5.50 S&H. might be acceptable. For in- house lines, it might be a conve- nient way to remotely monitor something without running new wires. Another way to do monitoring 34 FIG. 2— VIDEO IS FED INTO J2: It Is then amplified, digitized, and converted to a series of audio tones to be sent over standard telephone lines. is to connect the output of the videophone in parallel with a phone answering machine with no message — or perhaps a short message to tell you which monitoring station you have reached. After the outgoing mes- sage, record 2 or 3 minutes of silence. (You must use the older type of machine that lets you con- trol the end of the outgoing mes- sage.) Then you will be able to use the answering machine for both the announcement function and the off-hook timer, to allow the videophone to output one or more frames of video. Overview As shown in Fig, 1, the video- phone consists of three main sec- tions: the CCD camera module at the top, the video monitor, and the base unit that contains the videophone circuitry. Because the camera module Is mounted on the TVs antenna, and because the antenna isn't needed when feeding the monitor with a direct video input, the camera can be easily pointed in any direction. Take a look at the block di- agram in Fig. 2. The video output of any standard video camera, camcorder, VCR, videodisc, etc.. is fed into J2: it is then amplified, digitized, and converted to a se- ries of audio tones in the range of 1700 to 3500 Hz. That frequency range is low enough to be sent over standard telephone lines, re- corded on a low-cost audio cas- sette tape, or transmitted be- tween two-way radios. It takes 9 to 1 2 seconds to send or receive a still video picture, during which time both phones are silenced. The data being sent are pulse-width modulated with data rates of about 32 kilobits per second. The data transmission rate is about half that of the new r. > o X 35 ISDN system (see Radio-Elec- tronics, May and June 1989), but it works on standard phone lines. Each baud is one pixel, with up to 6 bits of gray scale per baud — 12 bits per cycle are sent since one baud is x h cycle in length. The camera The video camera used with the prototype unit is a pre-as- sembled and tested Chinon CCD module; it consists of two very small PC boards with surface- mounted parts on both sides of each board; it measures 1 x l 3 /ie x 2 3 A inches, and weighs an in- credible 2.1 oz. (60 grams). The camera is shown inside its cir- cular housing in Fig, 3. Included is a fixed-focus, 4.5 mm, F1.8 lens, which is somewhere be- tween normal and wide angle. It provides a good compromise for use in this application; a person's face fills about % of the screen at a distance of Vh to 2 feet from the camera. Depth of field is from 6 inches to infinity, which means that everything farther than 6 inches from the camera will be in focus. The module has a built-in elec- tronic shutter with a range of Vfeo to l /i5,w»of a second. That pro- o z o E t- o 111 1 o < a: FIG. 3— THE CAMERA IS FIXED-FOCUS, with a 4.5 mm, F1.8 lens. The pre-as- sembled and tested unit consists of two very small PC boards with surface mounted parts, and weighs only 2.1 oz. vides a usable picture in light from 2 LUX all the way to direct sunlight. It uses a '/j-inch MOS pickup device that has 80.000 pixels and, in the NTSC format, provides 240 vertical by 230 hori- zontal lines of resolution. The horizontal frequency is 15.734 kHz and the vertical frequency is 59.94 Hz. (A PAL version of the camera module for Europe will be available.) The output is a stan- dard composite video signal — 1 volt p-p into 75 ohms. The camera operates on an in- put voltage of 7 to 12 volts DC at about 75 mA. The videophone base unit provides power for the camera from J3. A jumper block (J9) inside the unit allows either 12 or 5 volts DC to be available at J3. If you use the same camera we did, be sure to set the J9 jumper to the A-B position (12 volts); the B-C position provides 5 volts at J3. Mounted in a circular housing, the camera module attaches to the monitor's antenna with nylon clamps. The mounting arrange- ment allows the camera to be pointed in any direction, which is a lot more versatile than Fixed- camera type systems where the subject must be moved into the field of view of the camera instead of the other way around. The camera module is available from the source mentioned in the parts list. However, if you already have a video camera that puts out a 1-volt p-p standard composite video signal, you are free to use it instead, but you'll be losing the compactness and ease of aiming the camera when you do that. The TV/monitor module The TV monitor we used is an un-modified, off-the-shelf, Sony black-and-white Watchman TV (model FD-250). The unit has a composite-video input jack so it can directly accept the video from the videophone base unit. The picture is surprisingly sharp and clear, but that partially depends on the quality of the camera you use. The monitor attaches to the top of the base unit with a brack- et and a strip of velcro. The bracket attaches to the monitor's rear support foot. The monitor is available from the source men- tioned in the parts list and, more than likely, at a store near you. The base unit The base unit contains the electronics for the videophone. It also contains a double-sided PC board with eight IC's and other assorted parts. The back panel contains an on/off switch and in- put and output jacks for video, power, and the phone line. The front panel contains four push- button switches and indicator LED's. The schematic for the circuit is shown in Fig. 4; let's first discuss how a video image is sent from one videophone to another. The video signal from the camera en- ters J2 where it is coupled by CI and R4-c to the input of IC3, a flash A/D converter. The flash A/D converter is used to convert the incoming analog video into a dig- ital signal. A block diagram of the flash A/D is shown in Fig. 5. The input signal is connected to the non- inverting inputs of 64 com- parators. The inverting side of each input comparator is con- nected to one resistor in a series ladder configuration. The re- sistor ladder is connected to an external reference-voltage gener- ator (IC4, Q3, and Q2), which keeps the input of each com- parator in the chain referenced to a slightly higher voltage than its neighbor. An analog input is ap- plied to the non-inverting input of the comparators. The com- parators that have a reference voltage on their inverting inputs that is greater than the video volt- age at that point in time will switch to a different output state. The outputs of the 64 com- parators are fed into the 64 in- puts of the latches which are enabled by every clock pulse at a rate of 3.58 MHz. At this point the input signal has been converted a group of 64 on-off conditions. The 64 on-off levels are then encoded into a 6- bit byte which is output through a flip-flop and three-state buffer for each of the six bits. An analog input of volts produces an out- put code of 0. An analog input of 1.5 volts produces an output code of 100,000 (with a V^p of 3.2 volts). The 6-bit digital output code of a number between and 100.000 representing a video input level between and 1.5 volts is ther fed into pins 27-32 of IC7, the 36 X3 "J "=; s "tl (1 O r c n w 5" A •.a a <■> 2, *3 •< m o < contr pin IC erted > 30O oiler c thedi to a s ?ai 2 " 5 < ™m? 9 □ fj aV 3 in TJ o w — C o 3 a a X o ? o 5" m o audi Hzr the 0) — *• s tn 30 o c o ton ange prim 9 d -i a a n o < s in t nd fe ry of 3 a. < i m 3 ° rt ID 01 ffi e >— • 3 o 1 i— ) o 15 ■ to 3450- pin 23 to rmer Tl, T (B (0 9£S ess: ^SL^ rr — _. r+ « 3 o o P r* £. ^^ S3 rti co and tele Ylan o.*d o c,oP m ft ra ■ co P 'P rt r n> rs 3 1661. H0HV1AI Join the V) g z o O X to 41 w Q Z 5 F O oj _j W O Q < q: -112,' i 3 <-■ ZENER] -f 4 )-- THI-STffTE BUFFERS ENCODER FLIP FLOPS ■ OFW •j x ,B5(MS61 ^r : r B5 B4 B3 B2 B1 (LSB) CE1 CE2- .J FIG, 5 — THE FLASH A/D CONVERTER is used to convert the incoming analog video signal into a digital signal. The input signal is connected to the non-inverting inputs of 64 comparators. J5. At the start of a transmis- sion, there is a short 3442-Hz tone burst that triggers the re- ceiving videophone to go into the receive mode. Receiving an image When a 3442-Hz tone is pres- ent at pin 24 of IC7, it automat- ically switches the system into the receive mode. The tones com- ing from the phone line at J5 (representing video information) are coupled by C8 to Tl, The sec- ondary of Tl is connected to the differential inputs of IC9. an LM393 op-amp, which amplifies the audio tones and presents them to pin 24 of IC7. The video controller chip (IC7) then converts the audio tones into 6-bit digital words and stores the video frame in digital form in DRAMs IC5 and IC6. The digital data is then output to IC8, a proprietary Colby programma- ble logic array (PAL), which func- tions as a D/A converter and filter. The PAL converts the digital sig- nal back into composite video which is further amplified by Q4 and Q5 and then coupled by C15 to the video output jack, J6. The video format is standard NTSC (or PAL on special order), so it can be fed into any video tape record- er or video monitor. The audio tones containing the video information {available at J5) can also be recorded on an ordinary audio cassette if desir- ed. If you do that, you must at- tenuate the signal out of J5 if you want to run it into the recorder's microphone input. For playback, the signal out of the recorder must be within the videophone's input range of 250 mV to 5 volts p-p. Power distribution A 120 volt AC to 12 volt DC, 1- amp AC adapter (a 220-volt ver- sion is also available) provides power for the videophone, and it is input at Jl. The voltage passes through Dl, a polarity protecting diode, to SI, the main power switch. From there, the 12 volts is applied to 7805 voltage reg- ulators IC1 and IC2: IC2 supplies + 5 volts to most of the circuitry, and IC1 puts out 5.7 volts be- cause of D4 in its ground return path. Jumper blocks J8 and J9 are used to select the output volt- age to power the camera and monitor. If you use the Sony monitor, place jumper on J8 in the B-C position. That will supply 5.7 volts DC at J7; if you use as 12- volt monitor, place the jumper in the A-B position. Maximum cur- rent out of J7 is 450 mA at 5.7 volts or 650 mA at 12 volts. (That also depends on how much power you are drawing out of J3 for the camera power.) If you use the CCD camera module mentioned in this arti- cle, set the jumper on J9 to the A- B position to provide + 12 V to J3 for the camera (the B-C position provides 5 volts to J3). If you use different cameras or monitors, be careful to observe the power ratings of both the AC adapter (which is rated 12V at 1 amp, or 12 watts), IC1 and IC2 which, without a heatsink should not put out more than 55 mA each. The videophone base unit re- quires 12 volts at 150 mA, or 1.8 watts; the CCD camera requires 12 volts at 75 mA, or 0.9 watts; and the Sony monitor requires 6 volts at about 380 mA, or 2.3 watts; the three units total about 5 watts. Other camera/monitor combinations may require the use of separate AC adapters to supply power to them. Of course, when you use separate adapters, you would then lose the ability to turn all three units on and off with the one power switch on the rear of the videophone. Next month That's all we have room for this month. In the meantime, we have provided the list of parts you'll need, as well as places to get them. You might want to obtain everything you need right now. so that next month you'll be able to complete this project. We'll be go- ing over all of the construction details, as well as the hookup and operation of the unit. R-E 42 TURN YOUR PC INTO A UNIVERSAL FREQUENC COUNTER Build a frequency-counter board that operates in a Windows environment in your personal computer. JOEY GRASTY and BILL SCHULZ LAST MONTH WE STARTED TALKING about the PClO's circuitry. So let's pick up where we left off. The pin description and equations for the PAL (IC4), mentioned last month, is shown in Listing 1. Shown in Fig. 3 are two 74HCT374 eight-bit registers (1C9 and IC10) that control opera- tion of the PC10. The registers are of the write-only type; they may not be read back. Register 1 (REG1) controls the source selec- tion for inputs A and B of the OE10 and the prescale used for frequency measurements. Regis- ter 2 (REG2) selects the input source for the pulse-width mea- surement, the pulse-width polar- ity, and hysteresis and gain levels for the input amplifiers. See the PC 10 register map (Table 2) for more details. Input signals to the A and B inputs on the OE10 are selected using 74AC11151 eight- to-one multiplexers (IC16-IC18). The in- put-A multiplexer, 1C16, con- trolled by AbEL2-ASEL0 in register 1, determines which in- put signal drives input A. The output of the multiplexer drives one input of relay RY3, which se- lects either the multiplexer out- put or the output of the 50-ohm amplifier. That circuit is required because the 50-ohm amplifier generates signals that are higher in frequency than the multiplex- er can pass. Relay RY3 is also con- trolled by ANSEL2-ANSEL0, de- coded by IC23-a, the 74ALS12 nand gate, which in turn drives g3. Similarly, BSEL2-BSEL0 control which input signal drives input B with multiplexer IC17, but no relay is required. An AD7528 (IC11) dual 8-bit multiplying digital-to-analog converter (DAC) is used to pro- vide a threshold voltage for each high impedance amplifier. That type of DAC provides only a cur- rent output, so each of the two outputs is converted to a voltage with one section of IC12 (IC12-a and IC12-b), aTL074 quad opera- tional amplifier. Two additional op-amps (IC12-C and IC12-d), configured as adders, convert the unipolar outputs of the first two op-amps to bipolar signals. The 2. 5- volt reference voltage for each DAC is provided by IC13, and AD580 voltage reference. The addition of an edge-detec- tion circuit (Fig. 4) allows a pulse width to be measured. Two 74HCT74 D-type flip flops (ICf _ a and -b) and two 74HC00 nand gates (IC20-a and -b) form rising and falling edge detection cir- cuits: IC20-a provides an active- low pulse, one timebase clock long, each time a rising edge is detected, and lC20-b provides a pulse for each falling edge. A 74HC157 quad two-input multi- plexer (1C21) selects which edge detector goes to Input C or D of the OE10. If a rising-edge pulse is sent to input C and a falling-edge pulse is sent to input D. positive- going pulse widths will be mea- sured. The opposite selection measures negative-going pulse widths. The PC 10 provides a single 50- ohm input amplifier (see Fig. 5), typically used for input from RF circuits. The incoming signal is first amplified by IC25 and IC26, monolithic microwave integrated circuit (MMIC) 50-ohm ampli- fiers, each with a gain of 11 to 20 > DO O T IT) 43 o z s h- o 9 Q < dB. Each amplifier is powered from + 5 volts through a 75-ohm resistor, a 100-(xH inductor, and several decoupling capacitors. Those components supply power to each amplifier and prevent high-frequency signals from en- tering the power-supply rails. In order to provide frequency- measurement capabilities far higher than the input ca- pabilities of the OE10, prescaling has been provided. The MMIC amplifiers drive two cascaded prescalers: a UPB582C divide-by- four prescaler (IC27), and a gen- eral-purpose CA3199E divide-by- four prescaler (IC28). When the two are cascaded, divide-by- 16 prescaling is performed, allowing frequencies above 3 GHz to be measured. Selection of the prescalers is controlled by the prei and preo signals from register 1. Those sig- nals drive an LM339 quad voltage comparator (IC24), with a 2.5- volt threshold set by R15 and R16. If direct frequency measure- ments are required, prei and preo are both set to logic 0. The comparators' inputs are then driven below the threshold volt- age, causing Ql and Q2 to turn off. That causes relays RY1 and RY2 to be deactivated, turning off both prescalers. Diode Dl then routes the amplified signal to a third MMIC amplifier, IC11, be- fore going to RY3, where the sig- nal is sent on to the OE10. An input-bias adjustment potenti- ometer R31 is used to center the output of the MMIC amplifier at approximately 1.5 volts for best performance. If measurements prescaled by 4 are required, prei is set to logic and preo set to logic 1. That causes comparator IC24-C to acti- vate, turning on Ql and RY1. That forces IC27 to begin prescal- ing the signal, deactivates Dl, ac- tivates D2, and routes the output of prescaler IC27 to the MMIC amplifier. Conversely, if measure- ments prescaled by 16 are re- quired, prei must be set to logic 1 and preo to logic 0. That turns on both relays, causing both pre- scalers to start. Diodes Dl and D2 are then deactivated, sending the output of the second pre- scaler IC28 to the MMIC ampli- fier. The PClO's bypass capacitors and unused logic gates are shown in Fig. 6. LISTING 1 DEVICE 20V8 TITLE PC COUNTER BOARD SELECTION LOGIC NAME Bill Schulz; SIGNATURE COUNTER: PIN 1 = A0; PIN 2 = A1; PIN 3 = A2; PIN 4 = A3; PIN 5 = A4; PIN 6 = A5; PIN 7 = IOW; PIN 8 = IOR; PIN 9 = AEN; PIN 10 = S6: PIN 11 = S7; PIN 13 = S8; PIN 14 = S9; PIN 17 = COMP; PIN 18 = DAC; PIN 19 = REG2: PIN 20 = REG1; PIN 21 - OE10; PIN 22 = G; PIN 16 = RT; PIN 23 = RESET: DAC = !A1 & !A2 & A3 & A4 & !A5 & S6 & S7 & S8 & S9 & !AEN; IREG1 = !A0 & A1 & !A2 & A3 & A4 & IA5 & S6 & S7& S8 & S9 & IAEN & NOW & IOR; !REG2 = A0 & A1 & IA2 & A3 & A4 & !A5 & S6 & S7& S8 & S9 & !AEN & NOW & IOR; COMP = !A0 & !A1 & A2 & A3& A4& !A5 & S6&S7 & S8 & S9 & !AEN & IOW& NOR; !OE10 = !A3 & !A5 & S6 & S7 & S8 & S9 & !AEN I !A4 & !A5 & S6 & S7 & S8 & S9 & !AEN I IA0 & !A1 & A2 & !A5 & S6 & S7 & S3 & S9 & !AEN; !G = IA3 & !A5 & S6 & S7 & SB & S9 & !AEN I !A4 & !A5 & S6 & S7 & S8 & S9 & !AEN I !A1 & !A2 & !A5 & S6 & S7 & S8 & S9 & !AEN I !A2 & !A5 & S6 & S7 & S8 & S9 & IAEN & HOW & IOR i !A0 & !A1 & !A5 & S6 & S7 & S8 & S9 & IAEN & IOW & NOR: !RT = RESET I !AO & A1 & A2 & A3 & A4 & !A5 & S6 & S7 & S8 & S9 & !AEN & NOW & IOR; AP10H amplifier board Because the insides of person- al computers are electrically noisy, no high-impedance ampli- fiers are provided on the PC 10. Instead, two high-impedance amplifiers are provided on an op- tional external amplifier board, the AP10H. That board, shown in Fig. 7, contains two identical 100-MHz high- impedance ampli- fiers, each with input attenua- tion, a low-pass filter for measur- ing low-frequency signals, and a variable threshold-level adjust. We will therefore discuss only one of the amplifier circuits. Starting from the input BNC connector (Jl), the input signal is terminated by Rl and R2 and C2 and C3. An attenuation of 20 dB is provided if RY1 is enabled. The signal is then sent through the input-protection circuits (Dl~D4.R4,andR5) into the gate of an RF FET transistor Ql, which acts as an impedance con- verter, providing a low-imped- ance source to the remainder of the amplifier. The signal is then amplified by 20 dB by MMIC am- plifier IC1. Relay RY2, when acti- vated by Q3, low-pass filters the signal to provide noise-free mea- surements of low-frequency au- dio signals. Potentiometer R9 is 44 I css[Gy> - j CSRE62> - ^ TIMEBAS1 > *i — V CM 05 IC1B m 7*»C11161 07 ICI7 7MC11151 H RF0U1 "*> - 3D o X 45 CO o z o I Lil -1 LL ■ 9. a < DC PC 10. The threshold may be changed as required by the user. The LT1016 voltage comparator (IC2) Is capable of operating at frequencies greater than 50 MHz. For better performance, a MAX9689 comparator may be used. Two outputs are provided for each high-impedance amplifier from the LT1016; the true signal and its inverse. The desired out- put can be selected by the user. Both output signals are buffered by two 74LS04 inverters (IC3-f and lC3-a for the inverted out- put, and IC3-e and IC3-b for the non-inverted output) before being sent over a cable to the PC 10, Input control signals from the PC 10 at the DB25 connector PI are also buffered by 74LS04 inverters. Table 3 is a description of the pin assignments for PI. the female DB25 connector that is used to connect the amplifier board to the PC 10. Software The PC10 program, like most Windows programs, has a main window from which all functions of the program are controlled. In the upper-left corner is the control-menu box used to move, resize, close windows, or switch to another program. In the up- per-right corner is the minimize button, which reduces the pro- gram to its OEI icon. The pro- gram name is shown in the tide bar between the control-menu box and the minimize button. Beneath the title bar is the menu bar. which is used to select func- tions that do not appear on the main window. The main window contains the main counter display, a mode-se- lect group, gate/aver age/ resolu- tion select group, and three control buttons. The main coun- ter display shows the results of the last measurement and its units. The mode-select group al- lows the user to choose which of five types of measurements are to be performed. The gate/average/ resolution box allows the user to determine the gate time (fre- quency measurements), number of measurements to average (period, time interval, and pulse width), or the resolution (ratio measurements). For frequency or period measurements, reciprocal TABLE 2— PC10 REGISTER MAP Address D7 D6 D5 D4 D3 D2 D1 DO 00000-10111 OE10 Registers (see Table 1) 11000 DACA (W) DACA7 DACA6 DACA5 DACA4 DACA3 DACA2 DACA1 DACA0 11001 DACB (W) DACB7 DACB6 0ACB5 DACB4 DACB3 DACB2 DACB1 0ACB0 11010 REG1 (W) PREO PRE1 BSEL2 BSEL1 BSELO ASEL2 ASEL1 ASELO 11011 REG2 (W) GAINA GAINB BHYST AHYST SPWI PWSEL2 PWSEL1 PWSELO 11100 MCOMP (R) — — — — — — BCNF MCOMP ASEL2-0 Input Description 000 High Impedance Input A, non-inverted 001 High Impedance Input A, inverted 010 High Impedance Input B, non-inverted 011 High Impedance Input B, inverted 100 Not used, reserved for future use 101 Not used, reserved for future use 110 Not used, reserved tor future use 111 50-Ohm input with prescale BSEL2-0 Input Description 000 High Impedance Input A, non-inverted 001 High Impedance Input A, inverted 010 High Impedance Input B, non-inverted 011 High Impedance Input B, inverted 100 Not used, reserved for future use 101 Not used, reserved for future use 110 Timebase Oscillator (10.000 MHz) 111 Not used, reserved for future use PWSEL2-0 000 001 010 011 100 101 110 111 input Description High Impedance Input A, non-inverted High Impedance Input A, inverted High Impedance Input B, non-inverted High Impedance Input B, inverted Not used, reserved for future use Not used, reserved for future use Not used, reserved for future use Not used, reserved for future use measurements may be selected by activating the reciprocal check box. For frequency measurements, the gate group will be shown. The user can select four gate times. 