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XY plotter update

Mobile radio

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Australia AS 3.00 Norway Nkr 29.20 -Denmark DKr 34.50 Singapore MS .5.50 LSermany Dm 7.00 Spain Pts 340.00 Greece Dra 220.00 Switzerland SFr 7.00 Holland DFL 8.50 U.S.A. 5 3.75 Italy L 3800,

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ELECTRONICS & WIRELESS WORLD DECEMBER 1984 1

www.americanradiohistory.com Wireless°uüörld over 70 years in independent electronics publishing

December 1984 Volume 90 number 1586 FEATURES 17 37 56 Music keys for the BBC HDTV or EDTV? Semiconductor microcomputer by Tom Ivall suppliers by R.M. Adelson IBC 84 exposed some Who deals in the Software for the investigations into components you need? polyphonic keyboard methods of obtaining And which companies will interface described higher -definition accept private orders?. earlier. television pictures. 69 21 43 Mobile radio systems Multiplexing Hand-held and techniques liquid -crystal displays multimeters by N.S. Cawthorne by T. Segaran Price and performance Report from the York IEE A short description of the data. conference. `black art' of led driving. 23 46 74 More on the XY plotter Speed of light Multi -standard modem by P.N.C. Hill by Roy Hodges Further information on An attempt to explain its by Richard Lambley construction, and constancy, even when the Modifications for line -drop software. light source is in relative problems, and BBC computer connections. motion. 78 31 51 Digital derivative Mimi -controller feedback at I.f. Intelligent eprom Nicholls by J. Rush by Peter programmer A dedicated controller, Hybrid digital -analogue using the 6502, frees a by John Adams rate -information microcomputer for other Computer control software extraction is more duties. and construction. effective than a RC circuit. REGULARS 6 64 82 Comment and News Letters New Products Comal versus Basic: Energy transfer: Flat-bed plotter: BBC engineering designs: relativity: personal logic analyser: Acorn business computer: Baird: multi -tasking Forth: Voicemail. d.c. supplies. picoammeter. 25 71 Communications Circuit ideas Optical power: One led shows six modes: microwave landing: combination lock: 405 -line tv: audio differential line IARU locator: costly h.f. transformer uses op -amps.

www.americanradiohistory.com CONTRoi Front cover is a Editor olelrs Richard Newport PHILIP DARRINGTON design, illustrating 01-6613128 cilities Minicontrollerim1C0ntr°llerand this month's survey of m Deputy Editor Given Beambly-languaedel $Révlopiugaprob semiconductor GEOFFREY SHORTER, B.Sc. afBCoo controlleruompúpermwcenttSae takes°ver availability. ldiuuconller 01-6618639 economicalbca ti2s m,{ such Technical Editor Mee'. NEXT MONTH aF ,.N MARTIN ECCLES Single -board computers 01-6618638 nee Ñ mx of dNYn{ ^ mwe are the subject our latest BP,N market scan, in which Projects Editor one d mann, Martin Eccles gives a brief RICHARD LAMBLEY mdu,inals aaxm v¡A 1íEJ udl ,M.t outline of what they are 01-6613039 Núkn.2á;kº *Ole* and their applications. A Tal,11 SIANDMID - table of specifications for News Editor currently available units is ,Muestandard included. DAVID SCOBIE by gichaid 01-6618632 l,ambley In°dern John Linsley Hood and 1° Odificauons Drawing Office Manager Connections m.,.., presents his views on fully ROGER GOODMAN Pe..IldkcmUmnairo symmetrical audio

Mt,ÿyBpdNAºp ¡heta dun '^aiem.'BIN amplifiers, with practical 01-6618690 aadet pa°nµnºa`dZ!iuF+ todNmíNn s.a VBSC1Mv^hna°4 °ºtWwt d.. the aro.. 815 circuits for a moving -coil head amplifier and a gain Technical Illustrator iBmeddreuVPº block. BETTY PALMER

rt/rdºa° IaPoc aMn1Fe - `' - t-, anymoa 1M n°Y AMiM ,nÑ cr ,Naaemuºw on oxen, dtu mxwn ^` ;,ndN Compact discs are n" mvene'ºWm A,didi Advertisement Manager a.,Miw., 'AK becoming well -established and John Watkinson gives BOB NIBBS, A.C.I.I. 01-6613130 Pw"Illt a short overview of the xY ;. making of discs and the the Art MICHAEL DOWNING Nill method of playing them. F.N.C. More Ó 01-6618640 bY and some ntice ation .m Safa Omran's design for a plotter inform A,m constructional .te, video ASHLEY A camera/computer WALLIS 1. V`°` .u-`2d. Further pº m ,Fa9 SOftWatedu`µ, 0 n yK num. xa n interface stores eight 01-6618641 Mm' pixels at a time, reducing {nn the time for storing a dea trnn Northern Sales s inn of picture by a factor eight. HARRY AIKEN B,N.;;; a 061-872 8861 scm, mW Current issue price 85p, back issues (if Fic2. Fn{neVo`ena,dWn^. available) £ 1.06, at Retail and Trade Counter, Units 1 & 2, Bankside Industrial Midland Sales Centre, Hopton Street. London SE 1. Available on microfilm; please contact editor. BASIL McGOWAN By post, current issue £ 1.30, back issues 021-356 4838 (if available) £ 1.40, order andpayments to EEP Sundry Sales Dept., Quadrant House, 1'he Quadrant, Sutton, Surrey SM2 5AS. Classified Manager Tel.: 01-6613378. Editorial & Advertising offices: BRIAN DURRANT Quadrant House, The Quadrant, Sutton, 01-6613106 Surrey SM2 5AS. Telephones: Editorial 01-661 3614. Advertising 01-6613130. See leader page. IAN FAUX Telex: 892084 BISPRS G (EEP) Subscription rates: 1 years £ 15 UK and 01-6613033 £ 19 outside UK. Student rates: 1 year £ 10 UK and £12.70 outside UK. Production Distribution: Quadrant House, The BRIAN BANNISTER Quadrant, Sutton, Surrey SM2 5AS. Telephone 01-6613248. (Make-up and copy) Subscriptions: Oakfield House, 01-6618648 Perrymount Road, Haywards heath, Sussex RH16 3DH. Telephone: 04444 59188. Please notify a change of address. Publishing Director USA: S49.40 surface mail, S102.60 airmail. Business Press International DAVID MONTGOMERY (USA). Subscriptions Office, 205 E. 42nd 01-6613241 Street, NY 10017. USA mailing agents: Expediters of the Printed World Ltd, 527 Madison Avenue, International Agents and Suite 1217, New York, NY 10022, 2nd class the Advertisers Index postage paid at New York. © Business Press International Ltd 1984. appear at the back of this ISBN 0043 6062. issue.

