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SPECIAL OFFER Real -time clock with 8K by 8 bit non -volatile memory www.americanradiohistory.com THERE'S A PHILIPS INSTRUMENT / THAT'S JUST RIGHT FOR YOU / AT ELECTRONIC BROKERS / OSCILLOSCOPES /

11 PM3256 FULLY RUGGEDIZED PM3219 STORAGE AND PM3206 COMPACT LOW COST PORTABLE 75MHZ REAL -TIME 50MHZ PORTABLE 15MHZ Designed for harsh field environments Dual Analogue storage with variable persistence Automatic triggering for stable trace Easily timebase with independent triggering Alternate Auto erase and auto store facilities High portable and lightweight TV triggering on line display of main and delayed timebase Trigger 2mV sensitivity across full bandwidth Alternate and frame Dual trace with 5mV sensitivity view as third channel display Multi sourced display of main and delayed timebases Easy Versatile X -Y measurement facility External triggering and trigger filters Tough compact unit auto mode triggering with level control Z modulation. with shoulder facilities combined £295.°° strap. £1, 55000 with easy operation. £2,99500

PULSE GENERATOR / FREQUENCY COUNTERS/ DIGITAL MULTIMETERS

111111111111. PM2519 MULTIFUNCTION PM6667/PM6668 HIGH MEASURING CENTRE PM5712 FAST RISE TIMES TO RESOLUTION COUNTERS 50MHZ Digital display with analogue bar graph Fast i Built in intelligence for easy operation 17 digit autoranging with manual option Relative Wide amplitude range 200mV to 10V 1Hz to high contrast LCD read out High stability X-tal measurements for all parameters Direct gain 50MHz frequency range Fast rise and fall times oscillator Range to 120MHz (6667), to 1GHz with selectable references Frequency to 1MHz, 4nS 10nS to 100mS pulse duration and delay (6668) High 15mV sensitivity Auto true RMS IEEE compatibility with Variable DC offset -5V to +2V Single, double triggering on 6667/01 6668/01 PR2519/51 2519/01 2519/51 and T/2 pulse modes. all waveforms. 749.00 A 95.00 version. £995. °° r £299 °° £495.00 LINE RECORDERS / X Y RECORDERS/ GRAPHIC PLOTTER

PM8251A/PM8252A SINGLE AND PM8154 INTELLIGENT X-Y PM8043 COST EFFECTIVE A4 RECORDERS DIN A4 DUAL PEN FORMAT Wide sensitivity 1my to 50V 250mm chart Up to 6 colour pen capability Writing speeds with up to 12 speeds Fast pen response and 5 time base speeds from 0.5 to 10s/cm up to 400mm/s Instruction set simplifies accuracy Standard remote control facilities Sensitivity 2mV to 1V/cm in 9 calibrated ranges programming Electrostatic paper hold down Dip marker and inverter switch Zero High rigidity lightweight chassis High pen Specify B version for IEEE 488/IEC 625 filter suppression -110% to + 210%. speed accelerations Switchable low -pass Specify S version for RS232N24. 8251A 8252A for interference free recording Ergonomically 8154B 8154$ designed front 2 A 5.00 £75000£1,050.°° panel lay out. £1, ! £1,195.0° £1,1950° I Electronic Brokers Ltd., 140 -146 Camden Street, London NW1 9PB. Tel: 01 -267 7070 Telex 298694 Fax No: 01 -267 7363

For further information contact our Sales Office. All prices exclusive of carriage and VAT Prices correct at time of going to press. A copy of our trading conditions is available on request.

CIRCLEwww.americanradiohistory.com I FOR FURTHER DETAILS. Editor ELECTRONICS & PHILIP DARRINGTON Deputy Editor GEOFFREY SHORTER, B.Sc. 01 -661 8639 Technical Editor MARTIN ECCLES ire esswor 01 -661 8638 Projects Editor over 70 years in independent electronics publishing RICHARD LAMBLEY 01 -661 3039 or 8637 (lab.) May 1986 News Editor Volume 92 DAVID SCOBIE 01 -661 8632 Number 1603 KURIU Drawing Office Manager ROGER GOODMAN 01 -661 8690 FEATURES BETTY PALMER Advertisement Manager Fibre Optics '86 New directions for marine dlf Q 43 ASHLEY WALLIS 1 8 If you think fibre optics is not for 01 -661 3130 by J.D. Last you, this event might surprise you. MICHAEL DOWNING Despite the growth of modern 01 -661 8640 navaids, radio direction finding is Sensitivity analysis Northern and Midland Sales still in common use. 46 BASIL McGOWAN by J. Lidgey 021 -356 4838 Generally used for filter analysis, Classified Executive A technique is just as valid in 6800 board-5 SUSAN PLATTS many other branches of electronics. 01 -661 3033 by R.F. 2 Coates Advertising Production To conclude this series, a selection BRIAN BANNISTER of programming examples. Timing by remote control 51 (Make -up and copy) by P. Ferris 01 -661 8648 Self- contained, microprocessor - Electronics & Wireless World controlled timer for up to eight is published monthly programmer for the USPS NO 687- 540 Eprom 28 appliances, with 100 on -off settings. Apple ll Current issue price 95p, back issues (if available) £1.06, at Retail and Trade by P.B. Unstead and A. Counter, Units 1 &2, Bankside Industrial Blunden Measuring tape speed 55 Centre, Hopton Street, London SEl. Expanding the Apple: the second in by M.E. Theaker Tel. 01 -928 3567. a series of lab. interfaces. Available on microfilm; contact editor. A simple and accurate method of By post, current issue £1.30, back issues ensuring the correct speed of (if available) £1.40, order and payments to EEP Sundry Sales Dept. Quadrant cassette tapes. House, The Quadrant, Sutton, Surrey SM2 5AS. Tel. 01 -661 3378. An introduction to 3D graphics 36 Editorial & Advertising offices: 1Obit digital recorder 56 Quadrant House, The Quadrant, Sutton, by H.W. Gleaves by T. Loughlin Surrey SM2 5AS. Using microcomputer Basic to Telephones: Editorial 01 -661 3614. Using modern data -conversion i.cs, Advertising 01 -661 3130 01 -661 8469 produce "three dimensional" signals images in perspective. very low- frequency analogue Telex: 892084 BISPRS G (EEP) can be recorded on tape with high Facsimile: 01- 661 2071 (Groups II & III) accuracy. Beeline: 01 -661 8978 or 01 -661 8986. 300 baud, 7 data bits, even parity, one stop -bit. Type control -Q, then EWW to start; NNNN Special Offer to sign off. Subscription rates: 1 year £18 UK A battery- backed, real -time clock/calendar with a 64Kbit, non -volatile ram at a special and £23 outside UK. price of £35. It will hold data for ten years and keeps track of hundredths of seconds, Student rates: 1 year £11.40 UK and tenths, seconds, minutes, hours, days, date and year in computer or controller £14.10 outside UK. appears on p.27. Distribution: Quadrant House. The applications. A description Quadrant, Sutton, Surrey SM2 5AS. Telephone 01 -661 3248. Subscriptions: Oakfield House, Perrymount Road, Haywards Heath, REGULARS Sussex RH16 3DH. Telephone: 04444 59188. Please notify a change of address. News Communications USA: $49.40 surface mail. $102.60 6 31 wremited airmail. Business Press International Radio data next year commentary (USA). Subscriptions Office, 205 E. 42nd Digitally assisted Street, NY 10117. Jamming Overseas advertising agents: Arctic communications France and Belgium: Pierre Mussard, 18 IBA planning satellite Space outlook - 20 Place de la Madeleine, Paris 75008. service Thermionics ' C grepresa United States of America: Jay Won, programmer Feinman, Business Press International Ltd. Feedback 205 East 42nd Street, New York, NY 10017 21 Circuit ideas 33 - Telephone (212) 867 -2080 - Telex: Von Neumann 33 23827. Black boxes T.t.l. -to -cmos line driver USA mailing agents: Expediters of XY lotter Development interface the Printed Word Ltd, 515 Madison olytics and Quad switch as SR latch Ell Avenue, Suite 917, New York. NY Elect 10022, 2nd class postage paid at New distortion Fron cover shows examples of "3D" York. Postmaster - send address to the f provided by H.W. Cleaves and above. graphics New products 60 , 6'7 1986. described in his article starling on p.36. ©Business Press International Ltd ISBN 0043 6062

www.americanradiohistory.com RADIOCODE CLOCKS LTD SPECIALISTS IN ATOMIC TIME, FREQUENCY AND SYNCHRONISATION EQUIPMENT NEW PRODUCTS MINIATURE RUBIDIUM OSCILLATOR MODULE Lower power, fast warm up, optional output frequencies, programmable frequency offsets. RUBIDIUM FREQUENCY STANDARD High performance, compact and rugged instrument. 2U rack or '/, ATR case options. INTELLIGENT OFF -AIR FREQUENCY STANDARDS Microcomputer controlled instruments, directly traceable to N.P.L., precision ovened local oscillator, comprehensive monitoring and status information, real time synchronisation. LOW COST MSF FREQUENCY STANDARD Instant operation, directly traceable to N.P.L., self -contained portable unit. no scheduled frequency changes, 24 hr transmission, real time synchronisation I Off -air frequency Time code generators /readers Radiocode standards Record /replay systems Intelligent time systems Intelligent display systems Clocks Ltd* Caesium /Rubidium based Precision ovened oscillators Unit 19, Parkengue, clocks & oscillators Time /frequency distribution Kernick Road Industrial Estate, Penryn, Master /slave systems systems Falmouth, Cornwall. Tel: Falmouth (0326)76007 J ('A Circuit Services Associate Co.) CIRCLE 51 FOR Ft.I1THER DETAILS.

SPECIAL OFFERS Sonnenschein Dryfit A200. 12 v.d.c. 5.7ah.' 1 51 .7 x 65.5 x 94.5m/m New and Boxed. High Impact A.B.S. case can be CONTACT MULTIPOWER used in any position. £16.95 inc VAT & C/P. Cherrjr Owerty keyboard New Tektronix Data Recording Fan Cooled ASCII. Linear I.C. Test FOR: LINEAR POWER SUPPLIES I.C.'s SN7493AN Fixture 178 £500.00 Linear P.S.U. 240V input SN7400N etc: E12.50 C/P + 15- 15 8A per output 1.50 Tektronix 7A 12 Dual Trace N /Boxed £40.00 DC TO AC INVERTERS Bryans XY Recorder Amp £275.00 Gould Type D.C. Type 25000 A4 A4 £215.00. 379 240V Tektronix 1A5 Differental input 5V 40A -12 4A+ 15 Amplifier E60.00 11A Switch Mode P.S.U. UNINTERRUPTIBLE PSUs Die-Cast All Box .£55.00 C/P 5.0U 4 } " x 11," x 23" E2.00 C/P Tektronix 54/54c Dual Trace 50p Calibrated Pre -Amp £50.00 Kingshill Stabilised Metered IEEE PROGRAMMABLE PSUs P.S.U. Type 601 240V input Cossor CDU150 Dual Trace 0 -60V 0 -1A E50.00 O'scope c/w manual 35MHz CDC Hawk 5+ 5mb Hard Disk £165.00 Drive New & Boxed c/w Manual £250.00 Elliott Type B443 Rotary MULTIPOWER Electronics Ltd. Fairchild 8 m/m type 70/07 Attenuator E45.00 Suitcase Type Projecter c/w Sharp MZ80A computer c/w Audio Amp = Len's Carrying MZ80AEU expansion Unit Rack Case 19" x 15" o 7 } ". 01- 6682898 Case 240V £19.95 C/P 3.00 £100.00. Data Books £16.00 C/P 3.75

AMF Plotter & Brumfield 12 Comark Digital Thermometer 26 CHIPSTEAD VALLEY RD, COULSDON VDC Relay. 240 VAC 5A Res Telequipment D67 O'scope Type 3000. - 195 to Dual Trace t e only 2 P /co E3.25 C/P 50p D67 Esc o + 1100 °C Data Ava. 75 inc CR3 3RG Thermal Coup TWX 926395 12 -0 -12 2A per /winding Krohn-Hite Corp = Wide Band 230V Prim: 2.50 C/P 1.00 DC-Imc. 10 Watt Amplifier. Texas Inst. Pulse Generator C1 RC I.I: 78 FOR FURTHER DETAILS. Type DCA10 £125.00 Type 6613E Data Ave 0- 12 -0 -24V 230V Prim: £60.00 E2.95 C/P 50p. 30V. 25A 240V Input Linear 20-22V 2A 230V Prim: P.S.U. Kingshill £30.00 CIP Bruel & Kjoer Electronic Volt £5.50 C/P 75p 9.50 Meter Type 2416.2 - 200000Hz £85.00 International Light 1L600 9 -0 -9V 1A 230V Prim: £1.95 Research Photo -Meter c/w C/P 50p Hewlett Packard 180A Seeéé u¢ary Flassh Intergrater 6610 £120.00 O'scope C/W 1801A D /chn 230V/115V Auto 50MHz Vert Amp + 1821A Transformers 500W £23.95 24V. 4 -8A 240V Input Linear Time Base & Delay Gen: with C/P 3.00 P.S.U. New & Boxed £19.95 Data Rack Mount with Data. C/P 3.50 £550.00 Universal Coupling Arms ideal Farnell Fan Cooled ? for Robotics 4" Closed Switch Approx E2.00 C/P 25p Mode 240V Input + 5.10A Lyons Instruments pulse - 5.1A + 12.3A - 12.1A generator, type PG -2E Stadt 10MHz. Cetronic Ltd. Line Conditioner , £28.00 C/P 3.00 50Hz Input Frequency Radical new Minimum Machining Concept Linc -Ace system 240V -20% + 10% 5KVA Prestell Adaptor Model P1 C/W Infra Red Remote Control 20:8 Amps £350.00 Keypad inc all Electronic's. C.P.U. Isolation Transformer will delight all users of small /medium size metal enclosures. Modem 1200 Bauds Rate. P.S.U. U.H.F. Modulator. Also, accessories to tackle R.F.I., H20, wall- mounting, Tektronix Type S.1. Sampling I.C.'s. AY- 3- 1015D. AY- 3- 9710HK. PIC 1650A -532 heatsinking etc. Sizes: Tiny to extended eurocard. Heads £200.00. TY16502. AY -3 -9725 New & Boxed. £15.95 C/P 3.00

CATLOGUE L LINCOLN BINNS LTD FIELD ELECTRIC LTD. NSA FROM: 3 Shenley Road, Borehamwood, Hens WD6 1AA. 01- 953 -6009 8 Official Orders /Oversea's Enquires Welcome /Telephone Orders Accepted. Open 5 Days 9am /5pm. Please Ring for C/P details not P.O. Box 110, Haywards Heath, West Sussex RH I7 5Yti Tel- (0444) 451418 shown. All prices Inc: 15% VAT unless stated. CIRCLE 48 FOR FURTHER DETAILS. CIRCLE 66 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com This is just a sample of our huge FG 504 40MHz Function Generator £1250 PG 501 Pulse Generator £125 inventory - contact us with your Marconi Instruments PG 502 Pulse Generator £1000 requirements. PG 505 Pulse Generator £150 ATE SYSTEM 80R PG 506 Constant Amp. Generator £1500 OSCILLOSCOPES Analogue /Digital Station PG 508 Pulse Generator £900 Hewlett Packard MINT CONDITION RG 501 Ramp Generator £100 1715Aupt101 200MHzScope E1950 SC 501 /2/3 Scopes ,u3£350 1980B opt 150, 810, 860 Scope System £4950 MLP £80,000 SG 502 Signal Generator £325 Tektronix SG 504 Signal Generator £1500 212 Miniscope500KHz E350 OUR PRICE £59,950 SG 505 Signal Generator £260 2445 150MHz 4 Channel Scope £2475 TG 501 Time Mark Generator £1350 465B/DM44 100MHz Scope DMM £2000 SIGNAL SOURCES TM 501 Mainframe £320 465B 100MHzScope £1450 Hewlett Packard TM 503 Mainframe £320 475A 200MHzScope £2350 214A Pulse Generator £750 TM 504 Mainframe E375 475 150MHzScope £2000 8007B Pulse Generator £950 TM 506 Mainframe E325 475A/DM44 200MHzScope/DMM £2750 8011A Pulse Generator20MHz £550 TM 515 Mainframe £400 485 350MHzScope £4950 8015A opt 02 Pulse Generator £1500 PACKARD COMPUTERS Generator HEWLETT 634 opt 1.20 Display Monitor £750 8616A UHF Signal 2631 B opt 005. 017, 019 Printer £650 7603 100MHzMainframe £1950 1800- 4500MHz £2750 3497A opt 001 Data Acquisition Unit E2950 7704A 200MHzMainframe £2850 86260A Sweep Generator Plug -in 6940B Multiprogrammer £1495 7854 Waveform Processing Mainframe £11000 12.4 -18GHz £3500 7910H opt 015 Disk Drive E2000 7904 500MHzMainframe £6850 8690B Sweeper Mainframe £950 E500 £475 9862A Plotter A large selection of 7000 series plug -ins available at up to 4204A Digital Oscillator 9915A Computer £850 6046 saving on list. Please call for quotations. 3314A opt 01 Function Generator £2500 Also available:- 9816A 9825S 9825T 9826A 3325A Function Generator £1950 9835A 9836A 9845S 9845B 9845C -150 ANALOGUE METERS Marconi Fluke 9827C 9827T TF 2002B AM /FM Signal Generator £995 887AB Differential Voltmeter £850 GENERAL PURPOSE T & M £750 TF 2006 AM /FM SignalGeneratorlGHz £1950 931B Differential Voltmeter Wavetek Farnell Marconi 166 50MHz Pulse /Function Generator £1500 SSG 520 + TTS 520 Transmission Test Set £4275 TF R F £550 2603 Millivoltmeter 184 5MHz Sweep Generator £650 Fluke ANALYSERS 195 Sweep Generator 5MHz E595 7220A Comms. Freq. Counter £495 Anritsu G. P. Industrial MS 62B Analyser TEKTRONIX G.P.T.E. MFL373 Fault Locator. MINT £395 Spectrum ENORMOUS SAVINGS NEW LOW PRICES- SAVE 10KHz -1700 MHz £7250 - P 9030 EPROM Programmer. MINT £450 UP TO 80% Hewlett Packard Hewlett Packard AM 501 Op. Amp. £75 Analyser £600 3437A High Speed D.V. M. £1250 332A Distortion DC 503 Counter £75 1615A Logic Analyser £950 3456A Systems D.V. M. £1500 DC 504 opt 01 Counter £95 nn RA opt 01 Modulation Analyser £4800 7ACnA A * fl.,.n £350 8903A DC 508 Counter £125 182T + E9350 3468A 51/20igitHPILD.M.M E395 8559A SpectrumAnalyser DC 508A Counter E500 3582A Spectrum Analyser £7750 8746B S Parameter Test Set £7500 OD 501 Digital Delay £300 7475A opt 001 Plotter £1275 Marconi DM 501 opt 02 DigitalMultimeter £75 TF Analyser £850 Marconi 2330A Wave DM 502A opt 02Digital Multimeter £100 TF Automatic Distortion Meter £450 TF 1313A LCR Bridge 0.1% E750 2337A FG 501 Function Generator £95 Modulation Meter E950 TF 2702 Inductor Analyser E950 TF 23005 FG 502 Function Generator £150 TF 2809 Dateline Analyser £650 TF 2807A PCM Tester £1350 Radiometer TF 2905/8 TV Pulse Generator E750 BKF 10 Automatic Distortion Analyser llbktronix + REC61 Plotter £1500 520A Vectorscope(NTSC1 £3750 Thandar 521A Vectorscope (PAL) £4250 TA 2160 LogicAnalyser 16 channel. MINT £950 690SR Colour Monitor £ 1500 Tektronix 576 Curve Tracer from £5000 -£7500 308 Data Analyser £1750 Ipr S1 Sampling Head £850 H. V. WM 4905 Mixer Set (49114921 New £6000 I 26015 40KV Probe (New) E400

ffC/RONIC BRAY

All prices are exclusiveisESOURCE of VAT and correct at time of going to press Carriage and packing charges extra A copy of our trading conditions is available on request ó o o o o o Electronic Brokers Ltd, 140 -146 Camden Street, London NW1 9PB o ° ° Telephone:P 01 -267 7070 Telex: 298694 Fax: 01 -267 7363 Brlorsol I o l o CIRCLE 80 FOR FURTHER DETAILS.

n . S .T 1986 3 I I I www.americanradiohistory.com LOW COST CAD ATTENTION ALL ELECTRONICS CIRCUIT DESIGNERS!! DRAUGHTING IBM PC, BBC MODEL B and SPECTRUM 48K BBC MODEL B ANALYSER I and II compute the A.C. FREQUENCY RESPONSE of linear (analogue) circuits. GAIN and PHASE, INPUT IMPEDANCE, "DRAWER drawings to be created, and modified, OUTPUT IMPEDANCE and GROUP DELAY (except Spectrum version) I" enables quality easily and with the minimum of hardware. Positional input is are calculated over any frequency range required. The programs are in quickly, by standard joystick. All of the major mprogram elements are written use regularly for frequencies between 0.1 Hz to 1 .2GHz. The effects in machine code giving exceptional speed of operation. on performance of MODIFICATIONS to both circuit and component values can be speedily evaluated. "`_ ='` °" . ' ° "' Circuits containing any combination of RESISTORS, CAPACITORS, ' "' °- °° r INDUCTORS, TRANSFORMERS, BIPOLAR AND FIELD EFFECT °'.' -- " " "" ""'i' " TRANSISTORS and can . : OPERATIONAL AMPLIFIERS be simulated - ,.. .. alo o &' , up to 60 nodes and 180 components (IBM version). ..,,= _ ". FA:I 1 - ._f_ 11 Ideal for the analysis of ACTIVE and PASSIVE FILTER CIRCUITS, !* q 111 AUDIO AMPLIFIERS, LOUDSPEAKER CROSS -OVER NETWORKS, ; i - WIDE -BAND AMPLIFIERS, TUNED R.F. AMPLIFIERS, AERIAL _,.. -.,

MATCHING NETWORKS, TV I.F. and CHROMA FILTER CIRCUITS, " ° ' LINEAR INTEGRATED CIRCUITS etc. - ' ' STABILITY CRITERIA AND OSCILLATOR CIRCUITS can be evaluated FEATURES by "breaking the loop ". it Rubber Banding for drawing lines. MIMUM HARDWARE REQUIRE Y Solid or Dotted lines types. tz BBC Model B. Tabular output on Analyser I. Full graphical output, increased circuit size and active component library facilities on Analyser II. Circles, arcs and partial or complete * Single or Dual Disc Drive - 40 or 80 elipses. track. Chc,:k out your new designs in minutes rather than days. . Vertical or Horizontal Text. tr T.V. or monitor. ANALYSER can greatly reduce or even eliminate the need to breadbord tr Pan and Zoom. * Games Joystick with "fire button" new designs. * Merging of drawings and library symbols it Dot Matrix Printer (Epson 80 series or Full AFTER SALES SERVICE with TELEPHONE QUERY HOT LINE and from disc. Epson compatible - BBC default mode FREE update service. Û Snap to a user defined grid. preferable). Absolute or Relative cursor coordinates Used by INDUSTRIAL, GOVERNMENT, and UNIVERSITY R & D displayed on screen. DEPARTMENTS worldwide. IDEAL FOR TRAINING COURSES. VERY tr Output to standard dot matrix printer. EASY TO USE. Prices from £ 20 - £195. it price - £45 no VAT. For further details please write or phone quoting Dept W.W. MEDMII@ED (\,1)11G r`U'OSa7A).0' ggaZ 1 9A Crown Street, St Ives, Huntingdon, Cambs. PE1 7 4EB. Telephone: St Ives (0480) 61 778 Telex: 32339 CIRCLE 65 FOR FURTHER DETAILS. USED TEST EQUIPMENT COMPUTER PRODUCTS Fully guaranteed * Performance to original specification * Wide range of instruments & computer products CARSTO 943 4411 1 Ring for latest stock information %el trig - 99, Waldegrave Road, Teddington, Middlesex TW11 8LL. ELECTRONICS LTD. Telephone 01- 9434477. Telex 23920 (Euhire) Used test equipment and computer specialist 1 CIRCLE 77 FOR FURZ HER DETAILS. KESTREL ELECTRONIC A, COMPONENTS LTD. ' ' All Items guaranteed to manufacturers spec. - ' Many other Items available. o, 'Exclusive of V.A.T. and Post and Package' l

1 + 1 + 1 + 50+ 50+ 1 % 74LS00 .13 .12 74L5273 .46 .42 2716 2.10 1.90 74LSO4 .13 .12 74LS373 .43 .45 3.50 Pic) -Lire y 27C64 3.00 Quairant Librar 74LS08 .15 .13 74LS374 .48 .45 2764 -250 1.90 1.80 CARS BOATS PLANES 74LS14 .19 .17 74LS393 .65 .45 27128.250 2.50 2.20 6502 3.30 2.80 74LS541 .45 .35 27256 -250 4.00 3.60 Over a million photographs and transparencies 8522 3.30 2.80 8155 1.50 1.30 6116LP -3 1.48 1.25 74LS138 .30 .25 8251 1.50 1.30 6264LP -3 2.40 2.30 from the turn of the centuryry to the ppresent day; 74LS139 .30 .25 8253 1.50 1.30 4164 -15 1.00 0.90 74LS157 .27 .24 8255 1.50 1.30 41256 -15 2.60 2.50 cutaway drawingsg and illustrations; colour TL071 .30 .26 6810 1.30 1.10 Z80ACPU 1.40 1.00 prints of and TL084 .56 .48 8821 1.40 1.25 Z8OACTC 1.50 1.10 civil military aircraft; directories 74LS140 .50 .42 6850 1.50 1.25 Z80AP10 1.50 1.20 from the early 1800s and much more besides 74LS244 .48 .45 4 neg Xtels .70 .55 Z8OADMA 3.00 2.60 74LS245 .50 .43 6 neg Xtels .70 .55 LM324 23p 20p for advertising and PR agencies, authors, All memory prices arefluctuating daily, please phonetoconfirm prices. publishers, TV programmers and solicitors. 178 Brighton Road, Interested? Then write or telephone QPL at Purley, Surrey CR2 4HA Quadrant House, The Quadrant, Sutton, Tel: 01. 668 7522 Surrey SM2 5AS (Tel: 01- 661 3427 '8 ). 4 ELECTRONICS &WIRELESS WORLD MAY 1986

www.americanradiohistory.com MEMORIES DOT n x Tx rx BARGAINS HONEYWELL PRINTERS

07072802 28 PIN LOW PROFILE SOCKET

PRODUCT CODE DESCRIPTION DEVICE PRICE DEVICE PRICE L11 80 col. Parallel OF 150 2532 -30 4.50 4116-15 1.50 L 1 1CQ 80 col. Parallel OF & NLQ 190 4.20 4116-20 1.20 2532 -45 L11/I 80 col. IBM Comp. OF 150 3.45 4164-15 1.40 2716 -35 L12 CQ/I 80 col. IBM Comp. I/F & NLQ 200 2.95 4532-20 1.83 2716 -45 L31CQ 132 col. Parallel OF & NLQ 240 4564-15 4.33 2732 -25 5.95 L32/I 132 col. IBM OF 230 5.45 6116 LP3 1.99 2732 -35 L32CQ/I 132 col. IBM Comp. I/F & NLQ 290 4.50 8118 1.92 2732 -45 S11 80 col. Serial I/F 150 1.85 81256-15 2.95 2764 -25 S31CQ 32 col. Serial OF & NLQ 240 8264-12 2.45 27128 -25 2.50 RIBHW Black Fabric Ribbon 1.00 27256 -25 6.15

COMPONENTS SHEET FEEDERS ... PART NO. 1 + PRICE PART NO. 1 + PRICE PROCESSORS & PERIPHERALS 4000 CMOS THAT WORK!!! 6502 4.60 4000 0.40 6502A 5.60 4001 0.32 6520 3.25 4002 0.32 1.02 QUME ZJ4D 8520A 3.85 4006 RICOH 6522 4.18 4007 0.40 Qume 8 -10 -11 RICOH 1300 6522A 7.28 4008 0.79 ORDER Z103 6532 4.92 4009 0.76 ORDER Z106 6532A 5.41 4010 0.76 /RICOH 1600 6551 5.90 4011 0.32 ORDER Z107 HC CMOS FAIRCHILD FAST 74HCOON 0.38 74FOOPC 0.61 74HCO2N 0.38 74F02PC 0.61 74HCO3N 0.48 74F04PC 0.70 74HC04N 0.38 74F08PC 0.61 74HC08N 0.38 74F109PC 0.77 74HC107N 0.48 74F11PC 0.61 74HC109N 0.45 74F138PC 1.54 74HC1ON 0.48 74F139PC 1.54 74HC112N 0.51 74F151 1.54 LS III FERRANTI DATA CONVERTERS 74LSOON 0.25 ZN404 0.55 74LS1ON 0.25 ZN423 0.90 JUKI 74LS02N 0.25 ZN425E -8 3.45 NEC TOSHIBA ALL JUKI 74L503N 0.25 ZN425J -8 7.31 SPINWRITER TH2100 MODELS 74LSO4N 0.25 AN426E -8 2.00 2000/3500/8800 P1351 ORDER Z111 74LS05N 0.26 ZN427E -8 5.90 ORDER Z105 ORDER Z115 74LS08N 0.25 ZN427J -8 11.54 74LS09N 0.26 ZN428E -8 4.30 74LS1ON 0.25 ZN428J-8 8.91

All prices exclude VAT and carriage and are subject to stock HI TECH availability. CO/VIPONEM

ELECTRONICS & WIRELESS WORLD MAY 1986 5

www.americanradiohistory.com NEWS COMMENTARY Radiodate to begin next year From the autumn of next year,

programme -labelling data will 93.5 BBC Wrotham be carried by all BBC f.m. 93.9 BBC Oxford 92.5 BBC Guildford 94.9 BBC R. London radio stations in England. The 91.7 BBC Oxford 95.2 BBC R. Oxford extra signals will make possi- 91.3 BBC Wrotham 95.8 ILR Capital eon 90.3 BBC Guildford 98.8 ILR Guildford (County Sound) ble the development of push 89.5 BBC Oxford 97.0 ILR Reading (210) button radio with B9.1 BBC Wrotham 97.3 ILR LBC sets fully 88.1 BBC Guildford 97.8 ILR Dunstable (Chiltern Radio) automatic tuning. This, the 103.8 BBC R. Bedfordshire (Dunstable) BBC hopes, will put an end to the increasing difficulty many ieesiwea:létr' listeners have in finding the stations they want. I1I.,IW®F:.48EBSOlediB16. I_ _ In the initial phase, to begin in September 1987, the new ma. Radio Data Signalling (RDS) 0:1111111111111111111 11111I111'i111111 transmissions will carry five aalleeel..eIll1 lla.elMell111Il items of information: a programme identification code, very frequently repeated, 88.3 BBC Wooburn 89.9 BBC High Wycombe 104.9 BBC R. Berkshire (High Wycombe) which uniquely identifies the 90.5 BBC Wooburn 104.6 BBC R. Surrey transmitting station: 92.1 BBC High Wycombe 104.4 BBC R. Berkshire (Reading) this helps 92.7 BBC Wooburn 104.1 BBC R. Berkshire (Hannington) the receiver to find the service 94.3 BBC High Wycombe 103.4 ILR Henley 94.8 BBC R. Berkshire (Henley) 102.9 ILR Hannington chosen by the user and to 98.4 BBC R. Berkshire (Windsor) 102.8 ILR Oxford select the strongest signal. 98.2 BBC Aylesbury 102.1 ILR London 3 a programme service code, a 97.7 BBC Guildford 101.7 IBA High Wycombe 97.9 BBC Wooburn 101.3 IBA Oxford label of up to eight characters 98.7 BBC Wrotham 100.9 IBA Wrotham which could be displayed on 99.1 BBC Oxford 100.1 IBA Wooburn 99.5 BBC High Wycombe 99.9 IBA Guildford the receiver (e.g. "BBC YORK ") or passed to a voice The radio jungle to synthesizer. the west of London: stations shown below the diagram have yet to make their appearance. RDS will bring in the ones you want by a list of alternative frequen- tuning and retuning the set automatically. cies for the same service: with car radios, for example, this could speed up the retuning casting Union after a decade of less to gain from automatic process on passing from one technical work and inter- tuning than a national broad- transmission area to another. national discussion. And this caster who carries the same In brief Where networks are split month the system is expected programme on many frequen- Up to 2 x 109bytes of between wavebands, the list to be adopted as a world stan- cies. information can be stored on could include l.f. and m.f. dard both sides of a 12in optical by the CCIR. The cost of self- tuning RDS stations. disc and 600MB on a 4.75in The data stream, at 1187.5 sets will depend on whether 'other network' information compact disc. Such discs are bit /s, is carried at 57kHz with a i.c. makers are prepared to to allow, say, automatic switch- 1 likely to have a similar deviation of -2kHz of the commit themselves to the ing to another station when a impact on information main f.m. carrier. It can co- system. But the BBC says the traffic announcement is to be technology as the exist with mono or stereo pro- prospects for its success are broadcast. microcomputer, according to a grammes and with most exist- good: a recent survey found clock time and date. ing report from the US Technical subcarriers offered by that over 70% of adult listeners These features are cheap to Information Service. The broadcasters, although some would be prepared to spend an implement, says the BBC, 57kHz systems in report includes a detailed the USA extra £15 on a basic £25 port- because they require no would need assessment of optical disc to move to accom- able set if it could have RDS. editorial input by the broad- modate it. technology and is available in However, the MBS And users of car radios are caster. radio -paging the UK from Microinfo Ltd, system used in said to have found the idea of But if RDS is a success with Alton, Hants. Sweden is now being changed RDS especially attractive. audiences, a range of other to make it compatible with services could be added later. RDS. However, although several These Japanese firms are said to be might include a text Several European broad- Kef Electronics, makers of block of up to 64 working on prototypes, there characters to casters are working on plans loudspeakers, are to have a carry programme details, are no signs yet of a rush to for RDS, although at present new head of research in the phone -in numbers, - launch RDS sets. And in news only Sweden is running a person of Dr Richard Small, flashes or even advertisements: Britain, Mullard tell us they service - an experimental who has left his post as a identification codes for indi- have no plans at present to pro- operation on one channel only. senior lecturer in the vidual programmes: a duce the necessary i.cs. and In Britain, the IBA carried out University of Sydney. He is the telex -like text channel for tests of RDS last year in the Full details of the RDS for- author of Direct radiator downloading programme fact - London area but has not yet mat are given in an EBU docu- electrodynamic loudspeaker sheets or computer data. decided to launch a service. No ment, "Specification of the systems, which has been The BBC's RDS transmis- doubt the commercial broad- radio data system RDS for reprinted four times and sions meet a specification laid casters, as a loose federation of VHF /FM sound broadcasting ", received a Silver Medal award down by the European Broad- separate stations, have rather technical publication 3244/E. from the AES. 6 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com Digital assistance for tv signals A good Experiments at BBC's component is to carry 625 -line tv systems which Research Department have information about which parts have associated digital idea? Patent produced a system for of the picture are static and capacity, such as the transmitting analogue picture which are moving. It is MAC /packet family of it! signals along with high data - possible to repeat the static transmission standards. says the restricts the All too often, rate digital signals carrying information and only transmit However this use Chartered Institute of Patent control or supplementary the changing part of the freedom to exploit the full Agents, adequate safeguards DATV compared information about the picture. picture. Such techniques are potential of are not taken to prevent ideas to facilitate the One application of this common in bandwidth- saving with its use being poached by others, and DATV HDTV Digitally- assisted tv (DATV) exercises, but the transmission of many entrepreneurs come using more than 1000 could be to reduce the experiments have shown that systems unstuck in the race to get bandwidth of high- definition tv it is possible to apply them to lines. their idea to the marketplace. Sandbank, deputy so that it can be HDTV with a bandwidth Charles The most common mistake is said: accommodated within a single reduction by a factor of director of research to tell others about the idea "DATV is a powerful DBS channel, previously between two and four. before asking for professional is technique for squeezing planned for 625 -line tv Another example the advice, only to find that as a DATV HDTV signals through the services. is a reconstruction of a result all hope of protection bandwidth compression sequentially- scanned picture bottleneck of transmission has then been lost. the sort of technique intended for use where, to save bandwidth in channels, using Manufacturers are well has that will be with high quality tv signals. transmission, the signal technology aware of the legal wrangles homes in the The digital control signals been converted from available in our which can follow discussions I am confident that it assist in the reconstruction of sequential to interlaced 1990's. of purveyors of unprotected role in the picture without scanning. will play an important ideas and many will refuse to degradation. One example of DATV can also be used to establishing a European negotiate with inventors until for the use of the digital improve the performance of broadcasting strategy the proper legal protection has HDTV." been applied for. To counter these problems the Institute has launched a After Alvey campaign to help inventors and entrepreneurs bring their Light at the end The Information Technology ideas safely into fruition. A (1986) Committee has been working party of patent agents of the tunnel? formed to look into ways of and financiers is looking into preserving and maintaining the whole area of invention, The Council of the Electronic were to be avoided, equipment the momentum generated by and the funding of projects in Components Industry manufacturers must recognise the Alvey programme. Sir their early stages. Federation (ECIF) reported that the 'supply tap' cannot be Austin Bide, chairman of Patent agents believe they recently that their industry turned on and off rapidly, and British Leyland and former must promote a better seems to be pulling out of the that ordering must be planned chairman of Glaxo is heading a understanding of the forms of recession. Most sectors accordingly. The ECIF were committee drawn from the IT legal protection available for reported encouraging signs. In seeking urgent talks on this industry, IT users and new ideas and of the paticular the semi -conductor with customer trade academics. The new registration systems involved. manufacturers noticed an associations. committee has been organized They have issued free leaflets increase in demand; enquiries It was agreed that glimmers by Sir Robert Telford, as introductory guides to for application- specific i.cs of light were appearing at the chairman of the Alvey steering patents, trade marks and particularly were encouraging. end of the tunnel, and the committee. A major task for registered trade marks, design is to a registration and design The council thought that lead - council concluded that overall the committee establish times might soon lengthen but prospects were for a proper balance between copyright, and service marks warned that another 'boom significantly better 1986 than national and European efforts for service businesses. and bust' cycle was in 1985. including the UK relationship Available from the Chap Lered nobody's interest and if it with Esprit, Eureka and Race . Institute of Patent Agents, The Committee is to report Staples Inn Buildings, London its findings by October 1st. WC1V 7PZ.

WALLCHART OF FREQUENCY ALLOCATIONS

It is over ten years since the original frequency allocation wallchart was produced and it is, of course, well out of date. Many changes have taken place during that time and it has been clear for some time that a continuing demand had to be satisfied. In response to repeated requests for a new chart, we have produced a new version, which will be presented as a loose insert with the June issue, on sale on Wednesday, May 21. Many schools, universities and commercial laboratories still have the original chart, and we expect a large demand for the new one. Readers may find it useful to place an advance order for the journal with their newsagents, or take out a subscription, to ensure that they do not miss this once-only opportunity.

ELECTRONICS & WIRELESS WORLD MAY 1986 7

www.americanradiohistory.com NEWS COMMENTARY

Electron beam writing on GaAs In brief

We have received bitter At its base in Towcester, microwave i.cs will also be frequency devices but also complaints from Plessey 3 -5 Group is installing possible. improve the signal /noise manufacturers of modems who a Cambridge Instruments The equipment allows the performance of current are frustrated by the red tape EBMF 10.5 electron -beam fabrication of fine geometries MESFETS at frequencies and delays in getting BATB tool. This will enable the by a highly focussed beam of down to X -Band. approval for their equipment. consistent production writing electrons to expose a specially Microwave power devices Nazir Jessa of Watford of gate lengths down to 0.2µm formulated resist, thus will also benefit; large device Electronics points out the on gallium arsenide metal reducing the size of the structures can have total gate Catch -22 situation that he is semiconductor field- effect features compared with that widths of several centimeters caught in with Watfords Le transistors ( MESFETS). The previously possible with photo- and gate lengths of 1µm. Such Modem: "If I wait for first product to benefit from lithographic techniques. devices are used in phased - approval before I put Le this abilty will be a 40GHz Computer control provides a array radars and as solid -state Modem on sale, I could find MESFET currently under high degree of automation. replacements of travelling that the technology is out of development. Direct writing of Such short gate lengths wil wave guide tubes. date. Alternatively I could sell features on monolithic not only lead to higher (am selling) the modem without approval and risk customer disatisfaction." According to Nazir the Knowledge base for Esprit situation is made more ridiculous because the device is constructed from BT A five -year project, funded by a prognosis based on the new area need to be found. approved components and is the European Esprit acquired knowledge. One This could also reflect back by actually being offered with a programme, is to be successful example has been providing insights into writing three -month free subscription undertaken on research into used in medical diagnosis. more conventional software. to Micronet, partly owned by knowledge -based systems. The software required is The work should be of BT. Such systems are one aspect intrinsically different from interest to all researchers in Similarly vociferous is Barry of `artificial intelligence' providing a conventional programs. In better Krite of DataStar research. Systems, They acquire order to apply it effectively in understanding of the way such distributors of the Magic knowledge from experts in a industry, a better systems operate. It should also Modem: "BT's marketing specific field; combine this understanding of the methods provide modes of operation in policy supposes that modems with codes of practice and /or and techniques for building applying similar techniques to without BATB approval are other rules and regulations, such systems is needed. Ways new areas and for increasingly potentially dangerous, despite and then programme a of applying the disciplines of complex applications. the fact that they themselves computer to analyse and give software engineering in this The work is to be led by STC. sell modems without approval. Until our modem is approved, customers such as government depatments and schools, who are obliged to buy approved Britain dominates the comms RACE products, can't by the Magic Modem." Barry is even more Yet another European manufacturing industry in competitive Community frustrated with the knowledge acronym to go alongside broadband communications market for telecommunications that the modem has been Esprit and Eureka is Race; and to accelerate the equipment into the next successfully tested in the BT Research in Advanced emergence of a viable and century. labs but is still awaiting Communications for Europe. official approval. The European Commission Ceefax, BBC's teletext has announced details of service is now using six lines in contracts to be awarded and IBA DBS the tv signal compared with Geoffrey Pattie, IT minister, plans service the four in previous use. This is very proud that: "there are The Independent Broadcasting John Witney, IBA's director speeds up the time it takes for more British participants than Authority if proceeding with general, warmly welcomed the the required page to come there are from any other plans to persuade contractors opportunity to provide round. The improvement is the member state. Of the 192 to provide up to three direct - additional services; "After result of the new computer participant, 52 are British. broadcasting-by -satellite much discussion as to how equipment which also British enterprises are leaders channels. This follows the DBS could be introduced to increases the efficiency of the in 14 of the 32 successful bringing into action of sections the ux, we are enthusiastic at system by taking over some of consortia and there is a British 37 to 41 of the Cable and the prospect. We shall be the `housekeeping' tasks from presence in 26. This shows Broadcasting Act which proceeding with all speed the contributing journalists. that Britain is ready, willing provide for the contractors to while aiming to ensure that There has also been and able to take a leading part make the financial and other the firmest possible basis is improvement in the subtitling in colaborative research in arrangements for the provision laid." service: it is now possible to Europe, which is important of satellite transponders, The service, if suitable transmit subtitles on both both for Europe and for subject to the specification of contractors are found, could channels simultaneously. The British companies." the IBA, which as broadcaster be broadcasting by 1990. It teletext signals are now The aim of the Race will be responsible for is likely to be funded by generated at the point of programme is to establish a ensuring that the services are advertising and /or programme origin, bypassing strong Community of high quality. subscription. the Ceefax computers. 8 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com ANALOGUE METERS LEVELL OSCILLOSCOPES LEVELL AC MICROVOLTMETERS TM3A/B £159/179 CROTECH SINGLE TRACE 20MHz 3031/36 £195/216 /div. 40ns-0.2s/div. Cal 0.2V. Component test. 16 ranges 150Vfs /500Vfs, accuracy 1 %+ 1 %fs+ 10/. 2mV- 10V 1.8kV 8x10cm. - 20dB/ +6dB scale ±3dB 1Hz -3MHz. 150mVfs output. for INSTRUMENTS 3031: CRT 1.5kV 5x7cm. 3036: CRT TM3A: 83mm scale. TM38: 123mm scale and LF fitter. CROTECH DUAL TRACE 20MHz (@2mV) 3132 £285 Cal 0.2V LEVELL BROADBAND VOLTMETERS TM6AB£249 /279 2mV- 10V /cm. Ch1 ±Ch2. X -Y mode. normal or TV trig. 16 LF ranges as TM3A/8 + 8 HF ranges lmVfs /3Vfs, 1kHz sq. 40ns -0.2s /cm. Auto, Component comparator. DC outputs. Z input. CRT 2kV accuracy 4% + 1 %fs at 30MHz. ±3dB 300kHz- 400MHz. 8x10cm. LEVELL DC MICROVOLTMETER TM8 £135 30MHz 3337/39 £425/570 28 linear ranges ±30V / ±300V and ±3pA/ ±300nA plus 2 CROTECH DUAL 105mV) ±Ch2. mode. log ranges for nulling. Output ±300mV at fs. 5mV- 50V /cm. Chl Signal delay. X -Y 40ns -1 s /cm. Auto, normal or single shot trigger. Cal 0.2V 10kV LEVELL MULTITESTER TM11 f 179 1kHz square. Z input. CRT 8x10cm. DC outputs. 50NV /500Vfs ac, 50pA /50OmAfs ac, 150yV /500Vfs dc, 3339: VDU mode. Component tester. 150pA /500mAfs dc, 0.20 to 100Gf2, lin /log null. HM203 £270 Diode /LED test. Optional RF, HV and Temperature. HAMEG DUAL TRACE 20MHz 102mV1 -5 2mV- 20V /cm. Ch2 ±Chu. X -Y. Cal 0.2V /2V 1kHz sq. test. LEVELL TRANSISTOR TESTER TM12 £199 2Ons -0.2s/cm. Auto, normal or TV trig. Component Transistor, diode and zener leakage to 0.5nA at 2V -150V. CRT 2kV 8x10cm. Long decay CRT £25 extra. Breakdown to 100V at 10pA, 100NA, 1 mA. Gain at £365 1&A- 100mA. Vsat and Vbe at 1mA- 100mA. HAMEG DUAL TRACE 20MHz (@5mV) HM204-2 1mV- 50V /cm. Ch2 ±Ch1. Sig delay. X -Y mode. LEVELL INSULATION TESTER TM14 £220 Y out. 10ns- 1.25s /cm. Sweep delay 100ns -1s. 2kV Log scale covers 6 decades 10MS2 -10782 at 250V, 500V, Cal 0.2V /2V 1kHz /1MHz. Z input. Comp. test. CRT 750V, 1kV; 1M -1TS2 at 25V -100V; 100k -100GO at 8x 10cm. 2.5V -10V; 10k -10052 at 1V. Current 100pA- 100NA. HAMEG DUAL TRACE 60MHz 1@5mV) HM605 £515 1mV- 50V /cm. Ch2 ±Ch1. Sig delay. X -Y mode. Y out. 5ns- 2.5s/cm. Sweep delay 100rms -1s. Cal 0.2V/2V DIGITAL METERS 1kHz /1MHz. Z input, Comp. test. CRT 14kV 8x10cm.

LEVELL DIGITAL THERMOMETER DT1K £44 HAMEG DIGITAL STORAGE 20MHz HM208 E 1300 - 120°C/ +820°C, acc 0.2 % ±1 °C. 3 digit 8.5mm LCD. 1mV- 50V /cm. Ch2±Ch1. Single shot and X -Y modes. Two 2K memories. A standard Type K thermocouple socket is fitted. Bead 20ns -0.25s /cm. 20MHz sampling. 14kV 8x10cm. couple is supplied. Battery life >3000 hrs. Plotter output 0.1V /cm, 10s/cm. CRT

1 V209 E680 LEVELL DIGITAL CAPACITANCE METER 7705 £49 HITACHI BATTERY DUAL 20MHz @5mVl 1kHz. 0.1 pF-2000pF, acc 0.5%. 3'V: digit 12.7mm LCD. lmV- 12V /div. Ch1±Ch2. X -Y mode. Cal 0.5V SOns -0.5s /cm. Auto, normal or TV trig. Internal THURLBY DIGITAL CAPACITANCE METER CM200 £89 rechargeable belt. or mains. CRT 1.5kV 5x6.3mm. 1pF to 250014F, acc 0.2 %. 41/2 digit 9mm LCD. Fast settling. 3 readings per second. Mains/battery. HITACHI DUAL 20MHz V212/222/223 £299/395/450 lmV- 12V/cm. 20MHz at 5mV. Ch1±Ch2. X -Y. Ch1 HC DIGITAL MULTIMETERS HC5040/5040T E37/39 output. 100ns -0.5s /cm. Auto, normal or TV trigger. Z input. CRT 2kV 8x10cm. 31/2 digit 12.7mm LCD. Up to lkVdc, 750Vac, Cal 0.5V 1kHz square. 10A, 20MR. Resolution 1000V, 100nA, 10mO V222: Plus DC offset and alternate magnify function. 15040T: 100mí21. Buzzer. dcV 0.25 %. Battery life V223: As V222 plus sweep delay 1ys- 100ms. 2000hrs. 5040T: has a TR test. HITACHI DUAL 40MHz (05mV) V422/23 £580/650 THURLBY DMMs 1503/1503HA/1504 £169/185/199 As V222N223 but 40MHz, 20ns/cm and 12kV on CRT. 4% digit 9mm LCD. Up to 1.2kVdc, 750Vac, 10A, 32MS2, V650F £780 4MHz. Resole. 101N, 10nA, 10mO. Mains / battery. MACH TRIPLE 60111Hz (05mV) 1503: dcV 0.05 %. 1503HA: 0.03 %. 1504: True rms ac. Ch1 /Ch2: lmV- 12V /cm. Trigger Ch3: 0.2V/cm. Chi output. Dual time bases 5ns -0.5s/cm and 5ns- 50ms/cm. THURLBY INTELLIGENT MULTIMETER 1905a £349 Signal and sweep delay. CRT 10kV 8x10nxn. S'h digit 13mm LED. Up to 1.1kVdc, 750Vac, 5A, 21MS2. Resoln. 11N, 1nA, Una. dcV 0.015 %. Computing and HITACHI QUAD 100MHz (4115mV) V1050F 109 storage functions. RS232 /IEEE interface options. Chi /Ch2: 0.5mV- 12V /cm. Trigger Ch3/Ch4: 0.2Vf /cm. Dual time bases 2ns-0.5s/cm and 2ns- 50ms /cm. Signal and sweep delay. CRT 20kV 8x10cm.

COUNTERS & OSCILLATORS HITACHI QUAD 100MHz V 1070/1100A f 1580/2390 Ch1 /Ch2: 1mV- 12V /cm. CH3 /Ch4: 0.1V -0.5V /cm. COUNTERS MET 100/600/1000/1500 (99/126/175/199 Dual time bases 2ns -0.5s /cm and 2ns- 50ms /cm. 18kV 8x10cm. 8 digit 0.5" LED. 5Hz up to 100 /600/1000/1500MHz. LEVELL DECADE BOXES Digital display of set values. CRT Resolves 0.1Hz. Sensitivity 5mV up to 10MHz. Low pass V1100A: Digital display of ACV, DCV, frequency. fitter. Mains /rechargeable battery powered. 1 £ 1350 C410 : 10pF to 111, 110pF, acc % ±2pF. £49 HITACHI DIGITAL STORAGE 10MHz VC6015 £49 ±Ch2. shot and X-Y modes. LEVELL FUNCTION GENERATORS TG302/3 £136/236 R401/410 : 4 decs. 10 or 1012 steps, acc 1%, 2.5W 5mV- 12V/cm. Ch1 Single £63 Two 1K memories. 0.02Hz -2MHz in 7 ranges. Sine, square, triangle, pulse and R601/610 : 6 decs. 10 or 100 steps, acc 1%, 2.5W 10n -0.5s /cm. 1MHz sampling. £75 5- 10s /cm. CRT 2kV 8x1Ocm. ramp 20mV to 20Vpp from 5062. DC offset 0 / ±10V. TTL R601S : 6 decades. 10 steps, acc 0.3 %, 2.5W Plotter output 1V/cm. 1 out put. TG303 also has a CMOS output and 6 digit 10MHz R701 : 7 decades. 10 steps, acc %, 2.5W £72 counter with INT/EXT switch. HITACHI DIGITAL STORAGE 40MHz VC6041 £3850 1mV- 12V /cm. Ch1±Ch2. Single shot and X -Y modes. 4K memories. LEVELL RC OSCILLATORS TG152D/DM £99/125 20ns -0.5s/cm. 40MHz sampling. Two BENCH POWER SUPPLIES 12kV 3Hz- 300kHz. 5 ranges, acc 2 % +0.1Hz up to 100kHz, Plotter output 1V /cm, 2- 10s/cm. CRT 8x10cm. 3% at 300kHz. Sine or square <2000V to 2.5Vrms. Dis-tn. 179 <0.2% 50Hz- 50kHz. TG152DM has an output meter. THURLBY SINGLES PL154/310 /320 (159/125/155 THURLBY 8 CHANNEL MULTIPLEXER 0M358 f 0.5" LED digit meters, acc 0.1 %, resoln. 10mV, ImA. Increases any oscilloscope to 8 channels. Choice of trigger DC- LEVELL RC OSCILLATORS TG200D/DMP £139/175 <0.01 % change for 50% load change. Remote sense. from any channel. Response 35MHz. 1Hz -1MHz. 12 ranges, acc 1.5% +0.01Hz to 100kHz, 2% 154: 0-15V 0-4A. 310: 0-30V 0-1A. 320: 0-30V 0-2A. at 1MHz. Sine or square outputs <200NV7Vrms. Distortion <0.05% 50Hz- 15kHz. Sync output >1V. THURLBY DUALS PL3100MD /3200MD £269/339 LOGIC ANALYSERS TG200DMP has output meter and fine frequency control. Two 0-30V 0-1A (2A on 3201 with isolated, series tracking, series or parallel modes of operation. £395/495 LEVELL DECADE OSCI.lATOR TG66A £330 THURLBY LOGIC ANALYSERS LA160A/8 for BI. 0.2Hz- 1.22MHz. 5 ranges. 4 digits, acc 0.3% THURLBY TRIPLES PL310K/320K £275/345 16 data charnels. Clock DC -10MHz (20MHz Binary. hex. formats. 2K word acquisition 6Hz- 100kHz. Sine output <30yV- 5Vrms. - 2dB/ +4dB and 310K: 0-30V at 0-1A, 0-30V at ''4A & 4V -6V at 31/2A. octal, decimal, or V scales. Distn.<0.15% 15Hz- 150kHz. Mains/battery. 320K: 0-30V at 0-2A, 0-30V at IA & 4V -6V at 7A. memory. Non volatile ref. memory. FREE DELIVERY MAINLAND UK. VAT EXTRA. QUANTITY DISCOUNTS AVAILABLE. Maxon Street, Barnet, Herts., EN5 5SD, England LEVELL ELECTRONICS LTD. Telephone: 01 -440 8686 & 01 -449 5028 CIRCLE 55 FOR FURTHER DETAILS. ELECTRONICS 8 WIRELESS WORLD MAY 1986 9

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DISK DRIVE PSU. 240E as 5V 1.64 & IN I.DA Oui. S. W125mm(10ea

GENERATORS (P&P f21

4300 SERIES N.P. SWEEP OSCILLATOR 12611t 6910 ....._....[100 SWEETS KEYBOARD n LYNX MICRO(_ Push Otto Lamente ayaü0le. las to make. Ca...... 000LE (6o P&P 121 HEWELT7 PACKARD 6168. 184.2GH1 ....1350 MARCONI 02508 AM/FM 10KH,- 5101Mi1 ...(1.200 MARCONI 111556811 AM/FM IDMHt470MH, 050 AVO TRANSISTUR TESTER 71169 Handheld 0011000 for nstu BETTRE MARCONI 7F995Á15 1.5 220MHz. Rum/ Oewarion 5250 Testep Compete with Baneres. leads & Insleuctems IP &P 531 ADVANCE YOU 5663E 061111M 4.230M16 (100 NOW ONLY (12 ADVANCE type SG626 AM 155116 22051, (45 MARCONI TFI44H41OKHL 72MHt.. 555 NEW EQUIPMENT WAYETEK FUNCTION GEN 162 0001Hz 30MHz 5500 STANDARD H.P. TEST OSCILLATOR 851A 15510MH2 (100 HAMEG OSCILLOSCOPE 605, Dual Trace 60MHz RADIOMETER SMG40 STEREO GEN...... 5300 Delay Sweep, LEADER FM STEREO GEN 150231...... (125 Component Tester E515 FARRELL MoOder Pulse ce,e,aer sraum 1x :loAix,...... lso HAMEG OSCILLOSCOPE 203.5 Duel Trace 20MHz Component Tester E27B N.P. DISTORTION ANALYSER 331A .._ ...... _..._....ROO N.P. 4342'0' Meter _....__ ...... (1.250 All Other Modela babble. MARCONI 'LE Meta TFI245 with TFI246 or 711247 ...... _...... _(500 H.P POWER METER 431C with Thermsto Mount IIIMIly.10GHz of BLACK STAR COUNTER TIMERS (P &P E51 _ ...._LISO APOLLO 10 100MHz. RBtIDIPeriodITime Interval etc MIMARCONI RF _.4050 - MARCONI VALVE VOITMETRA Tf26G ION, -IOMx: 1mV 3GV FSD[10 E219 INSITO MARCONI UNIVERSAL BRIDGE TF27 01 ...... _...... _ n APOLLO 100 - 100MHz (As above - with more funs MARCONI UNIVERSAL BRIpDGE TF27G. Battey OpunM...... _..._..1255 Pons; E285 VO UNIVERSAL MEASURING BRIDGEpp, 1.....- ...... -(50 BLACK STAR FREQUENCY COUNTERS (P&P E4) H.P. VECTOR VOLTMETER 84S0Á.._ ...... 1950 Meteor 100 - 100MHz E99 H.P. BROADBAND SAMPLING VOLTMETER 34116Á I0KIH.1.26Hz...... £500 Meteor 600 600MHz St MARCONI AF SIGNAL SOURCE TF2000 20HZ- 20KNt.._...... (200 - ti M.P. RF MIILIVOLTMETER 4IIp 50171(Hx[ 500MNZ ...... _...... _...... _[a0 Meteor 1000 - 1GHz E17$ LEVELL TRANSISTOR AC MICROVOLTMETER TM3B U5 BLACK STAR JUPITOR 500 FUNCTION GENERATOR KFITHUET ELECTROMETER typa 610 with Adapta 6105. (500 P E4_E110 SOLARTRON TRUE RMS VOLTMETER VMI484.. ,...... _ ...... MO SinelSquarelTriangle 0.1Hz - 500KHz. &P N.P. TRUE EMS VOLTMETER 3400A 10HZ 10MHz ...... (400 FEEDBACK ELECTRONIC WATTMETER EW6O4 O6201(Hx ...... LITS HUNG CHANG OMM 6010. 31 digit. Hard held 28 R&S MICROWAVE POWER METER 111424131311 04042 ...... (150 M.P. OMM 3470 SYSTEM ranges including 10 Amp ACID[. FARNELL FUNCTION GENERATOR F03 ...... _(TOO Complete with batteries & leads. P &P E4 E33.50 FEEDBACK VARIABLE PHASE OSCILLATOR VP0230 116.1001011...... C75 H.P. WIDE RANGE OSCILLATOR 20000 5Ht600KH ,_...... _CIAO OSCILLOSCOPES PROBES. Switched Xl, X10 P&P E2 E11 RACAL 32MHS UNIVERSAL COUNTER TIMER type 836...... ISO tech WO mxnl THIS IS A VERY SMALL SAMPLE OF STOCK, SAE or Telephone for LISTS. Please check availabilIty COMPUTER INSTRUMENTATION before ordering. Carriage all units E12. VAT to be added BARRLE PLOTTER - 38 loA WIDTH, Twin Pen....._._...._...___. (SG to total on Goods and Carriage.