46 12 11 1 10 J^ PR D Q IC19-b 1 /2 74HCT74 >CLK Q CI 1C20-a 'A74HCOO IC20-b V< 74HCOO T>^ ,r « 10 13 15, I A ZA 3A 1A 1 B IC21 2B 'A74HC157 3B 4B WB G $ IfJC IND FIG. 4— AN EDGE-DETECTION CIRCUIT allows a pulse width to be measured. FIG. 5— THE PC10 PROVIDES a single 50-ohm input amplifier typically used for input from RF circuits. a > 33 O X — * CO to 47 +5V +5V GND GND GND -5V -12V > > > > > > > 34 P1B til! PIL] 32 P1P. •f— "■ ■tl Pll 52 P1N 36 P1D 38 P!F IciO f _Ld2 * 1.015 f J.C17 T L CI 9 T °' 1 C1l-L*T % 0.1 C13_L"T*0.1 C16-LT0.1 C18-LT0.1 C14_L IX 0.1 "" 0.1 *^ I ± Ml * 1 C2C_L T» 0,1 C22--T 0.1 T 0.1 T : 0.1 tr 0.1 T C23 C22-fe'!-°-1 J. C6 _L C8 10.1 C/J-T -' C9 0.1 T 0.1 ]Xc25 ' -L.C27 __ C29 I Xc 3 " 1 ; 5sC33 llToi C26-L'T 0.1 028.1/^0.1 C3O5J5 "T^ 0.1 C32J."^o.i JlL-"Tl — - a iXl "J.1 "T l FIG. 6— HERE ARE THE PCIO's bypass capacitors and unused logic gates. o z o £ H O 111 _l UJ O Q < All resistors are Va-watt, 5%, un- less otherwise noted R1— 2200 Ohms R2, R30, R32— not used R3-R6, R21-— 10,000 ohms, 1 /b watt R7. R1 0—4990 ohms, 1% R8, R9— 10,000 ohms, 1% R11-R14— 20,000 ohms, 1% R15, R16, R21— 10,000 ohms, '/swatt R17, R30— 75,000 ohms, Ve watt R18, R20— 1000 ohms, Vb watt R19— 33,000 ohms, Vb watt R22, R23— 75 ohms, chip resistor R24 — 91 ohms, chip resistor R25-R28— 1000 ohms, chip resistor R29 — 47 ohms, chip resistor R31 — 100,000-ohm potentiometer Capacitors C1, C3, C4— 10 )j.F, 25 volts, radial electrolytic C2— 22 u.F, 25 volts, radial electrolytic C5-C7, C9-C12, C14, C16-C19, C24, C26-C33— 0.1 jjuF, 50 volts, monolithic C8, C13, C15, C20-C23, C25, C51, C54, C59. C64-C66, C68— not used C34, C36— 330 pF, NPO C35— 47 pF, NPO C37, C38—8.2 pF. NPO C39— 2-7 pF NPO trimmer PC10 PARTS LIST C40-C50, C52, C53, C67— 0.001 fj.F, 1206 chip capacitor C55, C56, C58, C60-C63— 0.1 jxR 1206 chip capacitor C57— 47 |iF. 16 volts, radial electrolytic Semiconductors 1C1— 74HCT245 octal tristate transceiver IC2, IC3— 74HCT244 octal tristate buffer IC4— 20L8 programmable array logic (PAL) IC5— OE10 application-specific inte- grated circuit (ASIC) IC6, IC8, IC14, IC15— not used IC7— 74HCT125 tristate quad buffer IC9, IC10— 74HC374 tristate octal D- type flip-flop IC11— AD7528 dual 8-bit multiplying digital-to-analog converter (DAC) IC12— TL074 quad op-amp IC1 3 — AD580 voltage reference IC16-IC18— 74AC11151 eight-to-one multiplexer IC19— 74HCT74 D-type flip-flop IC20— 74HC00 quad NAND gate IC21— 74HC157 quad two-input multiplexer IC22— 74LS86 quad XOR gate IC23— 74ALS12 triple 3-input NAND gate IC24 — LM339 quad voltage comparator IC25, IC26, IC29— MAR6 MMIC IC27— UPB582C high-performance divide-by-four prescaier IC28— CA3199E general-pu rpose di- vide-by-four prescaier D1, D2— HSMP3800 surface-mount pin diode Q1-Q3— 2N2907 PNP transistor 04, Q5— PN2369 NPN transistor Other components J1— BNC bulkhead (R141-306) J2— SMB right-angle PC board connector (R1 14-665) RY1-RY3— SPDT DIP reed relay, 5- volt coil (form 1C) L1-L3— 100 u.H choke P2— female DB25 connector (ITT DBU-25S-AA) P3— SMB plug, cable (R114-082) S1 — 4-position DIP switch XTAL1— 10-MHz crystal Miscellaneous: seven 14-pin IC sockets, four 16-pin iC sockets, six 20-pin IC sockets, one 24-pin IC socket (0.3-inches), one PLCC 44- pin IC socket, one G57 modified stamped PC bracket (Globe Mfg.), one lug (Zierick #334), 6-inch 50- ohm coaxial cable RG187 (0.1 -inch diameter), PC board, solder, etc. 48 IC3-f >k 74LSB4 .12 1 IC3-e J/j 74LS04 .10 3 IC3-a Vs 74LS04 2 "~Jr29 "~i E >5m J. ■ )C3-b Ve74LS04 R23 511} IC3-C V«74LS04_ IC3-d '/« 74LS04 IC6-f Vf 74LS04 \>/e74LS04 rsJ/8 741. tC6-a Ve 74LS04 .2 _- C29 I -IMF R30 51 a !06-e IC6-b \Ve74LS04 psJ/s74LS04 ' ^ S1ti IC6-C Ve 74LSM 6, IC6-d ■,■■»; 74LSC4 24 zo 5i . C21 C23. ■2Z0nF .1 ' . C22 C24. '220nF .1 ' FIG. 7— THE INSIDES OF PERSONAL COMPUTERS are electrically noisy, so there are no high- impedance amplifiers provided on the PC10 board, instead, two high-impedance amplifiers are provided on this AP10H optional external amplifier board. It contains two identical 100-MHz high-impedance amplifiers, each with input attenuation, a low-pass filter for measuring low-frequency signals, and a variable threshold-level adjust. W O z o cr \3 LU I LU 6 D < a: 0.01, 0.1, 1.0, or 10.0 seconds, or use the scroll bar to select any gate time between 0. 1 and 28 sec- onds. For period, time-interval, or pulse-width measurements, the average group will appear. The user can then select 1, 10, 100, or 1000 measurements aver- aged to give the displayed result. The scroll bar can also be used to select any number of averages from 10 to 2800. Finally, for ratio measurements, the resolution group will appear, allowing the user to select resolutions of 100 kHz, 1 MHz, 10 MHz, or 100 MHz, or use the scroll bar for any reso- lution from 1 MHz to 280 MHz. The three pushbuttons are used to start and stop measure- ments. The start button causes AP10H PARTS LIST All resistors are V-i-watt, 5%, un- less otherwise noted R1, R14— 909,000 ohms, 1% R2, R15— 90,900 ohms, 1% R3, R10, R16, R24— 100,000 ohms, 1 /s watt R4, R5, R8, R11, R17, R18— 10,000 ohms, Vb watt R6, R19— 3300 ohms, 1 /a watt R7, R20 — 51 ohms, chip R9, R22— 5000-ohm potentiometer R12, R21— 60.9 ohms, 1% R13, R26-^990 ohms, 1% R23, R27— 220 ohms, 14-watt R25 — not used R2&-R31— 51 ohms, Va-watt Capacitors C1, C9-C11, C19, C20, C23-C26, C29, C30— 0.1 llR 50 volts, monolithic C2, C12— 3.3 pF, chip C3, C13— 33 pF, chip C4, C14— 22 pF, monolithic C5, C8, C15, C18— uP, tantalum C6, C16— 220 pF, chip C7, Ct7, C27, C28— not used C21, C22— 220 p,F, axial electrolytic Semiconductors 1C1, IC4 — MAR6MMIC IC2, IC5— LT1016 voltage comparator IC3, IC6— 74LS04 inverter D1-D8— 1N6263A diode Q1, Q4— 2N4416 RF FET transistor Q2, Q5— 2N2222 NPN transistor Q3, Q6— 2N2907 PNP transistor Other components J1, J2— CP1094U BNC connector, modified RY1-RY4— SPDT DIP reed relay. 5-voltcoii (form 1C) L1-L4— 100 llH choke J3 — male DB25 connector Miscellaneous: PC board, suitable enclosure, 6-foot 25-conductor straight-through cable, solder, etc. TABLE 3— PC10 TO AP10H AMPLIFIER BOARD CONNECTOR Pin Pin Name Description 1,14 VCC + 5V supply from PC Bus 2,5,6 13,15, 18,19 GND Ground from PC Bus 7,20 -5V -SVfrom PC Bus 9,22 AHIPOS Input from high impedance amplifier, not inverted, A input, TTL input levels , 8,21 AHINEG Input from high impedance amplifier, inverted, A input, TTL input levels 3,16 BHIPOS Input from high impedance amplifier, not inverted, B input, TTL input levels 4.17 BHINEG Input from high impedance amplifier, inverted, B input, TTL input levels 12 ALEVEL Comparison voltage level, A input, - 2.5 to 2.5 volts 25 BLEVEL Comparison voltage level, B input, - 2.5 to 2.5 volts 24 AHYST Hysteresis control, A input, LOW hysteresis, 1 HIGH hysteresis, TTL output levels 11 BHYST Hysteresis control, B input, LOW hysteresis, 1 HIGH hysteresis. TTL output levels 10 GAINA Gain control, A input, LOW gain, 1 HIGH gain, TTL output levels 23 GAINB Gain control, B input, LOW gain, 1 HIGH gain. TTL output levels the counter to take continuous measurements until the stop button is clicked. Single mea- surements may be made by pressing the single button. The menu bar has four menus: File, Configuration, Logging, and SetRadio. The File menu has two functions: Exit, used to end the program, and About, which shows some information about the program. The Configuration menu allows the user to set up the PC 10 to take measurements. The Configuration menu has five functions: Input Selection, Cali- brate. Units, Fonts, and Hard- ware. Each function causes a dialog box to appear. The Logging menu has one item. To File, which allows the user to specify what file measurements will be logged. The last menu, SetRadio, has four items: Radio, Thresh- old, Enable or Disable, and Man- ual Set. Each of those menu items are described as follows. When the Input Selection item is selected from the Configura- tion menu, the Input Assign- ment dialog box appears. That dialog box allows the user to set which input amplifier is to be used and what configuration is to be selected. Two groups are avail- able: the Input group and the Ref- erence group. For frequency, period, or pulse-width measure- ments, only the Input group is active. Both groups are active when time-interval or ratio mea- surements are selected. First, the user will select which input (A or B) to use. If A is se- lected, the user has the choice of either the low- impedance ampli- fier built-in to the PC 10 or the A- input high-impedance amplifier on the AH 10 board. If the low- impedance amplifier is selected. Note: The following items are available from Optoelectronics Inc., 5821 N.E. 14th Ave., Ft. Lauderdale, FL 33334 (800) 327-5912, in Florida (305) 771-2050, FAX (305) 771-2052: Complete Kit of all parts to build the PC10, including software, $299; OE10 ASIC, S49; PC10 PC board, S59; software, 55; pro- grammed PAL, $19; assembled and tested PC10, $339; complete kit of all parts to build the AP10H, $179; AP10H PC board, $39; ma- chined and painted cabinet, $49; 6-foot 25-conductor straight- through cable, $20; assembled and tested AP10H, $229. Send SASE for priced out parts list. Include 5% shipping and 6% sales tax when shipped to Flori- da address. 50 FOIL PATTERN for the component side of the PC10 board. the user can choose no prescale, prescale by 4 or prescale by 16. The remaining items are grayed, indicating that they may not be chosen. If the high-impedance amplifier is chosen, the user can choose to include low-pass filter- ing. Signal polarity may be set to positive or negative. Last, the voltage threshold may by changed to any value between -0.5 and +2.5 volts. The Calibrate dialog box ap- pears when the Configuration menu item "Calibrate" is chosen. That dialog box allows the user to calibrate in software the time- base of the PC 10 from an external frequency source. Before select- ing this item, the user must first set up the Input Assignments di- alog for the proper input. The user then enters the reference frequency and hits the OK push- button. The dialog box will disap- pear and a dialog box giving the measured reference frequency will appear after about 25 sec- onds. The user can confirm that measurement by hitting the OK button. The reference frequency will then be stored in the W1N.INI file in the Counter section. The Units dialog box, which appears when the Units item is selected from the Configuration menu, allows the unit of mea- surement to be selected. For fre- quency measurement, Hz, kHz. MHz, GHz, and RPM/CPM (revo- lutions or cycles per minute) may be chosen. For period, interval and pulse-width measurements, seconds, milliseconds, microse- conds, or nanoseconds may be selected. The Fonts dialog box appears whenever the Fonts item is se- lected from the Configuration menu. That dialog box allows the user to select the font and its size to match the user's video config- uration. The selected font is' then stored in the WIN. INI file in the Counter section. The Hardware dialog box ap- pears the first time the program is run, or whenever the Hardware item on the Configuration menu is selected. That allows the user to inform the Windows program what DIP switches are set on the PC10 board. The user checks boxes on the menu to match the setting on the PC10 board. The Logging dialog box, which appears when the lb File item is > 2. C. 1 51 o z o 6 < selected on the Logging menu, informs the Windows program of the file chosen to log measure- ments. The filename of the log- ging file is entered into an edit box. The user can also select if time, date, and units informa- tion is to be stored with each measurement. The Radio Select dialog box ap- pears when the Radio item is se- lected from the SetRadio menu. That allows the user to select which radio the frequency mea- surement will be sent. One radio from a list of more than 10 radios may be chosen, and the choice will be saved in the WIN. INI file in the Counter section. Whenever the Threshold item is selected from the SetRadio menu, the SetRadio Threshold dialog box appears. That allows the user to filter frequency mea- surements so that only valid mea- surements from strong signals are sent to the radio. The user selects how close successive mea- surements must be to each other, and how many consecutive mea- surements must appear before sending the measurement to the radio. The Enable menu item on the SetRadio menu enables the PC 10 to send frequency measurements meeting the requirements set in the SetRadio Threshold dialog box to the selected radio. If send- ing measurements is enabled, the menu item will change to Dis- able, allowing the user to stop sending measurements. The ManualSet menu item on the SetRadio menu sends the last frequency measurement value di- rectly to the selected radio. It by- passes the filtering performed by the SetRadio Threshold dialog box. The program icon (also dis- played on the ABOUT dialog box) is the Optoelectronics, Inc. logo. The software is available as men- tioned in the sources box, and will also be posted on the RE-BBS (516 293-2283) as counter.exe. Assembly The PC10 mostly contains socketed IC's and leaded parts conventionally mounted. How- ever, there are also some surface- mount components in the RF section. Figure 8 shows the parts-placement diagram for the PC 10 board. FOIL PATTERN for the solder side of the PC10 board. 52 FOIL PATTERN for the component side of the AP10H board. FOIL PATTERN for the solder side of the AP10H board. You will notice that, in Fig. 8, certain parts and groups of parts are labeled Gl and G2. This proj- ect can be built for several dif- ferent applications and, depend- ing on the application, certain parts can be left off the board for significant cost savings. To build a 10-MHz-to-2.4-GHz RF frequency counter, all Gl parts must be installed, and G2 parts can be omitted. In that case, the AP10H amplifier is not needed. To build a 10-Hz- to- 100- MHz universal counter, all G2 parts must be installed, and Gl parts can be omitted; the AP10H is required. Other- wise, for a 10-Hz-to-2.4- GHz universal counter, all Gl and G2 parts must be installed and the AP10H is also required. Also note points El, E2, and E3 as indicated in Fig. 8. Normally, for the GO version (all Gl and G2 parts installed), you must jumper point El to point E2 using a short piece of shielded coaxial cable. For the Gl version (G2 parts left out), jumper El to E3, For the G2 version (Gl parts left out), no jumper is re- quired. Install the surface- mount resistors and ca- pacitors first while the PC board is open. If you haven't tried chasing a 1206 sized component all over the place with your soldering iron then here is your chance. While it does require some exper- tise, you will quickly leam the technique. Melt a small amount of solder on one of the PC- board pads where the part is to go. Use a small pick to hold the part in place while heating the solder. Continue holding the part in place while the solder cools. After you are satisfied, solder the other end of the part to the PC board. Do not attempt to move or push against the part after one end has been soldered or you will stress the part and may damage it. The PIN diodes have "DO" on top and look like surface-mount tran- sistors. Solder them in place with the side of a single leg pointing to the top of the PC board. The MMIC's must be in- stalled with the input lead point- ing toward the right (gold fingers down). The input lead is marked on the body (you may need a mag- nifier to see it). Trim the leads to fit on the PC lands between the capacitors. The two remaining leads are bent down to pass 53 C48 C51 hc28^_ IC27| _C44 _ ..A.C41X. LiaJc47L^| IC43 L2" U" C40 Q6T C67, ro 7 R2JRI6 C55Rl3fi22 C56 D2* C60 *D1 — R28 j^- n - C49I C50I C46t Ra5 056. G1 G2 JC29 t R24 uT le i-n-i l ■ ' r i L n P 1024 R1 W s- „ _£. Q4- JC3.6 FIG. 8— PARTS-PLACEMENT DIAGRAM for the PC10 board. See text concerning special instructions for G1 and G2 parts. lllllll.ll l II Till to o z pc F o W _: LU 6 o < FIG. 9— HERE IS AN ACTUAL-SIZE tem- plate for a brass RF shield that goes over the surface-mount input section of the PCIO board. through the PC board where they are soldered. Note that the body of the MMIC will fit in the hole drilled through the PC board. Solder the input and output leads first and then the two ground leads. The three 100-p.H chokes are soldered directly to the PC foil where indicated. Solder the two 8-pin prescaler chips into the PC board where indicated for the best possible high-frequency per- FIG. 10— -THE FINISHED PC10 BOARD. Notice how the brass RF shield goes in place over the input section of the board. ;i-rio-jy4(; — 4 m R30l |R31 + C23| C21-^27 %S C24 1 $11 _J OJ2 ^■fll'l! B16I "J ]C12 C13 I ».K5.. ' C! 1 • IC3 _ IJ C29 IP 9 ., o,n TO IN A OJ1 R5 -■[R4 i R1 ,R2 , 0.4 Dl FIG. 11— PARTS-PLACEMENT DIAGRAM for the AP10H board. "Mi 1 formance. Do not socket the 74HC157 because it will interfere with the BNC input connector. Place and solder the 44-pin PLCC socket with the truncated continued on page 62 54 „ I 1 III WE DISCUSSED ALL OF the operating theory concerning the audio sweep/marker gener- ator. Now lets build the unit. Construction and checkout There are two PC boards in this unit: the power-supply board, which includes the peak-hold cir- cuit, and the main sweep/gener- ator board. Etched and drilled PC boards are available from the source in the parts list. The pro- totype uses a Jameco enclosure type H2507, but any ther- moplastic or metal enclosure with the proper openings for con- trol shafts and jacks will serve the purpose. An internal view of the sweep/generator is shown in Fig. 10. Assemble the power supply/peak-hold board according to the parts layout shown in Fig. 11 and mount near the rear of the en- closure. Three mounting holes in the board match the mounting bosses molded onto the enclosures bottom half. Prior to mounting, solder the transformer leads and 6-inch leads to all the outputs. Those leads can be cut to length later. Mount the trans- former about an inch away from the power-supply section, leaving room for a line cord and fuseholder to pass through the plastic rear panel. If a three-con- ductor line cord is used, connect the ground wire to a closed-loop connector and connect it to the transformer mounting screw. The type of capacitor, C93, used in the peak -hold circuit is critical, and must be a low-leak- age type. Only a polystyrene or a polypropylene dielectric capaci- lor." rated ,0033 \iF to .005 |xF should be used in this applica- tion. The prototype uses a .0047 |j.F capaci tor. You should also use a type 2N4401 transistor for Qll. Substituting an equivalent com- ponent for that transistor will cause unusual almost-peak-hold effects. Play it safe and use only recommended components. All ICs, except IC5, use DIP sockets. Solder all DIP sockets, resistors and capacitors to the main PC board according to Fig. 12. The following instructions will prepare the board for connec- tion of the display and six marker LED's. Cut away that portion of the board where the word "CUT" in- dicates so that the display maybe recessed. Cut precisely up to the thirteen foil fingers that must mate with the connections on the display. Three foil fingers are reserved for hookup wire to be looped through two pads. Press those AUDIO SWEEP/MARKER GENERATOR JOHN WANNAMAKER Build this sweep/marker generator and dis- cover the audio- range frequency response of your amplifier or filter design. three wires flat against their fin- gers and let them extend one-six- teenth inch beyond the board. Solder along the length of the fin- gers. Use the extending wire ends as indexing pins to mate with the holes in the display. Hold the dis- play at a right angle to the board and form solder bridges between board and display to connect all lingers. Hold the PC board with the dis- play along the inside of the front panel to determine where the cut- out for the display should be. Mark points where each of the six LED's must insert through the panel to be soldered to the wide fingers along the board's edge. Use low-current, high-effi- ciency LED's or the CMOS circuitry will not be able to light them. Drill holes for the LED's with a number 33 or 1 . inch bit. Layout the rest of the panel and cut all other neces- sary holes. Make an "L"- shaped metal bracket to help hold the board in place before the LED's are inserted through the front panel and soldered in place. The letters L and S are etched on the board to indicate long and short leads from the LED's. The cathode is the short lead of the LED. Attach the metal supporting bracket to the board with a 4-40 machine screw, A hole is provided between IC11 and IC12. Connect the other end of the bracket to the front panel and solder the LED's for additional support. Add front-panel controls which are closest to