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1 x PP3). withAGCforAM/SSB 61-04412 1.95 68000: Principles and Programming 02-21853 12.70 DC Volts: 0.1V, 0.5V, 2.5V, 10V, 50V, 250V, 1 kV ICM7555 Low power CMOS version Cookbook 02-21697 13.55 (20k0Z/V). AC Volts: 10V, 50V, 250V, I kV (18kCl/V). of55timer 61-75550 0.98 8085A Handbook of Electronic Tables DC current: 50µA, 2.5mA, 25mA, 250mA. Low noise FM IF 61-11225 1.45 HA11225 Formulas 02-21532 11.00 Resistance: 2k, 20k, 2M, 20Mz. AF Output: -10dB to HA12017 83dB S/N phono preamp Popular Circuits: Ready +22dB for 1 OVAC (0dB/0.775V, 6000). Leakage 0.001%THD 61-12017 0.80 leference 02-04585 13.95 (Iceo)15µA,15mA,150mA. Hfe: 0-1000 (Lc/lb). MC14412 300 baud MODEM controller Semiconductor Data Book Weight:910gms. 56-83201 14.00 (Euro/USspecs) 61-14412 6.85 11th Edition 02-04797 9.00 CIRCLE 16 FOR FURTHER DETAILS. 4ek

9` .44,4 /9 www.americanradiohistory.comff NEWS COMMENTARY

BBC design GOTO Sweden display too), produces a lurid multi-coloured chequerboard The new computer for Swedish what is going on. designed to reveal schools described in these pages With one or two honourable maladjustments of phase and last month must have whetted exceptions, the Basic on most saturation in colour monitors. quite a few appetities (ours home computers is indeed pretty BBC engineers pointed out included), pointing the way as it awful. And it seems to be the that the digital decoding process undoubtedly does towards the untidiest features of the language adopted in their new decoder is next -generation educational that the average schoolboy learns not the same as that used in the computer over here. first. Walk into your local compu- new digital television sets from The fetchingly -named Compis ter store, and like as not you'll ITT: in those, decoding is by is a 16 -bit job with 128K of mem- find a group of 12 -year -olds work- the conventional method, ory plus a separate graphics pro- ing on a program which says although in the digital domain. cessor giving a 1280 by 800 pixel Also in the television field display, with word-processing 10 PRINT "KEVIN IS A WALLY" was a range of new u.h.f. and communications facilities A digital PAL decoder designed receivers. BBC engineers have thrown in, all for a price of around 20 GOTO 10 by the BBC was one of a found that most commercially £1,000. Set beside that, the BBC number of new developments produced receivers perform Micro, for all its qualities, begins Only one home computer has shown at a series of open days little better than domestic to look a little old fashioned. been offered in Britain with a staged recently by the television sets. For one thing, One interesting feature of the standard language other than Corporation's designs they adopt (for reasons of cost) new machine is the decision by its Basic: the late lamented Jupiter department. the intercarrier sound makers to adopt a version of Ace, which came with Forth. Unlike a conventional colour technique, which necessitates Comal -80 as the standard lang- In its several versions, Forth is tv decoder, which uses sacrifice of the higher vision uage in preference to Basic. probably the next most popular bandpass and notch filters to frequencies to avoid sound -on Comal is an interpreting language language after Basic. But how separate the colour information vision interference. which provides a bridge between useful is it to the average key- from the luminance signal, the The BBC's own receivers are Basic and the highly structured board hacker? It's fine for what it's digital decoder uses comb necessarily much more compiling language Pascal. good at - real-time hardware filtering. By making use of the complex. At the top of the range Basic has long been the subject control and whatnot - but as a spectral separation between the is a synthesized receiver of criticism by programming pur- general-purpose medium for dut- brightness information and the designed to provide a ists on the ground that it puts no ies such as drawing pictures and colour sidebands, comb filtering programme feed for television premium on tidy thought. And a processing text strings, it's noth- makes it possible to retain high relay stations. This features an quick glance at the contributions ing like as convenient as Basic. frequencies which would interdigital filter tuned to the from readers in some of the home So now that computer studies otherwise have to be thrown wanted channel at its front end, computing magazines provides a have taken the place of the clas- away to prevent unacceptable an image -cancelling mixer, an good deal of support for that argu- sics as a discipline for the brain, it patterning. The result is a sharp exalted -carrier detector and ment: everywhere you see list- will be interesting to see what picture almost free of the usual some specially manufactured ings festooned with Goto state- benefits Scandinavia obtains from twinkling dots on colour surface acoustic wave filters to ments and peppered with peeks switching to Comal . For when the boundaries. ensure a good amplitude and and pokes. Short of laboriously eventual replacement for the BBC Good quality PAL encoding group -delay response. In the tracing each program through line Micro comes along, perhaps we and decoding is of importance in mixer, the signal is fed in by line, it's impossible to discover shall want to do the same. broadcasting, for until the day quadrature to a pair of schottky when the `islands' of digital diode ring mixers, the output of processing within the which is combined so as to broadcasting chain finally cancel the unwanted image. coalesce into an all -digital Provision has been made for a Robots in the lab whole, a signal may have to be digital stereo sound output. Those interested in using small The laboratory has decoded and recorded many For less demanding robots in laboratories are commissioned the construction times before it reaches the applications another u.h.f. invited to join the Laboratory of a prototype arm designed public. And any defects in the receiver is available: this comes Robotics Club. The Club has specifically for use in such process will be compounded. in synthesized or voltage tuned been formed by representatives activities. The club will provide: The new unit uses 8 -bit versions with local or remote from the Laboratory of the dissemination of information via conversion, with 12 -bit internal tuning and it too features a low - Government Chemist and from newsletter, meetings and a processing to avoid rounding distortion demodulator and other industrial and academic technical information service; errors. The comb filter which special s.a.w.fs. laboratories. access to consultancy services; separates chrominance from The BBC has for some years At the Laboratory of the opportunities to collaborate in luminance operates in both the been using a digital sound-in- Government Chemist, the research and development horizontal (line -by-line) and syncs technique for distributing Automation and Instrument projects; and sponsorship of the temporal dimensions. The tv sound: besides saving the Development Group is development and manufacture results are very