Wireless-World-1984
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a` Semiconductor buyer's guide ABC micro Mimicontroller XY plotter update Mobile radio Digital feedback , Australia AS 3.00 Norway Nkr 29.20 -Denmark DKr 34.50 Singapore MS .5.50 LSermany Dm 7.00 Spain Pts 340.00 Greece Dra 220.00 Switzerland SFr 7.00 Holland DFL 8.50 U.S.A. 5 3.75 Italy L 3800, www.americanradiohistory.com bench power supplies THE D RANGE ... Four models: Digital meters D30-2 0-30 volts at 2 amps single 1 mA resolution of current D30 -2T 0-30 volts at 2 amps twin 10 turn voltage control Measure external voltages D30-4 0-30 volts at 4 amps single Output on/off switch CV or Cl operation D100-1 0-100 volts at 1 amp single Send for new colour leaflet now to: FARNELL INSTRUMENTS LIMITED SANDBECK WAY WETHERBY WEST YORKSHIRE LS22 4DH TEL. (0937) 61961 TELEX 557294 OR HARPENDEN TEL. (05827) 66123 CIRCLE 1 FOR FURTHER INFORMATION www.americanradiohistory.com ThcAchcr-ing1e BComputcr The SDS ARCHER - The Z80 based single board computer chosen by professionals and OEM users. FEATURES * High quality double sided plated through PCB * 4 Bytewide memory sockets - upto 64k * Power -fail and watchdog timer circuits * 4 Parallel ports with handshaking * Bus expansion connector * CMOS battery back-up * Counter -timer chip * 2 serial ports * 4 MHz. Z80A Telephone or write for full technical description and price information. OPTIONS * SDS BASIC with autostart and "user program in ROM" facility * SDS DEBUG MONITOR: a powerful 8k byte development aid * On board 120/240 volt mains power supply * Attractive two tone instrument case Morwood Da yt1 Ltd Sherwood House, The Avenue, Farnham Common, Slough SL2 3JX. Tel. 02814-5067 CIRCLE 63 FOR FURTHER DETAILS. FIELD ELECTRIC LTD. 3 SHENLEY ROAD, BOREHAMWOOD, HERTS. %Albumlie Telephone: 01-953 6009 OPEN SIX DAYS A WEEK. 9.00am - 5.00pm THURSDAY 9.00am - 1.00pm ALL POWER SUPPLIES 200-250 VA.C. INPUTS. PRINTED CIRCUIT MOTOR. TYPE G16M4 60V D.C. 2350 SWITCH MODE POWER SUPPLIES. R.P.M... 026.00 3.5 VOLT 10 AMP D.C.. C12.50 EX -EQUIPMENT TESTED G9M4 24G D.C. 3700 DC -AC Inverters ADVANCE 5 VOLT 20 AMP DG. C18.50 CARRIAGE & PACKING ON ABOVE £3.50 5 VOLT 40 AMP D.0 . .. C30.00 5 VOLT 60 AMP D.C. £40.00 Valradio Transvertors CARRIAGE & PACKING ON ABOVE C2.00 12-24V D.C. GEARED MOTOR 3 R.P.M. B10s INS NEW. E8.50 ---_,.:.- Inc c/Pack FARNELL _ - - - - --_ being used all over 5 VOLT 20 AMP D C20.00 6 VOLT 40 AMP DC.. £40.00 jwM+.eiligin the world to provide CARRIAGE & PACKING ON ABOVE C2.00 CASE LAB METER 0-50 MICRO AMP. [9.50 Inc c/ P.WOc.ODEN alternative AC Power for FARNELL FAN COOLED MULTI -RAIL SWITCH MODE Standby purpose, Vital POWER SUPPLY CLARE CL 3001/OPTO-COUPLER 313p EACH 101oI C2.50 SV at 15 AMP SPEC. SHEET/GRAPH AVAILABLE.CARRIAGE & PACKING Services, Mobile, Field, -5V at 5 AMP 300 +12V at 5AMP Marine, Laboratory, - 2V at 5 AMP ORIENTAL MINUATE CENTRIFUGAL BLOWER 115V A.C. Computer, Alarm, £36.00 CARRIAGE 8 PACKING CT. 50. OUTLET 1112 x 11/2 C1150 w Communications, CARRIAGE & PACKING C2.50 - COURANT 0-7V 7AMP D C. C22.50 y ! Medical, Control and STC STEREO HEADPHONES 2004 New Ideal for Industrial applications CARR PACK 2.00 colnmuRKaIKKs. [6.00091rcam/4ga&A2AA,RgCt.DO 1 POWER SUPPLY 110-250 V.A.C. INPUT including Video, TV, SPECIAL OFFER B/W MONITOR TUBES 121n New 5V 1 AMP D.C. Untested .. [500 Callers only 12V 400 M/A D C. 