the board first, and then complete the connections to the board. It is easier to bring the leads from the controls to the fotl side rather than insert them through holes from the compo- nent side. The 8 volts peak-to-peak sweep output from the sweep/generator may be too much for some scopes to adequately handle. If that is the case, a voltage divider may be needed. A voltage divider can be made by soldering resistors to the sweep jack terminal. Solder a IK resistor from the positive ter- minal to ground and a 4.7K re- sistor in series with the lead wire to the PC board. A long jumper wire must be added to the board to make the connection between the counter input and one end of C16. Solder the leads from the power-supply board to the main board. Com- plete the connections to the on/ off switch and insert a 0,5 -amp fuse. Don't forget to drill a hole in the top enclosure, directly above R9, so that a trimming tool can be inserted after the enclosure is assembled. Now it's time to install the ICs on the main board. The ICs are inserted in DIP sockets, and cer- tain waveforms are monitored at test points in a sequence of stages. That way all circuits and components are properly ad- justed before proceeding to the next step. Check the power-sup- ply voltages before any ICs are in- stalled. The right most pin of each voltage regulator chip is the output. When checked with a scope, any ripple should be less than 1 millivolt. Make sure you unplug the power-supply cord be- fore proceeding to each subse- quent step. Insert IC17, IC18, and IC19 in the counter area and turn the power on. The on-board LED near the crystal should blink di- mly at either 1- or ,1-second inter- vals depending on the position of the sine range switch. If it does not blink, turn off the power and interchange IC17and IC18. Trou- bleshoot the IC by checking the voltage on the appropriate pins first. If an IC is installed back- wards and power is applied, the IC may be damaged. When the LED blinks properly, the frequency display should di- mly indicate 0000, The decimal will probably not be visible in any position of the sine range switch. Clip a jumper lead from either end of any 10-ohm resistor in the power supply to the side of R26 closest to potentiometer R28. Turn the power on. The readout should be 0060, ± 1 Hz, on the two lowest positions of the sine range switch. There may be an occasional erratic readout such as 0067. On the two higher posi- tions of the switch, the readout should be 0006 or 0007. Insert IC14 and IC15 and keep the jumper between the power GROUND CONNECTION POWER SUPPLY V PEAK HOLD AND PEAK HOLD EXTERNAL CAPACITOR MAIN BOARD BOARD GROUND c93 FIG. 10— INTERNAL VIEW OF MARKER/SWEEP GENERATOR. J1 PEAK HOLD INPUT J2 PEAK HOLD OUTPUT -12V oMAIN BOARD + 12V ° COUNTER + 12V MAIN BOARD MAIN BOARD GROUND BRIGHTEN o +5V COUNTER COUNTER GROUND FIG. 11— PARTS PLACEMENT DIAGRAM OF THE PEAK-HOLD and power supply board. supply and R26 in place. Turn the power on. Select the lowest posi- tion of the sine range switch, then select the read mode. Short pin 2 of IC14 to ground with one quick momentary touch. After three seconds the display should brighten and be easy to read. Se- lect either of the two highest po- sitions of the sine range switch. The decimal should be visible be- tween the two middle digits. Set the sweep rate switch to slow be- fore proceeding. Insert IC1 into the PC board. Disconnect only that end of the jumper that goes to the 10-ohm resistor in the power supply and connect it to either end of R2 (R2 is jumped to R26}. Select the lowest position of the sine range switch and turn the power on. The counter should display the frequency of the pulses generated by IC1. Sample the three posi- tions of the sweep rate toggle switch and vary the sweep rate adjustment. You should see the 56 IC18 IC17 I "J -R75- nlj -R7B- C64 -R76 R31-*Ir77' d L 1^ ces-n 03 ' |R ' 9 [55}] -Reo- s s *' /' 20ms/Dlv. + 4V +2V OV -2V -W 2WDIV. 2.7V 2V 1V OV 0.5WDIV 12V 10V 8V 6V 4V 2V OV 2V/DIV. ^ - / 20ms/DIV. 5ms/DIV. 5ms/DIV 2V/DIV. J • / / / ' t ' 2Qms/DIV. + 4V + 2V OV -2V -4V 2V/DIV. II IS' FLA r M M ]VE \ i - ' / / _j 1 20ms/DIV. 3V zv 1V OV i — 1V/DIV. 20US/DIV. 2V/DIV. 4V 2V OV 20)JS/DIV. 1QV OV 2V/DIV. /' t / / 50u S/DIV. 1ZV / / OV FIG. 13— CHECKOUT WAVEFORMS: (a) shows pulses at the end of R2 closest to IC2, sweep rate on low and adjusted to mid-range; (h) shows a ramp at either end of R58, sweep rate on fast and adjusted to mid-range; (c) shows an AC ramp at jack J1. sweep rate on fast and adjusted to mid-range; (d) shows a saw-tooth ramp, at TW, adjusted for to 2.7 volts, sweep rate on fast and adjusted fully clockwise; (e) shows a ramp at pin 13 of IC11 adjusted to fill the CRT; (f) shows a sweep with marker flats at J1, sweep rate on fast and adjusted fully clockwise; (g) shows a sweep with markers and cursor at J1, sweep rate on fast and adjusted fully clockwise; (h) shows the peak-hold output at 6.3 kHz; (/) shows the peak-hold output overdriven at 6.3 kHz; (/) shows the sync pulse at J3, sweep rate on fast and adjusted for mid-range and (fr) shows markers at J4, synchronize the scope with sync, J3, sweep rate on fast and adjusted to mid-range. ramp-like waveform appears. Continue adjusting R16 until the positive peak is no more than + 2,70 volts, as shown in the Fig. 13-d waveform. The positive peak may be flattened. The lower portion of the ramp may become flattened as the adjustment is made. Adjust R9 clockwise until any flattened lower portion of the ramp disappears and the bottom has a sharp sawtooth-like transi- tion at the 0-volt line. Adjust R6 clockwise until any flattened up- per portion of the waveform dis- appears and the top has a sharp sawtooth transition. Adjust the 2V/DIV. 20ms/DIV. sweep rate so that one ramp spans the entire CRT graticule from left to right with the scope adjusted for 5 milliseconds per division in preparation for the next step. Insert IC11 and turn the power on. A positive 12 volts should be present at pin 13 of IC11 with four spike-! ike pulses that fall to zero during each ramp cycle. That waveform is shown in Fig. 13-e. The scope may show five such pulses, as one will be the first spike of a new cycle. Insert IC12 and IC13. Make sure you use a 4538 IC with a BCN or BCP suffix, as others are 2 > O I L CD ID 59 O z o DC o LLI 5 THIS IS THE FOIL PATTERN for the main PC board. not likely to work. Select the run mode, markers on. and in the narrow position. Restore the power. The front-panel marker LED's should flash in a fast se- quence from left to right. Select the narrowest markers, run mode, and the fastest possi- ble sweep rate. Make sure the start adjustment is fully counter clockwise and the stop is fully clockwise. Once the correct fast sequencing is noted, switch to the read mode. Sequencing should be very slow as each LED remains lit for about 15 seconds. As soon as the display bright- ens, press the hold button con- tinually for about one minute to see that it extends the brighten- ing time beyond the usual 12 sec- onds. The same LED should remain lit while the hold button is pressed. Press the skip button several times at about one second inter- vals. A new LED should light as soon as skip is pressed. That will not happen at a slower sweep rate. Connect a digital voltmeter, on the 20-volt scale, between TP1 and ground. Cycle with the skip button until the stop LED lights. Press hold continually while ad- justing R16 for a reading between 2.67 and 2.71 volts. Release the hold button. When the start LED lights, again press hold and adjust R9 to obtain 0.006 volts, using the 2-volt scale. There may be some interaction between R9 and R16. Repeat both adjust- ments as necessary for the prop- er readings of 0.006 volts (start) and 2.67 to 2.71 volts (stop). Insert IC16 and remove all test leads from TP1. Turn the power on. Make sure the start adjustment is fully counter clock- wise and the stop is fully clock- wise. Select the frequency read- out position in the middle range of sine ranoe. Select the fast sweep rate. Cycle for the start LED to tight and press the hold button. Retrim R9 for a frequen- cy readout between 0030 and 0035. Release the hold button. Resistor R9 may need adjust- ment from time to time, due to frequency drift. Select the kilohertz readout po- sition in the middle range of sine range. Cycle until the stop LED lights. Press the hold button. If the readout is between 20. 10 and 60 OPERATING INSTRUCTIONS 1. Plug the marker.'sweep generator in and turn the power on. Allow one half to one full hour of warm-up time in the run mode to minimize frequency drift. 2. Select the fast position of the sweep rate switch, and select the head mode. 3. Select the proper frequency range with the sine range switch. The low range is from 3 Hz to 1 kHz. Both medium positions (m) cover the same range of 35 Hz to 20 kHz. The frequency display will be in Hz or kHz depending on which (m) position is selected. The high frequency range is 3 kHz to 100 kHz. 4. Wait until the unit automatically cycles so that the start LED is lit. or manually cycle by pressing the skip button. 5. When the start LED lights and the frequency readout brightens, press the hold button continuously while adjusting the start frequency. When the start frequency control is fully counter clock- wise, with the middle (m) Hz range se- lected, the frequency readout should be between 0030 and 0035 Hz. If it is not, adjust potentiometer R9 through the hole in the top of the enclosure. Now, adjust the start frequency as desired. 6. Manually cycle the LED's with the skip button until the stop LED is lit. When the frequency readout brightens, press hold and adjust to the desired stop frequency. 7. The start and stop frequencies inter- act somewhat. Repeat both adjustments once, adjusting the start first and stop last. 8. Connect the sweep output of the gener- ator to the X input of the scope. Connect the sine output of the generator to the Y input of the scope. Turn the sine level down counter clockwise. Select the fast sweep rate, rum mode and narrow markers. The cursor should be fully clockwise. 9. Adjust the scope for X-Y operation. A horizontal line with five equally spaced dots, or bright spots, should be seen. Ad- just the scope's X gain and positioning so that the line-ends, with bright spots at each end, exactly match the left and right CRT graticule lines. 10. Adjust the sine level control tor the desired peak -to -peak output voltage de- SWEEP/MARKfcH GENERATOR CONVENTIONAL OSCILLOSCOPE SVNC MARKER O O JN PEAK OUT AUDIO OR FILTER DEVICE IN OUT o— EXT. CH.2 TRIG. CH.1Q O O SWEEP/MARKER GENERATOR DIGITAL MEMORY OSCILLOSCOPE SYNC -O MARKER O — PEAK OUT IN ^HOLD ^ SINE SWEEP AUDIO OR FILTER DEVICE IN OUT -O lUTk il SWEEP/MARKER GENERATOR STORAGE OSCILLOSCOPE SYNC O IN MARKER O PEAK°£L ^ HOLD °^ SINE SWEEP a — AUDIO OR FILTER DEVICE IN -o OUT O- : :: -hMTfH- ■ ■■ " .._ J _ EXT. CH.2 TRIG.) CH.1Q O Q THESE ARE SWEEP/GENERATOR CONNECTIONS tor a conventional, digital-memory or a storage scope. sired. A medium or slow position of the sweep rate control may be more conve- nient to use when adjusting the amplitude. 11. Disconnect the cable from the sine jack and connect it to the peak-hold out (the peak-hold out connects to the scope's Y input.) 12. Connect the sine output of the gener- ator to the input of the device to be tested. Connect the device's output into the peak- hold in of the generator. 13. Adjust the sweep rate, switch, and control for the desired sweep rate. 14. Adjust the scope's volts/division con- trol (Y input) as required. 15. The scope's brightness should be turned down for a satisfactory contour-line display of the response curve. The peak- hold will not operate properly with an input signal of more than 3.75 volts peak-to- peak. Inputs of 0.2 volts to 3.75 volts work best. 21.20, no adjustment is neces- sary. If the readout is only off slightly, adjust R6 and R16 just a little. Recheck to see that the low end still has a frequency reading of 0030 to 0035 Hz. Three poten- tiometers, R6, R9, and R16, all interact, and if a little adjust- ment cannot correct for proper readouts, all the steps after inser- ting IC6-IC9 may have to be re- peated. If the .04 p-F timing capacitor, C20 (four .01 p,Fs in parallel), is not within 1 percent, you may have to find your own adjustment values, or settle for a slightly different range span. The low and high ranges of the sine range have no separate ad- justment; only the timing capaci- tors C19 and C21 can change their ranges. Extra space is pro- vided on the PC board for paral- leling capacitors in order to find a proper range more easily. Insert IC10, a CA3130E. and turn the power on. Select the run mode with a fast sweep, marker on narrow and cursor turned fully clockwise. With the scope on DC input, observe the sweep waveform at Jl, A ramp wave- form interrupted with five flats, or markers, should be seen as in Fig. 13-/". Adjust the cursor control slowly counter clockwise and observe an additional flat moving smoothly among the others. That waveform is shown in Fig. 1 3-g. With the cursor fully clockwise, there should be no ex- tra marker. Set the range of the sine range, SLOW SWEEP RATE , and SWEEP RATE adjustment at mid-position. Se- lect wide markers, place the cursor fully clockwise, and the sine level at mid-position. Ad- just the stop fully counter clock- wise. With the start control initially fully counter clockwise, turn it clockwise three turns. Se- lect the run mode. The display will be dim, but it should indicate a frequency of about 6500 Hz. Set the scope for 0.5 volts per divi- sion and 20 microseconds per di- vision. Observe the waveform at the sine jack, J2, and adjust trig- gering for a steady waveform. Ad- just the two on-board trimmer potentiometers, R27 and R28, for the best sine-wave shape. Those adjustments interact, so you should alternate between them until a good sine-wave shape is achieved. Now, remain triggered on the sine wave but switch the scope's time base to 0.2 milliseconds per division. Turn the start control slowly counter clockwise. The frequency should become lower and may drop to less than 1 Hz. or stop oscillation altogether. Turn the stop fully clockwise. The fre- quency should become higher while the stop control is turning. The waveform should change in frequency from about 30 Hz to 20 Hz over a period of 12 seconds. Adjust R16 if necessary. When the sweep rate switch or control is changed, the sweep from 30 Hz to 20 kHz will either speed up or slow down accord- ingly. Adjust for the slowest pos- sible sweep rate. Connect the sine output to the peak-hold in jack, J6. Reduce the sine level to about one-third the maximum output. Look at the peak-hold out jack, waveform at J5. It should look like Fig. 13-h. Figure 13-i shows the peak-hold output overdriven, causing a downward slope of the flat portion of the waveform. A + 11-volt synchronization pulse should be seen at the sync jack, J3, as shown in Fig. 13-j. The pulse will have an RC time constant-like rise and a fast fall, with a duration of about 70 mi- croseconds. Use the fastest possi- ble sweep rate. Set the scope for 2 volts per division, 50 microse- conds per division, and use { + ) slope triggering. To observe the output at the marker jack. J4, select the run mode, sweep rate switch set to fast, sweep rate adjustment to mid-position and the markers set on and narrow. Synchronize the scope with the output of the sync jack, J3. Adjust the scope's triggering for external input, ( - ) slope triggering, and use a 20 millisecond per division sweep rate. Four markers, consisting of positive pulses, should be seen with a peak value of 12 volts, and a duration of about 15 millise- conds each. That waveform is shown in Fig. 13-k. The marker control should increase the pulsewidth. That completes the checkout. R-E FREQUENCY COUNTER continued from page 54 corner facing the RF section. Place and solder the remaining IC sockets and all other compo- nents. Bolt the bracket to the DB25 connector using #4 hard- ware. Mount the BNC-cable as- sembly to the bracket with the solder lug soldered to the back of the PC board. After checking all solder connections, place the IC's in their sockets. Figure 9 shows an actual-size template for a brass RF shield that goes over the surface-mount portion of the PC10 board. The material should be 0.005-inch brass shim stock. Simply cut out the template (or photocopy it), and tape it on top of the brass stock. Cut along the solid lines using shears, and score along the dotted lines with an exacto knife. Bend down on the score lines and solder the shield in place over the surface-mount section of the board as shown in Fig. 10. Check the operation of the RF amplifiers before installing the brass shield. The API OH amplifier board is relatively easy to assemble com- pared to the PC 10 board. The only surface-mount parts are two MMIC amplifiers that are in- stalled as before. Figure 11 shows the parts-placement diagram for the AP10H board. The completed board must be installed in a suit- able enclosure. Figure 12 shows the completed unit. Alignment and calibration Mechanical adjustment of the 10-MHz timebase is provided by trimmer C9. One of the unique features of the PC 10 is the soft- ware calibration which is avail- able when the program is running. It is really not necessary FIG- 12— THE FINISHED AP10H BOARD. The enclosure is available from the source mentioned in the parts list. to adjust C9 unless you have a desire to. Resistor R31 is the in- put-bias adjustment which can be set to the 4:00 position. The two bias adjustment trim- mers in the AP10H amplifier should be set for maximum sen- sitivity when counting a low-level signal. They can be initially set for mid-range. Installation The PC10 will work in any com- puter that has Windows 3.0 in- stalled, and it requires one three- quarter length expansion slot. Copy the supplied software to your Hard Disk (you may wish to create a PC 10 directory). While in Windows, select the Program Manager and click options under Windows Setup, Options, and Set Up Applications. Follow the instructions to locate and set up the program counter.exe as a Windows application. To run the PC 10 counter, simply select the Counter.exe logo using the mouse and give it a double click. The actual counter input sen- sitivity will vary somewhat de- pending upon the host computer. Grounding, shielding and place- ment influence performance. R-E 62 in ferroelectronics technology promise nearly "ideal" nonvolatile semiconductor memories. TJ BYERS erroelectric ICs — chips that remember WHAT HAPPENS TO VOL ATI LE ELEC- tronic information when the lights go out? Usually it vanishes into thin air, never to be found again. But an old technology with new advancements may make lost data a thing of the past. Ferroelectric technology has long tantalized circuit designers by promising an easy and inex- pensive way of preserving data. Although it's been a long time coming, nonvolatile semiconduc- tor memory using ferroelectric materials that store binary infor- mation can now be made for only pennies more than an equivalent dynamic RAM IC and consider- ably less than an equivalent stat- ic RAM IC. Two leading manufacturers in the ferroelectric field, National Semiconductor and Ramtron Corp. . have developed several fer- roelectric semiconductor devices that retain their memory for up to a year without the aid of an external or internal auxiliary power source. Moreover, the de- vices are exact replacements for popular TTL and CMOS logic ICs, which means that no circuit design changes are required. It's a simple matter of out with the old chip and in with the new. Ferroelectric devices are con- sidered to be nearly "ideal" be- cause of such characteristics as: • Total immunity to power failure. • Resistance to radiation. • Symmetrical read and write cycles. • Low power consumption. • Most operate from a single + 5 volt power supply. We will take a look at how fer- roelectric technology has over- come its traditional problems to become a viable solution to bat- tery-free, nonvolatile semicon- ductor memory. How ferroelectrics work Ferroelectric technology is based on the fact that different insulating materials have dif- ferent dielectric characteristics. Most of us think of a dielectric material as the stuff used in ca- pacitors, such as polycarbonate film or mica, where the electric field, or flux density between the plates of the capacitor is a linear function of the applied voltage. Certain materials, however, ex- hibit nonlinear dielectric charac- teristics, and a few of those leave a residual polarization under the influence of an externally applied electric field, The latter are classi- > —j o I 63 fied as ferroelectric materials. If the electric field is reversed, spontaneous polarization in the opposite direction occurs. Fer- roelectric materials, therefore have two stable polarization states, which can be designed into a "bistable capacitor" with two distinct voltage thresholds. What sets ferroelectric com- pounds apart from other di- electrics is a hysteresis function, or magnetic "memory," that is also characteristic of magnetic devices, such as those used in a coil or a transformer. The name ferroelectric is somewhat of a misnomer because those com- pounds are in no way connected with iron-based materials. The term ferroelectric was derived from their analogy to the hys- teresis function of magnetic de- vices, which can be used to store information. Figure 1 shows the hysteresis loop of a typical ferroelectric di- electric material. That curve is generated by placing a fer- roelectric substance between two metal plates and applying a volt- age. Notice that as the voltage across the material increases, a threshold point is reached where the permittivity of the dielectric suddenly changes. Once