impressive, cost of separate music lines this developing an automated work of specialized instrumentation. even on very demanding test ensures that the sound cannot station based on a small robot Further Details from D.G. signals such as the 'zone plate' get lost in transit. But now the arm. This will be capable of Porter, Laboratory of the pattern of concentric rings and technique has been taken a step such operations as weighing, Government Chemist, Cornwall the BBC's new SLUG test further to provide stereo sound. homogenizing, dispensing and House, Stamford Street, signal. SLUG, which stands for The system uses a sampling transfer of liquids, centrifuging, London SE1 9NQ. saturation and line-up generator rate of approximately 32kHz filtering, stirring and heating. (and this equipment was on (twice line frequency) with 14 6 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com maintenace staff have a small telemetry receiver fitted with a s on show dot-matrix text display. The same system is being used for safety monitoring of bits per sample. The data men working alone on isolated stream is transmitted during the sites. The engineer has to push line sync. pulse and burst of a button every so -often - and four -level pulses. Before if he forgets, the rescue team is transmission to the public this dispatched! signal would, of course, be With the introduction of 24 - stripped off. hour broadcasting on Radio 2 it One development aimed at has become more difficult for making life easier for television the engineers to ensure good production staff is a new time - transmission quality, since there code converter. To help in is now no time at which they identifying edit points, an 80 -bit can test the equipment. time signal is distributed around However, they believe they have the studios and is recorded by now obtained a tacit agreement the v.t.r. on an audio track. But from the programme controllers when the producer goes way for an occasional half -minute of with a cassette of the day's engineering tests. These would takes, this signal is usually left no doubt have to be carried out behind, since most domestic during the small hours of the Acorn means business v.c.rs have only one sound morning, since there is as yet Acorn Computer, manufacturers you to write, i.e. type the channel. The new equipment no way of disguising a frequency of the BBC and Electron micros memo. The model 300 uses the inserts the time code into the sweep as programme material. are about to launch a series of Intel 80286 16 -bit processor, vision signal on a suitable line But Designs Department have business computers. There will and the Digital Research in the vertical interval. The data now constructed some be eight models in the series. Concurrent operating system can then later be extracted and equipment for making short At the lower end is a word -and - supports applications written displayed, even at slow-motion tests of this sort, based (like data processor with a for PC DOS, MS DOS and CP/ or in stop -frame. Having chosen several other items on display) specification similar to that of a M 86, ensuring that there will his edit points off-line, the user on a BBC Microcomputer. This BBC micro with the View and be a wide range of software can store the codes on a floppy low-cost system scans the Viewsheet programs and a already available. The system disc from which they can be network for a signal to start the built-in disc drive, capacity can also perform several tasks recovered back at the studio. test, which consists of a 640Kbyte. The 'flagship' of the at the same time and is suitable series will be the ABC 300. for the development of Software compatible with the integrated, multi -function IBM PC, It offers a desk -top software packages. The CSQ® II®113 n, 18 r' manager with icons. For those computer has twin floppy drives unfamilar with the terminology, and a monochrome monitor, ®`#4:41 a. ®®®13 the screen is arranged like the while model 310 adds a ElD surface of desk so that in order 10MByte hard disc and colour. 811111111111111111111111111111111111111111111111111111.11111111118111 to write a memo, instead of All the ABC models can be reaching for a memo pad, you networked through the Econet BBC Television and the frequency run and a 15s period point an arrow on the screen to system and can have built-in domestic radio services now of silence for noise the picture (or icon) of a memo modems. Prices are yet to be have a very large number of measurements. Afterwards it pad. The program then invites announced. transmitting stations dotted displays the results. about the country, and the great For distributing radio majority of these now are programs a new radio link unattended. Maintenance of the operating in the 1487-1492MHz Voices in the computer networks is carried out by a band was shown. The BBC has Electronic mail is all very well selected sales staff at 10a.m. small number of crews been allocated four of the ten but each user needs to have a next Tuesday. The p.c.m. operating from regional centres; 500kHz channels in this band computer to operate it. Now BT digitized speech is recorded and these crews need and is using the 'tamed f.m.' Merlin have come up with a onto a Winchester disc which immediate warning of any technique developed by Philips system very similar to has sufficient capacity for a mishaps at the transmiitter to squeeze in a 676kbit/s digital electronic mail but using large number of messages and sites. stereo signal. This system, like digitized recorded speech. It further disc drives can be added Such warnings are sent by one or two other exhibits, has can be used from any remote to increase the capacity. Our automatic reporting equipment now been licensed to a telephone, almost anywhere in impression was that the which dials up the local commercial manufacturer. the world. Messages can be messages were perfectly clear monitoring centre and sends a Developments in studio made available to all who and much better than any code number corresponding to equipment, both in radio and contact the base station or may synthetic speech which we the fault. To alert the crews, television, have been be given passwords so that only suppose could be an alternative. this information can now be proceeding rapidly with the those for whom they are One minor problem is that the broadcast as a data signal on growth of digital processing and intended can receive them. system requires a dedicated one of the v.h.f. radio the evolution of new EBU Messages can also be coded so minicomputer and this makes networks. The code number is interfacing standards. But that they are not made available the system quite expensive, converted into Ascii text and analogue equipment, which still before a specified time. So it is though claimed by Merlin to be sent as a low -rate d.p.s.k. comprises the bulk of the possible :or a sales director, for very 'cost-effective'. The entire signal on a 76kHz subcarrier. broadcasting chain, has not example, to record a message package is devised and For a read-out device, been forgotten. which will be delivered to manufactured by Ferranti. ELECTRONICS & WIRELESS WORLD DECEMBER 1984 7