STEWART OF READING Telephone: 0734 68041 110 WYKEHAM ROAD, READING, BERKS RG61 PL Callers welcome 9a.m. to 5.30p.m. MON -FRI. (UNTIL 8p.m. THURSI CIRCLE 50 FOR FURTHER DETAILS. CROSSWARE SOFTWARE DEVELOPMENT TOOLS FOR THE BBC MICROCOMPUTER A range of small steel enclosures enabling smaller installations to be completed CROSS ASSEMBLERS with ease. FULLY SUPPORTED QUALITY SOFTWARE Optional plain or glazed door with locking variations are available ex stock. As exhibited at MDS '86 Split design permits mounting within the Is it really possible to use the BBC micro and a single disc drive door as well as on the standard backplate. to assemble more than 4 megabytes of source code? Yes... if you're using one of our XR- series cross -assemblers 4300 Series is strong and gives good and making full use of local labels. protection against dust and liquids. But there is more to our software than that. So much more in fact that we will send you a free comprehensive data sheet to Attractive epoxy powder paint finish. tell you about it. Since 1984, industry has been using our cross- assemblers to develop applications ranging from defence systems to software Please send me details of how Sarel's 4300 series for the Amstrad; and education has found them an ideal aid for of small steel enclosures set the standard. teaching microprocessor system development. Name They are available immediately from stock and are supplied on 16k ROMs, each with one or more utilities discs They're Econet Company compatible and run on any model B or B+ fitted with Basic II and a 1.20 or later operating system. Position Order Code Target Processors Price Address 6801XR 6800,6801,6802,6301...6301X £48.00 Telephone 6805XR 6805,146805,6305 £48.00 6809XR 6809 family £48.00 Sarei Limited 8085XR 8085,8080A £48.00 Z8OXR Z80, HD64180 £48.00 Cosgrove Way, Luton, Beds. 68000XR 68000,68008 £56.00 Telephone: Luton 20121 65CO2XR 65CO2, 65SCO2, 6502 £38.00

Further information from: (prices exclude VAT) CROSSWARE PRODUCTS The Lawns, Melboum, Royston, Harts SG8 6BÁ Telephone: 0763 61539 CIRCLE 33 FOR FURTHER DETAILS. CIRCLE 16 FOR FURTHER DETAILS. 10 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com DESIGN, DEVELOPMENT AND MANUFACTURE ((004018ins. OF RF COMMUNICATIONS EQUIPMENT RESEARCH COMMUNICATIONS LTD. UNIT 3, DANE JOHN WORKS, GORDON ROAD, CANTERBURY, KENT CT1 3PP TELEPHONE: CANTERBURY (0227) 456489

FREQUENCY CONVERTERS

In the range 30.1000 MHz. TYPE 9118 Receiving. 15V. + supply TYPE 9159 £65 +£2 p &p 'TYPE 9152 TYPE 9113 Tranmsmitting. With phase lock- TELEVISION LINEAR POWER AMPLIFIERS Tuned to your specified channels in bands IV or ed loop frequency control £295 + £5 p &p V. (or 400 -900 MHz). TYPE 9261 150mV. input, 20mW output £180 + £12 p &p TYPE 9252 20mW. input, 1 watt output £210 + £12 p &p TYPE 9259 1 watt input, 8 watts output £240 + £12 p &p

TYPE 9051 TYPE 9046

TMOS WIDEBAND LINEAR POWER AMPLIFIERS 4/10/20 watts RF output. Without tuning. Power gain 13dB. (X 20). 24V + supply. GASFET RF PREAMPLIFIERS. Aligned to your specified frequency in the range 30 -1000 MHz. TYPE 9046 100KHz.- 100MHz. 4 watts £89.50 + £3.50 p &p Masthead or local use. TYPE 9051 15MHz.- 200MHz. 4 watts £89.50 + £3.50 p&p TYPE 9006 N.F.0.6dB. Gain 10 -40dB. variable. In the range 30 -250 MHz £65 + £2 p&p TYPE 9171 15MHz.- 200MHz. 10 watts £140 + £20 p&p TYPE 9006FM As above. Band II 88 -108 MHz £65 + £2 p&p TYPE 9172 As above with integral mains power supply unit £210 + £30 p&p p&p TYPE 9002 Two stage Gasfet preamplifier. N.F. 0.7 dB. Gain 25 dB. adjustable. High O filter. Tun- TYPE 9174 15MHz- 200MHz. 20 watts £255 + £20 integral mains supply £325 + £30 p &p ed to your specified channels In bands IV or V £85 + £2 p &p TYPE 9175 As above with power TYPE 9004 UHF two stage Gasfet preamplifier. N.í.0.7 dB. Gain 25 dB. adjustable. High 0 filter. Aligned to your specified frequency in the range 250 -700 MHz £85 + £2 p &p TYPE 9035 Mains power supply for above units £24.50 + £3 p&p TYPE 9010 Masthead weatherproof unit for above amplifiers £9.50 + £2 p &p

TYPE 9155 TYPE 9157 TMOS RF LINEAR POWER AMPLIFIERS. Tuned to your specified frequency in the range TYPE 8034 PHASE LOCKED SIGNAL SOURCE using low frequency reference crystal. 10- 250MHz. £190 + £12 p &p Specify output in the range 1-600 MHz. Output 10 mW. + 10 dBm £99.50 + £2 p &p TYPE 9105 10mW input, 1 watt output. 24V. + supply £270 + £15 p &p TYPE 9182 FM EXCITER ± 75 KHz. deviation. Output 10mW £205 + £5 p &p TYPE 9155 1 watt Input, 30 watts output. 24V. + supply £390 + £30 p &p TYPE 9086 FM TRANSMITTER 88-108 MHz. 50 watts RF output. 24V. + supply. Complete TYPE 9156 As above with Integral mains power supply unit £195 + £15 p &p modular system £680 + £30 p &p TYPE 9106 100mW Input, 10 watts output. 24V. + supply £370 + £20 p &p TYPE 9087 As above with Integral mains power supply unit £800 + £40 p &p TYPE 9158 5 watts input, 80 watts output. 24V. + supply TYPE 9157 As above with integral mains power supply unit £450 + £30 p &p PLEASE ADD 15% V.A.T. ON TOTAL CIRCLE 7 FOR FURTHER DETAILS. PRINTERS - MONITORS - TERMINALS - PERIPHERALS Burroughs MT710: Intelligent Green 12" VDU with 3 micros and 64K store. RS232. Programmable. Only UNIVERSAL DEVELOPMENT SYSTEM £ 149 new + £15 P &P. (for BBC Microcomputer model B or B +) 12" Open chassis Video Monitor: by Hitachi standard composite Video and 12v input. Green screen, wide If you're not really serious about Microprocessor development you can probably get bandwidth. £40.00 + £7.00P. away with using a 'toy" assembler - like the one for the BBC that uses BASIC. But for people who program for a living, meeting project deadlines and documentation Cased Video Monitors : 12" or 15" Green Screens fast, precision tools, not video & mains + £7.00 standards is no game. A professionol programmer needs standard composite £60.00 something that fell out of a Christmas cracker. P &P. And there is no more powerful and professional Assembler available, within fifty times the Centronics 306 Line Printers: Professional fast (1 20 cps), price, thon the UNIVERSAL DEVELOPMENT SYSTEM META Assembler. Parallel i ONLY £99 superb quality 80 column printer. /f. Not only does this one Assembler, supplied on two 16K ROMs and two discs, allow you to + £15.00 P +P. write code for almost all the major Microprocessors (using the appropriate standard in (A2, D5.1) etc in 68000; see table Texas Silent 700 Printers: Whisper quiet 80 col matrix codes, eg LD (HL), A etc Z80, MOVE.B DO, label printer with RS232 interface. ONLY £99.00 + £7.00 for full list) but it also: P &P. Includes a fully integrated Editor, with features such as search, search /replace, block copy /delete and a list of other features specially Diablo 630 Daisywheel printer: OEM i/f NEW £599 + £15 P &P. designed with the Assembly programmer in mind Calcomp 565 Drum Plotter: OEF £450 + £10 P +P. is able to Assemble several MegaBytes of source and produce Many more bargains. Phone for your requirements. WE ALSO BUY. unlimited object code can sustain over 16,000 average 32 -bit labels simultaneously BECKENHAM PERIPHERALS LTD is able to pass string or expression parameters to macros or modules welcome SAE for LIST Callers arithmetic assembly -time cruncher by appointment 01.466 5582 and enquiries includes o full boolean and 34 Rodway Road, Bromley (brackets to eight levels!) Kent BRt 3JL includes over fifty directives to facilitate nestable IN /ELSE /ENDIF conditionals, every common type of data equate (FCB /EQUB /DATA/ CIRCLE 38 FOR FURTHER DETAILS. DC.B etc) Can send object code during Assembly to RS423, disc files, EPROM Emulator(s) etc, and in Intel Hex, S- record, storight binary etc formats. There are, in fact, over 30 different options. U.S. supplier of RF POWER DEVICES. RF The META Assembler has been on sale for over a year; we've sold hundreds into Prices LOWER than current domestic prices. Universities, Polytechnics and to both large and small industry. Query us for immediate needs. Low-cost and high performance is assured in all Crash Barrier products. The complete POWER META Assembler package, for example, costs just £ 185, yet it assembles for all the listed processors. A quality source for a complete range of RF POWER devices - From 2- /AMATEUR 27 -50 Please telephone for your free 8 -page brochure on the whole UNIVERSAL 30MHz, SSB 12.5V 7 28V transistors -14 -30 MHz CB DEVELOPMENT SYSTEM (which includes the PORTAL EPROM Emulators, the MHz, low band FM - 66 - 88MHz, mid band FM - 66 - 88MHz, mid band Universal Logic Analyser and the Multiple EPROM Programmer). HI FM -156 -162MHz VHF MARINE RADIO FM -130 - 175MHz -BAND Isn't it time you stopped toying with your ideas and got properly tooled up? VHF FM - 108- 152MHz VHF AIRCRAFT AM - 225 40MHZ UHF 28V - 407 - 512 UHF CATV/MATV CLASS A linear transistors -A SMALL All 6800 series, incl. all 6300, 6809 and 68HC11; 68000; 8048 series; RUPI -44; 8051 indication of types are listed below. SEND FOR OUR FREE BROCHURE series; 8080, 8085; 8400; ALL 6500 series incl. ALL CMOS, 65C812 and 65C816; AND /OR CONTACT FOR IMMEDIATE QUOTES. HD64180, Z80; Z8 and more! MRF450IMRF453'MRF646 BLY88A BLY901BLY93A CRASH BARRIER ..2N3553 .2N4933 .2N5109 .2N3375 .2N5016 ...689 .2N4128 .2N5070 .2N5591 .2N6080 .2N4427 .2N5090 FREEPOST .2N5634 .2N6083 .2N4431 .2N5102 .2N5918 .2N6084 FLITWICK BEDFORD M TIC Semiconductor inc. (0525) 717148 MK45 1 YP 18 WEST 21st STREET NEW YORK, N.Y. 10010 U.S.A. TICS UR . TEL: (212) - 675 6722 TELEX: 284564 CIRCLE 9 FOR FURTHER DETAILS. CIRCLE 10 FOR FURTHER DETAILS ELECTRONICS & WIRELESS WORLD MAY 1986 11

www.americanradiohistory.com PHONE P. M. COMPONENTS LTD TELEX 0474 60521 SELECTRON HOUSE, SPRINGHEAD ENTERPRISE PARK 966371 4 LINES SPRINGHEAD RD, GRAVESEND, KENT DA11 8HD TOS -PM

TDA2523 2.95 INTEGRATED CIRCUITS STK025 11.95 T8A540 1.25 TDA2524 1.95 CATHODE RAY TUBES Please add f3 additional carriage per tube. STK043 15.50 TBA540Q 1.35 TDA2530 1.95 AN124 2.50 MC 1327 1.70 STK078 11.95 TBA550Q 1.95 TDA2532 1.95 CME822W 19.00 087.36 55.00 M38.121LA 85.00 AN2140 2.50 MCI 327Q 0.95 STK415 7.95 TBA560C 1.45 TDA2540 1.95 CME822GH 25.00 DG7.32 45.00 M38-122GW 65.00 TBA560C AN240P 2.80 MC1349P 1,20 STK433 6.95 1.45 TDA2451 2.15 CME1428GH 45.00 DGI 3.2 45.00 M38-140LA 86.00 AN812 2.15 MC1351P 1.50 STK435 7.95 TBA460C0 1.45 TDA2560 2.16 CME1428W 39.00 DH3-91 56.00 M38-142LA 85.00 AN7140 3.50 MC1357 2.35 STK437 7.95 TBA570 1.00 TDA2571 A 4.50 CME1523W 39.00 DH7.91 45.00 M38-341831 86.00 AN7145 3F0 MC1358 1.58 STK439 7.95 TBA651R 2.50 TDA2581 2.96 CME1431GH 39.00 DP7.5 36.00 M38-344P39 65.00 TBA720A AN7150 2.95 MC1495 3.00 STK461 11.50 2.46 TDA2593 2.95 CME1431W 39.00 DP7.8 36.00 M40-120W 59.00 BA521 3.35 MC1496 1.25 TA7061AP 3.95 TBA750Q 2.85 TDA2600 6.50 CME202GH 46.00 138 13.78 35.00 M43-12LG/01 85.00 CA1352E 1.75 MC145106P7 TA7108P 1.50 TBA800 0.89 TDA2610 2.50 CME2024W 46.00 M44-120LC 65.00 CA3086 0.48 7.95 TA7120P 1.85 TBA810AS 1.85 TDA2611A 1.95 CME2325W 46.00 F18-101GM 75.00 M44-120GR 86.00 CA3123E 1.50 MC1723 0.50 TA7130P 1.50 TBA81OP 1.85 TDA2640 3.50 CME3128W 46.00 F16-101LD 75.00 M50.120GH 85.00 HA1366W 3.50 MC3357 2.75 TA7176AP 2.95 TBA820M 0.75 TDA2880A 2.75 CME3132GH 45.00 F21-130GR 76.00 M50-120GR 66.00 HAI 377 3.50 ML2318 1.75 TA7203 2.96 TBA820Q 1.45 TDA2890 2.45 CME3165W 45.00 F21-130LC 76.00 M50-120GV 66.00 HA1156W 1.50 ML2329 TA7204P 2.15 TBA890 2.50 TDA3310 CRE1400 26.00 F31-10GM 75.00 2.50 2.95 I M50-120LC 65.00 HA1339A 2.96 MSM5807 8.75 TA7205AP 1.15 TBA920 1.65 TDA3560 5.50 CV429 89.00 F31-10GR 76.00 M81-120W 75.00 HA1398 2.75 PLLO2A 5.75 TA7222AP 1.80 TBA950/2X2.36 UPC566H 2.95 CV1450 35.00 F31-10LC 76.00 S6A8 45.00 HA1551 2.95 SAA500A 3.50 TA7227P 4.25 TBA990 1.49 UPC575C2 2.75 CV1526 19.00 F31-10LO 76.00 SE4/D/P7 46.00 LA1230 1.95 SAA1025 7.26 TA7310P 1.80 TCA270 1.50 UPC1025H 1.95 CV2186 15.00 F31-12LD 76.00 SE42BP31AL 55.00 LA4031P 1.95 $A$560$ 1.75 TA7313AP 2.96 TCA270SQ 1.80 UPC1028H 1.96 CV2191 19.00 F31-13GR 75.00 5E426P31 55.00 TCA650 LA4102 2.95 SAS570S 1.75 TA7321P 2.25 3.60 UPC1032H 1.50 CV2183 15.00 F31.13LD 76.00 SE5FP31 56.00 LA4140 2.95 SAS580 2.85 TA7609P 3.95 TCA94O 1.65 UPC11565 2.75 CV6119 86.00 F31-13LG 75.00 7937 55.00 LA4400 4.15 SL1310 1.80 TA7811AP 2.96 TDA440 2.20 UPC1158H 0.75 CV6320 85.00 F41-123LC 185.00 T948N 56.00 LA4420 1.95 SL1327 1.10 TAA310A 2.50 TDA1001 2.95 UPC 1157C2 CVX389 55.00 F41-141LG 185.00 194811 55.00 LA4422 2.50 SL13270 1.10 TAA320A 1.95 TDA1002A 2.95 1.95 D9-110GH 39.50 F41-142LC 186.00 V4150LC 55.00 LA4430 2.50 SN76003N 3.96 TAA350A 1.95 TDA1006A 2.50 UPC1181H 1.25 D10-210GH 46.00 V5004GR M7 120W 69.00 LA4461 3.95 S5780235 3.95 TAA570 1.95 T0A1035 2.50 UPC1182H 2.95 010-21008888 86.00 19.00 V5004LD 69.00 D10-230tH M14-100GM LC7120 3.25 SN760335 3,95 TAA861B 1.95 TDA1037 1.95 UPC1185H 3.95 36.00 45.00 V8001 85.00 LC7130 3.50 S5761105 0.89 TBA700 1.70 TDA1170 1.95 UPC1191V 1.50 D10-230GM 35.00 M14-100LC 45.00 V6007DP31 M17-151GVR 59.00 LC7131 5.50 S5781155 1.25 TBA120AS/B/C/ TDA1190 2,15 UPC1350C 2.95 D10-293GV/90 65.00 175.00 V8008GW 59.00 LM324N 0.45 SN76131N 1.30 SA/SB/T/U 1.00 TDA 12700 3.95 UPC1353C 2.45 D13-30GH 49.60 M17-151GR 175.00 V8034WA 59.00 LM380N8 1.50 SN7622613N TBA395 1.50 TDA1327 1.70 UPC1365C 3.96 D13-47GH/28 55.00 M19-100W 46.00 V6048CAL M19-103W 69.00 LM380N14 1.75 2.95 T8A396 0.75 TDA2002 1.95 UPC2002H 1.95 D13-61GU28 86.00 65.00 V6048J 49.00 LM383T 2.96 SN78227N 1.05 TBA440N 2.55 TDA2003 1.95 555 0.35 D13-5I GM/28 85.00 M23-11 OGH 66.00 V80848P31 M23-1111.13 66.00 LM3900N 3.50 SN76533N 1.85 TBA4800 1.25 TDA2004 2.95 558 0.60 1313-450H/01 56.00 55.00 V6084CLA 56.00 M51513L 2.30 SN76544 2.65 TBA510 2.60 TDA2005 2.95 723 0.60 D13-471GH/28 59.00 M23-112GM 55.00 M23-112GV V6069GH 56.00 M51516L 2.95 S5785705 1.00 TBA510Q 2.50 TDA2006 1.95 741 0.35 D13-800GM 69.00 55.00 V6070P31 86.00 M51621L 1.50 SN76650N 1.15 TBA520 1.10 TDA2020 2.95 747 0.50 D13-810GH 69.00 M23-112GW 55.00 V7030 59.00 M83712 2.00 SN76660N 0.80 TBA5200 1.10 TDA2030 2.80 748 0.35 D 13-511014 69.00 M23-112KA 55.00 V7031GH 59.00 MC1307P 1.00 STK014 7.95 TBA530 1.10 TDA2190 3.95 7805 0.85 1313-8110M 69.00 M24-120GM 59.00 V7031/87A 59.00 MC1310P 1.50 STK015 7.95 TBA5300 1.10 TOA2522 1.95 7808 0.80 D13-83006 69.00 M24-120LC 69.00 V7035A 49.00 7815 0.85 014-1600H 75.00 M24-120WAR 59.00 V7037GH M24-121GH 45.00 D14-160GM 76.00 56.00 V8004GR 85.00 D14-182GH/84 59.00 M28-12GH 55.00 80232 0.35 ' BFR90 1.50 HCA16334 0.90 V8008GH SEMICONDUCTORS M28-13LC 65.00 BD233 0.35 BFR91 1.75 RCA16335 0.80 014-172GR 56.00 49.00 V8010A 86.00 80234 0.35 BFT42 0.35 SKE5F 1.46 D14-172GV 56.00 M28-131.6 48.00 VCR139A 11.50 BD238 M28-13GR 0.49 BFT43 0.35 TIP29 0.40 D14-173GH 66.00 49.00 2881 13.50 80237 0.40 TIP29C 0.42 M28-131013 AAY12 0.25 BC178 0.15 BFW92 0.85 D14-173GM 53.00 56.00 3581 11.50 BD238 0.40 BFX29 0.30 TIP30C 0.43 M28-133GH AC125 0.20 BC182 0.10 D14-173GR 66.00 55.00 3DPI 11.50 AC126 0.46 8C18218 0.10 60242 0.85 BFX84 0.26 TIP31C 0.56 M31-101GH D14-18106/88 86.00 55.00 311/08M 55.00 AC127 0.20 BC183 0.10 BD248 0.75 BFX85 0.32 TIP32C 0.42 1314-181GJ 66.00 M31-182GR 55.00 BD376 0.30- TIP33C 0.95 3WPI 18.50 AC128 0.28 BC183L 0.09 0.32 8FX86 1314-181GM 53.00 M31-182GV 63.00 80410 0.85 BFX88 0.26 TIP348 0.96 4EPI 30.00 ACI 28K 0.32 BC184L8 0.09 014-181GM60 M31 184W 65.00 AC141 BC204 BD434 0.65 BFY50 0.21 TIP41A 0.45 59.00 5881 9.00 0.28 0.10 D14182GH 69.00 M31-184GH 85.00 AC141K B 50437 0.75 BFY51 0.21 TIP41C 0.46 5BHP1 0.34 C2078 0.13 M31-184P31 30.00 AC142K 0.46 BC208B 0.13 80438 0.75 BFV52 0.25 TIP42C 0.47 D14-200BE 89.00 65.00 5BHP1FF M31 185W 30.00 AC178 0.22 8C212 0.09 80520 0.66 BFV80 0.77' TIP47 0.55 D14-2000A/60 86.00 89.00 5BHP31 30.00 BLV48 TIPI 20 0.60 M31-190GH AC178K 0.31 BC212L 0.09 BD538 0.86 1.76 D14-200GM 76.00 55.00 5CPI 10.00 AC187 BD597 0.95 BRV39 0.45 TIP125 0.55 D 14-210GH M31-190GR 0.25 BC212LA 0.09 76.00 55.00 6E87/S 39.00 AC187K 0.28 BC213 0.09 BD589 0.45 BR100 0.26 TIP142 1.75 D14-270G11/60 M31-190LA 55.00 76.00 131381 13.60 AC188 0.26 BC213L 0.09 BD701 1.25 88110 0.49 TIPI 61 2.95 D14-310W 110.00 M31-191GV 66.00 BD702 1.25 BR103 0.55 TIP2955 0.85 135PA4 17.50 AC188K 0.37 8C214 0.09 D 14-320011/82 86.00 M31-220W 69.00 ACY17 1.15 BC214C 0.09 50707 0.90 BRC4443 1.15 T1P3055 0.56 M31-27067 17DWP4 25.00 BDX32 1.50 BT100A/020.86 T1591 0.20 D14-3400H/KM 46.00 85.00 32J/1085 AD142 0.79 BC214L 0.09 M31-271P31 69.00 AD143 0.82 8C2378 0.08 BF115 0.35 BT106 1.49 TV 108/2 1.50 D14-340KA 46.00 65.00 88D/898/89D/89L AD149 0.70 BC238 0.09 BF119 0.35 BT116 1.20 251308 1.35 018-1006H 86.00 M31-271GW 66.00 AD181 0.39 BC239 0.12 BF119 0.65 BT119 3.15 2N2219 0.28 D 16-1000H/86 69.00 M31-271W 65.00 16.00 AD182 0.39 BC251A 0.12 BF127 0.39 8T120 1.86 252222 0.29 018-10008/87 65.00 M36-141 W 75.00 1273 39.00 AD181/2 0.90 BC252A 0.16 SF154 0.20 8U105 1.95 252905 0.40 D18-100GH/79 89.00 M36-17OLG 75.00 1584 45.00 AF108 0.50 BC258 0.25 BF158 0.22 8U108 1.69 253053 0.40 D 18-1000887 55.00 M38-101 GH 86.00 1844 '80.00 AF114 1.95 BC258A 0.39 BF180 0.27 BU124 1.26 253054 0.69 D18-180GH 59.00 M38-103GR 65.00 9442E1 76.00 AF115 2.95 BC284 0.30 BF167 0.27 BU125 1.26 253055 0.62 M38 120W 95447GM BF173 0.22 BU128 1.80 293702 0.12 1321-100H 86.00 66.00 75.00 AF116 2.95 BC300 0.30 DG7-5 65.00 M38-120WA 65.00 954496M 75.00 AF117 2.95 BC301 0.30 BF177 0.38 BU204 1.55 2N3703 0.12 an no 1 AF121 0.80 BC303 0.28 BF178 0.26 011205 1.30 253704 0.12 0137.6 M38 12 0116 66.00 7709631 78.60 AF124 0.85 BC3078 0.09 BF179 0.34 BU208 1.39 253705 0.20 Vi AF125 0.35 BC327 0.10 BF180 0.29 BU208A 1.52 253706 0.12 AF126 0.32 BC328 0.10 BF181 0.29 B020813 1.85 2M3708 0.12 AF127 0.85 8C337' 0.10 BF182 0.29 503278 1.20 253733 9.50 NEW VIDEO SPARES & HEADS AF139 0.40 BC338 0.09 BF183 0.29 BU407 1.24 253773 2.78 AF150 0.80 BC347A 0.13 BF184 0.28 BU500 2.26 2N3792 1.35 BF185 0.28 BU508A 1.95 254427 1.96 VIDEO BELT KITS AF178 1.96 BC461 0.35 Sanyo VTC AF239 0.42 8C478 0.20 BF194 0.11 BU526 1.90 254444 1.15 Akai VS9300/8500 / 5600 3.75 BF195 130800 2.26 255294 0.42 VIDEO HEADS Sanuyo VTC 9300 3.76 AFZ12 3.75 BC527 0.20 0.11 for 9800 E3.75 ASY27 0.85 8C547 0.10 BF198 0.11 BUY698 1.70 255296 0.48 3HSS Suitable Most JVC Ferguson 3716 4.50 Sanyo VTC 9300P 3 90 and Ferguson modals E29.50 AU108 4.60 BC548 0.10 BF197 0.11 MJ3000 1.98 2N5298 0.80 JVCH HR 3330/3600 Sharp VC 6300 3.75 3808(H) Suitable for Hitachi 4.50 AU107 3.60 8C549A 0.10 BF198 0.18 MJE340 0.40 255485 0.46 JVC HR 3360/3660... 4.50 Sham VC 7300 3.75 AU110 3,50 BC550 0.14 BF199 0.14 MJE520 0.48 255496 0.95 VT5000, VT8000, 1178000, Panasonic NV 300 Sharp VC 8300 3.75 BF200 MPSA13 0.29 2SA715 ... 4.00 AU113 4.50 8C557 0.08 0.40 0.60' VT8500. VT7000 E33.95 Panasonic NV Sharp VC 9300 3.75 BF241 0.15 MPSA92 0.30 2SC495 0.80 20008. 3.75 BC107A 0.11 13C5578 0.80 4HSS Suitable for most Panasonic 30008 3.75 Sony SL 30008 3.75 BC107B 0.11 BC558 0.10 BF245 0.30 MRF237 4.96 2SC496 0.80 National Panasonic Models Panasonic Sony SL 8000 /8080 460 8C108 0.10 BCY33A 1.80 BF257 0.28 MRF45OA 13.95 2SC1096 0.80 NV7000... 3.50 E32.95 Panasonic NV 86008/ Sony SL C7 /J7 4.00 BC 1013A 0.11 80115 0.30 BF258 0.28 MRF453 17.60 2SC1106 2.50 4HSSIUINI Suitable for BF259 0.28 MRF454 26.60 2SC1172Y 2.20 86108/V011 . 3.75 Toshiba V5470 4.50 BC1088 0.12 BD124P 0.69 Panasonic Models 8C109 0.10 50131 0.42 BF271 0.26 MRF455 17.50 2001173 1.15 370 and 8C109B 0.12 8D132 0.42 BF273 0.18 MRF475 2.95 2SC1306 1.40 380 E33.95 SANYO ORIGINAL VIDEO PARTS eC109C 0.12 80133 0.40 BF338 0.34 MRF477 10.00 2SC1307 1.75 8C114 0,11 BD135 0.30 BF337 0.29 MRF838 13.96 25C1384 0.60 BETAMIX VIDEO HEADS SANYO ORIGINAL BF338 0.32 OC16W 2.60 25C1449 0.80 PS3511 Pin) Suitable for Sony BC116A 0.15 B0136 0.30 PART NUMBER MODEL DESCRIPTION BC717 0.19 80137 0.32 BF355 0.37 , OC23 1.50 2SC1678 1.25 and Toshiba 5000 Serbs and 4-529- 1080013 VTC5150 Reel Motor 3.6W BC119 0.24 80138 0.30 BF382 0.38 0C28 1,50 2SC1909 1.25 NEC PV2400 E39.50 9.95 4-5277 -23501 VARIOUS Motor Asey. 9.75 BC125 0.25 80139 0.32 BF383 0.66 0C29 2.25 2SC1945 2.85 RSV -3-B Suitable for Sony BF371 0.25 0C32 2.26 2SC1954 0.95 4-527V -51000 5150 Capeton Motor BC139 0.20 80140 0.30 SL8000 518080 SLD7ME 29.95 50144 BF394 0.19 0C42 0.76 25C1957 0.80 143 -0- 490400900 FVHP615 Geer Idler Amy. . BC140 0.31 1.10 E39.50 5.95 BC141 0.25 B 150C 0.29 BF422 0.32 0C44 0.76 2SC1989 1.95 143-2-4571.05900 VTC9455 Stopper Reel Base 0.55 BC142 0.21 BD159 0.85 BF457 0.32 OC45 0.55 2SC2028 1.15 DSR -10 -R Suitable for 143 -0-5457-01701 Pinch Sony VARIOUS Roller Assy. 8.95 BC143 0.24 1313180 1.60 BF458 0.36 OC70 0.45 2SC2029 1.95 SLC5 SLCB SLC7 E39.50 143 -0-5457-01700 VARIOUS Pinch Roller Assy. 1.95 2SC2078 1.45 Sanyo Head BC147A 0.12 BD186 0.55 BF469 0.36 0071 0.66 for 143-0-551T- VTC9300 Idler Assy. BF467 0.88 0072 0.85 2SC2091 0.86 0.95 1 BC1478 0.12 80179 0.72 VTC9300/9500 E41.50 143-0-6617 -03800 VARIOUS Loading Roller BC148A 0.09 80182 0.70 8F494 0.46 0075 0.95 2SC2098 2.95 Sanyo Head for VTC 0.95 143-0.6627 -01201 VTC5150 Rae! BC1488 0.09 80183 0.70 BF495 0.46 0081 0.50 2SC2168 1.95 5300/5000 E41.50 Drive Pulley 8.50 BC149 0.09 BD201 0.83 BF595 0.23 0C171 3.60 2SC2314 0.80 143-0-9974-00100 FVHP615 Mod Kit IC BA6304A 1.95 BC157 0.12 50202 0.65 BF597 0.26 R200813 1.46 2SC2371 0.36 BC158 0.09 80203 0.78 BFR39 0.23 R20108 1.46 2S0234 0.60 Video Head Cleaning Tape (VHS automatic wet /dry8.5 VIDEO ALIGNMENT TAPES BC159 0.09 BD204 0.70 BFR40 0.23 R2322 0.58 35211 2.95 Video Head Aerosol Cleaner. 0.8 BC174 0.09 80222 0.48 BFR81 0.25 R2323 0.88 3SK88 0.95 5.2P Colour Bars 30 min. 49.60 R2540 2.48 351038 0.96 Video Copying Lead and Connector Kit 11r 7.9 BC174A 0.09 BD223 0.69 BFR88 0.30 S-3P Stehstegs 30 min. 49.50 BC177 0.16 80225 0.48

LINE OUTPUT TRANSFORMERS E H T MULTIPLIERS VARICAP TUNERS I PUSH BUTTON UNITS BY210-S000.33 N4001 0.04 DIODES BY223 0.90 N4003 0.04 DECCA 100 7.95 AA119 O.a3 BY298-4000.22 (14004 0.06 DECCA 1700 MONO 9.96 ITT CVC20 8.35 ELC1043/05MUUARD 8.86 DECCA, ITT. CVC20 SWAY 7.96 BA116 0.13 B Y298-8000.22 N4005 0.05 DECCA 1730 8.95 ITT CVC30 8.35 ELC1043/08 MULLARD 8.85 ITT CVCS 7 -WAY 10.19 BA146 0.16 BYX10 0.20 N4007 0.06 DECCA 2230 8.25 PHILIPS G8 650 6.96 U321 8.25 PHIUPS 08155015-WAY 14.49 BA148 0.17 BYX36-160R N4148 0.02 GEC 2040 8.95 RANK 720A 6.91 U322 7.67 134164 0.06 0.26 N4448 0.10 GRUNDIG 1500 15.45 THORN3000 /3500 U324 11.00 00MAOUICK:BLOW FUSES BA168 0.16 BYX38-600R N5401 0.12 GRUNDIG 510-6010, 2222, 5011.5011 THORN 8500 8.00 BA/57 0.30 0.60 N5402 0.14 13.45 THORN 9000 8.00 O0MA Bp each BAX13 0.04 BXY65-8000.30 N5403 0.12 ITT CVC20 8.20 UNIVERSALTRIPLER 5.45 THERMISTORS (200MA-5AMP 5p each BYX71-8001.10 N5406 0.13 BÁX16 0.06 ITT CVC30 8.25 VA1040 0.23 gZY135C30 0.36 N6407 0.16 13131066 0.30 PHILIPS G6 8.50 REPLACEMENT VA1068S 0.23 C54B 4.60 N5408 0.16 20MM ANTI SURGE FUSES 87161 0.79 PHILIPS 69 8.99 VA1104 0.70 13Y126 0.10 CS10B 8.46 ITT44 0.04 PHILIPS 611 13.99 ECTROLYTIC CAPACITOR VA8850 0.46 100MA -800MÁ 16p each 57127 0.11 0447 0.09 71923 0.15 PVE 725 10.95 VA1097 0.25 1A - 6AMP 12p each BY133 0.16 0690 0.06 ITT2002 0.10 RBM T20A 12.40 DECCA 301400- 400 /38071 2.95 BY184 0.46 0A91 0.06 TANDBERGE90 11.15 DECCA 80/1001400/305V) 2.98 0495 0.06 BY77S 1.20 ZENER TELEFUNKEN711A 11.15 DECCA 1700 SPARE & AIDS BY179 0.63 04202 0.10 400 DIODES THORN 1590 9.50 1200 -200- -350V) 3.66 B7182 0.66 IN21DR 5.00 GEC HEAT PUSH PULL MAINS SWITCH THORN 8000 23.50 21101800/300V) 2.25 SINK COMPOUND 1.00 BY184 0.35 1N2313 5.00 BZX61 ITT RANK. THORN Serias THORN 9000 9.95 CVC201200/400V1 1.80 FREEZE IT 0.96 (DECCA, GFC. . IN23C 5.00 BV186 0.40 0.15 PHIIPS G 1600 /300V1 2.25 SOLDA MOP 0.64 ETC.( 1.02 IN23ER 5.00 THORN 9800 22.40 BY20b 0.14 BZY88Series PHILIPS 69(2200 o 635) 1.19 SWITCH CLEANER 0.86 PVE IF GAIN MODULE 1 6.99 BY200--8000.33' IN23WE 5.00' 0.10 PHILIPS G11 1470/250VI 2.35 WD40 1.75 ANODE CAP 1276V) 10.59

12 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com PHONE P. M. COMPONENTS LTD TELEX 0474 60521 SELECTRON HOUSE, SPRINGHEAD ENTERPRISE PARK 966371 4 LINES SPRINGHEAD RD, GRAVESEND, KENT DA11 8HD TOS -PM 1E3

M8223 4.50 0S75/40 3.00 UF80 1.75 3A/141K 11.50 6BG6G 3.00 658G 3.00 12567 2.50 872A 27.50 A SELECTION FROM OUR M8224 2.00 QS92/10 5.00 UF85 1.20 3A/147J 7.50 6BH6 1.95 6508 5.50 12S07GT 1.50 873 60.00 884 5.50 M8225 3.96 Q595/10 4.86 UF89 2.60 3A/167M 10.00 6BH8 1.50 6KM8 2.50 1303 3.20 342 930 9.95 STOCK OF BRANDED VALVES ME1401 29.50 05108/45 4.00 UL44 3.50 3.95 613.16 1.20 8578 2.95 1307 3.20 QS150/15 6.95 UL85 0.86 3A3A 3.95 61354 4.00 BL1 2.50 1309 3.20 931A 13.95 EBF83 0.95 1.40 ME1402 29.50 A1714 24.50 EL504 QS150/30 1.15 JUS 3.50 344 1.10 60574 1.95 6L15 3.16 130E7 2.50 954 1.00 E8F85 0.96 EL509 5.25 ME1501 14.00 1.00 A8134 7.50 05150/45 7.00 UU7 8.00 3AL5 0.95 6BL6 195.00 BL19 3.95 13067 2.95 955 EBF89 0.70 EL519 8.96 MH4 3.50 958A 1.00 A1998 11.50 051200 3.95 UU8 9.00 3AT2 3.35 6BL8 1.15 618GC 2.95 13E1 145.00 EBF93 0.96 3.85 MHL6 4.00 1299A 0.60 A2087 11.50 EL802 QS1202 3.95 U041 3.50 3B2 3.00 6BM8 0.68 BL8GCIGEI 13EM7 3.50 A2134 14.95 6E81 2.50 EL821 8.60 ML4 4.50 1619 2.50 MS48 5.50 0S1203 4.16 U985 0.70 384 7.00 6BM8 155.00 4.50 16GY5 2.95 A2293 5.50 6131.21 2.00 EL822 12.95 051205 3.96 V235A/1K 387 4.50 6BN4 1.65 6LBGT 1.95 1457 1.95 1625 3.00 A2426 29.50 EC52 0.75 EMI 9.00 MU14 3.60 1626 3.00 MZ1.100126.00 051206 1.06 250.00 3824 10.00 BBNB 1.85 6L020 1.15 170E3 2.50 A2599 37.60 EC70 1.76 EM4 9.00 0.90 V238A/1K 3828 24.00 6097 4.50 8LF6 7.60 17DW4A 2.95 2050W 4.95 EC80 9.50 N37 12.50 051207 A2792 27.50 EM80 0.70 QS1208 0.90 295.00 3828 12.00 6BN8 3.95 BLJB 2.50 17EW8 0.95 2050 3.95 EC81 7.95 N78 9.85 A2900 11.60 EM81 0.70 OS1209 3.15 V240C/1K 3828 1.50 6005 0.75 6LQ8 4.95 17JZ8 4.50 2051 5.50 EC8B 1.00 0A2 0.85 A3042 24.00 EM84 1.86 1.50 225.00 3C4 1.00 6005 0.75 1307 2.60 1803 6.00 3534 4.00 EC88 1.00 OA2WA 2.50 051210 404A 10.95 A3283 24.00 EM85 3.95 1.50 3C23 19.00 BB07A 0.72 BN70T 2.60 19405 3.50 EC90 1.10 0A3 2.50 051211 V241C/iK 15.00 AC/HL/DD 4.00 EM87 2.50 Q81212 3.20 196.00 3C45 24.00 6BL7GTA 3.96 6P15 1.60 194U4GT 2.50 927 EC91 5.50 082 0.85 1927 25.00 AC/THI 4.00 EN32 15.00 051213 5.00 V339 3.50 3C86 1.50 6E195 0.70 6P25 4.00 1903 1700 EC92 1.95 1.60 OB2WA 2.50 4212E 250.00 ACT22 59.75 EN91 001215 2.10 V453 12.00 3C N34 2.50 6097 4.96 81728 4.00 19H5 33.50 EC93 1.50 EN92 4.60 0C2 2.50 4313C 4.00 A14221 39.00 QS1218 6.00 VL5631 10.95 3CS6 0.95 8BR8 2.15 6P28 2.00 1908 9.00 EC95 7.00 EY51 0.80 0C3 1.50 43280 9.00 AH238 39.00 QU37 9.50 VP4B 4.50 3CX3 2.50 68889 2.16 607 1.75 2QA2 10.50 EC97 1.10 EY81 2.36 OD3 1.70 5636 5.50 ALSO 9.00 0V03-12 5,75 VP133 2.00 3CY5 1.50 6BS7 5.50 60701 1.20 2001 0.70 EC8010 12.00 EY83 1.50 0M4 1.00 5642 9.50 ANI 14.00 QV05-25 1.75 VR75/30 3.00 308 4.50 6BW4 1.50 6R7G 3.15 20LF8 7.95 ECC32 3.50 6084 5.95 0M58 3.00 5651 2.50 ARP12 0.70 QV06-20 29.50 VR101 2.00 3D21A 29.50 6BW6 5.35 8544 1.50 20L1 0.95 ECC33 3.50 EY86/87 0.50 0M6 1.75 5654 1.95 ARP34 1.25 QVO8-100 V105/30 1.50 3E22 49.50 6BW7 1.50 854707 1.35 20P1 0.66 ECC35 3.50 6988 0.55 ORP43 2.50 5663 1.95 ARP35 2.00 145.00 VR150/30 1.15 3E39 39.50 6BW8 4.00 BSC7 1.50 20P3 0.60 ECC81 0.15 ORP50 3.95 3.25 EY91 5.50 0V2-2600 VT52 2.50 3EH7 1.95 68X6 0.48 85G7 1.35 20P4 1.95 5670 ECC8I Special EV500A 2.50 P61 2.50 5672 4.50 AZ11 4.50 46.00 VU29 4.60 3EJ7 1.96 613X7GT 3.50 6SH7 1.35 2005 1.15 Quality 1.95 EV802 0.70 P41 2.50 7.50 AZ31 2.50 Q93-125 65.00 VU39 1.50 3V4 2.50 6E26 2.50 65J7GT 1.20 21LU8 2.50 5678 ECC82 0.85 EX35 0.75 PABC80 0.60 5687 4.50 PC86 0.75 QY4-250 70.00 W21 4.50 3W4GT 2.50 68Z7 2.95 6557 1.35 2481 39.50 81.63 2.00 ECC82 Philipe E240 2.76 6C4 1.50 5692 3.50 PC88 0.75 014-400 7800 W77 5.00 485518 115.00 66K7GT 1.36 250069 2.95 BS450 67.00 1.95 E241 2.76 4.00 W729 1.00 4-65A 59.00 6C5 1.95 6SL7GT 0.85 25L001 1.75 5696 3.50 ECC83 0.86 6280 0.76 PC92 3.50 R10 BS810 55.00 818 12.00 W739 1.50 46874 9.50 6C8 2.50 85N7GT 1.35 25006 1.75 5704 3.50 ECC83 Brimer EZ81 0.75 PC97 1.10 5718 8.15 130814 55.00 1.60 X24 4.50 4-1254 72.50 6C8G 1.50 7507 1.35 29C1 19.60 1.36 6290 1.60 PC800 1.10 R17 5725 2.50 CIK 19.00 R18 2.60 X88/%66 4.96 4-2504 79.60 6C11 2.50 6557 1.96 29506 8.50 ECC83 Philips F606 2.96 PC900 1.25 5728 1.50 C3E 22.00 R19 2.60 X76M 1.95 4-400A 87.50 8U4GT 1.76 30C17 0.40 1.95 FW41800 2.95 PCC84 0.40 5727 1.95 C3JA 9.50 1.20 XC24 1.50 4-10004425.00 6C18 2.50 6UBWA 3.50 30C18 1.48 ECC83 Siemens PCC85 0.64 R20 C6A 9.00 R1189 55.00 XC26 0.60 4832 36.00 6CA4 4.96 BUB 1.15 3F6 0.95 5749 2.50 2.50 G5511K 9.00 PCC88 0.70 6750 1.85 C1108 65.00 RG1.125 4.95 XFW47 1.60 48074 1.76 8CA7 3.50 BU8A 1.50 30FLI 1.00 ECC83 G180/2M 8.95 PCC89 0.70 5751 2.95 C1134 32.00 RG XFW50 1.50 4E26 1.96 6CB5 3.95 6V6G 1.26 30FL2 1.35 Tungsrem 9.00 PCC 189 0-70 1-240A14.50 5763 CI 148A 115.00 0240/2D 3.50 4C27 25.00 6C136 1.95 6V6GT 1.50 30FL12 0.95 5.75 1.50 GC108 17.50 PCC805 0.70 RG3-250A XG1-2500 5814A C1149/1195.00 RG3-12504 60.00 4C28 25.00 BCDBGA 4.50 6VGG 1.00 30FL13 1.10 3.25 ECC84 0.50 GC 10D 17.50 PCC808 0.80 5823 9.60 C1150/1136.00 35.00 X02-8400 4C35 145.00 6CF6 1.60 BX2N 1.00 30FL14 1.25 ECC85 0.75 GC10/4B 17.50 PCE82 0.80 5829WÁ 6.50 C1534 32.00 RK2K25 62.50 135.00 4C86 1.95 B CG7 2.25 8%4 1.50 30L1 0.45 ECC86 2.75 GC10/4E 17.50 PCF80 0.85 5840 3.50 C3E 29.50 RK-20A 12.00 XG5-500 22.50 4CX1000A 6CH6 8.95 8X50T 1.00 30L15 0.80 ECC88 0.95 GC 12/48 17.50 PCF82 0180 5842 11.00 CCA 2.60 RLI8 1.50 X11-5V 1.50 425.00 6CL3 3.95 6X5GTY 1.00 30L17 0.60 ECC91 2.00 GD86W 6.00 PCF84 0.86 5847 10.95 CC3L 0.90 RPL16 12.00 XL828FT 7.50 4CX4000A 6CL8 3.25 6X88 2.26 30P4MR 1.00 ECC180 0.72 GDT120M 5.00 PCF86 5879 8.50 CK1008 3.60 RPY13 2.50 XNP12 2.50 1100.00 6C LBA 1.50 796 4.50 30P12 1.00 ECC189 1.96 GN4 8.00 1.20 5888 13.95 CV Nos Prices RPY43 2.50 XR1-1800A 4CX2508 49.00 6CM5 1.60 7A7 2.00 30P18 0.80 ECC801S 3.50 GN10 15.00 PCF87 0.40 5894 39.50 on request RPY82 2.60 49.50 4CX25013 B CM7 2.95 7AD7 1.75 30P19 1.00 ECC803S 4.96 GR10G 4.00 PCF200 1.80 5899 4.50 D3A 27.50 0133-250 16.00 XR1-3200A 4032 125.00 BCS6 0.75 786 3.50 30PL1 2.50 ECC804 0.80 GS10C 18.60 PCF201 1.80 1.75 D83 1.20 RR3-1250 35.00 79.50 EIMAC 59.50 6CW4 8.50 787 2.50 30PL13 0.80 5983 ECC2000 12.00 GS10H 12.00 PCF800 0.40 5965 2.25 DA41 22.60 RS613 45.00 %R1-84004 4CX2508M BCYS 1.00 7C5 3.50 30PL14 1.75 ECF80 1.15 GS12D 12.00 PCF801 1.35 6005 1.85 DA42 17.50 RS885 54.95 99.60 75.00 806 2.50 7C6 2.50 31JS6C 5.50 ECF82 1.16 GT IC 14.00 PCF802 0.80 6012 16.00 DA90 4.50 RS5888 52.15 9502 25.00 4CX250K 8DC8 2.35 7E7 2.50 33A/150M ECF88 1.70 GT IC SIS 13.00 PCF805 1.25 DA100 125.00 5.95 Y65 8.95 EIMAC 95.00 8DJ8 0.95 767 3.50 19.50 6021 3.65 ECF200 1.85 GTE175M 8.00 PCF806 1.00 S6F17 2.50 DAF91 0.70 28.96 76.00 4CX125C 6056 1.15 7AU7 1.50 3545 4.50 8057 ECF202 1.85 GTRI5OW 1.00 PCF808 1.25 S6F33 001100 DAF98 0.85 611612 38.00 YJ1060 285.00 EIMAC 125.00 6005 5.95 7J7 5.50 35L6GT 2.00 6058 3.95 ECF801 0.85 GU20 35.00 PCH200 1.50 3.75 DC70 1.75 A30/26 12.00 0L1020 29.00 4CX350A 96.00 60060 2.50 7Y4 2.60 3523 1.85 6059 DC90 1.20 ECF805 2.50 GU50 17.50 PCL82 0.85 6060 2.25 PCL83 2.60 5104/1K 10.00 YL1070 195.00 4CX350F 79.50 601134 1.50 888 2.50 38HE7 4.50 DCX-4-6000 ECF808 10.25 GXUI 13.50 8062 4.50 PCL84 5109/1K 16.00 9L1071 195.00 4XC1500B 60W4 2.16 8810 2.50 40506 5.50 25.00 ECH3 2.50 GXU3 24.00 0.75 8063 2.00 PCL85 0.80 S130 5.59 YL1290 85.00 398.50 8E5 3.95 8805 1.96 42 6.96 DET16 28.60 ECH4 3.00 GXU50S5 6064 3.25 PCL86 0.86 S130P 6.96 Z77 1.20 4GS7 2.25 6044 4.95 8F07 1.96 47 6.00 DET78 28.50 ECH35 3.60 14.50 6067 1.95 PCL800 0.80 SCl/800 5.00 Z302C 12.00 4GV7 2.25 8EA7 2.50 1002 1.25 5045 1.50 DET23 36.00 ECH42 1.00 00501 1.20 6072 4.20 PCL805 0.90 SC1/1100 6.00 Z359 9.00 4J52 75.00 6EA8 2.50 100E7 2.60 5005 0.95 DET24 38.00 ECH8I 0.85 00802 1.00 8080 8.50 PD500 3.50 SC1/1200 5.00 Z5058 15.00 4JCBA 2.95 BEBO 1.75 10EW7 2.95 50CD6G 1.16 DET25 22.00 ECH83 0.78 GZ30 1.00 8080WÁ 9.50 PD510 3.85 SC1/1300 6.00 Z520M 4.00 4X1509 35.00 6EM5 2.50 10F1 0.76 50E55 1.60 DEt29 32.00 ECH84 0.69 GZ31 1.00 6132 10.00 PE1-100 89.00 SC1/200 9.00 2521M 8.00 5A/1020 9.50 6EM7 2.50 10GK8 1.96 50JY6 2.95 DF91 0.70 ECH2000 1.50 GZ32 1.00 6136 2.50 PEN25 2.00 SP4I 5.00 27000 3.00 5A152M 9.00 6EU7 1.95 10P14 2.50 52KÚ 2.00 OF92 0.80 ECLBO 0.80 GZ33 4.60 15.00 61488 9.50 PEN4ODD 2.50 5P42 3.00 Z749 0.60 541635 10.00 8EU8 1.76 10P18 0.78 53CG DF96 0.85 ECL82 0.85 GZ34 2.16 5155 65.00 PEN45 3.00 SP48 4.95 Z759 19.85 54170K 8.25 6EV7 2.95 61SPT 4.50 DF97 1.00 ECL83 2.50 GZ37 4.60 6156 85.00 PEN45DD 3.00 SS501 35.00 Z8000 3.00 54-180M 9.00 8EW8 2.95 1OLD12 0.86 7581 3.50 DH83 1.20 ECL84 0.74 HAA91 1.00 6157 2.50 PNE46 2.00 ST11 1.50 Z803U 18.95 54-206K 10.00 8EW7 4.50 11E3 55.00 75C1 2.50 DH77 0.90 ECL85 0.88 HABC80 0.90 6158 3.20 PE06-4oN 42.00 STV280/40 241000 12.50 SAME 2.16 6F1 2.00 1296 3.96 80 4.50 OH79 0.56 ECL88 0.80 HBC90 0.75 6201 8.45 PFL200 0.95 11.96 2A1001 1.50 5498 1.20 6F5 4.96 12AD8 1.50 83 8.50 1311149 2.00 ECL805 0.89 HBC91 0.80 6205 8.95 PL2I 2.60 STV280/80 2A1002 1.50 5484 2.00 BF6 2.50 12AG8 1.50 84 3.00 DK91 0.90 EF37A 2.00 HF93 0.75 6211 2.50 PL38 0.95 19.95 ZM1005 8.00 5AU4 1.60 6F6G 2.00 12AL5 1.00 8541 6.50 DK92 1.20 EF39 1.10 HF94 1.50 58.110M 10.00 BF7 6.50 12478 0.95 8542 1.50 8287 4.50 EF40 4.50 5590 1.05 PL38 1.60 SU42 4.96 ZM1021 8.00 DL35 2.50 982.5/300 ZM1023 7.95 58-254M 14.50 BF12 1.50 12AT7 1.15 90AV 10.00 8350 3.50 DL83 1.00 EF41 3.50 HL2K 4.95 PL81 0.72 8380 4.50 PL8IA 0.72 85.00 ZM1041 14.00 58-255M 19.50 6F13 3.00 12AT7WA 2.50 90C1 2.70 DL70 2.50 EF42 3.50 HL23D0 4.00 13386 14.50 PL82 0.60 702.300 45.00 ZM1082 9.00 58258M 9.00 BF14 1.00 12AU6 1.50 90CG 13.50 DL73 1.50 EF50 2.50 HL41 3.60 6463 7.50 PL83 0.52 TB3-2000 ZM1084 10.00 513-257M 9.00 BF17 2.75 12417 0.85 90CV 12.50 01.92 0.96 EF65 4.95 HL4200 3.50 5B-258M 14.50 BF21 2.50 12AV8 1.96 91AG 9.00 6545 8.50 EF70 1.20 HL90 0.70 PL84 0.78 395.00 2M1177 9.00 DL93 1.10 55.00 5C22 126.00 6F23 0.60 12407 2.50 92AG 19.50 6550 10.95 EF71 1.60 HL92 1.50 PL88 1.00 TBL-2-300 ZM1202 DL94 2.50 275.00 ZM1263 4.00 5J1 80E2500.00 6F24 1.25 12AX4GT 1.00 92AV 12.60 6688 6.60 EF72 1.20 HL133xDD3.50 PL95 1.76 6870 11.50 DL98 2.50 TD1-100A26.00 ZM1612 3.00 5R4GB 3.50 6F25 1.25 129X7 0.85 95A1 6.50 DLSIO 13.50 EF73 1.00 HT2 4.00 PL302 1.00 6887 9.50 PL345 12.50 TD03-10F 36.00 584GY 3.50 BF28 1.25 124X7WA 2.50 DLS16 10.00 EF80 0.55 HY90 1.00 100E1 68838 9.95 PL500 1.10 T13 3-12 4.00 1A3 4.50 514 6.95 6F32 1.25 12407 3.95 10.00 DM70 1.96 EF83 3.95 HVR2 3.00 8973 5.95 PL504 1.15 TD04 6.60 lAC6 1.20 5U4G 2.60 BF33 17.00 124274 1.96 108C1 1.50 DM160 2.76 EF85 0.60 JP9-7A 60.00 BFGS 1.95 1284A 4.50 15082 6.95 7025 2.50 TP25 1.50 1 AE43.60 5U4GB 2.50 EF88 2.26 K3118 86.00 PL508 1.75 4.50 DY51 1.60 1B3GT 5V4G 1.25 6F07 2.95 112848 1.60 150C2 1.50 7027A EF88 Mullerd K86/3 45.00 PL509 4.85 TSP4 7.00 1.95 DY86/87 0.65 1711 1.60 1822 10.00 5V3GT 1.95 606G 5.50 128E6 1.96 150C4 2.15 7032 2.00 4.60 KTBC 7.00 PL519 4.95 7059 2.50 DY802 0.72 1824 14.95 5Z4GT 0.85 gGE5 3.95 1 129H74 2.50 155ÚG 25.00 EF89 1.50 KT33C 3.60 P18029 3.60 1721 45.00 1927 55.00 8/30L2 0.70 6GH8A 0.80 12BL8 1.76 185137 1.50 7167 3.95 EF91 1.96 KT38 2.00 PL820 2.96 E8OL 29.50 TT22 45.00 18354 29.50 6A/203K 9.00 6055 1.50 128079 2.75 211 33.50 7189 3.50 EF92 2.15 KT44 4.00 PL5557 29.50 7193 7.50 6811 12.00 1C1 2.60 847 4.95 13056 1.95 12C8 2.60 2744 15.00 EF93 0.96 KT46 4.00 PY32 0.60 TT100 57.00 7199 7.50 E82CC 3.50 MR 1C5GT 2.50 6980 1.60 6GS7 2.15 12CA5 1.95 307 5.00 EF94 0.85 KT81 4.00 P033 0.50 TTR-31 2.95 E83CC 3.50 65.00 6AC7 2.00 8GV7 2.50 12CX6 1.20 328A 15.00 7247 EF95 1.50 KT83 2.00 PY81 0.70 7380 13.50 E83F 5.50 TY2-125A86.00 1FD1 2.50 6AF4A 2.50 6GW6 2.50 1200138 3.50 388A 17.50 EF97 0.90 KT88 OSRAM P082 .70 7462 15.00 E88F 8.50 1G3GT 2.50 6405 1.50 6GY5 3.96 I 1213W44 3.50 42545 8.00 EF98 0.90 15.00 PY83 0.70 104.400 85.00 E88C 7.95 I 7475 5.00 PY88 0.86 T08-600W 1J3GT 2.50 6AG7 1.96 6H1 9.50 120W7 2.60 431U 4.50 E88CC 3.50 EF183 0.65 KTBB USA 9.96 7488 125.00 PY500A 1.95 385.00 1N2 4.50 64116 2.50 6H30 1.10 12E1 17.95 5728 65.00 E88CC Siemens EF184 0.85 KT68 GEC 14.95 7527 85.00 PY800 0.79 TYS2/250 1N5GT 2.50 6AJ4 2.00 6H8 1.95 12E14 38.00 7054 8.00 Special 6.96 EF730 1.80 KT 77 Gold Lion BH6GT 1.95 12GN7 3.95 708A 8.00 7551 8.95 I 1P28 BAJ7 2.00 EF731 3.60 10.95 PY801 375.00 25.00 7558 E90CC 7.96 2.75 105 0.90 6455 1.50 8HF5 6.50 112HG7 4.60 715C 45.00 9.45 EF732 3.50 5781 7.00 0.79 U18-20 7588 15.00 E90F 7.96 U19 11.95 1T4 0.70 13456 2.50 6HF8 2.50 12HG74 4.60 724A 275.00 EF800 11.00 5788 USA 10.96 QB3-300 54.95 7587 29.50 E91H 4.60 083-1750 U24 2.00 1U4 1.75 641.5 0.80 8H56 4.96 12J6GT 895 7284 75.00 EF804S 11.50 KT88 G Lion 7591A E92CC 3.96 tÚ5 1.00 6AM4 3.25 6J4 2.15 12J7GT 3.50 803 14.96 4.95 EF805S 13.50 18.95 139.50 U25 0.90 7809 47.00 E99F 8.99 U28 0.90 1X28 1.40 8AM5 8.00 8J4WA 3.15 12.128 2.96 805 39.00 E130L EF808S 14.50 5167 9.00 OB5-3500 7733 5.50 25.00 495.00 U37 9.00 122 8.95 6AM6 1.50 6J5 2.50 1255 1.95 807 1.95 EF812 0.85 KTGW81 2.50 6495 2.85 6J6 2.00 12K7GT 1.50 810 86.00 7788 25.00 EFL200 1.50 0E03-10 4.95 U41 6.95 2AS15A 11.50 E182CC 9.00 KTW62 2.50 1.50 6AN8A 2.66 6J7 4.15 1258 1.96 811A 15.00 7815 49.50 EH90 0.72 KTW63 2.00 QE08-200 U50 2.00 267 6180F 6.50 3.00 2822 59.50 64E15 1.75 BABA 4.50 12847GT 1.96 812A 35.00 7868 3.95 EK90 0.95 KTZ63 2.60 145.00 U82 8012 15.00 E186F 8.50 U191 0.70 2C394 32.50 6408 0.85 BJEBC 4.96 12SG7 4.75 813 23.50 EL32 0.96 L102I2K 8.95 QF40 65.00 8950 6188CC 7.50 U192 1.00 2C3984 39.60 641115 5.95 6JU8 2.50 12SH7 1.95 7.50 EL33 4.00 L120/2K 12.00 0P25 1.00 18042 10.50 E1T 15.00 QQE02-5 19.50 U193 0.86 2C40 37.00 8498 3.95 BJSBC 4.95 12557 1.95 8299 14.50 E280F 19.60 EL34 2.25 L87-20 96.00 12SJ7 18046 1000 QQE03.12 7.95 U251 1.00 2C42 29.50 8455 1.50 6J7G 4.15 1.50 833A 95.00 E283CC 10.00 EL34 Mullerd/ LS98 5.95 8458 2.60 6K 7G 2.00 12S07GT 1.95 866A 4.50 18048 11.50 Philips 4.50 M502A 80.00 QE03-20 35.00 0801 0.75 2C51 0.76 6288CC 13.60 1.50 6AS7G 4.50 EL38 1.95 M537A 60.00 QQEOB-40 UA8C80 0.86 2CY5 E810F 25.00 45.00 UAF42 1.00 2021 1.60 6418 0.75 61148 1.00 EL37 9.00 M5143 155.00 8478 1.75 AUDIO TAPE HEADS CALLERS WELCOME EL38 4.76 M8079 8.00 00V02-6 19.60 UBF80 0.60 2021W 2.50 61524 6.96 OQV03-10 5.50 UBC4/ 2.95 2E22 49.00 89114 2.00 pBEAD 1 GO OPEN MON -THUR 9AM- 5.30PM FRI EA60 EL41 3.50 M8082 7.50 BUMPING. 3 GO 1.00 OQV03-10 UBC81 1.50 2E26 7.95 6AU5GT 4.50 ].N EA76 1.95 EL42 2.00 M8083 3.25 INN HEN 9AM- 5.00PM MUllerd 15.00 UBF89 0.80 2J42 93.00 8408 0.95 EA79 1.95 EL81 8.95 M8091 7.50 6AV6 0.75 24 -HOUR ANSWERPHONE SERVICE' EL83 6.95 M8098 3.00 QQV03-20 UBL21 1.76 2J55 350.00 EABC80 0.70 25.00 UC92 1.20 2525 27.60 8AW8A 2.50 ELECTRO-OPTICAL ACCESS & BARCLAYCARD PHONE EAC91 2.50 EL84 Mullerd M8098 6.60 64X40T 1.95 2.95 M8099 5.00 00V03-208 UCC84 0.70 2525 Raytheon 22 00 ORDERS WELCOME EAF42 1.20 UCC86 0.80 76.00 64038 1.95 22.00 EL85 4.50 M8100 6.50 32.00 :0x14 EAF801 2.00 UCF80 1.00 2K26 96.00 6428 5.95 .x11.ASE 11. 00 UK ORDERS P &P E1 EL88 0.85 M8138 7.00 Q0V08-40A 6934 1.50 UCH21 1.20 2529 250 00 6B7 2.80 EL90 1.76 M8137 7.95 27.50 9/882 A99 C9184EE6 PLEASE ADD 15% VAT 6841 3.95 UCH41 2.60 2548 140.00 8B8G 1.50 6691 0.85 EL91 8.00 M8161 8.60 OGVOB-404 EXPORT ORDERS WELCOME 2.50 2556 250.00 BB10 1.95 GO EL95 1.75 M8162 6.50 Mullerd 46.00 UCH42 eN .rl11 0 E8C33 2.50 UCHB1 0.66 3A5 4.50 61346 0.95 0.21 la 2.00 CARRIAGE AT COST EL153 12.15 M8163 5.60 Q0V07-50 Nx 0 EBC41 1.96 83.60 UCL82 1.76 39 /1078 12.00 61347 4.50 EBC81 1.50 EL183E 3.50 M8190 4.50 ék 2.33 PLEASE SEND YOUR ENQUIRIES FOR UCL83 2.50 3A/108A 9.00 68989 3.50 BSI ó .ñ oCuOCT. EBC90 0.90 EL18P 3.50 M8195 8.50 00Z03-20 42.50 UF41 1.15 3A/109B 11.00 O.N NalO SPECIAL QUOTATIONS FOR LARGE EBC91 0.90 EL360 8.75 M8196 5.50 U23 1 73 EL500 1.40 QS]5/20 1.50 UF42 1.15 3A /110B 12.00 BOG 0 73 1017 1 /11 REQUIREMENTS. EBF80 0 95 M8204 5.50

CIRCLE 47 FOR FURTHER DETAILS.

ELECTRONICS & WIRELESS WORLD MAY 1986 1

www.americanradiohistory.com ThcArchcc 280 MC The SDS ARCHER - The Z80 based single board computer chosen by professionals and OEM users. * High quality double sided plated through PCB * 4 Bytewide memory sockets - upto 64k * Power -fail and watchdog timer circuits * 2 Serial ports with full flow control * 4 Parallel ports with handshaking * Bus expansion connector * CMOS battery back -up * Counter -timer chip * 4 MHz. Z80A OPTIONS: * SDS BASIC with ROMable autostarting user code * The powerful 8k byte SDS DEBUG MONITOR * On board 120 / 240 volt MAINS POWER SUPPLY * Attractive INSTRUMENT CASE - see photo. * 64k / 128k byte DYNAMIC RAM card * 4 socket RAM - ROM EXPANSION card * DISC INTERFACE card Shcrwood DataeS teffics Ltd Sherwood House, The Avenue, Farnham Common, Slough SL2 3JX.Tel. 02814- 5067 CIRCLE 18 FOR FURTHER DETAILS. RUGBY TIME? 5E0, 0A PSU MSF CLOCK IS EXACT i 8 Minutes and Seconds. DIGIT display of Date, Hours, SELF SETTING at switch -on, never gains or loses, automatic GMT /BST and leap year, and leap seconds. AC INPUT EXPANDABLE to Years, Months, Weekday and Milliseconds and 240V 50Hz use as a STOPCLOCK to show when something happened. COMPUTER or ALARM output also - parallel BCD (including Weekday), accurate minute and second pulses and audio to OPEN FRAME UNIT record and show time on playback. DIMENSIONS DECODES Rugby 60KHz atomic time signals, superhet receiver (available separately), built -in antenna, 1000Km range. 80W x 196L x 35H LOW COST fun -to -build kit (ready -made to order) with receiver. ONLY £89.80 includes ALL parts, 5 x 8 x 15 cm case, pcb, by- return CORNER and list of other kits. TIME RIGHT. MOUNTING postage etc PILLARS: - CENTRES 61 x 185 CAMBRIDGE KITS 45(WE) Old School Lane, Milton, Cambridge, Tel 860150 SPECIAL OFFER HI -SPEC TRANSFORMER TO BS41 5 LINEAR REGULATED PSU WITH 5v TRIMPOT FOR S100, V.M.E., EX STOCK - DIRECT FROM MANUFACTURER IBM, APPLE & PCB USERS TOROID FITTED THERMAL FUSE QTY DISCOUNTS OUTPUT FUSE ON PCB LIMITED QUANTITIES FULCRUM EACH P &P ALLOW (EUROPE) LTD INC + £1 14 DAYS FOR £11.50 VAT DELIVERY. Distribute and technically support over 180 different board levels products Make cheque (crossed) or P.0 for E1 2.50 payable to:- Select from manufacturers like

ST IVES WINDINGS LTD. MACROTECH INTERNATIONAL CORP. ADVANCED DIGITAL CORP. ACKERMAN DIGITAL SYSTEMS INNER ACCESS CORP. COMPUPRO DUAL SYSTEMS CORP. BICC.VERO INTERCONTINENTAL POST ST IVES WINDINGS LTD MICROSYSTEMS EARTH COMPUTERS INC. ILLUMINATED TECHNOLOGIES INC. INTEGRATED MICRO PRODUCTS EUROPEL SYSTEMS (ELECTRONICS) LTD. TADPOLE TECHNOLOGY PLC. DATA TO:- 4 Edison Road, Industrial Est. SYSTEMS CONSULTANTS CLASSIC TECHNOLOGY CORP.