the ferroelectric di- electric density threshold has been exceeded, a residual polar- ization charge remains in the di- electric even after the source voltage is removed. It is that re- sidual polarization effect that makes the ferroelectric material effective as a data storage device because the only way to change its state is to apply a reverse volt- age across the ferroelectric mate- rial of sufficient strength to re- verse the polarity of the fer- roelectric charge. Because no external electric field is needed for the fer- roelectric material to remain po- larized in either state, a true nonvolatile digital memory ca- pacitor can be designed for stor- ing logical "Is" and "O's," accord- ing to the polarization state of the material. The stored information can be written to or read from a ferroelectric cell by applying an electric field greater than the threshold (coercive) field to each memory element. Although the process seems simple enough in theory, it took aux DENSITY (B) VOLTS (E) INITIAL FERROELECTRIC ELECTRIFICATION CURVE RESULTANT FERROELECTRIC CURVE FIG. 1— NORMAL HYSTERESIS loop of a typical ferroelectric material. more than 30 years to make fer- roelectrics practical. The prob- lems are many, and not all are yet completely resolved. Some of the frustrating prob- lems encountered in the develop- ment of ferroelectric technology include: • A ferroelectric memory array can be prone to disturbance problems because the coercive voltage is not well defined for dif- ferent compounds. • Thick film ferroelectric com- pounds used in earlier designs required coercive voltages rang- ing from tens to hundreds of volts, which was far in excess of the +5 volt DC supply used in modern day microelectronics. Also, their slow switching speed made thick film ferroelectronics impractical for high-speed read/ write memories (<100 ns}. • Many ferroelectric materials exhibit the phenomenon of fa- tigue, in which the residual po- larization reduces as the total number of polarization reversals increases. • Some ferroelectric materials exhibit the tendency to return to a preferred polarization after re- versal following a long waiting time at the initial polarization. That reaction is known as the "waiting time effect". The biggest problem is that fer- roelectricity is structure-sen- sitive. The crystalline shape, thickness, and resistivity of the material have to be perfect every time for predictable results. Until recently, standard production methods were not available to manufacture reliable, high-qual- ity and inexpensive ferroelectric IC's. Ferroelectric chemistry is also very critical because there's a trade-off between long-term data storage and the number of times the dielectric can be cycled. Fer- roelectric compounds with a long storage time (10 years or more) have very short life cycles (about 1000 cycles), whereas com- pounds with a shorter storage time, such as a year, have a life span that approaches a trillion cycles. Those properties are a function of the ferroelectric blend, and can be changed by varying the proportions of the mixture. As in magnetic materials, once a ferroelectric material reaches a certain temperature, its residual polarization cannot be main- tained, and thus its ferroelectric effects are lost. The temperature above which ferroelectric effects disappear is known as the Curie temperature. Upon cooling, the ferroelectric effect returns, but the data is lost forever. Unfor- tunately, most ferroelectric mate- rials have a Curie temperature that's below the boiling point of FHWGELECTftIC 5™HI %~a nii BIT LINE WORD LINE DRIVE LINE DJRE CTRIC 1 FIG. 2— INTERNAL STRUCTURE of a ferroelectric memory cell 64 oc CLK- DO 01 1 t- I I I J. I 3 i- t> 74CF374 02 D3 l l -> 4 l- V I I I 4 7i- I I I -I B K -O -CLK — D Q ^ -0>CLK — D 3 04 D5 D6 07 i l i 13 >- Y i A 14 i- 17 I- S' I I I 16 >- c > ci K — D QD- -C>CLK — D ao- -0>CLK — -C>CLK — D Q3- -OCLK -D Q3- T t I I ,\ i 20 LINE VOLTAGE SENSOR i 10 1 °i~n G GND t I -| 5 ■4 6 ~C>CLK — D 03- I l I 1 H 12 ! I ,\ h 15 k I I I -i 16 h v t' I I i V i i QO Q1 02 03 04 05 06 07 FIG. 3— LOGIC DIAGRAM of the 74CF374 IC. DRESS- LINES A0< A1< A2( A3< DATA IMC CSO- [A ROW DECODER WEO— % $TL MEMORY ARRAY TPT\ FERROELECTRIC -O TPM > CAPACITOR TERMINALS -Q TPB/ 1 -O CTA S| -O CTB -O CPR -O CPA -O CP6 -O CRA -o CRB CONTROL LIMES DATA OUT COLUMN 1/0 DECODER CONTROL LOGIC ADDRESS LINES FIG. 4— FRAM's" USE A FOUR TRANSISTOR SRAM based cell with PZT capacitors to "shadow" the RAM, thereby eliminating the traditional problem of fatigue. water (100°C) and many require cryogenic cooling. While there are over a hundred different types of ferroelectric materials, most are unsuitable for general use because of one or more of the reasons mentioned above. The most practical fer- roelectric compounds contain lead and/or titanium because they're easily fabricated and have Curie temperatures of over 200°C. Finally, it's ferroelectric The first devices to roll off the National Semiconductor fer- roelectric assembly line are fer- roelectric versions of the 74LS374 IC, an octal D-type flip- flop with tri-state outputs. More complex devices, including a 2K static RAM IC, are working their way through Nationals research and development labs, and should surface soon. The 74LS374 contains eight D- type flip-flops that behave like memory latches. The output of the flip-flops is controlled by the clock. A rising clock pulse trans- fers the data on the input lines to the output lines, where it re- mains fixed until changed by an- other clock pulse. The non- transparent nature of the flip- flops make this IC useful as a buffer latch in counter displays and bidirectional bus interfaces. But when the power is lost, so is the data. In the ferroelectric version of the 74LS374, designated the 74CF374, a ferroelectric capaci- tor is added to the flip-flop. In normal operation, the flip-flop output follows the input with each occurrence of the clock pulse, charging and discharging the ferroelectric capacitor as the logic level changes. When the power is removed, the fer- roelectric capacitor remains in the last state of operation. When power is applied to the IC, the ferroelectric cell forces the flip- flop into the last recorded state, thus preserving the data. The 74CF374S ferroelectric cells can retain data for up to a year, and the one-year clock begins again each time the data in the cells is updated through normal IC oper- ation. The ferroelectric material used in the fabrication of the 74CF374 is based on a perovskite crys- > S o CD CO 65 BL=BIT LINE WL=WRITE LINE PULSED COMMON PLATE FIG. 5— A BLOCK DIAGRAM OF THE FMx 801. This device operates with equal read and write cycle times of 100 nanoseconds and is TTL and CMOS compatible at all inputs and outputs. talline structure with a Curie temperature of about 420°C (788°F), and is a derivative oflead zirconate-titanate (PZT). Unlike previous nonvolatile alternatives, such as EEPROMs, the 74CF374 is fabricated using a process that is virtually identical to that used for standard CMOS logic and memory parts. The only devia- tion is that a layer of insulating ferroelectric material is deposit- ed on the wafer using a three-step masking procedure about half- way through the fabrication pro- cess, as shown in Fig. 2. The internal circuit of the 74CF374 IC is shown in Fig. 3. The ferroelectric layer serves as the basis for the ICs nonvolatile memory. As ferroelectric process- ing techniques improve, how- ever, the three added steps will be reduced to one, decreasing the cost of adding ferroelectric to a device. The procedure is also cur- rently done using economical 2.0-micron CMOS processing, but that's also expected to im- prove as techniques advance. Nonetheless, the 74CF374 still displays excellent 25- ns propaga- tion times with a clock speed of 30 MHz — specs equal to those of the device it mimics, A major concern with any data protection scheme is maintain- ing the integrity of the data dur- ing uncertain power conditions. The 74CF374 has an added cir- cuit that reduces the chances of losing data during power transi- tions. The circuit has a voltage detector that monitors the volt- age of the V (H , supply line. If the supply voltage falls below 3.6 volts, the device is immediately disabled, preventing unwanted glitches from changing the sta- tus of the output lines. If you're interested in obtain- ing app notes from National Sem- iconductor Corp., they can be reached at: 2900 Semiconductor Dr. RO. Box 58090 Santa Clara, CA 95052-8090 Phone: (408) 721-5000 On the other side of the fence, Ramtron Corp., specializing in ferroelectronic reseai ch, develop- ment, and design, has produced a line of ferroelectric random ac- cess memories (FRAM's™). Ramtron's FRAM"" ICs use PZT capacitors to store digital infor- mation. Those digital memory capacitors are integrated into a read/write RAM circuit. CO Q Z o LU _l LU o o < If S1 BESET R1 IK 14, M51 MS2 MR1 MR2 GO Q1 Q2 03 : O>CLK0 IC1 l -Ct>CLKI 74LS9D I? o- MS1 MS2 MR1 MR2 M 01 02 03 1 r^t>CLK0 IC2 I >CL K1 74LS9 ° 13 14 17 19 IC4 74CF374 DO 01 D2 D3 D4 D5 D6 D7 OC T 00 Q1 Q2 03 04 05 0.6 Q7 CLK 12 IS 16 19 .10 n IC3-3 \3 Vj>74LS0B P-J g lC3-b V2 74LS0O IC5 74LS47 BI/RB0 RBI A B C D ^LT _4 5 IC6 74LS47 BI/RBQ 3 RBI a 3 J3 1 2 .10 ,15 14 a :> b y cp d e f B 13 12 11 to 15 14 FIG. 6 — THIS TWO-DIGIT event counter totalizes 5- volt input pulses, with a duration of 15 nanoseconds or longer. The advantage of this circuit is that it doesn't have to be continuously powered. If power is turned off, and then restored, the number of the last count will be displayed on the readout, similar to a mechanical counter. R2-R15 15tKl — A*V R2 R3 R4 R5 PS -NW R7 -Wr R8 AW R9 -WV R10 R11 -wv R12 R13 -wv R14 R15 7-SEGMENT LED / / f I 7-SEGMENT LEO / / I I 66 Figure 4 shows a "shadow" RAM cell which uses four tran- sistor SRAM cells interconnected with two PZT capacitors. That circuit is unique because CI and C2 are activated to store data only when power is lost, and restores data when power is regained. Compared to EEPROM's, Ramtron's shadow RAM architec- ture can store data without power for 10 years, has the ca- pability of >10 9 store/recall cy- cles, and has a life expectancy of >11,000 years at one power loss per hour. Ramtron's demonstration IC, the FMx 801, is a 256 x 1 bit non- volatile SRAM. Non volatility is ac- complished by storing comple- mentary polarization states on pairs of PZT capacitors in each SRAM cell. Those polarization states are retained when power is removed from the device, pre- serving the information. Infor- mation is recovered after power- up by reading those states from the ferroelectric portion of the shadow RAM cell. A block diagram of the FMx 801 is shown in Fig. 5 . The FMx 801 is packaged in a 24 pin DIP Four- teen of the 24 pins are used to operate the IC as a conventional SRAM. Three of the remaining 10 pins connect to separate fer- roelectric devices to distinguish between individual PZT capaci- tors. The remaining seven pins are used with SRAM pins to achieve nonvolatility by store and recall timing sequences. Two of the seven ferroelectric pins, CRA and CRB, provide power and ground, respectively, to the SRAM cell during the read/write and store operations. The re- maining five pins, CTA, CTB, CPA, CPB, and CPRE are control signals that connect or isolate the shadow portion of RAM (fer- roelectric portion) to the static RAM cell. The timing parameters and voltage levels of the seven fer- roelectric pins are critical for data retention. For more information on Ramtron's ferroelectric IC's, you can contact them at: 1873 Austin Bluffs Pkwy. Colorado Springs, CO 80918 Phone: (719) 594-4455 Although FRAM's'" focus on dedicated memory applications, ferroelectric technology can also be applied to logic devices, micro- EXPER1MENTING WITH FERROELECTRICITY Ferroelectric technology is not new, but its recent advancements are. Production of the futuristic 74CF374 IC began only last year, and National Semiconductor is wisely taking a cautious approach to mar- keting these ferroelectric devices. The 74CF374 is now available on a limited basis, and you can become acquainted with this new technology by using the IC in a practical applica- tion, such as an event counter. Presently there is no solid-state equivalent for the venerable sole- noid-driven mechanical counter sim- ply because the battery-powered backup circuits needed to keep the semiconductors constantly powered up are too complex and costly in com- parison. By using ferroelectrics, how- ever, we can make the solid-state event counter a reality. The circuit shown in Fig. 6 is a two- digit event counter that totalizes 5- volt input pulses that have a duration of 15 nanoseconds or longer. The two 74LS90 IC's are binary-coded deci- mal (BCD) decade counters that are the heart of the circuit. Their outputs connect to the inputs of the 74CF374 ferroelectric chip. When pin 11 of the 74CF374 IC goes high, the count from the decade counters is trans- ferred to the IC's output lines, which in turn are decoded by the two 74LS47 IC's for display. The two 74LS00 gates delay the puise going to the 74CF374s clock pin so that the de- cade counter outputs have time to stabilize before they are sampled. The beauty of this circuit is that it doesn't have to be powered up all the time. In fact, when the counter is not in use, you can switch the power off. During the power-off period, the fer- roelectric cells inside the 74CF374 remember the number of the last cou- nt. When power is restored, the last count wili be displayed on the readout just like any mechanical counter. The reset button clears the counter to zero. Although this circuit uses TTL parts, you can use their CMOS equiv- alents with the 74CF374. processors, application-specific integrated circuits (ASIC's), and enhancements for linear cir- cuits. Let's look at some other markets in which ferroelectric devices can be used and where they may replace other compo- nents. The future of ferroelectrics In the short term, ferroelectric devices should find applications in programmable logic IC's, re- placing EPROM's, and DIP switches. Mechanical control- lers, such as event counters and utility meters, automotive elec- tronics, robotics, instrumenta- tion, satellites, communication systems, and programmable ap- pliances are other prime sources for ferroelectric foray. Provided that ferroelectric manufacturing techniques keep pace with burgeoning PC speeds, you'll see more use of ferroelectric memory devices and less use of battery-backed shadow RAM caches. It's even conceivable that all logic IC's may eventually be re- placed with ferroelectric counter- parts. Military applications will find ferroelectric devices particularly attractive because of their radia- tion hardness. In situations where a rad-hardened CMOS memory array would fail, a fer- roelectric array could come through unscathed. Ultimately, ferroelectrics may replace magnetic tapes and driv- es as the primary source of data storage — something both bubble memory and CD drives have tried but failed to do because of such things as cost and technology limitations, R-E Be an FCC LICENSED ELECTRONIC TECHNICIAN! No costly school. No commuting to class. The Original Home-Study course prepares you for the "FCC Commercial Radio- telephone License." This valuable licenseis your professional "ticket" to thousands of exciting jobs in Communications, Radio- TV. Microwave, Maritime, Radar, Avionics and mo re.,, even start your own business! You don't need a college degree to qualify, but you do need an FCC License. No Need to Quit Your Job or Go To School This proven course is easy, fast and low cost! GUARANTEED PASS— You get your FCC License or money refunded. Send for FREE facts now. MAIL COUPON TODAY! T ~c^mm pRODucfions" Tl I FCC LICENSE TRAINING, Dept. 90 J ^ I P.O. Box 2824, San Francisco, CA 94126 ^ ' Please rush FREE details Immediately! ,0 I NAME. i" £ I J 67 1M DRAM TSOP *** ORAM DRAM SEMICONDUCTOR MEMORIES An overview of today's revolutionary memory technology— and a peek at tomorrow's. STEPHEN J. B1GEL0W o z O DC F o LU _l UJ O □ < en STORAGE AND RETRIEVAL OP DIGITAL information has sparked an ex- citing revolution in computers and consumer electronics. You find semiconductor memories in nearly all "intelligent" electronic systems, including car radios, televisions, VCR's, compact-disc players, and computers. Without the on-going advances in memo- ry technology, the high-tech revo- lution would rapidlv grind to a halt. In this article, we will examine several important concepts be- hind semiconductor memory de- vices, including basic tech- nologies, memory organization and configuration, design con- siderations, and applications. Memory types Semiconductor memory de- vices can be classified in one of two ways: permanent or tempo- rary. Although basic operating principles of both are similar, each plays a different role, and each has unique advantages and disadvantages. We will discuss both types in detail. As the name suggests, infor- mation in permanent memory is retained at all times, even after removal of system power. Perma- nent memory is also called non- volatile and read-only memory. Permanent memory is most often used to store fixed program in- structions or numerical con- stants that do not change during the life of a product. For example. personal computers use perma- nent memory to hold the basic input/output system (BIOS) that initializes the computer and pro- vides it with a core of low-level functions. There are four basic types of permanent memory: ROM, PROM, EPROM, and EEPROM. Let's discuss each type. ROM The read only memory (ROM) is the oldest and most straightfor- ward type of permanent semicon- ductor memory. The information that's programmed into a ROM is specified by the buyer, but the ROM itself must be built by the manufacturer. A ROM is relatively inflexible — after its been programmed, it can never be altered. If the informa- tion in a ROM must change, a whole new device must be man- ufactured and substituted for the old ROM, and that is an expen- sive, time-consuming process. Hence the ROM is economically feasible only when used in great volumes for thoroughly debug- ged applications. One advantage of the ROM is its ruggedness. Since the pro- gram is an actual physical part of the device itself, it can withstand relatively large amounts of elec- trical and physical abuse, yet still maintain its contents. The auto- mobile industry uses ROM's ex- tensively in on-board computers. PROM The programmable read only memory (PROM) offers a tremen- dous advantage over the ROM in that it can be programmed by the end user, who is then less depen- dent on manufacturers' lead times. A PROM can be "burned," or programmed, only once be- cause it cannot be erased. The term bum comes from the method used to program a PROM. A factory-fresh PROM consists of a matrix of fusible links. An intact link produces a binary at the selected location: a burned (open-circuit) link pro- duces a binary 1, as shown in Fig. 1. (We'll discuss how to get at a particular location in a PROM later in this article.) To burn a PROM, a special piece of equipment called a PROM burner generates high-en- ergy pulses which destroy the de- sired links to match the contents of a user data file. PROM's are slightly more ex- pensive than ROM's on a per-unit basis, but their flexibility often justifies higher cost. Many PROM's are available through re- tail electronics outlets. ADDRESS BUS ROW SELECTOR BLOWN' LINK ^ [BINARY 1) COLUMN SELECTOR CELL M.AifvX ^=4 ^=4 M GATE DATA 8IT _, SOURCE (\ \ MOS 1 | Jtransister i storage -±- capacitance FIG. 2— IN AN EPROM, CAPACITANCE across the gate-drain junction of a MOS transistor provides storage. FIG. 1— A PROM BEFORE PROGRAMMING consists of a matrix of fused links joining each row-column intersection. Programming blows desired links. EPROM The erasable programmable read-only memory (EPROM) over- comes one of the main disadvan- tages of the PROM: its inability to be reused. After a link has been burned, it can never be restored. By contrast, typical EPROM's can be reliably burned and erased thousands of times. The PROM is built around tra- ditional bipolar transistor tech- nology, which uses both a great deal of power and occupies a lot of space. The EPROM, on the other hand, uses newer metal-oxide semiconductor (MOS) tech- nology, which requires little cur- rent and occupies little space. In an EPROM, information is stored as small packets of charge buried deep within the substrate of the IC, as shown in Fig. 2, An EPROM is programmed much like a PROM. A special EPROM programmer selects an address in the device, places the desired binary information on the data lines, and then pulses the EPROM's program pin. That pulse is what locks the bit pat- tern into the substrate of the chip. To erase an EPROM, it's neces- sary to remove the charges in the IC's substrate. That's accom- plished by exposing the circuit [the die itself] to short-wave- length ultraviolet (UV) light for a prescribed period of time! The ex- citation created by the UV light allows stored charge to dissipate, so the IC gradually returns to its FIG, 3— A FLIP-FLOP is the basic unit of storage in static RAM devices. pre-programmed state. The UV light is introduced into the EPROM through a transparent quartz window in the top of the IC package. Use caution when working with EPROM's, Even though it takes about 20 minutes of ex- posure to a concentrated UV light source to erase an EPROM, some common sources oflight, such as sunlight, fluorescent light and "black-light", may contain enough UV to trigger random charge dissipation and introduce errors in the device. So be sure to cover the quartz window with a piece of opaque material. EPROM's cost more than PROM's, but cost-per-bit is actu- ally lower because MOS tech- nology allows the designer to squeeze several times more infor- mation in the same amount of space. One disadvantage of the EPROM is that it must be phys- ically removed from the system to be erased and re-programmed, EEPROM's The electrically erasable pro- grammable read only memory (EEPROM) is similar to the EPROM, but overcomes its main disadvantage; the inability to program it in-circuit. That fea- ture offers exciting possibilities in applications where software must adapt to changes in the op- erating environment. The EEPROM is no panacea, however. It's slower than other types of memory, and it requires a relatively long time to update the altered data. As a result, EEPROM's are best suited for holding information that changes infrequently. Informa- tion that changes often is best left to the work of temporary memory, the other broad class of semiconductor memory. Temporary memory Information held in a tempo- rary semiconductor memory de- vice can be altered and updated frequently, but will be main- tained only as long as power is supplied to the device. If power fails, memory contents will be lost. That type of memory is usu- ally referred to as volatile memo- ry. It is also known as random access memory (RAM). The name refers to the fact thai any location may be accessed as quickly as any other. By contrast, in a se- quential device like a tape drive. access speed depends on the lo- cation of the desired informa- tion. However, random locations in ROM's. PROM's, EPROM's. and EEPROM's can be accessed with s equal speed. Nonetheless, when § people speak of RAM. they almost x invariably are referring to tempo- ^ rary memory. 