www.americanradiohistory.com NEWS COMMENTARY

Space station Columbus

Discussions are currently taking to be settled. station. Other possibilities for place for the possible extension Meanwhile the American at collaboration are also being of the European Spacelab NASA are forging ahead with looked at. The potential project into some form of similar plans but on a very practical use for such space orbiting space station. One grand scale. The same three- stations falls into four project, called Columbus, was part system is envisaged but categories: those which take originally proposed by Germany with possibly several manned advantage of the microgravity and Italy. A preparatory modules and unmanned and vacuum environment for programme has been initiated platforms. Assembled in spce, experimental or commercial by the European Space Agency. the Nasa space station could purposes; the use of the station Columbus is being thought of as expand to accommodate a crew as a permanent statellite; the three modules: a manned of 18 by the year 2010. NASA testing of technologies for later pressurized module which is also investigating the part use in space; and the servicing would provide a working that robotics could play in the of satellites. Microgravity environment for scientists; a running of the station. The research has already indicated payload carrier or space platforms would be re -useable that it is possible to produce platform to act as a base for carriers for experiments, highly pure pharmaceutical unmanned experiments; and a sensors etc. NASA has invited chemicals by electrophoresis. resource module which would participation from other space Metallurgy and electronics are provide power and propulsion agencies including ESA and it is though to be other areas where for the whole system. Details possible that Columbus could be high -value products could and even which ESA member developed as a European benefit from processing in states will participate have yet contribution to the NASA space.

RFI and computers

The British Standard Institution standard specifying the limits of will meet a current and have published a new standard, permitted r.f. interference caused increasing need. BS 6527 covering a Specification by computer in either the Copies are available from the for limits and measurements of domestic or commercial area, BSI Sales Department, Linford spurious signals generated by but as such equipment becomes Wood, Milton Keynes MK14 data processing and electronic more widespread, the standard 6LE, price £ 10.20. office equipment. Such equipment can cause interference bourne through the mains cables or direct radiation causing interference to radio reception. The new standard is the first to specify limits for the levels of TV news from anywhere these spurious signals in order to reduce to an acceptable level the No sooner had we got used to size with high efficiency and a probability of the incidence of the idea of e.n.g. (electronic radiation pattern meeting the 2 - radio interference from sources news gathering), then GEC - degree satellite -spacing in both domestic and commercial McMichael come up with requirement. The dish areas. Measurement of limits is another idea, s.n.g. or satellite measures one metre high by at mains terminals in the news gathering. This consists of two metres wide with an offset frequency range 150kHz to a small, portable satellite earth feed, all held in a universal 30MHz and of field strength from terminal which may be flown in frame enabling the dish to be 30 to 1000MHz. a light aircraft to anywhere in aimed at the satellite. The The limits and methods of the world and transmit news transmitted 14GHz signal is measuring them are based on back via any handy boosted by a fet amplifier to work currently in progress within communicationd satellite which 4.8W, carried to conical horn the International Committee on can receive the up -link feed of the antenna by a wave - Radio Interference (CISPR). frequency of 14 to 14.5 GHz. guide. Another contribution to This Standard will help to The s.n.g. terminal can also the small size of the unit is the overcome the anomoly of British receive narrow -band signals for use of a coder similar to those computer manufacturer making audio and so can be given used in teleconferencing which equipment without any instructions by the home only transmits the changing protection suitable for the broadcasting station. The whole information in a tv picture and domestic market and then having system is powered by a 12V thus allows a much narrower to substantially alter the designs battery or local mains, if bandwidth. This can give a in order to comply with the available. blurred image to any fast- standards in other countries, for The compactness of the moving part of the picture but it example the FCC regulations in system has been achieved by is though that this is acceptable the United States. At present the design of an elliptical in situations where the events there is no agreed international antenna which combines small would normally be inaccessible. 8 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com TO GET DIGITAL CAPACITANCE MEASUREMENT IN THE PALM OF YOUR HAND.. The NEW Model 3000 digital capacitance meter makes it easy to lay your hands on a precision test instrument. Our battery-operated portable meter has the featuresyou expect from a larger meter - with a 32 digit resolution, accuracy to 0.2% of reading, capacitance