'Camera, Hi-Fi etc. 451/94 TEST PROBES bop PAIR NEW AMPENEOL 5012 INSULATED B.N C. SKT SURFACE £7.50 I CARRIAGE 8 PACKING C1.25 MOUNT ..50p EACH NEW BELLING LEE 1.5 AMP INTERFERENCE SUPRESSOR [1.00 EACH Bln SHUGART 801 DISK DRIVES Es-EOUIp Untested CATHODEN CRYSTAL OSC 20 MHZ [2.330 EACH 175V.A.C.. £17.50canIage&pacXln9250 230V NEONS RED ONLY 5 FOR.. [1.00 230V SUB. MIN. TOGGLE 4c/o 75p EACH 10 FOR C600 SINE/SQUARE WAVE INVERTERS 30 to 1000 watts, RED L.E.D. 2.5M1M 10 FOR.. 01,00 PC. BOARD WITH 4 GATES 2v 2 5A NI -CAD's and other 230V Ic/o KEY SWITCH [1.25 50(or 60) HZ, 115/230V, single phase AC. From 12, componenls [3.00 carnage& paclong 1.50 TEKTRONIK HIGH CURRENT PROBES NEW BOXED Inc 110 SPECIAL OFFER B/W MONITOR TUBES 121n New carnage Mace 24, 50, or 220 Volts DC. Untested. C5.00Callersonly 650 CARRIAGE & PACKING ON ALL ITEMS ALL TRANSFORMERS 250V PRIMARIES. LAMBDA 9-0-9V Standby Power Supplies 65 AMP T/X [25.D0 C. LYONS 250V 10 AMP ISOLATING. [46.00 PROTABLE ISOLATING 115V 4 AMP. I [50.00 (60, 120, 200, 500 or 1000VA) WODEN II 80 AMP C35.00 WODEN 7,6V 120 AMP [40.00 WODEN 27V 30 AMP. C25.00 WODEN 60-0. 60V 60 AMP ISOLATING 0115.00 Power GOODYEAR 115V 50 AMP ISOLATING C115.0U Uninterruptible RING FOR Supplies CARRIAGE & PACKING (60,120, 200 or 500VA) INST COOLING FANS 230V 4'l,ln x x t'/,In . C5.00 115V 4'/,In x 44/,m'/IR xl'/in. C4.75 TESTED GUARANTEED AS NEW VALRADIO POWER LIMITED 115V 4'/.in x 4'/, x lym NEW BOXED. [5.50 115V 61n PAPST NEW BOXED C6.00 230V 64n ETRI/PAPST AS NEW 07.00 AK INTERNATIONAL BUILDING, LAWRENCE ESTATE, GLOBE INST. 12/12V D.C. BLOWER MOTOR NEW C6.50 ROTRON 4,n 115V SKIPPER FAN NEW BOXED [5.50 GREEN LANE, HOUNSLOW, MIDDXTW46DU, CARRIAGE 8 PACKING C1 45 ENGLAND. Tel: 01-570 5622 WE ALSO STOCK AT DISCOUNT PRICES KEYBOARDS, MONITORS. PRINTERS. DISK DRIVES, OTHER TYPES P S.D. TEST TACKLING POWER SUPPLY PROBLEMS SINCE 1937 OF EQUIP., FAN'S, MOTORS F H.P., GEARBOXES ANY ENQUIRIES WELCOME. ALL PRICES INCLUDE V.A.T. UNLESS STATED. CIRCLE 31 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD DECEMBER 1984 1 www.americanradiohistory.com Wireless°uüörld over 70 years in independent electronics publishing December 1984 Volume 90 number 1586 FEATURES 17 37 56 Music keys for the BBC HDTV or EDTV? Semiconductor microcomputer by Tom Ivall suppliers by R.M. Adelson IBC 84 exposed some Who deals in the Software for the investigations into components you need? polyphonic keyboard methods of obtaining And which companies will interface described higher -definition accept private orders?. earlier. television pictures. 69 21 43 Mobile radio systems Multiplexing Hand-held and techniques liquid -crystal displays multimeters by N.S. Cawthorne by T. Segaran Price and performance Report from the York IEE A short description of the data. conference. `black art' of led driving. 