2 69 CI 7K STORAGE J_ CAPACITANCE FIG. 4— CAPACITANCE is the basic unit of storage in the DRAM. type has particular benefits and drawbacks. Static RAM Static RAM (SRAM) is the oldest and most straightforward form of temporary semiconduc- tor memory. A typical SRAM con- sists of several flip-flops, or cells, as shown in Fig. 3. Each cell stores one bit of information; multiple cells are arranged in a ADDRESS BUS > ADDRESS BUFFER COLUMN SELECT ROW SELECT J- 1 CONTROL AND REFRESH LOGIC c CONTROL SIGNALS DYNAMIC MOS MEMORY CELL MATRIX DATA I/O BUFFERS DATA BUS FIG. 5— INTERNAL DRAM STRUCTURE. The control/refresh circuitry increases complex- ity but drastically increases storage capacity. ADDRESS LINES ft0- A1- A2- A3- A4- ROW SELECT 32 BITS PRE PROGRAMMED MEMORY CELL MATRIX A5- A6- A7 8 BITS BITS M BITS! 1 OF 8 DECODER 1 OF 8 DECODER column; SELECT READ EN ABLE °- (CH IP SELECT) 1 OF 8 DECODER 1 OF 8 DECODER FIG. 6 — A BASIC ROM consists of row- and column-select circuitry, the memory array, and three-state output buffers. Most electronic processing sys- tems require at least some RAM. w The amount that's required de- 9 pends on the application. A sim- o pie system, such as a program- fE mable digital thermostat, may [f] require only a few bytes of RAM. uj But a computer may require mil- o lions of bytes of RAM. § There are two basic types of £ RAM: static and dynamic. Each two-dimensional array. To access a particular cell, row and coiumn addresses must be set up. and then several control signals must be pulsed. Since data is always available from the flip-flop matrix, the SRAM tends to be a fast device. Its primary disadvantage is lim- ited capacity. Each flip-flop oc- cupies a relatively large area on the IC, so the maximum number of cells is limited. Dynamic RAM Dynamic RAM (DRAM) uses an entirely different technology to accomplish data storage. The key difference lies in the design of the cell itself. As shown in Fig. 4, each cell in a DRAM stores infor- mation as a packet of charge across a MOS transistor, similar in principle to way the EPROM works, but it is unlike the SRAM, which uses a flip-flop to hold one bit of data. To allow frequent updates, each cell must be capable of changing state almost instantly. To allow rapid change, the stor- age capacitance must be ex- tremely low, so low in fact that it cannot sustain its charge for more than a few milliseconds. Therefore each DRAM location must be refreshed about every two milliseconds. If a cell is not refreshed, it will simply lose its data. However, refresh cannot happen by itself; external circuit- ry is required, as well as addi- tional circuitry within the DRAM itself. Fig. 5 shows a block di- agram of the internal structure of a DRAM. The added complexity and cost of refresh circuitry is the main disadvantage of DRAM. On the other hand, DRAM of- fers several distinct advantages over SRAM. Storage capacity is much greater. Common DRAM's provide one megabit (2 2 °) of stor- age, and four- megabit ICs are just over the horizon. In addi- tion. 16-megabit memories are being developed, and 64-megabit DRAM's are on the drawing board. Power is another considera- tion. DRAM's require less current to operate: there are far fewer components per cell to dissipate power. The power savings can be substantial in applications that need a great deal of memory. DRAM's also have a standby mode that essentially disables all functions except refresh. In standby mode, a DRAM requires just a few milliwatts of power to maintain its information. In some cases, the low power re- quirement makes battery backup practical. SRAM's also have a standby mode, but they typically need more than 100 milliwatts of power. Now let's examine some of 70 the technologies used to fab- ricate semiconductor memory devices. Fabrication technologies Every semiconductor memory chip houses sophisticated, sen- sitive microcircuilry. Each min- ute component must be inte- grated deep into the substrate of the chip for die), which itself rests within a hermetically sealed case of plastic or ceramic. The process of circuit integration in- volves a complex combination of optical and chemical processes to form a working IC. Memory de- vices manufactured today are typically made using either bi- polar or MOS fabrication tech- nologies. In addition, a new hybrid of the two technologies, called Bi-MOS, has begun to ap- pear. Although the actual man- ufacturing processes of these kinds of devices are too involved to cover here, we can review the characteristics and uses of those technologies. Bipolar technology The bipolar transistor (with emitter, base, and collector) was the first component successfully integrated into a semiconductor wafer in the form of the TTL IC. Many simple logic functions could thus be synthesized easily and efficiently The resulting low cost and high availability made TTL a mainstay of digital logic design through the 60 s and early 70s. Even to this day TTL re- mams a cornerstone of basic log- ic design. When memories were needed, TTL was the obvious choice. Although there are several SRAM chips in the TTL family (notably the 74S200 and 74S201), TTL suffers from sev- eral major drawbacks that se- verely restrict the capacity of bipolar SRAM. First, bipolar logic requires a relatively large area on the chip for each logic gate. Many gates are needed to build a SRAM, so space is depleted rapidly. In addition, bipolar logic requires significant operating current per gate. Since current ultimately translates into heat, the number of cells is limited even further. Size and power re- straints usually limit the number of bipolar memory cells to fewer than 1000 bits. "SELECT A6 A7 A8 A9A1QA11 -READ/WRITE DATA PIN FIG. 7— THE BASIC SRAM is more compli- cated than a ROM because ol the addition of a reaD'Write line. MOS technology The development of MOS tech- nology is largely responsible for the incredible advances in high- tech electronics since the late 1970s. The materials and chemi- cals used in MOS fabrication are different from those used for bi- polar fabrication, but the process is fundamentally the same. The most familiar MOS family is com- plementary MOS (CMOS), but there are many variations, in- cluding PMOS, NMOS, VMOS, DMOS, and HMOS. CMOS, NMOS, and HMOS de- vices are the most widespread variations of MOS technology in use today CMOS has been used extensively in memories, and to produce a family of devices that is functionally similar to the TTL family. CMOS dissipates far less power than TTL and can run on a much wider range of supply volt- age (3-15 volts DC). N-channel MOS (NMOS) technology is used to produce memories that are fast, dissipate little power, and can fit many components on a chip. Although early devices re- quired several supply voltages, modern NMOS IC's operate from a single 5-voIt supply. High-per- formance MOS (HMOS ) is an NMOS variation that's used in modern high-speed low-power microprocessors. In spite of their obvious advan- tages, all MOS devices suffer from one key weakness: they're extremely sensitive to static elec- tricity. There are important pre- cautions that should be taken. Be sure to follow manufacturers' guidelines for handling MOS de- vices. Memory operations To the external world, the or- ganization of a semiconductor memory device appears as a se- quence of locations. Each loca- tion may have 1, 4, 8, or some other number of bits, but re- gardless of the number of bits per location, each location has a unique address. The number of unique addresses depends on the number of address lines. If there are 8 address lines, then there are 2 8 or 256 addresses. Al- though externally a semiconduc- tor device appears to have a sequential organization, inter- nally the cells are arranged in a square. The relationship between the number of physical cells (bits) and the number of logical loca- tions (addresses) depends on the number of bits per address. For example, a memory IC could have 1 megabit of cells arranged as lxi megabit, as 4x256K, or even as 8 x 128K. Internal decod- ing circuitry varies depending on how the organization is to appear externally. For example, Fig. 6 represents a simple ROM. The format of the ROM is 256 addresses with four bits per address. The memory ar- ray is a 32x32 square, giving 256 addresses. And for 256 ad- dresses the chip requires eight address lines (2 s = 256) to identi- fy each location uniquely. The lower five address lines (AO— A4) select one of 32 possible rows (2 5 = 32). The upper three (A5— A7) select one of eight col- umns (2 3 = 8). There are four 1- of-8 decoders, so four columns (one from each group of eight) will be active for each selection. After a valid address is pre- sented to the address lines, the data bits at the intersections of the selected row and columns will be sent through the respective 1- of-8 decoders to several three- state buffers. If the read enable signal is brought low, the data present at the buffers will be de- livered to the ROM's output. But when read enable is high, the high impedance of the three- state buffer will simply discon- nect the ROM's outputs from the circuit. 3 SRAMs, along with PROM's, £ EPROM's, and EEPROM's, are g more sophisticated. Figure 7 £ shows a simple SRAM organized S 71 w o z o as 4096x1, Addressing is sim- ilar to the ROM in the previous example but, in this case, there are 12 address lines that provide 2 12 or 4096 (4K) addresses. One bit of data is available at each ad- dress location. A read/write control signal de- termines whether data will be read from or written to the IC. If r/w is logic 1, data will be read from the cell. If r/w is logic 0, data will be written to the cell. Tb read a bit of data, a valid address must be supplied, r/w must be high, and the chip se- lect input must be low. To write a bit of data, the same conditions apply except that r/w must be low. The timing relationships be- tween the signals at various pins can be critical, depending on the circuit. Timing considerations Today's generation of RAM IC's has been designed to operate at high speeds, so timing charac- teristics for address, data, and control lines are important. There are several important pa- rameters that we will discuss. Access time specifies how long it takes after addressing a specif- ic location before valid data ap- pears at the IC's output. A slow memory device may have an ac- cess time of as much as 450 nanoseconds, while a fast device might access data in as little as 25 nanoseconds. Common mem- ory devices today have access times of about 100-150 ns. As a rule of thumb, the faster a memo- ry device is, the more expensive it will be. Settle time specifies the amount of time that must pass after setting up the address, data, and chip select signals, be- fore the r/w may be pulsed low to write data into the IC. In addition, the write pulse must be held low for a minimum amount of time to ensure that the data is accepted into memory. That is the duration of the write puise. The address, data, and en- able signals must be held steady for a minimum time after the write pulse; that period is called the hold time. Those timing parameters apply to SRAM's; DRAM's have even more intricate timing require- ments. Although the basic prin- ciples of reading and writing are RAS Q 'CAS ° CONTROL LOGIC REFRESH CONTROL R/W CHIP SEC ° / J COLUMN SELECT r , ,. DATA PIN V DATA BUFFER I/O , i ' MULTIPLEXED ADDRESS LATCH ROW SELECT DYNAMIC MOS MEMORY CELL MATRIX 1 MEG x 1 r\ ADDRESS \ BUS / A0-A9 * (A10-A2O) FIG. 8— DRAM KEEPS PIN COUNT LOW by multiplexing address lines on half the ex- pected number of pins, cas and ras signals strobe low- and high-order address lines into the IC as necessary. 16 +5V IC1 74138 YO Y1 / Y2 Y.3 o— ex Y4 V YS Y6 Y7 15, 14. 13 12 10 13 Ffl 14 R" 10 bo Ai bo R3 6 O 6 o A3 A2 A1 AO V ADDRESS LINES R-l -O- -o- R5 R6 R7 -f -+v $ m 4.7I +5V R8 7K BO Ao Bo > BO A6 BO Ao f 02 1C2 74157 D1-D4 1HZ70 - ROWO - R0W1 - R0W2 - R0W3 - R0W4 - R0W5 - R0W6 -R0W7 + 5V Hf 15 n D1 t DO DATA LINES NOTE: WITH DI0DE=L0GIC WITHOUT DI0DE=L0G1C 1 FIG. 9— BUILD AN EPROM EMULATOR from two TTL IC's, eight resistors, and a number of germanium diodes. Place a diode across each row-column intersection that is to be a logical 0. similar to those for the SRAM, there are some extra features and parameters that must also be considered. The first involves memory ad- dressing. As discussed earlier, DRAM's can provide millions of bits on one device. For example, addressing 1 megabit (2 20 ) would require 20 address lines. It's pos- sible to build an IC with 20 or more pins, but to save space and reduce pin count, several address lines are multiplexed on a single pin. Figure 8 shows the block di- agram of a I-megabitx 1-bit DRAM. Note that only ten address lines enter the IC, so you might think that you could access only 2 it} (1024) locations. In fact the 20-bit address is broken up into two parts, each of which is sup- plied separately. The lower ten bits select the desired row in the memory array, and the upper ten 72 bits select the desired column. The row-address lines are strobed into the IC by pulsing the row address strobe (ras) input, and the column-address lines by pulsing the column address strobe {cas) input. External cir- cuitry must ensure that the prop- er set of address lines is applied to the IC before pulsing a strobe input. After the IC receives the full ad- dress, GHiPSELiiCT and r/w maybe set up, as with an SRAM, to read or write data. The access, setup, and hold times apply to DRAM's as well. Refresh As mentioned earlier, DRAMs require periodic refreshing, oth- erwise their stored charge will dissipate. There are several ways of refreshing a DRAM system, all of which use the ras and cas inputs. The simplest method is called RAS-only refresh. It in- volves holding cas high, which in turn holds the output in a high- impedance, or disconnected, state. The refresh circuitry then selects each row in turn, pulsing ras low for each row as it is ad- dressed. It does not matter whether all rows are refreshed in one sustained burst, or one row between, for example, read or write operations. As long as a cell is refreshed in time, its data will remain intact. Hidden refresh is a variation on RAS-only refresh in which cas is held at logic (for example, valid data is maintained on the output) while rows are selected and refreshed. Depending on system timing, cas may be held low for several microseconds, during which several rows may be refreshed. There are other variations, but all refresh circuits add a fair amount of complexity to a cir- cuit. Fortunately, however, there are refresh-controller IC's for many different DRAM sizes and configurations. Those IC's reduce cost, increase reliability, and de- crease required PC board space. EPROM emulator You can easily assemble your own hand-made "EPROM" using two common TTL IC's and several Germanium diodes. Figure 9 shows the schematic for a 16 X 4 memory circuit. It's loosely called CHIP SELECT LOGIC CHIP SELECT ADDRESS" BUS + V D1„ AQ-A11 zw READ/WRITE * m Hi Z147 D1„ TTT FIG. 10 — BLOCK DIAGRAM OF A 4K x 4 static RAM array— parallel memory IC's increase bus capacity. an EPROM because it can be re- programmed at any time by rear- ranging the diodes in the matrix. Although the circuit is unsuita- ble for high-performance or mi- croprocessor-based applications, it can be used to supply pre-pro- grammed bit patterns to discrete logic circuits. It also provides an excellent demonstration of basic memory operation. There are eight rows and eight columns, yielding 64 bits of memory. Two demultiplexers al- low access to a particular memo- ry cell. One demultiplexer de- codes the row and one decodes the columns. A 74138 l-of-8 de- coder selects the row, and a 74157 quad two-input multiplex- er selects the columns. Address lines A1-A3 drive the 74138 to select which one of eight rows will be pulled to ground. The col- umns are arranged in pairs; ad- dress line AO determines which member of a pair is connected to the output. The 1N270 diodes determine the bit pattern in the circuit. Ger- manium diodes are used because of their low forward voltage drop (0.3 volts); silicon diodes have a higher voltage drop and will not work with TTL IC's. Every column is pulled high via a pull-up resistor. If a diode is ab- sent when a particular row is se- lected, the column will provide a 5-volt output. However, if a diode is in place, it will be forward bi- ased via the pull-up resistor, through the 74138, and then to ground. The corresponding out- put thus becomes a logical 0. For example, if address 0000 is selected, 74138 output yo (row 0) is connected to ground, and all 74157 inputs are connected to the B position. Because there are diodes connected to each the B inputs in row 0, the output would be 0000. If the address was 0001, row remains selected, but the 74157 inputs are switched to the A position. The A cells have no diodes, so all outputs would be high (1111), Parallel memory Semiconductor memories (both temporary and permanent) can be placed in parallel to in- crease the number of data bits available per address, as shown in Fig. 10. The circuit is built from several 2147 SRAM's (4096 x l). By connecting the ad- dress and control lines in paral- lel, the same address in all IC's will be selected simultaneously. The data bits, of course, are kept separate. You could just as easily placeS, 16, or 32 IC's in parallel to create 4K x 8, 4K x 16, or 4K x 32 memory blocks. Conclusion Memory is an integral part of the high-tech revolution. Even the most basic processing circuit would be useless without some sort of memory to store variable data. As you can see from our com- parison of the many different per- manent memory devices, there are distinct advantages and lim- itations to each type. What you choose depends on your individ- ual needs— the ROM is inflexible but rugged, while the PROM can be programmed by the user, but only once because it can't be eras- ed." The EPROM can be pro- grammed and erased over and ^ over again but uses a lot of power > and space, while the EEPROM o can be programmed while in cir- ^ cuit, but is slow. R-E 8 73 AUDIO UPDATE Transfer Functions Part II: Answering a letter of protest LARRY KLEIN o 2 o EC LLI 6 < As someone who doesn't even like to fish, I seem to spend an awful lot of time opening cans of worms. My most recent foray into decanting annelids was my dis- cussion of transfer-functions and Bob Carver's misadventures with Stereophile magazine. In a letter to this magazine, Stereophile editor John Atkinson took exception to sev- eral of my remarks. (See this month's Letters column.) I questioned Bob Carver on some of the disputed facts of the case. It is a "case" because Stereophile origi- nally sued Carver for unauthorized re- printing of a negative review of one of his amplifiers — along with several laudatory reviews of the same ampli- fier. Carver's idea was to invalidate Stereophile'^ negative evaluation by contrasting it with several other very positive reviews from other publica- tions. When Stereophile sued Car- ver, he countersued. claiming, in effect, that for several years Stereophile had continuously and un- fairiy disparaged him and his amplifier products. Since I had not been involved in the chain of events and my knowledge of what occurred was based on a few conversations with Bob Carver and an incomplete collection of Stereophile, Atkinson's letter led me to wonder if I had gone factually as- tray in some areas. I faxed a copy of Atkinson's letter to Carver asking for his comments. At the major points where Atkinson "corrected" me. Carver commented that Atkinson's versions of the events were "simply not true." Who to believe? The straight facts One of the things that I didn't learn in kindergarten is that people — in all honesty — tend to remember and/or interpret events in a way that fits into their preexisting world view. So when I'm forced to choose between alter- nate views of an event, I tend to sup- port the one that makes objective sense to me and whose advocate has the same way of looking at the world as I do. I've known John Atkinson since the days when he worked for the Brit- ish publication Hi-Fi News. I watched the publication under his direction abandon rationality and take its read- ers on an audio "Magical Mystery Tour." frequently promoting products and technologies that lacked any ra- tional technical basis. An example: HFN unashamedly promoted a metal brick "Rux Dumper" that purported to improve the sound of an amplifier when simply placed upon the ampli- fier's metal cage. For me this casts doubt on their overall good sense and seriousness. When Atkinson came to Stereophile, his approach dovetailed neatly with that of its publisher. So although he can talk a good scientific line, his editorial approach and prod- uct evaluations at Stereophile reflect a basically mystical approach to the world of audio. I won't say that I haven't had dis- agreements with Bob Carver. But our arguments have involved his use of technically inappropriate names for his usually innovative circuits, his sensitive ego, and his sometimes self-defeating promotional efforts. Nevertheless, I've always been terri- bly impressed by Carver's design genius and technical rationality. For those reasons. I tend to accept Car- ver's point of view rather than Atkin- son's in regard to the facts in question. Some of the truth of the FIG. 1— THE CARVER SILVER SEVEN POWER AMPLIFIER can deliver 375 watts into an 8- ohm speaker load from 20 Hz to 20 kHz with less than 0.5% total harmonic distortion. 