measurements of 1 pF to 2000µF and switch selection of capacitance range. You get a large, easy -to -read LCD with 'early warning' display to tell you when the battery is low or if there is excessive compensation of stray capacitance. Stray and incidental capacitance is then easily nullified by the front - panel zero ADJUST control. You get the convenience and low cost of a portable meter! Hardly bigger than the palm of your hand, the Model 3000 runs on an ordinary 9V battery and comes with a tilt stand for easy positioning. Send for a specialist! Order your 3000 Digital Capacitance Meter today! If you're not completely satisfied, simply return the meter within 3000 DIGITAL 14 days and we'll refund your payments. CAPACITANCE METER ONLY £89.50 plus VAT YOU NEED TO SEEA SPECIAL IST'

To: GLOBAL SPECIALTIES CORPORATION (UK) LIMITED, DEPT 7T Unit 1, Shire Hill Industrial Estate, Saffron Walden, Essex CB 11 3AQ. . Please send me 3000 DIGITAL CAPACI TANCE ME TER(S) at £105.80 each (inc P&P and VAT)

Please send me a free catalogue and more information! Name Company/Address

GLOBAL Telephone

SPECIALTIES 1 enclose PO/Cheque for £ or debit my Barclaycard/Access/ An Interplex Electronics Company . No exp date Shire Hill Industrial Estate, Saffron Walden, Essex, CB11 3A0. . American Express EWW 12/84 Telephone: (0799) 21682 Telex: 817477 GSC LTD CIRCLE 14 FOR FURTHER DETAILS.

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 9

www.americanradiohistory.com DIACROM S PATU LA

Manufactured in France British Patents applied for

No other cleaner has all these advantages: - 1. Only 100% pure. natural diamond grans are utilised

2. Blades are treated with hard chrome to reinforce the setting of the diamond grains. to obviate loosening or breakaway during use. This process also prevents clogging of the diamonded surface by residues resulting from use 3. All diamonded blades are rectified to ensure an absolutely smooth surface by eliminating diamond grains which may rise above the surface. This eliminates all excessive scratching during use. The Microvalue Group dealers shown

4. All diamond grains are rigidly calibrated to ensure a perfectly uniform grain size of either below represent part of the Gemini network. 200. 300 or 400. For expert advice and full details on the friction the rigidity of the nylon handle id S. The chrome gives a very weak co -efficient of and Gemini System, contact your nearest dealer calculated to permit proper utilisation and yet pliant enough to avoid undue pressures on highly delicate relays. today. Grain size 200 thickness 55/100 mm both faces diamonded. For quick cleaning of industrial switching equipment. etc. relays and LTD Grain size 300. thickness 55/100mm. both faces diamonded. For smaller equipments. like, AMERSHAM COMPUTER CENTRE telephone relays. computer relays. etc. 18 Woodside Road, Amersham, Bucks HP7 OBH 25;100 mm.. one face diamonded. For sensitive relays and tiny Grain size 400. thickness Tel: Telex: contacts. Two close contacts facing each other can be individually cleaned. because only one 02403 22307 837788 face of the spatula is abrasive. Sole Distributors for the United Kingdom BUSINESS & LEISURE LTD SPECIAL PRODUCTS (DISTRIBUTORS) LTD 16 The Square, Kenilworth, Warwickshire CV8 1 ED 81 Piccadilly, London W1V OHL. Phone: 01-629 9556 Tel: 0926 512127 As supplied to the M.O.D., U.K.A.EA., C.E.G.B. British Rail end other Public Authorities; also major industrial and electronic users throughout the United Kingdom. CENTIFLEX MICROSYSTEMS LTD CIRCLE 70 FOR FURTHER DETAILS. Unit 6, Perry Road, Staple Tye, Harlow, Essex CM18 7NW Tel: 0279 442233 Marconi A.F. wattmeter CT44, 200 microwatts to 6 watts in 10 ranges switched - 2150 ohms. £30. P&P paid. Marconi H.F. wattmeter CT211, high power 70 ohms 25 ELECTROVALUE LTD watts, low power 52 ohms, 1 watt. £25. P&P paid. Ex -Gov. 27ft telescopic aerial close to 5ft. Good condition, complete with all base & fittings £45. P&P paid. Callers 28 St. Judes Road, Englefield Green, Egham, welcome £25. Pye Pocketfone Nightcall for PF1/TX/RX. New boxed £17.00. Whip Surrey TW20 OHB aerial Ex -Gov. 4ft collapsible £1.00. Steel 2 in. Interlocking Mast sections 4ft. Price Tel: 07843 3603 Telex: 264475 f4 each p&p paid min. 5. Crystals HC6U Ex. Equip. 5,000 mc/s, 7.000 mc/s, 8.000 I.M.C. mc/s, 9.000 mc/s. Also Glass Crystal 100 Kc/s, to fit B7G base. All at £3 p&p Marconi. A.M. Signal Generator CT 452A 10 kc/s to 72MC/S £100 p.p paid. paid. E.V. COMPUTING Fibre - Glass Aerial Sections 3ft x 1'/,in dia. Push in type £2.50 per section min 5 pip. paid. 700 Burnage Lane, Manchester M19 1 NA Airlite 62 headsets boom mike 300 ohms as new £20 p.p. paid. Ni -Cad batteries for Tel: 061-431 4866 Pye PF1 RX. 5 for £2 p&p paid. Min. order 5. All these batteries are ex-eq. but good condition. Bargain Parcels 14 lbs at £10, 28 lbs at £20 and 56 lbs at £40, p&p paid. Contains pots, res., diodes, tagboards, caps., chassis, valve holders etc. Good value HENRYS RADIO save £ £ £'s. Lucky dip service. AVO 7X. Tested. Ex. eq. £40 p&p paid. 404 Edgware Road, London W2 Opening times: Monday -Friday 8.30am-5.00pm, Saturday 8.30am-12noon Tel: 01-402 6822