ST IVES CAMBS. PE17 4LT CALL US ON (0621) 828763

Tel: 0480 62978 TELEX 826717 REF 110 VALLEY HOUSE, PURLEIGH, ESSEX CM3 60H. ENGLAND TELEX 946240 C WEASY G - Easylink I.D. 19010455 CIRCLE 14 FOR FURTHER DETAILS. CIRCLE 75 FOR FURTHER DETAILS. 14 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com 01 247 4060 Versatower: HARDWARE Price SOFTWARE MAC Price A range of telescopic towers in static Qume 1/2 Height D /Drive 65 EP Start 5 and mobile models from 7.5 to 36 Graphix Plus Card (Graphics Plus II) 80 Front Desk Scheduler 25 Hyperam Card Main St. Filer 17 metres with tilt -over facility enabling Megaplus Serial Option Megaform 60 Paradise Multidisplay Card Megafiler 34 all maintenance to be at ground level. Quadcolour Card Megamemerge 22 Smorgasbord 64K PFS Report 32 Visi -On Mouse PFS File 32 Designed in accordance with CP3 Chapter V; part 2; 49 + Parallel Helix Grappler 1972 for a minimum wind speed of 140 kph in Luxor 14 -inch colour monitor Macwrite 45 Cluster Adapt. IBM PC MacPaint 45 conditions of maximum exposure and specified by 54 Cluster Cable Kit IBM PC Omnis II professionals world -wide where hostile Cluster Program-IBM Management Edge 46 Plan 2000 Network Sales Edge 46 environments demand the ultimate in design, quality 50 Emudec Box Negotiation Edge and reliability. Dacom Buzzbox Modem Filevision 33 Mech Eng. 40 Suitable for mounting equipment in the fields of Intro to Science 5 Communications TK Solver 38 Music Works 11 Security surveillance - CCTV Mac Primer 2 Meteorology Stock Portfolio System 39 SOFTWARE APPLE Price Apple Mac Primer (Book) 3 Environmental monitoring Ouickfile II 40 Geographical survey Apple Access 11 IBM Price L Defence range -finding ASCII Express 24 SOFTWARE The Dictionary 12 SNA 3270 * RJE -IBM 110 Marine and aero navigation MailList Manager 25 VDTE Emulation 10 Floodlighting PFS File 30 CP/M 86 40 PFS Graph 30 Cobol Compiler -IBM 100 Airport approach lighting PFS Report 20 APL Program 30 Further details available on request: PFS Apple 20 Microsoft Cobol Compiler 136 Multiplan 12 Microsoft Basic Compiler 72 Supercalc II 49 Microsoft Basic Intptr 68 Think Tank II 35 PFS File -IBM 30 Systematics financial applications 50 PFS Graph -IBM 40 Systematics General Ledger 50 Cardbox -IBM 40 Systematics Purchase Ledger 50 PC Blast 70 Forth 33 D. Graph 43 Workbench 40 PC Tutor Intro to DOS 10 STRUMECH ENGINEERING LIMITED Vlasak Sales Ledger 30 PC Tutor 10 14 Portland House, Coppice Side, Brownhills Softcard 60 System Build Budget England Apple Ill System Software 33 System Build Cashflow 14 Walsall, West Midlands WS8 7EX, Visicalc Manual 3 System Build Fin Rep 14 Telephone: Brownhi.Is (0543) 374321 Viside 30 System Build Multi Regres 14 Telex: 335243 SEL.G. Pascal 40 System Build Mail Shot 14 Orbit 30 System Build Project 14 Busifile (Management Info) 33 System Build Sales F /Cast 14 Quickfile 10 Easyfiler 33 PHONE NOW! STOCK IS STRICTLY LIMITED First come -first served! CIRCLE 8 FOR FURTHER DETAILS.

HIGH PERFORMANCE LOGIC ANALYSER

The TA3000 is a high performance modular logic analyser which interactively combines up to 16 channels of 100MHz Timing analysis with up to 96 channels of 20MHz State analysis controlled by a powerful multi -level conditional trigger -trace sequencer.

E Flexible, expandable, modular design D Up to 112 channels E 100MHz Timing, 20MHz State D Multi -level conditional triggering D State/Timing cross -triggering and correlation D Easy to use softkey control D CP /M PLUSt operating system D IEEE -488, RS -232 and parallel printer interfaces

For further information contact: Thandar Electronics Ltd., London Road, St. Ives, Huntingdon, Cambridgeshire PE17 4HJ. Telephone: 0480 -64646. Telex: 32250. thandar tCP /M PLUS is a trademark of D'gkai Research Inc. ELECTRONICS LIMITED

CIRCLE 56 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MAY 1986 15

www.americanradiohistory.com icOMPUTER WAREHOUSE FOR-W&1 IR TSE ALLADINS CAVE OF COMPUTER AND ELECTRONIC EQUIPMENT 4. NOT LINE DATA BASE ©* DON'T MISS THE CPM Deal 4.* DISTEL OF the CENTURY The ORIGINAL FREE OF CHARGE dial up data The FABUL U CPM TATUNG P 2000 base. Buy, browse or place YOUR OWN AD for goods or services to sell. 1000's of stock items, Professional Business System spares and one off bargains. Updated daily. A cancelled export order and months of negotiation enables us to offer this professional ON LINE NOW CCITT, 8 bit word, no parity. PC, CPM system. recently on sale at OVER £1400, at a SCOOP price lust over the cost of the two internal disk drives!! less For 300 baud modems call 01 -679 1888 Or than the price of a dumb terminal!! For 1200-75 baud modems call 01 -679 6183 Not a toy, the BIG BROTHER of the EINSTIEN computer, the DUAL PROCESSOR PC2000 comprises a modern stylish three piece system with ALL the necessities for the SMALL BUSINESS, INDUSTRIAL, EDUCATIONAL or HOBBYIST USER. Used with FREEYour monitor from its compute! For the THOUSANDS of proven, tested and available CPM software packages such as £24.95 it becomes a SUPERB WORDSTAR, FAST, DBASE2 etc, the PC2000 specification, at our prices, CANNOT HIGH QUALITY COLOUR' TV SET BE BEATEN!! The fabulous TELEBOX an INVALUABLE MUST for the owner of The central processor plinth contains the 84K, ZBOA processor, DUAL TEAC 55F 51/4" ANY video monitor with a composite input, colour or monochrome Double sided 40/80 track disk drives (1 Mb per drive), PSU, 4K of memory mapped screen RAM, disk controller, RS232, Made by a major UK Co as a TOP QUALITY, stand alone UHF CE NTRON ICS and system expansion ports, and if that's not enough a ready to plug into STANDARDS" DRIVE port for up to FOUR tuner and costing OVER C75 to manufacture this opportunity to 8' disk drives either in double density or IBM format The ultra slim 92 key, detachable keyboard features32 user definable keys give your monitor a DUAL FUNCTION must not be missed! The numeric keypad and text editing keys even its own integral microprocessor which allows the main Z80A to devote ALL its time to TELEBOX consists of a compact stylish two tone charcoal USER programs, eliminating "lost character' problems found on other machines The attractive, detachable 12" monitor combines moulded case containing ALL electronics tuner, power supply etc a green, anti-glare etched screen with full swivel and tilt movement for maximum user comfort Supplied BRAND NEW with CPM to simply plug in and convert your previously dedicated computer 2.2, user manuals and full 90 day guarantee. Full data sheet and info on request monitor into a HIGH QUALITY COLOUR' TV SET, giving a real PC2000 Wordpprocessor System benefit to ALL the family!!! Don't worry if your monitor doesn't have PC2000 System PC2000 Business System with CPM wi th CPM and T E C FP25 daisywheel sound - THE TELEBOX even has an integral4 watt audio amplifier with CPM Etc. and 'Ready to Run' FAST Sales and printer for driving an extemal speaker, PLUS an auxiliary output for superb COST OVER £1400 Purchase ledger, supports up to quality television sound via your headphones or HI Fl system etc 9000 Accounts, VAT etc. Other features include Compact dimensions of only 1575" w x NOW COST OVER £1 700 NOW only £_ 7.5" d x 3.5" It latest technology, BRITISH manufacture fully - tuneable7 channel push button tuner, Auto AGC circuit, SAW f ilter, £399 NOW LED status indicator fully isolated 240v AC power supply for total only £499 safety, Mains ON -OFF switch etc. Many other uses Carriage & Insurance LIMITED QUANTITY- DON'T MISS THIS OFFER!!! MODEMS SURPLUS SPECIALS' 01f Join the communications revolution with our super ONLY £24.95 OR £19.95 if purchased with ANY of our range of DATA MODEMS prices and specifications Video monitors Supplied BRAND NEW with full instructions and 2 YEAR PRESTEL - VIEWDATA - TELEX to suit all applications and budgets..... PLESSEY VUTEL, larger BRAND NEW State of the art products warranty. Post and packing £3.50 When used with colour crt ultra compact unit, slightly DACOM DSL2123 Multi standard 300 -300, 1200 -75 than a telephone features A STANDARD DTMF TELEPHONE (tone dial) with 5" CRT monitor and Auto answer etc £268.00 integral modem for PRESTEL, DACOM DSL2123A0 Auto dial, smart modem with COLOUR 6 MONOCHROME etc. direct connection to multi standard AUTO SPEED and data buffer VIEWDATA etc. Designed to sell to the EXECUTIVE at detect with flow control etc £365.00 ' over £600!! Our price BRAND NEW AND BOXED at MONITO SPECIALS only £99.00 DACOM DSL2123GT The CREAM of the intelligent modems, dial, auto index, 'SYSTEM ALPHA' 14" COLOUR MULTI INPUT MONITOR DECCAFAX VP1 complete Professional PRESTEL auto call buffer Made by the famous REDIFFUSION Co. for their own professional computer etc etc £498.00 system in slimline desk top unit containing Modem. V22 1200 baud FULL DUPLEX system this monitor has all the features to suit your immediate and future Numeric keypad, CPU, PSU etc. Connects direct to Steebeck SB1212 requirements Two video inputs RGB and PAL Composite Video, allow direct RGB monitor. features sync or asynq optional auto dial £485.00 standard colour Many other TRANSDATA Acoustic coupler 300 baud full connection to BBC/IBM and most other makes of micro computers or VCR's, include: Printer output, Full keyboard input, 307A Cassette duplex, originate only, RS232 interface including our very own TELEBOX An internal speaker and audio amp may be port etc. BRAND NEW with DATA. A FRACTION OF £49.00 connected to computer or VCR for superior sound quality. Many other features COST only £55.00 PIL tube, Matching BBC case colour, Major controls on front panel Separate Ex BRITISH TELECOM full spec, CCITT, ruggedised ALPHATANTEL. Very compact unit with integral FULL work Contrast and Brightness - even in RGB mode Separate Colour and audio keyboard. TV bargain offers Sold TESTED with data Will on ALPHA NUMERIC Just add a domestic any MICRO or system with RS232 interface. controls for Composite Video input BNC plug for composite input 15 way 'D' a PRESTEL receiver and you have superb system and MODEM 13A baud unit, 2" high fits under plug for RGB input modular construction etcetc via PRESTEL the cheapest TELEX service to be 300 only This Must Be ONE OF THE YEAR'S BEST BUYS. PC USER phone CALL mode only £45.00 _ found!! Many features: CENTRONICS Printer output, MODEM 20.1. 75 -1200 baud Compact unit for use Supplied BRAND NEW and BOXED, complete with DATA and 90 day Memory dialling etc. with data and Supplied complete as subscriber end to PRESTEL, TELECOM guarantee ONLY £149.00 as above OR IBM PC Version £185.00 DIY mod for ROB or Composite video outputs. AS GOLD, 15 Day skt £1.00, BNC skt 75p BBC interface cable £5.50 MICRONET etc £39.95 +pp £6.50 NEW only £125.00 MODEM 20-2 1200-75 baud Same as 20-1 but for Post and packing on all PRESTEL units £8.50 DECCA 8016" COLOUR monitor. RGB Input computer end £85.00 +pp £6.50 Little or hardly used manufacturers surplus enables us to otter this special EX-STOCK DATEL 2412. Made by SE Labs for BT this two part converted DECCA RGB Colour Video TV Monitor at a super low price of only INTEGRATED CIRCUITS unit is for synchronous data links at 1200 or 2400 £99.00, a price for a colour monitor as yet unheard of!! Our own interface, 4164 200 ns D RAMS 9 for £11 4116 ns baud using 2780/3780 protocol etc Many features safety modification and special 16" high definition PIL tube, coupled with the include 2 or 4 wire working, sel test auto answer etc DECCA 80 series TV chassis give 80 column definition and quality found only £1.50 2112 £10.00 2114 £2.50 2102 £2.00 6116 £2.50 EPROMS 2716 £4.50 2732 £3.00 COST OVER £800. Our price ONLY £199 +pp £8.00 on monitors costing 3 TIMES OUR PRICE. The quality for the price has to be DATEL 4800, RACAL MPS4800 baud modem, EX 2764 £4.95 27128 £5.50 6800 E2.50 6821 £ 1 seen to be believed! Supplied complete and ready to plug direct to a BBC BT good working order, ONLY £295.00 +pp £8.00 MICRO computer or any other system with a TTL RGB output Other features 68A09 £8 6BB09 £10 8085A £5.50 8086 £15 are: internal speaker, modular construction, auto degaussing circuit attractive 8088 £8 NEC765 £8 WD2793 £28 8202A SPECIAL OFFER TEAK CASE, compact dimensions only 52cm W x 34 H x 24 D, 90 day £22 8251 £7 8748 £15 Z80A DART £6.50 MODEM TG2393. Ex BT, up to 1200 baud full guarantee Although used units are supplied in EXCELLENT condition. Z80A duplex 4 wire or half duplex over 2 wire line. ONLY CPU £2.00. Thousands of IC's EX STOCK +pp ONLY £99.00 + Carriage. send SAE for list. £85.00 PER PAIR £10.00 DECCA 80 18" COLOUR monitor. Composite video Input Same as above F.r more information contact our Sales Office. model but fitted with Composite Video input and audio amp for COMPUTER, VCR or AUDIO VISUAL use ONLY £99.00 + Carr. DISK DRIVES MATRIX PRIM ' S REDIFFUSION MARK 3, 20" COLOUR monitor. Fitted with standard 75 ohm SPECIAL BULK PURCHASE of these compact, high Japanese 51/4 half height, 80 track double sided disk composite video input and sound amp This large screen colour display is ideal speed matrix printers. Built in Japan for the Hazeltine for SCHOOLS SHOPDS DISCOS, and other AUDIO VISUAL appli- drives by TEAC. CANON, TOSHIBA etc CLUBS as NEW with 90 Corporation this unit features quality construction cations Supplied in AS NEW or little used condition ONLY £145.00 + Carr. Sold day guarantee ONLY £85.00 giving 100cps bidirectional, full pin addressable TEC Fß503 Double sided HH 40 TRK NEW £75.00 BUDGET RANGE EX EQUIPMENT MONOCHROME video monitors. graphics, 6 type fonts, up to 9.5' single sheet or SUGART SA400 SS FH 35 TRK £55.00 handling, RS232 All units are fully cased and set for 240v standard working with composite video FDD100 FH 40 TRK tractor paper and CENTRONICS SIEMENS SS £65.00 parallel interface. Many other features. BRAND NEW inputs Units are pre tested and set up for up to 80 column use. Even when carriage on 51/4" drives £5.50 and BOXED. COST £420. Our price Only £1 99.00 MINOR screen burns exist - normal data displays are unaffected 30 day Brand NEW metal 51/4" DISK CASES with internal PSU. guarantee DSKC1 for 2 HH or 1 FH drive £29.95 +pp £4.00 12" KGM 320.1 B/W bandwidth input will display up to 132 x 25 lines £32.95 DSKC 2 for 1 HH drive £22.95 +pp £3.50 12" GREEN SCREEN version of KGM -1. Only £39.95 320 DKSC 3 As DSK1 LESS PSU £12.95 +pp £2.50 Dry Fit MAINTENANCE FREE by Sonnenschein 9" KGM 324 GREEN SCREEN fully cased very compact unit. Only £49.00 DSKC 4 As DSK2 LESS PSU +pp £2.00 £10.95 & Yuasa. Carriage and insurance on all monitors £10.00 8" IBM format TESTED EX EQUIPMENT. 5 1 2v 3Ah SHUGART800 /801 SS £175.00 +pp £8.50 A300 0719131 NEW £13.95 71 A300 071 9131 2 6v 3Ah NEW £9.95 I SHUGART851 DS £250.00 +pp £8.50 TWIN SHUGART851's2 Mb total capacity in smart case, A300 07191202 6 -0 -6v 1.8Ah TESTED Ex complete with PSU etc £595.00 Equip £5.99 GOULD OF443 enclosed, compact switch mode supply with DC regulated MITSUBISHI M2894-83 8" DS 1 Mb equiv. to SHUGART of +5v @ @ outputs 5.5a, +12v 0.5a -12v @ 0.1a and -23v @ 0.02a Dim 18 x SA850R. BRAND NEW at £275.00 +pp£8.50 11 x 6 cm. 110 or 240v input BRAND NEW only £16.95 DYSAN Alignment disk £29.00 + pp £1.00 VDU TE GOULD 8" MINALS G6-40A 5v 40 amp switch mode supply NEW £130.00 Various disk drive PSLls Ex Stock SEE PSU section. Standard VDU data entry terminals AC -DC Linear PSU for DISK drive and SYSTEM applications. Constructed on a HARD DISK DRIVES rugged ALLOY chassis to at give away prices!! continuously supply fully regulated DC outputs of +5v DRE/DIABLO Series 30 2.5 Mb front load £525.00 QUME OVT108. Current product, state of the art @ 3 amps, @ 0.6 amps @ -5v and +24v 5 amps. Short circuit and overvoltage Exchangeable version £295.00. ME3029 PSU £95.00 terminal with detachable keyboard, 12" Green screen, protected. 100 or 240v AC input. Dim 28 x 12.5 x 7 cm NEW £49.94 DIABLO44 /DRE4000A, B 5+5 Mb from £750.00 2 page RAM, TVI 925, Hazeltine, ADMSA emulations, Carriage on all PSU's £3.00 CDC HAWK 5+5 Mb£795.00. CDC 9782 80 Mb RMO3 software setup, 25 x 80, Clock, Swivel and tilt base, etc Printer port, Function keys etc. BRAND NEW and /[ T PERTEC D3422 5+5 Mb £ £405.00 BOXED AT ALMOST HALF PRICE Only £425.00 1'4 4 ` L L I T-I Manufacturers BRAND NEW surplus RODIME 51/4" Winchesters ex-stock from £150 CALL AJ510 - EX RENTAL, Z80 controlled, 15" green 'I. Clearance items- Sold as seen- No guarantee screen 24 x 80 display, graphics, cursor addressing, DEC LA34 Uncoded keyboard with 67 quality gold plated switches on X -Y matrix- ideal micro conversions etc £24.9 ICL 2314 BRAND NEW 14" Mb Removable pack hard printer port etc. Very good condition TESTED complete AMKEY MPNK114 Superb word processor chassis keyboard on single PCB disk drive, cost over £2000 with data ONLY £99.00 with manual only £225.00 with 116 keys Many features such as On board Micro, Single 5v rail full ASCII BASF 6172 8" 23Mb Winchesters £199.00 ADDS 520 - Dumb terminal, used, 12" b/w screen coded character set with 31 function keys, numeric keypad, cursor pad Unless stated all drives are refurbished with 90 day RS232 interface and printer port. TESTED. and 9600 baud SERIAL TTL ASCII OUTPUT!! Less than half price guarantee Many other drives and spares in stock- call ONLY £125.00. Carriage on terminals £10.00 Only £89.00 with data Carriage on Keyboards £3.50 sales office for details 100's of other terminals in stock CALL for more details. A All prices quoted are for U.K. Mainland, paid cash with order in Pounds Sterling PLUS VAT. Minimum order value E .00. Minimum Credit Card orderEl0.00. Minimum BONA FIDEaccount ordersfrom Government Depts., Schools, Universities and established companiesE 20.00. Where post and packing not indicated please ADD £1.00 + VAT. Warehouse open Mon -Fri [.'I.DF: L 9.30 -5.30. Sat 10.30 -5.30. We reserve the right to change prices and specifications without notice. Trade. Bulk and Export I _ 1 r I i 1:1 32 Biggin Way, Upper Norwood, London SE19 3XF i± 1_i ! I h i II I I L DI Telephone 01 -679 4414 Telex 894502 Data 01 -679 1888

16 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com FRS - PRINTERS - PRINTERS - PRINTERS SUPER DEAL? NO - SUPER STEAL TELETYPE ASR33 GE TERMIPRINTER THE FABULOUS 25 CPS "TEC STARWRITER" DATA I/O TERMINALS /// Industry standard, combined ASCII 110 baud printer, keyboard and 8 hole paper tape punch and reader. Made to the very RS232 serial interface. highest spec the TEC Standard STARWRITER Ideal as cheap . hard copy unit FP1500.25 features a or tape prep. for CNC and NC very heavy duty die cast machines. TESTED and in good chassis and DIABLO condition. Only £250.00 floor type print mechanism giving superb stand £10.00. Carr & Ins. £15.00. A massive purchase of these desk top registration and print a fraction printer terminals enables us to offer you quality. Micro-processor of its original cost. these quality 30 or 120 cps printers electronics offer full at a SUPER LOW PRICE against their DIABLO /OUME command compatability and tull con ro via CPM WORDSTAR EX NEWS original cost of over £1000. Unit ETC. Many other features include bidirectional printing, switchable 10 or 12 pitch, comprises of full OWERTY, electronic full width 381 mm paper handling with up to 163 characters per line, friction feed keyboard and printer mech with print rollers for single sheet or continuous paper, internal buffer, standard RS232 serial SERVICE PRINTERS face similaF to correspondence quality interface with handshake. Supplied absolutely BRAND NEW with 90 day guarantee typewriter. Variable forms tractor unit and FREE daisy wheel and dust cover. Order NOW or contact sales office for more enables full width - up to 13.5" 120 information. Optional extras RS232 data cable £10.00. Tech manual £7.50. Tractor Compact ultra reliable quality built unit column paper, upper - lower case, Feed £140.00. Spare daisy wheel £3.50 Carriage 8 Ins. (UK Mainland) £10.00. made by the USA EXTEL Corporation. standard RS232 serial interface, internal Often seen in major Hotels printing up to vertical and horizontal tab settings, the minute News and Financial inform- standard ribbon, adjustable baud ation, the unit operates on 5 UNIT rates, quiet operation plus many other NOW ONLY £499 + VAT BAUDOT CODE from a Current loop, features. Supplied complete with manual. RS232 or TTL serial interface. May be Guaranteed working GE30 £130.00. connected to your micro as a low cost GE1200 120 cps £175.00 Optional floor printer or via a simple interface and filter Untested GE30 £65.00 £12.50. Carr & Ins. £10.00. to any communications receiver to stand DIY PRINTER MECH enable printing of worldwide NEWS, TELEX and RTTY services. SEMICOND UCTOR Brand New surplus of this professional printer chassis gives an Supplied TESTED in second hand opportunity for the Student, Hobbyist or Robotics condition complete with DATA, 50 and 'GRAB BAGS' outstanding 75 xtals large paper roll. constructor to build a printer - plotter - digitiser etc, entirely to their baud and TYPE AE11 Mixed Semis amazing value contents own specification. The printer mechanism is supplied ready built, include transistors digital, linear, IC's, aligned and pre tested but WITHOUT electronics. Many features 50 Column ONLY £49.95 triacs, diodes, bridge recs, etc. etc. AE1 1 include all metal chassis, phosphor bronze bearings, 132 character Spare paper roll for £4.50 All devices guaranteed brand new full 2 12V TYPE AF11 R 72 Col. manufacturer's markings, fully optical shaft position encoder, NINE needle head, x two phase £65.00 spec with stepper motors for carriage and paper control, 9.5" Paper platten etc. + Ribbon guaranteed. TYPE AH11 R 80 Col. 100+ £5.15 a print sample to show the unit's capabilities!! 50+ £2.95 etc. Even manufacturer's ASCII /BAUDOT £185.00 TTL 74 Series. A gigantic purchase of an Overall dimensions 40 cm x 12 cm x 21 cm. Carriage and Insurance £7.50 "across the board" range of 74 TTL series Sold BRAND NEW at a FRACTION of cost ONLY £49.50 + pp £4.50. IC's enables us to offer 100+ mixed "mostly TTL" grab bags at a price which two or three chips in the bag would normally cost to buy. Fully guaranteed all IC's full spec. 100+ £6.90, 20,000 FEET OF ELECTRONIC 200+ £12.30, 300+ £19.50 AND COMPUTER GOODIES ENGLAND'S LARGEST SURPLUS STORE- SEEING IS BELIEVING!' MAINS FILTERS CURE those unnerving hang ups and data glitches caused by mains interference with professional quality filters. SD5A match- DEC CORNER MAG TAPE DRIVES box size up to 1000 watt 240 V Load ONLY £5.95. L12127 compact Many EX STOCK computer tape drives and spares by completely cased unit with 3 pin fitted PDP 1140 System comprising of CPU, 124k socket up to 750 watts ONLY £9.99. memory & MMU 15 line RS232 interface. PERTEC, CIPHER, WANGO, DIGIDATA, KENNEDY RPO2 40 MB hard disk drive. etc. Special offer this month on DEI Cartridge tape TU10 9 track 800 BPI Mag tape drive, dual EPROM COPIERS track system. VT52 VDU, etc. etc. Tested and drives ONLY £450.00 each. running. £3,750.00 CALL FOR DETAILS The amazing SOFTY 2 The "Complete BA11 -MB 3.5" Box, PSU, LTC £395.00 Toolkit" for copying, writing, modifying and DH11 -AD 16" x RS232 DMA listing EPROMS of the 2516, 2716. interface £1,900.00 COMPUTER/SYSTEM CABINET â PSU 2532, 2732 range. Many other functions DLV11 -J4 x EIA interface £350.00 All in one quality computer cabinet with integral include integral keyboard, cassette inter- DLV11 -E Serial. Modem support £190.00 face, serial and parallel i/o UHF modulator DUP11 Synch. Serial data i/o £650.00 switched mode PSU, mains filtering, and twin fan ZIF socket etc. D0200 Dilog - multi RK controller £495.00 cooling. Originally made for the famous DEC PDPB ONLY £195.00 + pp £2.50. DZ11 -B 8 line RS232 mux board £650.00 computer system costing thousands of pounds. "GANG OF EIGHT' intelligent Z80 KDF11 -B M8189 PDP 1123 Made to run 24 hours per day the psu is fully controlled 8 gang programmer for ALL PLUS £1,100.00 screened and will deliver a massive +5v DC at 17 amps, +15v DC at single 5v rail EPROMS up to 27128. Will LA30 Printer and Keyboard £80.00 1 amp and -15v DC 5 amps. The complete unit is fully enclosed copy 8 27128 in ONLY 3 MINUTES. Internal LA36 Decwriter EIA or at with removable top lid, filtering, trip switch, power and run leds LCD display and checking routines for 20 mA loop £270.00 IDIOT PROOF operation. Only £395.00 + MS11 -JP Unibus 32kb Ram £80.00 mounted on ali front panel, rear cable entries, etc. etc. Units are in pp £3.00. MSI1 -LB Unibus 128kb Ram £450.00 good but used condition - supplied for 240v operation complete with "GANG OF EIGHT PLUS" Same spec. as MS11 -LD Unibus 256kb Ram £850.00 full circuit and tech. man. Give your system that professional finish above but with additional RS232 serial PDP11 /05 Cpu Ram, i/o etc £450.00 for only £49.95 + carr. 19" wide 16" deep 10.5" high. Useable area interface for down line loading data from PDP11 /40 Cpu, 124k MMU £1,850.00 16" w 10.5 "h 11.5 "d. computer etc. ONLY £445.00 + pp £3.00 RT11 ver 38 documentation kit £70.00 RK05 -J 2.5 Mb disk drives £650.00 Also available less psu, with fans etc. Internal dim. 19 "w, 16 "d, 10.5 "h. Data sheets on request KL8 JA PDP 8 async i/o £175.00 £19.95. Carriage £8.75 M18E PDP 8 Bootstrap option £75.00 VT50 VDU and Keyboard ELECTRONIC COOLING FANS -20 mA £175.00 COMPONENTS 66% DISCOUNT ON Keep your hot pans COOL and RELIABLE with our range of VT52 VDU and RS232 interface £250.00 EQUIPMENT COLING FANS ETRI 126LF21 240v 5 blade equipment fan Om. 80 x 80 x 38mm E9.95. ETRI 99XUOI 240v Slimline a Due to our massive bulk purchasing programme, which enables us to bring you the Dim. 92 x 92 o 25mm. equipment glen. NEW 0.95. GOULD J8-3AR Dim. 3' o 3' x 2.5' compact vary quiet Give your VT100 a Birthday!!! best possible bargains, we have thousands of ICs, Transistors, Relays, Caps, PCBs, running 240v operation. NEW E6.95. MUFFIN- CENTAUR- Brand New VT100 Keyboards Sub -assemblies, Switches etc. etc. surplus to OUR requirements. Because we don't BOXER standard 120 x 120 n 38mm fans Order 110v OR have sufficient stocks of any one item to include in our ads we are packing all these 240v. 3 or 5 blade. NEW at E10.50 or tested EX EQUIPMENT only £85.00 E5.50. Low Voltage DC Fans. BUHLER 89.11.22. 8.16v DC items into the BARGAIN OF A LIFETIME. Thousands of components at giveaway micro rotinaiature reversible. Uses brushless servo motor. 1000's OF EX STOCK spares for POPS, PDP8A prices. Guaranteed to be worth at least 3 times what you pay. Unbeatable value and almost silent running. guaranteed 10.000 hr life. Measures PDP11, PD P1134 etc. SAE. for list. or CALL perhaps one of the most consistently useful items you will every buy!!! Sold by only 62 x 62 x 22mm. Cc"ent cost E35.00 OUR PRICE sales for ONLY E13.95 complete with data. 120 o 120 x 38mm 14' office details. weight. DC lens/. PANSONIC FB- 12C12H 12c DC 5 blade E18.00 ALL TYPES OF COMPUTER EQUIPMENT AND 2.5k1s £5.25 + pp £1.25 5 kls £6.90 + £1.80 PAPST 4124X 24 - 28v DC 5 blade E18.00. SPARES WANTED FOR PROMPT 100's of other fans Es Stack. CASH 1 okIS £11.25 + pp £2.25 20kls £19.50 + pp £4.75 PAYMENT. Call for Details. Post A Packing on all fans E2.00 1000's of other EX STOCK items including POWER SUPPLIES, RACKS, RELAYS, TRANSFORMERS, TEST EQUIPMENT, CABLE, CONNECTORS, HARDWARE, MODEMS, TELEPHONES, VARIACS, VDU'S, PRINTERS. POWER SUPPLIES, OPTICS, KEYBOARDS etc. etc. Give us a call for your spare part -, ./ requirements. Stock changes almost daily. !Y Don't forget, ALL TYPES and QUANTITIES of electronic surplus purchased for CASH V

CIRCLE 70 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MAY 1986 17

www.americanradiohistory.com by J.D. Last, Ph.D., M.I.E.E. (GW3MZY) New directions for marine dlf Marine d/f is dying, long live marine d /f.

Dr David Last is a Senior Lecturer A'though radio direction - 500 beacons in Europe and modulating the signals of each in the School of Electornic En- finding is the oldest North Africa are organized group of beacons with a dif- gineering Science at the University and simplest form of under an old intergovernmental ferent audio tone, one of a set of College of North Wales, Bangor radio navigation, it is still the agreement the Paris Plan of tones between 354 and 1052Hz. where he teaches Microelec- - one installed on the idea is for to tronics. Although he has greatest 1951. The prime object of the The operators researched and published papers number of ships, and Paris Plan was to minimize in- measure bearings by turning and patents in the fields of aeronautical radio-beacons out- terference between radio - their receiving aerials until they semiconductor and integrated number all other radio naviga- beacons, but in achieving this hear a null in the tone of the circuit devices and non -linear tion aids for aircraft. The laudable aim the Plan has wanted beacon, all interfering circuits he now spends most of his technology of direction -finding, seriously inhibited the develop- tones being carefully ignored - time on radio systems. He was developed before the first' ment of radio direction -finding. the `audio null' method of joint winner of a Design Council World War, has been changing To see how this has happened direction -finding. award recently for the rear -heater rapidly, the latest receivers - and how the new Geneva Beacons may be identified by radio receiving aerial for cars employing microcomputers and agreement has freed the logjam the callsigns which they trans- described in February, E & WW. He data -processing techniques. In we must look at the way the mit in Morse code uni- concentrates largely on radio - - or by the navigation systems for ships, parallel with these develop- Paris plan attempted to squeeze que combination of carrier fre- aircraft and land vehicles - with a ments in the technology, an a quart of beacons into a pint - quency, tone and time -slot. special interest in remote tracking inter-governmental radio con- pot of spectrum. When the systems was and automatic vehicle location ference held in Geneva" The marine radio- beacon fre- designed, some 35 years ago, systems and acts as a Consultant agreed radical changes in the quency band, from 285 to radio direction -finding was the on radio navigation and transmission formats of 315kHz, is divided into just 14 principal radio navigation aid communications to a number of maritime radio -beacons. These channels, spaced 2300Hz apart for ocean -going and coastal companies and public bodies. open the door to the develop- (top of Fig. 3). However, so ships. Installation was made ment of a new generation of many beacons must share each mandatory under the Safety of receivers which promise to channel that it is only possible Life at Sea Convention for all revolutionize radio direction - to space co- channel groups suf- ships of more than 1600 tons. finding. ficiently far apart to achieve The receivers on these 'Con- Alongside the most modern about 14dB of the 30dB protec- vention ships' must meet type - techniques, the earliest method tion ratio on which the Plan is approval specifications based of direction -finding - turning based. on the Paris Plan. But ironical- the aerial by hand until the The remaining 16dB of pro- ly, the great majority of these signal received is at a minimum tection is obtained by amplitude receivers are operated as and then noting the direction in which the aerial is pointing - is still in widespread use. Automatic direction -finders employ a similar technique and a pointer shows the bearing of the transmitter relative to the heading of the ship, as in Fig. 1. From this relative bearing and the magnetic heading measured by a compass, the bearing of the radio -beacon is calculated Fig. 1. Fixing the position and a line of position drawn of a ship by taking through the location of the bearings on two radio - beacon on a chart. Two or more beacons. The automatic such lines of position should direction -finder shows the intersect at the receiver. bearing of the beacon Maritime radio -beacons are relative to the ship's simple, low- frequency, non - heading. The compass directional transmitters install- measures the heading ed at coastal sites and on light - relative to magnetic north vessels. Figure 2 shows some of and these two the beacons which serve the measurements give the English Channel. The frequen- magnetic bearing of the cies, power levels and transmis- beacon. sion standards of the more than 18 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com automatic direction -finders, The most sophisticated small - automatically seeking the null craft direction -finders are very 3011 kHz 354111. Dover Strait Group direction of the carrier signal - advanced. Taking bearings North Foreland NF SO L. 3057kHz .500Hz FS 50 not the modulation - so the in- under microprocessor control 1 Falls L.V. terference protection provided and storing the positions of 2 Tongue L.V. Gu 30 by the audio tones is lost. beacons in memory, they 303 4kHz 444Hz 3 West Hinder WH 20 Moreover, these receivers are calculate the ship's position and 1 4 Chichester Bar CH 10 4 Ostende OE 30 2 5 Brighton Marina BM 10 5 Calais CS 20 less frequently display it as a latitude and used much 3, 6 Newhaven NH 10 6 East Goodwin L.V. GW 30 nowadays because the ships longitude or even as a bearing carry radar, Decca or satellite to steer and distance to run to r' navigation systems which give the next viewpoint;. 303 4kHz ,: © Poole PO 10 r more accurate fixes, auto- But all these receivers, just 3.6 ow, matically and continuously. So like the Convention ship ones, .06 the people for whom the system measure bearings using the car- 0 was designed don't often use it rier only and ignore the aduio 4 m® "v 4 - and when they do they don't modulation. So they all 1 use it as it was designed to be dispense with the protection used! provided by the audio tones. , Instead, the main customers This is one of several ways in © Channel East Group of the radio-beacons are the which the radio -beacon system, 310.3kHz 752 Hz - pleasurecraft sailors - relative- which now looks very old 1 Brassurelle L.V UL SO ly rare birds in 1951 but found fashioned in concept, is out of © 2 Royal Sovereign RY 50 in large flocks now. They step with its users (and their 3 Ailly AL SO few elec- receivers). Other problems in- 4 Cop d'Alprech PH 20 generally carry other Gris Nez GN 30 of Channel Central Group s Cap tronic navigation aids, so radio clude a shortage channels 6 Dungeness DU 30 direction -finding - still the which is seriously inhibiting the 291.9 kHz 670 Hz 1 Portland Bill PB 50 form of radio - development and improvement cheapest 2 St Catherine's Pt. CP 50 important of the service, especially in 296 5kHz navigation - is very 3 Antifer TI 50 to them. It has been estimated areas of dense shipping move- Le Havre L.Buo BG 510 that more than 70,000 d/f ment. But, of course, the chan- 5 Ver ER 20 receivers were sold by UK nels are few because the 6 Pte. de Barfleur FG 70 manufacturers in the decade up transmissions are wide - wide to 1983, principally to pleasure - enough to accommodate the craft sailors. modulating tones which the Fig. 2. Radio -beacons covering the English Channel. Small-craft receivers don't users ignore! Most are arranged in groups of six, transmitting in have to be type-approved nor The six -minute transmission turn on the same frequency. Each table shows the conform to the Paris Plan. This sequence is also very un- carrier and modulation frequencies of the group and has freed designers to be highly popular. Navigators want the names, callsings and protected ranges of the innovative in developing frequently- updated position individual beacons. receivers for this large market, fixes with no 'skew' errors due which demands ease of opera- to the movement of the ship in 287.5 7988 3011 3034 313.5 tion, low cost and high perfor- the intervals between taking used Upper mance - preferably simultane- the two or more bearings limit limit ously! to plot the fix; a ship travelling nn F117 n L n ( a For example, one popular at 20 knots may sail nautical 285 300 315kHz receiver has only 10% of the mile in the interval between volume, 6% of the weight, 4% measurements on beacons in Ó Ó of the cost and 0.14% of the the same group. A few bea- rO power consumption of a Con- cons generally low- powered - Upper Though a ones operate continuously at vention ship receiver! - limit limit few small craft receivers are present; it would be desirable cheap and nasty, at least one for all beacons to do so or to be 285 300 `- claims to meet the type - in groups of three at the most. approval specification for con- The Paris Plan actually Fig. 3. Channel assignments in the I.f. /m.f. marine vention ship receivers. obstructs the development of radio -beacon frequency band: (upper) the present paris Many small -craft receivers the art. For example, although Plan arrangement showing the modulating side-tones are hand -held. They include a it is now possible to measure (lower), the new Geneva Plan narrow channels. In built -in ferrite -rod aerial, a and record the bearing errors both cases the sidebands of the Morse transmissions meter or headhones to show the 'due to the ship's structure and are omitted. signal null as the receiver is rotated and a magnetic corn- pass to measure the bearing of the beacon when the null has been found. A hand -held receiver appears deceptively Fig. 4. Transmission simple; in fact it contains a fre- sequence of a group of six quency synthesizer for channel radio-beacons. selection and a precise clock to Transmissions start on identify the transmission time - each minute of the clock slots, since the most users can- and are identified by not read the Morse code identifi- callsigns transmitted in cation. Morse code. ELECTRONICS & WIRELESS WORLD MAY 1986 19

www.americanradiohistory.com Acknowledgements to apply corrections auto- sions are compatible with the transmissions are not essential The author acknowledges the advice of matically, the Paris Plan re- old receivers, even though the to high -tech. receivers, their Mr F.E.J. Holden of Trinity House Lighthouse Service and Mr W. quires the errors to be plotted channels have been packed so great value is in providing rapid Paterson of the Northern Lighthouse and corrections applied by the much more tightly together. and immediate access to up -to- Board in the preparation of this article. operator! Most small -craft receivers date information. Navigators These criticisms of the pre- References already have very narrow band- are supposed to note and record 1. 'Final Acts of the Regional sent system - together with a widths, since they require only all changes of radio -beacon Administrative Radio Conference for call for much greater automa- the carrier for direction -finding. parameters - a tedious task. the Planning of the Maritime tion of receivers - have led to The Geneva Plan protects the Because the data transmissions Radionavigation Service (Radiobeacons) new radio- beacon transmission older Convention ship receivers will make this process more in the European Maritime Area', International Telecommunications standards being agreed: in which have wider passbands by certain - and safer - several Union, Geneva, 1985. April 1992 the Geneva Plan of not allocating adjacent channels administrations, including the 2. Paterson, W., 'Proposed changes 1985 will replace the Paris Plan to beacons in adjacent areas. So UK, are planning to introduce to maritime radiobeacons'. Paper 6.6.1, of 1951. the existing receivers should them as soon as the Geneva Conf. of the International Association of Lighthouse Authorities, Brighton, The new Geneva plan totally take the changes in their stride Plan comes into force. 1985. abandons the use of modulating and no -one is forced to buy a The short transmissions with 3. Barratt, J., 'Automated direction tones. The resulting narrow- new receiver. their data signals will lead to a finder', Wireless World, p57 -60, 1982. band transmissions can be spac- The 'revolution' is in the major advance in radio direc- 4. Bozic, S.M., 'Digital and Kalman filtering', Edward Arnold, London ed by only 500Hz, so creating short transmissions, shown in tion finding, but the possi- 1979. 62 channels, in place of the Fig. 5, which are radiated at bilities start to get really in- 5. 'Le système RANA p17 - extrait previous 14, in a slightly - one -minute intervals and allow teresting when one thinks of de la documentation technique', Service expanded band (bottom of a new generation of 'high- tech', putting a processor in control of des Phares et Balises, Paris, 1979 (in French). Fig. 3). Although these are suf- automatic, processor -controlled the tuning of the receiver - so ficient channels to do away with receivers to be developed. creating a scanning receiver the grouping of beacons and Beacons which are grouped in which can step through the allow every beacon to operate threes will each transmit rapid- beacon frequencies. When first continuusly without mutual in- ly in turn so that these high - switched on, the receiver would terference, some national ad- tech receivers can take and have no idea of its position. It ministrations will continue to store sets of bearings with would locate itself by scanning group many of their beacons. negligible skew errors at one - through the radio -beacon chan- They argue that navigators find minute intervals. nels for a period of three it more convenient to receive But the short transmissions minutes, building up a record of beacons in the same area on a contain provision for something the strengths and signal -to- common frequency. In no case, more: the identity, latitude and noise ratios of all the signals however, will there be more longitude of the beacon received. The strongest than three beacons to a group. transmitted in digital form. Us- transmissions would then be At first glance, the transmis- ing this information, together identified either by receiving Fig. 5. Under the new sion sequence in Fig. 5 looks with the measured bearings, their data transmissions or by

Plan, some radio -beacons remarkably little altered: the the receivers will compute the comparing the frequencies . and will be in groups of three, long transmissions have been ship's position and show it in time -slots of the transmissions although many will retained - though slightly digital form or even on a mov- with radio -beacon data stored transmit continuously on shortened - for the use of ing map display. The data in the receiver. The bearings of individual frequencies. hand -held receivers. The transmissions will use narrow - these beacons and the ship's The Morse transmissions Morse code identification is still band frequency -shift keying - heading would also be are retained and short there too, but the carrier is either conventional f.s.k. at 100 measured. Then, using all this data transmissions are keyed instead of the modula- baud, + / -85Hz shift (similar to data, the processor would introduced at one-minute tion. This means that receivers the marine telex system) or calculate the ship's position, intervals. New `high -tech' must havé beat -frequency minimum shift keying (m.s.k.) taking into account not just the direction- finders will use oscillators (b.f.os) but most at 40 baud. The choice between bearings of two beacons but these to measure bearings already have them to receive f.s.k. and m.s.k. will be made weighting the contributions of and read the beacons' certain (A1A) aeronautical by a World Administrative all nearby beacons in accor- identities, locations and radio -beacons. Radio Conference in 1987. dance with their signal -to -noise ranges. In fact, the new transmis- Although these data ratios. The information about each beacon which is transmitted or stored will also contain its 'protected range' - the area within which the Geneva Plan ensures that its signal is at least 15dB stronger than that of any other beacon which shares its channel. This information will allow the processor to check that the ship is within the protected ranges of the beacons it uses to calculate its position. Once the receiver has obtained an initial fix, it continues to track the vessel, displaying its position continuously. The simplest receivers would recalculate position coordinates 20 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com each time a was still use d /f. FEEDBACK bearing measured. Cleverer receivers Part of the reason is that, would use a Kalman filter' to while Decca and LORAN -C are unavoidably present the expensive model the dynamics of the ship, only available in parts of the BLACK BOXES image that turns a lot of potential enthusiasts away from the hobby. modifying and displaying the world (not by any means in all The magic of amateur radio still So there is a need for as much of position estimates continuously Europe), while present exists and, in some ways, with exposure of el cheapo amateur on a moving map display. Posi- satellites give quite infrequent greater power, despite the radio as possible, such as tion inputs from other naviga- position fixes with significant proliferation of black boxes. High construction information, QRP and tion receivers could be combin- errors due to the vessel's move- equipment costs do present SWLing. ed to give an integrated naviga- ment and NAVSTAR is subject problems to newcomers to the Public interest can be roused. tion system. to delays and fiscal cut -backs, hobby and to the image amateur Try featuring Morse code So the new transmission stan- radio -beacons are available in radio presents to the public. communication at your club's next dards make possible the both advanced and developing Outsiders look upon amateur appearance at the local hobbies expensive CB' and exhibition or rally. You'll be development of revolutionary countries. They are operated in radio as 'more turn away. People generally are amazed how the public associates direction- finding receivers each state by local administra- unimpressed with communications old up -down key technology with which operate wholly tions, not by overseas govern- technology: crystal -clear colour tv 'real radio'. A microprocessor c.w. automatically, providing the ment agencies or companies; coverage of cricket in Australia or decoder and v.d.u. make the navigator with a continuous their technology is simple and the latest pictures from Uranus interest even greater. view of his position. No such operating costs low. are taken for granted. The future of amateur radio receivers exist, of course, and it One or two possible glimpses There is nothing wrong with depends upon us making the most is sensible to question when - of the future have been given radio amateurs using black boxes, of new technology and keeping or even whether they will be by the French, who have sug- however expensive. Japanese alive vital interest in the basics of - release and that radio -beacons will equipment manufacturers radio, communication appear. To create such gested new models every year and people electronics. receivers requires no technique not so much die as be metamor- buy them. It must be fun being Denzil S. Roden, G3KXF is not already known and phosed into something new. wealthy! As far back as I can Sompting understood nor any which is For some years certain French remember, big powerful stations Lancing especially expensive - as ever radio -beacons have transmitted have existed in places such as West Sussex in electronics, the greater the 'differential Omega' data. Kilowatt Alley, but the casual role of the processor, the lower Omega is a world -wide, v.l.f. listener is not to know how those the production cost. The most hyperbolic navigation aid. operators are qualified to run I YES advanced direction -finders Because of periodical changes expensive equipment. know that MINISTER many them have started on the in ionosphere, Omega of already compute positions the factory floor, worked their way up The letter from David Rudd of the automatically, using beacon receivers experience position through all aspects of electronics Department of Transport (March data typed in by the operator errors which are substantially design and manufacture, to retire 1986) well illustrates the who must also specify the constant over large areas. So as multi -national company capabilities of innovation and beacons to be used. The new the errors measured at fixed directors. They are entitled to originality that our public servants transmissions simply remove stations on land are broadcast enjoy the amateur radio they can have. The abdication of planned the restrictions on the further as 'differential Omega correc- afford. and responsible spectrum allocation in favour of the development of such receivers, tions' and used to correct the We have to accept that black discredited monetarism of his of in boxes are and ever will be an providing automatic input of fixes marine receivers the current masters is a perfect The Coast established part of amateur radio. beacon data, automatic selec- same area. US Thanks to new technology and though late demonstration of the tion of beacons and easier Guard are likewise proposing to manufacturing techniques, supine theorising to which our identification. use radio -beacons to broadcast equipment now represents far country is subject. If there is no technical differential data to improve the greater value per pound earned If, as he alleges, the spectrum is obstacle to the development of accuracy of fixes made using than in the 1950s. But there is a abused by vandals, selfish, large, these high -tech receivers, will the proposed NAVSTAR very great deal that experienced and obdurate, using outdated their development be plain sail- (GPS). amateurs can do to portray the techniques and unsuitable frequencies, is it not the fault of ing? Pessimists would say not In addition, the French have existence of the low cost approach our public servants? Are the developed and installed a to our hobby. - pointing to the falling costs These days, beginners come into established bully -boy users to be and ready availability of small - hyperbolic radio navigation amateur radio 'backwards', confirmed in their place by the boat receivers for the hyper- system - RANA - operating starting with v. or u.h.f. f.m. with size of their purse? Do the "small bolic navigation systems in the radio -beacon frequency zero interference and no `need' for latecomers" have bigger purses? If (several for Decca Navigator bands and IALA are studying internationally recognised there are bad practices, stop them. alone), the rapidly growing use the possibility of precisely syn- operating procedures, then In this regulation -ridden society I of satellite receivers and the chronising the carriers of progress into h.f. and wonder am sure that suitable regulations of date, I promise of NAVSTAR. "D /f ", groups of beacons to form what hit them! The B licence exist. If they too are out in forcing one to would be happy to offer my they say, "is dead "! hyperbolic systems. These causes problems is difficult services, but to pretend that could be not only start at v.h.f., where it But d/f has been a -dying for beacons used to home brew gear, so one is spectrum renting will solve abuses years and, while doing so, mad- for good old- fashioned compelled to buy. It might be generated by managerial deningly continues to grow! direction -finding but better to have beginners deficiencies is an arrogance. There are now more radio - simultaneously for precise introduced directly into h.f. where Another arrogance is the beacons and more receivers hyperbolic navigation to ac- a valve oscillator /p.a. transmitter pretence that the present secret than ever before. It has been curacies of a few metres! is within everyone's reach. practices of allocation would estimated by the International Whether that will happen or The formative years of pre - somehow be ended by the transfer it not possible for not I do not know. But I suggest licence short-wave listening are of money. Is Association of Lighthouse display their that the next few years will missing, so there is a great need administrators to Authorities (IALA) that for magazine articles, club lectures competence in public? The in its throughout Europe, a quarter of prove interesting and that, and shack visits, to fill the gaps in dissemination of claptrap through a million people depend on 'death throes', radio direction - the amateur radio education the media of papers, lectures, direction -finding as their finding will make far more process. Dealers need to advertise letters etc. still leaves it as primary means of radio naviga- waves than many suspect. their black boxes in order to make claptrap; it cannot be mistaken for tion, whilst some 57% of Con- a living: consequently magazines, a display that would bring any vention ships report that they including the RSGB Radcom, credit to the propagator. ELECTRONICS & WIRELESS WORLD MAY 1986 21

www.americanradiohistory.com FEEDBACK

I will always be indebted to the departments, if there are any left another. The basis of the RISC peripherals that we need a Department of Transport for to do this work after current principle is the building of fast revolution - not in c.p.us. defining "arcane" for me, but now government cuts. Hopefully we machines by limiting the Historically, peripherals have they have no buses to run could may also see a capacitor model instruction set to instructions and always been the performance they leave the spectrum alone? It produced from measurements addressing modes that can be limiters, especially when one may well need attention but surely down to microvolt and nanoamp executed without appreciable considers total program run -time not from them. levels, which will predict non - microcode, while providing a partl3 rather than c.p.u. execution time. D. E. Kershaw linearities of an audible exposed microarchitecture that Anybody who doubts this should Marton proportion. provides good hooks for complex reply honestly to one simple Blackpool Mr Self knows of no mechanism operations. RISC machines question; last time your driving Lancashire whereby a sinewave can be left typically employ numerous licence was updated, how long did intact and yet music 'mangled'. registers to speed context it take? There exists a phenomenon called switching but this is not essential. Martin Bacon ELECTROLYTICS phase distortion which can be of The Pyramid superminicomputer Taunton such a magnitude as to render and the new Acorn ARM processor Somerset AND DISTORTION speech unintelligible after are members of the species; the transmission over, for example, TMS32010 DSP uses RISC I have read with interest, in long unloaded telephone lines. techniques to such effect that its CLASS B OUTPUT February 1986E&WW, letters This is quite a serious distortion execution speed is comparable from White and Self, on the when one considers that speech, with bit -slice designs. RISC There would seem to be very few subject of electronic components when infinitely clipped is still machines do not avoid the Von new circuits under the sun. A affecting the subjective sound intelligible. Furthermore a linear Neumann bottleneck, however; in circuit similar is that described by quality of audio amplifiers. low -pass filter, at say 100Hz, will fact they may actually worsen it in Mr Nalty in 'Circuit Ideas' White seems to sit on the fence not produce any harmonic one respect. Microcoded (February 1986) was previously and invoke a whole host of distortion but can be said to processors typically do not use the published by Mr Edwins in Hi Fi variables along the record/replay mangle music considerably. buses with great efficiency (in fact News and Record Review, October chain to explain perceived From my present (unconfirmed) the old 6502/6800 designs leave 1971. This circuit differed only in differences in the final sound observations (a) aluminium the bus dead for half the memory detail from that submitted by Mr quality. Self uses a very strange electrolytics are the worst cycle time.) It is thus possible to Nalty; in the Edwins circuit three logic to 'prove', that because his sounding capacitors commonly have multiple processors sharing diodes were used to generate the and others' tests on capacitors available, and (b) back -to -back one set of utilities. A RISC bias voltage. show only limited deviations from aluminium electrolytics (which machine with highly efficient bus Having built one of these the ideal, then somehow they incidentally will not cyclically utilisation cannot share the bus circuits some ten or twelve years cannot affect sound quality. Self depolarise) are little, if any, better. without having to wait for program ago, and used it ever since, I argues that the proponents of B. Powell and data. would state that the quality of 'better capacitors' have dreamt up Crimson Elektrik If I may suggest a slightly sound it helps produce is "new effects ", which Self argues Stoke -on -Trent different analogy, the new significantly superior to the cannot exist without "a theoretical generation of 32 bit c.p.us traditional class B circuit. When mechanism for the operation of resemble Rolls -Royces and the first built the circuit was the effect that is logically VON NEUMANN RISC processors resemble racing extensively tested for distortion consistent if not actually I was somewhat disappointed by motorcycles. (The Intel 386, with both at high and low signal levels. plausible ". the January article (p.6) "Von an enormous array of bells and The only conclusion reached was Does Mr Self genuinely believe Neumann's elephants." There are whistles, perhaps more closely that better measurement that an implausible theoretical several statements with which I resembles one of those Cadillacs equipment was required, as it was mechanism is of any value in would take issue. Computable modified for desert oil sheiks, but discovered that what was being furthering the present state of Numbers is certainly a landmark this is getting rather silly.) I measured was the 'distortion' development of audio amplifiers? paper in the history of numerical suspect choice is largely a matter output of the oscillator. The In the real world, a great many methods. However, modern of market forces or personal equipment used was manufactured well liked and widely sold computers did not start to appear preference. The Transputer is by Radford and was of a very high amplifiers, make extensive use of until some years later. apparently a way out of the standard - type numbers have non -aluminium electrolytic The machine described in bottleneck - it has serial links been forgotten. capacitors. Aluminium electrolytic Turing's paper does not have a between processors to relieve the R. T. Wrigley capacitors are certainly the Von Neumann architecture. The bus overhead problem - but Ware cheapest; hopefully manufacturers program quite clearly resides in the consideration shows that some Hertfordshire that use non -aluminium ones have "head" in the form of time must be consumed in a good reason for doing so. "configurations ", which interprocessor communication. No Amplifier manufacturers tend to approximate to the routines being doubt Inmos have looked very hard MATHS PUSHERS make more sales and therefore executed at any moment. at the trade off between parallel processing costs and sophisticated profit, when their amplifiers sound Furthermore (though I am open I feel that Ivor Catt is aiming at better than their competitors and I to correction on this) I believe that memory architectures for processor -to- processor -messaging, the wrong target with his polemic, think Mr Self should give the machines on which Von in recent issues, against credence to this fact and examine Neumann actually worked did not but my own feeling is that the Transputer architecture has as its mathematics and mathematicians. its implications. have subroutine capability, being I would like to take one example, Familiarity with a range of effectively large calculators. There major virtue the ease of connecting multiple processors rather than the a topic which he has touched on presently available amplifiers is a case to be made for all modern several times over the years in reveals that non -aluminium computers being derived from the avoidance of bus limitations. One of the worst bottlenecks in WW: the use of Fourier series. electrolytics are prevalent in very Babbage architecture and the Mr Catt has held up to scorn the low level circuitry, in direct machines designed and worked on computing is the backing store. The problem is that where assertion of a certain FRS that contradiction to Mr Self's by Turing and others after 1945. "reality is made up of sine implausible depolarisation theory Turing's major claim to fame, I numerous users share a large data base, any modification made by waves ", and has pointed out that which predicts quasi -perfect submit, is the profoundly practical Fourier expansions are no more behaviour from aluminium types nature of his genius, and the fact one must reach all. Reductions in the cost of semiconductor memory than a computational tool, at these tiny signal levels. that (unlike other mathematicians) sometimes useful and sometimes I agree that these subjective he was prepared to teach himself do not necessarily help this problem since the ability to store not. It is mere fantasy to suppose observations should be confirmed the electronic engineering he that the description of a single by suitable tests and statistical needed to make his prosposals very large amounts of data in ram transfers the bottlenecks from disc square pulse as a continuous analysis but I suggest that concrete. spectrum of sine waves has a manufacturers have little to gain RISC computers are one thing, to ram without changing its nature. My own pessimistic conclusion is better claim to reality than the from this. It can be more properly and the data -driven architectures itself. Fantasy that it is the field of mass storage pulse becomes explored in university research alluded to in the article are quite absurdity when one contemplates 22 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com the action on such a pulse of a it is useful to define the skin depth publication, these had not yet been principles or axioms, accepted by perfect low -pass filter (which is as the depth at which the discovered. everyone as being obvious defined by what it does to sine magnitude of the field has dropped It seems that Maxwell's truisms, unprovable and waves): its output must begin to 1/2 or exp( 1) of its surface equations are beautiful examples fundamental. Thus any sort of before the leading edge of the value. The current is not confined of the so- called scientific method, "truth "derived from a set of pulse arrives. to a surface region as Mr Fant whereby a large and diverse group axioms can only be relative and All this is true. But is it the fault perhaps thinks, and the skin depth of natural phenomena observed confined with respect to the of mathematicians? Around ten is not a magic depth below which experimentally can be explained framework of the axioms from years ago I was studying pure current cannot penetrate. within the framework of a unified which it was derived. Change one mathematics at Edinburgh At high frequencies, the skin theory, which is even capable of of the axioms and you end up with University. I recall that in the depth is indeed small -a few predicting future discoveries. an entirely different serof course on partial differential micrometres at v.h.f., but even at Maxwell's equations make "truths ". (This actually happened equations, the lecturer pointed out 50Hz the skin depth is only about statements of obvious truisms to one of Euclid's postulates which (as Mr Catt has done in your a centimetre. There is no point, much like Euclid's postulates from gave rise to a new kind of columns) that the most general then, in making power cables which a lot less obvious truisms geometry.) In fact, you can invent solution of the wave equation: more than a few centimetres in were later derived, much to the any set of axioms you wish and a2u = 82u diameter, as the central portion surprise of everyone. However, derive any "truths" from them ax2 at2 would not carry much current. I Euclid's postulates were not the you wish. These, however, am led to believe that this is why last word in geometry, much as become scientific truths only is u= f(x +t) + g(x t), for the cables on overhead Maxwell's equations were not the whenever verified by experiments, arbitrary (sufficiently transmission lines are often last word in electromagnetic providing that somehow they differentiable) functions f and g, bunched as a group of four small theory. relate to our real world (another and not, as is sometimes cables rather than one larger one. Catt's rather extertaining bad choice of words). In fact, Mr supposed, some complicated David Gibson equations presented by him as a Catt's funny equations teach us are Fourier series. Who, then, Broadstone parody of those of Maxwell, might just that. these people who believe that Dorset still turn out to be great I. Shaw "reality is made of sine waves "? I milestones in science, should they Pretoria went to the library of the somehow become recognized as a Republic of South Africa work, university where I currently MAXWELL'S theoretical framework for a large and looked at a random selection group of phenomena observed of books on p.d.es on the empirically. mathematics shelves. All of them EQUATIONS XY PLOTTER I would like to present a modest solution, and gave the general contribution of my own, most plotter those books which treated Fourier Maxwell's equations are merely In the excellent `X.Y. more formulations humbly called Shaw's theorem. To article in December 1984, expansions at all did so only at a precise of the update' conserve space, illustrations will P.N.C. Hill, the formulae much later point. Then I looked following phenomena, verifiable by author be dispensed with. In a recent of the on the shelves for physics and experiment: printed for the calculation 1. in scientific experiment. I placed an to in Out of ten books, Changes the spatial best next step take the engineering. apple on the table, and a few correct general distribution of an electric field are plotting of a 'straight line' (at the only two gave the minutes later, another apple was The remainder all dove attributable to a magnetic field bottom of page 77) requires, on solution. also placed thereon. This straight into separation of which changes as a function of most computers the use of experimental fact may be variables, superposition and time. 'floating point' routines, which of expressed in the following Fourier transforms, and never 2. Changes in the spatial course tend to be relatively slow magnetic field are mindboggling mathematical mentioned the general solution at distribution of a and not directly amenable to field jargon: all. It seems that physicists and attributable to an electric translating into a machine code a +a =2a engineers do not suffer from too which changes as a function of program. This, of course, only much mathematics, but too little, time. represents A rework of the formulae is an obvious truism, since it is only and too little understood. Maxwell's equations merely shown below: it now requires for Richard Kennaway state the empirically observed a symbolic expression of the facts its solution only the use of simple School of Information phenomena described above in the observable in my experiment. integer additions, and can be Systems "shorthand" notation of vector (The astute reader might even coded up with no great difficulty University of East Anglia analysis, a particular branch of predict, as an inevitable outcome (my own Z80 -based home -built Norwich mathematics which lends itself of my revolutionary discovery, plotter uses this method). very nicely to the expression of that if the symbol a means a It is written in program form as spatial and temporal changes in a banana, the equation would still be the computer's own screen can symbolic form and thereby avoid valid! But let us leave such demonstrate the line draw. ENERGY the cumbersome and imprecise discoveries to posterity ... before 10 INPUT "LINE FINISH sentences written above. Mr Catt would hastily remind us POINT (X) "; XF TRANSFER In my opinion, Maxwell's great that the above equation does not 20 INPUT "LINE FINISH There is no problem with electric contribution lies not in any teach us anything about fruit ...) POINT (Y) "; YF current theory as questioned by inherent truth or mystical quality It seems to be fashionable today 30 B= XF Mr Fant (Letters, March 1986). (not to mention "obvious truism ") to say that scientific theories are 40 C =YF The resistance of a wire is attributable to the equations nothing but tautologies and 50 F =0 inversely proportional to cross - themselves but in the manner in obvious truisms, purposely 60 IF F =1 THEN A =A +YF: sectional area at zero frequency which it made possible the obscured by mathematical jargon. C =C +YF (d.c.). Without getting bogged derivation of a unified theory that In defence of the mathematical 70 IF F =2 THEN D =D +XF: down in EM theory (Theory M. explained diverse phenomena jargon, I wish to say that motion B =B +XF Theory H and Ivor Catt's Theory manifested in Faraday's and change in time and space will, 80 IF ABS(A B) < ABS(C D) CO it is broadly true to say that a experiments covering a broad field if expressed in mathematical THEN 90: ELSE 100 time -varying EM field cannot exist known today as electrostatics, "shorthand" notation, necessarily 90 Y =Y +1: PLOT X, inside a perfect conductor and that electric circuit and network theory involve "a mixture of integrals, Y:F =2:GOTO 60 when it penetrates a good, but not (both lumped constant and divs, curls" called "headspinning 100 X= X +1:PLOT perfect conductor, its magnitude distributed parameter versions), brew" by those who never X,Y:F =1:GOTO 60 drops off as the depth increases. A skin effect, antennae, wave understood their function as The program is shown only good analogy is that it is 'seeping' propagation, etc. from just two merely shorthand symbols, easily working in the first quadrant, lines into the conductor, and the rate of basic equations stating "obvious manipulated and visualized by 90 and 100 being altered to suit seepage depends on the truisms ". As a matter of fact, means of simple rules even by the machine in use. conductivity and the frequency. Maxwell's equations actually first-year university students. As J. Jardine The skin depth is a convenient predicted the existence and to tautologies and obvious truisms, Dewsbury measure of this rate of seepage. behaviour of radio and microwaves logical thinking is a process which Yorkshire Since the drop off is exponential, since, at the time of their needs to start from a set of first ELECTRONICS & WIRELESS WORLD MAY 1986 23

www.americanradiohistory.com by R.F. Coates 68000 board - 6 Bob Coates ends his description of the monitor software with details of some applications

To illustrate some of the techniques we have discussed, we will now look at some LOC OBJECT M STAT E LINE SOURCE LINE simple programming examples. \V L shall touch briefly on accessing the duart 1 + and p.i.t. but these devices are very complex 2 + example 1 and 3 + Demonstrates using breakpoints and the trace function it is beyond the scope of this series to deal with 4 + them in any depth. Interested users should 5 Lab asect rom 000000 6 org h'400400' therefore obtain the Motorola data manuals. 7+ These are fairly voluminous documents! The 400400 7000 1 8 moveq #0,d0 e clear 'd0' 400402 72(0 2 9 moveq 80,d1 data manuals will be obtainable from Magenta 400404 20700000 3 10 movea.l $h'100',a0 + set 'a0' to $100 Electronics, who are producing a package 0100 consisting of manuals for the processor and for 11 e 40040A 5280 4 12 loop addq.l 81,d0 a increment 'd0' the duart and p.i.t. 40040C 0601000A 5 13 addi.b 1110,d1 + add 10 to 'd1' (byte operation only) When using Kaycomp with only a terminal 400410 5588 6 14 subq.l *2,a0 + subtract 2 from a0 15 e and with no access to a 68000 assembler, it is 400412 60F6 7 16 bra Loop and Loop for ever feasible to assemble by hand but it is a some- 17 e what laborious task. This problem will be solved 400414 18 end by the introduction of the eprom -based assembler for the board. Other recommended reading is `68000 Assembly Language Programming' by Kane, Hawkins and Leventhal, published by Os- borne/McGraw -Hill. The necessary information