23 46 74 More on the XY plotter Speed of light Multi -standard modem by P.N.C. Hill by Roy Hodges Further information on An attempt to explain its by Richard Lambley construction, and constancy, even when the Modifications for line -drop software. light source is in relative problems, and BBC computer connections. motion. 78 31 51 Digital derivative Mimi -controller feedback at I.f. Intelligent eprom Nicholls by J. Rush by Peter programmer A dedicated controller, Hybrid digital -analogue using the 6502, frees a by John Adams rate -information microcomputer for other Computer control software extraction is more duties. and construction. effective than a RC circuit. REGULARS 6 64 82 Comment and News Letters New Products Comal versus Basic: Energy transfer: Flat-bed plotter: BBC engineering designs: relativity: personal logic analyser: Acorn business computer: Baird: multi -tasking Forth: Voicemail. d.c. supplies. picoammeter. 25 71 Communications Circuit ideas Optical power: One led shows six modes: microwave landing: combination lock: 405 -line tv: audio differential line IARU locator: costly h.f. transformer uses op -amps. www.americanradiohistory.com CONTRoi Front cover is a Editor olelrs Richard Newport PHILIP DARRINGTON design, illustrating 01-6613128 cilities Minicontrollerim1C0ntr°llerand this month's survey of m Deputy Editor Given Beambly-languaedel $Révlopiugaprob semiconductor GEOFFREY SHORTER, B.Sc. afBCoo controlleruompúpermwcenttSae takes°ver availability. ldiuuconller 01-6618639 economicalbca ti2s m,{ such Technical Editor Mee'. NEXT MONTH aF ,.N MARTIN ECCLES Single -board computers 01-6618638 nee Ñ mx of dNYn{ ^ mwe are the subject our latest BP,N market scan, in which Projects Editor one d mann, Martin Eccles gives a brief RICHARD LAMBLEY mdu,inals aaxm v¡A 1íEJ udl ,M.t outline of what they are 01-6613039 Núkn.2á;kº *Ole* and their applications. A Tal,11 SIANDMID - table of specifications for News Editor currently available units is ,Muestandard included. DAVID SCOBIE by gichaid 01-6618632 l,ambley In°dern John Linsley Hood and 1° Odificauons Drawing Office Manager Connections m.,.., presents his views on fully ROGER GOODMAN Pe..IldkcmUmnairo symmetrical audio Mt,ÿyBpdNAºp ¡heta dun '^aiem.'BIN amplifiers, with practical 01-6618690 aadet pa°nµnºa`dZ!iuF+ todNmíNn s.a VBSC1Mv^hna°4 °ºtWwt d.. the aro.. 815 circuits for a moving -coil head amplifier and a gain Technical Illustrator iBmeddreuVPº block. BETTY PALMER rt/rdºa° IaPoc aMn1Fe - `' - t-, anymoa 1M n°Y AMiM ,nÑ cr ,Naaemuºw on oxen, dtu mxwn ^` ;,ndN Compact discs are n" mvene'ºWm A,didi Advertisement Manager a.,Miw., 'AK becoming well -established and John Watkinson gives BOB NIBBS, A.C.I.I. 01-6613130 Pw"Illt a short overview of the xY ;. making of discs and the the Art MICHAEL DOWNING Nill method of playing them. F.N.C. More Ó 01-6618640 bY and some ntice ation .m Safa Omran's design for a plotter inform A,m constructional .te, video ASHLEY A camera/computer WALLIS 1.