Please allow 14 days for delivery. Mainland only. LEEDS COMPUTER CENTRE A. H. THACKER & SONS LTD 55 Wade Lane, Merrion Centre, Leeds LS2 8NG HIGH STREET, CHESLYN HAY NEAR WALSALL, STAFFS. Tel: 0532 458877 CIRCLE 53 FOR FUR'T'HER DETAILS. OFF RECORDS LTD Computer House, 58 Battersea Rise, 68000 SYSTEM Clapham Junction, London SW 11 I HH Andelos Tel: 01-223 7730 Powerful 6800 runs at 10MHz without wait states. Up to 32KB EPROM and 4 or 16KB fast static RAM. 24 line SKYTRONICS LTD programmable parallel I/O port. RS232 programmable 357 Derby Road, Nottingham NG7 2DZ serial port. Comprehensive monitor in 2764 Eproms. Tel: 0602 781742 Optional plug-in Eprom programmer card. Cross for Z80 based microcomputers. Code can NEWBURN ELECTRONICS LTD Assemblers 58 Manse Road, Ballycarry, Carrickfergus, be developed, downline loaded to 68000, debugged, N. Ireland BT38 9LF and then written into Eprom. Tel: 09603 78330 10MHz 68000 CPU Board from £295+VAT * EPROM PROGRAMMER card £95+VAT * CROSS ASSEMBLER for Z80 hosts... from£55+VAT Andelos Systems Telephone: (0635) 201150 Solina, Buckley Alley, Cold Ash, Newbury, Berkshire RG16 9NN CIRCLE 62 FOR FURTHER DETAILS. 1984 10 ELECTRONICS & WIRELESS WORLD DECEMBER

www.americanradiohistory.com Every card's a winner. The vers 80 -Bus system can be used for a host of applications: Process Con Batch Counting, Robotics, Colour Graphic Displays, CAD/CAM, CN In Manufacturing, Telecommunications Instrumentation, Laboratory Testing, Security Systems, Plant Control, Data Collection and Distribution. Also, in smaller companies it can handle Acc punts, Payroll, Wordprocessing, Stock Control, Program Compilation and Data Base Management... whilst still being able to run specialist applications. And because there is no wasted capacity -Nith a Gemini, a system can cost a good deal less than you might think. With Gemini you can buy a complete system, upgrade your existing 80 -Bus system, or build your own. So when you've had a look at the pack of cc rds below, plug yourself into our dealer network to c iscover

how opening a new pack of cards with Gemir i will help ypu pick a laix ,.

These represent just a small selection from the -ar ge of over 25 cards.

GM813 CPU/64K RAM BOARD - This card provides system 4 GM837 COLOUR GRAPHICS BOARD - 256 x 256 sixteen MHz, Z80 CPU, 64K user RAM and both serial and parallel I/O. colour graphics display. Output to either PAL UHF or RGB. GM811 CPU BOARD - An industrial standard 4 MHz, Z80 GM816 MULTI I/O BOARD - Provides three Z80A PIO devices controller board with parallel and serial I/O together with a plus CTC and battery backed Real Time Clock. variable Bytewide memory capacity. GM848 SERIAL I/O BOARD - Utilises two Z80A SIO chips GM888 CPU BOARD -A new card featuring the Intel 8088 providing four synchronous/asynchronous serial channels with processor to provide a dual processor system. software selectable baud rates. GM832 SVC BOARD - Provides conventional 80 x 25 or 40 x 25 GM836 NETWORK INTERFACE BOARD - Provides RS422 screen format together with graphics capability. Includes full communication protocol for networking CPU boards. keyboard support and overseas character sets. GM862 256K RAM BOARD - Supports both page mode and extended addressing facilities and can be used with all of the Gemini CPU cards. GM833 512K RAM-DISK BOARD - Provides 'psuedo disk' facility in a MultiBoard system. GM829 FDC/SASI BOARD - Combines floppy disk controller and SASI board supports up to four floppy disk drives pus Winchester controller cards. The dealer's choice

Gemini Microcomputers Ltd., 18 Woodside Road, Amershom, Bucks, England HP6 OBH. Tel: (02403) 28321. Telex: 837788

CIRCLE 46 FOR FURTHER DETAILS.