LOC OBJECT M STAT E LINE SOURCE LINE to hand -assemble is available from this, the MC68000 User's Manual and the MC68000 Pro- 1 + gramming Card from Motorola. 2 IF example 2

3 + Demonstrates hou system calls are used and how ' pdatam' call In the examples which follow, the listings 4 e selects display format according to column mode set. 5e were produced by an assembler which uses a dif- 6 renter equ 0 e call number of 'renter' ferent convention for denoting hex constants 7 pdatam equ 6 e call number of 'pdatam' from Motorola's, h '1F' being equivalent to $1F 8+ 9 lab asect rom etc. The assembler directives are also different, 000000 10 org h'400430' but should be self -explanatory. 11 e The examples start at address 40040016 which 400430 40FA000A 1 12 Lea string,a6 + Load 'a6' with address of 'string' 13 e is the lowest ram address that the user may use; 400434 4E48 2 14 trap #11 40000016 to 4003FF16 are reserved for use by the 400436 0006 15 data 0,pdatam e call 'Mates' 16 + monitor. 400438 4E48 3 17 trap III 40043A 0000 18 data 0,renter e return to monitor 19 e 20 string equ $ Example 1 40043C 48656C6C 21 data 'Hello from "KAYCOMP ". This example is 6F206672 A very simple example is sufficient to demon- 6F6D2022 strate the trace function and the use of break- 48415943 4F4D5022 points when running a program. Using the MO 2E205468 command, enter the object code, which is the 69732065 second of 78616070 column the listing, into memory at the 6C652069 address shown in column 1. 7320 The first three lines of the program preset 400462 8086 22 data h'8d',h'8a' d1 400464 746F2064 23 data 'to demonstrate "PDATM".' three of the processor's registers, do, and ao 656D6F6E with 0, 0 and 10016 respectively. The loop sec- 73747261 tion of the program then adds 1 to do, 10 to dl 74652022 50444154 and subtracts 2 from aD. 4140222E First try putting a breakpoint at address 40047C 0006 24 data h'Od',h'Oa' 40047E 4279652D 25 data 'Bye -Bye' 40040A. Now run the program using GO 427965 400400. 400485 00 26 data 0 The registers should now be displayed with 27 + 28 their preset values as the breakpoint has been 400486 29 end hit. Next set another breakpoint at 400412. This must be a different breakpoint number from the ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com previous one, as we shall continue from the pre- LOC OBJECT M STAT E LINE SOURCE LINE vious break. 1 * When we use the CN command, it looks to see 2 e example 3 which breakpoint was encountered and starts 3 * from there; so it must not be moved in the 4 * Gives a simple example of accessing the MC68230 PUT 5 it sets Port A as all outputs, then puts 'h'55' and 'Oxaa' a Lternatety meantime. CN will restart the program, cancel- 6 * on the Port, with a pause between each change ling the first breakpoint and displaying the regi- 7* of pi /t 8 pit equ h'a00001' ! Base address it the next one. Here from base sters again as encounters 9 pacr equ h'c' ! Port A control register offset A register offset we should see that the registers have been 10 paddr equ h'4' ! Port data direction register offset altered by the appropriate amount. 11 padr equ h'10' ' Port A data 12 The operation may be seen more clearly if the 13 Lab asect rom trace function is used. Remove the breakpoint at 000000 14 org h'400490' 15 f 400412 by setting the address of that breakpoint PI 400490 207C00A0 1 16 movea.L tpit,a0 ! set 'a0' with /T base address to 0 using Bn. Now start the program using TR. 0001 0, Enter 400400 for both trace and program 400496 117C0000 2 17 move.b t0,pacr(a0) ! set mode submode 00 000C start. Registers should now be continuously dis- 40049C 117COOFF J 18 move.b *h' ff',paddria0) ! set Port A as all outputs played after each instruction is executed. Execu- 0004 tion can be suspended by control -S. 19 400442 117C0055 4 20 Loop move.b th'55',padr(a0) ! set Port A to '01010101' Leave it running for a while and see what hap- 0010 pens to d1. The add instruction on this register is 400448 610A 5 21 bsr.s delay 4004AA 117COOAA 6 22 move.b *h'aa ,padr(a0) ! and now to '10101010' byte -length only so it will be seen that when the 0010 count passes FF it wraps around to 00. The 400480 6102 7 23 bsr.s delay 400482 60EE 8 24 bra Loop ' and do forever upper six digits always remain unchanged. 25+ 400484 2030000F n 26 delay moved t1000000,d0 4240 27 i

Example 2 40048A 5380 10 28 deLayl subg.l t140 ' Loop round killing time 40048C 66FC 11 29 bne deLayl Our second example illustrates monitor calls and 30 how the 40/80 column formatting may be used. 40048E 4E75 12 31 rts The lea instruction loads a6 with the address of the start of the string. Then pdatam is called 4004C0 end with the two lines . . . LOC OBJECT M STAT E LINE SOURCE LINE trap # 11

data 0, pdatam I * Example 4 The word data is an assembler directive which 2* 3 e Demonstrates how to talk directLy to the DUART and hou user vectored

means 'form a byte containing the value of 0 and 4 * interrupts are handled on 'Naycomp' pdatam'; pdatam is equated to 6, so the assem- 5 * The DUART is connected to IPL1 giving a level 2 interrupt value. 6* bler inserts this 7 duart equ h'800001' * base address of DUART After printing the string, which is terminated 8 imr equ h"a' offset from base of interrupt mask reg. by the null byte, the next trap instruction causes 9 ivr equ h'18" * " " " interrupt vector reg. 10 trba equ 6 tx /rx buffer reg. A a return to the monitor. 11 isr equ h'a' f interrupt status reg. . Try first running this program with the 12 cra equ 4 f command reg. A mode at 80, then at 40. You will see that 13 f column 14 Lab asect rom in the 40- column mode an extra new line is inser- 000000 15 org h'4004c0' ted after the word 'is'. This is due to the data 16 400400 2C7C0080 1 17 movea.l #duart,a6 point 'a6' at base of DUART line h '8d', h '8a' which are the Ascii codes for 0001 carriage- return and line-feed with bit 7 set to 1. 18 * of pdatam explains the dif- 4004C6 1D7C0040 2 19 move.b 4164,i'r(a6) put vector t64 in int. vector reg. The description 0018 ference. 20 21 * put first the 'JMP.L' opcode and then the absolute address of exception 22 f handling routine in vector t64 RAM jump Location 23 opcode Example 3 4004CC 33FC4EF9 3 24 - move th'4ef9',h'400082'.l * 'JMP.L' 00400082 The MC68230 peripheral interface /timer i.c. is 400404 23FC0040 4 25 moved texcep,h'400084'.l * address of exception handling routine will 04EA0040 not used by the monitor, so this example 0084 check whether the device is working or not (if 26 f fitted). 40040E 1D7C0002 5 27 move.b t2,imrla6) a unmask interrupts for char. received 000A The base address of the p.i.t. is h 'A00001' 4004E4 027CF9FF 6 28 andi th' /9/ /',sr f set proc. int. mask to Level 1 and the first line sets a0 to this value. All refer- 29 * 'regi- 4004E8 60FE 7 30 hangup bra hangup * hang up in loop here, exit when exception calls ences to the p.i.t. are then made using the 31 ster indirect with offset' addressing mode. The 32 f User Interrupt Vector t64 handling routine three registers of the device we are going to 33 a Executed when character received, gets it and prints hex equivalent of 34 f ASCII character access are equated to their offset from the base 35 f address of the device. 4004EA 102E0006 8 36 excep move.b trba(a6),d0 * get character in 'd0' line the mode of operation of 4004EE 4E48 9 37 trap #11 The next sets up 4004F0 0009 38 data 0,9 caLL 'out2hx' to print it as tuo characters the p.i.t. (refer to the manual) and line after sets 4004F2 4E48 10 39 trap t11 the data direction register for port A of the 4004F4 0003 40 data 0,3 f and add a 'space' 41 f

68230 to all eight lines as outputs. 4004F6 1D7C0024 11 42 move.b th'24',crala6) f reset receiver Then the program enters a loop where the 0004 A are set alternately to 01010101 4004FC 10700005 12 43 move.b 115,crala6> * and re-enable port outputs 0004 and 10101010 with a delay in between. This 400502 4E73 13 44 rte * return from exception delay is about one second with a 10MHz clock 45 f and pro -rata for other clock frequencies. On 400504 46 end ELECTRONICS & WIRELESS WORLD MAY 1986 25

www.americanradiohistory.com Supplies for this project are looking on the port A pins on P5 with a 'scope, the processor's interrupt mask is set to level 1 - available from Magenta logic probe or even a Electronics, 135 Hunter Street, voltmeter, you should see one lower than the level of the interrupt gener- Burton -on- Trent, Staffordshire each output toggling. ated by ILP 1. DE14 2ST. The p.c.b. alone The program then hangs up in a loop waiting costs £ 18.90; with eproms and for an interrupt. monitor, £41.78; with assembler' also, £58.38. Prices include Example 4 This may seem a little pointless (in practice the processor would v.a.t., but please add 60p for Now on to the interrupts. The interrupt output be off somewhere doing postage. something of the duart goes to the processor useful), but it serves to demonstrate IPL1 input, the principle. the one on the Kaycomp wired for user -vectored An interrupt will be generated when a ter- interrupts. Accesses to the duart are made in a minal key is pressed and processing will jump to similar manner as in example 3 using 'register vector # 64 location indirect with offset' addressing. where it will find the ram address h '400082'. First the user interrupt vector number we are There it will execute the h going to use, 64, is put into the interrupt vector jmp.l '4004EA' instruction which is the start of the register (i.v.r.) of the duart. This value is exception passed processing routine. over the data bus during the interrupt acknow- This first gets the character from the transmit /receive ledge cycle to tell the processor which vector buffer register (trba) of port A of the duart. The 'trap # 11, 0009' call address to fetch. If the register is not set, it prints the two -character hex equivalent holds a default vector which points at the of the 'uninitialised interrupt vector'. Ascii key; the next trap instruction adds a space Later, after them. try padding out this line with NOPs and The see what happens, duart receiver is then reset and re- but operate 'reset' before enabled, running it. because the previous monitor calls (which were not designed Next in the to be used at the same program, the jmp.1 instruction op- time as code duart interrupts) upset the receiver and the address of the service routine are operation. placed # in the vector 64 ram block at h The '400082'. 'return from exception' instruction then causes processing to return to the next Finally, interrupts are in instruc- enabled the duart for tion after characters received where it left off, the 'hang -up' loop (refer to duart manual) and again, until the next interrupt.

LOC OBJECT M STAT E LIME SOURCE LINE Example 5

1 e This example shows one way of accessing a peri- 2 example 5 3e pheral on the G64 bus. 4 * Demonstrates using a 664 peripheral card and handling autovectored interrupts The card I have chosen is the Syntel SYN- 5 in this case the G64 -IRO, which goes to the processor IPLO. 6e ADC2 which is an analogue i/o card having eight 7 base equ h'fff801' e base address of ADC2 card 12 -bit analogue inputs and two 12 -bit analogue 8 adc equ 8 e offset from base of a-d read address outputs. It is unlikely that many readers will 9 ddc equ h'c' e " " digital data channel 10 e have this card, but I include the example to illus- 11 Lab asect rom trate the principles of external bus access and 000000 12 org h'400510' handling auto -vectored interrupts. 13 e

400510 33FC4EF9 1 14 move 8h'4ef9',h'400016'.L e put 'JMP.L' The card must be configured as follows: code in autovector 1 00400016 Address switches - all on (FFF80116, bottom of 400518 23F00040 2 15 moved texcep,h'400018'.L e and abs. addr. of handler routine 053E0040 VPA). 0018 J1 : 1 - 3 16 J2 : 1 2 400522 - and 3 4 207COOFF 3 17 movea.l - tbase,a0 e point 'a0' at base address of SYN -ADC2 card F801 J5 : 1 - 2 400528 11700000 4 18 move.b t0,ddc(a0) e seLect channel zero, interrupt disabled J6 : 2 - 4 000C An analogue input should be 40052E 11400008 5 19 move.b d0,adc(a0) e start conversion (store anything) provided on P2, 400532 117C0080 6 20 move.b ih'80',ddc(a0) e enable adc2 interrupt output pin 15 (positive) and P2, any even pin (negative) 0000 for channel 0. 400538 027CF8FF 7 21 aedi ih'f8ff',sr e set processor int. mask to level 0 22e The G64 -VPA range on the Kaycomp is 40053C 60FE 8 23 hangup bra hangup o and wait FFF801 to FFFFFF; that is, the top 2K -bytes of 24 a the memory map. This is so that 40053E 7000 9 25 excep aoveq t0,d0 e clear 'd0' accesses to 400540 01080008 10 26 movep.w adc(a0),d0 e get conversion in 'd0' these absolute addresses may be made with a 400544 E848 11 27 lsr /4,60 e right justify it word -length address operand. 28 e 400546 22300000 12 29 moved 810000,d1 One of the above jumpers connects the inter- 2710 rupt output to the IRQ line of the G64 bus, which 40054C COC1 13 30 aulu d1,d0 a multiply by 10000 is in turn connected to IPLO, giving 1 40054E 223C0000 14 31 moved 14095,d1 a level OFFF interrupt. The a -to -d card generates an interrupt 400554 80C1 15 J2 divu d1,d0 e and divide by 4095 for answer in mV when a conversion is complete. 400556 02800000 16 33 andi.l ih'lffl',dO e truncate remainder Channel zero is ' FFFF selected on the a -to -d card in 34 e the program after the jmp.l instruction has been 40055C 4E48 17 35 trap 4/11 set up in the autovector 1 ram space, as with 40055E 0017 36 data 0,h'17' e call 'binbcd' the 400560 2001 18 37 moved d1,d0 e bcd result in 'd0' previous example. 400562 4E48 19 38 trap 811 The conversion is then started by writing (it 400564 00018 39 data 0,h'b' e print as 8 hex digits (out8hx) does not 400566 4E48 20 40 trap 1111 matter what) to the a -to -d register. 400568 0000 41 data 0,0 e and back into monitor The ADC2's interrupt output is then enabled 42 e and the processor's interrupt mask 43 e set to its 400564 44 end lowest level, 0, to allow interrupts at level 1. It then hangs up and waits for the interrupt to 26 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com occur, which will be about 351.4S later after the tions (odd or even), two or four depending upon a -d has finished converting. the size attribute, word or long -word. Processing than jumps via address 400016 to The read word is shifted right four bits to `excep'. Here, after clearing do, the 12 -bit right -justify it as, through a peculiarity of this conversion value is obtained from the card and card, the data comes out left -justified. placed in do. The 12 bits are obtained by reading The value read will be between 0 and FFF two consecute addresses of the ADC2 card, the (4095) for an input range of 0 to + 10 volts. So eight most significant bits from the first and the next it is scaled to represent millivolts by multi- four least significant from the second. plying by 10000 and dividing by 4095. However, because there is no ao line on the The divu instruction exits with the result in do, 68000, the processor al output goes to ao on the bits 0 -15 being the integer result and bits 16 -31 G64 bus and so consecutive addresses appear at the remainder. We are not interested here in the alternative addresses to the processor. So we remainder, so bits 16 -31 are forced to zero. Next need, in this case, to read FFF809 and FFF80B. this binary value is converted to b.c.d. and then Here the move p (move peripheral) instruction displayed as eight decimal digits, being the rsult comes to the rescue. It addresses alternate loca- of the conversion in millivolts

is only transferred via data -bit zero. If need be, the one ram SmartWatch real -time clock with ram byte affected can be stored elsewhere temporarily while the Building components into a socket gives a real -time clock and clock is read. battery- backed ram that plugs into many modern microcom- Any read from the ram area puters without hardware modifications. sets the 64bit code pointer in the clock circuit to its first location, when the With most computers, adding a products include electronic keys will only need to be read once which means that a read real -time clock involves at least and tags, an add -on serial port, when the computer is switched clock is to be accessed, precedes the plugging in a separate p.c.b. Ad- silicon delay lines and an on. From then on, timekeeping operation normally bits to be ding non-volatile ram can mean `intelligent battery'. These are can often be taken over by the string of initialization yet another p.c.b.. all available through Joseph computer. written. It also means that se- A computer real -time clock Electronics in the UK. Any ram byte can be chosen should the initialization decoding, a for accessing the clock because quence ever be interrupted by a needs address will crystal, power -down switching the clock- access sequence read operation, the pointer Accessing SmartWatch the first code bit. and a battery. Unless expensive through data -line zero depends be set back to electricially-erasable proms are Plugged into a computer 8K- only on states of the ram read, Minimum and maximum - controll- used, non -volatile ram also re- by-8bit ram socket, the device write, output enable and chip signal levels on all lines quires power -down switching appears in the memory map as a enable lines, i.e. those lines in- ing the clock are 2.2V logic high Normally add -on normal 8K- by -8bit memory. On- dicated on the diagram. Address and 0.8V logic low. Lines not and a battery. straight clock and non -volatile ram ly when a unique 64bit data line transitions during this controlling the clock go facilities constitute two separ- stream is sent to the socket does period are irrelevant as far as through the socket to the c -mos ate p.c.bs. the clock respond. After this in- the clock is concerned but data ram. With Smart Watch however itiation stream, the next 64 bits - the subject of our special offer written to or read from the on page 65 - the clock and all its memory area go to or from the associated circuits are built into clock. an 8mm -high socket. What is This method of accessing the more, the clock's lithium bat- clock means that only one byte tery and power- switching cir- of processor address space is cuits also connect to the top of needed, and only when the clock the socket so the 8K- by -8bit ram is addressed. With many fitted becomes non -volatile and operating systems, the clock remains so for 10 years. In some ram sockets, Timekeeping information in- com- cludes hundredths of seconds, Reset mainly in 6502 -based RST puters, the output -enable seconds, minutes, hour, day, signal is active during date, month and year. At the Daft input /output writing, which end of the month, the date is enable memory automatically adjusted for mon- means that SmartWatch Ground _ o without ths with fewer than 31 days, in- cannot be used cluding correction for leap GNO hardware modification. the clock Next month we'll show years. Whether such a modification and a in 12 -hour mode with Vic operates 6L pro- a.m. /p.m. indication or 24 -hour SmartWatch control v'c Write BBC micro- mode is selected by software. enable gram for the Output computer. Manufacturer of Smart- enable Watch, Dallas Semiconductor All pins on the Smart- produces various 'sockets', pins some with a ram and battery but Pin 20 Conditioned chip enable Watch socket except no clock and some with a clock On lower pins only 26 Switched Vcc for 24pin ram 20, 26 and 28 pass straight c static but no ram back -up facility so through to the -mos that eproms can be fitted. Other ram. 27 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com by P.B. Unstead and A. Blunden Eprom programmer for Apple II The second in a series of laboratory add -ons for the Apple and other 6502 computers

Below: memory dump of The real -time clock inter- the code generated by the face card which was BLOWER MODULE main listing (right). described in last 00000000 GLOBAL 0000coc0 pia SC000 CCOD 78 A9 00 8D Cl CO 8D C3 month's article included a 2K 0000ca0o table SC800 CC08 CO 8D 02 CO A9 FF 8D CO 0000CF9D key to SCF9D for these subroutines eprom programmed with firm- 0000FCA8 CC1O CO A9 03 8D FE 03 A9 EU Sit SFCAB see April issue ware to run the clock. 0000FD8E out SFDBE CC18 8D FF 03 A9 3F 8D C3 CO The 0000FDDA prbyte SFDDA CC20 AD C2 CO A9 34 8D C1 CO remaining 11K -bytes are free to 0000FDF0 coutl SFDFO 0000F94A prb12 SF94A cc28 AD CO CO 58 A2 45 AO 15 hold code to provide a variety of 00000023 wndbtm $23 CC30 84 23 20 4B CD 20 9D CF 000000E3 vai SE3 other useful functions, such as 000000F9 mode SF9 CC38 29 03 DO 01 60 4A 4A 6A 000000F9 8F9 CC4o 85 F9 A2 30 AO 28 20 48 the one described here. 00000750 acro $750 000000A0 CC48 CD A2 21 AO 99 20 4B CD blank SAO The 6821 p.i.a. consists of two 00000000 at BC0 S symbol CC50 A9 AO 8D DE 07 8D DF 07 000000C1 A BC1 CC 58 A9 Cl 8D El 07 A2 06 AO' parallel ports A and B each with 00000006 F SC6 000000DD brkt SDD square bracket I CC60 15 20 08 CD AO 24 20 08 two control lines cA(B)1 cA(B)2 0000CC00 ORG SCCOO CC68 CD AO 95 20 08 CD AS F9 0000CC00 78 en tr y0 SEI initialize and is located at the absolute 0000CC01 A900 LDA CO CC70 10 20 20 2E CD 78 20 E6 0000CC03 BDC1C0 STA pi a+1 data direction reg. A address COCO using 7421 gates 0000CC06 8DC3C0 CC78 CC A2 03 20 30 CD AD C2 STA pia +3 data direction reg. B 0000CC09 8DC2C0 STA CCBO CO A2 04 20 30 CD A9 FF and 7425 gates pi a+2 port B = input to decode the 0000CCOC A9FF LDA aSFF CC88 8D C2 CO A2 04 20 30 CD 0000CCOE BDCOCO STA pia port A = output address bus. The R/w 0000CC11 CC90 A5 F9 05 FF 8D CO CO A2 A903 LDA *3 set IRQV 0000CC13 BDFEO3 CC98 08 20 43 CD 20 43 (read/write) and E (enable) pins STA 603FE to operating CD A5 0000CC16 A9E0 LDA SSE0 system entry 0000CC18 CCAO FE 8D CO CU AO OU AS F9 are driven BDFF03 STA S03FF at SE003 directly from the 0000CC1B CCAB 10 14 81 FA 85 E3 8D C2 A93F LDA 553F CBI enabled edge connector of the Apple. 0000CC1D 8DC3C0 STA pie +3 CB2 manual high CCBO CO 20 2E CD A9 88 20 A8 0000CC20 ADC2C0 LDA pie +2 interrupt cleared CCB8 FC 20 2E CD FO OB 20 ZE The reset line, pin 34, is tied 0000CC23 A934 LDA 5534 CA2 manual low 0000CC25 BDC1C0 STA pia +1 A. B data ports CCCO CD AD C2 CO 85 E3 20 2E permanently high so that the 0000CC28 ADCOCO LDA pie interrupt cleared cCCB CD 20 5C CD 20 7E CD FO 0000CC2B 58 CLI chip 0000CC2C A245 CCDO OB can only be initialized LDX *S45 20 8B CD E6 FE DO C7 0000CC2E A015 LDY 5515 CCD8 E6 FF DO B4 A5 F9 10 03 under program control. 0000CC30 8423 STY wndbtm lift text window 0000CC32 204BCD CCEO 20 Eti CC JSR prhdg print options 4C 00 CC AO 08 The eleven lines required to 0000CC35 209DCF CCE8 JSR keyin keyboard select AZ 08 20 4B CD Ab FC O5 address the eprom are provided 0000CC38 2903 AND CCFO FD DO 08 A9 C6 8D 56 U7 0000CC3A D001 BNE entrylntryl 0000CC3C 60 CCF8 8D 57 07 20 3A CD A2 4C by the eight lines of port A pro- RTS return if "exit" 0000CC3D 4A entryl LSR A CD00 20 48 CD 4C 9D CF EA EA' grammed for output. For pro- 0000CC3E 4A LOR A 0000CC3F 6A ROR A mode =380 for burn CD08 20 08 CD 20 9D CF 20 25 0000CC40 gramming purposes the eprom 85F9 STA mode mode =0 for read CD10 CD OA OA OA OA 95 F9 C8 0000CC42 A230 LDX *$30 CD18 20 9D CF 20 25 CD 15 F9 is split into eight blocks each of 0000CC44 A028 LDY *$28 0000CC46 204BCD CD20 95 F9 C8 CA 60 C9 CO 90 JOR prhdg print heading for 256 bytes. 0000CC49 A221 LDX *$21 input of data CD28 0000CC4B 02 69 08 29 OF 60 A2 08 A099 LDY *599 in four -digit hex CD30 48 8A These are accessed by latch- 0000CC4D 204BCD JSR prhdg 4D C3 CO 8D C3 CO 0000CC50 A9A0 LDA *blank "eprom" changed to CD38 68 60 AD C3 CO 10 FB AD ing the three highest address 0000CC52 8D0E07 STA scrn+SBE r secondnd line CD40 C2 CO 60 BA 4D Cl CO 8D 0000CC55 8DDF07 STA ecru +SBF lines, A8 to A10 through a 7475 0000CC58 CD48 Cl CO 60 98 48 BD FF C7 A9C1 . LDA *A Aecii "A" 0000CC5A 8DE107 STA crn +S91 latch (Fig. 1). The block is 0000CC5D CD50 38 6A 99 4F 07 CA 88 90 A206 LDX *6 input eprom Start -addr 0000CC5F A015 CD58 F4 68 A8 60 AS FC 29 07 obtained through the p.i.a. LDY *$15 to data +5, date +6 0000CC61 2008CD JSR input4 CD60 DO 03 20 8E FD A5 E3 D1 0000CC64 PAO PA2, A024 LDY *524 input number of bytes outputs, to which are 0000CC66 CD68 FA 08 91 FA 20 DA FD A9 2008CD JSR input4 to data +3, data +4 0000CC69 latched by control line cA2 A095 LDY *$95 input ram address CD70 AO 28 FO 02 A9 DD 20 FO used 0000CC6B 2008CD JSR input4 to date +l, data +2 CD78 FD A2 02 4C 4A F9 AS FC as an output. 0000CC6E A5F9 LDA mode 0000CC70 CD80 DO 02 C6 FD C6 FC DO 02 1020 BPL addr skip if read mode The latch -enables, which are 0000CC72 202ECD JSR cb2 bring CB2 low CD88 AS FD 60 E6 FA DO 02 E6 0000CC75 78 SEI remove protection CD90 FB 60 active high, are obtained by 0000CC76 20E6CC JSR hivolt call programming voltage 0000CC79 A203 LDX *3 disable CBI, but taking cA2 low-high -low under 0000CC7B 2030CD JSR crbx make active low 0000CC7E ADC2C0 LDA pia +2 clear interrupt program control. 0000CC81 A204 LDX *4 DDRB 0000CCB3 2030CD JSR crbx Having latched the block 0000CC86 A9FF LDA 55FF 0000CC88 8DC2C0 address, the eight data lines of STA pia+2 port B is now output 0000CC8B A204 LDX *4 port B 0000CCBD 2030CD JOR data port port A provide the low byte of 0000CC90 A5F9 nexthi LDA mode mode in bit 7 0000CC92 05FF addr ORA data +6 high byte of eprom the address to the eprom, Ao to 0000CC94 BDCOCO STA Pia addreee bit 0 0000CC97 A7, whilst CA2 is held low to A208 LDX *8 of port A 0000CC99 2043CD JSR crax strobe latch disable the latch. The fourth bit 0000CC9C 2043CD JSR crax with CA2 0000CC9F A5FE neatly LDA data +5 of the latch allows PA7 to be 0000CCA1 8oC000 STA pia low byte of eprom addr 0000CCA4 A000 LDY *0 out of port A used, in conjunction with a 7432 0000CCA6 A5F9 LOA mode gate, to control the PGM /READ continued over page pin of the eprom; again, cA2 is 28 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com '/w 7432 25V supply socket I

IX 10V 5J 1 4k7 4k7 =100n

24 SVA A9 V OE A PG /CS D7 -D3 8 BB 10 To eprom socket Pin 26

A7 AO DQ D2 GND To

Pin 25 I 1 1 1 1 1 1 1 1 1 I I 12

Data fines 7432

5V `1 120 IIIIIIII 1111 16 J4 SV Pal I Pla0 P{ 4 P1 GND 1t1 C.I32CB1 2 10k 1 áI 1 6821 p,io. 3 14 R51 IRQgIRQAI 4 747S 13 RlWCSTCS1 g Q To Pin 25 5 12 Gÿ 21 1(111111 I 1 R /W +5V T0 Prf 26 18 6 30 11

GND To 71, 10 26 40 30 pin 26 Gnd 40,9 38 O D7 Dato bus 43 ,

Gnd To Pin 26 ENABIf 45 'i 7432

® 7625 49 k/I I 1 9 A7 Fig. 1. This eprom A 6 programmer programs 8 single -rail 2K devices A4 IRO These numbers refer to suitable for holding user 811 15 16 17 3 c6010 O13 Apple II interface connections firmware in the Apple II.

0000CCA8 1014 BPL read skip if reed mode 0000CCAA B1FA LDA (data +l),Y data from ram 0000CCAC 85E3 STA val (temp. for v.d.u.) 0000CCAE 8DC2C0 STA pie +2 output on port B 000QCCB1 202ECD JSR cb2 CB2 high 0000CCB4 A988 LOA #380 Below: subroutines. For details, see April issue. 0000CCB6 20A8FC JSR wait waft for 50ms 0000CCB9 202ECD JSR cb2 CB2 low 0000CCBC FOOB BED display skip 0000CCBE 202ECD read JSR cb2 CB2 low 0000CCC1 ADC2C0 LDA pia +2 reed data to C800 41 64 6A AC 40 9E 9C 40 Adj,@..@ 0000CCC4 85E3 STA val temporary location '(.$(@.. 0000CCC6 202ECD JSR cb2 CB2 high C808 A7 A8 82 A4 A8 40 82 88 0000CCC9 205CCD display JSR prval print data 40 8A AO 0000CCCC 207ECD JSR decnob count number of bytes C810 88 DC 40 92 9C .\@@ 0000CCCF FOOB BED deteend end if all done 74 48 60 60 60 $..tHttt 0000CCD1 2OBBCD JSR lncram next ram location C818 A4 9E 9A 0000CCD4 E6FE INC date +5 next eprom location 40 9C 9E 5E 84 B2 A8 `@..'.2( 0000CCD6 DOC7 BNE nextlo if high byte same C820 60 high byte muet 0000CCD8 E6FF INC date +6 if 8A A6 74 48 60 60 60 60 .&tHt ` 0000CCDA D0B4 BNE nexthi be incremented C828 0000CCDC A5F9 deteend LDA mode if burn mode C830 61 5C 8A BO 92 A8 40 62 a\.0.(@b 0000CCDE 1003 BPL end then ask for 5C 2@d\ 0000CCE0 20E6CC JSR hivolt programming volts oil C8C8 5C 86 9E AO B2 40 64 \.. 0000CCE3 4COOCC end J11P entry0 repeat 8A .*$.-;$ ar kaa.asaaw } + *xaaaaa ****r +v..a C840 84 AA A4 9C 7E BB A4 subroutines 9C (*$. 0000CCE6 A008 hivolt LDY sb C848 A8 AA A4 0000CCE8 A208 LDX s8 continued on page 30 29 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com EPROM PROGRAMMER

0000CCEA 204BCD JSR prhdg print "L5i ott * * ** * * * * * * * * * * * * ** * * ** * * * * * * * *** 0000CCED ASFC data +3 LDA 0000CD43 8A crew TXA 0000CCEF 05FD ORA data +4 if no data lett. 0000CD44 4DC1C0 FOR piaci change 0000CCF1 D008 BNE on then skip selected 0000CCF3 A9C6 LDA 6F Ascit"F" 0000CD47 8DC1C0 STA +1 0000CCF5 8D5607 +6 pia bits of CRA STA n 0000CD4A 60 RTS 0000CCF8 8D5707 STA n +7 change "ON" to "OFF"' * * * * * * * * * * * * * * * * *** * ** * * * * ** * *** 0000CCFB 203ACD on JSR poll 0000CD4B 98 prhdg TYA 0000CCFE A24C LDX $$4C wait until IRQB is set 0000CD4C 48 0000CDOO 204BCD PHA save Y register JSR prhdg print "RETURN" and wait 0000CD4D BDFFC7 next LDA 0000CD03 4C9DCF JMP keyin table -1,X read character 0000CD50 38 SEC 0000CD06 EA NOP 0000CD51 6A ROR 0000CD07 EA NOP A (not inverse field) 0000CD52 994F07 STA * * ** * * * * * * * * * * ** * * * ** * * * * * * * * * ** corn -1,Y print it 0000CD55 CA DEX 0000CD08 200BCD input4 JSR input2 next character input two hex digits 0000CD56 88 DEY 0000CDOB 209DCF input2 JSR keyin next screen location character from keyboard 0000CD57 90F4 BCC 0000CDOE 2025CD next odd value marks end JSR digit one digit 0000CD59 68 PLA 0000CD11 OA ASL A of message 0000CD5A A8 TAY 0000CD12 OA ASL A 0000CD5B 60 RTS 0000CD13 OA ASL A shift digit * * ** * * * * * * * * ** * * * ** * * * ** * * * * * * ** 0000CD14 OA ASL A to top four bits 0000CD5C ASFC prval LDA date +3 output 0000CD15 95F9 STA data,X and save 0000CD5E 2907 0000CD17 CB AND *7 every eight bytes . INV next screen location 0000CD60 D003 BNE 0000CD18 209DCF keyin ekip JSR keyboard 0000CD62 208EFD JSR 0000CD1B 2025CD digit cuo t JSR 0000CD65 A5E3 skip LDA 0000CD1E 15F9 val ORA data,X join two digits and 0000CD67 D1FA CMP 0000CD20 95F9 (date +l),0 STA data,X save as byte 0000CD69 08 PHP 0000CD22 C8 INY next screen location 0000CD6A 91FA STA 0000CD23 CA (deta+l),Y store data in m DEX next byte 0000CD6C 20DAFD JSR 0000CD24 60 RTS prbyte print data on v.d.u. 0000CD6F A9A0 LDA * **** * * * * ** * * * * ** * *** * * * *** * * * ** *blank 0000CD71 28 PLP 0000CD25 COCO digit sat mark if CMP Ascii O 00000072 F002 BEQ 0000CD27 9002 same old value differs BCC numo if numeric, skip 00000074 A9DD LDA 0000CD29 6908 sbrkt Ascit ADC *8 0000CD76 20F0FD same JSR 0000CD2B 290F coutl sumo AND $8F select four low bits 00000079 A202 LDX 0000CD2D 60 *2 print two blanks RTS 0000CD7B 4C4AF9 Joy * * * * * * * * * * * * * * ** * * * * * * ** * * * * * * ** prb12 0000CD2E A208 cb2 LDX *8 manual level 0000CD7E ASFC decnob LDA +3 0000CD30 48 crbx FHA date save accumulator 0000CDB0 D002 BNE lobyte 0000CD31 8A TXA decrement number of 0000CD82 C6FD DEC data +4 0000CD32 4DC3C0 FOR pia +3 change selected 0000CD84 C6FC data bytes lobyte DEC data +3 zero 0000CD35 80C3C0 STA pia+3 bits of CRB 0000CD86 D002 flag Is set BNE return' clear on 00000038 68 PLA 0000CD88 ASFD return 0000CD39 LDA date +4 60 RTS 0000CDBA 60 return' RTS * ** * * * ** * * * * * * * * * * * * * * * ** * * * * * ** * ** * * ** * * * * * ** ** * * * * * * * * * * * * * * ** 0000CD3A ADC3C0 poll LDA pia +3 0000CDBB E6FA incram 0000CD3D INC data +l Incrementment vec 10FB BPL poll weit until bit 7 is set 0000CD8D D002 BNE 0000CD3F return2 tot am ADC2C0 LDA pia +2 clear interrupt 0000CD8F E6FB INC 0000CD42 data +2 60 RTS 0000CD91 60 return2 RTS Assembly Complete

The register selected to status of bit 3; if bit 3 is set the appear at the shared is 6 5 4 3 2 1 0 address line is high. controlled by the status of 2 li bit IROA(B!1 IRQA(B)2-CA18)2 control --. OAccce(ss cont o11_ of the appropriate control register. If bit 2 is cleared kead only Read, write the Finnware DDR is accessed; if set, the i/o register is selected. The 6502 code is entered by Call (52224). The user then selects 1 (above): used as a latch enable. The control register format is Table control Exit, Read or Burn. Exit may be For the read mode PA7 is low given in Table L Bits 7 and 6 are register fromat of the followed by Call (52526): Poke 6821. and CB2, programmed as output, interrupt flag bits for the cA(B)1, 249,0 : Call (52290) in is transmitted to pins 18 and 20 CA(B)2 control lines; the flag is order to read a rom. The of the eprom. Data is set to logic 1 when the pro- user next enters Below: this Basic program then read the eprom start address, modifies through port B while cB2 is grammed transition occurs on the code number of bytes and generated by pulsed low- high-low. the appropriate control line. If ram start the main address in hex notation. listing so In programming mode, PA7 the interrupt is disabled the that the In Read mode, the software can program its is latched high and the or gate related IRQ line from the p.i.a. program then copies the specified area of own holds pin 20 high; cB2 is pulsed will not be taken low and the eprom. the eprom to ram and high -low-high for 50ms while processor will not be inter- indicates whether the byte previously 10 the data is held on port B output. rupted. The flag bit will FORI =26624 TO 28671 held in ram was same, 20 X= PEEK(I) Line CBI senses however be set; it is cleared by the for the 25V pro- verification. 30 IF X =205 THEN X =93 gramming supply and reading from or writing to the In programming so pro- mode, the 40 POKE (I- 4096),X vides circuit protection through port. program asks the 50 NEXT In user to insert the 25V connec- 60 POKE 23763,91 software. the same way, the cA(B)2 control lines are programmed tion and burns the code into the 70 POKE 23887,87 eprom, displaying 80 POKE 23672,92 by switching bit 5; if bit 5 = 0, the data as it does so. 90 POKE 23778,92 the line is an input. The cA(B)1 Software 100 POKE 23781,92 lines operate only as inputs. 110 POKE 23607,95 Externally the p.i.a. appears as For input control lines, a 120 POKE 23813,95 Self- programming 130 POKE 23821,95 four consecutive register loca- further bit specifies which 140 POKE 23834,95 tions, but internally there are six transition will set the IRQ flag With a few modifications, the 150 CALL (23552) registers: three for each of the bit. If the transition is to be 1 to code can be used to generate its two ports. The data direction 0, a zero must be written to the own firmware. Enter the code registerLDDRA(B) and the appropriate bit. The logic state into ram at $6800- $6FFF, then input /output register ORA(B) written to the bit indicates the copy it, using the Basic program share a register location; the status of the line after the (table 4), into ram at unique locations are occupied by transition has occurred. $5800-$5FFF. the respective control registers. For cA(B)1, bit 1 is used to The program alters the high The shared addresses are Base control the transition whilst bit 4 bytes of absolute addresses (A port) and Base +2, (B port). indicates the required transition $C7, $CB, $CC, $CD and $CF to The port is programmed by on those cA(B)2 lines configured new values ($57, $5B, $5C, $5D writing to the corresponding bit as inputs. When the lines cA(B)2 and $5F). The eprom proof the DDR; 0 configures a line are configured for output, if bit 4 grammer may then be operated for input and 1 configures it for is set to 1 the status of the by calling the modified code output. control line is determined by the with CALL (23552). 30 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com COMMUNICATIONS COMMENTARY

a primarily in terms of national cent more than in 1984. The This time the plans include JAM TODAY prestige and propaganda. main reason is the enormous satellite link from the base camp to the UK, plus the use Unless a solution to the The jamming problem, deficit of about $17,500 -million of Racal 10 -watt manpack sets of deliberate unfortunately, could easily with Japan, much of it due to problems h.f. transmitter can be found at spread to the microwave bands importing $11,700-million and a 100 -watt interference links with North second session of the for satellites, with their worth of consumer products to maintain the and Portishead Radio. World Administrative Radio increasing use for such from that country. Only in America The manpack sets have been Conference for the planning of purposes as the world -wide computers did the USA down to temperatures as the h.f. broadcasting bands, television exchanges already in achieve a worldwide positive tested held at Geneva from operation by the United States balance. Japan's NEC has low as minus 45 degrees due to be The team are 27 to March 13, 1987, Information Agency, and the taken over from Texas Centigrade. January special lightweight (500 little progress is likely to be future possibility of high -power Instruments as the world's using lb) sledges made by British achieved and the conference direct -broadcast satellites largest supplier of integrated Aerospace and designed to may collapse. This pessimistic targetted at East Bloc circuits. One result has been should they fall was expressed by Bert countries. There is a popular the hardening of the yen /dollar stay afloat view ice with a full 600 engineer of BBC view that d.b.s. is impossible to exchange rate by about 25 per through the Gallon, chief seeking in a recent jam. In fact this could be done cent in recent months, with lb load. They are External Services, on "Waveguide" broadcast. all too easily by squirting Japanese firms trying to hold scientific information pollution and the At peak listeining times as signals at the receiver of the their market shares in capital atmospheric of the ice shelf. much as 60 to 70 per cent of satellite transponder. equipment by not raising prices structure available spectrum is being Although jamming is to an equivalent degree, but badly affected by jamming. contrary to the radio already losing some of their This affects listeners in regulations, it could be argued consumer -market to Korean SPACE OUTLOOK countries far beyond those to that a United Nations industry. UK may or may not have which the jamming is directed. recommendations on space The d.b.s. system in The Russians are currently broadcasting states that this a high -power should not be targetted ARCTIC LINKS operation by 1989 or 1990. We jamming, in an extremely see what the towards another country Providing communications in shall have to wait and sophisticated manner, IBA programmes without the agreement of the the Arctic presents severe response there is to the Russian -language Meanwhile the Voice of America, country concerned. It would, problems both in terms of the advertisements. of the BBC, timetable for other Welle, Radio Free for instance, be one thing for very difficult h.f. propagation provisional Deutsche high -power and Radio Liberty, Radio the Federal Republic of conditions (polar cap European Europe, -power satellites is Israel and Radio Peking. The Germany to put out their own absorption and extreme intermediate French TDF -1 and other country jamming national programmes on a multipath) and in the provision that the only West German TV-SAT could BBC transmissions is Poland. satellite whose footprint of light -weight, easily -powered launched later this year, China jams programmes from extended over the whole of radios that will continue be providing up to four the USSR. With the narrow East Germany and beyond, but working at the sort of extreme both channels from orbital position 5kHz channel spacing and the quite a different matter if the low temperatures that can 19° East with transponders mixture of very high and satellite carried programmes cause co -axial cable, unless putting out more than 200 medium power transmitters on expressly for that area. A especially treated, to watts of r.f. If all goes well h.f., the jamming spreads over majority of viewers in East disintegrate at a touch. -1 should be receivable more than the target channel Germany can, in fact, already The three -year "transglobe" TDF much of the UK with can pause problems as far receive West German expedition of 1979 -82 under over and small dishes, and may have an away as South America and television from terrestrial the leadership of Sir Ranulph transmitters, and viewers who Fiennes experienced their most English -language service Australia. Robert Maxwell, The USSR has an elaborate take advantage of this are no difficult radio problems while provided by in the but it is by no means certain costly network of ground - longer harassed by the in the Antarctic and later and there will not be further wave jammers for urban areas authorities as they once were. Arctic. I recall talking to Lady that delays. The Yuri of more than 100,000 But then East German tv can Virginia Fiennes, the base Japanese Racalex 82. BS -2b (not receivable in and powerful sky - be viewed as far west as station operator, at population was launched in to blanket Hamburg and I am told is She explained that on Europe) wave jammers with three 100 -watt suburban and rural area. Over popular because of the occasions propagation was so February but it will be they have learned a spectacular State -subsidized bad that s.s.b. from the transponders, the years, time before anyone can great deal about the technique films with, as the cinema used forward man -pack set had to some be sure that these will not of jamming, seldom wasting to proclaim, "a cast of give way to slow morse. The suffer a similar fate to two of power on what they regard as thousands ". biggest worry was that of but providing electric power for those on BS -2a. The "harmless" programming power" very quickly the portable units at times "intermediate switching on SES satellite when an "objectionable" USA IN THE RED when the petrol -electric Luxembourg being built by RCA is expected programme begins, following For many years one has generators carried on the not to be launched in 1987 with a any sudden changes of thought of the USA as the motorised sledges were capacity of 16 television frequency promptly and heart -land of radio available. communications and During early March, Sir channels. With 45 watts per effectively. e.i.r.p. of interference electronics, the large domestic Ranulph Fiennes, with channel and an Non -deliberate it should be receivable mostly from poor market giving the economies of scientist Oliver Sheppard and 50dBW arises over most of west Europe on spectrum management and scale that made their products radio engineer Lawrence on the dishes of about 0.9 to lack of experience in some sellable in every country that Howell, left Heathrow into 1.2 -metre diameter. It has an countries. The h.f. broadcast could find the dollars to pay for first stage of a new probe from a Ariane launch booked. The spectrum is the least well them. Yet in 1985, the USA the Arctic to be made had a world -wide electronics base camp on Ward Hunt American hold on regulated of any of the launches allocations, and is deficit of an estimated island some 400 miles from the geostationary broadcasting following the Shuttle disaster seen by many governments $8600- million, almost 40 per North Pole. 31 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com COMMUNICATIONS COMMENTARY

seems bound to increase the radio equipment should seek to pressure to get on to Ariane. TVI TURN -ROUND ensure that their products do THERMIONICS Papers presented at a recent What appears to be a major not cause interference to radio The 50th anniversary of the IEE colloguium on change in the official DTI users. Orders exist for some introduction by RCA Radiotron "Operational experience in the approach to difficult cases of types of equipment and where of the 6L6 valve in 1936 has use of the European radio -frequency interference, appropriate others will be sparked off a good deal of communications satellites for following the phasing -out last made. nostalgia among radio television tansmission" was year of free investigation by "Where it proves impossible amateurs who still recall with concerned exclusively with the the Radio Investigation to resolve individual problems something approaching use of the Eutelsat F1 (13° E) Service, was disclosed in a and the affected apparatus has genuine affection the series of and F2 (7° E). F1 carries a Parliamentary reply by Mr been brought up to a beam tetrodes that included number of the services for John Butcher, Secretary of reasonable level of immunity, I the 6L6, 807 and 813 that filled European cable systems. F2 State for Trade and Industry. intend to vary the terms under so many transmitter sockets includes EBU news and The reply, combined with the which the relevant amateurs over many years. I wonder if programme exchanges and belief that new licence are licensed; where necessary solid state devices will come to occasional use for satellite regulations for amateurs are in (and I hope it will not be be remembered in this way? news gathering (SNG). the offing, is causing many necessary often) licences will How long before we are Most speakers agreed that rumours to circulate about be revoked. talking nostalgically of the 555 the Eutelsat systems have been future power restrictions. "In this particular case (at or even the OC171? very successful but equally it is Mr Butcher stated: Eastcote, near Pinner) I will For many amateurs, the clear there have been a number "Problems can arise when high vary the powers which the valve is still the easiest and of problems. The drop in power radio transmissions are amateur is licensed to use and surest way to obtain lots of r.f. performance of the made in close proximity to restrict his use of certain watts. The 813 is still in transponders used for Sky radio and television sets, or bands. If this does not resolve demand for s.s.b. linear Channel and the Belgian film indeed a range of electrical the problem, I shall further amplifiers, along with the channel has so far not seriously apparatus not designed to review the position." modern high -perveance valves affected the services, but has receive radio. Such problems While few amateurs would that can be decidely more shown an unexpectedly high can be exacerbated by disagree with the DTI's temperamental unless carefully rate of degradation of two of equipment which is deficient in analysis of the problem, many handled. the Telefunken travelling wave its ability to reject unwanted are extremely worried at the I note that the British tubes. signals or in the case of radios new threat of varying or Vintage Wireless Society is There is also a difficulty in and televisions which have an revoking a licence where the sponsoring a three -day, making meaningful cost inadequate or defective aerial transmitter is causing break- 15- lecture course on "Early comparisons between satellite or no aerial at all. The problem through and not harmonic Wireless - the thermionic age and terrestrial links due to is growing because more and interference. This reverses the past and present" at Imperial fluctuating exchange rates and more homes now contain a procedure that has existed for College, London SW7, July 7 the use of Swiss Gold Francs great range of electric many years. This has meant to 9. A snag for retired on terrestrial links and equipment; and high power that an amateur causing engineers and amateurs is that European currency units (ecus) transmitting equipment is now breakthrough interference will the fee, including lecture notes on the leased space segments. more widely available to the not be prevented from etc, is £85. Course organizer is A major problem for SNG is growing number of amateur operating within the terms of Dr L.L. Freris, Electrical the need for frequency co- radio licensees. his licence except temporarily Engineering Department, ordination before a 14 GHz "Radio amateurs generally while the RIS team advise the Imperial College, London SW7 uplink can be used from a take a responsible attitude to viewer on a cure. Furthermore, 2BT. temporary site. the problems their only appliances intended to Looking through the list of For equipment designers transmissions cause. Equally, receive radio or television have topics one wonders how many there is still the problem of the manufacturers are keen to been the concern of the D.T.I. of the present generation of different transmission produce equipment which has It is understood that British amateurs are familiar with standards including deviation adequate immunity. Standard BS905, intended to such techniques as reflex, (bandwidth), pre- emphasis, Regrettably, a few amateurs improve the immunity of tv neutrodyne and audio, sub -carrier spacing, and manufacturers do not have receivers primarily against CB superinductance. But the use audio bandwidth plus the a responsible attitude; it is they 27 MHz interference is being of the valve in modern different colour encoding who cause problems. put aside in favour of the transmitters and hi -fi systems, etc. The outlook for a European specification. While equipment is also to be single European transmission "My officials are currently this will help minimise the covered. The possibility of a standard is still unsettled, discussing with BREMA and problem of breakthrough from considerable return to while a world transmission the RSGB the implications for low -power transmitters there thermionics as a protection standard grows ever less them of the new standard for may remain problems of against equipment damage likely. Latest contender to television immunity currently breakthrough interference in from nuclear electromagnetic enter the h.d.tv stakes is a under discussion internationaly close proximity to high -power pulses is still on the cards, with BBC concept called digitally and procedures for dealing transmitters unless the sets are the American Naval Research assisted television (d.a.tv) that with individual cases where fitted with additional filters as Laboratory claiming to be involves the transmission of interference is caused. I would in the past. It seems likely that working on microminiature analogue picture signals like to see sensible immunity the DTI will wish to introduce thermionic devices. together with high data -rate standards observed by all regulations restricting the PAT HAWKER, G3VA digital signals carrying control manufacturers and importers effective radiated power of or supplementary information of radio receiving and radio amateur transmitters, about the picture and claimed sensitive equipment. Where particularly on microwave to put an h.d.tv picture into possible and appropriate these bands, where high-gain home receivers, even when the will be enforced by order. antennas can result in very bandwidth of the signal has Similarly, manufacturers and high e.r.p. from relatively low - been reduced.I importers of radio and non- power transmitters. 32 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com CIRCUIT IDEAS

Quad switch as Vdc S1 I 52 A B

SR latch L H L H A set /reset bistable latch can H L H L be configured from two sections of a 4016 or 4066 c- L L L L mos quad bilateral switch. Two transmission gates are cross -coupled as shown. Closing S2 causes gate a to be A is non -conducting; point s1 / therefore high and so gate b conducts. Because gate b is 0 conducting, point B is low, holding gate a open when S2 is released. When Si is closed, gate b is open circuit, point B goes high The remaining two and gate a conducts, making transmission gates may be point A low and so holding arranged as a one -pole two- gate b non -conducting. The way switch, a two -pole one- truth table is shown. way switch or as two one -pole If a known power -up one -way switches, and may be condition is required, C1 may driven by SR latch outputs at be added across Si to make points A and B. sure that gate a is conducting J. E. Noakes and gate b is open circuit at Camberley ` o 1 pole ?way 2 pole 1 way 2 Opolepole 1 way switch on. Surrey

Automatic power swiitch and headphone amplifier

I have used this battery- Power consumption is 5mA power switch and the when switched on and about 'Vin Vout headphone amplifier for about 13014A when off; if the unit is Trp 11 a year now with my Sony switched off for long periods, 1 Walkman DD and Sennheiser add a normal power switch. R1 C1 ° R2 BS250 Audio 660k 15k 122)J <017 HD430 headphones. Philip Bosma inputs Di to 2M 2 (see text) needed as the 14 Amplification is Enschede -VVM Tri Walkman has a 3211 output and The Netherlands 47k AA119 the headphones are 60011. 22y 47k 2p2 BC 549 Audio is amplified by Tr1, vw rectified by Di and charges C1 47k to switch on the mosfet Tr2. 22p Resistor R2 determines delay 15k between loss of audio and switch off, which is usually greater than 1min. Value of R1 is determined by x' All capacitors except these ore tantalum. fitting a 2.2M0 potentiometer in its place and adjusting it so '18V that Vaat is zero with no audio, rising to V1e within a few 220k Headphones seconds when audio appears. 2 x 60011

-0F I \) S ereo in 2p2 5k6 aC]o cf d(b p 10k o 1a 9V 22y2 5k6 22.J cD)opc 10k ("7-'4 33 33 220k °N"g o{d, 22y 18V

ELECTRONICS & WIRELESS WORLD MAY 1986 33

www.americanradiohistory.com CIRCUIT IDEAS

Line driver Inexpensive 1 50V regulator In order to drive c -mos at a .12V Using a 100V complementary pair as a shunt regulator distance, an active pull -up is provides a solid -state alternative to neon stabilizers. Point X is required. held at 75V relative to either rail, providing 150V. At 100mA, Active current sinking is 4k7 amplification of the TIP41C /42C pair is greater than 100. provided by a high- voltage t.t.l. David Hoare 7406 inverter or 7407 buffer Leicester while the BC183L acts as a BC 183 current source when 300V the t.t.l. d c 150V regulated output goes high. 1k5 This circuit has been used to 20W drive a c -mos input at 2MHz 1N 914

over 3m of twisted pair. TIP 410 J. Shaw 7406 or 7407 Dunfermline 75VX Total load Fife reg 100mA TIP 42C

Note- ea h transistor on 6°C /W heats ink

Development interface This Z80 Spectrum interface reads most single -rail eproms or to transfer contents from C000 onwards to an emulator, and reads and writes non -volatile rams and battery- backed eprom emulators such as the GR2716. ORG B030 We use assembly language on the Spectrum for developing LD BC,0800 ;1000 for industrial control applications software. Code is assembled LD HL,C000 4K devices then transferred to an emulator using the interface. LOOP2 LD A,(HL) OUT (1F),A To transfer eprom content to ram starting at C00016, INC HL DEC BC ORG B000 LD A,B LD BC,0800 ;1000 for OR C LD HL,C000 4K devices JR NZ,LOOP2 LOOP1 IN A,(1F) RET. LD (HL),A INC HL Supply switching linked to the zero -insertion force socket DEC BC allows eproms to be inserted and removed while the computer LD A,B is powered. OR C Hamid Mustafa JR NZ,LOOP1 Sola ADC Lenses RET Ireland

+SV

S 4k7

+SV __LL0L L 1511611 6 CS B DO D7 2716, 6116, GR2716, 124 Operated by O 181 pl 2732, GR2732, 2532 1 zit socket D O I lever zif socket 211 12 E O I A WE .A10 F 0 8 6 5 4 3 23 22 19 A11 G o-

Gnd H

4k7 9 7 6h32 4 13 2 14 15 +5V

Links 16

2716 : A- E, B-C, D-H 10k 6116 : B-C, D-H, E-F 4040 B GR2716: B-C, D- H, F-WE All single rail 10 11 C IReset 2732 : B-C, D-H, E-G 5V devices GR2732: B - C, D-H, E- G, F-WE 10k 2532 : A-E, B-D, C-G

On a 4K device, if only upper 2K is to be used, for 2732 E -A instead of E-G For 2532 C -A instead of C- G.

34 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com VESTIGIAL SIDEBAND TAYLOR TELEVISION MODULATOR C.C.I.R /3

CRYSTAL CONTROLLED OSCILLATOR 19" RACK MOUNTING, lu HIGH, 205mm DEEP

C.C.I.R /3 SPECIFICATION

Power Requirement - 240V 8 Watt )available in other voltages) Video Input - 1V Pk -Pk 75 Ohm CHANNEL COMBINER /FILTER /LEVELLER Audio Input - .8V 600 Ohm to combine outputs of modulators F.M. Sound Sub -Carrier - 6MHz (available 5.5MHz) Modulation - Negative /Combiner /Leveller. Insertion Loss 3.5dB I.F. Vision - 38.9MHz TCFL2 2 Channel Filter /Leveller. Insertion Loss 3.5dB I.F. Sound - 32.9MHz )available 33.4MHz) TCFL4 4 Channel Filter /Combiner x TCFL4 to be combined. Sound Pre- Emphasis - 50us TSKO Enables up to 4 TCFL2 or Ripple on I.F. Saw Filter - .6dB Output (eny channel 47- 860MHz) - +6dBmV (2mV) 75 Ohm Vision to Sound Power Ratio - 5 to 1 Intermodulation - Equal or less than 60dB Spurious Harmonic Output -40dB 180dB if fitted with TCFL1 Filter or com- TAYLOR BROS (OLDHAM) LTD bined via TCFL4 Combiner /Leveller SISLEY STREET WORKS, LEE STREET,

C.C.I.R./3.1 Specification as above but output level 60dBmV OLDHAM, ENGLAND. 1000uv TELEPHONE: 061 652 3221 TELEX: 669911

CIRCLE 32 FOR FURTHER DETAILS.

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All the latest fastest devices not to be confused with slower old stock offered elsewhere. DRAM EPROM 5vNMOS 150nS 5vNMOS 250nS 4164 64k x 1 £1.20 2716 2k x 8 £3.25 41256 256k x 1 £2.80 2732 4k x 8 £3.25 4416 16k x 4 £2.95 2764 8k x 8 £1.95 NMI 41464 64k x 4 £5.90 27128 16k x 8 £2.85 SRAM 27256 32k x 8 £4.95 5v CMOS 27C64 8k x 8 £8.50 VMC-02 KIT ONLY £19.95 inc. VAT. + £2.50 p&p (Kit does not include video head) 6116 2k x 8 £1.65 27C256 32k x 8 £15.00 NOW FOR INFORMATION OF THE 6264 8k x 8 £3.50 TELEPHONE US REPLACEMENT HEAD FOR YOUR VIDEO RECORDER. ORDERS OVER £25 DEDUCT 10% DISCOUNT ADD 15% VAT SENT POST FREE. ORDERS UNDER CATALOGUE: For our full Catalogue of Replacement Motors, £25 ADD 15% VAT PLUS 50p P &P. OVERSEAS ADD £2 P &P No VAT Video and Audio Cassette /Reel to Reel Heads, Mechanisms, etc. Please forward 50p p&p. MICROKIT LIMITED THE MONOLITH ELECTRONICS CO. LTO. MANOR PARK .RAUNDS 5-7 Church Street, Crewkerne, Somerset TA18 7HR, England. - Telephone: Crewkerne (0460) 74321 Telex: 46306 MONLTH G NORTHANTS NN9 6PD _ Technical advice etc., please phone 0933 626420 24 hour service

CIRCLE 53 FOR FURTHER DETAILS. C IR( 1,1;;3f) I f)I( I`l lt"l'lll:ll I)F:'h\I1,5.

ELECTRONICS & WIRELESS WORLD MAY 1986 35

www.americanradiohistory.com by H. W. Gleaves An introduction to 3D graphics

Principles for producing three - dimensional images in perspective are discussed, with an implementation example in QL Basic.

Many personal computer users description takes the form of a Because our 3D a.e. takes this regard computer graphics - numerical model of objects in form, it means that all objects in especially 'three dimensional' the artificial world, or environ- the 3D a.e. must be constructed computer graphics - to be both ment. from plane, that is flat, complex and specialized. For polygons, but this is not a signi- these reasons many people Three -D artificial environment ficant restriction. avoid one of the most interes Thus the 3D a.e. contains the ting and effective applications Such a model constitutes what is description of real, material of a personal computer. termed a 'three dimensional objects and does not relate to To fully understand the artificial environment', or the viewer in any way. It is a 3D subject requires great effort and simply a.e. Given a 3D a.e. generalized description of the study; modern state -of- the -art and appropriate software, it is objects to be viewed. possible to computer graphics, is a highly produce perspective The 3D a.e. is a data -base, but images of developed subject, demanding the environment from is implemented in Superbasic as position the highest performance any and orientation. a number of arrays. Since the Hugh Gleaves initially trained as possible from computers. The environment used in this 3D a.e. only contains array an Electronics Engineer, became Forming an introduction to system has an hierarchical references, integer arrays can interested in computing, and took the subject, this article demon- structure as shown in Fig. 1. be used to save memory and a position as a computer strates how a microcomputer Every object in the 3D a.e. is increase system speed. programmer for London -On -Line graphics system for construc- referred to as a body. Each body Local Authorities, L.O.L.A., in is referenced by its body Enfield, Middlesex. There he ting object outlines is devel- number and a learnt how to produce structured oped. These outlines, or 'wire constructed from number of A The viewing process modular program using PL /1, and frames', are in perspective and polygons. cube for also the fundamentals of data- can be constructed in any example has six polygons. Now comes the problem of base programming. position and orientation. Furthermore each polygon has a constructing an image of the Hugh's main interest however Superbasic on the Sinclair QL number of vertices. region of the 3D a.e. in view. is in computer applications rather is used to show how the graphics Finally each vertex has three Imagine that you are inside a tv than data processing and he took system is implemented. Ele- coordinates uniquely identi- camera that floats freely in the the opportunity of studying for an mentary algebra and trigono- fying its position in space. 3D a.e. and can be pointed in any HNC in cad /cam at Merton College in Surrey, having been metry are used but you can skip with L.O.L.A. for 3 years. over these and just use the pro- Hugh's other interests include grams without studying their E}tIt AU ? computer graphics, internal workings if you wish. PITCH ? Y? electronics ROIL ? Z? and artificial intelligence. Applications for such graphics software up are to you; one ------_ obvious use is games, but time taken to compute the images has to be taken into account. It would be interesting to see how the software presented here performs when written in assembly language or speeded up by some other method such as compilation. Because we want to be able to view objects in the graphics system from any position and orientation, a description of the objects must be present. This 36 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com desired direction and in any coordinate system through the orientation. specified angles. New coordin- The imaginary camera itself ates of any point relative to the has coordinates, CX,CY,C,, as coordinate system can then be Body well as three orientation calculated as shown in Fig 2b. components, roll, pitch, and A similar set of equations yaw. Parameters roll, pitch and exists for three dimensions. Our yaw are three angles that imaginary camera can now be uniquely specify the imaginery placed anywhere in the 3D a.e. camera's direction, and are pointed in any direction, and measured with respect to the coordinates of any point in the camera's coordinate system. 3D a.e. with respect to the Polygon Polygon There are thus two coordinate camera can be calculated. systems. The first describes all Calculation takes place in two points in the 3D a.e. including steps as described above. camera position and the second Given the camera's position is an identical coordinate and orientation, six numbers in system that is fixed with the all, the position of any point in camera, i.e. each point in the the 3D a.e., relative to the Vertex Vertex environment has two sets of camera can be calculated. But coordinates, those relating to its this is only half the story. A two - I position in the 3D a.e. and those dimensional picture still has to relating to its position relative to be constructed from the 3D the camera. data. This final stage of the 3D To compute the image seen by a.e. manipulation involves the camera, the position of all finding screen coordinates of a z points in the environment point given its 3D coordinates in Y relative to the camera needs to space. This is simply another be known. These relative co- transformation process, Fig. 3. ordinates depend on the camera Several types of trans- position and orientation in the formation are available that Fig. 1. Hierarchical 3D a.e. and can be calculated allow a two dimensional image of the point in the 3D a.e. If this structure of the 3D a.e. from the real coordinates. to be produced. This article is process is carried out for every data base. The process of obtaining primarily concerned with a class point in the scene, and points on these coordinates is trans- of transformations known as the screen joined in the same formation - a mathematical perspective transformations. order that they are joined in the term to describe the process of In a perspective trans- scene, then a perspective image obtaining coordinates in one formation, a point in space will have been produced on the system given the coordinates in known as the focal point is screen. another system. designated and a surface is Transformation takes place in introduced, in our case a plane Perspective transformation two stages in the program (to surface, between the focal point follow). In the first stage, trans- and the scene to be viewed. There is a simple mathematical lation, the second coordinate Now, an image is `projected' relationship between the point's system is placed at the specified onto the plane or screen. true coordinates and the position with axes parallel to the Projection takes place as coordinates of its projection. original coordinate system. follows. For every point in the The equation relating this is New coordinates of any point 3D a.e., or portion of the derived with reference to Fig 3. can then be found very simply, environment being viewed, The diagram shows the as Fig. 2a shows. construct a straight line from simple geometrical relationship The second stage takes the that point to the focal point. The between the true and per- previously found coordinates of position on the screen that this a point and rotates the line penetrates is the projection The cover photograph is an example of an advanced 3D graphics processor. Software producing this picture the subject of a future article - is based on the principles and programs dealt with in this issue. Wire - frame objects, like those on the right, are produced using software to be shown in the next issue. Shown left is an object drawn in full perspective 3D. The system supports full colour, polygon outlining, back face removal, and hidden feature removal. An automatic surface area calculator is included that can calculate the total surface area of any 3D body in the system, which brings it into the realm of simple CAD. The photograph is taken directly from the monitor, and shows just one facility of the powerful menu orientated system. Other facilities are object Load /Save on microdrive, and an improved form of motion control. How the system works and is implemented are discussed in a future issue, together with details of how you can obtain copies of the software. ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com form the same angle at F, they If you imagine that you are are similar triangles. This sitting in your chair facing the means that the ratio of any two QL screen, then the orientation sides, is the same for both commands are described as triangles. So for the point x,y follows. Entering a negative Y Yi value causes the camera to turn towards the right, up through D D +Z1 the specified angle, entering a which means that negative pitch value causes the DxYi_ yi camera to turn upwards through Y the specified angle and entering D +Z1 1 +(z1/0 a negative roll value causes the A similar argument applies to camera to rotate along its axis of the x coordinate of any point on viewing in a clockwise direction the screen. So that you can see through the specified angle. P=1x,y) for a given point x,y,z in the 3D Positive values will turn the and i=xCose.ySine a.e., its projection, i,j is given by camera in the j = -xSine.yCose opposite x direction. i- If you adjust the 1 + (z /n) orientation and not the position then it is as and if the camera has not moved, but

. Y simply turned about its centre.