74 matter will undoubtedly be incorpo- rated in the sworn legal depositions given by the two parties involved in the lawsuits. Flawed evaluations I may have misrepresented the ex- act nature of Stereophile's reevalua- tion of the Carver Challenge. Their position seems to be that Carver in 1985 did accomplish what he origi- nally claimed he would- — make his $700 M-1.0 solid-state amplifier sound identical to Stereophile's $5,000 Conrad-Johnson mono tube amplifier. However, in 1987 Stereophiie proved to their own satis- faction that Carver could not dupli- cate his hand -tweaked prototype in production, despite his ads that claimed he had. They did that by com- paring a production-line M-1.0t ("t" for transfer) amplifier with their origi- nal tube reference unit. The flaw in that procedure is ob- vious to anyone familiar with tube technology. There's a very high prob- ability that in the years between the two comparisons, the parameters of the reference amplifier's output tubes shifted sufficiently to produce an au- dible difference during critical A-B lis- tening tests. The correct testing approach would have been to compare Car- ver's production-line amplifierwith his original hand-modified unit. Although Stereophiie had access to the origi- nal unit, they somehow, for some rea- son, did not get around to making that critical comparison test. A final word I stand by my original comments on the cause of the controversy If by making essentially minor modifica- tions on a $700 transistor power am- plifier Bob Carver can cause it to sound indistinguishable from a $10,000 (for stereo) audiophile tube amplifier, then the whole rationale for esoteric high-end audio is obviously Carver has written a 30-page "white paper" explaining his thinking on transfer function-modifications and other technical matters. Priced at $2.00, it is available postpaid and free of charge to readers of this mag- azine. Send your name and address to: Carver Corporation, Dept, R-E, P.O. Box 1237, Lynwood, WA 98046-1237. called into question. And when a magazine's editorial content (and ad- vertising revenues) are based on high-end mystique, there seems to be sufficient reason for them to have second thoughts on the Carver Chal- lenge. But aside from the motivations of all the parties involved, we still have the problem of how to determine the objective facts of the case. I don't know the answer to that one, except to say that I trust Carver's motivation (and science) over Stereophile's. There's one aspect of the matter that, I must say, leaves me flab- bergasted. I won't directly quote Stereophile's publisher (for fear that he'll sue for copyright infringement) but his final editorial words on the controversy bemoan the fact that Carver's best design effort was nothing more than a sonic copy of some other manufacturer's amplifier. And in the Letters column, some of the magazine's readers were out- raged that Carver could mimic the sound of another designer's amplifier without permission. The implication was that the sound was the result of some engineer's hard work and care- ful listening, and Carver was stealing 1 1; \k\ v«n CLEANING/MAINTENANCE/REPAIR EARN UP TO $1000 A WEEK, WORKING PART TIME FROM YOUR OWN HOME! 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FRE£ mFORMAT10N CALL TOLL-FREE 1-800-537-0589 Or write to: Viejo Publications Inc. 5329 Fountain Ave. Los Angeles, CA 90029 Dept. RE Made in the U.S. A. Building the best DMM for the money is no aeddent The new RMS225 was carefully designed to give you what you wanted at a price you could afibrd. Visit your local distributor today and you'll agree the choice is obvious. CIRCLE 186 ON FREE INFORMATION CARD Fluke Model 77 Beekman Industrial HMSK5 3-Vi Digits 4 Digits 3,200 Counts 10,800 Counts 0.3% Accuracy 0.25% Accuracy Touch Hold* Prone Hold™ 31 Segment Analog Bar Graph 41 Segment Analog Bar Graph 2,000 Hour Battery Life 1,000 Hour Battery Life 10A Range (ruswi 10A Range O X CO CO 75 CO O z o DC t- o ui _i hi o Q < cr 76 a valuable property. I look at the matter somewhat dif- ferently. Carver's original design be- fore modification was essentially distortion-free and linear. And its fre- quency response remained flat with virtually any speaker load it was likely to be connected to. The tube ampli- fier that Stereophile supplied had in- put and output impedances that varied with frequency, which resulted in small (±1 dB) frequency- response variations. The specific locations of those variations were somewhat de- termined by the impedance charac- teristics of the particular speakers it was connected to. In my view, the reference ampli- fier's performance was mildly flawed — but in a way that appealed to Stereophile's critical listeners. Car- ver's modification of his amplifier con- sisted of accurately duplicating those existing flaws! When I originally questioned Car- ver on this, he said somewhat ruefully that the sonic differences were es- sentially trivial, and implied that this was his chance to gain credibility with the high-end crowd. I predicted that it wouldn't work because his amplifier wasn't expensive enough to appeal to devout audiophiles. When this turned out to be true, Carver de- signed his own amplifier reference standard — the super-audiophile Sil- ver Seven, shown in Fig. 1 . A no-hold-barred, cost-no-object exercise, the $8,750 two-chassis (but single channel). 350-watt tube amplifier is replete with a plethora of audiophiie excesses such as the use of 14 output tubes, audiophile-ap- proved capacitors and resistors, gra- nite-base shock mounting, solid silver internal wiring, oxygen-free wire in the power transformer pri- mary, silver in the secondary, and so forth, A Silver Seven stereo setup will cost you $17,500. Needless to say, the Silver Seven garnered rave re- views. Carver duplicated the Silver Seven's transfer function in a 550- watt solid-state mono amp available For a mere $1 ,000 and, subsequently, in a series of lower-priced stereo units. I'm sure that the $17,500 "Sil- ver" amplifier (and its lower priced brethren) sound great, but I wonder if they sound any better than Carver's original unmodified M-1.0? R-E CHEMICAL SOLUTIONS FREE CHEMTRONICS CATALOG! Comprehensive new source for over 200 products used in electronic manu- facturing and field service. E-Series products are CO E propelled for ozone safety. Precision cleaning agents, flux removers, bulk solvents, circuit refrig- erants, precision dusters, non-residual wipers, premoistened pads/swabs, antistatic compounds, conformal coat- ings, lubricants, adhesives, desolder- ing braids and soldering products. Complete with technical specifications and application guide. Chemtronics Inc. 8125 Cobb Centre Drive Kennesaw, GA 30144 1-800-645-5244 in GA 404-424-4888 CIRCLE 54 ON FREE INFORMATION CARD EARN YOUR B.S.E.E. 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Valley Stream, NY 11580 CIRCLE 192 ON FREE INFORMATION CARD ^& v. *** CIRCLE 108 ON FREE INFORMATION CARD DRAWING BOARD Every test bench needs a good power-supply — here's a rugged 5-volt, 5-amp one you can build yourself. ROBERT GROSSBLATT Over the years, I've made a lot of noise about what you need to do to work on the bench. Just because I haven't talked about it in a while doesn't mean that my opinion has changed — it's just that other things have come up that are more interesting. I don't like writ- ing the same thing over and over any more than you like reading the same thing over and over. I spent a lot of time last month talking about how you have to be sys- tematic when you're working on a de- sign if you want to be able to produce something that works. Not every- body with an understanding of scien- tific facts has an understanding of scientific method, and all the under- standing in the world isn't going to be much good if you don't work in a logical manner. But we've already been through that together. Now we all know that working your way through an original circuit design is a complex business. Even at the best of times, the hassles that pop up can be unexpected, mysterious, and apparently unrelated to the job at hand. While a healthy dose of scien- tific method can direct you to the source of the problem, even some- one who's logical to the point of being obsessive needs a certain amount of hardware to work things out. As you probably realized, I'm talk- ing about test equipment- If you've got a bank book to finance your work bench, you probably already have a good supply of test equipment. How- ever, if you're like most of the people I know, the shelf above your bench, while not absolutely bare, is missing some useful stuff. Test equipment can be divided into two groups — things that should be purchased and things that you can make. Deciding which items to put in which category depends on the kind of work you're doing, the size of your bank account, and your frame of mind. If you like to experiment with multi-zero frequencies or voltages. both safety and sanity should point you toward store-bought equipment. For most of us, however, home-made test equipment can be a reasonable alternative. Over the next several months, we're going to go through the design of some basic equipment for your bench. It won't be the world's most sophisticated stuff but, then again, you're not always designing the world's most sophisticated circuitry. Before we get into designing some hardware, let's spend a minute or so on practicalities. The most common piece of test equipment has got to be a multimeter. There's no reason why you can't build one of your own. but this is a good example of a waste of time, since a good meter can be bought quite inexpensively If you're willing to look at used equipment, the same amount of money will undoubt- edly get you a meter that, a Few years before, was the best one you could buy. Just as some stuff is so cheap that it pays to buy, some test equipment is so complex it pays to buy as well. I'm talking primarily about an os- cilloscope. There are ways to convert TV's and monitors to work as os- cilloscopes but every one I've seen is more than a one evening's project and the result is, quite frankly, not worth the time spent on the conversion. If you're interested in building some- thing like that, some companies have kits for scopes that end up being good pieces of test equipment. Before you go out and spend money, however, be aware that all those kits are complex, costly, and if you screw up it takes a lot of time to get them working properly. When we get further into this, we'll take a look at alternatives to commercial os- cilloscopes but there's no way the stuff we'll design will be the func- tional equivalent of a commercial scope in either bandwidth or fea- tures. But you'll see what I mean when we get there. One of the most basic things to have on your test bench is a good power-supply and that's one of the things you can easily make on your own in just one evening. Since the job of a power-supply is to provide clean power, many good designs can be built around easily available parts. A few years ago, 1 went through the design of a variable 5-amp power- supply based on the standard 78-se- ries of voltage regulators. If you're interested in all the details, you'll find them in the May to August, 1983 is- sues of Radio Electronics DC VOLTAOE. FIG. 1— IN THIS 5-VOLT, 5-AMP POWER-SUPPLY, IC1 is a 7805 voltage regulator; CI, C3 and C4 filter voltage spikes; D1 is a "swamp diode;" Q1 is a pass transistor; and 02 is a limit transistor. > o ■j. ii R-E Engineering Admart Rates: Ads are IWkM". One insertion S995 each. Six insertions $950 each. Twelve insertions $925 each. Closing date same as regular rate card. Send order with remittance to Engineering Admart, Radio-Electronics Magazine, 500-B Si-County Blvd., Famiingdale, NY 11735. Direct telephone inquiries to Arline Fishman. area code-1-516-293-3000. FAX 1-516-293-3115. Only 180% Engineering ads ate accepted for this Admart. FCC LICENSE PREPARATION The FCC has revised and updated the commercial license exam. The NEW EXAM covers updated marine and aviation rules and regulations, transistor and digital circuitry. THE GENERAL RADIOTELEPHONE OPERATOR LICENSE - STUDY GUIDE contains vital information. VIDEO SEMINAR KITS ARE NOW AVAILABLE. 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CIRCLE 190 ON FREE INFORMATION CARD in o z o (X o < en The final design is shown in Fig. 1. While there's not enough room here to go into a complete analysis of how the circuit was designed, we'll explain how it works. Even though this is a home-built supply, it can supply just as much power as a lot of the com- mercial ones and should be treated with just as much respect. Five volts may not sound like a lot to you, but at five amps, it can vaporize metal and do all sorts of nasty things. If you want to get all the power that this supply is designed to deliver, you'll need an input transformer that can put out at least 25 volts and 8 amps. If you can't find one and are forced to settle for something with less muscle, just remember that your output power will be reduced. An 18- volt transformer is going to give you a maximum supply output voltage of about 15 volts. Your choice of transformer will de- termine how hefty a part you need for the full-wave bridge rectifier, BR1. Make sure it can handle the voltage from the transformer and can stand a current draw of at least 5 amps. Multi- ply your voltage and current numbers by 2 and add fifty percent to give yourself a good safety margin for the wattage of the rectifier. If you've used any of the 78XX reg- ulators before, you'll recognize the basic regulator circuit in the sche- matic. Capacitors C1 . C3, and C4 are used as filters to suppress voltage surges that appear on either the input or output of the supply. Every reg- ulator design has parts to take care of AC ripple and transient voltage spikes. The shortcoming of the basic reg- ulator design is that whenever you add capacitors to keep the output clean, you're also adding potential problems. One of the most common screwups that has to be handled by a bench power-supply is a short circuit. Since the work area is always littered with clip leads and small pieces of wire (even the ones used on the breadboard), there's always the pos- sibility for shorts to occur. Output shorts are no problem since the 7805 will rapidly reach its thermal overload point and shut itself down. It may get a bit hot but that's about all. An input short, however, can be a real disaster. When the input of the 7805 is shorted, the output of the regulator will be at a higher volt- age than the input. Capacitor C4 will discharge into the regulator's output and current will flow into the output of the regulator. That means the chip's internal pass transistor will be re- verse-biased and the only thing you'll be able to do with the 7805 is gold plate it and wear it on your ear. The problem of an input short is handled by Dt — usually known as the "swamp diode." When everything is working properly, the voltage at the regulator's input will be greater than the voltage at its output and D1 will be reverse biased. If the 7805 input is shorted to ground, however, the out- put voltage will be higher than the input and D1 will be forward biased. Most of C4's current will be shunted by Dl and passed to ground through the input short, which will save the 7805 and whatever happens to be powered by the supply. When the regulator's current sup- ply limit is reached (about one amp for a heatsinked 7805), Q] will work as a pass transistor and take up the extra current demands of the circuit being driven by the supply. Transistor 01 is set up as a simple switch and is controlled by R5. All the supply cur- rent passes through R5 and, as it increases, it will reach a point where the voltage across it is high enough to turn on Q1 and the transistor will start supplying current at the output of the power-supply. No matter how hefty a transistor you pick for Q] (the MJ2955 can easily handle 10 amps) the potential is there for the same sort of disaster we saw earlier at the output of the 7805. We can guard against that by putting 02 in the circuit. Transistor Q2 is also used as a 78 switch but its job is to shut everything down if the current draw exceeds a preset limit, hence the name "limit transistor." The turn -on point of Q2 is controlled by R3-R4 in exactly the same way R5 controlled the turn-on point of Q1. When Q2 turns on, how- ever, it will lower the voltage across R5, turn off Q1. and shut down the supply. The supply's voltage can be varied because of op-amp IC2. The op-amp is set up as a non-inverting buffer to isolate the output stage of the circuit from the regulator's ground leg. When you use R2 to change the volt- age at the op-amp's input, you'll also change the voltage at the ground leg of the 7805 and force the supply to vary its output voltage as well. You won't be able to get volts out of the supply but since there aren't a lot of circuits that run on volts, that shouldn't be much of a drawback. A value of 100 ohms for R1 means you'll have a minimum voltage of about 5.1 5 volts for the supply. There's a good deal of math in- volved in calculating the resistor val- ues so don't stray from them unless you're sure you know what you're doing. The values for R3, R4, and R5 are all linked together so just re- member that changing one means changing all of them. The supply can be built with any technique you want. Just remember to sink the 7805 and all the tran- sistors as well. Put everything in a plastic box and be certain that the whole thing is properly wired to- gether and make sure that all wires are properly covered. If you want to do some experimenting with the cur- rent and trip settings, you're going to have to understand the way the val- ues are calculated. It's not difficult since it's really nothing more than an application of Ohm's law. The value for R5 can be figured out in two ways; the easy way and the hard way. Even though there's a dif- ference in the assumptions made for each method, the practical results are just about the same. If you take a good look at the circuit, you'll see that the emitter-base junction of 01, along with R3 and R4, should be con- sidered as you calculate R5 since they sit in the circuit with the emitter- collector junction of Q2. That makes things a bit hairy since the impedance of the transistor is going to change with current flow, voltage, and the other circuit parameters. Speaking practically, however, the effect of Ql's emitter-base junction is minimal com- pared to the voltage drop across R5 so we can safely do things the easy way and ignore 01 ■ With that in mind, we can calculate the value of R5 by a straight applica- tion of Ohm's law. The 7805 can easi- ly handle half an amp but let's play it safe and have 01 turn on when the current flow in the regulator exceeds 250 milliamps. The turn-on voltage for Ql, as it is for any silicon tran- sistor, is 0.65 volts. Since we want it to turn on when the current flow is 250 milliamps, we can get the value for R5 from Ohm's law. R5=E/1 R5 = 0.65 V/0.250 A R5 = 2.6 ohms Since R3 and R4 are in series with R5, the value of 2.6 ohms is therefore the total for all three resistors. In order to find the correct value for R5, we have to work out the value for the parallel combination of R3 and R4. The problem can be simplified by ignoring the emitter-base junction of 02. The practical effect is minimal and the value we get without consid- ering it is, as they say, "close enough for government work." R3/R4 = E/l R3/R4 = 0.65 V/5.0 A R3/R4 = 0.13ohms The final value for R5 is simply R5 = R TOTAL -(R3/R4) R5 = 2.6-0.13 R5 = 2.47 ohms Since a 2.47-ohm resistor isn't ex- actly a common thing, I've used a standard 2-ohm value instead. That changes the circuit trip points a bit but makes building it much easier. You can use several resistors in com- bination to get 2.47 ohms but it's not really worth the trouble. When we get together next time, we'll look at some test equipment to build. We'll start out with some stan- dard digital stuff and see where we can go from there. You'll begin to see that, even though some test equip- ment is too complex to build, there are other items that can be built quite easily You'll not only save money by building certain items, but you'll also gain a complete understanding of how the device works, and have the fun of building it yourself. R-E DMM Test Leads That Will Last. At Last. On the bench or out in the field you're left to your own devices. That's why Pomona has developed 12 different DMM Test Lead Kits. Yon can reliably attach different probes or clips to the same lead because Pomona's "Pop Jack" coupler holds tight, just like a Chinese finger puzzle until you "unlock" it. Silicone insulated wire feels great, won't be burned by the bump of a soldering iron, and stays flexible in cold temperatures. Choice Quality, Choice Selection. These, and a host of other features like field repairability, low-cost slide-on tips, extendable and replaceable probe tips, and a rugged pouch or case to fit in pocket or toolbox, make them the best choice. Someone's finally making test leads that will last. See your nearest Authorized Pomona Distributor or contact POMONA ELECTRONICS 1500 E. Ninth St., P.O. Box 2767 Pomona, CA 91769 {714)623-3463 FAX (714) 629-3317 FREE 1990 CATALOG! Thousands of test accessories and solutions in 138 pages. Call or write for your FREE copy today! ITT Pomona I AN ITT EMC WORLDWIDE COMPANY X -J Discover our strengths. 