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 11

www.americanradiohistory.com 132 COLOuRIET 132 Column Compressed Mode PRINTER. I I INK JET Cash price 36 COLOUR £499 + VAT Logic seeking in Centronics parallel interface with dot address mode full Viewdata and free BBC Micro dump listing. also: prints OVERHEAD TRANSPARENCIES Options available Buffered RS232/Viewdata interface Apple II & IIe interface IBM pc dump Specifications: 1280 dots/line in double res. mode 37cps in full colour Friction feed roll paper and single sheet feed A4 Ink cartridges 4 million character life Portwood Industrial Estate, Church Gresley Burton -on -Trent, Staffs DE11 9PT ,. ,,.,.. INTEGREX LIMITED Burton -on -Trent (0283) 215432. Telex: 377106

(' DIX' I.I:11 FOtt R1'III:RDETAILS. 1.5GHz testing problems? Sowter Transformers With 40 years" experience in the design and manufacture of several hundred thousand transformers we can supply . _, AUDIO FREQUENCY _ e .. .rllt,. TRANSFORMERS OF EVERY TYPE YOU NAME IT! WE MAKE IT! OUR RANGE INCLUDES Microphone transformers tall types), Microphone Splitter/Combiner transfor. mers. Input and Output transformers, Direct Injection transformers for Guitars. Multi -Secondary output transformers, Bridging transformers. Line transformers. Line transformers to G.P.O. Isolating Test Specification, Tapped impedance matching transformers, Gramophone Pickup transformers, Audio Mixing Desk Use a TECHTEST Model 260 transformers (all types), Miniature transformers, Microminiature transformers for PCB mounting, Experimental transformers, Ultra low frequency transformers, Ultra linear and other transformers for Transistor and Valve Amplifiers up to 500 1.5GHz Up -Converter watts. Inductive Loop Transformers, Smoothing Chokes, Filter. Inductors, Ampli- fier to 100 volt line transformers (from a few watts up to 1,000 watts), 100 volt line transformers to speakers, Speaker matching transformers (all powers). Column it works with any 240-350 MHz generator Loudspeaker transformers up to 300 watts or more. - We can design for RECORDING QUALITY. STUDIO QUALITY, HI-FI QUALITY OR P.A. QUALITY. OUR PRICES ARE HIGHLY COMPETITIVE AND WE SUPPLY LARGE The Model 260 has been designed to provide a very OR SMALL QUANTITIES AND EVEN SINGLE TRANSFORMERS. Many standard 1.5 GHz communication types are in stock and normal dispatch times are short and sensible. economical signal source for testing OUR CLIENTS COVER A LARGE NUMBER OF BROADCASTING AUTHORITIES, equipment. It is a linear heterodyne up -converter that employs MIXING DESK MANUFACTURERS, RECORDING STUDIOS, HI-FI ENTHUSIASTS. BAND GROUPS, AND PUBLIC ADDRESS FIRMS. Export is a speciality and we advanced techniques to generate very clean and stable signals have overseas clients in the COMMONWEALTH, E.E.C., USA, MIDDLE EAST, etc. generator inputs 1200 Send for our questionnaire which, when completed, enables us to post quota- in the 1440-1550 MHz band from signal tions by return. MHz lower. Since it has zero insertion loss the input signal generator controls are used directly to set the output signal level and all modulation conditions. Full accuracy and stability 1200 MHz local A. Ltd. is ensured by phase -locking the internal E. Sowter oscillator to the signal generator standard. Find out more from: Manufacturan and Designers E. A. SOWTER LTD. (Established 1941) : Reg. No. England 303990 The Boat Yard, Cullinghan, Road, Ipswich IP1 2EG, Suffolk Leominister, P.O. Boa 36, Ipswich, IP1 2EL, England Techtest Ltd, Street Court, Kingsland, Phone: 0473 52794 and 0473 219390 Herefordshire HR6 9QA England. Telex 987703G Sowter Telephone: KINGSLAND (056881) 744 Telex 837264. CIRCLE 33 FOR FURTHER DETAILS. CIRCLE 35 FOR FURTHER DE'T'AILS.