This final transformation allows Octahedron example points to be plotted on the QL's screen, and if the points are To give you an idea of how the joined in accordance with the program works, try the octa- 3D a.e. data -base, a line or 'wire hedron example, firstly using frame' image in perspective will the SETUP facility to describe the octahedron to Fig. 2. Translation of (ij) spective points. Returning to be produced on the screen. the 3D a.e. data -base. coordinate system (a) and the imaginary camera, you can Because 'wire frame' images rotation of the (ij) see that it is merely a screen and are used, it is coordinate system (b). an imaginary focal point. Software for wire -frame drawings not essential to describe every face Coordinates of the camera are of the body, We are now in a position to i.e. you make a cube from just simply the coordinates of the examine some preliminary screen. four wire frame squares, the two software for producing wire remaining faces appear auto- The diagram also shows that frame images of objects of any matically. This can be a the screen is located at the great Vertex x y z shape provided that they can be origin of saving for many bodies, the 1 0 1 its own coordinate constructed from 0 straight lines. octahedron being the case in 2 0 system. It is in relation -1 0 to this Program List 1, to be shown in point. 3 0 0 -1 system that all points in the 3D the next article, is modular 4 1 0 In fact only four faces of the 0 a.e. are specified, after the which allows the important 5 0 0 1 aforementioned transforma- octahedron need be described to 6 0 1 0 functions and procedures to be give tions are carried out. a correct image. Try used in any program. The main entering the following data, Table 1. Example coordinates. Now, x and y coordinates of a role of this program is a to allow after first entering ERASE and point projected onto a screen objects to be set up in the 3D SETUP. The octahedron has four have to be determined, say a.e., and to view those objects polygons, 1, 2, 3 and 4. Polygon xl,y1,z1. From Fig. 3 you can see from desired position. When 1 has vertices 1, 4 and 5, that a triangle is formed by 'viewing', you should try to polygon 2 has vertices 1, 2 and F,(xi,yi,zi) and the z axis. It prevent the camera from 3, polygon 3 has vertices 4, 3 should also be evident that a turning its back on the scene, and 6 and polygon 4 has vertices Fig. 3. Principle of triangle is formed by points F, since this program does not perspective (x,y) and the origin. 5, 2 and 6. make any attempt to prevent Table one gives transformation. Since both of these triangles the x,y and z transformation of invisible coordinates of each vertex. points. When you have finished des- The first procedure, SETUP, cribing the body, the program allows a rudimentary method of will end and tell you so. You defining the 3D a.e. data -hase. should now enter VIEW. The next major procedure, VIEW places the camera at the origin of the 3D a.e. The image from this position is then drawn, and the user prompted for camera commands. Entering positive x, y and z values causes the camera to move right, up or forward respectively by the desired amount. Negative values will Software for producing wire - move the camera in the opposite frame images will be presented L__ sense. in the next section. 38 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com LANGREX SUPPLIES LTD Climax House, Fallsbrook Rd., Streatham, London SW16 6ED RST Tel: 01-677 2424 Telex: 946 08 RST 1,1I

_17 i, ;a_' 10 vn71 SEMICONDUCTORS , I;;1' ;5 ,:: II 111 26 10I1( 22_61) I.2, /I\5(11 0.14 091 , AAI I( 1,4 l,-1 I)218 tI1\ll I01 '. ()t 2N1X21 171 .'I4l I I /T\5I4 212 01 I)\1 14I 1l \X4 2n \I Illc 1n 28 III 204 \1866 1(K 5 .'14X I 115 /I\511 AA/I3 211 11l t)\(2 11\81 28 11I -1 la 2.9 ,. 11I429A \1WH III 2_18 _ I 521 116 /I\5511 , 41 f1 1.28 11 (I( 15 T11i11A I AA/IS Il 10 I( 214 l, l {)111' \X7 1 211,1< lr N414 '219 - AA/17 II 10 21' ,111' t)120 I 5 4I \M 111 '_ (I( 16 II'11A \19M 1 ll ,1416 A('l07 I5' ',II, 1- í(21X 1.11' t)1(0 I5, tI1511 8 \U 11115 )(4I 11'1 \ 2.c \4(11x ll2 1 2\4059 3 1 5 5 1 1 5 N4(01 0 5 5 1 ' 1 1 1 1 1 ( 1 2 \ - 43 5 1 1 1 1 1 I ( 1 1 1 1 1 1 1 f 28 C 1.:6 AC 12s I( 1 6 \ ' 1 . 9\ 1 4 X ' 152 111 41 I11144 1 IA N41X12 _ A('1.76 11.15 In154 I(1113 11.16 t II1+2 \11' 104 11-55 fa 0 '\J1WI I 12 111XI1 u 51 I 151 11' 111' 1115 f1.55 IHJ4 II'JIA 2141MI AC'127 0.40 IAISS 11 I(1117 IIIIY IIl'I.4 II 1,1' 0.17 (1C45 11'4'A 42 N43X4 X 1-2_t 11c A('128 11.35 IA156 I( 311X I 0 1154 411, \II'SAIM 2\4,M2_ ,- :169A 1.23 t 1 11'1111 110 \4005 1 1.(2` 047 la 2\412_4 1 154 \ 111 A ( 1 J I 0.35 ;A W62 3C l'_7 1 1 9 1S\14 \II'SA56 'I 115 \4106 :aX4 124 4 11'117 2\3126 AC141K 11.45 3A.\13 ( 128 0.119 1611 \\ 211 \II'tiCOI 1-II ()('2 11( 5. 1r17 375 t ()( "1 11'125 -55,46 2\424n .A('142 0.40 tAXI6 11.6', 11114 166 IS\21 \II'51116 1-11 11'1111 . 109 '9114 410 0.45 t 167 I I I I M 1.65 \II'SI56 l'1 II( '4 '\42XX 1.1' At-142K 1C1(17 0 1 - 45 . .30 176 11.15 11 111 t 171 145 !IV'7941X1K ( 7S 111111 XA \44 11 Al I. 1118 0 1. NI "5 0-111 91< I111 111 ()('6 IPI1 .JB .-I,xl 1 ) 3.IN ,N14(x1 I AC187 1.15 ( 119 ( I I7- \K1411 45 (1.11 '816 ).2 11'115 1 '401 1 t \441 I ACINB 0.35 IlII1 ' t(1'3' l'n C10 fl1`05 I._'ll M.1401 (SC O( XI 11'117 148 0.04 "07 1._2_ A(Y17 225 3C114 ( 1 CC 2 50 I79 I.tO i1206 12 \K1404 4.x 2\441, ,I 1. 11'140 1.X5 11.IU 5'424 11_ 2\54, ACY18 1.55 1( 115 1 34 2 5( t IX 110 Il 2118 _2.IX1 ()chi/ 1.85 21 0.12 .' 2\54'S 1l'141 \7425 , C 1.61 t In1 25 8111X1 0.42 (C45 0CX2 A('Y19 1.80 1( 116 119

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A2291 1610 51-94 2.1(1 015f11 PC97 75 Q10-3000A 5280F 22.51 4\150A 61.(0 6DQ60 175 21346 A2426 1500 '195 5.99 0/32 4.1+ PC900 .75 495.00 1283CC 12.00 451501) 5610 6FA8 3,110 20E6 -.288CC 198 2.10 G/33 PCC84 50 Q10620 32.70 A2521 25.10 17.50 6E0X 150 2BH7 6.10 -1181 21X0 (i/)4 PCC85 .50 RIO 6.00 513254\I 1510 -n0, A23XX1 15.011 .810F 35.48 6EW6 25 2097 , u, 4,<1, 95184 2.10 0/37 'S PCC88 .00 R17 3.00 11 51125551 35,0 A3343 4510 .A52 32.25 6F6 1'110 115631 1 5(-12 160.10 300 JLI '.18145 12.(X1 K 36 550 PCC89 .75 RIB 3.00 A/31 2.75 -A76 2.50 5 - 6121 1.60 2E11 TT 2800 .I-01155 1501 5066 15.10 PCCI89 2.50 RIO 9.24 \('l. 51010 511801- 165000 A/41 2.60 -..ABC80 1.25 ,' 61-28 1.60 2E14 65.(X, n 11,r '1191 1.75 KT77Gold PCC805 1.60 R20 2.50 \ 5R41.1" 550 BK448 114.91 -.AC91 3.50 6133 33.50 2E1 17050 705 -K91/ 1.5(1 1i0n 1210 PCC806 1.60 R63.1250 59.50 " 0.4c, 3.01 11K484 155,35 -.AF42 2.50 14.00 9114 27.10 132 2.50 2-00 RG3-250A32.68 514013 2.50 Mil -44 2.91 BSOO 58.00 5AF801 2.00 KIXX(iold PCE82 \n. 3,..,, 2.50 61125 275 OHS 47.50 ;1 4.(X1 1 RG3-1250 59.00 1IS810 60.10 -041 4.00 111 1on 201X1 PCF80 2.00 013N 2.75 2409 67.25 1 . :1141111 410 K18461 PCF82 1.50 RG4-1250 61.60 1' 513G7 2.50 095 58,95 1391 1.50 10015 ., OHS 3.00 2.IX1 -'144 -116 2_.sl) K111'62 PCF86 2.50 RG4-3000 99.45 X111-32X111 5/3 4.00 BT17 IX5,(0 13C31 250 614 5.50 11117 2.(X, 141 2.00 2 RR3.250 40,00 XRI-32(XIA 5/40 250 13919 44(15 'BC4I 2.50 KI11(,1 PCF87 2.00 RR3-1250 45.75 SRI 6400 5/40 T 2.50 616 8.93 30C at 2.00 - 12 349.15 '.BCRI 1,50 I42 22.50 (0I5079 1.2.C. PCF200 3.25 0129 311F5 I 61 5.25 SIIE12 65.00 15(1 (.1(11 .2 175 617 4.75 - ,6A 11.9 1.25 -1.81 M801511) X 5 PCF201 3,25 BT69 354.81 BC90 61E6 7.50 3011I 2 1.38 -...-9 5,03 6.()0 MNO81 SILO 6.00 9 D11211 19 64114 1.75 13T95 129.9 -0F80 1.50 'L83 PCF801 2.50 5130P 6.00 Y 13124 40 3.00 6K4N 2.50 3041-12 1.80 ,v6 17,59 -13F83 .1 04 2 25 M8082 96" PCF802 2.50 6AII' C'BI.31 40 1,75 6K6GT 2.75 30FL14 2.(X2 2.50 1.86 275 M8083 10 2' PCF80$ 1.70 STV280-40 /81130 MAC' 1.00 C'1.33 4,(X FBF89 1.50 3041 14.00 /259 _ ' 4-25 6K7 3.00 1,50 -96, 3.50 3.25 1 6AF3A CYJI 31 BL31 10.00 .191 M8091 PCF806 1.70 5.19 STV280-80 7.141081 6A07 101 61(8 3.00 301 15 2.00 605 2.2, CIK 2(1.0 -C'90 1.25 '1.91 18181196 6.n PCF808 1.70 11, 6K1)6 7.00 301.17 200 6421 4.50 195 2.(0 X 21,00 /111020 6A H6 5.00 ('7A 22.1x .1791 8.00 M8097 PCL82 2.00 3(1.1X) S3141 5.00 /(011(121 6AK5 5,99 61 6(I 3.00 30174 2.511 6(157 12.25 1 156 M8098 I 1' PCL83 3.00 SOJA 22.10 C'92 1.75 2.50 8.511 SU42 10.00 Z111(122 6AK6 2.5p 616GA 3.50 30019 6058, 12.34 DA41 25.1X -('157 462.00 '.1.3MI M8099 X0 PCL84 2.00 5 61.6(iC 30191.1 3.00 11.500 3.(X1 MXI1X) 1111'1 PCL85 2.50 TD03.10 35.00 7. 511021 641 1.50 5-75 6159 6.00 DA42 18 .7 'CC33 4.50 35.00 /511040 61 6GT 1.00 30E9 14 1.80 6061 6.00 51.509 10.00 MOI 16 10 -' PCL86 2.50 TD03-10F 6AM4 4.(0 DAI'91 1.7. -.CC35 4,50 1.80 13.00 T15 50.00 /511041 I" 6.4515 4.69 617 2.50 30171.15 6161 3.75 13A196 1.7- .CC40 5.50 -1.X21 (018137 12' PCL805/85 2.50 TT21 37.50 Z(011142 1- 6AM6 6112 6N 217 2.50 35394 1.10 61(0 10.25 DET22 35.00 .C'C81 1.75 (1.822 13.97 118140 6.0 PD500 6.00 . 51X5 1.50 El. 1,80 19.00 M8I41 PE06-40N 45.00 9922 37.50 11330,1 64N5 4.75 6N3P 2.50 6067 1175 DET24 49,01 CC82 1,75 3.00 7581 6.05 1-M34 8.00 M8142 TTI00 60.00 1824 651198 3.50 6N7 6172 6.00 1)191 175 '.CC83 1.75 PFL200 2.50 TY2-125 78,75 1B35A 3.25 6P225 4.00 75C'1 4.50 611811 14.01 1 (01911 2,50 (019144 PL36 2,50 6405 1)1596 1.7 .CC84 1,75 85A1 7.50 215.L81 1M81 2.50 518149 PLXI 1,75 104400 88.20 i063 6AS6 11.66 6Q7 ).75 6974, DK9I 175 ('C85 1.75 3.25 X5A2 6,45 F5184 210 (018161 4.C' PLBIA 2.00 TY4-500 115.50 1R5 6407(i 0.75 6K7 60970 200.00 1)1092 210 -('C86 2.50 9101.5 20.00 1\1X5 018162 995-500 236.00 110< 6A16 1.25 6RHH8 6KN8 6146A 12101 1)096 3.50 275 11., 01.82 1.50 175 'CC88 10,0(11 90AV 20.00 2.50 0 T56-800 231.00 I 6ÁUSCi1 5.10 614613 12.05 CC89 2.00 LMN7 110163 PL83 2.50 1 1)1.92 2.(0 6SA7 3.00 90C'1 6.00 615913 19.0' LN32 25,00 610191 S PL84 2.0) 9945000A 2AS15 64,116 2.50 1)L94 175 ('C9I 8.93 6SC7 275 91X'G 14.54 6189 9.51' F.N91 6,50 (013195 11.1' 0L504 5 2,50 50009 20 '39A 6455(',A 4.511 1)1.96 175 'C'C189 2.10 90CV 15.45 1N92 6.96 618196 -''1 PL508 5.50 TY6-500013 2(43 6A56 1.50 6S137 2-511 6201 I1.41, DISIO 14.00 CC807 1.75 2U.00 395.00 21)21 6S17 3.00 92AG 200(1 6442 CC808 I5951 275 5182114 PL509 6.80 6A\5(3 r 3.10 DI.SIS 12.511 3100 TY6-5000W 6017 3.25 92AV 20.10 0110 8.0( EY81 2.511 818212 II C PL519 6.00 2(26 ' 6117 1.25 01016 12.50 -.CF80 1,50 7.50 9541 8.45 11'83 2.511 518221 . PL801 1,50 446.00 2142 ' 610 3.25 6S67 68830 12.55 DI.SI9 12.50 -C'F82 1.50 15002 6.50 7-5, 1.954 9,24 016224 PL802 6.00 TY7-6000A 2155 2 6856 1.50 601,701 3.(0 6973 UM70 2.00 -CF86 2.50 8.15 4 ., 2170A 1,' 613A' 5.00 6SN7GT 3.00 15083 7025 3.30 2.00 -CH35 7.00 19N6 175 (010225 PY33 2.50 579.00 DM71 TY7-6000W 21700 6SQ7 3.40 151(32 3.25 70274 80 (9N8 175 5162431 I PY81 1.50 613A8A 401 1)M161 4.75 CH42 3,50 6.00 E1'510A 3.10 511)2911 11`,1,1 PY82 1.50 57900 2R25 611(4 100 6SR7 4.00 1511'4 7551 6.2 1)587 1.50 -CU8I 3.00 TZ40 25.00 34007 11' 1.50 6SS7 275 211 15.00 7586 IS.IX 5C'H83 2.50 EY8(112 1.75 Mt '14 P083 1.25 6E1E6 I30802 1.50 6135Ci 3,50 723A8 125,00 U18,20 3.50 350X1/ I 3 6006 2.50 7587 23-(0 E551. 5001 :CH84 2.50 E/,15 I.75 11\119 PY88 2.00 . U19 13.75 1A5 61116 225 6U8A 2.'5 803 25.00 76W 5600 CL80 1.50 E/40 1.50 \I\123 PY500A 4.00 (80CC 150) 4._5 805 45.00 1-/41 2.511 61\145 PY800 1,50 U25 250 31324 II 6804 4-519 6V6IT 7868 6.10 1580K15 11.2' .CL8I 1,75 U26 2.50 11128 654 3.1X1 807 3.75 7895 121x1 1.1.80 1511 (015150 II ' PY801 1.50 68I.6 8510 E01)1 14,14 CL82 1.50 L/.81 l.5(1 151\152 QF451 U37 12.00 31329 6017GT 4.511 655119 175 811A 18.37 8068 16. 11.73 -('1.83 3.00 1. 1' 82.50 (801 1.25 7137 2_.50 812A 15.00 8136 2.50 L"/.91 J.(X) 11\161 1. QQV02-6 35.70 UABC80 JB2411A1 ' 613116 115.1X1 (MCC X.IXI -C'L84 1.50 vavlc ..C'LBS 3.50 51511,1 QQ903-10 26.25 UAF42 2.50 1024151 613N6 2.01 '(3 4.00 811 6550 8417 6181 EXIT. 13.27 I,50 )394-500 3.50 UB41 3.00 3(71 6BQ70 3.511 7('6 2.50 833A 193.16 11042 11.5C E82C'C' 8.10 .CL86 1.75 IW4810 M\IM 52 QQV03-20A UBC4T 2.25 1(24 (43R7 600 7H7 4.00 866A 20.111 18045 10.49 MCC' 840 117A 5.00 C137114 35.00 01\166 147.10 48.38 UBF89 1.50 4 1.50 7R7 4.25 872A 20.10 IR(Mb I1.55 139 2.75 G55I10 1210 M\168 SII.I0 QQV06-40A 3(\11X14 68118A E86C 8.25 1.75 7S7 150 9t1 6.00 0180.261 17.511 15 (Ki 46.00 UCC84 3(29 4' 6857 600 E101C 1,25 .F40 5.00 571 7Y4 2 25 93I4 18.50 G240.2D 12.1X1 QQZ06-405 UCC85 1,X5 3ti4 61306 6.00 E88('(' 10.33 'F41 3.50 O0 0400.1K 17.50 OA3 62,20 UFC80 2,00 354 175 680'7 I.50 7/4 2.10 1624 401 Tc502J E9001,'C 947 142 4,50 250 UCH42 2.50 4-65A 61.00 5.1X1 12AU8 5.10 1625 3.50 :1-50 2,50 GN4 9.10 ()04 6.10 QU37 12.50 685767 F\-1.0n1pmen, F.90F 9,91 2.50 I.5(1 2050 7.50 4,I9,00 4,35 QV03-12Q903-12 6.80 4-1254 61.00 613/6 '_75 12AT6 4CX2500 8.50 E91H 6.25 T54 5.00 li!44A 082 UCL82 1.75 6C'4 1-25 12477 1.75 4212E 300.00 :3-55 3.50 0N44 9.00 0133 2.50 QV04-7 3.50 ('\' Des wes (92(9' 8.75 UCL83 2.75 12A1.16 2.50 42120 300.10 -F80 1.75 G016 16.10 1)C'2 4.35 QQ907-50 76.65 6C064 2.50 lar8c+lock+ (99E 9.10 5.00 5544 III"X6 0T1C 251X1 2-.511 QV08-100197,40 6CD6GA Prices on 1130L INSU FR3 4.00 O(1 :1185 175 GIL 50 20.00 41rPli.alion Ci1151 211. / 4 "4199 2.25 7483 11.42 74110 LSO 74156 1' 4, 4,A570 2.15 1 INTEGRATED CIRCUITS 7484 11.72 74120 /175 74159 1.]5 BASES CRTs 5ADP1 55.101 1f1.1X1 VCR5170 7486 11.54 74121 0.54 ]4110 I.'_0 4A630S 1.75 5(P1 IO.IXI 7400 0.16 74411 U.16 3.00 V(RSI'(' Ie00 072 74122 070 74172 44700 8.50 7416 7490 401 2API 5(PIA 40.00 7400 0.35 00 7.641 0.48 74123 13A480Q .50 10(0 unskilled 7491 (1.16 0.60 74177 0.72 2101 9.00 51'I5A 15.00 74(12 0.76 74I7 048 7432 1.25 (RT+0.Ae15 7492 0.54 74125 0.60 BAS_2lX) .5(1 0.411 1320 0.4ö 74174 0X1 J13P1 20.00 5L'P7 251X1 PrieeSOn 74112 0.3fi 7450 11.30 NA530 .511 Skirled 0.50 7493 0.53 'Jl'_6 a54 74175 .019 It]G 1DP1 5.(0 DG75 63.32 ]401 0.36 7422 11.76 1451 U.Jf1 aPOliea0011 7494 II.7N 741_2N 0.55 NA55(M) - B9AUnxk'rlcd 58.07 7423 74176 (0 11':GI I(1(0 DC/7-31 74(M 0.42 (1.16 7453 0.1(1 BA56X) - 04( I,(.50eke,+ 7495 11.65 74136 0.70 741X0 .48 1FP7 6,00 1)67-32 58.0] 74U5 (C42 7425 0.;6 7354 (1.311 BARSJ -5 Tc0a5 7496 U.6, 74141 11 46 74190 89A Skirted 0.50 3(iPl 6.00 T3(ì7-36 h5,00 ]411fi (1.38 7425 O.Jb 0.311 lowpr0111e 7460 7497 1.90 74111 1.30 74191 13A7(X) B9D 055 CIPO 8.00 DH7.91 56.83 7428 11.36 X pin Illp ]3117 0.55 7470 0.40 21 F1A7Ul 74100 O.X4 '4145 0.72 74192 - In) Octal 0.40 IJP2 0.011 1)H7-11 7410 0.36 .0 III-12 14 pin 111p 74U8 0-36 7472 0.30 BA75lX.) .50 I.octal 0.53 7411J7 0.36 24147 1,50 74193 1.6 111'S I0.00 VCRI18 12.10 - 74(9 U.lfi 7432 C1.16 7473 11.16 16 pin 111p 741(9 (1.54 '4118 1.40 74194 It PAN00 .00 N00 (slur base 3K1'1 15,00 VCRIJXA 12.50 7411 7433 055 7474 11.36 11.30 7411(1 114N 74150 I.MI 74195 07_ BA920 - 2l0 3RPI 35.00 V('R119A Xl0 7411 0.4(1 1337 ll.lM1 7475 0.65 74111 0.51 74151 0.36 74196 1.1X 00990 5() Valve screening JWPI 20,00 1142 741R (1.16 7476 ll.tö 10 ]412 74116 1.50 71154 1.40 74197 CO270) cans all siXC,a4o 7419 0. 36 15X 7413 0,36 1480 0.1- 3 74118 1_211 74155 11.61 74198 2.20 TCA760A ) I Terms of business CWO. Postage and packing valves and semiconducto s 50p per order. CRTs £1.50. Prices excluding VAT, add 15%9' Telephone 01-677 2424/7 Price ruling at time of despatch. Telex 946708 In some cases prices of Mollard and USA valves will be higher than those advertised. Prices correct when going to press. E. & O. E. Account facilities available to approved companies with minimum order charge £10. Carriage and packing £1.50 on credit orders. Over 10,000 types of valves, tubes and semiconductors in stock. Quotations for any types not listed. S.A.E. Open to callers Monday-Friday 9 a.m.-5 p.m. WW1 CIRCLE 25 FOR FURTHER DETAILS. www.americanradiohistory.com SUPER HY -LIGHT STROBE KIT VARIABLE VOLTAGE TRANSFORMERS Superior Quality Precision Made DeRgned for Disco. theatrical uses, etc. Approx 16 Ioules. Adjustable speed. Price £45 [2 p&p (Total roc. INPUT 230, 240V a.c 50/60 OUTPUT n-2M1[79v NEW POWER RHEOSTATS, VAT .OS, reflector price 2 O lib Max .50 £34 Case and f 17 12 p&p (total Inc VAT E22.00 E21.95).Foolscap SAE for further details including Hy Light and 0 KVA Zl/tA Max New ceramic construction. heavy duty brus h R Industrial Strobe Kits 1KVA 5A Max E31.00 i414111*- assembly, continuously ratedr 2KVA 10A Max E45.00 25 WATT YInRSiShcly ate 250/300/5lKl/1kQ E59.00 ULTRA VIOLET BLACK LIGHT 3KVA 15A Max 1 5k4 C4.25 + 30p p&p ((5.23 mcl. VAT). E105.00 SKVA 25A Max 50 WATT 25012 C6.50 + á0p P&P ((5.06 mcl VAT). FLUORESCENT TUBES E190.00 4n 40 10KVA 50A Max 100 WATT 1 /5/10/25/50/1 00/250/500/1k4/ 1.ák4 /2 580/3 5k S2 wan [IOM 1[1200 me VATI E285.00 2h 10 wan E7 44 [I 15 p&p 1090 Inc VAL 15KVA 75A Max (10.25 + 75p pSp (12.65 Ince VAT)

All V V Ts and 1 I &n 15 wan ES .10 75p p&p 051 Inc VAT, plus carriage VAT Black Silver Skirted Knob calibrated in Nos 9.1i Tin dia brass bush I3in 10 wan 14.40 75o p&p 0.46 Inc. VAT 3 -PHASE VARIABLE VOLTAGE TRANSFORMERS Ideal for above Rheostas 30p ea i VAT IAn 8 wan 0.60 50p p&p 10.71 me VAh Dual input 200.240V or 380.415V Star connected INSULATED TESTERS 90 6 wan E3.111 50p p&p I01.62 ins VATI NEW! 3KVA. 6KVA. 10KVA. available. Phone for details. test to I E E Spec. Rugged metal construction ten 4 wan £3N 50p p&p IE412 one VATI Comprehensive range of TRANSFORMERS L.T. ISOLATION & AUTO suitable for bench or field work onstant speed 230V AC Ballast Kit for either 6m. ihn or 12ín tubes ES. 50 nAp 55p clutch Size L Bin. W 4m. H 11696 inc VATI 1110-240V) Either cased with American socket and mains lead o -open 6m weight 6Ib 500V. 300 megohms E49 p&p 12 1E58.65 Ince For 13in. & 11in. Tubes E6 p&p 75p 1E7.76 Inc. VATI frame type available for immediate delivery. Leaflet on request VAT 11000V 1000MO f55 . p&p 1.21E65.55 Ince For 12V DC op. 12in & 13in. tubes only (5.50 p&p 75p Inc. (f7.11 SPECIAL OFFER: Brand new Safety Isolation VATI SAE for leaflet VATI Transformers. Primary 0- 104 -11- 129 -V. r 175 WAIT SELF -BALLASTED BLACK LIGHT MERCURY BULBS. 0- 104 -110 -120V. Secondary 0 -104- 110 -120V. L T TRANSFORMERS Available for either B C or E S fitting, price f 14 p &p E 1 25 (total Inc VAT £17.54) 0-104-110-120V. 2KVA @ E40.00. 3KVA @ (60.00. "Special 08m" 0 -6 3V 0.6.3V at 10 Amp 112V 0 10 Amp or 6V al 20 AnipI Price E9.00 - 400W UV LAMP & BALLAST complete - E56.80 o £3.50169.35 in- 4KVA with 0 -110V. Secondary only @ E80.00 +Car- p&p £2.00 inclusive of VAT (12.65 N M S cl VATI riage and VAT. 'Phone for further details. GEARED MOTORS 400W UV LAMP only, E28 + p &p E 2.501E35.981ncl VATI SINGLE DIAPHRAGM COMPRESSOR NMS 5 rpm 140V AC MI by Caner. E6.ß El p &p 10.11 inc VATI N M S 20 rpm I I5V AC Synchronous. torque apprur 90ib in £20. i f1 p&p ITotal Inc Ma. 20 PSI One CFM approx 240 volts A C £18 I2p &p 1E23 inc VATI ROBOT ENTHUSIASTS VAT [27.) N M S ESCAP precision Swiss -made vonless rotor, 6V DC geared Motor TRANSFORMER 2400 operation. 0.15 £200 p&p ITotal Inc VAT (12.021 EPROM ERASURE KIT rpm Torque 200 In reversible 1 h p 110V AC Price with 70 -1 gearbox. 6V DC - 16 r.p.m. 3V- 8r.p.m. amazing 1f 800 £9.50. p&p CI BO Why waste money, Build your own EPROM ERASURE for e Inc power. no bad current, only 10 ma. approx. Size: 4 x 2 )cm. Ex. (Total VAT £12961 fraction the once a made-up unit kit pans less equipment. tested and guaranteed. ONLY E4.50 o 50p p&p (total of of Complete of Suitable TRANSFORMER for 2301100 AC operation Price OA p&p Et 40 12. Tube. nc. VAT £5.751. se to include 8 watt 2537 Angst. Ballast unit, pair of (Total Inc VAT E7.591 N M S tri pin leads, Neon indicator, safety microswitch, on/ON switch 3$.6 rpm GEARED MOTORS Torque 35lb. in. reversible 115V AC Inc. start SOU° STATE RELAY and circuit. capacity Price E11.55 p&p £2.00 (Total Inc. VAT £15.581. N.M.S. LESS CASE. Price E13.60 i 75p p&p (Total Inc VAT (16.501. Single make will switch up to 250v. A.C. 10 amps. Recommended Suitable TRANSFORMER 230V AC Operation Price C5.20 n 50p p&p IC6.51 nc1. in is operating voltage 8.26V. 0 C but will work el less man 5V D.C. silent, con Warning: Tube used this circuit highly dangerous to the VATI eyes Unit must be fined in suitable case tactless. opto isolated. Suitable for use with T.T.L. Logic for switching mains 100.7 rpm 651b in reversible 115 volt AC price E30.00 p&p [4.50 voltage. Mfr. by Teledyne. Offered at fraction of mfrs. price'. [3.00 45p (Total Inc. VAT (39.681 P&p trot* inc. VAT £3.971. N.M.S. 12V D.C. BILGE PUMPS Suitable TRRNSFORNER for above Eli p &p El 501£1271 inc VAT) 400 G.P.H. 15h. head. 3amp, 0400 E1.00 p&p MCRO-SWITCH (' 57 rpm 24011 h p I12 continuously rated REVERSIBLE 50Ibm manul by Button type 10amp do contacts. E6.90 for 10 post paid. inc. VAT. 1E10.35 inc. VATI aaaRjyy- Wynstruments New Ideal for garage doors. curtains etc ONLY 02.10 . 700 G.P.H. 10h. head 3.5emp. (11.50 El 50 p&p f2 00 VORTEX BLOWER SUCTION UNIT p&p tincl VAT £16.161. inclusive capacitor & 1E14.95 Inc VATI Powerful multi -stage dynamically balanced totally enclosed rotors, I v 71 rpm Torque 1Sb in reversible t 19h h p 110V AC 1750 G.P.H. 15ft. head, 9amp. (15.00 Lt.75 p&p motor Price 0.51 El 80 11/2in. inlet and outlet, 110V AC. F22.00. Switchable transformer for 1E1926 inc. VATI p&p (Total me VAT (12.111 240V AC 0.00 p&p f3.00 - total ä4.50 inc. VAT. 1 ti Suitable TRANSFORMER tor 230.240V AC operation Pore 020 p&p El 40 VBL4 BLOWER I Total inc VAT [7.561 N M S CENTRIFUGAL FROM STOCK AT PRICES 240V AC powerful 1/50 h.p. 0.23A motor £16.00 + £2.00 p&p - total 24400211 rpt 015/m MI by Carter. Es-equip. tested 1/.00 f 1.50 p&p (Total inc. VAT 423.00. N.M.S. THAT DEFY COMPETITION inc VAT [11.93). AC GEARED MOTORS C F BLOWERS Zr24W AC SYNCHRONOUS. 2 rpm 6 rpm. 6 rev per day Any type RIO . 50p 12/24V DC CENTRIFUGAL BLOWER I DC MOTORS SMALL AC CAPACITORS p&p (Total inc VAT 0.101 0.4A producing 30 cu. ft. £7.50 + fi 00 p&p - MICROSWITCHES STROBE KITS total inc VAT 13.75. N.M S RELAYS FLASHTUBES CHECK METER COOLING or EXTRACTOR FAN REED SWITCHES CONTACTORS 231/240 AC 40 amp. fully reconditioned £7.54 C1 75 p&p (Total inc. VAT SOLENOIDS AC or D.0 SYNCHRONOUS 010.64) Quiet smooth running. Size 4314x 43/4 x11/2. PROGRAMME TIMERS MOTORS Supplied for 240V AC operation. Price £5.75 WADE RANGE OF XENON TUBES SANGAMO WESTON TIME SWITCH o f 1 p &p - total inc. VAT £7.75 N.M.S. III _ WRITE/PHONE N YOUR ENOU66ES Type 5211 200/290 A.C. 2 on /2oft every 24 hours. 20 amps contacts with ! override switch. Diameter 4-x3 Price inc. VAT 6 240V. A.C. SOLENOID VALVE. Designed for Air /Gas at 09.51. [1.50 póp (12.65 A.C. CAPACITOR. 161.iF 900V. A.C. 50 /60Hz. Ideal P &P). Also available with solar dia RAT. Other types ayadable from stock 0.7. Water 5 psi. Inlet -outlet I ". Forged-brass body. power factor correction, etc. 91 x 6 x 41 ins. Wt. 7 ¡Kg. N.M.S. New Manufacturers' Surplus Manui Dewreswitch Asco Price: E6.50 + f 1.00 p &p. Reconditioned Price: (12.00 + 13.00 p&p. 1E17.25 incl. VAT). N.M.S. RAT and tested If 8.63 incl. VAT) N.M.S. roods normally despatched wnnln 7 days Ample parking space TRADING Personal callers only Open Saturdays Showroom open SERVICE CO 9 Little Newport Street 57 BRIDGMAN ROAD; CHISWICK, LONDON W4 5BB. Tel: 01 -995 1560 Monday-Friday Tendon WC0H 7JJ ACCOUNT CUSTOMERS MIN. ORDER 110 Tel: 01- 437 0576 CIRCLE 22 FOR FURTHER DETAILS. PINEAPPLE SOFTWARE Programs for the BBC model 'B' with disc drive with FREE updating service on all software ARE YOU GETTING THE MOST FROM YOUR SEL DOT MATRIX PRINTER AND DISC DRIVE? DIAGRAM is a new program which really exploits the full potential of the BBC micro and will enable you to obtain printouts of a size and quality previously unobtainable from your system.

FEATURES

Draw diagrams, schematics, plans etc., in AT any aspect ration, e.g. 10*3, 2 *12 screens. ACCeSS any part of the diagram rapidly by entering an index name, e.g. TR6, RS etc., to display a Specific section of the diagram, and then scroll around to any other part of the diagram using the cursor keys.

Up to 128 Icons may be predefined for each diagram, e.g. Translstcrs, reVIstos etc., in full mode 0 definition, up to 32 pixels horizontally by 24 vertically.

SPEED Hard copy printouts in varying print sizes up to 18 mode 0 screens on an A4 size sheet.

NAGRAM SOFTWARE compatible with most dot matrix printers. MARCONI TRACKER BALL 125 60 Many other features including, SHectable PLUSf display colours, comprehensive line drawing incluars Iton 4tInatter Software yPe am) 03,807 05( vi6en order, facilItIES, TAB settings, etc.

MARCONI TRACKER BALL AND The latest version of DIAGRAM is now fully compatible with Marconi Tracker TO BE CRYSTAL CLEAR ICON ARTMASTER PLUS the Ball, which allows 'scrolling' Of the screen and DIAGRAM SOFTWARE many of the Editing features to be carried Out using the tracker ball.

£76.50 DIAGRAM is supplied in an attractive hard AEL CRYSTALS LTD PLUS VAT P&P £1.75 backed disc wallet with keystrip and comprehensive instruction manual. GATWICK HOUSE HORLEY SURREY RH6 9SU ALL ORDERS SENT BY RETURN OF POST TEL: 0293 785353 TELEX: 87116 AERO G 39 Brownlea Gardens, Seven Kings, Ilford, Essex 1C3 9NL CAA approved ¡a Tel 01- 5991476 CIRCLE 21 FOR FURTHER DETAILS. CIRCLE 31 FOR FURTHER DETAILS.

40 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com PR OBA BL Y THE ONL YDE VEL OPMENT SYSTEM

YOU'LL EVER NEED...... runs FLEX, a powerful, well supported operating system; and gives access to a vast range of high level languages, Compilers and Cross Assemblers including: Z8, 8048, TMS7000, TMS320, 6800, 6802, VMS earn 6808, 6801, 6803, 6301, 6805, 6502, 8085, 8080, Z80, 68000. Its attractive modular design allows for easy expansion as your demands increase. The complete system comprises: a 6809 Industrial Controller with 64K DRAM, battery backup, and Real Time Calendar Clock. the new CMS Floppy Disc Controller, supporting up to three Quad Density 3.5* or 5.25 Disc Drives. two Pined as standard the recently introduced 40/80 Column Teletext Card with Centronics Printer Port and Serial Communications to an IBM style keyboard. All housed in an extremely rugged Industrial rack. This has to be the Best Value For Money on the MDS market today! Cambridge \I, Microprocessor Systems Limited 44a Hobson Street, Cambridge CBI 1NL. e 0223 -324141

CIRCLE 6a FOR FURTHER DETAILS.

THREE INTO ONE Will GO- WITH THE CROIECH 3132 1 1 SCOPE: 2 Active Component Comparator DC - 20MHz Bandwidth (for checking Transistors, diodes and 2mV /div Sensitvity I.C.'s etc) 4Ons - 0.2s /div Sweep Test Voltage: 8.6Vrms (28mA) 14 Trigger Functions Including active TV trigger on line & frame. All for the price of a scope at 3 Triple Output DC Source £285* +5V (1 A); -ve grounded (Excluding Delivery and VAT) 12V (200mA) Common Floating Correct at time of going to press Crotech Instruments Limited 3 2 Stephenson Road, St. Ives, Huntingdon, Cambs. PE17 4WJ Telephone: (0480) 301818

Also available from Audio Electronics & Henrys CIRCLE 71 FOR FURTHER DETAILS. SATELLITE TELEVISION METER PROBLEMS? Buy direct from the manufacturers, low cost full band satellite TV systems. Write or telephone for details, or call in at our factory showroom. Agents and Distributors required. NETWORK SATELLITE SYSTEMS LTD 137 Standard Ranges in a variety of sizes and stylings available for 10 -14 days delivery. Other Ranges and special scales can be Units 7 -8 made to order. Newburn Bridge Industrial Estate Full Information from: HARRIS ELECTRONICS (London) Hartlepool, Cleveland TS25 1 UB 138 GRAY'S INN ROAD, W.C.1 Phone: 01- 837 7937 Tel: 0429 869366 Telex: 892301 HARTRO G CIRCLE 23 FOR FURTHER DETAILS. CIRCLE 29 FOR FURTHER DE'T'AILS.

ELECTRONICS 8t WIRELESS WORLD MAY 1986 41

www.americanradiohistory.com RAEDEK ELECTRONICS Telex2No 312242 SERVING THE COMMUNICATIONS AND ELECTRONICS INDUSTRIES MIDTLX G. 102 PRIORY ROAD, SCRIBERS LANE, HALL GREEN, BIRMINGHAM, B28 OTB. ENGLAND. TRANSISTORS: VALVES:

TVPE. LIST. TYPE: LIST: TYPE. LIST. TYPE. LIST TYPE: LIST: TYPE LIST TYPE LIST: £ r £ £ £ 2N3375 10.90 2SC1978 6 40 AH211A 137.50 EF94 200 0A3 2.50 6AU5GT 3 70 813 3000 2N3553 1.60 2SC2053 080 AH2511 90 00 EF95 1 60 082 2 50 6A28 3 80 934 1800 2N3632 1295 2SC2237 6.00 AH2532 3150 EF183 1 90 063 2.50 6BA6 1 50 935 41 20 2N3733 1295 2SC2287 9.60 BTS 52 50 EF184 1 80 OC3 2.50 6BE6 1 95 2050 480 2N3866 1.20 2SC2290 20.00 BT58 5250 EK90 1 40 2C39Á 3990 68H6 215 2050A 480 8T17 14200 2N4416 0.75 MRF240 20.70 EL34 390 2C39WA 4200 68J6 2.00 5544 8100 BT1 7A 130.00 EL36 230 2D21 200 6BK4C 4.50 5545 9500 2N4427 1 40 MRF245 33.00 BT95 12500 EL84 1 60 2E26 750 68N8 350 5557 24 50 2N5090 1090 MRF247 33.30 C3J 3000 EL86 2.10 2K25 11400 68Z6 2.50 5559 5250 2N5109 1.95 MRF433 9.00 C3JA 3000 EL519 770 3-4002 7800 6C4 1 95 5727 295 2N5160 300 MRF449A 1015 E55L 56.00 EL803S 995 3 -5002 8500 6CB6A 1 80 5867A 140 00 2N5589 7.60 MRF450 11.50 E8OCC 1400 EL821 13.75 3828 15.00 6CJ3 2.30 5879 6.15 2N5590 7.90 MRF450A 1 3.80 E8OL 2100 EN32 1625 3C45 24.50 6CW4 630 5965 220 2N5591 9 50 MRF454 17.25 E88CC 390 EN91 200 3CX100A5 35.00 6DC6 245 5991 3200 2N5641 6.95 M R F454A 17.25 E9OCC 7.50 EZ80 1 60 4 -65A 52.50 6E5 4.20 6130 24 50 2N5642 9.30 MRF455 16.50 E130L 2125 EZ81 1.50 4 -125A 6000 6EA8 2 25 6146A 900 2N5643 11.85 MRF458 17.20 E891 1 35 EZ90 1 50 4 -250A 76.00 6GK6 2 50 61468 900 2N5913 2.50 MRF475 2.30 EBC91 110 FG17 24.50 4-400A 80.00 6HF5 4.25 6360A 4.95 EBF89 1 35 FG105 160 00 4-40013 80 00 6HS6 3 95 6550A 7.25 2N5944 7.85 MRF476 2.15 EC90 1 25 GXU1 t5.00 4-400C 80.00 6J86A 4 20 68838 870 2N5945 10.10 MRF644 22.50 ECC32 325 GXU4 4500 4B32 30.50 6JE6C 6.25 6973 3.95 2N5946 1080 MRF646 27.00 ECC81 1 60 GZ34 210 4C35A t3500 6J56C 470 7027A 650 2N6080 6.65 MRF648 32.70 ECC82 t 60 KT66 900 4CX250B EK7 250 7199 420 2N6081 8.40 MRF901 2.75 ECC83 1 .60 KT77 8.75 EIM; AMP 5500 6K11 2 25 7247 3.20 2N6082 10.50 SD1013 9.75 ECC85 1 85 KT88 24 95 4CX250B 6KD6 5.90 7262A 26.00 2N6083 11.20 SD1019 -STUD 23.10 ECC88 200 ML8536 27500 NAT 4800 6KD8 200 7360 1220 2N6084 12.00 SD1019-5 22.80 ECC91 200 ML8741 265.00 4CX350A 87 00 6L6GC 390 7586 11 .50 2SC1729 12.50 3.10 ECC189 200 NL SERIES 4X150A 3370 6LQ6 625 7587 3500 2SC1945 3.45 SD1134-1 2.25 ECF80 1 50 OQV02-6 2200 5ÁR4 210 6011 225 7591A 4.65 ECF86 1 65 QQV03-10 5.30 5AS4A 2 10 6SL7GT 2.25 7815AL GE 48.00 2SC1946A 16.00 SD1136 1 1 90 ECF801 I 80 QV03-12 700 5R4GYA 3 50 6SN7GTB 3 05 7815R 53.00 2SC1947 8.50 SD1143 940 ECH81 230 OY3-65 5750 2 10 6U8A 2.00 8122 101.00 2SC1969 1.80 SD1219 14.70 ECL82 1 90 QY3-125 63.00 5V4GA 2.50 12AT6 1 50 8906AL 55.00 1 .40 10.95 2SC1970 SD1272 ECL86 1 60 QY4 -250 69.80 6AH6 230 12AU6 1 70 15082 6 50 2SC1971 3.50 SD1278 13.75 EF80 1 70 RG1-240A 10.00 6AK5W 250 12AV6 200 572B 52 00 2SC1972 9.50 EF85 300 904-3000 9000 6AK6 1.95 12BA6 1 80 807 2 90 INDUCTION AND DIELECTRIC HEATING SPARES EF86 230 XG 1 2500 5250 6AL5W 1.80 12BA7 2.35 810 7500 EF89 230 XG5-500 24 50 6A05A 1 75 128E6 2 00 812A 3685 EF91 2.95 XR1-3200 72.50 6AQ5W 1 80 128Y7A 2.70 WE ALSO SUPPLY INCL. EF92 220 XR1 -6400 120.00 6AS6 240 12BZ6 3 70 EIMAC TUBES AND EF93 1 50 0A2 200 6AS7G 4 30 12DW7 3 75 CERAMIC CAPACITORS SOLID STATE RECTIFIERS ACCESSORIES VACUUM CAPACITORS RECTIFIER VALVES 1000's of VALVES TRANSISTORS/IC'S IN STOCK. PLEASE ENQUIRE ON TYPES NOT LISTED PRICES GRID LAMPS OSCILLATOR VALVES SERVICE AIDS I - CORRECT AT TIME HEATSINK COMP. 1100g) - 1.50 OF GOING TO PRESS CARBON FREE HOSE COOLING FANS /FILTERS CONTACT CLEANER - 1.00 SILICONE GREASE - 1.50 WATER FLOW SWITCHES etc. etc. TERMS - PLEASE ADD f 1.00 FREEZE IT AEROSOL - 1.25 LARGE RANGE OF SOLDERING IRONS AND ACCESSORIES P &P AND VAT @ 15% to orders. CIRCLE 36 FOR IURTHER DET:IILS. Toroidal & E.I. Transformers As manufacturers we are able to offer a range of quality toroidal and laminated transformers at highly competative prices Quantity Prices and delivery on request.

MAIL Order Price List (prices inclusive of VAT & Postage) E.I. transformers clam 6VA 2.90, 8VA 3.40, 12VA 4.20, 15VA 4.75, ': I UK's WIDEST Toroidal transformers 25VA 5.40, 50VA 6.50, Range of low cost 15VA 7.95, 30VÁ 9.18, Avila 50VA 10.16, 80VA 11.36, FMS Available i- the-6e following robotic & equipment 12.07, 160VA 14.20, voltages: 20, 2, O 225VA 15.51m 300VA 17.04, 0-15, 20 -0 -20, 25-0-25.25 -0 -25. Primary 240 500VA 22.10, 625VA 24.66, volt. j 750VA 28.75, 1000VA 44.82. from stock -the Printed circuit tie Cybernetic followingfallowing voltages 6-0-6,6 -0 -6, 9 -0 -9, mounting Applications 12 -0 -12, 15 -0-15, transformers. (E.I.) WORKCELL COMPONENTS MI 18 22 -0 -22, 25 -0 -25, 30-0 -30, -0 -18, 3VÁ 2.38, 6VA 2.99, 35-0-35, 40-0-40, 45 -0 -45, 50 -0 -50, indexing table ' West Portway Ind. Est. 8VA 3.75, 12VA 4.66. ¡ill 110, 220, 240 (max 10amp) Available in the folowing expandable conveyor Andover, Hants primary 240 volt. 15-0 - sensors gauges Also available 1k2, 1k5, 2k, 2k5, voltage: 6-0 -6, 9 -0 -9, 12 -0-12, SP103WW 15, 20 -0 -20. Primary 240 volt. etc 3k. Prices on request. Portable isolating . transformers NAIAD Input 240 output 110V. 9 rating contin.84. l Auto transformers 500 /750VA 53.84, water hydraulic/ 240 volt input 115 volt a 1000/1500VA 72.57, DC servo/ USA socket outlets pneumatic (fully shrouded) 1500/2500VA 85.54. 150VA 11.00, 300VA 15.00. Input 240 output 240 500VA 27.00, 1000VA 34.00, 250 /400VA 57.40, 1500VA 48.00. 2000VA 53.00 500 /750VA 65.25. 500 gm SERPENT I, II at 500mm 2Kgat400or650mm with see through perspex AIR Air Link Transformers. cylinders Unit 6, The Maltings, Station Road, LINK Sawbridgeworth, Herts. Tel: 0279 -724425

CIRCLE 15 FOR FURTHER DETAILS. CIRCLE 44 FOR FURTHER DETAILS.

42 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com Fibre Optics '86 If you don't think fibre optics is for you this event should convince you otherwise.

The Fibre Optics '86 Exhibi- K -Tech claim a typical loss New at Electro- Optics, tion, held in hall D of the Earls of less than a decibel for all Dia- Court exhibition centre, is part mond SA single -mode connec- Brighton of British Electronics Week tors, using 6/125µm fibre, in- As well as standard single consisting of four exhibitions cluding new types MMS40 to mode optical fibres York Ven- taking place simultaneously at BT spec and MMS11 the first tures and Special Products of Earls Court and Olympia. It to be approved to DIN stan- Chandler's Ford make both aims to bring together leading dard. Also new are optical at- ultralow and high birefingent fibres. The high birefringent manufacturers of fibre optic tenuators for single to multi - components and systems to mode and vice versa use with type avoids polarization noise Data link modules show their latest products to a values from 2.5 to 30dB, and and signal fading in fibre typical of those currently 'broadly based audience of several tool sets. EWW 301 gyroscopes and other in- available for point -to- engineers, managers and com- for further details. terferometric sensors, for links point use and local area mercial staff', and includes to polarization- sensitive devices networks. This Plessey Kaptron, a new principal for and for coherent communica- pair can operate up to lasers, local area networks and Centronic Sales, specialise in optical sensors. It is open from tion. York's fibre has a beat 125Mbit /s in either NRZ fibre optic components and length of less than 2mm: beat or Manchester biphase 28 April to 1 May in hall D of specialist test gear including the Earls Court exhibition cen- length is a measure of polariza- encoding (50Mbit /s) at Polytrope, an IBM PC- tion holding ability. (Any phase tre - a different venue from controlled automatic fibre distances of up to 2km. last year's Olympia - and a list difference between the two or- alignment equipment. EWW thogonal modes gives rise to IBM PC- controlled fibre of exhibitors accompanies our 302 for further details. stand plan. beats.) Ultra -low birefringence optic alignment aid by For about a £100 a day an ac- BICC Optical Components is useful in devices where the Polytrope (Centronic companying conference, held at Unit at Prescot are to introduce polarization plays an important Sales). the nearby London West Hotel a series of test equipment, the 29 April to 1 May, discusses re- first of which is a stabilized cent developments in fibre com- light source for accurate on -site ponents and applications in attenuation measurements. both sensing and communica- The emitter is a 1300nm edge - tions. If you are unable to at- emitting 1.e.d. whose output is tend you will be able to buy a chopped at 270Hz (the normal set of conference papers after power meter frequency) but the event (only abstracts are which can be externally available at the event from, modulated or operated c.w. strangely, publishers in the We're told the price of £3,450 is USA - SPIE *), and if you want about half that of its (laser - copies of previous conference based) competition. EWW for papers (all British) you'll have further details. to buy them from America. To Fused couplers for fibre help newcomers get down to sizes of 62.5 and 85/125µm are basics there are tutorial ses- now made by ADC Fiber Optics sions on 'Basic fibre optics' (28 in addition to existing types for April), and 'Optical fibre sensor 50/125, 100 /140µm graded - technology' (29 April), both of index and 100/140, 200/240µm which cost around £100 but for step -index fibre. EWW 304 companies wishing to acquire for further details. the basics quickly this is pro- Belling and Lee Intec fibre bably a cost -effective way. components, modules and con- (There is also 'Business oppor- nectors are to be distributed by tunities in fibre optics', which Cirkit Distribution following an the brochure shows as a listing agreement signed at FO '86. of applications, and 'Industrial applications of expert systems', Cossor's optical time domain which connection with fibre op- relectometers will be marketed tics isn't at all clear.) in the USA by Wilcom Pro- ducts, a subsidiary of com- PO Box 10, Bellingham, Washington, munications co. Plantronics 98227 -0010, USA. Inc. ELECTRONICS & WIRELESS WORLD MAY 1986 43

www.americanradiohistory.com FIBRE OPTICS 4iNi\i,"`"v EARL S COURT - HALL D - LEVEL 2 29 APRIL - 1 MAY 1986 FIRST AID

- -11 12 -I ;14 78^ 79,, 15 10 16 9 17 75 19 8 18 r , SOUTH 7 81 \( }` RESTAURANT 50 64¡ 21 7 84 1 66 UP TO '29' Ll./_i L L68_J ILLUSTRATORS BAR

3 2' 23 1 25 1 /0'1 // Denotes Site Only 24 i, Ma 22;

Organised by Evan Steadman Services Ltd. WEST w The Hub, Emson Close, Saffron Walden, BROMPTON . Essex CB101HL. ENTRANCE Tel: 0799 26699 Telex: 81653 7tro:I---r LIFT LIFT PRESS Ir »t J orq_232

Product Focom Systems 61 S Exhibitor Stand code Fotec - see Centronic Accris Electronics 45 Fujitsu Microelectronics 66 C ADC Europe 24 C Galvoptics 68 C,I AG Electro- Optics 52 C GEC Optical Fibres 70 F General Optronics 42 All- Inspection NDT 36 I Ando - see Aspen Grass Valley Group 35 Anritsu Europe 47 TM GTE Slyvania 63 Aspen Electronics 40 TM,C Hall and Watts 67 Hirschmann see Electroustic Bausch & Lomb UK 51 I - Belling Lee Intec 79 C,S Honeywell Control Systems 62 C,S Holtek Optronics 14 Bentham Instruments 41 I BICC Group 48 F,S,TM ICI Stratos C Buehler 81 M Instruments Technology 2 I Burleigh Instruments 16 C Kendal Hyde 71 M C Centronic Sales 75 C,TM K -Tech Micro Precision 80 Centronic 75 C Lambda Photometrics 4 TM,I Codenoll - see Thorn EMI Laser Lines 31 C,TM,I,S Lasertron 21 C Comtec Cable Associates 73 I Cossor Electronics 26 TM Leetec 22 C 46 TM,I Datarange Communications 43 S E.Leitz (Instruments) Lightwave 74 Delta Controls 83 I M Ealing Electro- Optics 30 C,I Logitech 39 C Electroustic 76 S Melles Griot (UK) 50 C Engis 89 M Micron Semiconductor 28 Epitaxx Inc 32 C Microwave Systems 49 C Fibre Data 44 C,F Mullard 88 National Physical Lab 57 Fibre Optic Links 23 S C Fibre Optic Systems 37 S NEC Electronics (UK) 60 NKT (UK) 29 S

4 -1 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com role for example in electric or peripheral equipment to allow magnetic sensors. In ordinary measurement of chromatic single -mode fibres birefr- dispersion of single -mode ingence is generally sensitive to fibres. The multidimensional temperature, pressure and detectors are able to record vibration making calibration of time, position or wavelength, polarization difficult. York's and light intensity, and allow fibre, made by a preform spinn- time -resolved spectroscopy up ing process patented at the to a wavelength of 1.6µm. University of Southampton, can Observations of long wave have zero birefringence in near- phenomena have been impossi- ly all situations; linear retar- ble with conventional streak dance is less than a degree, cameras because of the low effi- with no variation of polarization ciency of the photocathode in with temperature. EWW 305 the range 1.3 to 1.6µm. The for further details. streak unit, type C1587, uses a synchroscan tube in which a Radiall fibre optics connec- sinusoidal sweep voltage aplied tors are now available through to the tube's deflection plates is Stabilized modulated light source for Norbain Electro- Optics, follow- synchronized with repetitive ing a distribution agreement attenuation measurement (BICC). light pulses, for example from a with the French manufacturer. dye laser. Integration of streak Covered are the SMA style con- images occurs on the phosphor nectors for five sizes of p.c.s. screen or by direct readout. multimode fibre, the new FMA Hakuto International, EWW types, and the very low loss Op- 306 for further details. taball range also suitable for Gallium aluminium arsenide monomode fibre. Emitting and emitters and a p -i -n photodetec- photodiodes from RCA, TRW, tor are newly available from Siemens, and EC &G's Vactec Motorola distrubutors Gothic were newly shown at Brighton Crellon. Designated type but a surprise announcement MFOE3200 and 3201 and was the exclusive rental agree- MFOD3100, the devices are ment with STC for its range for housed in a new low -cost rugg- time domain reflectometers. ed plastics- capped package that Temporal disperser is the fits standard device recep- name Hamamatsu give to their tacles. The two emitters launch 30GHz long wavelength optical 10 and 20µW into 100µm fibre oscilloscope. Based on a and are 850nm diodes with a sychronized streak camera, it bandwidth (60MHz) claimed to connects with a conventional be higher than any other emitter in the price range. Enter camera - TV or still - and SMA -style connectors, in which the end surface temporal analyser for real time EWW 307 for further often referred to as the is polished to a convex operation together with other details. `industry standard' of spherical shape, said connectors, are frequent- to "drastically reduce" Norbain Electro Optics 11 C ly used in data transfer connection and return Oceonics SPL 84 S applications. The range of loss compared to the Optical Fibres 56 F Radiall SMA types similarly constructed FC Optical Publishing Co 6 now available from Nor - connectors. Optilas 18 C bain, Optronics 69 C together with the EWW 308 (Radiall) Oriel Scientific 53 C,I Optaball range which EWW 309 (Walmore). Philips Kommunikations 85 have average losses as Photon Control 33 low as 0.35dB. Pirelli General 54 F New ceramic -ferrule Plessey Optoelectronics 25 C SMA types are added Prior Scientific Instruments 55 to the Optical Fibre Radiall Microwave Components 38 C Technologies range from RCA 34 C Walmore, as are two new REL 78 S Rofin -Sinar Laser 5 TM biconical types with Sira 3 TM ceramic capillary. Special Gas Controls 87 C,F Multimode version is Spectrolab 15 field -installable using pro- Stratos - see ICI cedures for Dorran Sumitomo Electric Europe 77 C,F Photonics connectors, System Donner - see Thorn EMI with which they are TBL Fibre Optics Group 64 F mateable. Telecommun- Thorn EMI Measurements 90 C,S ciation systems usually Vickers Instruments 1 TM Walmore Electronics 82 C,S use flat contact (FC) con- Product codes: connectors /components - C; fibres /cables - F; test nectors such as Sieko's and measurement - TM; systems - S; optical instrumentation - I; NTT type. Their latest coating and lapping - M. development is the point contact (PC) type, bottom, ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com by John Lidgey SENSITIVITY ANALYSIS - WHAT IS IT AND WHAT CAN IT DO? Whilst generally used for filter analysis, the sensitivity analysis is just as valid in many other branches of electronics.