2 CIRCLE 101 ON FREE INFORMATION CARD 79 O z o DC I LU _l LU o Q < 13 o I S3 COMPUTER CONNECTIONS Making connections. JEFF HDLTZMAN Eventually, even small offices like mine have to face up to the Fact that a bunch of stand- alone PC's is not as powerful as a bunch of networked PC's. But net- works are notorious for being expen- sive, difficult to administer, and time- consuming. In fact, cost is not a major problem; there are numerous low- cost packages designed for network- ing a small office. Initial installation of most low-cost packages is fairly sim- ple, but depending on the complexity of your setup, administrative require- ments increase rapidly, as does the requisite amount of time. During the past few years, I've in- stalled and tried to work with several low-cost LAN solutions, including DeskLink, LANLink, PrinterLAN, ReadyNet, and most recently, LAN- tastic. In each of the first four cases, a brief trial period was enough to con- vince me that networking would have to wait. LANtastic, however, looks like it's going to stay — at least in my system, that is. Why bother? One problem I had to solve was a lack of expansion slots. In my main PC I simply don't have enough inter- face slots for modem, fax, video, se- rial/parallel ports, memory, scanner, tape backup, floppy and hard disk drives. Rather than finding a special motherboard with 16 slots, I can use off-the-shelf hardware, simply add an- other PC to the net, and gain several additional slots. So, in a very real sense, a network becomes a kind of bus extender. And doing it that way makes the overall system more relia- ble, because if a machine goes down, the system as a whole remains oper- g ational. If I stuffed everything in just z one PC, and it died, I'd surely be in § deep trouble. £> Another problem is printer sharing. 9 Laser printers still aren't cheap ^ enough to dedicate one per machine 5 unless, that is, if you have a tremen- 1Mbi IMlt 80 ns 5.50 m - kfcc 41256 256K>Lt 100 ns 2.40 P I Su 41256 256 Kk I 120 ns 2.20 m l 442S6 Z56Kx O I 85 DIGITAL VIDEO STABILIZER ELIMINATES ALL VIDEO COPY PROTECTIONS While watching rental movlw, you will nolic* an- noying periodic color darkening, color shift, un- wanted lino»< flashing or jagged edges. This is caused by the copy protec- tion jamming signals em- bedded in the video tape, such as Macrovision copy protection. Digital Video Stabilizer; RXII completely eliminates all copy protec- tions and Jamming signals and brings you crystal clear pictures, FEATURES: • Easy to use and a snap to install • Slate- of -t he-art in- tegrated circuit technol- • 100% automatic - no need for any troublesome adjusl- ments • Gompalible to all types of VCRs and TVs •The best and most excit- ing video Stabilizer in the market • Light weight (8 ounce s) and Compact (1x3,5x5) • Beautiful deluxe gift box • Uses a standard 5 Volt battery which will last 1- 2 years. WARNING : SCO Electronics and RXII dealers do not encourage people to use the Digital Video Stabilizer to duplicate rental movies or copyrighted video tapes. RXII is in- tended to stabi- lize and restore crystal clear picture quality for private home use only. ( Dealars Welcome ) To Order: S49.95 «a * $4 foi fast ups shipping 1-800-445-9285 or 516-568-9850 Visa, M/C, COD M-F: 9-6 (batlery not Included) SCO ELECTRONICS INC. Dept- fiiij 561 W. Maffick Re. 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Also transformers, capacitors and parts for tube equipment. Send $2.00 for 28 page wholesale catalog. ANTIQUE ELECTRONIC SUPPLY 6221 S. Maple St. »Tempe. AZ S5238 • 602/820-541 1 WIRELESS CABLE - IFTS - MMDS - Am! [but TV Ultra High Bain 50dh(OOh 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 'Wo one beats the King's prices!" DESCRAMBLERS Try the 'names, bulletin board system (RE-BBS) 516-293-2283 The more you use it the mora useful It becomes. We support 300 and 1200 baud operation. Parameters: SHI (8 data bits, no parity, 1 stop bit) or 7E1 (7 data bits, even parity, 1 stop bit). Add yourtell to our user Dies to Increase your access. Communicate with other R-E readers. Leave your comments on R-E with the SYSOP, RE-BBS 516-293-2283 L 30 CH PARABOLIC DISK SWUM S173.S0 30 CH ROD ANTENNA SYSTEM S193.90 30 CH CRYSTAL CONTROLLED STS1EMS291 9S SIJ.H MICKOWAVE INTL. INC. SEND $1.00 FOR ' ', "! D) ■■ I v. :: CATALOG OH THESE PHOENIX. A2. 85187 AND OTHER I I'.f (5011 I30-OH0 VIOEO PRODUCTS HI! AN lllir DISCOUNTS ELECTRONIC supermarket great buys! surplus prices. IC's. DC motors, vacuum pump, transfor- mers, PS, steppi no-motors, builders, engineers, ex- perimenters, LSASE, FERTIK'S, 5400 Ella, Phila., PA 19120. CABLE TV converters & descramblers for Jer- rold and Scientific Atlanta. Low prices, one year warranty. We ship COD. SAY STATE ELEC- TRONICS, PO Box 103, Boston, MA 0218a. 1 (BOO) 359-9806, ESTATE SALE. Collection of Radio-Electronics magazines going back to 1956 Too valuable to throw away. Write with best firm offer to: MRS. ALICE I. OLSON, 29465 Vista Plaza Drive, Laguna Niguel. CA 92677, COMMUNICATIONS SECURITY ASSOCIATION — Electronic surveillance, countersurveillance, communications security topics — membership in- formation — POB 7069, Gaithersburg, MD 20898. BBS (202) 364-1304, ROBOTICS software, PC/MSDOS. Explore com- puter vision, sonar sensing. Free brochure, ROBOTS ETC, Box 122, Tempe, AZ 85280. TEST equipment pre-owned now at affordable prices. Signal generators from $50.00, os- cilloscopes from $50.00, other equipment, including manuals available. Send S2.00 U.S. for catalog, refunded on 1st order. J.B. ELECTRONICS, 3446 Dempster, Skokie, IL 60076. (708) 982-1973. CAR stereos, equalizers, amplifiers, speakers, woofers, tweeters, speaker box supplies, alarms, DJ mixers, more. Large catalog $1.00. ELEC- TRISONIC-K1, 8400 Alameda, El Paso, TX 79907. CABLE TV, Tocorn 5503 $199.00, Oak RTC-56 $150.00, Jerrold 400DIC $125.00, Hamlin 6600 $125.00, all with remote, Tri-Bi or SA-3-B $79.00, C.O.D. orders welcome. Call S.A.C., info (702) 647-3799. Orders 1 (800) 622-3799. LOCKPICKS, car opening tools, surveillance equipment, protection devices, books, more! Cata- log: $3.00. MICHAEL FREEMAN, Box 179, Hunt- ington, NY 11743. CABLE converters, all major brands. 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Hamlin Combos $44, Oak M358 $60 (mln. 5), etc. WEST COAST ELECTRONICS For Information: 818-709-1758 Catalogs & Orders: 800-628-9656 TUBES Sylvania 6LQ6, 6L6GC, 20LF6 etc Huge discounts. ARLEN SUPPLY, 7409 West Chester Pike, Upper Darby. PA 19082 1 (800) 458-1301 CABLE boxes: wholesale prices to all, Oak RTC-56 with remote $150.00, Zenith 2-Tac $225.00, Tocom 5503 with remote $199.00, MLD-1200 Hamlin $45.00, Jerrold-400 $125.00, Tri-Bi super fast $79.00, SA 3-B $79.00, Oak M358 S39.00, all other brands in stock, C.O.D, ok, same day shipping^ quantity prices available call, MOUNT HOOD ELECTRONICS, (503) 253-0459. PLANS AND KITS CATALOG: hobby broadcasting HAM CB: Cable TV, transmitters, amplifiers, surveillance devices, computers, more! PAN AXIS, Box 130-F3. Para- dise. CA 95967. REMOT E CONTROL KEYCHAIN ^ er~^2^ Complete wmint-trangmitter and +S.vdc RF receiver^-: Fully assembled including plans to build your own auto al&rmOy Quantity discounts., available ■ ry/t r\c Check, Visa or M7C X^.yD ;. Add $ 3 shipping VISITECT INC. BOX 5442, SO. SAN FRAN./CA, 940BO ■'■■'■ : (415) 872-0128, Fa* (415) 872-2635 INVESTIGATORS, experimenters — Quality new plans Micro and restricted devices. Free catalog. Self addressed stamped envelope required K EL- LEY SECURITY INC., Suite 90, 2531 Sawlelle Blvd., Los Angeles, CA 90064. 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- LASER lighting entertainment systems and ac- cessories. Create 3-d i mens ional laser light shows with these professional secrets! Electronic and me- chanical designs for all budgets! $20.00. MILLEN- NIUM, 229 McAlee, Thousand Oaks, CA 91360. 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JERROLD OAK-SCIENTIFIC ATLANTA-HAMHN ZENITH MANY MORE CALL TODAYI V 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 I 5114 Balcones Wood Dr.#307 Dept.298 ^^^Austir^TX^8759^^ OA2ER II personal protection device! Plans $8.00, Lasers! Transmitters! Detectors! More! Kits or as- sembled! Catalog S2.00. QUANTUM RESEARCH, 16645-113 Avenue. Edmonton, Alberta T5M 2X2. DESCRAMBLING. new secret manual. Build your own descramblers for cable and subscription TV. Instructions, schematics for SSAVI, gated sync, sinewave, (HBO, Cinemax, Showtime, UHF, adult) $12.95, $2.00 postage CABLETRONICS, Box 3Q502R, Bethesda, MD 20824. MARK V CLCCTRONKS, INC. Competitive Pricing * Fast Shipping Since 1985 . indicates the level of difficulty in the assembling of our Products. A Beginner TA120MK2 tHS^w TA-360O K y TA-477 TR-355A/B* ORDER IN CALIFORNIA 800-521 -MARK ORDER OUTSIDE CA 800-423-3483 FREE CATALOG & INFORMATION (213)888-8988 FAX (213) 888-6868 . Advanced + Fully Assembled SM-49 'SM-333 ■m ** AMPLIFIERS KIT ASSEMB SM-66S metalcabinet * Free gilt for any purchase before Apn transformer TY-43 MODEL DESCRIPTION TA .28MK.2 Oigilal Voice Memo A A TA-50A / B MuJII-Purpose Melody Generator A TA-50C Murti-Purpose Melody Generaaor a T«-t20MK7 35W Class "A" Mam Power Mono Amp u ta jDO 30W Mudj-PorposeSiflflie Channel Amp a SM-302 60W - &TJW Slereo Power Am phher I wMn Mm input] A A TA-323A SOW X 2 Slereo Pre-miin Amp A TA-377A Hi-Ouilny FET Stereo Pre-Amp. AAA TA.4D0 nrM Solid Slate Mono A-np a TA-477 120WMos1etPowerMonoAmp.AA TA-S0OMK2 i 20W * 120W low Tim Pte-Mam stereo Power Amp a* TA-B02 SOW r SOW DC Stereo Main Powei Amp. A A TA-620A COW y BOW OCL DC Pre-Main Slereo Amp aa TA-10O0A 1 DOW D> naimr. ctass'A' r.'a n Pomf Mono Amp AA T A- 1 500 l OOW X 2 Class "A" DC Stereo Pre-Mam Amp AAA TA-22O0 Fet Super Class ~A r 0C Pre-Amp AAA TA-2400A Eleclronic Ecno 4 AeverlwraSton Amp w TA-25O0 HO. Pre-Amp wrio band graphic equalizer w TA-2800 HI-FET IC Pre .Amp w/3 way lone comrpl a a TA-3000 Slereo Simulator (Fcr Mono TV or Any Mono Source I A A TA- 3600 3MW HQ Hr-Fi Power Wnno Amu A A A S30 00 12 84 13 65 31 SO 2000 31 50 59 95 75 CO 68 00 6392 45 94 40.39 59 69 w?o 47 70 it 10 27 00 SSOO 1720 ia?i 42 10 23 00 7300 42 M 75 00 34 93 35 00 5S72 45 37 90 53 95 51 58 24 9500 63 30 6357 33 50 11000 POWER SUPPLIES KIT ASSEMB. TR-100A 0-1 5V 2A Regulated DC Power Supply * FR -3S5A ■ sv ■ 5A leg j bi ea n C Powe i Supp r» A TR-355S 0-30V 3A Regulated DC Power Suppty A TP.-503 O.50V 3A Regulated DC Power Supply A A S S69 50 15 65 2176 15 65 2175 16 75 23 55 MISCELLANEOUS KIT ASSEMB, WODEt DESCRIPTION TY-23B 3 Channel Dolor Lighl Controller * I S 65 00 IT!) Skied Uudspeakei Proleclor A 1415 70 35 TY-3S FM Wireless MicropAone A .1125 TY-36 AC'OC tbiuU OnHIJI Clock A 1900 2E20 TY-38 Sound ' Tpuch Comrpl Switch A 12.00 TY-4IMKV Infaied Fternglt Control Unit WCasil AAA 2200 35 00 TT-42 Ba' Dm Lenl Meier A A 24 15 33 81 TV-43 3i, Digilii Panel Meter a 2900 33- 00 TY-45 20 Steps Bar I Dal Audio Level Display A A 33 45 46 14 FV-47 Supenpr Electronic Ftoulelle A A 19 46 27 24 SM-222 7 Band HI-FI Graphic Esuallier A A A 23 80 3880 SM-328 4 Channel p-olessional Color ujm ContrcJiei * 145 00- SM-333 AudroMdeo Sutround Sound Processor AAA* 65 00 75 00 SMtBB Ovnami mia Reouciun a ;boo 34 oo SM-B88 Universal Audio,Vktfeo KARAOKE Miwr Pre-Amp * 225 00 lO.OOOul 30 V Capacitor (Suggested ro> lA.JEOO TA-477 IA-IUOA !. 1A-307) 23 00 METAL CABINETS WflH ALUMINUM PANEL MODEL H"xW i D' MATCHING lG-1273 i 12 7' TA-2SO0. TA-377A, tA-2200 LG-16B1 4- 16" 8" TA-323A. TA-377A. TA-2200 IG-1924 4' 19" 11') TA-802. TA-B20A. TA-1500 TA120MK2. TA-800. TAIOOOA LG-t925 6 - 19- 1I<» TA-477 TA-MO TA-1500 TA-1O00A TA-3600 LG-t963 j','19 B 1 1A377A TA-28O0. t A 2200 tA-120MK2 PRICE i 22 as 27 60 32.80 3580 29 25 P0WEH THAHSFOHMERS SM-43 SM48 SM48A SM-49 SM-100 FC-100OA INSTRUMENTS KIT ASSEMB. 3 , Mulli-Functional Led o P M ..w.-AOS plasiic caseiAA A^Hh-PrecisonD.PMAAA 4', Hl-Preeisann PM (w/ABS ptestic case)AAA S'-j Mulli-FunCEional LCD D MP (w.'Mold FunclionlAA 150MCDigt1al Frequency GounlerAAA 1 Gttr Frequency Counter + S34 50 36 00 41 20 35 00 79 00 S4300 48 BO 5200 44.50 90.00 179 00 MODEL 001 002 003 004 005 B06 007 DESCRIPTION 79V < 2 SA a 30V < ? f A 36V«2 3A 40V 1 2 EA 24V » 2 BA 26V 1 2 3A 18V«2 5A 53V > 2 SA MATCHING 1A-900. TA-B07 1A.620A TA-1000A TR-503 1A-323A TA-4O0. TA-300 TA-47? TA-120Mt!2 TR-3S58 TR-355A !A3600 PRICE S27 00 22 00 2900 22 BO 15 0ii 1550 > O X VVi - T.rupplg nnh Btttiunh You Demand. We Supply. You demand a huge selection of high-quality audio, video and computer parts and components, shipped quickly without backorders— support from a staff of knowledgeable sales reps — phone-in technical assistance when you need it— and convenient payment terms. NO PROBLEM... when MCM is YOUR electronic resource. For A FREE, ONE- YEAR SUBSCRIPTION to our "POWERHOUSE" Catalog and unbeatable service. Call TOLL-FREE 1-800-543-4330! KiciS MCM ELECTRONICS BSO CONGRESS PARK OH. CENTERVILLE. OH 45459-4073 A PREMIER Company SOURCE NO. RE-69 > o I (O 91 CIRCLE 87 ON FREE INFORMATION CARD ASK R-E continued frvm page 12 against a standard value. Any dif- ferences produce an error voltage that's used to control the speed of the cassette recorder. That type of circuitry usually uses a small potenti- ometer as a voltage divider to provide the reference voltage to the speed control circuit. Changing the speed of the recorder is simply a matter of adjusting the pot. The hook here is that, while it might be easy to adjust a potentiometer, you can't do that until you first know where it is — and that's where the need for the service manual comes in. If your cassette recorder doesn't use that method to control the speed , you'll have to locate the power leads to the motor and add a bit of circuitry to control the motor voltage. That's not hard to do and only requires, as you suggested, a few components. There are several small circuits you can use to control the speed of a small DC motor and one of them is shown in Fig. 1 . Before you start mod- ifying the cassette recorder however, make sure you understand the cir- cuitry. While it's possible to do with- out the service manual to locate the speed control, it's very risky to start cutting wires and adding components unless you know exactly which wires to cut and which ones to leave alone. BASIC DIFFERENCES 1 recently became the owner of an IBM computer and, after setting it up, I noticed that there are two BASIC programs included with the DOS disk. One is called BASIC and the other is called BAS1CA. Could you explain the difference be- tween them? — G. Benjamin, Fischer, NY There are actually three versions of BASIC but the differences between them are really only of historical inter- est since each succeeding one is a superset of the previous ones. The simplest BASIC was cassette BASIC, which was originally burned in EPROM's Cor their equivalents) on the motherboard. That practice end- ed with the introduction of the AT class machines. If you have a real XT made by IBM, chances are that cas- sette basic is sitting in chips on your motherboard. XT clone machines provided sockets for EPROM's but, since BASIC was protected by an IBM copyright, the sockets were nev- er filled. That was left up to you. The intermediate version of the lan- guage contained commands to use the disk drives and was referred to as Disk BASIC. That's the BASIC file you found on your DOS disk. The most advanced of the three versions is BASICA — the "A" stands for "Advanced." It has all the com- mands available in the other versions as well as other commands related to trig, math, and graphics. I believe that IBM has finally stopped including both BASIC and BASICA on their DOS distribution disks but that was even after the in- troduction of DOS 3.2. Current ver- sions of DOS only include the more advanced BASICA. I hope you don't expect me to give you a reason why IBM kept both ver- sions of the language on their distri- bution disks for so long. Quite frankly, I don't have any idea whatsoever and was hoping that either you or some other reader knew why. R-E I 12" CAST FRAME WOOFER CD o z o rr O Q < rr 92 2-1/2" SANYO TWEETER Paper cone wild gold tone dust cap. 8 oz. magnet. 8 ohm. 1/2" ferro lluid voice coil- Power handling: 50 W RMS. 70W max. Frequency re- sponse: 3K-20KHZ. #RD-271-020 $1 8S $1 75 95c us; i-a-s&i ite-ufl- SUPER HORN TWEETER Original paezo tweeter made by Motorola. SPb.94dB2.83WM Response: 4KHz- 27KHI. Handles ap- proximately 50 watts. #RD-270-010 H $5 M $4 M $3" 1.1 -9 r (1C-7S, |U't« 2" DOME MIDRANGE Textile dome rnidrange made by Philips. 8 ohm. SPL=90dB1VW1M. 30W RMS. 40 W max. Response: 5S0-5KHZ 3RD-280-210 ^1 ! $27 M fiat 15" SUBWOOFER 10" POLY WOOFER Medium duty. SOW RMS. SOW max. 14 oz. magnet. Response: 25-2.5KHZ. ls=28Hz. #RD- 290-096 $18 w $16* TITANIUM COMPOSITE TWEETER Dual voice coil. 40 oz. magnet. 6 ohm imp. 100W RMS. 140W max. Response: 20-1.2KHZ. Resonant frequency: 21Hz SPL=93dB1W/1M. #RD-290-190 $54 H $49 M [VlJ H-up) SUBWOOFER XOVER 20QW RMS crossover designed specifically (or use with dual voice coil sub wcofers- 1 2 dB per octave roll-oft at The advantages of both hard and soft dome technologies 8 ohm. Ferro fluid cooled voice coil SPUSQdB 1W/1M 50W RMS, 70W ma*. 4" round, Poiydax #DTW10GT125 #RD-270-047 i i ,jbi ■■■U . -, .^. . IPJ.'L. "*.1U M^a M,M» A U O I io to 93 CIRCLE 187 ON FREE INFORMATION CARD SAVE MONEY. WrrtflV77 II NEXT MONTH CABLE TV DESCRAMBLERS, CONVERTERS, & ACCESSORIES. Save hundreds of dollars owning instead of renting from the cable company. Easy to order and install. Name brands — Pioneer, Oak, Panasonic, jerrold, Scientific Atlanta and more. We're famous for lowest prices, excellent service and immediate delivery. All products fully warranted. Your satisfaction is 100% guaranteed. o z 5 LU _! LU Q a < 94 CALL FOR FREE FULLY ILLUSTRATED 16-PAGE COLOR CATALOG. (800)234-1006 SCIENTIFIC & ELECTRONIC PRODUCTS USERS AND SCIENTIFIC DEVICES VRL!K 3mwVisFted Laser Diode System Kit 515S.50 LLI51K User Beam-Bounce" Listener Kit S1SS.50 LHU2K VisibleSirmiIaled3ColorLaserK.il S44.50 l C7 40 Walt Burning Cultinrj Laser Flam s:o do FiLIG-4 HI Powered Pulsed Drilling Laser Plans.-., 520.00 LGU40 1 lo ZmwHeNe Vis Rid Laser Gun Assembled 519900 LLS1 Laser Lite Show- 3 Melhmls Plans $20.00 S05K See id Bit Dark Kit 5299.50 EML1K Electromagnetic Coil Gun Kit $69.90 MCP1 HI Velocity Coil Gun Kim $15.00 LEVI Levitating Device Plans .....510.00 EH1 Electronic Hypnotism Techniques Plans..... ..$10.00 HIGH VOLTAGE AND PLASMA 1 SPLAY DEVICES HVMTK 75,000 Voll DC Variable Output Lab Source Kit $149.50 E0G3K Ion Hay Con Kit, project energy without wires $69.50 N1G9K 1?V/i15 VAC Hi Out Keg Ion Generator Kit $34.50 EMA1K Telekinelic Enhancer/Electric Man Assembled $99.50 LG5K Lightning Display Globe KI1 $54.50 ETC1K Wo rids Smallest Testa Coll Kit $49.50 BTC3K 259KV Table lop Tesla Coil Kit $249.50 BTC5 1.5 Million Volts Testa Coil Plans $20.00 JL3 Jacobs Ladder - 3 Models Plans $15.00 GBA1 Anti Gravity Generator Plans $10.00 PFS20 Plasma Fire Saber Assernhled $69.50 DPL20 Dancing Plasma lo Music and Sounds Assembled $79.50 SECURITY AND PROTECTION DEVICES 17M10 100,000 Volt Inlimidalor up to 20' Assembled $129.50 IPG70 Invisible Pain Field Blast Wave Gen Assembled $74.50 PSP4K Pbasor Sonic Blast Wane Pistol Kit $59.50 1 1ST 1 Infinity Xrttlr, listen in Via Phone Assembled $199.50 TAT3G Automatic Tel Recording Device Assembled... $24.50 VWPM7K3rVti.FMAuloTelTransmlllerll.it $49.50 FMV1K 3 Mi FM Vnice Transmiller Kit ..$39.50 K0D1K Homingrtra eking Beeper Transmiller Kit. 549.50 EASY PRDEniNC PROCEDURE TOLL FREE 1900-221-1705 or 24 BFIS ON 1.503-673.473(1 11 FAX IT TO 1-603-572-5106 VISA. MC. CHECK, MO IN US FUNDS. INCLUDE 10% SHIPPING. ORDERS 51 CD. 3D A. LIP ONLY ADD $10. OQ. CATALOG 51. DD OR FREE WITH OB DEB. INFORMATION UNLIMITED P.O. BOX 716, DEPT. R3, AMHERST, NH 03031 Exciting Features, Projects, Reports, & Columns • BUILD AN ULTRASONIC PEST REPELLER Our pocket-sized circuit makes out- door fun bug free • BUILD A REGENERATIVE RADIO An entertaining project that's based on an age-oid design MAKE YOUR OWN CUSTOM CASES It's easy to add eye-appeal to your next project AN "ELECTRONIC" FISHING LURE A fun project for the adventurous angler Po pular Electronics And there is more! PRODUCT REVIEWS— jvc dat Player, Go Video Dual-Deck VCR, Radio Shack Combination Laser Vid- eo Disc/CD Player, and much more, DX LISTENING— Radio fare from "Down Under." COMPUTER BITS— The Swiss Army Knife" of utility programs. THINK TANK — Teaching your old TTL logic gates some new tricks, a phone-line tester, an intrusion alarm, and more, HAM RADIO — Collecting antique ham gear. ANTIQUE RADIO— A theremin "bibliography." pick up lu puiai Liaiimui> at your favorite NEWSSTAND, CONVENIENCE STORE, OR SUPERMARKET. QUALITY PARTS DISCOUNT PRICES FAST SHIPPING m lead-acid (gelt cell).