Sensitivity analysis is a tion. To illustrate the meaning Y X aY ax a1nX aY following Sx fairly simple mathe- of SX consider the Y ax a1nX aY ax matical technique that is example. most often used in electronics as Suppose X represents tem- an aid to help establish whether perature, T, and Y represents a Sx'= = (5) alnX a particular active filter will per- resistor value R, the value of form to the required specifica- which is inversely proportional To illustrate the value of this tion, and if so, what tolerance to temperature, i.e. R = A /T, formulation of SI, consider the and temperature coefficient the where A is a constant. Then us- following example. Suppose components should have. ing equation 2 gives Y = AXP, where A and P are not Though quite useful in this functions of X, then from equa- R T2 a(A.T -) context, sensitivity analysis is a ST tion 5 very useful technique that may A aT Y AxP a1nAXP a1nA be applied to many circuit pro- ST= -1. Sx Sx blems and the results obtained a1nX alnX are valuable to the circuit Using the informal definition in designer. (1), the fact that ST= 1 means a1nX Sx = +P.-= P. that if the temperature were to a1nX increase by 1% then the Definition resistance would decrease by This is the proof of the first iden- The informal (not absolutely about 1 %. As can be verified us- tity shown in the Appendix, and precise) definition of the sen- ing equation 2, if the resistor the others can be verified in a sitivity function is happened to be inversely pro- similar way. The identities ease portional to T4 then the value of the complexity of evaluating Sx Y AY AX ST = 4 and then the change of using the definition of (2). Sx _ R would be four times as great. Y X (1) Application to negative feedback and it is the ratio of the normalized variation of parameter Mathematical relationships systems Y to the normalized variation of A very helpful relationship in Negative feedback results in a parameter X. If the variation AX simplifying calculations of sen- lower overall system gain and is infinitely small, then sitivity values is derivet neit. closed -loop gain in much less Suppose Z is defined by the sensitive to open -loop amplifier Y X aY Z = classical Sx = expression X = cz or lnX. performance. This Y aX (2) Differentiating gives result can be simply shown by Dr F. J. Lidgey is Principal Lecturer in evaluating the sensitivity of the Electronics, Oxford Polytechnic Equation 2 is the formal defini- ax ax z closed -loop gain to the open - - =e loop gain. If we use the symbol az alnx AF for the feedback gain and A or for the open -loop gain with ß for ax the feedback factor, then the _X (3) standard relationship between alnX these parameters is Similarly A AF (6) aY (1 + ßA) Y. (4) A alnY a(1+ßA) Rewriting equation 2 using 3 SAAF A(1+ßA) and 4 A aA 46 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com 1

(1 +OA) Introducing the SI58 bus SArA -A (7) R 0 Simpler The closed -loop gain is almost communications the same as the inverse of the feedback network gain, provid- between ed that the open -loop gain is computers. much larger than the closed - notoriously loop gain. This fact is clear from The difficult art of getting computers equation 6, and from equation 7 this makes and their peripherals to talk to one another is about to AF become a great deal easier, S = - -0. The table shows that the SX Clearly if Q is 10 say, this gives a with the launch of the S5/8 values are reasonable with no value of SQ = 27.3. serial interface. Turn now to a standard op -amp high sensitivity effects evident. This is intolerably high as a non -inverting amplifier with In fact, they are all within the +1% change in K results in After extensive preparatory work by closed -loop voltage gain of range -1 to +1. Other con- about 27% change in Q! Having Government bodies and straints permitting, if RI were discovered this most disastrous British industry, a detailed V° AF= (1 +R2 /R1), set to equal R2, then feature for moderately high specification of S5/8 has VIN values of Q, the designer would where R2 and R1 are the feed- just been published by the SR -0-SR2 be well advised to abandon this back resistors linking the output circuit completely and seek a British Standards and Institution. to the op -amp with the inverting replacement to achieve the input terminal and the inverting The new arrangement is SA , _ S desired band -pass response. input terminal and earth R2 certain to receive a warm respectively. If the sensitivity tabulation welcome from anyone who To establish the sensitivity of resulted in any values being five Appendix has to struggle with RS232 and its endless permu- AF to each of the resistors more it would be wise to con- Useful identities for without much effort and no dif- sider discarding the circuit in sensitivity analysis tations of data format and ferentation, use the identities favour of an alternative yielding electrical connections. For shown in the Appendix: lower sensitivity to componnent Definition with S5/8, incompatibility variation. has been designed out. SAF AF -1 X aY alnY - =SR F. (8) The second -order active SX All physical and elec- AF band -pass filter shown above Y ax alnX trical aspects of S5/8 (it stands for serial, 5 volt, Clearly if AF > 1 then the sen- has the characteristics: 1. Y = AXP, where A and P are not sitivity values given in equation functions of X 8 -pin) are defined in the centre frequency published proposals: as far 8 approach unity in magnitude. Y Sx -P as the user is concerned, it On the face of it none of these 1 ./2 results are particularly surpris- is a `plug and run' interface. °27r R.0 2. sY=_SIY There is only one kind of ing nor startling. However, if x x the values obtained were not centre frequency gain interconnecting cable and small but yielded figures of 10 or only one permissible sig- 3. SX'Y2=SX,+SX2 nalling format and data more we might well be alarmed A°- and as this would suggest a large SX, rate. (4 -K) 4. SVY2 - SX2 change of the circuit parameter But S5/8 offers further quality factory benefits: in place of the Y as a result of a change in cir- 1 cuit component X. This does oc- ,/2 5. SN=-SX costly 25 -way connector, it cur if positive rather than Q- N is based on cheap, compact negativee feedback is used in a 4 -K Y1SX + Y2SX2 eight -pin DIN connectors. 6. SX"Y°= Logic levels particular application. One of the poorest aspects of Y1+Y2 are compatible this particular circuit comes to with 5V c -mos i.cs and are light when evaluating the sen- appropriate for portable Application to active filters sitivity of Q to variations in and other low -power The circuit shown on Page 46 is amplification gain K. It is equipment. of a second -order band -pass relatively easy to show that Already, six manufac- filter and from analysis the cen- turers are using S5 /8 in S1= 2./2.Q -1. their products and many tre frequency fo, the quality factor Q, and the centre frequency more have said they will gain A° are given by the follow- adopt it when it becomes a British Standard. ing expression: X. R2 C1 R1 CZ We hope to publish 1 1 shortly an article giving full f° - Szo %2 v2 -'4 1/2 details of S5/8. But in the Za VC1R1C2R2 R meantime, the specification A Rt S o 2 +1 -1 1 1- is available under the BSI C1 R1 X (R1+ (RI + R2) A°- R2) reference number DD 153. C (R1+R2) +R2 .0,1 t BSI Sales Department, SX /2-(Ri. 2 (R1+R2) Linford Wood, Milton Q= 1 R1R2 JC1/C2 Keynes MK14 6LE. (R1+R2) ELECTRONICS & WIRELESS WORLD MAY 1986 -1;

www.americanradiohistory.com INDUSTRIAL CONTROL with BBC BASIC The EuroBEEB SYSTEM offers a fast, modular solution for the engineer designing intelligent control and monitoring systems. Typical cost-effective applications include PLANT MONITORING AUTOMATED TESTING PROCESS CONTROL FACTORY SUPERVISION REMOTE DATA AQUISITION INTELLIGENT INSTRUMENTATION Real -Time BASIC allows a powerful system to be configured in the minimum time. This event driven, multi- tasking extension to BBC BASIC allows the user to control the CUBE range of Eurocard expansion modules simply and efficiently. BBC Micro or IBM PC can provide low cost development support, data analysis and display facilities for EuroBEEB. MODULAR EUROCARD EXPANSION - CONTROL NET -an intelligent distributed Rugged stand -alone systems can provides high -voltage, high- current system for remote monitoring and control be configured by adding disk, video

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CIRCLE 63 FOR FURTHER DETAILS.

20 PIN DUAL PPM 5 IN LINE * VICCOM MODEM # M,t w.,M Il eu a Mlr. r as. ` ñ i e; MA w HYBRID .ÓirtrbAM sat t .MMMAMAM-R4lM NW * am 1 M MN AFn an1a b.Bl> MO .b. 4M< .,u . nre t n.M MM Consumption 3mA. Fully meets BS5428 -9 á ba.M, LWtlA HIN Hui .¡. MI MM -vV.c 4 6 MIft. a'5 -35V .e

12 7

VICCOM MODEM (UNIVERSAL) EUROPEAN CCITTT STANDARD PPM 5 For all computers such as: CCITT V.21 ORI. 300 BD F. Duplex seta IBM, Apple, BBC, Commodore, CCITT V.21 ANS. 300 BD F. Duplex IOF spectrum etc £110.00 CCITT V.23 600 BD H. Duplex CCITT V.23 1200 BD H. Duplex OPTIONS CCITT V.23 75/1200 BD F. Duplex RS 232 interface cable (F) for (Videotex -Viditel, Prestel) IBM PC £8.00 CCITT V.23 1200/75 BD F. Duplex RS 232 interface calbe (M) for (Videotex /viewdata Host) SURREY ELECTRONICS LTD. Apple II £8.00 USA BELL STANDARD Interface cable for BBC £5.60 Bell 103 ORI. 300 BD F. Buplex The Forge, Lucks Green, Cranleigh, Surrey GU6 7BG Interface cable for spectrum Bell 103 ANS. 300 BD F. Duplex Tel: 0483 275997 (with interface I) £6.70 Bell 202 1200 BD H. Duplex VICCOM MODEM £79.00 VI DEOTEXNI EW DATA For CBM -64 or other Commodore Telecommunication softwares: comptuers with user -port, and for * Top Spectrum£16.00 the SPECTRUM. tz For CBM 64 £25.00 For BBC £39.00 r with most Viewdata * Work For IBM IN VIEW OF THE EXTREMELY RAPID CHANGE TAKING and VIP Terminal :r PC £75.00 Softwares For bullet, Morrow MD11, Program (CBM -64) Northstar advantage £70.00 PLACE IN THE ELECTRONICS INDUSTRY, LARGE QUANTI- Expandable with a power unit for other computers. VIDEOTEX /VIEWDATA REDUNDANT. WE ARE CBM- 64 /VICCOM INTERFACE Host Softwares: TIES OF COMPONENTS BECOME CABLE £8.00 * Datatel for CBM 64 £75.00 SPECTRUM /VICCOM Poseidon for BBC £170.00 CASH PURCHASERS OF SUCH MATERIALS AND WOULD INTERFACE CARD & CABLE, Note: these softwares work with AND TERMINAL /VIEWDATA AUTO ANSWER /DIAL CARD APPRECIATE A TELEPHONE CALL OR A LIST IF AVAILABLE. SOFTWARE £20.00 ,ñ in the U.K. UNIT £26.00 Modems for use POWER should be approved by British WE PAY TOP PRICES AND COLLECT. Telecom OPTION t: DEALERS REQUESTED Auto answer/auto dial card (This card works with VIP Terminal COMPUTER SOURCE R. Henson Ltd. Program for CBM -64 and the BRAHMSLAAN 129 videotex host softwares) £35.00 21 Lodge Lane, N. Finchley, London, N.12. 5 mins. from Tally Ho corner * 6 months guarantee 2625 BV DELFT Approved by PTT (Dutch * HOLLAND, Telephone 01 445 2713/0749 Telephone Company) TEL 015 -613195 CIRCLE 41 FOR FURTHER DETAILS. CIRCLE 72 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com TRANSFORMERS EX-STOCK INVERTERS 12124V DC to 240V AC MAINS ISOLATORS 50125V or 25-0-25V 30115V or 15.0.15V 100W £65.95 PrilSec 1200x2 2.25V Tap Secs Volts 2.15V Tap Secs. Volts 250W £208.00 160.1000VA Tap Secs) available 5, 7, 8, 10, 13, available 3. 4, 5, 6, 8, 9, 500W £301.00 VA Price P &P 15, 17. 20, 25, 30, 33,40. 10, 12, 15, 18, 20, 24. 1000W £424.00 20 6.72 2.18 20 -0 -20 or 25-0-25V 25, 27, 30 or 15-0 -15V 2000W £636.00 Keithleybl3QA 60 10.96 2.31 &I3á 50V 25V Price P &P 30V 15V Price P &P 4000W £1215.20

100 12.79 2.59 0.5 1 4.77 1.76 0.5 1 3.68 1.41 CONSTANT VOLTAGE 200 18.12 3.10 1 2 5.80 1.90 1 2 4.99 1.70 TRANSFORMERS 1% 250 21.91 3.24 2 A 4 10.32 2.20 2 4 8.07 1.92 VOA orerrvu ewnrarnran Spike-tree 350 27.10 3.40 3 M 6 11.95 2.25 3 6 9.35 2.10 stable mains q5Ó ik 158.0001Á 500 33.76 3.66 4 P 8 16.34 2.58 4 A 8 11.16 2.20 f 5 00V Á __ 6201.93 1000 61.22 4.62 6 S 12 20.80 2.79 5 M 10 13.80 2.31 5000 6201.93 1500 78.97 5.95 8 16 29.42 3.15 6 P 12 15.62 2.55 2KVA £380.50 2000 95.01 6.36 10 20 34.91 3.60 8 S 16 20.90 2 60 3000 133.23 OA 12 24 41.78 3.80 10 20 24.11 2.84 3KVA 2'95 4KUA .. 1`6951.05 6000 284.66 OA 12 24 26.73 6173.00 115 or 240V sec only. 60130V or 30-030V 15 30 30.75 3.51 SKVA 61470.00 6KVA .. E 1697.75 4001440 to 2001240 CT Pri2.120V.2x30VTap 20 40 41.16 5.95 Secs. Volts available 10KVA ... .. 63480.00 I60-1000VA Tap Secs) AUTOS VA Price P &P 6. 8. 10, 12, 16, 18, 20, AVOs & MEGGERS 105, 115, 220, 230, 240V 60 10.98 2.31 24, 30. 36, 40, 48, 60, 8 MK611atestl 6140.10 For step -up or down 100 12.79 2.59 24-0-24 or 30. 30V. TT169 Transistor VA Price P &P 200 18.12 60V 30V Price P &P Test 668.40 3.10 80 5.58 250 21.91 3.24 0.5 1 5.42 1.85 Megger Batt 680.30 150 8.09 1.85 1 2 8.26 1.91 11155 Megger Crank E132.50 350 27.10 3.40 250 9.85 500 2 4 10.62 2.20 Full range AVOs, Meggers 33.76 3.66 500 15.35 2.68 3 A 6 15.35 2.34 Fluke, Edgecumbe 1000 61.22 4.62 1000 27.42 125 2000 95.01 4 M 8 17.50 2.55 6.36 1500 32.54 3.68 WW MODEM PROJECT 3000 133.23 OA 5 P 10 22.12 2.78 2000 49.66 4,62 Transformers 71, T2 6000 284.66 0A 6 S 12 25.24 3.02 3000 82.74 5.72 67.59 pair inc VAT, P &P 8 16 35.48 3.65 24)12V or 12-O-12V 5000 125.08 00 10 20 41.30 3.99 METAL OXIDE 1W 2x12V Secs. pri. 240V 7500 193.06 OA 12 24 47.40 4.65 5% RESISTORS .601100 12V 24V Price P &P 10KVA 228.12 OA 12, 20, 33, 47, 75, 390, 430, 0 .5 3.68 1.0 EQUIPMENT TYPES CASED AUTOS 510fí, 560, 1k, lkl, 1k3, 1 .05 3.68 1.60 sac V Amp Price P &P 240V Cable Input 1k6, 1k8, 2k, 3k, 2 1 4.90 1.70 on 3-0 3V 0.2 3.26 .96 115V USA socket outlets 3k9, 15k, 16k, 24k, 27k, 4 2 5.66 6.2 142 3.12 1.30 VA Price P &P 39k, 56k, 82k, 100k, 6 A 3 8.87 2.05 0.0.9 0.1 2.72 .96 20 7.94 1.76 110k, 120k, 130k, 150k, 8 M 4 10.37 2.10 9.2 0.33.2 2.53 .96 2001, 220k, 270k, 300k. 10 P 5 11.34 2.10 8.9.2 5.2 3.53 1.30 80 10.79 1.87 O9.2 1A2 4.48 2.31 150 10 Selected values mixed 12 S 6 12.57 2.25 13.97 2.20 15.2 2.2 2.53 .96 611100 16 8 14.98 250 17.02 3.02 2.60 12.0-12 .05 3.11 .96 500 27.92 3.19 20 10 20.16 3.04 20.2 15.2 3.65 1.30 BRIDGE RECTIFIERS 1000 30 15 25.06 3.10 1527.2 .5 5.89 1.70 38.97 4.34 1A 400V .32 60 30 51.35 4.90 15 27.2 16 7.06 .50 2000 69.84 5.28 2A 200V .52 83 41 59.13 5.65 0CT.15V .5 2.66 .96 3000 100.25 0A 35A 100V 63.00 0CT -150 4a 2.29 1.06 961480. Pri 12.5A 500V 63.62 2x1200 Also Valve Mains SPECIAL Secs 2 ALSO VARIABLE AUTOS Output &Matching types 0, 210, 240V PRIMARY 60, 72, 84, 96, 360-0-36 14, 8, 0. 8, 14V SEC PLEASE A00 15% VAT TO or 48-0-48V Stock items by return SERVICES 20VA £3.45 .75pp. ALL ITEMS AFTER P &P 72196 361480 Price P&P WINDING 3VA to 15KVA 1 or 3 1 2 10.31 1.99 Plus Toroidals 2 A 4 16.96 2.54 phase BARRIE ELECTRONICS LTD 3 M 6 20.54 2.75 EDUCATIONAL METERS 4 P 8 26.22 2.89 Finger screw terminals Unit 211, Stratford Workshops 5 S 10 37.22 3.70 0-10A or 0 -30V OC Burford Road, London E15 2SP 6 12 46.61 3.99 78x89mm 63.98 each o 8 16 50.85 4.20 50p P&P Tel: 01 -555 0228 (3 lines) CIRCLE 24 FOR FURTHER DETAILS.

'14MULTIVISION FROM [ROBOT] pair of hancts. Ready and willing to give you the accuracy and flexibility you've come to expect from all handheld DMM's. On the one hand, the new 130A has the desigr and performance of our most popular 130 model but with greater basic DVC accuracy - 0.25% and the need to AVAILABLE NOW calibrate only once every two years- all this at nc increase in price. * Four cameras, any type including high quality 1" , into one monitor, recorder, time lapse recorder, microwave or Slow On the other, there is the new unbeatable value 136, Scan system. a high performance full autoranging 41/2 digit DMM * Can be retrofitted into any existing CCTV installation with full permitting precise measurements in 22 ranges of AC /DC

compatibility. No special or additional cabling required. voltage, resistance AC /DC current including l0A capability. * A full picture in each quadrant utilising the full area of the If you could use an extra pairofhands, or would just like camera tube for maximum definition. Individual cameras may to find out about ourcomplete range of DMM's - phone be selected if required. 0 734 861287 or contact a Keithley distributor now. tr Freeze frame, to instantly freeze motion in any quadrant for closer inspection. tr Full alarm facilities including video loss alarm. Cunningly Keithley Instruments Limited freezes the last picture before video is lost and activates the 1 Boulton Road alarm. KEITH LEY Reading Berkshire RG2 ONL Telex 84 704 7 7r Security lockout prevents unauthorised operations of controls. Berkshire (0734) 861287 Glasgow (02367) 28170 Essex (0279) 29522 London (01) 6390155 ROBOT (U.K.) LTD Gwent (0633) 280566 Cleveland (0287) 32397 Building 33, East Midlands Airport Eire (0001) 984147 Hertfordshire (07073) 38623 Castle Donington, Derby DE7 2SA Telephone Derby (0332) 812446, Telex 37522 CIRCLE 17 FOR FURTHER DETAILS. CIRCLE 11 FOR FURTHER DETAILS.

ELECTRONICS & WIRELESS WORLD MAY 1986 49

www.americanradiohistory.com Are you CP/M Plus (vers 3) Developing Systems Consider our modular approach For NASCOM and Gemini computers Nasbus/80 Bus compatible Features: CPU card CP/M 2.2 file compatibility Z80 CPU incorporating memory mapping Banked memory system 64k RAM on board (expandable) Z80 S 10 providing two RS232 channels Fast warm boot from banked memory CTC providing programmable baud rates Faster disk access: - P10 providing parallel/centronics 1/0 Directory hashing, memory cashing, multi sector I/O Parallel keyboard port Better implementation of USER levels VIDEO card (VFC) 80 by 25 line output Greatly extended and user friendly utility commands Fast memory mapped display 20 transient utility commands On board floppy disk controller Includes MAC the DRI assembler Can be used with CPU card under CP/M Multi command entry on single line Available in kit or built and tested Multiple drive searching facility DISK card (MPI) Mixed 3 ", 3.5 ", 5.25 ", 8" drives supported Console redirection SASI Winchester interface Password file protection Z80 S10 providing two serial channels Date and time file stamping CTC providing programmable baud rates Larger disk and file handling RAM card 29 additional BDOS calls 64k to 256k (in 64k steps) Supports 64/32k paging 4k mapping Extended BDOS capability by easily attached RSXs Available in kit or built and tested Winchester, floppy and virtual disk CLOCK card (RTC) Mixed drive /formats Attaches to any Z80 P10 Full source code of BIOS supplied Retains Centronics parallel output PLUS PLUS PLUS II11 1 lmi Battery backup PRICES CPU £230 MPI £185 VFC £199 RAM (64k) £150 Now Only £ 199 RTC £35 RAM (256k) £285 Excluding post and packing and VAT All prices exclude carriage and VAT For further information contact: CONTACT: MAP Systems Ltd ITFP Unit 2 Stoneylands Road, Egham, Surrey Tel: 0784 37674 CIRCLE 22 FOR FURTHER DETAILS. TELESCOPIC Nappy Memories MASTS Part type 1 off 25.99 100 up 4116150ns 1.25 1.15 1.10 416415Ons Not Texas .98 .88 .80 41256150ns 2.50 2.35 2.10 2114 200ns Low Power 1.75 1.60 1.55 6116150 n s 1.45 1.30 1.20 6264 150ns Low Power 2.85 2.55 2.35 i 2716450ns5volt 2.95 2.65 2.45 2732 450ns Intel type 2.75 2.45 2.25 i Pneumatic 2764 250ns Suit BBC 1.90 1.75 1.70 27128 250ns Suit BBC 2.50 2.25 2.05 Hydraulic Ram 27256250ns 3.95 3.75 3.60 Operated i Winch Operated Low profile IC sockets: Pins 8 14 16 18 20 24 28 40 Pence 5 9 10 11 12 15 17 24 Available now - The ROAM BOARD for the BBC Micro. Reads Roms via a Low Insertion Force Socket and saves their contents as files, then reloads a file into its sideways Ram as Alk Alga required. Full details on request. r' v 74LS series TTL, wide stocks at low prices with DIY discounts ttoo o starting at a mix of just 25 pieces. Write or 'phone for list.

Please add 50p post & packing to orders under £15 and VAT to total. o, Access orders by 'phone or mail welcome. Non -Military Government & Educational orders welcome., £15 minimum. Hilomast Ltd HAPPY MEMORIES (WW), THE STREET - HEYBRIDGE - MALDON Newchurch, Kington, ESSEX- CM9 7NB - ENGLAND Herefordshire HR5 3QR. Tel: (054 422) 618 Tel. (0621) 56480 Telex. 995855 CIRCLE 28 FOR FURTHER DETAILS. CIRCLE 40 FOR FURTHER DETAILS. 50 ELECTRONICS & WIRELESS WORLD MAY 198b

www.americanradiohistory.com Timing by remote by Peter Ferris control Contruction, testing and setting up of a versatile Z80 timer that uses coded r.f. bursts through the mains wiring

Vas could be used clock frequency at pin 6 of ICI, largest amplitude, or if they are the board layoutsts are and adjusting Ct1 to trim it to the same, use the one at the not critical; though exactly 1MHz. Note that an lowest frequency. Once the having built the prototype on accurate frequency counter is peak has been found, remove Vero strip- board, I don't recom- necessary for this job; a residual the 1ká1 resistor and reconnect mend it for the processor board. gain or loss of one second per C2Ó6 directly to the neutral The usual anti -static pre- day (which should be achiev- mains wire. Adjust 'set output able), is equivalent to only level' for a peak -to -peak ampli- cautions should be taken with tude of 4 volts. m.o.s. i.cs in As 11.6Hz error in 1MHz. the the system. Table 1 gives the receiver long as a good quality earthed If an accurate counter is not filter frequencies obtained with soldering-iron is used, the only available, all you can do is to various preferred resistor is that needs to be in a socket is adjust the trimmer by trial and values in the filter circuit. Find the eprom (so that the program error until the daily gain or loss the frequency nearest to your measured peak, and use the can be changed). is acceptable. I had to use this ones either side of it for the Assuming all three boards method myself, and it only took carrier frequencies. The fre- have been built, do not connect six tweaks of the trimmer to quencies given are theoretical; them together until the 5 volt reduce the initial error of 18 actual values are likely to be supply rail has been checked. If seconds per day to about two slightly lower due to phase that is o.k., switch off and seconds per week. shifts within the op -amps and connect the processor board. stray capacitance on the Switch on again, and check for a printed-circuit board. Carrier frequencies 601Hz squarewave at inter - Rather than trimming each board connection 16. This indi- To determine the best carrier filter to an accurately defined carrier frequency, it is simpler The author asks us to cates that the c.t.c. is generating frequencies for a particular loca- to build the first receiver using point out two alterations interrupts, and that the pro- tion, the impedance/frequency preferred value components, to the transmitter circuit cessor is servicing them to characteristic of the mains and then trim the carrier fre- on page 67, February multiplex the display. (If the wiring has to be measured. To quencies at the transmitter to issue: the preset squarewave is not there, refer to do this, enable the transmitter match. As long as 1% tolerance potentiometer at Tri the section on fault- finding). by temporarily disconnecting components are used for the should have a 100kohm Next, check that there is a link E between the processor filters, and the same construc- value, not 10k, and a 601Hz rectangular waveform at and transmitter boards (or, if the tion is used for all receivers, the filters should all match each 100nF capacitor, C10, was connection 17, and that its duty- interboard links are made with other without individual omitted between the cycle can be varied between ribbon cable, lift one end of R210 trimming. bases of Tr7 and Tr8. 10% and 90% with the bright- and R213 out of the board). Connect an oscilloscope to the (One constructor found ness control. Connect a 1k12 resistor in series output of IC301 in the receiver. that a 100pF ceramic If all is well, switch off, con- with C206, and monitor the trans- Disable the transmitter, and capacitor connected nect the display/keyboard and mitted signal on the neutral wire adjust 'set Q' (upper) from the between Tr8 and Tr8 bases switch on again. With any luck with an oscilloscope. The clockwise end until the filter cured his 1MHz the first four seven- segment chances are that a large 50Hz stops oscillating. Enable the transmitter, oscillation.) And in the digits will be reading 00:00 and component will prevent proper and adjust 'set off receiver circuit, page 68, all day leds frequency' on the transmitter the will be flashing. triggering of the oscilloscope; if board for maximum amplitude Ci should be returned to This is the clock display, and the so, connect a 10nF capacitor in on the oscilloscope. The other the neutral line, not to the flashing leds indicate that the series with the oscilloscope carrier is selected by earth line. Incidentally, clock needs setting. Set the input, and 7.5k1ì resistor across temporarily connecting a 4.7k0 two of IC8 gates had the clock as described in the Oper- it, to filter out the 50Hz. Now resistor between the base of wrong symbol: the type ation section, and check that it adjust the 'on- frequency' Tr2oi and the 5 volt rail. Trans- number is correct. keeps reasonable time over a potentiometer, and watch for a fer the oscilloscope probe to the The line that leaves the minute (i.e. that it isn't running peak in the output amplitude. out of IC302, and adjust 'set Q' address bus at IC8 on at half or double the proper There should be one somewhere (lower) from the clockwise end until filter page 65 is A2; the rate). between 100 and the stops oscillating. 500kHz, and Then adjust 'set on frequency' brightness control is a The clock accuracy over long its actual frequency can be for maximum amplitude. 47kohm logarithmic periods depends entirely on the measured approximately on the Once the filters have been set potentiometer; and on IC9 crystal oscillator. This can be oscilloscope. If there are two or up, the rest of the circuit can be it is the inverting inputs set by measuring the processor more peaks, use the one with the checked against the waveforms that are grounded. ELECTRONICS & WIRELESS WORLD MAY 1986 51

www.americanradiohistory.com REMOTE TIMER

Tr1 collector to OV. If the 601Hz waveform appears, experiment UNIT CONTROL *5V with the values of C1 and R8; the

I IC13 Pin1 4k7 RECEIVERS aim is to increase the length of 111 BC108 r i the not -reset pulse, because it

I must remain low for some time t 680 after the clock oscillator has started up. As a last resort, wire J Data a reset pushbutton across C1. .5V bus The software can distinguish a 4k7 reset from a power -up, so you 8C108 won't lose your stored timer settings if the button is pushed OE 680 accidentally; though you will clock. oV have to reset the - -T ------J

If all the appliances to be of (February). To do this, recon- other channels. Any missed or Software controlled are in the same nect link E between the pro- wrongly- received codes will The timer's operating program room as the control unit cessor and transmitter boards now be easy to spot by watching occupies the first 2K bytes of (or refit R2 p3 and R213). Put the the receiver led. Don't worry if the processor memory map, i.e. the f.s.k. control unit can is missed, for control unit in Normal (clock an occasional code from 0000 to 07FF. If a 2732 or be dispensed with. display) mode if it isn't already, instance when the fridge motor is the next Instead of IC13 this circuit then press `next step' and `last cuts in and out - that just indi- 2732A eprom used, provides a directly- step' together, which invokes cates that the noise- rejection 2K bytes, from 0800 to OFFF, connected signal to the Test 1 function; the system logic works. But not more than are available for additional operate each opto- coupled transmits the output status two consecutive codes should be functions. switch. word 20 times per second, missed. The 1K byte ram occupies Tables below refer to the making the receiver waveforms When you're convinced that addresses 8000 to 83FF. The readily visible on the oscillo- all the recievers are working stack grows downwards from receiver circuit on page the normal key 68 of the February issue. scope. (This is achieved by correctly, press 807F; it is difficult to predict toggling channel 0's output at to stop the transmissions and because isn't return the control unit to the how far down it grows, 20Hz, so make sure there it depends on exactly when a an appliance plugged in to the clock display. control unit). key is pressed, which key it was, At this stage, it is worth which step routine is imple- checking the duration of the mented, whether another transmitted r.f. burst (the junc- interrupt was being serviced at tion of C301 and R301 is a conven- Fault- finding the time, etc. Running the pro- Table 1 ient place to look. It should be The following is necessarily gram on a simulator, I have only Filter Frequency about 16.5 ms. it doesn't matter only a brief outline of the sort of caught the stack pointer as far resistors (kHz) if the trailing edge judders a likely to be down as 805E, i.e. 17 levels, so as length problems most little, so long the burst 64 levels available it is 3.0k 531 never falls below 15 ms. encountered in a system of this with 3.3k 482 The timing pre -set should be type. It is based on the assump- unlikely ever to run out of ram. 3.6k 442 adjusted to make the trailing tions that all the components Addresses 8080 to 80BF are 3.9k 408 edge of the pulse at IC305 pin 7 have been correctly fitted, and used as a general scratch pad 4.3k 370 coincide with the centre of the that the eprom contains the pub- area and display store. the inter- 4.7k 339 receiver's data bit, in the lished machine code. rupt vectors are also kept here 5.1k 312 waveform at IC o pin 10. To than in rom to allow the 5.6k 284 If there is no 601Hz waveform rather help identify which part of the on interboard connection 16, software to change the function 6.2k 257 waveform corresponds to a - of an interrupt; the Test func- 6.8k 234 particular channel, press the check for a clean 1MHz square 7.5k 212 corresponding timer enable wave on in 6 of the processor tion, for example, operates by 8.2k 194 key, and that channel will be chip. If it isn't there, check the changing the 20Hz interrupt 9.1k 175 toggled at 1Hz. This is also use- 2MHz waveforms at the outputs vector. 10k 159 ful for checking that a receiver of IC8c, d. You may find only one Addresses 8000 to 80DF (32 11k 145 does not respond to changes in of these waveforms present - bytes) are reserved for future 12k 133 adjacent channels. an impossible situation at first use. The hundred timer settings 13k 122 The last check to be made stored in blocks of eight 15k 106 glance. But what is really are with the oscilloscope is to con- happening is that the oscillo- bytes each, from 80E0 to 83FF, 16k 99.5 edge of the firm that the trailing scope probe is adding enough the highest ram address. Table pulse at IC305 9 is well clear pin 3 shows the storage format and of both the channel 7 data bit extra capacitance to make the and the end of the transmission. circuit oscillate when it is the scratchpad allocations. The Table 2 As a final check when the lid applied to one of the outputs, time digits are stored in packed has been fitted to the receiver but not the other. The solution is b.c.d. form in the setting blocks, Channel R319 box, press the up -key (with the to fit a small capacitor (between to use the ram space efficiently. 1 11k control unit in Test 1 mode), to 10 and 30pF) between the In the display blocks, it is more 2 22k invoke Test 2. The system now apparantly working output and important to minimize the exe- 3 33k transmits once per second cution time of the multiplexing times. Set the OV. 4 43k instead of twenty If you have a 1MHz clock but routine (which runs 601 times 5 timer enables so that all the 56k still no 601Hz at point 16, the per second); so the digits are 6 68k channels are toggled at 1Hz, likely culprit is the power - stored in seven -segment form, 7 75k then use the output on/off keys most to put the channel under test in up reset circuit (C1, D1, R8 and ready to be written to the the opposite state to that of the Tr1). Try momentarily shorting display leds. 52 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com assembly -language listing of the instruction is always DD, and to room Interrupt structure around make for software. However, such a the third byte is the displace- additional functions, remember Although there are only two listing would only be of more ment, which in this application that the seven -segment look -up sources of interrupts, namely use than the flowcharts to con- is the same as the lower half of table must remain on a 256 -byte the 20Hz and 601Hz c.t.c structors who intend to modify the ram address. For example, page boundary. Also, beware of channels, the priority between the program, and such people at eprom address 216 is the relative jumps which go past them had to be carefully defined are likely to have sufficient machine code DD 7E BB, which your added code. The safest, if to meet the following require- knowledge of Z80 assembler disassembles as LD A, (IX not the most elegant, way of ments: and machine code to dis- + BB). This loads the accumu- adding code into the middle of a To maintain a regular rate of assemble small blocks of code. lator from ram address 8OBB, routine is to insert a Call instruc- multiplexing the display, which To assist in this, each block in whose function can be looked up tion inplace of the last three is essential to avoid visible the flowcharts has alongside it in Table 3. bytes (or more if necessary to flicker, the 601Hz channel must the eprom address of the first Testing for a keyboard row or make up a complete instruction) be allowed to interrupt any instruction corresponding to the for a particular key is done with before the place where you want routine currently in progress - process written inside the block. bit test instructions, which are to put the added code. The Call including its own keyboard The following paragraphs recognisable by the fact that the is to an address above the end of service routines, which in some should also help. first byte is always CB. The the existing program, and at cases can take tens of milli- Most accesses to the scratch - meanings of the individual bits that address should be the seconds to run. pad area of ram are made using in registers C, D and E are given instructions replaced by the To maintain accurate time- indexed addressing via the IX in Table 4. Call, followed by your additional keeping, the 20Hz channel must register; the first byte of the If the existing code is moved code. be allowed to interrupt key- Table ram allocations board services; fortunately it 3. Scratchpad and setting storage format need not interrupt the display 8080 Password to distinguish Variations multiplexing /keyboard 8081 Reset from power -up A number of simple modifica- scanning routine, which only 8082 Interrupt vector for tions may be made, either to takes about 330µs. 8083 601 hz CTC channel reduce the cost of the system or When the clock minute incre- 8084 Interrupt vector for to change its operation in some ments, the 20Hz interrupt 8085 20Hz CTC channel way. For example, if all the service routine (i.s.r.) has to 8086 Interrupt vector for appliances to be controlled are search for, examine, and possi- 8087 spare CTC channel in the same room as the control bly act upon, all the active timer unit, a substantial cost saving 8088 Counter 2 (5 to 1 Hz divider) settings; a process which can 8089 Counter 1 (20 to 5Hz divider may be achieved by dispensing take more than the 50 ms 808A Enable 1/2 with the f.s.k. remote control. interval between interrupts. 1 808B Not used Instead of IC13 on the processor The 20Hz channel must there- FLASHER 808C Pointer 1 board, the circuit opposite pro- fore be able to interrupt its own CONTROL 808D Pointer 2 vides a directly- connected service routine. 808E Temp. store 1 signal to operate each opto- 808F Temp. store 2 The 601Hz i.s.r. cannot be coupled switch. It would even allowed to enter a keyboard 8090 Search store be possible to mount some or all service routine if it has inter- 8091 Not used of the switches inside the rupted a 20Hz i.s.r because the 8092 Day (bits 6 to 0) control unit, to save on boxes, 20Hz routine will be using the 8093 Tens -of -hours and to connect the appliance c.p.u. registers. (The original 8094 Units -of -hours NORMAL 8095 Tens -of- minutes contents, needed for keyboard (CLOCK) 8096 Units -of- minutes The 601 Hz ISR compares the servicing, are saved on the stack DISPLAY 8097 Not used at the start of the 20Hz routine contents of 809C and 8OBC to 8098 Tens -of- seconds determine whether any out -put and replaced at the end). 8099 Units -of- seconds change is required. If they are The first three of these 809A Not used different, the contents of 809C requirements are easily met by 809B Timer enables are transmitted and copied into clearing the c.t.c. channel's 809C Output status 80BC. interrupt flag and enabling 809D Repeat transmission password further interrupts, (using the EI 809E to 80AC Not used and RETI instructions), before 80AD Today (bits 6 to 0) entering a potentially time - REAL 80AE Hours Storage Format consuming routine. The 20Hz TIME 80AF Minutes b -c -d i.s.r. takes care of the fourth CLOCK 8080 Seconds Bit 716151413 2 1 0 requirement by manipulating 80B1 Active /suspended /cancelled P +0 0 0 0 0 0 0 SA the Key Enable status in ram 8082 Repeat (bit 7) and days 4- P +1 0 S1S1M TIW T F location 80BE. This location is 8083 Tens -of -hours P +2 0 LAST DAY set to FF (key services disabled) 80B5 Units -of -hours On Time P +3 0 0 1 HOURS ON (BDC) before the 20Hz i.s.r. enables 8085 Tens-of-minutes (7 -seg) interrupts, and the original con- SETTING ß0B6 Units -of- minutes J 4 P +4 0 1 MINUTES ON (BCD) tents and reinstated at the end of DISPLAY 8067 Tens -of -hours P+ 5 0 0 HOURS OFF (BCD) 8068 Units -of -hours Off Time the 20Hz i.s.r. along with the P +6 0 'MINUTES OFF 8089 Tens -of- minutes (7 -seg) 4 (BCD) processor register contents. ß06A Units -of- minutes P +7 CHANNELS 8OBB Channels 8OBC Output status 4 Flowchart 80BD Not used Ram address, where P is any multiple of 8 from 80E0 to 83F8. Space does not permit publi- 808E 00: keys enabled, FF: disabled) cation of a fully commented 80BF Keyboard debounce counter ELECTRONICS & WIRELESS WORLD MAY 1986 53

www.americanradiohistory.com REMOTE TIMER

Table 4. Flags Register D Bit Pressed Key Register C 7 Set clock Repeat Channel 7 Bit Meaning of Flag (when at logic 11 6 Last step Saturday Channel 6 7 Seconds count is enabled 5 Next setting Sunday Channel 5 6 Minutes count is enabled 5 The CHECK subroutine is enabled 4 Down Monday Channel 4 4 Non -control keys are enabled 3 Jp Tuesday Channel 3 3 Settings for a particular CHANNEL are being examined /altered 2 Next step Wednesday Channel 2 2 Settings on a particular DAY are being examined /altered

1 REATed settings are being examined /altered 1 Normal Thursday Channel l 0 A NEW setting is being entered 0 New setting Friday Channel 0 mains leads to the control unit, Flowchart Register E either with standard mains Copies of the flowchart annotated plugs and sockets, or via with eprom addresses and too Bit Key Row "chocolate- block" connectors extensive to print here are available 7 Control or barrier strips. But remember from the editorial office in return for 6 Days & repeat that the total current for all the a stamped and addressed envelope 5 Timer enable /disable 4 Output on /off is then supplied from marked 'Remote timer'. Included is appliances 3 -0 Not used a single wall socket, and must the hexadecimal listing, some notes therefore be limited to 13 amps. on battery backup, components lists and p.c.b. hints.

when the seconds change from causes the on -time to be copied stored, the display shows Operation 59 to 00. The minute count is into the off -time. In most cases 'none'. To set the clock when power is re- enabled on returning to this means that some of the 3. Use the 'up' and 'own' keys to first applied (the day leds should normal mode, which is done by off -time digits can be skipped, rotate the be flashing): pressing 'next step' while the or only need to be incremented active /suspended /cancelled 1. Set the day by pressing the units -of-minutes digit is by one or two. At this stage status if required. 'Next step' appropriate key. flashing. the tens -of- hours -off digit is may be used to step through 2. Press 'next step'. This makes To enter a new timer setting: flashing; the off -time is the rest of the setting; the tens -of -hours digit flash; 1. Press 'new setting'. If the corrected to the exact time whichever part is flashing may use the up and down keys to display shows 'full', there are required in the same way as be altered. ('Next step' is change it if required. already a hundred settings the on -time. ignored if the cancelled led is 3. Use the next step up and down stored, and one must be 5. With the units -of-minutes -off on, as there is no point in keys to step through and cancelled to make room for the flashing, pressing 'next step' altering a setting if you're change the other three clock new one (see below). Normally, causes the channel leds (which going to cancel it). digits in the same way. 'Last the active led flashes, and the double as timer enable leds in 4a. At any stage in the above, step' can be used to correct a on -time is set to 00:00. At this the normal clock display) to 'next setting' may be used to previous digit if a mistake is stage the up key may be used flash. Any combination of display the next appropriate made. to change active to suspended channels may be selected, setting (if there is another one). 4. With the right -hand digit if required. though in practice it is unusual If the previously displayed flashing, press 'next step' or 2. Press 'next step', which makes to select more than one. setting was left with no 'normal' on a time signal. The the repeat led and all the day 6. Press 'normal' or 'next step' to channels selected or with the seconds start counting from leds flash. Any combination of return to the clock display. cancelled led on, it is deleted zero at this point. days may be selected; the last 7. If 'normal' is pressed at any from the setting ram. If there To correct the clock time: one you select is stored as the stage when no channels are are no further stored settings 1. Press 'set clock', which makes last day, and its led flashes to selected, the setting is appropriate to the group the seconds digits flash. remind you which one it is. If cancelled and the display goes selected at '2' above, the 2a. If the clock is less than half a the last day is deselected, the blank except for the cancelled display shows 'none' with a minute fast or slow, press nearest selected day to the left led, the colon and any output day, repeat or channel led lit to 'normal' on a time signal. This becomes last day instead. leds which were already on. remind you which settings you sets the clock seconds to zero, If repeat is selected, the Press 'normal' again to return were examining. If you were and if the clock was slow, (i.e. repeat led flashes. By to the clock display, or press looking at all stored settings, if the displayed seconds were definition, there is no last day 'new setting' to start again. all the channel leds are lit. 30 or more), the clock time is stored in the setting ram, but To examine and alter stored 4b. Pressing 'normal' at any stage incremented by one minute. the last selected day is still settings: restores the clock display, 2b.If the clock is out by more than held in a register, and becomes 1. Press 'next setting'. The unless the last setting to be half a minute, press 'next step' last day if repeat is deselected. repeat led and all the channel displayed was left with no repeatedly to step through If there is only one day and day leds flash. channels selected or with the days, hours and minuts, using selected, it cannot be 2. To examine all settings for a cancelled led on. In those the day keys or the up and deselected because a setting particular day or channel, or all cases, the setting is deleted down keys to correct with no days would be repeated settings, press the from the setting ram, and the whichever part of the display is pointless; another day must be corresponding key; to examine display is blanked except for flashing. The seconds count is selected first. 'Next step' will all stored settings regardless of the chancelled led, the colon not affected unless the units -of- also be ignored until at least content, press 'next setting' and any output leds which minutes digit is altered; in one day has been selected. again. The first appropriate were already on. Press which case the seconds are set 3. Press 'next step' four more setting (if there is one) is 'normal' again to restore the to zero and will resume times to step through the four displayed with active or clock display; or press 'next counting when 'next step' is digits of the on -time, using the suspended flashing. If the setting' to return to step '2' pressed again. If the tens -of- up and down keys to change setting is not a repeated one, above; or press 'new setting' to minutes digit is altered, the each one while it is flashing. the last day also flashes. If set up a new setting from minute will not increment 4. Pressing 'next step' again there are no such settings scratch.

54 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com by M. E. Theaker, B.Sc.,

Measuring M.I.E.R.E. A simple and accurate method of ensuring the correct tape speed

It is often important to en- one end, unscrew the cassette do note the exact number of fessional recorders is ± 0.5% sure that the speed of a and measure the diameter of revolutions n1 at which you and for domestic recorders cassette recorder is the empty hub (h) and the start to time. After timing for a ±2 %. reasonably close to its correct diameter of the full spool (f) us- duration d seconds (the longer Method 2. If the counter is speed, either to ensure the cor- ing the vernier calipers. The the better) note the number of driven from the feed spool in- rect pitch of music or the cor- total thickness of the tape on revolutions n2. If you are using stead of the take -up spool then rect frequency of relayed data. the full spool is (f -h) /2, and if the recorder's counter don't the same basic timings are One method of doing this is to the number of revolutions is forget the conversion factor k. made, but the equations used use a standard -frequency tape nT, then the thickness of the The tape speed is, are and measure the output of the tape, t = (f -h) /2nT. Tape speed cassette recorder on a fre- It is wise to do all of your s = 7r (n2-n1) s = 7r (n2-n1) quency meter. Having neither calculations in one set of units, [h+(2nT+2n2nl)t] at my disposal, I devised a preferably millimetres, so if [h + (2nT + 2 n2 n1) t] method which only requires a your calipers measure in inches d mm/s watch, a pair of vernier calipers don't forget to convert the d and a cassette. Basically, the measurements to millimetres and, since the correct speed of Error method consists of measuring first. Tape thicknesses are, cassette recorders is 47.625 (s-47.625)%a the thickness of the tape and typically, 18 µm (0.018mm) for mm /s (1¡ i.p.s.) the speed error then measuring the time for a C90 cassettes and 12µm is 0.47625 given number of revolutions of (0.012mm) for C90s. the cassette when playing the e = (s- 47.625)% recorder or The player. Making a speed test tape cassette used should preferably Tape speed 0.47625 be a C60 (although a C90 will If the counter on the recorder is These calculations can easily Having determined the speed do), it must be of screwed con- coupled to the feed hub instead be carried out with the aid of a of a recorder, it is now possible, struction and the tape hubs of the take -up hub then see scientific calculator, but for with the aid of an audio signal should be clearly visible. (The Method 2 (later). Having re- those who need to carry out the generator and a frequency latest range of Sony cassettes assembled the cassette, rewind calculation many times (for ex- meter, to make a standard are particularly good for the it to the start. Either by direct ample, when adjusting the speed tape. Using the fre- purpose as the tape clamp pro- counting or using the recorder's speed of a recorder or player) a quency meter, set the signal vides a very easy reference counter, count the number of short computer program is in- generator frequency to when counting the hub revolutions of the hub for, say, cluded at the end of this article. lkHz x (100 +e) /100 and then revolutions.) 5 minutes (using a watch or Although written for the Spec- record several minutes of this stop watch). Do not time the trum, it can easily be adapted signal. When replayed on any first few revolutions, since this for any other computer. The machine the speed error will be Measuring tape thickness will lead to starting errors, but tolerance permissible for pro- indicated on a frequency meter, the tens of Hertz indicating If your cassette recorder 10 REM Tape speed program units of percentage error and doesn't have a counter, this will 20 INPUT "Counter factor (revs /count) ? "; k units of Hertz indicating tenths 25 INPUT "Counter be the most laborious part of on take -up, yin ? "; a$ of one percent error. For max- 30 INPUT "Full spool diameter (mm) ? "; f the process. Run the cassette imum stability of the test tape a from start to finish and count 40 INPUT "Input hub diameter (mm) ? "; h 50 INPUT "Total revolutions ? "; nT C60 (or shorter) cassette must the total number of revolutions 60 LET t = (f- h)I(2`nT) be used. of the take -up hub. Most 70 LET L = PI `nT`(h + (nT 1)`t) /1000 cassette recorders, however, 80 PRINT "Tape thickness +'; t; "mm" have a counter driven from the 90 PRINT "Tape length = "; L; "metres" take -up hub, and this makes the 100 INPUT "Start count?"; cl Derivation of the formula process much easier. 110 LET n1 = k`cl The length of tape on the first 120 INPUT "End First, the ratio of the hub count ? "; c2 revolution of the hub is rh, 130 LET n2 = k`c2 revolutions to the counter is where h is the diameter of the 140 INPUT "Time (sec) ? "; d found by noting the change in 150 IF d =0 THEN GOTO 20 hub. The length of the second counter reading for, say 20 170 IF a$ = "n" THEN GOTO 200 revolution is greater since its revolutions of the take -up hub 180 LET s = Pl* (n2 n1) `(h + (n2 + n1 1)`t) /d diameter is larger by twice the and then dividing the change of 190 GOTO 210 thickness of the tape (t). Its reading into 20 -k = n /c. Now 200 LET s = PI`(n2 n1)`(h +((2`nT) +2 n1 n2)`t) /d length is a (h + 4t) and so the play the cassette from one end 210 LET e = (s 47.625)/0.47625 length of the nth revolution is to the other and note the 220 PRINT "Tape speed = "; s; "mm /s" a [h + 2(n -1)t] change in the counter reading. 230 PRINT "Error = "; e; "percent" The total length of the first n The number of revolutions of 240 GOTO 100 If the hub revolutions revolutions of tape is equal to tape (including the leaders) is k are counted directly, then enter 1 for the counter factor. To change the cassette and recorder the sum (addition of the lengths times the change in counter conditions enter 0 for "Time" and this will take you back to the start of each revolution. This sum is reading. of the program. an arithmetic series whose first With the cassette wound to term is it and whose common ELECTRONICS & WIRELESS WORLD MAY 1986 55

www.americanradiohistory.com TAPE SPEED

ir(n2 revolutions for the entire side of difference is 27rt. The total _ - ni) Accuracy length of tape for n turns is a C60 cassette (30 mins) is tim- [h +(n2 +n1 -1)t] L = r.n(h + (n - 1)t) The accuracy in measuring the ed with an accuracy of 0.5s, Using this equation and the speed error (and the speed) is then an error of 0.03% will be Similarily, if the revolutions of dependent upon the accuracy introduced, which brings the information found when the feed spool are counted, then of the with which the various total error of 0.1% If, however, measuring the thickness the length of tape is tape, you can calculate the total measurements have been the revolutions for the first 5 made. If the difference between minutes are timed to an ac- length of the tape in the L = an[h + (2nT + 1- n)T] cassette by making n equal to the full -spool diameter and the curacy of 0.5s, then the hub diameter is measured to resulting error is 0.15 %, bring- the total number of revolutions where nT is the total number of within 0.1mm then the ap- ing the total error to 0.22 %. It of the cassette (nt) The nominal turns on the cassette. The parent speed error will be is important, therefore, to carry length for a C60 cassette is 90m length of tape between revolu- 0.05% An error of 1 in deter- out the time measurement over and for a C90 is 135m, plus a tions n1 and n2 in this case is leader of about 0.5m at each mining the total number of as long a period as possible to bet- revolutions will introduce an er- achieve the highest possible end. The length of tape 71-n2[h + (2nt + 1- n2)t] - ween n1 and n2 revolutions is ror of 0.02% The most critical accuracy. 7rn1[h +(2nt +1 -nI)t] is the measurement of the dura- L2 - L1 = rn2[h + (n2- 1)t]- = ir(n2 - ni) x tion of the revolutions from n1 7rni[h+(ni - 1)tl- [h + (2nt + 2 -n1- n2)t] to n2. If the number of the by T. Loughlin B.Sc. (Hons.) 10bit digital recorder Using modern data conversion i.cs, very -low- frequency analogue signals can be recorded on tape with high accuracy.

My circuit for recording tape recorder wow and flutter can be reduced by filtering the sample as shown in Fig. 2a. As low- frequency ana- on the recorded signal. Good output since the frequency of can be seen from the diagram logue signals on ordin- quality domestic audio recor- the error noise is equal to the the uart is configured for a 6bit ary audio quality tape ders have a frequency range of sample rate (approximately). character length, one stop bit recorders1 has been used in approximately 50Hz- 10kHz. To The a -to -d converter used and even parity. Five character medical establishments record signals from d.c.- 100Hz, here is the Ferranti ZN432E bits, TBR1.5, are used for either including the Royal Victoria say, some form of modulation is which is reasonably priced. the five most significant or five Hospital and City Hospital in required to shift the base -band Input bias and offset resistors least significant bits of the Belfast East Dulwich Hospital. frequency into the recorder R1.6 are chosen to give a 0 to sample word; character bit 6, Response from users has audio band. +2.5V input voltage range at TBR6, known as `Byte', is used to suggested that increased Analogue techniques such as R5, Fig. 1. For other ranges indicate most or least resolution giving greater frequency and pulse -width refer to the data sheets'. significant. dynamic range would be modulation may be used but Op -amp ICisa provides At power -up time, reset cir- desirable. This is particularly so these techniques suffer from the shifting and scaling for input cuit IC2a, Fig.1, resets the uart. when recording electro- inherent disadvantage that tape signals while IClsb provides When IC2a pin 3 goes low again cardiograms where common - wow and flutter causes a direct some anti -alias filtering. The the transmit -register -empty mode potentials can cause the modulation of the carrier signal. ZN432E draws typically 35mA (TRE) flag, IC1 pin 24, goes high e.c.g. to 'wander' - an effect Upon replay and demodulation, so battery operation is not as after 18 clock cycles on the known as base -line drift. noise thus induced has a practical as with the 8bit circuit clock falling edge (Fig.2c). The circuit described here frequency range within the base using a c -mos 8703 converter. Transmitter-buffer-register- uses ten -bit conversion devicies band so it cannot be filtered out. The 10bit a -to -d converter load (TBRL), connected to TRE, while retaining the same basic One technique used is to requires a start -conversion then initiates transmission of recording technique as the 8bit record a reference d.c.' channel signal closely synchronized to the first character which will be recorder. This gives four times which upon demodulation is the clock driving its internal invalid. On the next clock rising the resolution as before at the summed in antiphase with the successive -approximation edge, data in the transmit expense of sampling rate, which signal channel thus reducing the register (sar). Precise timing register transfers to the is reduced by around half, noise component of the signal. generation will be described transmit buffer causing TRE to assuming the same data rate. In the digital system however later but the clock used is the 16 go low. At 4800 baud, a rate which the effect of wow and flutter is times baud rate clock derived Now assuming that `Byte', most reasonable recorders eliminated since timing is estab- from IC7a through dividers IC3b IC3 pin 1, is high then TRE is should handle, the sample rate is lished by a crystal controlled and IC11. The data is then gated to start conversion on the 267Hz, making the unit suitable replay circuit which updates the multiplexed into the uart ICI ZN432E. This pulse will be for many data logging appli- analogue output at fixed inter- transmitter -buffer register closely aligned with a clock low cations and certainly sufficient vals. Distortion is then a through selector IC5 and gates pulse thus meeting the timing for most medical applications. function mainly of quantizing ICsa, b, wired as a selector gate. criteria for this device. The A digital recording technique noise and bit drop -out error. Data is placed on the tape as falling edge of TRE toggles the is used to reduce the effect ofd The quantizing/stepping effect two nine -bit sequences per 10bit `Byte' bistable device. 56 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com + 5V -5V +5V digital analogue analogue I 'T TD 13 R1

Ground ° j Ground 4 Ref amp. 1 2 1r4 26 TER Bit 10 14 Vcc" analogue digital A 5k gr t.sb. 19 18 CRL, 34 36 s2 48V CLS1 Vref 20 5 7 27 2A Y -i ERE 5 Retomp Analogue R9 3 21 9 28 74057 input Iref 22 12 PI 5k 3A 3Y 220k R R10 S85 10k 4 11 23 38 8 CLS2 47k IC16a 2.1 Gain R5 24 44 4Y TBR4 3 RRD 47_11_4 16 out 25 SFD TL0B2 1k25 IC4 RS SEL 26 GRO 10k'11 ZN432 1 115

220k 27 C1 J Shift R2 12 Comp.gnd. Bit 1 A m.sb. 6042 f - 1k25 a 2 Thot* I1313 C2T11 / 11 IC6 30 NT 25 1 8 4011 ° °

1 5 . C4 1 I 5 12 CK SC 4013 100n 10} I J8 17 28 i7 A 12? 10k 31 »6 Digital 76.8 kHz 23 output (410 14800 TBRL O baud) /z4520 to mic 2 11 5 I 24 TRE 3 socket 4 ICBa 6 B 1 D Q 100 12 5.Byte 112 L2 IC3b 1E11 EN1 8 3 4520 13 1130 Q C K1 1 14 14 114d 3 21R 1 10 8 Tx CK RxCK I 10k 384kHz 40 17 9 ,15 (2400 16f u.a.rt clock C9 100n "2a baud)

Fig. 1. Record section. Analogue signals are converted into a 10bit digital word and fed to the uart in sections.

Fig. 2. Record timing. In this system, a logical one is encoded as a rising edge and a logical zero as a falling edge.

Complete 10 bit sample I typical ) b208»5 Sample rate = 267 Hz (a) Low byte High byte 1s b. D-bit I D-bit I 0-bit D-bit Byte D-bit D-bit D-bit D-bit m sb. Byte D-bit = dota bit Start D-bit Parity Stop Parity Stop Start I I 9 I 8 I 7 6 =0 I 5 4 I 3 2 Bit1 =1 10 Transmit data ICI pin 25

Bit clock IC8 pin 6

IC9 pini

Digital output IC7 pin 10

THE ICI pin 24

Byte IC3 pin 1

H13ys

Transmit clock ICI pin 40

THE 1C1 pin 24

TBRL ICI pin 23

Byte IC3 pin 1

f START CONVERS. IC4 pin 28 Conversion time = 143ps Status IC4 pin 14 Data 0 9 iÏCtR 1A(d3tt ! j Valid t _ Start sending Start sending low- byte high -byte (b) (cl

ELECTRONICS & WIRELESS WORLD MAY 1986 57

www.americanradiohistory.com DIGITAL RECORDER

A problem may arise here. at this stage gating the lower driven. The biphase decoding circuit START CONVERTION going low five bits of the sample into the Serial output data from the comprises IC7b, IC8b, IC2d, and initializes the ZN432E sar so uart. Signal TBRL loads the uart, IC1 pin 25, is encoded into IC7b. Clipping circuit IC7b data present at uart inputs transmitter -buffer register and a biphase form by IC9a, IC8a and produces a narrow pulse for TBR1_5 will change. The maxi- the TRE (TBRL) rising edge trans- IC7c (Fig. 1) as shown in Fig. 2a. each transition of the encoded mum hold time requirement for fers this data into the transmit In this system a one data bit is digital signal. Counter IC8b, the uart is 9Ons so the delay register and starts transmitting encoded as a rising edge and a driven by the 16 x uart clock, from TBRL high through IC2b IC4 it. 'Byte' low output inhibits the zero as a falling edge of the counts to 12 or greater unless and IC5 must be greater than start-conversion pulse and is digital output to the recorders. reset by clipper output pulses. If this. also transmitted as bit six. Output level is around 50mV. the counter goes to 12 or greater. However since typical propa- The falling edge of TRE Inspection of the output ICZd output goes low then high gation delay of IC5 is 16Ons and toggles the 'Byte' bistable waveform shows that the causing bistable device IC9b to the typical uart data hold time is device high, Fig. 2b, and the five highest frequency present is toggle. 4Ons, problems should not most -significant data bits are equal to the baud rate used e.g. Output of IC9b as can be seen normally arise. If this does loaded into the uart by TBRL at 4800 baud the maximum is from the timing waveforms is cause a problem then delay the being low with bit 6 high. When 4800Hz. decoded serial data. It is start -conversion pulse from the uart i.c. has finished High level replay signal from however possible that bistable TRE. transmitting the lower five data the recorder would normally device IC9b may be in the wrong The converter takes 11 clock bits and associated bits, TRE suffer from a phase distortion state initially in which case the cycles or 143µs at 4800 baud to again goes high on a clock caused by the recording process decoded data will be inverted. make a conversion. When the falling edge. The five most - itself.' and appears usually as This produces a parity error uart has finished transmitting significant data bits and 'Byte' shown in Fig.4a. and /or a frame error signal from the first character TRE goes high are loaded into the transmit This signal is applied to a the uart which cause bistable (Fig. 2c). Output of 'Byte' is low register ready for transmission. phase -equalizing circuit device IC17b to toggle. Output Q Being high, 'Byte' output comprising IC19a and associated of this bistable device drives Fig. 3. Replay section. gates a start- conversion pulse to components (Fig.3) to exclusive -or gate IC7d pin 13 High -level replay signal the a -to -d converter, Fig. 2c, compensate for this distortion. which gates decoder output to would normally suffer which begins taking a new It is then amplified, IClsb and the uart serial input; the net' from phase distortion but sample while the upper five bits squared, IC2c, to obtain a effect is to invert the data here it is applied to a are transmitted. The sequence t.t.1. -level signal that is close to stream seen by the uart. The phase -equalizing circuit. thus repeats itself and is self' the original recorded signal. circuit then rapidly synch-

1-5V digital I órouiiu +5V analogue I -5V analogue TSVdigital nalogue nIdigital

Gnd.digital

Gnd. digital

.5V analogue O 47:T 100n Gnd. analogue O I1 47y 100n Y y 12 3 1DCLR Byte Vcc -5V analogue 0 j` RBRi T 11 4 5 18, rc12 10 6 7 19 R22 74074 9 11 10 20 -V< 245V 8k2 8 13 12 21 R21 IC 50 [í Thn 6 2 8 IC 6 19 _2c C13 1N4148 CI 8 10 R 8k2 7 R9 7 C,10 20 1E* TL082 5 Digital 3 100n + 4 22p input 8k2 R25 412

IC1 R1 470k R26 10n R23 R24 3 3 100k 6402 IC18 470k 47k 10k 6 1 10 TL 081 A D 12 IC14c 11 IC13b

13 12 14 13 4023 R27 D p FE 5 z 13B 3 9 8 3 4 15 11 12 27k IC9b 11 IC7d 1341 1 i 14 12 PE IC6c 6 6 2 C13c IC7h R 33k 100n IC13a 15 100p C2d 40106 5"""'"'D C4Z, 19 n R1

9 13 iC17a R17 D Q C12 C10a 6k8 4013 4k7 T100n33k IC17b l6t u.a.rt clock 11 12 ..... 6 4 ICI Pin40 ORR //Signal present' R18 220 6 . 10k Analogue output 8C109 IC10b D

58 ELECTRONICS& WIRELESS WORLD MAY 1986

www.americanradiohistory.com Digital input OV -

Phase equalized IC19Pin 7 input 208ps It-1 f 104ps Encoded input IC2 Pin 10

4 Clipper output IC17Pin I 1 1 1 1 1 1 1 I I 1 1 l 1 I l 1 I I I 1 I I I I 1 1 l l

Count 12 -15 IC2 Pin 11 fIt -156ys Received data IC1 Pin 20

I I I I I I I I I I 1 1 I I I Start Bit 10 Bit 9 I Bit 8 Bit 7 Bit 6 Byte Parity Stop I Start Bit 5 Bit 4 Bit 3 I Bit 2 I Bitt Byte Parity Stop

(al

Data received IC1 Pin 15

Data received ICI Pin 18 reset Latch lo'Byte. IC12 Pin 9 li-Inhibited by PE & FE Latch d -to -a ICe Pin 3,5 Inhibited by PE & FE _I0 cony. Analogue output IC18Pin6 ( -Ve Timing detail I- Receive clock IC1 Pin 17 Parity error ICI Pin 13 Dato received IC1 Pin 19 Error FF IC1 Pin 13 Data received IC1 Pin 18 reset Data received IC7 Pin 11

'Byte' 1 RBR6 ) IC1 Pin? t-1 Data stream inverted Latch low'Byte "1C1?Pin 9 Phase inversion timing Latch d -to -a IC15 Pin 3,5 coñv. lb) (c) (dl

ronises itself to incoming data, converter so ensuring good can be improved by using a Fig. 4. Replay timing. Fig. 4d. tracking between the two sample-and -hold circuit such as Synchronization of the Assuming then that a correct devices. However the output, the LF398, which may be circuit with incoming data stream of data is being received IC18 pin 6, will be inverted so connected as shown in Fig. 5. occurs rapidly. the problem is to reconstruct the after filtering (ICioa) to remove The circuit as shown without a 10bit analogue samples. When a quantizing noise it is inverted s/h device will have a dynamic full character has been received, (IClob). If no signal is being sample error of 2% on a 50Hz data-received flag DR, ICI pin received or the replayed data is full scale sinewave inputs. 19, goes high in the middle of incorrect for some reason then the stop bit on the clock rising parity or frame -error signals Thomas Loughlin graduated edge, Fig. 4c. inhibit output -latch pulses and from Queen's University Data -received bistable device cause the `signal present' lamp Belfast with a B.S.c. (lions) IC17a is driven by the inverted to go out. Electrical and Electronic clock so the next clock falling The circuit described here Engineering in 1979. Now he is References a Senior Medical Physics edge transfers DR to its outputs. was built and tested to 1 Loughlin T., Analogue recording using Technician at the Regional digital technique, Wireless World, Feb. Signal Q of IC7a is used to reset validity of the determine the Medical Cardiology Centre in 1983 pp 74/75. DR via Wit to prepare for the design concept and has been Belfast developing equipment 2 Ferranti Semiconductors, ZN432E 10 next character and the next used to good effect for recording for use in cardiology, including Bit Successive Approximation clock falling edge transfers DR e.c.g. signals. Certain features computer hardware and Monolithic A/D Convertor Data Sheet, low to ICf7a output which is thus which contribute to the absolute software. Prior to that he 1982. a pulse one clock period wide. overall accuracy of the system worked as an analogue and 3 Koanantakool, T., 4800 Baud Cassette If the received character are not included such as digital designer and as a Interface, New Electronics, Vol 12, No 21, contained the lower five bits of converter offset and gain systems engineer on computer October 30 1979, p. 36. control systems. Thomas' the sample then bit 6, ICI pin 7, adjustment potentiometers. 4 Smith, P. Zorkoczy, P. I., Data current involves Recording on Audio Cassette, Wireless is low so bistable- device output Note however use of project the displaying physiological World, February 1982, pp 50-52, 62. is gated via IC13b to register IC12 separate analogue and digital 1 signals using very high which stores the data. power supplies and grounds. 5 Clayton, G. B., Data Convertors, resolution graphics. Macmillan Press, London. 1982, pp The next received character Dynamic sampling accuracy 45 -46. will contain the five higher bits of data and bit 6 will be high so - SV analogue the data received pulse is gated +5V analogue vja JCi3a to the output d -to -a converter, IC15, Fig. 4b. The five lower bits from IC12 and the filter five From To input R5 upper bits from the uart are ICl6b Pin 7 on ZN432E thus clocked into the DAC1000 output register and the analogue Hold capacitor Fig. 5. Dynamic sampling output attains the latest value. 100n can be improved ZN432E status accuracy The output d -to -a converter output IC4 Pin 14 by including a sample -and- obtains its reference voltage hold amplifier such as this from the ZN432E a -to -d one. ELECTRONICS & WIRELESS WORLD MAY 1986 59

www.americanradiohistory.com THE ALL -ELECTRONICS/ECIF SHOW

At Olympia, in Hammersmith, London, the British Electronics Week has come round again. Occupying even more space, with a greater number of exhibitors, the show has become a Alternative major event in the electrical /electronic calendar. From the 29th April to the first of May, Olympia will be full to overflowing with exhibitors. to tantalum The week actually consists of four exhibitions; The All- Electronics /ECIF Show, Circuit Subminiature electrolytic Technology, Electronic Product Design, and Fibre Optics. A fifth section has been capacitors with radial leads announced for inclusion in the Week in 1987; Power Sources and Supplies. We had are suggested as a low -cost planned to provide a map of the stands and a list of exhbitors, but this would have taken alternative to tantalum beads. up too much of our space; it is better left to the catalogue, available at the Show; instead The Waycom WSQ series has a capacitance range of 0.1 to we have concentrated on presenting some recent announcements of new products by 100µF with rated voltages exhbitors. Some companies are very chary of releasing details of products to be launched from 6.3 to 63V. The at the Show; so we will report on such releases after the event. aluminium capacitors are Your correspondents will have the unenviable task of attempting to visit every stand in this cased in aluminium with mammoth circus. For those unwilling or too busy to spend too much time there, we would welded internal connections. recommend that you get a catalogue and then find a spot to sit down and read the High -grade paper separators sections that interest you. This will save a lot of time. Also at the entrance to the Show for long -term reliablity. BA Electronics Ltd, Hitchin Road, there are stations that can provide computer print -outs of the positions of the stands that Arlesley, Beds SG15 6SG. have the products that may interest you. EWW 212 on reply card. Olympia has its own underground station, served during exhibitions by a shuttle train Stand No. 482. from Earls Court, which is the exhibition hall for the Fibre Optics section. Mains filter Compufilter has been designed to remove noise, r.f.i., and voltage transients from mains Function generator lines used with microcomputers and allied Among the products to be company are also showing d.c. peripherals. Each model displayed by Global power supplies, surface - comprises a series of filters Specialities is the Sovereign mounting breadboards using designed to eliminate both 8200 series of synthesized plastic leaded chip carriers, a incoming and outgoing 20MHz function generators. low -cost universal counter - interference by providing a Fully programmable through timer and a wide range of rack the GPIB interface, the systems and test -and- generators provide sine, measurement instruments. square and triangle waves and Global specialities corporation pulses with variable (UK) Ltd, Shire Hill Industrial SIL resistors amplitude, symmetry and Estate, Saffron Walden, Essex High volume production and offset over a 2mHz to 20MHZ CB11 3AQ. EWW 207 on improved manufacturing frequency range. The reply card. Stand no. 260. techniques have allowed Allen - Bradley to extend the range of its 700 series of cermet resitor networks in single in -line (SIL) high level of attenuation. A packages. The resistors are two -stage filter protects available in 4 to 14 -pin against incoming asymmetry packages with resistances and includes a transient from 2252 to 2.7M12. They are suppressor. Each socket is connected internally to a protected against asymmetry common bus (style A), as and is isolated from the individual resistors (style B) or others. There is a choice of as digital line terminators output socket types. Each (style E). All are fully tested. output is limited to 3A. Allen- Bradley Electronics, Cetronic Power Products Ltd, Ennia House, High Street, Hodeston Road, Stanstead Edenbridge, Kent TN8 5LY. Abbotts, Ware, Herts SG12 EWW 216 on reply card. 8EJ. EWW 209 on reply Stand No. 106. card. Stand no. 561. 6iì ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com tools for DATAMAN Lombard House, Cornwall Road, DORCHESTER, Dorset DTl 1 RX phone 0305 68066 telex 418442 micro engineering CIRCLE 31 FOR FURTHER DETAILS.' FAST EPRO PROGRAIV J Copies eight EPROMS at a pass all 25 and 27 series up to 27256 EPROM type is set by switches erasure is checked automatically control is simple -- two keys Alpha liquid crystal display checksum facility 6 hex digits FAST or NORMAL programming PLUS VERSION also hasi serial RS232 program & check CTS or DSR handshake ASCII, SIMPLE HEX, INTEL HEX t'f V`` MOTOROLA S or TEKHEX GANG- OF- EIGHT 1395 AFFOR BBL aT GANG-OF- EIGHT plus 445 Diagnoses bus troubles H'PRDV h R Helps mend micro boards Displays HEX on standard TV Z80 TJOR Z80, 6502, 6800, 8085 with text -editing facilities Designed for Schools Council All covered by one product inserts and deletes -to teach Z80 machine code Disassemblers included shifts and copies MENTA uses TV for display Plugs into micro socket bytes and blocks of code shows STACK & PROGRAM in HEX Hand -held probe identifies EMULATES EPROM in circuit ADDRESS, DATA and CONTROL using romulator lead supplied Editing facility includes lines at a touch. direct keyboard ASSEMBLER RS232- output DISASSEMBLER Prints a memory map Used to write & debug of an unknown system short machine -code routines showing ROM, RAM, I/O MENTA is a complete and EMPTY ADDRESSING SPACE controller with 24 bits of I/ C used for ROBOTICS TEACHER'S GUIDE, PUPIL READER Uploads and downloads MODULES (e.g. A to D; available using serial and parallel routines - RS232, Centronics Alb,' NT A . X99 PROGRAMS & EMULATES 2716 2732 2532 Useful for development particularly for piggy -back CoYPUIER BARGAINS single -chip micros -ring for our BEST OFFER Adaptor is available OLIVETTI M21, M24 to program 2764 & 27128 with 10MB hard disk if req. LOGS all tests and responses AUTO -CAD & M24 created this AD on PRINTER and ALPHA LCD "'Our expensive equipment Non -volatile memory stays on the shelf also EPSON PX8 retains test sequences for weeks - but SOFTY CHECKSUMS, RAMTESTS, is used every day- from READS /WRITES MEMORY & I/O - says big- budget customer EPROM ERASERS £ 39 Reports location of SHORTS on ADDRESS and DATA busses Prints out memory contents SOFTY.. £195 BUY IT R5', 9'R1' IT in ASCII, HEX or SOURCE CODE ADAPTOR... You cannot expect to mend £25 REFUND GUARANTEED microprocessor products with less postal expenses, if goods returned intact within 14 days a meter and a scope. PRODUCT IS USUALLY STOCK How many repairs would IN pay for your SuperDOG? TODAY DESPATCH IS POSS IBLE PHONE FOR A LITERATURE PACK VISA SuperDOC.. e395 VAT be added to prices www.americanradiohistory.commust SMALL SELECTION ONLY LISTED Etc £100 to 1150. MA250 - 1.BMC/S to 31.6 MC/S RING US FOR YOUR 1100. MA1350 for use with RA17 receiver £100. MA259G Precision frequency standard 5MC /S - REQUIREMENTS WHICH MAY BE 1MC/S - 100KHz £100 to £150. Panoramic Adaptor IN STOCK RA66 £150. RA137 and RA37 C40 to t75 LF convertor 10 to 9BOKC/S. RA218 Independent SSB unit £50 RA98 SSB -ISM Cavador £50. RA121 SSB -ISB convertor £75. STOP PRESS STOP PRESS STOP PRE EC964/7K Solid state - single channel - SBB - mains or battery - 1.8 to 27.5 MC/S and 400 to 535KHz £100 with manual Plessey PR1556 Solid State 60KC/S - 30MC/S 1400. Creed 75 Teleprinters - Fitted tape punch and gearbox for 50 and 75 beads - 110volr AC supply - In original transport tray sealed in polythene "obi - Ilk new 015FÁ. Redilon T711 Audio Teleprinter con- 'a vertor receiver solid state - supply 110 or 240AC - `. Made for use with above teleprinter enabling print -oat of messages recieved from audio input of communication receiver £15 with ctrull haled. Rediton TT10 Con- vertor as above but Includes transmit facilities £20. Oscilloscopes - stocks always changing Tektronix ! SE Laborato- Portable Battery or Meins Oscilloscope. WHAT'S NEXT 186 - 100MC/S £750. FM Recorder Sanghmd Sabre ries 111 Oscilloscope Solid State General pur- - - 111 14 channels £350. Trends! Matrix printers pose Bandwidth at 20MV /CM - - AF11 R- 5 level Baudot Code - up to 300 Bauds - for ose - DChannelt18/20MC/S print out on plain teleprinter paper £50 to £100. Trans - Rise time 19NS Calibrated Sweep Calibrator - - - telAH11R -As above but also 8 level ASCII (CCITT No Display 10CMSx8CMS Power AC 95 Volts to 100- - - 2 and CCITT No. 5) Like new £100. Army kid tele- 190 Volts to 260 or 24 Volt DC battery Size. - phone sets. Type F -L and J Large quantity in stock W.25.5.CM H25.5CCMS 56CMS Deep - - - - £6 to £15 depending on type and quantity P.O.R. Don WT11.4KGS- Carrying handle- Tested in faircondi- 10 Telephone Cable half mile canvas containers instructions £120.00. - tion with operating £20. Night viewing Infra -rod AFV padscopee - Twin Eyepiece - 24 volt dc supply £100ea. Original cost to government over £11,000ea. SINN Murton -12 or 24 volt input - 240 volt AC sinewave output - various wattages P.O.R. XY Ploten and pen recorders various - P.O.R. Ferrognph urea 7 Tape recorders mono £100. stereo £150. Signal Generators verleus - TF995/A3 £60. TFB01 D /Ss- 10MC /S to 485MC /S £90 TF144H /A4 £90. TF1060/2 £60. HPBOBA - £90 £140 Leetronexl HP808 £50 HP814A £100 HPo18B £100 HPB20A £100. Marconi TF108411/5 £100 TF791 Deviation meter £100 TFg93A Power meter £50 Aedal mut assembly 300 high complete with 16ft whip aerial to mount on top - lfi n' guyropes- insulators - Base and Spikes etc., in heavy 1-31 -3 JULY 19867986 duty carrying bag - new £30. Racal frequency counter Type 836 £50 Tektronix plugs -Ins -1 Al £50,1 A2 £40, Latest Bulk Government Release - Couor Oscillo- 1A4 £100 M£50. All items are bought direct from H.M. 1 scope CDU150 (C7531/3) £150 only. Solid state general Government being surplus equipment: Price is Ex I Phone for purpose bandwidth DC to 35MHz al 5MV /CM - Dual works. S.A.E. for enquiries. appointment Channel - High Tart htneu display (8,10cm) Full for demonstration of any items. Also availability or delayed time bate with gated mode - Risellme IONS price change. V.A.T. and carriage extra. - Illuminated graticule - Beam finder - Calibrator LEEDS ELECTRONICS 1KHz squarewave - Power 100 - 1209.200V - 250 EXPORT TRADE AND QUANTITY volts AC - Size W 26CM - 41 CM deep - WT 12.5 K.G. carrying handle - colour blue - protection cover Iront DISCOUNTS GIVEN containing polarized viewer and camera adaptor plate JOHNS RADIO (0274) 684007 - probe (1) - Mains lead. Tested In Fair condition with WHITEHALL WORKS, operating Instructions EXHIBITION - £150.00. 84 WHITEHALL ROAD, Communication Recievers. Racal 500KC/S to 30MC/S EAST BIRKENSHAW, BRADFORD In 30 bands 1MC/SWIDE - RA17 MK11 £125. RA17L BD11 2ER £150. RA117E £200. New Metal Louvred Cases for above £25. All receivers are air tested and calibrated In our workshop - supplied with dual cover - operation WANTED: REDUNDANT TEST EQUIPMENT - Instructions - circuit - in lair used condition. Racal RECEIVING AND TRANSMITTING EQUIPMENT - OF Synthesisers (Decade frequency generators( MA350B VALVES - PLUGS - SOCKETS SYNCHROS Solid Stale tor use with - MA79 - RA217 - ßA1218 ETC. COURSE CIRCLE 19 FOR FURTHER DETAILS. Don't forget DS9 FORTH COMFL TN:R to visit us. You've heard that -

* Industries from brewing to aerospace use FORTH * It is easy to learn and apply * It is interactive, yet is compiled for speed * Assembler code can be included * Development is done on the target system * Your VDU, IBM compatible or BBC programs the TDS900 * TDS900 series computers have a full- screen editor * TDS900 series has both N- channel and C -MOS versions * TDS902 consumes 25mA and has 62K bytes memory * Execution times in microseconds can be measured * TDS900 cards have hardware multiply and 16 bit timer * They have interrupts, both internal and external * Some have non -volatile memory, some 9.8MHz clocks * TDS971 offers RS232 and IEEE -488 expansion * TDS972 adds RS232, A to D and parallel ports STOP PRESS STOP PRESS STOP PRE: * TDS973A gives opto- isolation on 32 input /outputs FORTH computers start at £99 Organised by Triangle Digital Services Ltd The Department of Electrical and Electronic Engineering, 100a Wood London El? 3HX The university of Leeds, Leeds LS2 9JT. 1 Fir Street, Telephone (0532) 431751 Ext. 328 T Telephone 01 -520 -0442 Telex 282284 (Ref M0775)

CIRCLE 45 FOR FURTHER DETAILS. CIRCLE 20 FOR FURTHER DETAILS. 62 ELECTRONICS & WIRELESS WORLD MAY 1986

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Transputer co- processor. rival There is a twin 800K floppy British disc interface built in and a choice of four operating for Amiga systems - CP /M68K (GEM), The new Amiga computer OS- 9/68K, Tripos and SMS -2, from Commodore with its which should enable the exceptionally fast graphics machine to run most software created a good deal of interest designed for the Amiga or the at the recent Which Computer? Atari 520ST. In addition there show. But now comes a is an SCSI bus interface for a British rival to the Amiga, the 20M -byte hard disc. Microbox 3, which on paper Other details include a real - outpaces it. time clocks, a stereo sound Microbox 3 is a colour generator, a dual RS232 port, graphics computer designed parallel printer port, mouse around the 68000 (or 68010) interface and a built-in processor running at 8MHz emprom programmer. and Motorola's Raster The board alone, is available Memory System chip set. It at £650; boxed versions of the offers 40 different screen computer with built -in disc - modes, with resolution ranging drives will be ready later. up to 640 by 500 pixels, plus Applications suggested by the features such as a 4096- colour makers include image palette, eight re- usable sprites processing, engineering work, and a virutal screen of up to video games and Kanji word - 512K in size with smooth processing. Micro Concepts, 2 horizontal or vertical scrolling. external video source. user rom. An 8M -byte plug -in St Stephen's Road, The video standard is 625 -line The board carries 512K of expansion board with a Cheltenham, Gloucestershire PAL or NTSC and the output D -RAM plus 128K of system floating -point co- processor is GL51 5AA. EWW 220 on fr can be genlocked to an rom and has room for 64K of promised. Also on the way is a Reply Card.

FF1' on the BBC A second -processor board will available to allow processing allow the BBC Micro (or many of incoming data in real time, other computers) to perform sampling at frequencies up to fast Fourier transformations 500kHz for 8 -bit resolution. very rapidly; 1024 complex The processor board, points in less than 50ms using interface and software to 16 -bit two's complement perform FFTs and design arithmetic. Magnitude scaling matching filters is all bundled is included to maintain a high together to provide a dynamic range. Computing development system for the power is provided by the TMS TMS processor in a variety of 32010 digital signal processor real -time digital signal from Texas Instruments with processing applications such 4K of program memory and as spectral analysis, finite and 64K of 16 -bit memory with infinite impulse response 100ns access time. The filters. It make a useful instruction set is optimized for teaching aid for students of Signal generators singal processing. For example digital signal processing. Two new signal generators r.m.s. Modulation is by an a 16 by 16 to 32 -bit multiply Practical applications include cover the frequency spectrum internal 1kHz tone or can be takes only 200ns and 32 -bit the possibility of recording from 10Hz to 450MHz in supplied externally. The accumulates can be pipelined sound in real time digitally overlapping ranges. The audio provision of an external crystal with the loading of the next with a resolution comparable frequency model has an socket makes it easy to use for operand. with that on compact discs; accuracy of + 3 %, generating spot frequency calibration. A hardware interface real time encryption is also sine waves up to 1MHz and Available through MS enables the transfer of data possible. square waves up to 100kHz Components Ltd, Zephyr and programs between the The hardware can be used with a rise -time of 200ns. House, Waring Street, London BBC and the TMS at about with other computers since it Output voltage is variable SE27 9LH. EWW 213 on 2Kword/s. Operation is only requires two i/o ports on from 0 to 4V, flat to within reply card. MS are part of controlled by software running the host. Enquiries about 1.5dB with an output the Steatite Group who are on the BBC. It takes adapting the interface to work impedance of 6000. also showing a range of r.f.i. assembled program data from on any host computer bus The r.f. model covers six protection and shielding discs, sends them to the TMS would be welcomed by bands from 100kHz to products; capacitor and for processing and displays the Graham Sutherland and James 150MHz on fundamentals resistors; semi -conductors, results either graphically or as Ervine, 71 Linden Gardens, extending to 450MHz on cells and batteries and many a table of numbers. London W2 4HJ. EWW 211 harmonics, with a continuously other products. Stand No. A compatible a -to -d board is on reply card. variable output of 0 to 0.1V. 219. ELECTRONICS & WIRELESS WORLD MAY 1986 63

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Compact switch -mode power Peak current may be drawn electromechanical devices that from all outputs in this 350W demand high peak power. switched -mode power supply. Powerline are displaying a The F350 is a compact, open wide range of other products frame supply that can provide including the Vicor VI100 5V at 50A, - 5V at 5A, -12V d.c. -d.c. converter that at 5A and + 24V at 5A. switches at zero volts. It is Power -failure indication is claimed to produce half the included and pulse overload heat of a conventional capability is available on all switched -mode regulator and outputs. 'Power trading' to have a minimum efficiency between the outputs is used. of 80% - typically 90 %. Meeting a number of IEC, BS, Powerline Electronics Ltd, 9 VDE and TG standards the Nimrod Way, Eglar Road, supply is intended for use on Reading, Berks RG2 OEB. computer systems with disc EWW 211 on reply card. drives, printers and other Stand No. 118. Battery- powered oscilloscope The new T0315 oscilloscope or alternate mode", and tv line from Electroplan is a dual - or frame display. It can trace 15MHz instrument operate from batteries or a.c. weighing only 4.5Kg. The low mains with internal re- weight and small dimensions chargeable batteries offering make it suitable for field up to two hours of continuous service and for application operation. Electroplan Ltd, PO where a.c. power may not be Box 19, Orchard Road, available. It has sensitivity Royston, Herts SG8 5HH. ranges from 2mV to EWW 217 on reply card. 10V /division in 12 ranges, Stand No. 132. automatic selection of chopped

Modular measurement systems Surface- The introduction of a family of selection of rom, ram and i/o training courses and on -site mount Eurocard computer products functions including disc, consultancy to ensure rapid comes from Measurement parallel, serial, isolated system development. Available connectors Systems. Modular 96 supports parallel, GPIB, analogue and through R.C.S. Microsystems to obtain best the Unix-like OS -9 operating graphics interfaces. Ltd, 141 Uxbridge Road, In order the system, giving multi -user, A key feature is that all the Hampton Hill, Middlesex benefits from surface -mounted it is necessary that all multi- tasking capability. OS -9 modules in the range are TW12 1BL. EWW 218 on p.c.b.s, can be contained in a rom and provided with OS -9 software reply card. Stand No. the components used should in can be used in turnkey at no extra cost. Support 527. mount on the surface. Erni, systems, with or without discs. includes comprehensive West Germany have come up with connectors The family includes a wide documentation, regular two -part specifically developed for surface mounting. They conform to DIN 41612 and allow the use of conventional p.c.b. size, spacing and racking. The materials used are suitable for vapour -phase and reflow soldering. Fixing holes are supplied and the makers recommended screwing or rivetting the body to the p.c.b. Available through Radiatron Components Ltd, Crown Road, Twickenham, Middlesex. EWW 214 on reply card. Stand No. 375. 64 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com ANOTHER BRICHT IDEA from A.B.I.

Are you spending hours repairing faulty printed circuit boards?

Do you find the high cost of traditional ATE cannot be justified?

Do you wish you had a low cost, simple - to -use circuit board tester that would provide a cost -effective digital test and repair facility?

If you can answer "Yes" to any of these questions, you should make a point of visiting us on Stand 493 at the All Electronics Show at Olympia, April 29th to May 1st, where we will be launching our NEW IN- CIRCUIT DIGITAL IC TESTER If you would like complimentary tickets or preliminary product information, please contact us: A.B.I. Electronics Ltd., Unit 21 Aldham Ind. Est., Wombwell, Barnsley, S. Yorks S73 8HA Tel. 0226 751639 Telex 547376 CEAG G (for ABI)

CIRCLE 37 FOR FURTHER DETAILS. SmartWatch A battery- backed real -time clock /calendar with 64Kbit non- volatile ram for under £35. This real -time clock /calendar from Dallas Semiconductor Wireless wtirld includes a battery- backed c -mos ram capable of holding data for 10 years. Send to:- E &WW SmartWatch Offer. SmartWatch keeps track of: M.S. Components, Zephyr House, Waring St., West Hundredths of seconds - seconds - minutes - hours - day Norwood London, S.E.27 9LH. - date - month - year in any computer or controller Offer applies to U.K. only. Please allow 28 days for application. delivery. Price includes data sheet. Looking like a 28 -pin socket, SmartWatch fits into a computer's 8K- by -8bit memory socket* - without any hardware modifications on most computers. To: E &WW SmartWatch Offer, M.S. Components, Zephyr House, Waring For memory read /write operations, no software modifica- St., West Norwood, London, S.E. 27 9LH. tions are required either. Please send me:- Normally the computer sees SmartWatch as a standard memory i.c. but when a special code is sent to the socket, SmartWatchlsl with memory @ 33.95 each inclusive of V.A.T., post internal address decoding triggers the clock /calendar function, and packaging.

allowing time and date information to be read and written. I enclose my cheque /p.o's value E made payable to This means that both clock and memory occupy the same E &WW SmartWatch Offer computer address range and no external decoding is required. Access /Barclaycard No is needed the clock Only a small software routine to trigger Signature function and read and write time /date information. Name Built into the socket are the real -time clock, a lithium battery, address decoding and power-down switching. Address Because of their extremely low power consumption, the 6264 -type static memory i.c. and clock /calendar remain powered for 10 years using the same battery. *JEDEC pinout Regd. in England 15137 BUSINESS PRESS INTERNATIONAL LTD., Regd. Office: Quadrant House, The Quadrant, Sutton, Surrey, SM2 5AS.

IRCLE 13 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MAY 1986 65

www.americanradiohistory.com Sowter E.M.S. POWER Transformers SYSTEMS With over 45 years' experience in the design and manufacture of several NEW IKVA hundred thousand transformers we can supply: MAINS STABILIZER AUDIO FREQUENCY AT SPECIAL TRANSFORMERS OF EVERY TYPE INTRODUCTORY PRICE YOU NAME IT! WE MAKE IT! OUR RANGE INCLUDES Microphone transformers (all types), Microphone Splitter /Combiner transformers. Input and Output transformers, Direct Injection transformers for Guitars, Multi- Secon- dary output transformers, Bridging transformers, Line transformers, Line transformers to B.T. Isolating Test Specification, Tapped impedance matching transformers, Gramo- phone Pickup transformers, Audio Mixing Desk transformers (all types), Miniature Solve all your transformers, Microminiature transformers for PCB mounting, Experimental transfor- Power Problems by contacting mers, Ultra low frequency transformers, Ultra linear and other transformers for Tran- E.M.S. sistor and Valve Amplifiers up to 500 watts, Inductive Loop Transformers, Smoothing Chokes, Filter, Inductors, Amplifier to 100 volt line transformers (from a few watts up to E.M.S. specialise in systems to eliminate your 1,000 watts), 100 volt line transformers to speakers, Speaker matching transformers power problems. all powers), Column Loudspeaker transformers up to 300 watts or more.

We can design for RECORDING QUALITY, STUDIO QUALITY, HI -FI QUALITY OR P.A. Products range from 35VA switched square wave QUALITY. OUR PRICES ARE HIGHLY COMPETITIVE AND WE SUPPLY LARGE OR 1KVA fully uninterruptible sine SMALL QUANTITIES AND EVEN SINGLE TRANSFORMERS. Many standard types are in Power Packs to stock and normal dispatch times are short and sensible. wave systems. OUR CLIENTS COVER A LARGE NUMBER OF BROADCASTING AUTHORITIES, MIXING DESK MANUFACTURERS, RECORDING STUDIOS, HI -FI ENTHUSIASTS, BAND E.M.S. also manufacture chargers which range up GROUPS, AND PUBLIC ADDRESS FIRMS. Export is a speciality and we have overseas clients in the COMMONWEALTH, E.E.C., USA, MIDDLE EAST, etc. Send for our ques- to 60 amps. tionnaire which, when completed, enables us to post quotations by return. For further details please contact: E.A. Sowter Ltd. E.M.S. Manufacturing Limited Manufacturers and Designers Chairborough Road E.A. SOWTER LTD. (Established 1941): Reg.No. England 303990 High Wycombe The Boat Yard, Cullingham Road, Ipswich IP1 2EG, Suffolk P.O. Box 36, Ipswich, IP1 2EL, England Bucks Phone: 0473 52794 and 0473 219390 Tel: (0494) 448484 Telex 987703G Sowter CIRCLE 27 FOR FURTHER DETAILS. CIRCLE 69 FOR FURTHER DETAILS. ALL -TIME CP /M MICROCOMPUTER SYSTEM BARGAIN! Fantastic bulk purchase of a major European manufacturer's entire stock of this top -quality machine enables us to retail it at far below its manufacturing cost. ALL FEATURES LISTED are INCLUDED as STANDARD: COMPLETE with EITHER single or double (as Exceptionally high quality styled keyboard with illustrated) TEAC half- height 51/4" double- sided, numeric keypad & 6 function keys Formatted double- density floppy disc drives. Centronics parallel interface capacity: 320Kb per drive. RS232/V24 serial interface selectable 300 -9600 4 MHz Z80A CPU Baud 64Kb RAM (in 4164 chips) UHF Modulator for TV, RGB & composite video output 28Kb EPROM containing monitor & MICROSOFT ROM port. (A Word- Processor ROM is available BASIC at f59 + VAT) With DUAL floppy: £199.00 (£228.85 inc. VATI With SINGLE floppy: £135.00 (£155.25 incl. VAT) CP /M Version 2.2 6 month full guarantee Carriage: £9.50 (incl. VATI Visa & Access accepted 80 x 24 display with colour block -mode graphics LOW COST PRINTERS AVAILABLE

Available ONLY from:COMPUTER APPRECIATION, 111 Northgate, Canterbury, Kent CT1 1 BH. (0227) 470512 MATMOS Ltd., 1 Church Street, Cuckfield, W. Sussex RH17 5JZ. (0444) 414484 454377 (0444) 73830 12492 CIRCLE 61 FOR FURTHER DETAILS.

LOW COST UNIVERSAL PROGRAMMER EPROMS EEPROMS MICROS

Completely self contained unit Eproms: No personality modules required. 2508/16/32/64 Controlled via RS232 serial interface. 2758 Supports Intel, Motorola and Ascii 2716/32/32A/64/64A/128/ hex data formats. 128A/256/512/513 Easily controlled by most computers. 27C16/32/64/128/256/512 Fast and standard programming modes. 68732,'64/66 Low and high byte programming for 16 bit data Byte, block and chip erase for Eeproms. Eeproms: 2816A/64A 52B13/23/33 48Z02

Micros: Price uncased £295 plus VAT. 8748/48H/49/49H 4 + 11 GHz SATELLITE TV RECEIVING EQUIPMENT LNA's LNC's RECEIVERS, FEED HORNS ETC. Dealer enquiries welcome Micra Con( epts Tel: 0242 510525 For further details contact HARRISON ELECTRONICS 2 St. Stephens Road Cheltenham Glos ' GL51 5AA 22 MILTON ROAD, WESTCLIFF -ON -SEA, ESSEX SSO 7JX Tel: (0702) 332338 CIRCLE 64 FOR FURTHER DETAILS. 66 ELECTRONICS & WIRELESS WORLD MAY 1986

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Desolderer free from static A new addition to OK Presently available at a special Industries' 'Anti- static' range offer of £3.16 inclusive - 40% of products is this desoldering off the list price. OK pump, the DP3, which Industries UK Ltd, Dutton conforms to standards of Lane, Eastleigh, Hants SO5 electrostatic -free materials. It 4SL. EWW 210 on reply has a conductive tip that is card. Stand No. 250. easy to clean and change.

Logarithmic video amp Among the products to be Total bandwidth is 30MHz. Telecomms transformers is Also included are most of the displayed by Exar the An expansion of its range of functions over a frequency XR-7000 a log video amplifier parts for a precision signal audio transformers for range of 300 to 3500Hz for i.c. with a wide bandwidth, processing system; so there is telephone coupling data and voice applications. suitable for many applications an internal band -gap applications, is the TA series Modifications to the from audio to radar and reference, a differential from Dale -ACI. All the new impedance, frequency on -chip including test instruments, summing amplifier, an models are desgined to meet response or other electrical temperature sensor and power video and audio systems, FCC part 68 requirements. A characteristics are available to regulators. Exar smoke tectors, ultrasonic supply wide range of sizes, mounting meet specific design needs. Zilos House, detectors, medical Corporation, configurations and circuits are Dale -ACI Components Ltd, instrumentation and so on. Moorbridge Road, available to provide line River Park Industrial Estate, The single -chip device has Maidenhead, Berks. EWW isolation, four -wire to two-wire Berkhamstead, Herts HP4 on reply card. Stand seven logarithmic stages 205 hybrid termination, impedance 1HL. EWW 215 on reply for No. 389. which may be cascaded matching and line balance card. Stand No. 99. increased dynamic range. Power supplies Advance Power Supplies have p.c.bs offer auxiliary outpurs extended several of their of 5, 12, 15, 18, 24 and 48V. ranges. The d.c. driven 'Power trading' between Powerflex range now includes outputs is a standard feature. a PD500 which has a nominal The Powermag A1500 is a input of 48V, but which will 5V, 300A switchmode power operate between inputs of 40.5 supply working from 110V or and 63V, believed to be the 220V a.c. inputs. These are widest input operating voltage nominal and the supply will swing in the world. Outputs operate from almost any a.c. are available in four versions: supply and input frequency. Its 5V at 60A, 12V at 30A, 24V at largest dimension is 280mm. 13A and 48V at 7A. Plug -in To complete the additions to the Advance range there are the Powerite A200 series of five -output, 200W openframe High - frequency power power supplies. They use 100kHz EELS to allow the use of small tansformers and be sensor 'highly efficient and reliable'. Marconi Instruments has The supplies operate from a.c. ;added a high- frequency, 50íZ mains and offer a main output power sensor to its range of of + 5V at 40A, with auxiliary detectors for use with its outputs of - 5V, 5A, + 12V, digital and analogue power 5A, - 12V, 5A and +24V, 8A. meters. The new sensor, 6913, in microwave, radar and Advance Power Supplies Ltd, extends the upper limit of the satellite communications. Raynham Road, Bishop's overall sensor frequency range Marconi Instruments Ltd, Stortford, Herts CM23 5PF. to 26.56Hz and a 50dB power Longacres, St Albans, Herts EWW 255 on reply card. ¡range from +20 to - 30dBm. AL4 OJN. EWW 206 on Stand no. 251. Applications for measurement reply card. Stand no. 357. ELECTRONICS & WIRELESS WORLD MAY 1986 67

www.americanradiohistory.com ECIF SHOW

waveform or a table of the Low-cost data. Graphical output can also be obtained on a pen plotter and as the data is all recorded, data logger there is not disadvantage in A comprehensive range of the slow speed of the plotter. industrial and scientific data Vela may be connected to a capture tasks can be BBC micro, an Apple II and performed by the Vela data many other computers. logger from Data Harvest. At Applications are very its heart is a 6802 processor, numerous as the instrument 8-bit d -to -a and a -to -d has been designed to be as conveters, rom software and versatile as possible. If it is 4K of battery- backed c -mos possible to use a sensor it is ram. Sockets are available possible for Vela to record the internally for additional output. Some examples are applications roms. There are structural stress analysis using four analogue inputs plus an accelerometers and pressure additional pulse input for sensors. Analysis of gases, counting, timing and recording the vibrations in Fans on triggering. Internal pulses for machinery and then analysing Assembler timing and triggering are also potential failure, using FFT provided. Various transducers etc. Data Harvest believes that show + emulator and sensors can be connected its instrument will become a Papst needs two stands - one directly to the inputs, or standard piece of lab each in the All Electronic and - instant through amplifiers and signal - equipment alongside the Electronic Production Design conditioning units which are multimeter and the shows - to display all their available as optional extras oscilloscope. They also believe air -moving products. New are development and themselves plug directly that at the low price of £375 a range of 25mm rugged a.c. to the inputs. The instrument there is no rival for use in fans and 120mm electronically can be mains or battery industry or higher education. commutated d.c. models. Also Developing object -code system powered and the recorded data The instrument is also being on display is an "intelligent" software for a target is retained in memory for later marketed under their own cooling system that can presents problems. However downloading. Vela's programs name by a well -known automatically control d.c. fans one solution is to use an are selected by simple push- component distributor and is to suit varying requirements of eprom emulator. Such a device one port button instructions, selected featured as a new product in ambient temperature and is the Portal emulator the front panel. These include the latest edition of their operating load. Papst Motors of which plugs into the transient recording, data catalogue. Data Harvest Ltd, Ltd, East Portway, Andover, development system and the collection, timing, pulse 28 Lake Street, Leighton Hants SP10 3RT. EWW 208 other to the target. Portal has counting and waveform Buzzard, Beds LU7 8RX. on reply card. Stands no. the advantage of being generation. Channel number EWW 222 on reply card. 101 and 1031. developed by Andy Green, and required parameters are who also wrote the Meta all selected through the assembler - and of being membrane keyboard and cheap. When a program is shown on the led display at assembled by Meta, in the the top of the panel. After an machine code of the target event is captured it can be system, the object code is stepped through with the immediately available on the recorded values being target and may be run displayed on the leds. All of instantly. Meta can translate a the four channels can be used program into machine code for simultaneously. all the popular 8 -bit processors The instrument can also (68000 is under development). output its data to an analogue This means that the oscilloscope or a Meta /Portal combination can microcomputer. Both can be used on a wide variety of display the recorded waveform target processors and is not and it is possible to step dedicated to one specific through he sequence to get system. Up top four Portals spot values at the cursor. This can be chained together and has the added advantage of addressed individually and can turning the laboratory be used in sockets for a 2716 oscilloscope or micro into a up to a 27512 i.e. 64Kbyte. digital storage oscilloscope. Two may be used together, The micro has the addition one each for the high and low advantage of being able to data strobes of a 68000 store the recorded events as system. The system runs from micro waveforms or as tables of the user port on a BBC data, make comparisons and with no hardware is two perform such analyses as FFT modification. Meta on roms. Barrier. Freepost and statistics. The data can Crash a printer to Flitwick, Bedford MK45 1YP. also be output to EWW 219 on reply card. obtain a graph of the 68 NICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com TEST EQUIPMENT RALFE ELECTRONICS * COMPUTER PERIPHERALS * BIRD 43 Wattmeter 10 CHAPEL STREET, LONDON, £75 +VAT NW1 TEL: 01 -723 8753 1.6MB 8" FLOPPY DISC DRIVES New KNIGHT SWEEP GENERATOR 3- 220MHz - £150 + VAT Stock AIRMEC 10KV Ionisation tester E85 + VAT BRAND NEW At a AIRMEC 20KV surplus price, Fully Shugart compatible 'MFE IONISATION TESTER 209 CORPORATION' Model M-700 001181E-SIDED industry standard 5' 150 + VAT Floppy disc drives. Double -density. up to 1 5MBytes. Power BRUEL & KJOER Voltmeter 2409 E 60 requirements ±5V and . 24V e 1.1A. 240V. AC 50Hz. SULLIVAN Inductance bridge R400. Measures L to LOWEST PRICE EVER,£160 - INC. VAT. CARRIAGE 8 HANDBOOK. 11.11H discrimination .002uH E375 + VAT GENERAL RADIO Capacitance bridge 1617A DRE 4000A DRIVES E125 +VAT BPL RC &L Component comparator with in /out limites Data Recording Equipment Model 4000A 5 + 5 MB Top - indicator unit £250 + VAT loading disc drives in stock. Brand new including full HEWLETT -PACKARD 3465A OMM technical manual. Few remaining £250 each + VAT. E125 TELEQUIPMENT D83 50MHz f425+VAT BIRD 4370 Thurline Wattmeter f 135 +VAT TELEQUIPMENT DM84 10MHz Storage E275 * MULTI -RAIL LINEAR PSU's * TELEQUIPMENTD65&D68 175, E225 POLYSCOPS I SWOB & II E250/450 + VAT TELEQUIPMENT BOONTON D67A 25MHz E250 Recent stock of brand new COUTANT ESM- Series Power Supplies at 77B Capacitance limit bridge TELEQUIP 083 15MHz 3.trace E225 surplus Model ESM15.2 giving regulated, stabilised DC E175 +VAT FARNELL 12MHz prices. dual 200 outputs 5V a 15A and to 1.5A GEN RAD Oscillator 450- 1050MHz DYNAMCO 30MHz 212V í15V a each and an un- D7100 E225 stabilised 24V a 2A. 240V AC input. Measures Fully f 95 +VAT 5 =5x11'. GEN RAD enclosed. In original cartons with handbooks. £45 each VAT N 1606A RF Bridge E125 +VAT carnage AMBER Audio BRUEL & KJOER C51 4400 test set Et 1 50+ VAT MARCONI TEST EQUIPMENT DATRON 1051 DMM E350 +VAT SYSTRON DONNER power unit. 0-50V in 5 decades Frequency response tracer 4712 E295 HP SPECTRUM ANALYSER 1.2GHz Microphone amplifier 2603 E100 BFO 0-1A Current limited f 12 E FEEDBACK INSTRUMENT 'CYGNET 312' 1013 E145. BFO 1022 E175. Voltemeter 2409 C75. Voltmeter 241 5 E75. Hewlett Packard Spectrum Analyse, Telewriters E 500 /pair I ° :t Model 8554L (100KHz- 1250MHzl ;:F-: with I.F. Section model 8552L in main R&S POLYSCOPS a raa HEWLETT-PACKARD I e frame type 140A. (Similar to illustration EQUIPMENT Rohde & Schwarz Model SWOB II but non -storage main-frame). POLYSCOPS IN STOCK in tested working Sold in excellent full -working condition TF2370 SPECTRUM ANALYSER with additional HEWLETT -PACKARD 3490A DMM 350 condition available for just E200 each. as 5K spare main frame E3250.+ VAT HEWLETT- PACKARD 3465A DMM we are requiring space for urgent TF2300 AM /FM Modulation metersf400 E125 stock TF2331 HEWLETT-PACKARD 8405A Vector Voltmeter.....f 1000 delivery. This price will not be repeated!! Distortion meter 400 TF144H HEWLETT -PACKARD 808- series sig'gens' E75-195 Check prices elsewhere in this meg' & Series generators from HEWLETT -PACKARD 606A signal generator E75 then order & COLLECT for E200 each. NB E75 -E150 8" SHUGART DISC DRIVES HP 141T Spectrum analyser. Phone for low quote) This is the SWOB II model to 1200MHz. TF888 Universal bridge £75 wanted for HP 8551 Analysers -B WOs For this price no RF connectors or probes TF2301 Programmable Mod'meter.E250 GENUINE ALSO REQUIRED FOR STOCK GOOD 851/8551s. included in price but all in full working TF2607 AC /DC Voltmeter E200 SHUGART MODEL HEWLETT -PACKARD 1707A 75MHz oscilloscope f800 nrrlerl TF1245 0 -Meter & oscillators E575 SA800. Soft -sectored single- TF10668/1 sided industry TRANSVERTERS-240V 50Hz input to AM /FM Sign gen standard 8' 10- 470MHz E450 I floppy disc drives. 800kB 115/230V 60Hz Output @ 250 Watts. E 300 TF995B/5 AM /FM sign gen storage. Supplied in excellent ESCAP DC MOTORS 1.5- 220MHz £425 ,condition, little -used. Remove.: DISPLAY SCOPES TF1 Q64 AM /FM sign gens £95 from fully functional equipme- Price including VAT, Swiss-made 6V TF2804 Electronic Voltmeter E125 carriage precision DC motors with 70 1 reduction gearboxes Amnec/Racal 4-channel display osciiloscopes for giving final drive TF893A Audio power meters E85 and Zerox of handbook - £95 speed of 16RPM is 6V. Diameter 2'bcros x 4cros colleges. educational etc. 17-CRT DC - 1010u. Fully long. PRICE INC. VAT 8 CARRIAGE TF2700 Universal bridge E250 C5.25 operational. £125 +VAT TEKTRONIX 4907 FILE MANAGER + (Ex- equip. tested 8 guaranteed). TF2000 Audio sig gen /attenuator f 175 E150 VAT TF2330 Wave analyser audio 350 SA801 Shugart drivq exerciser E100 MAINS CONDITIONERS TF2002 MF /HF AM sign generator f400 Constant -voltage transformers TF791D Deviation meter f 175 AMIFM SIGNAL GENERATORS TF2608 Differential DC STEPPER MOTORS SOLA 230V 1 KW cvt....f95 + VAT Voltmeter f 125 ** ** ADVANCE TF1152A RF power meters 25W E75 230V 500W E75 + A bulk buy of the MARCONI TF995A/5 generators rand new stock of 'ASTROSYN' Typa 20PM- CLAUDE LYONS 3KW f175+ TF2162 Attenuator f100 Signal enables us to offer them at a ridiculously low price. A055 stepper motors. 28V DC. 24 steps per res. SERVOMEX5KW TF2430 80MHz counter f 1 50 f175+ Specification includes 1.5- 220MHz frequency coverage 15 oz -in torque (a 100PPS. Body length SERVOMEX 3KW E125+ 21/2", FM Deviation 0 -5KHz & 0- 15KHz, 3 mod'frequencies, AM diameter 2 ", shah t/." diam x 41/4" spirally + carriage on any type E 10 each. to 50 %. threaded. Stepped a variable incremental tuning, stability Weight t6oz. Price each £11.501p &p 0.002% frequency drift. Course & fine attenuation from PLEASE NOTE: All our used equipment is 50pí. Connections sold in lull working condition and carries a 90 day war- 1 supplied. INC. VAT. uV -10omV to within 1 db. ranty For our mail -order customers, we offer a money back if not satisfied guarantee. Supplied in fully operational condition for f225 INC. VAT. OFFICIAL ORDERS ACCEPTED FROM GOVERNMENT BODIES ETC. Carriage n- f 5. INB This price cannot be repeated).

CIRCLE 74 FOR FURTHER DETAILS. HART - The Firm for QUALITY

LINSLEY HOOD 300 SERIES AMPLIFIER KITS Superb, HART designed, integrated amplifier kits derived from Linsley -Hoods articles in 'HiFi News'. Ultra easy assembly and set -up with sound quality to HóiLh please the most discerning listener. Ideal basis for any rIg ht domestic sound systems if quality matters to you. Buy the complete kit and save pounds off the individual component price. K300-35. 35 Watt. Discount price for Complete Kit £98.79 K300-45. 45 Watt. Discount price for Complete Kit £102.38 RLH4 &5. Reprints of Original Articles from 'HiFi News £1.05 no VAT

LINSLEY -HOOD CASSETTE RECORDER CIRCUITS Complete very high quality low noise signal handling stages for any stereo cassette recorder. Separate record and replay sections for optimum performance. Switched bias and equalisation to cater for chrome and ferric tapes. Very easy to assemble on plug -in PCBs. Complete with full Forth and Engineers instructions. K800 Complete Stereo Record/Play Kit The programming Ftllrth'phts £33.70 language Forth has 860X Stereo Mic Amp Kit to suit £8.70 much to offer electronics engineers wishing CrOss Compilation RLH 1 &2 Reprints of original Articles 75p no VAT to develop microprocessor based boards running specialised applications. Normally. STUART TAPE RECORDERCIRCUITS assembler or machine code would be used *404 iltn(flt3ÇtivE Si>ftwäre Complete stereo record, replay and bias system for reel -to-reel recorders. These circuits will give and ROMmed. Forth can give substantial studio quality with a good tape deck. Separate sections for record and replay give optimum per- advantages over this approach, such as w IiätÖwars formance and allow a third head monitoring system to be used where the deck has this fitted. programming at both machine and high Standard 250mV input and output levels. *: (3l9tld:âliÇt.ÇÖitYpg: r! r OSs levels, rapid and interactive development of K900W Stereo Kit with Wound Coils and Twin Meter Drive £65.67 code, and high speed and compactness. A Nnkat allows RJS1 Reprints of Original Articles £1.30 no VAT cross compiler will then allow a Forth dëslgggaq r3t}ppkcalìattor application developed and debugged on a HIGH QUALITY REPLACEMENT CASSETTE HEADS particular operating system, such davet000000.00 bs;lQft2ti artry Do your tapes lack treble) A worn head could be the problem. as on a Tape heads desktop micro, to be transferred RONEmsd 3ts;ö tätg&: are constantly improving and fitting one of our latest to run on a stem replacement heads given processor in ROM. could restore performance to better than newt Standard mountings fit most decks and our TC1 Test Cassette will' make it easy to set the azimuth spot on. As we are . zPS48;:i?; tvs6aU, pCC7CJS the actual % WORK FORTH MSDOS or CPM £48.00 importers you get prime parts at lowest prices. All our heads are 4= vMB, ::MOONt)ËX;NO-S, suitable for Dolby machines. extensions View -trace fx4. or t7 £5f7 Aet core ( b.t} only HC20 Permalloy Stereo Head. Good quality Floating standard head fitted as original equipment on many Point £35.00 decks £5.11 HS FORTH MSDOS £230.00 HS16 Sendust Alloy Super Head. Quite simply the best. Longer life than permalloy, higher output FORTH 09 FLEX or 0S9... £175.00 than ferrite, fantastic frequency response £9.91 `*$OW#4:81?7.0i lEi. 6502. HQ551 4 -Track head for auto -reverse or quadrophonic use. Full specification record and play SUMMER COURSES -3 day rE35i1::w63Q3. head £9.73 introductory and advanced Forth Full data on these and other heads in our range are contained in our free list...... courses with notes and working HART TRIPLE- PURPOSE TEST CASSETTE TC1 software One inexpensive test cassette £375.00 For further information, enables you to set up VU (Dolby) level, head azimuth and tape contact: speed without test equipment. Vital when fitting new heads. Complete with instructions £4.86

We are the Forth specialists, we also MicroProcessor Send for your FREE copy of our lists with full details of our complete range of Kits, Components, stock a large range of books, listings, Engineering Ltd PCBs, Cassette Heads and Decks: - Overseas please send 5 IRCs for Airmail Post. and implementations for machines 21 Hanley Road, Shirley Please incld part cost of Post, careful packing and insurance as follows: Orders up to £ 10 - 50p, ranging from Amstrad to Atari ST, Southampton SO1 5AP .1111. orders £10 to £49 - £1, orders over £50 - £1.50. IBM PC to PDP11. Tel: 0703 780084 I=1:: C KITS CIRCLE 39 FOR FURTHER DETAILS. 1, Penylan Mill, Oswestry, Shropshire SY 10 9AF 24 hr SALES LINE 106911 652894 Please add VAT CIRCLE 54 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com O1- 208 1177 TFCHNOMATIC LTD 01-208 1177 BBC Computer & Econet Referral Centre DISC DRIVES PD800P (2 x 400K/2 x 640K 40/80T DS) with built in Monitor stand £289(a) AMB1 5 BBC MASTER Foundation computer 1 28K £435 (a) PD800 (2 x 400K/2 x 640K 40/80T DS) £269(a) AMB1 2 BBC 1 MASTER Econet computer 28K (only ANFS) £348 (a) TS400 1 x 400K/1 x 640K 40/80T DS £119(b) A MC06 Turbo 165C- 02) Expansion Module £107 (b) PS400 with psu 1 x 400K 40/80T DS £139(b) ADF13 Rom Catridge £13 (b) ADF10 Econet Module E43 (c) ADJ22 Ref. Manual Part 1.114.50 lc) ADJ23 Ref. Manual Part 11114.50 (c) 3.5" Drives ADJ24 Advanced Ref. Manual £19.50 )c) 1 x 400K/1 X 640K 80T DS TS35 1 £115 (b) PS35 1 with psu £1301b1 BBC Dust Cover £450)d) 1 770 DFS Upgrade for Model B £43.50)d) 2 x 400K/1 x 640K 80T DS ADFS ROM (for B with 1 770 DFS & B plus) 64K Upgrade Kit for B plus £35 Id) TD352 £205(b) PD35 2 with psu £220(b) ACORN Z80 2nd Processors £329 (a) 6502 2nd Processor £162)b) MULTIFORM Z80 2nd Processor £299 (b) 3M FLOPPY DISCS TORCH Z80 2nd Processor ZEP 100 £199 (a) Industry Standard floppy discs with a lifetime guarantee Discs in packs of 10. TZDP 240: ZEP 100 with Technomatic PD800P dual drive with built -in monitor stand£469 (a) 51/4' DISCS 31, DISCS META -ASSEMBLER. Both an editor and Macro -Assembler. Meta can assemble 40TSSDD £10:50(d) 40TDSDD £12:751d) 80TSSDD E18(d) most 65xx, 68xx, 6804, 6805/6305, 6809, 8048, 8080/8085, Z80, 80TSSDD £14:75(d) 80TDSDD £16:00 (d) 80TDSDD £25(d)

1 802 and more. Please phone for comprehensive leaflet. Meta -Assembler £ 126(c) FLOPPICLENE DRIVEHEAD CLEANING KIT We stock the full range of ACORN hardware and firmware and a very wide FLOPPICLENE Disc Head Cleaning Kit with 28 disposable cleaning discs range of other peripherals for the BBC. For detailed specifications and pricing ensures continued optimum performance of the drives. 51" £14.50(d) please send for our leaflet. £16.00(d) DRIVE ACCESSORIES 3" PRINTERS & PLOTTERS Single Disc Cable £6 (d) Dual Disc Cable £8.50 (d) EPSON: LX NLQ £195 Optional Tractor Feed E20 (c) -80 (a) 10 Disc Library Case £1.80 (d) 30 Disc Storage Box £6 (c) EPSON FX RANGE FX85180 col) £315 (a) FX105 1136 col) £449 (a) 30/40 Disc Lockable Box £14 (c) 100 Disc Lockable Box £16(c) EPSON JX80 4 colour printer £435 (a) EPSON LO Range: LQ800 180 col) £595 (a) LQ15001136 col) 2Kbuffer £875)a) MONITORS 32K buffer £950 (a) All 1 4" monitors now avi(able in plastic or metal cases, please specify your TAXAN: requirement. KP810180col) £160(a) KP910 (1 56 col) £339 )a) 14 "RGB 1431 STD Res £ 179 (a);1451 Med Res E229 (a); 1441 Hi Res £375 (a). DAISY WHEEL: BROTHER HR1 5 £285 (a) JUKI 6100 £289 (a). 14" RGB with PAL & Audio 1431 AP Std Res £199 (a) 1451 AP Med Res £275 (a) CENTRONICS GLP INLQ) Printer E109 (b) Tractor feed £14 (d) Swivel Base for Plastic 14" Microvitecs £20 (cl DOTPRINT. + NLQ Rom for Epson £28 (d) Epson HI -80 PLOTTER £325 (a) Integres Colour Printer £569 (a) 20" RGB with PAL & Audio 2030CS Std Res £380 (a); 2040CS Hi Res £685 (a). PRINTER ACCESSORIES TAXAN 12" RGB SUPERVISION III £330 (a) We hold a wide range of printer attachments (sheet feeders, tractor feeds etc) in stock. Serial, parallel, IEEE and other interfaces also available. Ribbons MITSUBISHI 1 4" RGB Med RES IBM & BBC Compatible £249 (a) available for all above plotters. Pens with a variety of tips and colours also MONOCHROME MONITORS: available. Please phone for details and prices. TAXAN KX1201G Hi Res 12" Etched Green Screen £90(a) Plain Fanfold Paper with extra fine perforation (Clean Edge): TAXAN KX1203A Hi Res 1 2" Etched Amber screen £105 (a) 2000 sheets 9.5' x 11' £13(b) 2000 sheets 14.5' x 11' £18.50(b) PHILIPS BM7502 1 2" Hi Res Green Screen £75 (a) Labels per 1000s: Single Row 3§' x 1 7/16' £5.25(d) Triple Row 2 -7/16' x 1 7/16' £5.00(d) PHILIPS BM7522 1 2" Hi Res Amber Screen £79 (a) BBC Leads RGB £5(d) Microvitec £3.50m Monochrome £3.50 (d) MODEMS (d) MIRACLE WS 2000 UVERASERS PRINTER BUFFER The world standard BT approved modem covering all standard CCITT and UV1T Eraser with built -in timer and mains indicator. The buffer offers a storage of 64K. Data from three BELL (outside UK only) standards upto 1200 baud. Allows communication Built -in safety interlock to avoid accidental exposure computers can be loaded into the buffer which will with virtually any computer system in the world. Expandability to Auto to the harmful UV rays. continue accepting data until it is full. The buffer will Dial and Auto Answer with full software control enhance the considerable Scan handle up to 5 eproms at atime with an average automatically switch from one computer to next as erasing time of about 20 mins. £59 + £2 p&p. soon as that computer has dumped all its data. The features already provided on the modem. Mains powered. WS 2000 £102 UV1 as above but without the timer. £47 + £2 p &p. computer then is available for other uses. LED bar - (b), Data Cable £7(d), For Industrial Users, we offer UV140 & UV141 era- graph indicates memory usage. Simple push button sers with handling capacity of 14 eproms. UVI 41 has control provides. REPEAT, PAUSE and RESET WS RANGE the new professional series. All are intelligent a built in timer. Both offer full built in safety features functions. Integral power supply. £199 (a). NEW -3000 - UV140 £69, UV141 £85, p&p £2.50. and 'Hayes' compatible, allowing simply 'English' commands to control BBC Cable Set £30. its many features. All models feature Auto -Dial with 10 number memory, Serial Test Cable Serial Mini Patch Box Serial Mini Test Auto -Answer, Speed buffering, printer port, data security option etc. All Serial Cable switchable at both ends Allows an easye method to Monitors RS232C and CCITT models are factory upgradeable. allowing pin options to be re- routed or reconfigure pin functions V24 Transmissions, linked at either end - making it possible without rewiring the cable indicating status with dual WS3000 V2123 (V21 & V23 + Bell £295 (a) WS3000 V22 (as above plus 1200 lo produce almost any cable assay. Jumpers can be used colour LEDs on 7 most baud full duplex £495 (a) WS3000 V22bis (as above plus 2400 baud full configuration on site. and reused. £22 (d) significant lines. Connects in duplex £650 (b) Available as M/M or M/F £24.75 (d) Line £22.50 (d) BBC Data Cable for WS3000 £6(d). Data Cables for other micros available CONNECTOR SYSTEMS The WS3000 range all have BT approval. EDGE AMPHENOL RIBBON CABLE I.D. CONNECTORS CONNECTORS (grey /metre) GEC DATACHAT 1223: An economically (SOeedblock CONNECTORS 36 way plug Centronics 10-way 40p 34 -way 160p re Edge priced BABT approved modem complying No of seder Recap-cep- 0.t 0.156' (solder 500p (IDC) 475p 16-way mp 40 -way 180p wave PI asp Co . with CCITT V23 standard capable of 2 x 8-way (commodore) - 300p 36 way skt Centronics 20 -way 85p 50 -way 200p 2 x 10-way 150p (solder) 550p (IDC) 500p 120p 64 -way 20 145p 1259 195p 26 -way 28p operating at 1200/75bps and 75/1200bps 2 x 12-way 201 3509- 26 175p 150p 240p Ivi: - 24 way plug IEEE (solder) is 2 x 18-way 140p and 1200 /1200bps pseudo full duplex. It 34 200p 160p 3209 - 475p (IDC) 475p x (ZX811 175p 220p 40 220p 190p 3409 2 23-way line powered does not require external 25-way 225p 220p 24 way skt IEEE (solder) 50 235p 200p 390p 2 x DIL HEADERS power source. it is supplied with software 2 x 28-way (Spectrum) 200p - 500p ((DC) 500p 2x36-way 250p - PCB Mtg Skt Ang Pin Solder IDC suitable for connecting to PRESTEL, 1x43-way 260p - 24 way 700p 36 way 750p 14 pin 40p 100p Micronet 800, Telecom Gold and a host of D CONNECTORS 2 x 22-way 190p - 16 pin 50p 110p 2 x 43-way 395p 18 pin 60p £86(b) No of Ways 50op GENDER CHANGERS - bulleting boards 1 x 77 was 400p 20 pin 75p 9 15 25 37 2 x 50-way(S100conm 600p 25 way D type 24 pin 100p 150p II MALE: SOFTY 28 pin 160p 200p This low cost intelligent eprom programmer can program 2716, 2516, Ang Pins 120 180 230 350 Male to Male £10 EURO CONNECTORS 40 pin 200p 225p 2532, 2732, and with an adaptor, 2564 and 2764. Displays 512 byte Solder 60 85 125 170 Male to Female £10 DIN 41612 Plug Skt page on TV has a serial and par- IDC 175 275 325 Female to Female... £10 - - X Pin 275p allel I/O routines. Can be used as an emulator, cassette interface. FEMALE: 2 32 way St zlup Softy!' £195.00)b( St Pin 100 140 210 380 2 X 32 way Ang Pin 275p 320p ATTENTION Adaptor for 2764/ Ang Pins 160 210 275 440 3 X 32 way St Pin 260p 300p RS 232 JUMPERS £25.00 3 X 32 way Ang Pin 400p All prices in this double page 2564 Solder 90 130 195 290 (25 way DI IDC 195 325 375 - IDC Skt A + B 400pp 24 Single end Male £5.00 advertisment are subject to SPECIAL OFFER St Hood 90 95 100 120 IDCSk)A+C 24" Single end Female £5.25 change without notice. 130 150 175 24" Female Female £10.00 2764 -25 £2:00(d); Screw - For 2 X 32 way please specify 24" Male Male £9.50 ALL PRICES EXCLUDE VAT 27128 -25 £2:50(d); Lock spacing (A + B, A + Cl. 24" Male Female £9.50 Please add carriage 50p 6264 LP-15 £3:40(d); unless indicated as follows: TEXTOOL ZIF MISC CONNS DIL SWITCHES (a) £8 (b) £2.50 (c) £1.50 (d) 105p INDUSTRIAL PROGRAMMER SOCKETS 24 -pin f7.50 21 pin Scart Connector 200p 4 -way 90p 6 -way £1.00 ACORN IEEE INTERFACEE278(a) 10 150p EP8000 E695 (a) 28-pin E9.10 40-pin E12:10 8 pin Video Connector 200p 8 -way 120p -way Using 'Preste(' type protocols. For information TECHNOLINE VIEWDATA SYSTEM. TEL: 01 -450 9764 and orders - 24 hour service, 7 days a week