^^^ 2-X 1.635" X 2" high. Batteries are propped with 5" black and red leads terminat- ed with 2 pin connectot. CAT*GC-61 $4.75 each 10 tor $42.50 Nickel-Cad AAA SIZE $1.50 each 1 ,2 volts 1 80 mAh CAT* HCB-AAA AASIZE $2.00 each 1.25 volts 500 mAh CAT* NCB-AA AASIZE $2.20 each WITH SOLDER TABS CAT* NCB-SAA CSI7E $4.25 each 1.2 vorts 1200 mAh CAT* h'CB-C DSIZE $4.50 each l^xotls 1200 mAh CAT* NCB-D HEAVY DUTY "C" YUASA 1800C pt Nickel-cad heavy '§ '.' duty "C" cell *- J 1 .2 volt, 1 800 mah Price reduced on 10 or more. CAT* HDNCB-C 10 tor $42.60/100 tor $375,00 '^ High quality molded ABS Instrument enclosures. Integrated PC board standoffs and two sets of vertical mounting blots for front and rear sub panels. All enclosures are 6" wide X 6 1/4" deep. Choice of three Ms. Includes non-Skid rubber feet and hardware. Available In beige, ivory, black, and blue. Pan* '■ L CATf SIM" CAT*HB-A (7.&0 **cti IDfarSBS.M 2 Sfff CAT* MB B |775 each 10 kx S67 M 3" CATJMIVC *8 CO Bach 10tor*7Q.OO Pkaasfl speedy color RG-11/U VIDEO CABLE 100 ft. or 200 It. rolls of RG 1 1AJ 75 ohm cable terminated to heavy duty F connectors. Includes 75 ohm terminator and F-61 splicer on one end. New cables manu- factured: tor IBM PC networks. IBM PAi 1501908 COM /SCOPE. CAT* BG-1 1-1 100 ft. roll $15.00 CAT* HG-H-2 200 It. roll $27,50 Standard JUMBO DKfused T 1-3/4 size (5 mm) RED CAT* LED-1 10 tor $1.50 • I00for$13.00 GREEN CAT*LED-2 10 lor $2.00 ■ 100 tor $17.00 YELLOW CAT* LED-3 to tor $2.00 -100 lor $17.00 FLASHING LED W/buIrt In Hashing circuit 5 VOX operation. T 1-3/4 (5mm) __^^^ RED $1.00 each CAT#LED-4 10 lor $9.50 GREEH $1.00 each CAT* LED-4G 10 far $9.50 YELLOW $1.00 each CAT* LEO-4V 10 lor $9.50 LED HOLDER Two piece holder, ** ® CAT#HLE0 tOforSSc OWE MINUTE TIMER OPTO SENSORS This while box with a blue button will driva you crazy. Box measures 3 1/4" square X 2" high. Whan Lhe button la pressed 4 LEDs light and a beeper pulses. Every 1 5 seconds one led goes out and the speed of lha beeping Increases. At the end of 60 sec- onds lhe unit gives otf a long beep followed by a low squelch, all LEDs shut oil and the unit stops. Unit requires a 9 volt transistor battery (not included) to operate. CAT#TMFM 32.25 each - 10 lor 320,00 Experimenters Delight ATARI 5200 Vidio Game Alan video game controllers returned to the dealer because Of various defects. None of them wo* k properl v, but they have bis- of great parts. A RF video modulatory ht 16K dynamic RAM& in sockets, microprocessors and D-A converters In sockets, two voltage regulators on a heavy-duty healsink and lots ol other ICs. tetpadfors. resistors, connectors and other corrponent. Does not include the power transformer or controls (joysticks). CAT* A-5200 37.60 each * 2 for 313,50 SOLDAS-tS For Pjrt* Only, ^tMft Honeywell r^Vp, * HOA 0S66.N55 JO U-shaped opto |! (1 sensor. 1/B' gap.4pc leads. CAT*0SU-8 76* each TRVWOPB-SIB U-shaped opto switch. 0,2" gap between sensor and emitter. CAT*OSU-« 754 each TRW* OPS 822SD Roiled ivo scanner module. U-shaped device wSh 4 leads each ■Ida (8 total) 0.09" gap. 0.75' mounting censors. CAT* OS U- 10 76* each TRW* OPB-708 r*V Wedge-shaped / « \\ reflective ppto St^-tt-5 sensor. ' CAT*OSR-5 75c each r^v LED. FLASHER KIT Two L.E.D/s Hash In unison when a 9 vol SP 1 "--"■'- battery la attached. This kit includes a px. board, all the parts and Instructions to make a simple flash- er circuit. A quick and easy project lor anyone wtth basic soldering skills. CAT*LEDKJT f 1.75 per W LE.D. CHASER KIT Build this variable b v speed ted chaser. - pjj fijj^iJjijt 10 led* tlash V.(L, JT\ sequentially at *\ \_^ whatever speed you set them for. Easy to build kit include* pc board, part* and Instructions. Ideal tor special lighting effects, costumes, etc. Oper- ates on 3 to 9 volts. PC board is 5' X 2.25". A great one hour project. CAT*AEC 16.50 each STEPPING MOTOR CONTROLLER KIT Learn about stepping motors while building this simple circuit. Includes cuajit board, stepping motor and all parts except 12 Vdc power supply. CAUSMKIT $1S.00each METRONOME KIT This Eimple device cam be set to click trom 20 to 1 ,000 beats per minute. Easy to build, includes circuit board, all components and Instructions. Oper- ates on a 9 volt battery (not Included). CAT* METRO $3.75 each PHOTO RESISTOR 1 ,000 ohms bright light. S5 16K ohms dark. 1 I 1 0.1 82" dla. X .06-hlgh, 0.1 8" king leads. CAT*PRE-7 2 lor It. 00 100 lor $45.00 • 1 000 lor $400.00 ORDER TOLL FREE 1-800-826-5432 FAX (81 8) 781 -2653 • INFORMATION (81 8) 904-0524 Call Or Writ© For OUT Minimum Order $10.00 • All Orders Can Be Charged To Visa, Mastercard Or Discovercard • California, Add Sales Tax • Shipping And Handling $3.50 Ff&& 60 Page Catalog For the 48 Continental United States - All Others Including Alaska, Hawaii, Outside the U.S. A. send $2,00 P.R. And Canada Must Pay Full Shipping • Quantities Limited • No C.O.D. • postage for a catalog. Prices Subject to change without notice. 5?i»»* MAIL ORDERS TO: ALL ELECTRONICS CORP • P.O. BOX 567 • VAN NUYS, CA 91408 CIRCLE 107 ON FREE INFORMATION CARD Freedom of Choice GoldStar 20MHz Oscilloscope ***SS«^ afl d yto ,\oVJP e Global Specialties Protoboard® Design Station Features: • 6" rectangular CRT display, internal gratitude 8 scale ■ Phase difference measurements between two forms under two methods x-y scope and Dual Trace ■ Two different scale probes: xl and x10 ■ Bandwidth from DC to 20MHz ■ Includes: Two 40MHz probes, two fuses, power cord, operation manual. schematics and block and wiring diagram • High sensitivity: 1 mV/div • Two-year manufacturer's warranty Features; ■ Ideal for analog, digital and microprocessor circuits • Triple DC regulated power supplies. +5V, +15V, -15V ■ 8 logic probe circuits ■ Digital pulser ■ Function generator with sine, square, and triangle waveforms ■ Includes power supply, instrumentation and breadboarding GS7020 $499.95 PB503 $299.95 Jameco Logic Pulser Jameco Logic Probe • Comestible wilh TTL, DTL. RTL HTL HNIL. ii*05 ana CMOS ICs, • IMil Sync input impedance - Pulser mode oulpuE current: lOrnA ■ Square wave current oulput; 5mA ■ Audible [one LP540. $16.95 PROTOTYPING PRODUCTS Jameco Solder less Breadboards Ho. Dim. L- I VT ConucL Binding Poinli Polls Price JE21 3 25 1 2.125 JE23 65 12.125 JE24 65*3125 JE25 I5i42i JE26 6.875 1 5.75 JE27 7 25 « 7.5 400 330 1.360 1,660 2,390 3,220 M.95 $6.95 2 Jt2.95 3 SI 7.95 4 S22.95 < S32.95 * Max Frequency BDMHz - Minimum detectable Pulse 10ns • 120Kti input impedance ■ Max supply voltage. :25V • TTL threshold: [Lo).0.BV :0.1V (Hi) .2.3v 10.2V ■ CMOS threshold: (Lo) 30% VCC M0% (Hi) 70%VCC :10% MS104 ....$24.95 Metex Digital Multimeters General Specs: ■ Handheld, high accuracy * AC/DC vallage. AC/DC currenl, resistance, diodes, continuity, transislor hFE ■ Manual ranging wr overload protection M3650 & M46E0 only: - Also measure frequency and capacitance M4650 only: - Data hold switch - 4.5 digil M 36 1 3 5 Bgit Mulr.irr-.eler .$59.95 M3650 3.5 D^it MuKmeter ^'Frequency & Capaoans S74.95 M4650 i .6 Dvjit ^Frequency, Capacitance ax) Data Mold Switch $99.95 A.R.T. EPROM Programmer • Programs all current EPROMs in the 2716 lo 27512 range plus the X2864 EEPROM •RS232 port ■ Software included EPP $199.95 UVP EPROM Eraser r" • Erases all EP ROM's • Erases 1 chip in 15 minutes and 8 chips in 21 min ■UV intensity: 6800 UW/CM 2 DE4 $79.95 EPROMs - for your programming needs Part Mo. Price Handheld Multimeter J AMECO 24 Hour Order Hotline (415)592-8097 FAX: (415) 592-2503 (415)595-2664 • Partial - 3.5 digit LCD with automatic potanty indication ■ AC/DC voltage measurement up lo 500 volts - AcvDC current measurement up to 200mA - Resistance measurement up 10 20MQ - Con- tmuity checker wiih audible tone ■ Diode and logic tester - Auto/manual range and data hold lunclions ■ All range protection and (unction in- dications TMS2516 TMS2532 TMS2532-35 TMS2532A TMS2564 TMS2716 1702A 2708 2716 2716-1 27C16 2732 2732A-20 2732A-25 2732A-45 27C32 $4.95 6.95 7.49 7.95 5.95 5.95 4.89 6.95 3.49 3.95 4,25 4.95 3.95 3.75 3.49 3.95 Part Mo. Price 2764-20 2764-25 2764-45 2764A-20 2764A-25 27C64-15 27C64-25 271280TP 27128-20 27128-25 27128A-15 27128A-20 27128A-25 27C128-15 27C1 28-25 272560TP $4.95 4.75 4.49 4.25 3.95 4.49 3.49 4.95 6.95 6.25 6.95 5.95 4.95 5.95 5.75 4.95 Part No. Price 27256-15 $5.95 27256-20 5.75 27256-25 5.25 27C256-15 6.95 27C256-20 4.95 27C256-25 4.49 2751 20TP 5.95 27512-20 7.95 27512-25 6.95 27C512-15 8.95 27C512-20 6.95 27C512-25 6,49 27C010-15 14.95 27C010-20 13.95 68764 14.95 68766-35 12.95 Soldering and Desoldering Stations 60 Watt Analog Display Soldering Station • Electronic temperature control from 200" to 878°F • Cartridge heat- ing element tor 3 longer life 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 96 DMM905 $49.95 XY999 $299.95 Listing • Over 4000 Electronic and Computer Components in Stock! CIRCLE 114 ON FREE INFORMATION CARD 24 Hours a Day. ^^nonei* 8 offlS*555 at\d EW Assemble Your own Computer Kit! Jameco 16MHz 80386SX Desktop Computer Kit ■ Building your own computer provides yoj with a better understanding of components and their functions • In-deplh assembly instructions included • Have your new computer assembled and running in an evening, 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) • 101-key enhanced keyboard ■ Multi I/O Card • Toshiba 1 ,44MB, 3.5" DSHD floppy disk drive ■ Baby sized desktop case ■ 200 Watt power supply ■ DR DOS 5.0 by Digital Research and Diagsoft's QAPIus diagnostic software %^3 .95 Hard Drives Conner (16-bit IDE) CP3044 40M6 3 5' Low Praliie $469.95 CP31 84 80MB IS'HH S699.95 CP3104torjMB3.5'HH„ ..$799.95 ADP20 Hosl Adapter., J AMECO 24 Hour Order Hotline (41 5) 592-8097 FAX: (415) 592-2503 {415)595-2664 1355 Shoreway Road Belmont, CA 94002 ..$29.95 Relisys 14" VGA Color Monitor - Max resolution: 720 x 480 •Bandwidlh:3uMHi ■Input: D815-pin (analog) RE9513 $449.95 Jameco 16-bit VGA Card ■ Supports VGA, EGA, CGA. MDA and Hercules modes • Comes wiiti 256KB video RAW upgradable to 5T2KB (eight 41464-80) ■ Capable of 640 x 480 with 255 colors, 800 x 60O with 16 colors VG2000 $149.95 Integrated Circuits Part No. 1-9 10+ Part No, 1-9 10+ 74LS00 $.25 $.15 74LS1S4 S1.29 $1.19 74LS02 .25 .15 74LS155 .49 ,39 74LS03 .25 .15 74 LSI 56 .49 .39 74LS04 .25 .15 74LS157 .45 .35 74LS05 .28 .18 74LS158 .39 .29 74LS06 .59 .49 74LS166 .79 .69 74LS07 .59 .49 74LS169 .99 .89 74LS08 .28 .18 74LS173 .49 .39 74LS10 .25 .15 74LS175 .39 .29 74LS11 .29 .19 74LS181 1.39 1.29 74LS13 .35 .25 74 LSI 39 3.95 3.85 74LS14 .49 .39 74LS190 .59 .49 74LS20 .28 .18 74LS191 .59 .49 74LS21 .29 .19 74LS193 .69 .59 74L.S27 .35 .25 74LS194 .69 .59 74LS30 .28 .18 74LS221 .69 .59 74LS32 .28 .18 74LS240 .59 .49 74LS3B .35 .49 .25 .39 74LS241 74LS323 .59 .49 74LS42 2.49 2.25 74LS47 .85 .75 74LS541 1.09 .99 74LS48 .85 .75 74LS590 5.95 5.75 74LS112 .39 .29 74LS670 .89 .79 74LS122 .55 .45 74LS68B 2.19 1.95 74LS123 .49 .39 81 LS95 .99 .89 74LS125 .49 .39 81 LS97 .99 .89 Miscellaneous Components Potentiometers Values available (insert ohms into space marked "XX"): 50011, IK, 5K, 10K. 20K, 50K, 100K, 1MEG 43PXX 3 /4Wan.15Tum $.99 63PXX V; Watt, 1 Turn $.89 Transistors And Diodes PN2222 $.12 1N4735 $.25 J2N4401 $.15 PN29D7 12 2N3904 ..12 ! 1N4148 07 1N4004 10 ,1N751 15 J2N3055 69 2N2222A 25 I C106B1 49 !lN270 25 Switches JMT1 23 SPDT, On-On (Toggle) $1 .25 206-8 SPST. 16-pin (DIP). $1 .09 MPC121 SPDT, Or>Ott-On (Toggle) $1.19 MS1 02 SPST. Momentary (Push -Button) $.39 D-Sub Connectors and Hoods DB25P Maie.ZS-pin $.65|DB25H Hood $.39 DB25S Female. 25-pin... $.75 1 LEDs XC209RTi.(Red) $.14| XCSS6R T1 a /4, (Red) ...$.12 XC556G T1 3 /4. (Green) ...16! XC556Y T1 V (Yellow) .. .1 6 Low Profile BLP $.11 14LP 12 16LP 13 24LP 19 28LP 22 40LP. 28 IC Sockets Wire Wrap (Gold) Level #2 BWW $.49 14WW 65 16WW 69 24WW 1.0S 28WW 1.29 40WW 1.79 Look to Jameco. • Wide selection of integrated circuits and components • Quality prototype and test equipment - Computer kits and accessories Additional items that Jameco offers: • Tools • Cables ■ Connectors • Data Books - Motherboards • Memory ■ Math Coprocessors • Computer Accessories ■ Power Protection Equipment • Much, much more ! Let us show you woha? we have to offer; call or write lor the latest Jameco catalog! $50.00 Minimum Order Date Sheets ■ 50c each For a FREE 90-Page catalog send $2.00 to cover lirst Class Postage and Handling O1901 Jameca Electronics 3/91 CA Residents Add 6.25%. 6.75% or 7,25% Sales Tax Shipping - Add 5% plus Si. 50 Insurance (May vary according to weigh! and shipping method) Terms: Prices subject to change without notice. Items subject to availability and prior sale. Compute '31 oi termj*aTT3nt,H5 is available upon roquon IBM a * noa1flr«f t*«nniar1, ol Inwndionil Sv4*i«M MaehipM «s Soltiertail Standard & Header Plug Sockets Also Available | ' <^ Please refer to Mail Key 2 when ordering > o I to us ■ Customer Service -Technical Assistance • Credit Department • All Other Inquiries • (41 5) 592-8097 • 7AM -4PM P.S.T. CIRCLE 114 ON FREE INFORMATION CARD 97 3 FORI SPECIAL ON SUB-MINIATURE VOICE FM TRANSMITTERS. KITS CONTAIN PC BOARDS TMX-1 LONG RANGE (3 Ml) ULTRASENSITIVE FM VOICE XMTR with fine tune, range control plus $34.50 •TELX-1 TELEPHONE FM XMTR (3 Ml) auto- matically operates when phone is used. Crystal clear clarity with fine tune and range control. Non detectable S34.50 m ^E^ •ATR-1 AUTOMATIC TELEPHONE RECORDING DEVICE tapes telephone conversation all automatically $1950 ALL THREE OF ABOVE FOR - S69.50 CALL OR SEND VISA, MASTER CHARGE, MONEY ORDER, ETC. TO AMAZING CONCEPTS, BOX 716, AMHERST. NH 03031 (603) 673-4730. g z o rx i— o hi _t LU s o < EC 98 THE ELECTRONIC GOLDMINE < JjATALOGf lecbons of unique dffttric 1 Mfa MfliPki in tfr? HftM 1 QVEfl tfW M Ihw 130 loifFEflttfT ] WW, bargain llHCOJDWO' priced, corporals IJS^^T^OUR in our catfcgl ITJopy TODtfl GHGER COUNTER KIT Pntattf the loiwsl trad Geiger carter kt| attiWt In to *crtj today! Futures arc'trw thin weiied Geigar MutUa- bte and piraekdric speater M emits cite in prorortcn la ine radtfen HeL Defects Safe and Garm-a rayi Will delect radJujFi dials on oid witnss. docks, tHc^grt^ i^ialiQix nijcjca Slat fflL QrikTxIW, Opcfafesbom / if PVJ5*$I m 9/ EBBtry (no( inched} Co-meae win S pans, ftAJjftCjSQ'l board and irGlrijdbrc. C6M7 $39.95 4KV TRIGGER COIL Ub with ny slrate ^ 3 Lii iv.' IrijrjH N1700 S1J25 EA. 100 Is Sso.00 3 INVERTER TRANSFORMER Si^ai * lead iransiormer to use *tn 3SS C B cowl 1SMC to 2sw tor anov hcrescert ruaes irfli scremalic N1703 $2,00 £A I. (WO !■> S1.SOO MIN'ERAUGIIT BLACKUGHT LAMP Pwuce ital tmt ekvA rigin ms* By uVP. Mxei LNG-I 1s- tures fcity potable oceraor. iron la: M batteries {not included). Tfis ham 4 (used and has Be Iras 5000 miSWwaiaa llo-jrescenE n : nffj'j !3 glow briotsly. G812 S29.95 PLASTIC ZIPPER OjOSE BAGS Vit now peer high OjaSrySMillrHC* ripperclKe tops wM »Me blocj, to write oft these re- cteseabte. teas feature I zipper ICCWrro lep lor convenient storage ol small electronic pens. rmtwre. Et itt rave m loiiowing met Sou h mJirjes of 100 only. 2- X 3" G6M 10O.S3.3I) 3"X 4" GSM 100/S3.75 3"X 5" 6665 100/$4.00 4"X 6" G666 100,'SS.SO RARE EARTH SU^R MAGNET Z Marry limes aronrjer pan enrer magnets, tree are ire rota's slrortjrsl cwnmerciilly svaiUhlc magnet; lor Iris see Small sta r/ty atexje 1 ■ ■ 5*r » ii? P on m tz a is tn. try ft remove era; rreonel Iran a em sBe atd jgu'1 rm ltd unless you sue i.yau aril get lot. Great tor ihpusanos ol experiments and arplarlorcs ADVERTISING INDEX sLrtpkus and naw a lew Heches (n«s roi rtctt 1 famine). QggQ $ 1LO 0l MINIMUM ORDER: $10 00 plus S3.00 shipping an) handling We accept MC. Vesj and Money Ordeis SEND ORDERS TO: Trn Electronic GoWmrw PO BSI 5-10B ScOHsdilke. AZ 852E1 PHONE ORDERS rC02> 451-74S4 FAX OflCERS 1E021 Hal-3M5 CIRCLE 185 ON FREE INFORMATION CARD 75 107 84 67 98 109 70 .76 RADIO-ELECTRONICS does not assume any responsibility for errors that may appear in the index below. — Perfect Cable 25 1 1 Pomona Electronics 79 184 Prill! Products International 26 78 Radio Shack 3 181,192 SCO Electronics 76.86 — Star Circuits 26 — Tab Books 5 Tektronix 8 Test Probes 17 Unicorn 93 U.S. Cable 86 Viejo Publications 75 WPT Publications 78 Wholesale Cable 26 Xandi Electronics 23 Free Information Number 108 AMC Sales 180 Ace Communications 14 Ace Products , 23 All Electronics 95 Amazing Concepts . 94,98 Appliance Service 23 Banner Technical Books 16 Beckman 75 C&S Sales 13 CEI 93 — CIE 7,31 — Cable Ready Company 94 54 Chemtronics 76 — Command Productions 67 58 Cook's Institute 76 179 D&D Electronics 28 189 Datak Corporation 27 127 Deco Industries 23 185 Electronic Goldmine 98 — Electronics Book Club 80 121 Fluke Manufacturing CV2 191 General Technics 23 178 Global Specialties : ... 32 — Grantham College 28 86 Healhkit 27 114 Jameco 96.97 1 15 Jensen Tools 23 — King Wholesale 88 87 MCM Electronics 91 53 MD Electronics 90 93 Mark V. Electronics. 89 — McGraw Hill Book Club 38 61 Microprocessors Lnltd 85 117 Mouser 16 177 Multidyne Electronics, Inc 23 — NRI Schools 18 183 Optoelectronics CV3 56 Parts Express 92 176 People's College 25 92 121 187 182 186 190 188 ADVERTISING SALES OFFICE Gernsback Publications, Inc. 500-B Bi-County Blvd. Farmingdale, NY 11735 1(51 6) 293-3000 President: Larry Steckler Vice President: Cathy Steckler For Advertising ONLY 516-293-3000 Fax 1-518-293-3115 Larry Steckler publisher Arline Fishman advertising director Denise Haven advertising assistant Christina Estrada advertising associate Kelly McQuade credit manager Subscriber Customer Service 1- BOO- 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 Lavitan, Eastern Sales Manager Radio-Electronics 259-23 57th Avenue Little Neck. NY 11362 t -71 8-42 8- 6037, 1-516-293-3000 Fax 1-718-225-8594 MIDWEST/Texas/Arkansas/Okla. 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 3000 Jop of the Line Universal Handi-Counter™ . ., -^ $375. CM 2600 Super Sensitive RF Frequency Finder. $325. 2210A Full Range Pocket Size LED. $239. 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MiCads & AC Charger/Adapter Included 1 . Carry Case Antennas and Probes ejrtro, 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 5821 NE 14th Avenue • Ft. Lauderdale, FL 33334 Visa, MC. COD, Cash, M.O. accepted:" Personal Check allow 3 weeks. 5% Shipping, Handling, (Maximum S10) U.S. & Canada. 15% outside continental U.S.A. CIRCLE 183 ON FREE INFORMATION CARD 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 countersurveiilance, you must view this video presentation again and again. Wake up! You may be the victim of stolen words — precious ideas that would have made you very wealthy! Yes, profes- sionals, even rank amateurs, may be lis- tening to your most private con- versations. Wake 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 undetstand Countetsutvei lance Technology. Your very first insight into this highly rewarding field is made possi- ble by a video VHS presentation that you cannot view on broadcast television, sat- ellite, or cable. It presents an informative program prepared by professionals in the field who know rheir 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-tech companies, any competitive industry, or even small businnesses in the same community. The valuable informa- rion they filch may be marketing strat- egies, customer lists, product formulas, manufacturing techniques, even adver- tising plans. 1 n fo rm a t ion' t h i e ves- 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 s^edy installed counrless microphones in the concrete work of the American Embassy building in Moscow. They converted CALL 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 lunchrime encounters. Businessmen need counselling on how to eliminate this in- formation drain. Basic telephone use cou- pled with the user's understanding that someone may be listening or recording viral data and informarion greatly reduces the opportunity for others to purloin meaningful information. RADIO-ELECTRONICS VIDEO OFFER RE 5U0-B Bi-County Blvd. Farmtngdale, NY U735 Please rush my copy of ehcQjuniersurveillance Techniques Vidro VHS Cassette for tA9. 95 plus M.OO for postage and handling. Mo. of Cassettes ordered Amount of payment $ Bill my □ VISA □ MasterCard Card No. Expire Dire / Signature - Name Address Gty , . State . . ZIP . All payments in U.S.A. funds. Canadians add Ss.lK) per VHS cassette. No foreign orders. New York State 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 the 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 what to do when you find it? Bugs of a very small size are easy to build and they can be placed quickly in a matter of seconds, in any object or room. Today you may have used a telephone handset that was bugged. It probably conrained three bugs. One was a phony bug to fool you into believing you found a bug and secured the telephone. The sec- ond bug placates the investigator when he finds the real thing! And the third bug is found only by the professional, who continued to search jusr incase 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, othets require a ttained coun- tersurveillance professional. The professionals viewed on your tele- vision screen reveal information on the latest technological advances like laser- beam snoopers that are installed hun- dreds of feet away from the room they snoop on. The professionals disclose rhar computers yield information too easily. This advertisement was not written by a countersurveillance professional , but by a beginner whose only experience came from viewing the 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 cosring $350-750 and possibly pay hundreds of dollars more if you had to travel to a distant city to attend. Now, for only $49-95 (plus $4.00 P&H) you can view Countersur- veillance Techniques at home and take refresher views often. To obtain your copy, complete the coupon below or call toll free.