70 ELECTRONICS & WIRELESS WORLD MAY 1986

www.americanradiohistory.com 74 SERIES 74C SERIES 74273 2.00 74LS273 1.25 4076 0.65 LJNEAR ICs 74276 1.40 74LS279 0.70 4077 0.25 COMPUTER COMPONENTS 700 0.30 74278 1.70 74LS280 1.90 4078 0.25 AD758112.r LM710 0.48 A41: 14.00 TMS4500 14.00 KEYBOARD 7401 0.30 74279 0.90 74LS283 0.60 081 0.24 cP EPRar4s 75154 1.20 74C00 0.70 ADC0808 11.90 LM711 1.00 TBA231 1.21 TMS9901 5.00 ENCODERS 7402 0.30 74283 1.05 74LS290 4082 0.25 75159 220 0.80 74C04 0.60 AM7910pC 25.00 LM723 0.60 78A00 0.80 102CE 6.50 TMS9902 7403 0.30 74742 3.20 74LS292 5.00 2516+5V 3.50 75160 5.00 9.00 74C08 0.70 AN -I 5050 110 1M725CN 3.00 10A810 0.90 2650A 10.50 TMS9911 7404 0.36 74290 0.90 74L5293 4086 0.75 18.00 2516-35 5.50 75161 3.50 AY52376 11.50 0.80 74C10 0.70 AY-3-1350 3.50 LM733 0.65 38420 0.80 6502 4.50 TMS9914 4089 1.20 14.00 2532 4.50 AY53600 7.50 7405 0.30 74293 0.90 74L1295 1.40 74C14 0.60 AY.3-8910 4.90 LM741 0.22 TBA820M 0.75 65CO2-2MHz 75162 4.00 7406 0.40 74298 1.80 74L5297 4093 0.35 2532-30 5.50 75172 3.00 74C922 500 9.00 74C20 0.70 AV-3-8912 5.00 LM7747 0.70 T8A920 2.00 12.00 Z80PIO 7407 0.40 74351 2.00 74LS298 4094 0.90 2.50 2566 8.00 75182 0.90 74C923 6.00 1.00 74C32 1.00 CA3019A 1.00 LM748 0.30 TBA950 2.25 6502A 6.50 280APIO 2.75 7408 0.30 74365A 0.60 74L5299 4095 0.95 75188 0.0 2.20 74C42 1.50 CA3020 3.50 LM1011 4.80 TC9109 5.00 65026 8.00 ZBOCTC 2.50 CA3028A 1.10 LM1014 1.50 TCA210 3.50 6800 2.50 280ACTC 2.75 0.30 0.80 2.70 2716+5V 3.50 75365 1.50 gg RAT0 CA3046 0.70 LM1801 3.00 TCA220 3.50 6802 3.00 Z800001 6.50 74110 7 4098 0. 2716-35 5.50 75450 0.0 GÉNUERÁIORS 0.30 376A .0 74LS323 3.00 74C74 1.20 GA3069 3.25 LM1830 2.50 TCA270 3.50 6803-2 12.00 4099 ZBOADART 7.00 2732 4.0 75451 7412 0.30 74390 1.10 74LS324 3.20 74C76 1.00 0.99 CA3060 3.50 LM1871 3.00 TCA940 1.75 6809 8.0 0.50 7413 0.50 74393 1.20 74LS348 4501 0.36 2732A-2 9.50 75452 0.50 MC14411 7.0 2.00 74C83 2.00 CA3080E0.70 LM1872 3.00 TDA10040 5.00 6809E 10.00 280DMA 7.00 7414 0.70 74490 1.40 74L5352 1.20 74C85 2.25 4502 0.55 75453 0.70 COM81168.0 4503 CA3085 1.50 LM1886 6.00 TDA1o10 2.25 68809 10.00 ZBOADMA 7.50 7416 0.36 74L5353 1.20 74C86 0.50 0.36 CA3086 0.60 TDA1022 4.50 75454 0.70 40728 7.50 LM1889 4.50 68B09E 12.00 2732A-30 100 7417 0.40 74L5356 2.10 74C90 1.90 CA3089E2.50 TDA1024 1.10 75480 1.0 LM2917 3.00 88000-LB 36.00 2804610/0/2/9 2732A-35 7420 0.30 7415363 1.80 74C93 4 05 3.60 550 ; 75491 0.65 1.50 CA309040 3.75 LM3302 0.90 TDA11706 3.00 7.00 7421 0.60 74L5 SERIES I76LS3641.0 74C95 4506 0.90 2764-25 2.00 75492 0.85 UARTS 1.60 CA3130E0.90 LM3900 0.80 TDA20023.25 8035 3.50 ZBOBPIO 5.00 7422 0.38 74L5365 0.50 74C107 1.00 4507 0.35 27C&-2510.00 CA3130T 1.30 LM3909 1.00 TDA2003 1.90 80C35 8.00 2808CTC 5.00 4508 8726 1.20 AY31015P 3.00 7423 0.36 74LS00 0.24 74L5366 0.50 74C150 5.00 CA3140E 0.45 LM3911 1.80 TDA20042.40 8039 4.20 280BDART 0.00 27128-2512.50 0T28 7425 0.40 74L501 0.24 74L5367 0.52 74C151 2.00 U s20s CA310T 1.00 LM3914 3.50 TDA20063.20 80C39 7-00 1.20 AY51013P 3.0 27258-25 20.00 8795 7426 0.40 74LS02 0.24 74LS368 0.50 74C157 2.50 4511 0.55 CA310 2.25 LM3915 3.40 TDA20203.20 8080A 4.20 1.20 COM8017 3.00 4512 0.55 27258-30 20.00 8793 1.20 1M6602 4.0 7427 0.32 74LS03 0.24 74LS373 0.90 74C160 1.80 CA310E 1.50 LM3916 3.40 TDA20302.50 8085A 3.00 4513 MEMORIES 17268 12.00 8797 1.20 7428 0.43 74LSO4 0.24 74L5374 0.90 74C161 1.80 150 CA3161E 2.00 LM13600 1.50 TDA25935.00 80085A 7.50 4514 1.10 27512 P.O.A 8798 1.20 7430 0.30 74LSO5 0.24 74L5375 0.75 74C162 1.80 CA3162E6.00 M51513L 2.30 TDA26537.00 8086 22.00 216-150 4.00 7432 0.36 74L508 0.24 74L5377 4515 1.10 TMS27165.00 81L595 1.40 1.30 74C163 1.60 CA3189E 2.70 M51516L 4.50 TDA35607.50 8088 17.50 2101 4.00 MODULATORS 7433 0.30 74L509 4516 0.55 81L596 1.40 0.24 74LS378 0.95 74C173 1.00 CA320E 1.50 MB3712 2.00 TDA3810 7.50 P102 2.50 7437 0.30 74L510 0.24 74LS379 74C174 4517 2.20 1.30 1.50 CA3280G 3.00 MC1310P 1.50 TDA70003.50 8741 15.00 21078 5.00 6MHz 3.75 7438 0.40 74LS11 6518 0.48 07002 CONTROLLER 81LS98 1.40 0.24 74LS381 4.50 74C175 1.50 6.00 1413 0.75 TEA1002 7.00 8748 16.00 2111A-35 4.00 8MHz 4.50 7439 0.40 74L513 4519 0.32 DAC1408-83.00 881S120 3.00 0.34 74L5385 3.25 74C193 1.50 MC1458 0.45 TL061CP0.40 2114 2.50 7440 0.40 74L514 74LS390 4520 0.60 CRT5027 18.00 0.50 0.60 74C194 1.50 DAC08003.00 MC1495 3.00 TL062 0.60 11451601 12.00 2114-2 3.50 7441 0.90 74LS15 0.24 74L5393 1.00 74C195 1.50 DAC08083.00 TL064 CR75037 12.00 9602 300 MC1496 0.70 0.90 TMS9980 14.50 CRT6545 9.00 7442A 0.70 74L520 0.24 74LS3954 1.00 74C221 2.50 4522 0.0 DG308 3.00 TL071 0.40 9636A 1.60 SOUND MC3340P 2.00 TMS9995 12.00 2147 4.00 EF9364 8.00 9637AP 180 VISION 7443A 1.00 74LS21 0.24 74LS399 1.40 74C244 2.00 4526 0.70 HA1366 1.90 MC3401 0.70 TL072 0.70 7444 1.10 74LS22 0.24 74L5445 1.80 74C245 2.25 4527 EF9365 25.00 CL7106 6.75 MC303 0.85 TL074 1.10 Z80 2.50 4116 2.00 EF936625.00 12MHz 12.00 7445 1.00 74LS24 0.50 74L505 1.20 74C373 2.25 p, 9638 1,90 CL7611 0.95 MF1OCN 4.10 TL081 0.35 280A 2.90 4116-20 1.50 EF9367 36.00 74460 1.00 74LS26 0.26 74LS467 1.20 74C374 2.25 4529 1.00 CL7650 4.00 MK502409.00 TL082 0.55 Z806 5.50 MC6845 6.50 7447A 1.00 74L527 0.24 74LS490 1.50 74C902 1.20 4531 0.75 CL7660 2.50 TL083 0.75 MK50398 11.00 Z80H 7.50 41256-207 0.50 MC6845SP 6.50 7448 1.00 74L528 0.24 74LS540 1.00 74C911 9.00 4532 0.65 CL8038 4.00 TL084 1.00 CRYSTALS ML902 5.00 41256-157 0.50 MC6847 8.50 DISC 7450 0.36 74LS30 0.24 74LS541 1.00 74C912 4.50 4534 3.80 CM7216822.00 TL094 2.00 SUPPORT ML922 4.00 DEVICES SFF96364 8.00 CONTROLLER 32.768KHZ 1.00 7451 0.35 74LS32 0.24 74L5608 7.00 74C922 6.00 4536 2.50 CM7217 7.50 TL170 0.50 MM6221A 3.00 4164-15T1 3.00 TMS9918 15.00 ICs 1.00MHz 170 7453 0.36 74LS32 0.24 74LS61019.00 74C923 8.50 4538 0.75 CM7555 0.00 NE529 TL430C 1.20 2.20 2651 12.00 4164 2.00 TMS9928 10.00 1.6432MHZ 2.25 7454 0.38 74LS33 0.24 74LS612 19.00 74C925 6.50 4539 0.75 CM7556 1.40 UAA1003-39.35 NE531 1.20 3242 8.00 4164-20 2.00 TMS9929 10.00 765A 13.00 2.00MHz 125 7460 0.55 74LS37 0.24 74L5624 3.50 74C926 7.50 4541 0.90 LC7120 3.00 UA759 3.20 NE544 1.90 3245 4.50 4416-15 3.50 6843 8.00 2.4570MH0LI 7470 0.50 ' 74LS38 0.24 74L5626 2.25 4543 0.70 LC7130 3.00 UA2240 1.20 NE555 0.22 6520 3.00 4532-20 2.50 INTERFACE 8271 P.O.A 2,00 7472 0.45 74L50 0.24 74L5628 2.25 1.00 LC7131 3.50 UA4170 NE556 0.60 1.70 6522 7473 0.45 74LS42 0.50 74L5629 1.25 6553 LC7137 3.50 UC548014 3.0 ICs 2.4570MHZISI NE564 4.00 4.00 6522A 4816AP/3 2.00 FD1771 20.00 7474 0.50 74L53 1.50 74LS640 2.00 4555 0.313 LF347 1.20 ULN20014 5.0 150 74ALS SERIES NE565 1.20 0.75 6532 4.80 5101/5501 4.00 AD7581 15.00 F01791 20.00 2.5MHz 2.50 7475 0.60 74LS48 0.90 74LS640-13.00 4556 0.50 LF351 0.60 1.50 ULN2002A 0.75 NE566 6551A 6.00 551//5111 4.00 ADC0808 11.90 FD1793 20.00 2.662MHz 1.75 7476 0.45 74LS49 1.00 74LS641 1.50 4557 2.0 LF353 0.90 ULN203A 0.75 74ALSOO 0.45 NE567 1.25 5516 6.00 A0561 J 20.00 FD1797 22.00 3.276MHz 1.50 7480 0.65 74LS51 0.24 74L5642 150 4560 1.40 LF355 0.90 0LN20040 0.75 74ALS02 0.45 NE570 4.00 6821 1.50 5517AP 6.00 AM25S10 3.50 3.5795MHz 1.00 7481 1.80 74LS54 0.24 74LS642-1 3.00 4566 1.40 LF356N 1.10 ULN20682.90 74AL5040.50 NE571 3.00 68B21 2.50 AM25LS25213.50 WD169115.00 4.00MHz 1.50 7483A 1.05 74L555 0.24 74L5643 2.50 4568 2.4° LF357 1.00 ULN2802 1.90 74ALS08 0.50 NE592 0.90 6829 12.50 6116P-3 3.50 AM25LS253B3S0 WD214312.00 4.194MHz 2.00 7484A 1.25 74LS73A 0.30 741.S643-1 3.00 4569 1.70 LF398 4.00 74ALS10 0.45 4572 NE5532P 1.50 6840 3.75 6118-1-3 3.50 AL126LS31 1.20 W02793 27.00 4.43A4HZ 1.00 0.45 ULN2804 1.90 74ALS20 0.45 6.00 6264-1212.00 AM26LS32 1.20 WD2797 27.00 4.9152MMZ 2.50 7486 0.42 74L575Á 0.45 74LS645 2.00 4583 0.90 LM301A 0.30 UPC575 2.75 6880 74ALS320.45 4584 NE5534P 120 6850 1.60 62p4P-157.0 AA1791ODC25.00 5.00MHz1.0 7489 2.10 74LS76A0.38 74LS845-14.00 0.0 LM307 0.45 NE5534AP1.50 UPC592H 2.00 74AL5740.70 6880 2.50 6261LP-153:40 DAC80CB1-V 5.068MHz 1.75 7490A 0.55 74L578 0.42 74L5668 0.90 4585 0.60 LM308CN 0.75 UPC1158H 3.00 74ALS130 1.50 OP-07EP3.0 6852 2.50 28.00 6.00MHZ 1.40 7491 0.70 74LS83A 0.70 74LS669 0.90 4724 1.50 LM310 2.25 UPCI185H 74ALS139 1.50 PLL02A 5.00 5.00 6856 6514-45 4.00 DM8131 6.00 CHARACTER 6.144MHZ1.40 7492A 0.70 74LS85 0.75 74L56701.70 14411 7.50 LM311 XR210 6.0 74ALS244 4.00 0.60 RC4136 0.55 4.00 68854 8.00 6810 1.80 GENERATORS 7493A 0.55 74L586 0.35 74LS682 2.50 14412 7.50 053304 3.50 7.00MHz 1.50 74ALS245 4.75 LM318 1.0 RC4151 2.00 XR2206 4.50 745189 1.80 DS3691 7494 1.10 74L590 14416 3.00 6875 5.00 3.50 7.16MHz 1.75 0.48 74LS683 3.00 74ALS573 2.0 LM319 1.80 RC4195 1.50 XR2207 3.75 745289 2.25 R032573UC 7.0 7495A 0.60 74LS91 0.90 74L5684 14419 2.60 058830 1.40 8.00MHz 130 150 74ALS574 4.50 LM324 0.45 RC4558 0.55 XR2211 5.75 8154 R032513LC 7.00 7496 74L592 14490 4.20 8.50 D58831 1.50 8.8871402 1.75 0.0 0.35 74L5687 3.50 74ALS580 LM334Z 1.15 55666 2.20 XR2216 6.75 93415 6.00 7497 2.60 14495 8155 3.0 058832 1.50 IO.00MHz 1.75 2.10 74LS93 0.54 74L5688 3:0 4.50 LM335Z 1.30 550240 9.00 XR2240 1.20 93L422 74100 145000 6.50 8156 3.0 7.50 DS8833 2.25 IO.0MHz 2.0 1.90 74LS95B 0.75 74LS783 21.00 LM336 1.60 SAA1900 16.00 ZN404 1.00 93425 2.00 6.00 D68836 1.0 10.70MHz 1.50 74107 0.50 74LS96 0.90 4000 SERIES 14599 LM339 0.40 SFF963134 8.00 ZN414 0.80 8205 2.25 ' D58838 2.25 11.00MHz 3.00 74109 0.75 74L5107 0.40 22100 3.50 LM348 0.0 ZN419P 1.75 REAL SL490 3.00 0212 2.00 07002 6.00 12.00MHz 1.0 74110 0.75 74L5109 0.40 000 0.20 22101 7.00 LM358P 0.50 ZN423E 1.30 CLLOCINE SN7013N 3.00 ' 8218 1.60 MC1488 0.60 14.0014Hz 1.75 74111 0.55 74L5112 0.45 4001 0.24 22102 7.00 LM377 3.00 SN76023N ZN424E 1.30 PROM. 745 3.00 8224 P.O.A MC1489 0.0 14.31MHZ 1.0 74116 1.70 74L5113 0.45 SERIES 4002 0.25 40014 0.48 LM30N-8 1.0 ZN425E83.50 SN76033N 3.00 8226 4.25 MC3646 2.50 14.756MHz 2.0 74118 1.10 74LS114 0.45 006 0.70 40085 1.20 LM30N 1.50 ZN426E83.00 28522 4.00 SN76115N 2.15 8228 5.0 MC3459 4.50 15.00MHZ 2.00 74119 1.70 74LS122 0.70 74500 0.50 4007 0.25 0097 °68 LM381AN1.70 SN764894.00 ZN427E86.00 24570 2.502. 8243 MCS3470 4.75 16.00MHz 2.00 74120 1.00 74LS123 0.80 74502 0.50 4008 0.60 00913 0.40 LM383 3.25 ZN428E84.50 2.0 18S030 2.00 50764954.00 8250 MC3480 6.50 17.734MHZ 1.0 74121 0.55 74LS125 0.50 74504 0.50 4009 0,45 40100 1.50 LM384 2.20 ZN429E82.25 8.0 18SA030 2.00 SN76601.20 MC3486 2.25 18.0014Hz 1.0 74122 0.70 74LS126 0.50 74505 0.50 4010 0.60 40101 1.25 LM386N-1 1.00 2N447E 9.00 74S188 1.80 SP0256AL27.00 8251A 3.25 MC3487 2.25 18.432MHz 1.0 74123 0.0 74L5132 0.65 74508 0.50 4011 0.24 40102 1.30 LM387 2.70 SP8515 7.50 ZN449E 3.00 745287 2.25 TELETEX7 8253C-5 3.0 74S268 1,6p MC4024 5.50 19.OB0MHz 1.0 74125 0.65 74L5133 0.55 74510 0.50 012 0.25 40103 2.00 LM389 1.89 TA7120 1.20 ZN40E 7.50 DECODER 8255AC-5 3.20 MC4044 5.50 20.000MHz 1.0 74126 0.55 74LS138 0.45 74511 0.75 4013 0.36 0104 1.20 LM391 1.80 TA7130 1.40 Z5459CP 3.00 74S387 2.25 8256 18.00 MC14411 9.00 SAA0208.00 24.000AIHz 1.75 74128 0.55 74LS138 0.55 74520 0.50 4014 0.60 0105 1.50 LM392N 1.10 ZN1034E 2.00 82523 1.50 TA7204 1.50 8257C-5 SI.00 MC744127.0 SAA0307.00 18.000MHZ1.75 74132 0.75 74L5139 0.55 74522 0.50 4015 0.70 40106 0.46 LM393 0.85 TA7205 0.90 ZNA10406.0 825123 1.50 82S129 75107 0.90 S505011 16.00 118MHZ 2.5 74136 0.70 74LS145 0.95 74530 0.50 016 0.36 0107 0.55 LM396CH 4.00 TA7222 1.50 ZNA134J 23.00 ' 1.75 8259C-5 4.00 - 75108 0.90 SAA009.00 , P001000 12.00 74141 0.90 74LS147 1.75 74532 0.0 4017 0.55 40108 3.20 LM709 0.35 ZNA234E9.0 TA7310 1.50 8271 75109 1.20 74142 2.0 74LS10 1.40 76537 0.60 4018 40109 0.80 P.O.A 0.60 8275 29.00 75110 590 74143 1.30 74L5151 0.65 74S38 0.60 0.60 40110 2.25 VOLTAGE REGULATORS 019 8279C-5 4.80 75112 1.60 74144 2.70 7415152 2.00 71540 0.50 4020 0.80 0114 2.25 EE PROM 8282 4.00 75113 1.20 Please note: 74145 1.10 74L5153 0.85 74551 0.60 4021 0.60 40147 1A FIXED VOLTAGE PLASTIC TO220 ' ' 75114 1.40 74147 1.70 74L5154 1.60 74564 0.45 4022 63 1.00 All prices are subject to 0.70 8284 4.80 2816-3015.00 75115 1.40 74148 1.40 74LS155 0.65 74574 0.70 4023 0.30 40173 1.20 +VE -VE notice 8287 3.00 2K+8 30.00 75121 1.40 change without 74150 1.75 74L5158 0.65 74585 3.00 4024 0.48 0176 1.00 5V 7805 0.45 7905 0.50 82880 9.50 9306 2`i6D 75122 1.40 74151A 0.70 74L5157 0.50 74586 1.00 4025 0.24 40175 1.00 6V 7806 0.50 7906 0.50 Only current prime grade 8755A 16.00 (16X16) 4.50- i 75150P 1.20 74153 0.80 74LS158 0.65 745112 1.50 026 0.90 40192 1.00 6V 7808 0.50 7908 0.0 Components stocked. 74154 1.40 74L51604 0.65 745113 1.20 027 0.40 4°193 1.00 12V 7812 0.45 7912 0.50 OTHERS 74155 0.80 74141810 0.75 745114 1.20 4028 0.60 40194 1.00 15V 7815 0.50 7915 0.15 LEDs 40244 1.50 74156 0.90 74LS1624 0.75 745124 3.00 4029 0.75 18V 7818 0.50 7918 0.50 2N5777 0.0 4024.5 1.50 74157 0.80 74LS163A 0.75 745132 1.00 030 0.35 24V 7824 0.50 7924 0.50 BPX25 1.80 0125" 02" 74159 40257 1.80 We also stock a wide 1.75 74LS164 0.75 745133 0.0 4031 1.25 IA FIXED VOLTAGE PLASTIC 7092 BPW21 280 RED TIL2090.12 TIL220 0.15 74160 1.10 74LS1654 1.10 745138 1.80 40373 1.80 4032 1.00 5V 78105 0.30 5V 79L05 0.45 OCP71 1.0 GRN TIL2110.16 111.222 0.18 range of: 74181 0.80 74L51884 745139 0374 1.80 1.50 1.80 4033 1.25 6V 78L06 0.30 12V79L120.0 0RP12 1.20 YEL11L2120.20 T1L226 0.22 74162 1.10 74LS168 1.30 1.00 BOC95 0.75 Transistors, 74510 4034 2.50 8V 78L08 0.30 15V 79L15 0.50 ORP60 1.20 Rect LEDs 74163 1.10 74L5169 1.00 745151 80C97 0.76 1.50 4035 0.70 12V 78L12 0.30 ORP61 1.20 (R/G/Y) 0.30 COUNTERS Diodes.Triacs Plastic, 74164 1.20 74LS170 1.40 745153 1.50 038 2.50 8°C98 075 CXO (Bi colour 15V 78L15 0.30 - ' SFH2O5 1.00 74185 1.10 71LS173A 1.00 745157 2.00 6037 1.10 T1L32 0.55 1.00 74C925 6.50 Bridge Rectifiers, 74166 1.40 74LS174 0.75 745158 2.00 038 1.00 TIL7B 10 LED 74C926 6.50 OTHER REGULATORS t 0.55 Thyristors and 74167 4.00 74LS175 0.75 745163 3.00 040 0.60 TIL31B 1.20 BarGraph: 74928 6.50 74170 2.00 74L5181 2.00 745169 5.50 4041 0.55 FIXED REGULATORS TIL81 1.20 -Reo 2.25_ .7216B 22.00 ZenOrS. 74172 4.20 74LS183 1.90 745174 3.00 4042 0.50 LM309K IA 5V 140 'TIL100 0.75 Green 2.25 1ZN1040 6.70 74173 1.40 74LS190 0.75 745175 3.20 4043 0.0 LM323K 3A 5V 350 Please phone for 74174 1.10 74L5191 0.75 745188 1.0 4044 0.60 78H05KC 5A 5V 540 74175 1.05 74L5192 0.80 745189 1.80 4045 1.00 78H12 5A 12V 640 DISPLAYS MAN68102.00 LM3914 3.50 details. N5858815.70 74176 1.00 74LS1944 0.75 745194 3.00 046 0.60 78P05 10A 5V LM3915 3.50 900 TIL311 6.50 74178 1.50 74L5195A 0.75 745195 3.00 4047 0.60 LM3918 3.50 VARIABLE REGULATORS TIL729 1.00 74179 1.50 74L5196 0.0 745196 3.50 048 0.55 UDN6118 3.20 LM305AH 250 FND357 1.00 TIL7300 1.00 74180 1.00 74LS197 0.60 745200 4.50 4049 0.36 UDN61843.20 OPTO-ISOLATORS LM3177 TO-220 1 50 FN)00/111.730 74181. 3.40 74L5221 0.90 745201 3.20 050 0.35 MAN8910 1.50 ULN20030.90 LM317K TO3 240 1.00 MAN8940 74182 1.40 74LS240 0.80 74S225 5.20 4051 0.65 2.50 ULN20040.90 LM337T 2 25 F0007/71729 1LD74 1.30 rIL111 0.70 74184 1.80 74L5241 0.80 74520 4.00 4052 0.60 ULN20682.90 LM30T 10A+VAR 400 1.00 DISPLAY IL074 2.20 TIL112 0.70 74185A 1.80 74L5242 0.90 745241 4.00 4053 0.60 ULN2021.90 LM323K 10A+VAR 15.00 MAN71/DL707 DRIVERS MCT26 1.00 TIL113 0.70 74190 1.30 74LS243 0.90 74S244 4.50 4054 0.80 ULN20831.0 LM723N 00 1.00 MCS2400 1.60 T1L118 0.701 1 74191 1.30 74LS244 0.80 745251 2.50 4055 0.80 ULN2041.90 78HHO5KC 5A 5V 5 75 MAN3640 1.75 9388 M0C3020 1.0 SN137 360 74192 1.10 74LS245 1.10 745257 2.50 4056 0.85 4.50 75491 0.70 78HGKC 5A+VAR MAN4640 2.00 SN139 1.751 74193 1.15 74L5247 1.10 74S258 650 9370 4.50 75492 0.70 2.50 4060 0.70 78GUIC 1A+VAR 74194 1.10 74LS248 745260 225 1.10 1.00 4063 0.85 79HGKC 5A-VAR 675 74195 0.80 74L5249 1.10 745261 3.00 4066 0.40 LOW PROFILE SOCKETS BY TI WIRE WRAP SOCKETS BY TI 79GUIC 1A-VAR 2 50 74196 1.30 74LS251 0.75 745283 2.70 4067 2.30 74197 1.10 74LS253 0.75 745287 2.25 4068 0.25 SWITCHING REGULATIONS .Bpin 9p 185in 18p 24pn 24p Spin 25p 18pin SOp 24pin 70p 74198 2.20 74LS256 0.90 745288 2.00 4069 0.24 ICL760 2 50 hdpin lOp 20Pin 18p 28p n 26p 14pin 35p 20pin 60p 28pin 60p 74199 2.20 74LS2457A0.70 74S289 2.25 070 0.24 SG3524 3pp 16Pin 11p 22pin 20p 40pin 30p 16PIn 40p 22pin 65p Opin 100p 74221 1.10 74LS258A 0.70 745299 4.50 4071 0.24 TL494 3 00 74251 1.00 74LS259 1.20 745373 4.00 4072 0.24 TL497 300 TURNED PIN BPin 25p 16pin 35p 24pin 45p 2Bpin 95p 74259 1.50 74L320 0.75 745374 4.00 4073 0.24 78540 2 50 In 1 LOW PROFILE SOTS. 14pi 30 p 1pin8 40p 24pin 55p Opin 90p 74265 0.80 74L5266 0.60 745387 2.25 4075 0.24 RC6195 50

PLEASE ADD 50p p&p & 15% VAT TE uI NOM ATIC LTl) (Export: so VAT, p&p at Cost) %1 all. ORDERS TO: 17 BURNLEY ROAD, LONDON NWIO lED Orders from Govetnment Depts. & Colleges etc. welcome. SHOPS AT: 17 BURNLEY ROAD. LONQON NW10 =CZ= Detailed Price List on request. VISA Tel: 01 -723 0233 4 lines. Telex: 922800 Stock Hems are normally by return post. of Il 305 EDGWARE ROAD. LONDON W2 Nlinintnm Telephone Order £5

ELECTRONICS & WIRELESS WORLD MAY 1986 71

www.americanradiohistory.com Hitachi Oscilloscopes the highest quality from £299 1 the most competitive prices +VAT

Hitachi Oscilloscopes provide the quality and performance that you'd expect from such a famous name, with a newly- extended 14 model range that represents the best value for money available anywhere. V- 212/222 20MHz Dual Trace V-650 60MHz Dual Timebase V -223 20MHz Sweep Delay V-1050 100MHz Quad Trace (illustrated) V-1070 100MHz Four Channel V -209 20MHz Mini- Portable V-I100 100MHz DMM /Counter V -422 40MHz Dual Trace V- I 34 10MHz Tube Storage V -423 40MHz Sweep Delay VC-6015 10MHz Digital Storage V -509 50MHz Mini -Portable VC-6041 40MHz Digital Storage Prices start at £299 plus vat (20MHz dual trace) including a 2yr. warranty. We hold the range in stock for immediate delivery. For colour brochure giving specifications and prices ring (0480) 63570 Thurlby Electronics Ltd, New Road, St. Ives, Cambs. PE17 4BG CIRCLE 57 FOR FURTHER DETAILS. Add 8 channels to your 'scope New Thurlby 0M358 multiplexer £179 +vat ;///////////////i. The Thurlby 0M358 -gives any oscilloscope an 8 channel display. Observing many waveforms simultaneously can be essential when analysing sophisticated equipment. Application areas include microprocessor based products, data transmission systems, A to D converters, frequency synthesizers etc. The OM358 is ideal for digital equipment (it can often solve problems that would otherwise need a fast logic analyser) but, unlike dedicated logic test instruments, it is equally suited to analogue waveforms. The 0M358 has a bandwidth of 35MHz and 307o calibration accuracy. Each 8 input has an impedance of 1 f1 - 20pF and accepts signals up to ± 6V. An channel, 4 channel, or single channel display can be selected with triggering

from any channel . Colour data sheet with full specifications available. Thurlby Electronics Ltd I III Thurlby /\ New Road , St.lves , Cambs. designed and built in Britain PE17 4BG Tel: (0480) 63570 CIRCLE 58 FOR FURTHER DETAILS. The world's most advanced low -cost bench multimeter! Thurlby 1905a £349+ VAT A complete high performance bench DMM 51/2 digits; 0.015% acc; 1 ).1V, 1mi2 , 1nA. Full ac and current functions as standard A sophisticated computing and logging DMM Linear scaling with offset; null /relative Percentage deviation; running average dBV, dBm general logarithmic calculations Limits comparison; min and max storage 100 reading timed data logging RS232 and IEEE -488 interface options Thurlby Electronics Ltd New Road, St.lves, Cambs. PE174BG III Thurlby) 42 Tel: (0480) 63570 designed and built in Britain CIRCLE 59 FOR FURTHER DETAILS. Now Thurlby makes logic analysis affordable ! from the new Thurlby LA -160 £395 +vat

16 channels, expands to 32 2K word acquisition memory Clock rates up to 20MHz Non -volatile reference memory State and timing displays Search and compare facilities Selectable display formats Hard -copy data print -out An oscilloscope and logic probe are not enough to unravel the complexities of today's electronic equipment. A logic analyser is as essential for observing digital signals as an oscilloscope is for observing analogue signals, and now Thurlby puts one within every engineer's reach. Contact us now and get the full technical data. Thurlby Electronics Ltd III Thurlby) New Road, St.lves, Huntingdon, designed and built in Britain Cambs. PE17 4BG, England. Tel: (0480) 63570 CIRCLE 60 FOR FURTHER DETAILS. www.americanradiohistory.com AFFORDABLE ACCURACY Quality Multimeters from THE Cirkit PEAK... A comprehensive range of Analogue and (Pushbutton or Rotary Switched) Digital Models OF PERFECTION Lammomadet1remmr.rq . Designed and manufactured r in West Germany by Hameg, w; ANALOGUE DIGITAL one of the World's leading a.... HM -102BZ - IOADC Range. 20kO VDC. HC -7030 Buzzer, Battery Test Scale _.__._.___... S1250 0.1 %Accuracy Standard Model ...... _53950 oscilloscope manufacturers - 19 measuring ranges HC -6010 HM -102R - Low end voltage & current 0.254 Accuracy. Standard Model 533.50 a complete range of high

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CIRCLE 67 FOR FURTHER DETAILS. HM208 £1300(£1550 WitnIEEE) 20 MHz Digital Storage

Outstanding 20 MHz max. sampling rate . 4 x 1k Memory . 8bit

vert. resolution . Digital Timebase from 50 s /div. to 10us/div. .

Stores X Y-Operation . Single /Refresh /Roll Mode . Analogue Output . IEEE -Bus optional . Sensitivity lmV /div. - 20V /div. HM605 £ 515 60 MHz Dual Trace O Sensitivity 5 mV /div. at 60 MHz, lmV at 5 MHz . Automatic

peak -value or normal triggering to 80 MHz . Delay Line Variable C/u Sweep Delay . Timebase from 2.5s /div. to max. 5ns /div.. Unique fast -risetime 1 kHz /1 MHz calibrator . Y- Output . High -resolution 15 kV CRT HM204 £ 365 v748 20 MHz Dual Trace Sensitivity 5mV - 20V /div., 1 mV at 5 MHz . Timebase from Amateur Radio & Electronics 1.25s/div. to max. 10ns /div. DELAY LINE . Variable sweep delay . Single sweep . Automatic peak -value trigger to 50 MHz . Y -Output . Hobby Fair Z- Modulation . Overscan indicator To be held at Wembley Conference Centre, HM203 £270 Saturday 5th & Sunday 6th July 1986 20 MHz Dual Trace Western - The first Two Day Fair to be held in the South of Europe's best selling 20 MHz Scope! Sensitivity ( 2mV/d iv. .Trigger bandwidth 40 MHz . Timebase from 0.2s /div. England. A major new event in the Amateur to max. 2Ons /d iv. . X -Y . Component Tester Radio Calender. 2 Years Warranty Prices U.K. list ex.VAT 7 Over 200 retail & manufacturers stands - plus lots more. 11-10=1 11 FOR THOSE WHO 7 See future publications for more details. COMPARE 74 - 78 Collingdon St. Luton, Beds, LU1 1 RX The organisers are: Amateur Radio Promotions, Tel: (0582) 413174 Telex: 825484 Woodthorpe House, Clapgate Lane, Birmingham CIRCLE 26 FOR FURTHER DETAILS. B32 3BU - Telephone: 021 -421 -5516. CIRCLE 76 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MAY 1986 73

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DISPLAYED APPOINTMENTS VACANT: £21 per single col. centimetre (min. 3cm). Advertisements LINE advertisements (run on): £4.50 per line, minimum £i:O (prepayable). BOX NUMBERS: £10 extra.' (Replies should be addressed to the Box Number in the to 12 noon accepted up advertisement, c/o Quadrant House, The Quadrant. Sutton, Surrey SM2 4AS). May 7th for June PHONE: SUSAN PLATTS, 01 661 3033 (DIRECT LINE) issue 1 Cheques and Postal Orders payable toBUSINESSPRESSINTERNATIONAL LTD. and crossed.

THE BESTAPPROACH

£7,000- £30,000 + CAR * Where does your interest lie: Graphics; CAD; Robotics; Simulation; Image and Signal Processing; Medical; Automation; Avionics; Acoustics; Weapons; Comms; Radar; Opto and Laser? * Experienced in: VLSI; Microprocessor Hardware or Software; Digital and Analogue circuitry; RF and Microwave techniques? * There are hundreds of opportunities in: Design; Test; Sales and Service for Engineers and Managers * For free professional guidance: Call: 0638 742244 (till 8pm most evenings) or write (no stamp needed) to

ELECTRONIC COMPUTER AND MANAGEMENT APPOINTMENTS LIMITED (19261 FREEPOST. The Maltings, Burwell, Cambridge, CB5 8BR.

PIONEER TECHNICAL LIAISON ENGINEER BRITISH GEOLOGICAL SURVEY WITH A DIFFERENCE ELECTRONICS ENGINEER The Survey has a vacancy for an Electronics Engineer in its Marine Operations c £11,000 Research Programme. The successful candidate will work in a small electronic engineering section of four people, responsible for the development, modification The successful candidate will join a small engineering team, and maintenance of electronic equipment in support of the Survey's marine survey responsible for the technical support of our full range of Hi work. The equipment uses analogue and digital techniques in systems of both commercial and in -house design. The work will normally involve participation of Fi, Car Audio and Video products. offshore and inshore surveys for up to 70 days each year, for which there are He /she will be responsible for the technical evaluation of generous allowances in addition to salary. A wide variety of equipment is used on these surveys including specialist products which includes investigating and resolving product navigation and data logging systems and a range of shipborne and towed problems, answering dealers' and consumers' geophysical sensors. Prior experience of geophysical equipment would be useful enquiries and giving advice but not essential. The work requires a blend of sound theoretical and practical correspondence, telephone ability. to and after sales service. relating Pioneer products The appointment will be at Scientific Officer or Higher Scientific Officer level. The applicant for this very important and interesting position Qualifications will have at least five years experience in repairing domestic Degree or equivalent in electronics. For appointment as Higher Scientific Officer, must have at least 2 years relevant postgraduate experience. audio and video products and should ideally be quqlified to candidates Salary City and Guilds in radio and television and /or HNC in Depending on qualifications and experience, salaries will be within the following electronics or equivalent, and must have experience in scales, which are currently under review: - dealing with technical correspondence. Scientific Officer £6190 -£8561 High Scientific Officer £7788-E10541 Benefits include four weeks annual holiday, rising to five Starting salaries may be above the minimum. Occupational Pension Scheme. weeks, contributing pension scheme and private health Location cover. The post will be located at Edinburgh, but staff appointed to the Survey are liable to in any part of the United Kingdom or overseas. application form, please serve For further information or an For further details and an application form, write to Establishments (Recruitment) contact:- Section, British Geological Survey, Keyworth, Nottingham, NG12 5GG. Closing Mrs. C.A. Burridge, date for receipt of completed application form is 30 April 1986. Please quote reference: HS /C4 /ED /1 Pioneer High Fidelity (GB) Limited, (2281 1 -6 Field Way, Greenford, Middlesex.

Telephone: 01 -575 5757 ( 2251

ELECTRONICS & WIRELESS WORLD MAY 1986

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FREE OFFER! ENGINEERING Clip this advert for tree career guidance and help in finding OPPORTUNITIES your next position. We have a wide selection of the best appointments in Digital, Analogue, RI; Microwave, Micro- processor, Computer, Data Cumins and Medical NATIONWIDE Electronics, and we're here to serve your interests. Call us now for posts in Design, "list, Sales or Field Service, Edinburgh (031) 226 5381 ,/ at all levels from £6,000 - £18,000. Leeds (0532) 580510 I ED /NBUROM Manchester (061) 832 5856 1 f Birmingham (021) 6431994 ®`Technomar&Erlgineenng & Technical Recruitment Leicester (0533) 544193 *LEEDS "ESTER Milton ° 11 Westboume Grove, London W2. Tel: 01- 229 9239 Keynes (0908) 666872 e" "` 1. (1935) p, Bishop's Stortford (0279) 506464 BIRMINGHAM. U 4 London (01) LEICESTER 637 0781 MILTON xEYNES Bristol 211035 BISHOP'SSrvwrEOR "' (0272) `, jt/ONOON: RIVERSIDE HEALTH AUTHORITY STOLS BRACKNELL. Bracknell (0344) 481808 CRA ET.ST MAIDSTONE

' . WESTMINSTER HEALTH AUTHORITY Maidstone (0622) 687171 tt DEPARTMENT OF PHYSICS Crawley (0293) 514071 Chief Electronics Technician is required to take charge of a small but active electronics workshop. You should have advanced experience in electronics, microwave techniques, medical Salaries £8,000 to £30,000 p.a. instrumentalism and computer technology. As the UK's leading specialist sales and technical recruitment consult- Informal 1 enquiries to: Dr JP Nicholson on 01 -828 981 ext 2505. ancy, we provide a FREE service to engineers seeking a career move. Salary: £9157 - £11,154 (inclusive of London Weighting). If you have experience in Microprocessors (HAN or S/W), Digital or Application forms and job descriptions available from the Personnel Analogue technologies, ideally with a recognised qualification, we have Department, Queen Mary Nurses Home, 20 Page Street, London hundreds of vacancies throughout the UK in R & D, Design, Manufact- SW 1. Tel: 01 -400 0296 (24 hour service). Please quote reference uring, Test, Service and Sales. number A/2191 . Call your nearest branch for more information or send a Closing date: 30 April, 1986. (224) comprehensive C.V. (no stamp required) to:-

aA Division of ATA Selection and Manaaemen Services Ltd Solid State Logic FREEPOST, Bishop's Stortford, Herts. CM23 2BR. 115 Oxford England

The independent local radio station for South Wales has a vacancy for an Engineer, Grade ILR 2, based in Cardiff. TECHNICAL DOCUMENTATION The successful applicant will enjoy a wide variety of work including project design and development, technical maintenance and Studio and Outside MANAGER Broadcast operations. Solid State Logic manufactures an advanced Applicants should be qualified to Degree /HND level in Electronics and have and comprehensive range of audio mixing experience in broadcasting or a related field. A clean driving licence is essential. consoles and studio computers for the Salary is in accordance with current ACTT rates. Apply in writing, including a recording and broadcast industries. full C.V. to:- We require a Technical Documentation DAVE COCKRAM, CHIEF ENGINEER, Manager to coordinate the production of the RED ROSE RADIO PLC, complex technical manuals for our complete P.O. BOX 301, range of products. The successful applicant will ST. PAULS SQUARE, PRESTON. PRI LYE be responsible for all technical writing and the i145) efficient use of computer and drawing office resources, including CAD. Applicants should have proven ability as a clear and concise technical writer, and be able to CAPITAL APPOINTMENTS LTD work to tight timescales on your own initiative. THE UK's No. 1 ELECTRONICS AGENCY You will be expected to gain a detailed If you have HNC/TEC or higher qualifications and are understanding of the present product and to looking for a job in design, test, customer service, technical possess the necessary energy and imagination sales or similar fields: to motivate the small team for which you would Telephone now for our free jobs list be responsible. We have vacancies In all areas of the UK This is a demanding but rewarding post, as part Salaries to £15,000 pa of a friendly Research and Development team based in rural Oxfordshire. 01 808 3050 Please request an application form from: (24hours) Solid State Logic, Stonesfield, Oxford OX7 CAPITAL APPOINTMENTS LTD 2PQ or telephone 0993 89 8282. 76 WILLOUGHBY LANE, LONDON N17OSF 219 9,

ELECTRONICS & WIRELESS WORLD MAY 1986 75

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THE START OF Nationwide Building Society SOMETHING has vacancies for two NEW TELECOMMUNICATIONS ENGINEERS at its Administrative and Computer Centre at Princes Street, College and planning a career in modern If you are leaving Swindon communications or if your present job lacks interest and challenge why not join us in GCHQ? The computer system, a Sperry 1100/92, supports a network of over We are recruiting 2000 terminals in the Society's branch offices. The successful applicant will join a small team responsible for the maintenance and development of the Society's telecommunications RADIO OFFICERS networks. He or she will be involved in a range of teleprocessing ac- who are after initial training will become members of an tivities, including the identification and isolation of faults and the organisation that is in the forefront of communications general maintenance of microprocessor and communications equip- technology. Government Communications Headquarters ment. The position is seen as a career opportunity and necessary can offer you a satisfying and rewarding career in the wide training will be provided. field of communications. Training involves a 32 week course (38 weeks if you come straight from Nautical Experience of at least one of the following items is required; College) which will fit you for appointment to RADIO Switching /Statistical Multiplexers OFFICER. Network Control Systems Not only will you find the work as an R 0 extremely Microprocessors interesting but there are also good prospects for Modems promotion opportunities for overseas travel and a good British Telecom lines and equipment salary. Add to this the security of working for an important Candidates should preferably hold an HNC /HND or Higher TEC Cer- Government Department and you could really have the tificate/Diploma in Electrical /Electronic Engineering. start of something new. Commencing salary in the range £8,115 to £8,934 per annum subject The basic requirement for the job is 2 years radio operating to review on 1 April. The Society has its own Superannuation and experience or hold a PMG, MPT or MRGC or be about to Sickness Schemes. Fringe benefits include four weeks one days an- obtain a MRGC. Registered disabled people are welcome to nual holiday entitlement, staff restaurant and, after a qualifying apply. period of three years service, concessionary mortgage facilities. Salaries start at £4,988 at age 19 to £6,028 at age 25 and Please telephone for an application form, 01 -242 8822, Ext 2582. at 19 to £8,915 at 25 over during training and then £6,832 R N Wharton, Recruitment Manager and over as a Radio Officer. Increments then follow Nationwide Building Society annually to £12,328 inclusive of shift and weekend working New Oxford House, High Holborn allowances. London WC1V 6PW phone 0242 32912/3 application form Nationwide Building Society. The Recruitment Office A/1108 an Equal Opportunity Employer. Priors Road 221 CHELTENHAM (2806) Glos GL52 5AJ

CLIVEDEN SCOTTISH OFFICE 1. SERVICE ENGINEER Repair and install laser DIRECTORATE OF TELECOMMUNICATIONS printing equipment. WIRELESS TECHNICIAN £12,000 plus Car. N.W. £9,317 (currently under review) University of Wales London. £6,810 - MSc /Diploma course in 2. SYSTEMS ENGINEER Applications are invited for 1 post of Wireless Technician in the To provide technical support on a Central Services Department of the Scottish Office. The post is Electronics wide range of mini and micro based in Edinburgh. (Digital Systems, systems. f 13.,000 + Car. Berks. Candidates must have a sound theoretical and practical knowledge Control, 3. TEST ENGINEER of Radio Communications Systems both fixed and mobile, in the Communications, Repair and calibrate a wide range frequency range HF to 2 GHz. They must also be able to use test Medical Electronics) of pocket and radio pagers. equipment and simple machine tools. A sound basic knowledge of £10,000. Hants. digital techniques would be an advantage. They should have a MEng Course in 4. FIELD SERVICE and should hold an Repair of mini and micro based minimum of 3 years appropriate experience Systems Engineering texts processing equipment. Ordinary National Certificate in Electronic or Electrical Engineering Robotics in an appropriate (Automation, £10,000 + Car. Berks. or a City and Guilds of London Institute Certificate Information 5. TEST ENGINEERS subject or a qualification or higher or equivalent standard. Some and RF /VHF /UHF radio telecoms assistance may be given with re- location expenses. Systems) equipment. £10,000. Berks. A valid UK driving licence is essential. Applications are invited for 6. SERVICE ENGINEER For full details and an application form (to be returned by 9 May places on the above full - To provide support on discs and 1986) write to Scottish Office Personnel Division, Room 110, 16 time, one -year courses tape drives. c. £13,000 + Car. EH1 3DN (or telephone 031 556 8400 Berks. Waterloo Place, Edinburgh commencing in October Ext 4317 or 5028). Please quote ref PM(PTS)1 /3/86. 1986. The Civil Service is an equal opportunity employer. (229) Phone or write: Further details and Roger Howard C.Eng. M.I.E.E. M.I.E.R.E. application forms (returnable as soon as CLIVEDEN RECRUITMENT possible) may be obtained 1AR 92 Broadway, Bracknell, Berkshire 11612 the Assistant Tel: 0344 489089 from Registrar, UWIST, PO Box 68, Cardiff CFI 3XA. 226

MAY 1986 76 ELECTRONICS & WIRELESS WORLD

www.americanradiohistory.com Appointments

tele soníc ELECTRICALIMECHANICAL ENGINEER ELECTRONIC TECHNICIAN Telesonic Marine Ltd., A rapidly expanding Company, have the INTERESTING WORK following vacancies required pronto by video REPAIRING, MANUFACTURING manufacturing company AND DEVELOPING ELECTRONIC A BENCH SERVICE ENGINEER. The candidate will be FLASH EQUIPMENT FOR A in situated near Ringwood LEADING PHOTOGRAPHIC experienced the service of Yacht Marine Electronic DISTRIBUTOR IN CENTRAL LONDON. Equipment, have in Hampshire or good general Marine Electronics Applicants should have a background. You should live in, or close to London. The ability Responsible person in knowledge of basic electronics to to work unsupervised is essential. Salary £6000 to £8000 neg. small team. ONC Level. City & Guilds standard but experience in this field is not A TRAINEE INSTALLATION ENGINEER. The candidate will Salary dependent on essential. A driving licence would be have a good general knowledge of Marine Electronics, and be experience. an advantage. Salary negotiable able to use their hands. The candidate will be required to work Telephone Tony Beveridge on Tel 0202 01.833 4737 for an Interview. overseas, so a passport is essential. You should also hold a 825253 (204) valid UK driving licence. Starting salary £6000 + OIT and for an application form. overseas working neg. 216

Reply to Mr. Spackman on 01 8374106 (201)

Classified

ARTICLES FOR SALE

"GRAND CLEARANCE SALE, on Saturday May 24th, 10 a.m. to 5 p.m. at: Unit 2, The Maltings, 135 Ditton Walk, Cambridge (near football stadium) Examplefs; M A R T E L L A S E R S Keyboards 88 key with 8748/8048 £4 ea, 2 for £7, 3 for £8. Marconi 801 D £35. TFPM43 /42 transmission level test set £25, TEK 520 vectorscope £195, 1 mW LASER HEAD Crystal calibrator RCA WR99A £25, Micro development systems, TEK 8002 COMPLETE WITH POWER with 8024 intelligent terminal, ices for 8085 and Z80 c/w SW and doc. £850, Zilog Z80 dev. syst. c/w SW and doc. £450, MDS800 Intel less discs £100, SUPPLY KIT £139.00 +VAT. SMS3000 8XS3000 18X300) micro controller dcev. syst £350, TEK 4610 -1 P.P. INCLUDED. photoplotter £25, Versatec V80 Hi res printer/plotter £400, Perkin Elmer laser gauge, offers?, TEK GMA102 and 103 graphics screens new unused £95 ea, MAINS & BATTERY HP7221 B 4 colour digital A3 plotter RS232 + HP1 B I/F £350, TEK61 1 storage screen + terminal two for £75, Linear transducers and readout units various OPERATED POWER from £15, HP5000 A logic analyser £ 100, HP3420 ratiometric voltmeter £80, MODULES AVAILABLE. ESR meter £50, Gauss meter £50, Penrecorders single pen and multi point, Printers, Centronic 705 £75, ASR Teletype £50, DRI 6330 £45, Drum plotter OFFICIAL ORDERS FROM CIL 6000 2 pen 2 speed AO size £250, RRC viewdata plinths £35 ea. Many GOVERNMENT DEPTS more items, power supplies, Components, Subassemblies, PCB's etc. prices from a few pence to pounds. No reasonable offers refused." WELCOME MARTEL LASER CO. LTD. 1 7/19 Whitworth Street West Manchester RERS, M1 5WG TOMANUPE7 H LESALERS United Kingdom BULK BUYERS. ETC. Telephone: 0612 -228 0965 LARGE QUANTITIES OF RADIO. TV AND 222 ELECTRONIC COMPONENTS FOR DISPOSAL SEMICONDUCTORS, all types, INTEGRATED CIRCUITS, TRANSISTORS, DIODES, RECTIFIERS, THYRISTORS, etc. RESISTORS, C /F, M /F, W /W, etc. CAPACITORS, SILVER MICA, POLYSTYRENE, C280, C296, DISC Vacuum pumps: CRT regunning, lasers, FM & MW BROADCAST CERAMICS, PLATE vacuum tools - pen, chuck etc., inductor CERAMICS, etc. encapsulation, microscopy, furnace, EQUIPMENT ELECTROLYTIC CONDENSERS, SPEAKERS, CONNECTING WIRE, CABLES, semiconductors, freeze drying. lost was A special range of high quality SCREENED WIRE, SCREWS, NUTS, CHOKES, TRANSFORMERS, etc. casting, taxidermy, diamonds etc., rotary pump £59, diffusion pump £49. Gas ALL AT KNOCKOUT PRICES Come and pay us a visit transmitters, power amplifiers, - ALADDIN'S CAVE flow- meters £5 -E15. Twin -pem chart TELEPHONE: 445 0749/445 2713 recorder £79. Ultrasonic Detector for stereo encoders, UHF repeater mechanical faults, gas /carbura- links, compressors, antennas. R. HENSON LTD. tion /exhaust /vacuum /pressure leaks etc., 21 Lodge Lane, North Finchley, London, 11.12 £85. Densitometer £25. Micro -spot Powers 10w to 1kw. (5 minutes from (1613) Tally Ho Corner) welding heads £59. Small single /3 -phase Built to high specifications at an converter £35. B. & K. LCR Bridge £35. Low -R Ohmmeter, 5 -range E45. Auto - economic price. Meets IBA & Home charger E.2080 £25. Coating thickness Office specifications. MUST SELL 2 x Ferrograph audio DIGITRON 1751 Thermocouple Gauge £25. Centrifuge £49.500gm analyser ARAI balance (balancing centrifuge tubes etc., Full catalogue available. Wayne Kerr digital Meter Hewlett Packard digital £39. H -P Audio Analyser (individual display store, ADS1 Scopes Gould multimeter 3476A inductance meter harmonics) £69. Double -pulse Generator 053000A telequipment D83, Telonic 122 DLM 307 2xdandridge decade box £49. Schlumberger Compact Cyberscan International, 3 Eastcote 3 +Scopex 456, National VP3830A, drs /abcde digital scale Gravitron Compact -33 Data Logger £50. Vièw, Pinner, Middx HA5 1AT. National Wow /Flutter Meter £65. Meter -Flow auto distortion meter VP772A, 300/3000, counting scale, GEM 120 Tel: 01 -866 3300 '21? Sweep generator VP8820B, Marconi drawing copier, Astra pillar drill 1000 Frequency /DC Converter £25. W_K universal Portable VHF Frequency Standard £45. bridge TF1313A, Marconi plus D3F Netrik sockets 5000 +Jack Muirhead D 746 A Impedance Converter D.F.M. TF2430, Interlab SQ10 S19, Gen sockets 100,000 plus pots 2 x Arso air £20. etc. etc. 040-376236. (20161 Linstead E.V.M. M2B, Kingshill dual conditioners, banding machines etc, etc, p.s.u. 36V5C 4 x DB300A P.S.U's Dave Roberts 051 227 1919 Day 051 428 Venner digital counter 7734, Fluke 1845 evenings. 128 MODEM CHIP AM7910 (With Data), digital multimeter 217 £17.80 inc. VAT /P &P. I/C sockets, turned pin contacts on terminal carriers, fraction cost price. Also comprehensive WAVEGUIDE, Flanges and dishes. AIÌ standard Quantities of surplus capacitors 15000 TELEQUIPMENT 'SCOPES, valve stocks. Lists of both, S.A.E. sizes and alloys (new material only) from stock. mfd., 40 volt approx, and PO style relays Spares, Manuals. S54A, £125. Philips 10 Access /B'Card. Linway Electronics 843 Special sizes to oder. Earth Stations, 01 -228 approx 10000 ohms coil. Telephone MHz. £100. Test Gear. Ochremill 0785 Uxbridge Road, Hayes End. Middx. UB4 7876, 221lowie Street, London SW 114AR. (2099) (0243)861221. 214 814643. (165) 8HZ. Tel. 01 -573 3677 220 ELECTRONICS & WIRELESS WORLD MAY 1986 77

www.americanradiohistory.com Classified

G.W.M. RADIO LTD., 40/42 Portland FIGOLLEDGE{ Road, Worthing, Sussex. Test MANUFACTURERS SURPLUS STOCKS equipment, receivers, oscilloscopes, Radiotelephones, Computers, components etc. Marine equipment, For ----/ELECTRONICS Electronic Components, Test Gear, Sale and Wanted. Large or small lots. - Photographic and Video Equipment. All at knockout prices. Many miscellaneous bargains for callers. QUARTZ CRYSTALS Trade Enquiries Welcome. OSCILLATORS AND FILTERS of Export and Amateur equipment stocked. A.V.O. 8 Catalogues Available from: with case and leads £60 inc. V.A.T. and all types. Large stocks of standard items. P A.V.O. £35 meter only checked and Specials supplied to order. Personal and ELECTRONICS, 5 STATION ROAD, &P. SAE for lists B. BAMBER in good order. Tel. 0903 34897. 213 export orders welcomed - please. OEM support thru:- design LITTLEPORT, CAMBS. Phone: ELY 103531860185. advice, prototype quantities, production 19" RACK MOUNT schedules. CASES. Industrial Quality Fully Golledge Electronics. Merriott, enclosed with separate chassis. Somerset TA16 5NS. Tel: 0460 73718 1U x 250mm depth at £18.84 (2472) lU x 300mm at £21.35 2U x 250mm at £22.05 2U x 300mm at £24.69 3U x 250mm at £25.22 3U x 300mm at BRIDGES waveform /transistor analys- NOW AVAILABLE - Bumper SPECTRUM ANALYSER software £27.99 P &P £3 +VAT. Also 4U sizes ers. Calibrators, Standards. Millivoltme- Catalogue - 170 pages - for collectors of for BBC B microcomputer, based on Newrad intrument cases. Unit 19. Wick ters. Dynamometers. KW meters. Oscillo- vintage radio, audio & T/V equipment. machine -coded FFT. Including graphical Ind. Est. New Milton, Hants. BH25 6SJ. scopes. Recorders. Signal generators - Price: £2.00 post paid U.K., £3.00 post display, calibrated measurements, Tel: (0425) 621195. (181) sweep, low distortion, true RMS, audio, paid overseas. Vintage Wireless Co., manual. £120 Details from: Structured RM, deviation. Tel. 040 376236. (2616) Ltd., Cossham Street, Mangotsfield, Software 14 Athelstan Close, DESIGN Low Cost Bristol BS17 3EN. Phone 0272 -565472. Bromborough, Wirral, Merseyside. L62, PCB ARTWORK (197) 7 -Day Turnaround *Prototype PCB's (208) 2EX. 'Circuit Design 'Call Systems 'PCB hand assembly. Phasor Circuits, 12 USER Rushey Mead, Leicester. QUALITY Kendal Rd., EQUIPMENT m Trransllab. TELEQUIPMENT SPARES Tel. 0533 830953 (209) your requirements we can Genuine parts at give away prices Whatever Send us a sample PCB's MANUFACTURED. help. Oscilloscopes, signal analysers, example. Scope probes TP5 X1 -X10 TP2 Exporting to U.K.? have a huge (X10) at only £5.49 incl. VAT. Plus large board sod all components to produce to prototypes, small /large production runs, power supplies, etc. We here at home base. selection all fully refurbished to original selection of popular electronic your reuirements single, double sided, P.T.H screen (0602) Wave soldering etc.,same applies to U.K. printing, panels, labels, solder masking & manufacturers specification with components. Nottingham warranty. Send now for our free price -list 587225/587241. High Speed Technology Mainland companies. Interested? photography. Orbitechnic Circuits, The Telephone: Walton -on- Thames (0932) Road, Ilford, to Translab Electronic Services, 38 Ltd., Technology House, Prospect Road, rear of 127 Woodlands Nottingham 4G4 1LA. (231) 220612 24 hour telephone answering. Essex. Tel: 01 -553 5211. (154) Matlock Close, Rugby CV21 1LB. 227 2a Carlton,

WANTED SERVICES CIRCOLEC THE COMPLETE ELECTRONIC SERVICE PCB Assembly, Test & Repair Service, Q.A. E C COMPONENTS Artwork, Circuit Design, WANTED Consultancy, Prototypes, Final Assembly. Full PCB Flow Soldering We buy large and small parcels Service. Test equipment, receivers, of surplus I /C, transistors, capa- Quality workmanship by professionals at economic prices. valves, transmitters, com- citors and related electronic Please telephone 01 -646 5686 for advice or further details. ponents, cable and stock. Immediate settlement. TAMWORTH MANOR electronic scrap and quan- Tel: 01 -208 0766 302 -310 COMMONSIDE EAST, MITCHAM service and Telex: 8814998 (1391) tity. Prompt (2491) cash. Member of A.R.R.A. M &B RADIO 1. B CI CCT ONICS TOTAL SYSTEMS DESIGN 86 Bishopsgate Street B.D c Specialisingl in the design and manufacture of Leeds LS1 4BB USED TEST EQUIPMENT 0532 435649 Industrial control and data acquisition systems (995E5 FOR SALE & WANTED applications consultancy electronics Buyers & Disposal Officers Contact Offering design and software compilation COOKE INTERNATIONAL Site Unit 4 Fordingbridge Please telephone 0622 - 674192 Main Road Barnham Bognor Regis 11 Broomshaw Road Maidstone Kent ME16 9HS FOR West Sussex P022 OEB Tel. 0243 68 511112 (179)

CLASSIFIED DISC COPYING! ADVERTISMENTS FORMAT CONVERSION WE USE * MICROCOMPUTERS We can convert your files to and from most CPIM, MS- ONLY 10% DOS look alike) disk formats and sizes. * PERIPHERALS (and RING [7.50 + Disks (if required) + VAT OF OUR * INSTRUMENTATION For details contact Clive Waller at Chiatronix Ltd, 238 Old Bedford Road, Luton, Beds, MENTAL SUSAN PLATTS For fastest, best CASH offer, phone, Tel: 21010 LU2 7EQ (05821 POTENTIALS COMPUTER APPRECIATION (Callers by appointment please) Oxford (0865) 55163 661 3033 These are the words of Albert Einstein. the Telex 838750 greatest physicist of recent times. (2492) L. Ron Hubbard's discoveries in the field of TURN YOUR SURPLUS i.cs transistors the mind prove today that Einstein was right. cash, immediate settlement. We In his book "DIANETICS: The Modern etc. into L. Hubbard to quote for Science of Mental Health" Ron 7 also welcome the opportunity takes one more giant step in this direction. complete factory clearance. Contact He reveals how anyone can use his When replying to classified the exact barriers that & CO, 103 South discoveries to isolate STEWART OF READING COLES- HARDING have so far prevented people from using their Brink, Wisbech, Cambs. 0945 mental potentials to the full. 110 WYKEHAM ROAD More and more people from all walks of life advertisements, readers are 584188. (92) use Dianencs technology today. 1 READING RG6 PL The many written reports on their success TEL NO: 0734 68041 are the best proof of the quality of this book. recommended to take steps to Find out for yourself. Order your copy of this RF- I)esign, development, prototyping, remarkable book today. TOP PRICES PAID FOR Price 13.95 paperback E17.50 herdback. hatch production. HF /VHF RX /TX, etc. flake cheques and P.O.s payable to S.H.F. protect their interest before ALL TYPES OF SURPLUS Hill assistance. Phone 07918 Send to'. Church of Scientology Saint TEST EQUIPMENT, For help and Foundation, FREEPOST IWW 1I East Grinstead, her , e ,]A stamp requiiedl. COMPUTER EQUIPMENT, 6149. NOw (24hr ansaphone). WPO Sussex %no sending money (25191 COMPONENTS etc. Communications, 20, Farnham Avenue, ANY QUANTITY. 103' Hassocks, Sussex. BN68NS. 212

WORLD MAY 1986 78 ELECTRONICS & WIRELESS

www.americanradiohistory.com ARE YOU MAKING THE MOST OF YOURSELF London -Yorkshire Motorway: Route M1 WHY NOT FURTHER YOUR Major Maintenance: 1986/87 Programme TRAINING IN ELECTRONICS? Provision of Site Radio Telephone System We offer: Applications are invited from companies wishing to be CNAA B ENG. IN ELECTRONIC ENGINEERING considered for the supply and maintenance of this system on A four year part -time degree course for those working in industry. The is Attendance one full day each week. The course is based upon modern the basis of a medium term hire contract. equipment to electronic engineering with a strong computing theme. be used for a period of approximately four months during the in Bedfordshire. Entry Qualifications: BTEC HNC or equivalent in Electrical and maintenance programme South Electronic Engineering or Applied Physics. Companies wishing to be considered should apply to: BTEC HND ELECTRONIC ENGINEERING The County Surveyor, County Hall, Cauldwell Street, A two year full -time course which combines an up -to -date technological BEDFORD MK42 9AP. education with a considerable 'hands on' experience of a wide range of modern equipment and techniques. Entry Qualifications: One pass at 'A' level in an appropriate subject, or a BTEC Certificate or Diploma or equivalent. I BTEC HND IN ENGINEERING (SOFTWARE) Iii (subject to approval) A Nuclear Free Zone (202) A two year full -time course is designed with industry to provide the education, including hands -on experience, which is essential for a software engineer. The course also provides basic engineering training as specified by the EITB. SENIOR DESIGN ENGINEER required to join a rapidly expanding Entry Qualifications: One pass at 'A' level or a BTEC Certificate of electronics company researching and developing video and hi -fi products. Diploma; the final selection will be by interview. A degree in electronic engineering and a minimum of five years experience SHORT COURSES IN ELECTRONIC ENGINEERING in the field of analogue engineering is required. Experience with digital or A number of short courses are provided each year on topics which include audio design would be advantageous but not essential. The successful analogue or digital microprocessors, digital signal processing and candidate should be self- motivated and able to work with the minimum of computer aided circuit design. These courses normally include hands -on supervision within a small research laboratory developing high quality experience. products. Since the company has divisions in the U.S.A. and the Far East there may be opportunities for travel. Salary will be negotiable but will be Additional courses may be provided in response to specific request from commensurate with this important position. industry. For further details contact the department of Engineering, Please send CV to: Pat Kerridge, Technical Cambridgeshire College of Arts and Technology, Cambridge CB1 1PT. Secretary/Administrator, NAD NAD Electronics Ltd., TELEPHONE (0223) 352973 or 352979 Adastra House, 401-405, Nether Street, CAMBRIDGESHIRE COLLEGE OF London, N3 1QG or telephone 349 4034 for further information. 78) ARTS AND TECHNOLOGY (169)

'data= mu nu VLn 'Drama I J Use this Form for your Sales and Wants PLEASE INSERT THE ADVERTISEMENT INDICATED ON FORM BELOW To "Wireless World" Classified Advertisement Dept., Quadrant House, The Quadrant, Sutton, Surrey SM2 5AS Rate £4.50 PER LINE. Average six words per NAME line. Minimum £36 (prepayable) Name in if and address to be included charge ADDRESS used in advertisement Box No. Allow two words plus £10 Cheques, etc., payable to "Business Press International Ltd." and cross "& Co." 15% VAT to be added

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Wurelessworrn INDEX TO ADVERTISERS Appointments Vacant Advertisements appear on pages 74 -79 PAGE PAGE PAGE PAGE Ralfe Electronics 69 ABI Electronics Ltd 65 Electronic Brokers IFC, 3, OBC Langrex Supplies Ltd 39 40 EMS Mfg. Ltd 66 Leetronex 62 Research Communication 11 AEL Crystals Robot (UK) Ltd 49 Airlink Transformers Ltd 42 E &WW Smartwatch Offer 65 Level] Electronics Ltd 9 Amateur Radio Promotions 73 Lincoln -Sinns Ltd 2 MAP 80 Systems Ltd 50 Ltd 2 Field Electric Micro Concepts 66 St. Ives Windings Ltd 14 Barrie Electronics Ltd 49 Fulcrum (Europe) Ltd 14 Beckenham Peripherals 11 Microkit Ltd 35 Sarei Ltd 10 MicroProcessor Engineering Ltd Service Trading Co. Ltd 40 69 Sherwood Data Systems 14 Kits 14 Cambridge Hameg 73 Midwich Computer Co 5 Silicon Glen Ltd 35 Cambridge Microprocessor 50 Monolith Electronics 35 Sowter, E.A. Ltd 66 Ltd 41 Happy Memories Systems Harris Electronics (London) 41 MultiPower Electronics 2 Stewart of Reading 10 Carston Electronics Ltd 4 66 Strumech Engineering Ltd 15 PLC 73 Harrison Electronics Cirkit Holdings Hart Electronics Kits Lb! 69 Network Satellite Systems Ltd...41 Surrey Electronics Ltd 48 Computer Appreciation 66, 80 Number One Systems 4 48 Henry's /Audio Electronics 80 Computer Source 48 Ltd 48 Henson, R. Ltd Control Universal Hilomast Ltd 50 Personnal Computers 15 Crash Barrier 11 40 Taylor Bros (Oldham) Ltd 35 10 Pineapple Software Crossware Products PM Components 12/13 Technomatic Ltd 70/71 Crotech Instruments 41 Tektronix (UK) Ltd IBC Applications 42 62 Cybernetic Johns Radio Quadrant Picture Library 4 Thandar Electronics 15 Thurlby Electronics 72 49 Radiocode Clocks 2 TIC Semiconductors 11 Dataman Design 61 Keithley Instruments Triangle Digital Systems 62 Display Electronics 16/17 Kestral Elect. Comp 4 Raedek Electronics 42

OVERSEAS ADVERTISEMENT AGENTS Francs and Belgium: Pierre Mussard, 18 - 20 Place de la Madeleine, Paris 75008. NY 10017 Telephone (212) 867 -2080 Telex: 23827. United States of America: Jay Feinman, Business Press International Ltd, 205 East 42nd Street, New York, - -

proprietors, Business Press International, Quadrant House, The Quadrant, Sutton, Surrey SM2 SAS. Primed in Grat Britain by Ben Johnson Printers Ltd., Oldhill, Dunstable, and typeset by TypeFast Ltd., 2-6 Notthburgh St., London EC I, for the & Gotch Ltd. INDIA: A.H. Wheeler & Co. CANADA: The Wm. Dawson Subscription Service Ltd., ©Business Press International 1986. Wireless World can be obtained from the following: AUSTRALIA and NEW ZEALAND; Gordon Inc., 14th Floor, 111 Eighth Avenue, New York, N.Y. 10011. Gordon & Gotch Ltd. SOUTH AFRICA: Central News Agency Ltd; William Dawson & Sons (S.A.) Ltd. UNITED STATES: Eastern News Distribmion

80 ELECTRONICS & WIRELESS WORLD MAY 1986

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