12 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

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B111257 0.27 GEX541 5.00 0AZ207 1.50 OC205 2.75 ZTX504 0.21 2N1671 5.00 2N3819 0.30 SEMICONDUCTORS BD132 0.48 5F258 0.27 GJ3M 1.50 OC16 2.50 0C206 2.75 Z11(531 0.24 2N1893 0.32 2N3820 0.39 ASZIS 1.20 BC173 0.11 AA119 0.10 BD135 0.10 5F259 0.28 GM0378A 1.75 0C20 2.50 2.50 ZTX550 0.25 2N2147 4.00 2N3823 0.60 ASZ16 1.10 0.28 0C207 MY30 0.17 BC077 5D136 0.40 BF336 0.34 KS100A 0.45 0C22 2.50 OCP71 2.00 IN914 0.05 2N2148 3.75 2N3866 1.00 A0Z17 1.00 5C178 0.28 AAY30 0.17 BD137 0.40 BF337 0.33 MJE340 0.60 0C23 4.00 ORPI2 1.00 154916 0.09 2N2218 0.32 2N3904 0.17 ASZ20 2.30 BC179 0.28 AAZ13 0.15 BD138 0.48 BF338 0.36 MJE370 0.73 0C24 3.00 112008B 2.00 1N4001 0.06 2N2219 0.32 2N3905 0.17 AAZ15 0.15 ASZ2I 2.50 BC182 0.11 2N2220 0.20 0.17 250 BD139 0.48 5F521 4.00 MJE371 0.71 0C25 1.00 R2009 2.25 IN4002 0.06 2N3906 AAZI7 0.15 413113 BC183 0.11 BD140 0.50 BFS28 2.25 MJE520 0.17 0C26 1.50 R20105 2.00 IN4003 0.06 2N2221 0.20 2N4058 0.20 AUY10 3.00 0.11 AC107 0.55 5C184 BD144 2.00 BFS61 0.20 M)E521 0.73 0C28 2.00 T1C44 0.27 1544004 0.07 2N2222 0.20 2N4059 0.20 AC125 0.25 BAI45 0.13 BC212 0.11 BD181 1.20 5F398 0.20 MJE2955 1.30 0C29 2.00 T1C226D 1.20 1N4005 0.09 2N2223 4.25 2N4060 0.16 ACI26 0.25 BA148 0.15 BC213 0.11 BDI83 0.80 BFWIO 0.97 M E3055 1.10 0C35 1.50 T1L209 0.16 1N4006 0.11 2N2368 0.25 2N4061 0.16 ACI27 0.25 BA154 0.10 BC214 0.11 502137 0.54 BFWII 0.96 MPFI02 0.35 0C36 1.50 T1P29A 0.43 IN4007 0.12 2N2369A 0.25 2N4062 0.16 AC128 0.30 BA155 0.11 BC237 0.11 5D238 0.54 BF3(84 0.30 MPF103 0.35 0C41 0.90 TIP30A 0.45 IN4009 0.07 2N2484 0.25 2N4124 0.16 0.11 AC141 0.28 BA156 0.10 BC238 BDX10 0.91 BFX85 0.30 MPF104 0.35 0C42 0.90 TIP31A 0.33 IN4148 0.04 2N2646 0.50 2244126 0.16 AC141K 0.35 BAW62 0.05 BC301 0.33 BDX32 2.00 'BFX87 0.30 MPF105 0.35 0C43 1.50 TIP32A 0.36 IN5400 0.13 2N2904 0.32 2N4286 0.15 AC142 0.28 BAXI3 0.06 BC303 0.34 BDY20 1.50 BFX88 0.30 MPSA06 0.26 0C44 0.85 T1P33A 0.54 1N5401 0.13 2N2905 0.32 2N4288 0.18 0125(60 ACI42K 0.35 BAXI6 0.06 BC307 0.11 2.75 BFY50 0.25 MPSA56 0.28 0C45 0.65 T1P34A 0.67 1S44 0.04 2N2906 0.21 2N4289 0.18 AC176 0.30 BC107 0.16 BC308 0.11 BF115 0.15 BFY5I 0.25 MPSUOI 0.53 0071 0.55 TIP41A 0.44 15920 0.08 2242907 0.21 2N4400 0.11 0.12 AC187 0.28 BC108 0.16 BC327 BFI52 0.16 BFY52 0.25 MPSUO6 0.65 0072 1.00 T1P42A 0.02 15921 0.09 2N2924 0.26 2N4401 0.11 BC328 0.12 AC188 0.28 BC109 0.16 BFI53 0.16 BFY64 0.30 MPSU56 0.69 0073 1.00 T1P2955 0.70 2G301 1.00 2N2925 0.22 2N4402 0.11 ACYI7 1.30 BCII3 0.15 BC337 0.12 BF154 0.17 BFY90 0.95 NE555 0.45 0074 0.70 T1P3055 0.56 20302 1.00 2N2926 0.15 2N5457 0.32 0.12 ACY113 1.15 BCII4 0.15 BC338 8F159 0.17 BSX19 0.27 NKT401 3.50 0075 0.65 T1S43 0.43 2G306 1.00 2N3053 0.26 2N5458 0.32 1.25 ACYI9 1.10 BC115 0.18 BCY30 BF160 0.17 BSX20 0.27 NKT403 2.50 0076 1.00 ZS140 0.25 2N404 1.30 2N3054 0.55 2245459 0.32 BCY31 1.50 ACY20 1.10 BCI16 0.19 5F167 0.24 BSX21 0.29 NKT404 2.20 0077 1.00 ZSI70 0.21 2N6% 0.32 2N3055 0.65 25017 10.00 BCY32 1.50 ACY21 1.15 BC117 0.23 5F173 0.30 BT106 1.20 OAS 1.20 0081 0.65 ZS178 0.54 2N697 0.32 2143440 0.70 2S019 12.00 ACY39 2.50 BC118 0.18 BCY33 1.10 BF177 0.35 BTY79/4R 0A7 0.60 00812 1.20 ZS271 0.23 2N698 0.32 2N3441 0.85 25.00 AD149 0.75 BC125 0.18 BCY34 1.00 BF178 0.35 2.00 0A10 0.55 0082 0.90 ZS278 0.57 2N705 1.25 2N3442 1.25 25103 1.50 AD161 0.35 BC126 0.18 BCY39 3.40 5E179 0.35 BU205 1.30 0A47 0.12 OC83 1.00 ZTX107 0.12 2N706 0.25 2N3614 2.20 25302 3.50 BC135 0.15 BCY40 2.80 0025026 AD162 0.35 5F180 0.28 B1J206 1.50 0A70 0.25 0084 0.80 ZTX108 0.12 2N708 0.25 2543702 0.11 25303 1.50 0.30 AF106 0.35 BC136 0.19 BCY42 BF181 0.28 BU208 2.00 0A79 0.12 0C122 2.75 27X109 0.12 2N930 0.25 2N3703 0.11 2S322 3.50 0.19 BCY43 0.30 AF114 3.50 BC137 5E182 0.30 BY100 0.40 OAS] 0.17 0C123 2.00 ZTX300 0.13 2541131 0.30 2N3704 0.11 2S324 3.50 0.19 AF115 3.50 BC147 0.12 00(58 BF183 0.28 BY126 0.13 0A85 0.17 0C139 3.00 ZTX301 0.11 2N1132 0.30 2N3705 0.11 2S701 3.50 AF116 3.50 BC148 0.12 BCY70 0.17 8F184 0.28 BY127 0.14 0A90 0.08 OC140 4.00 ZTX302 0.18 2N1302 1.20 2N3706 0.11 25745A 0.95 AF117 3.50 BC119 0.13 BCY71 0.18 BF185 0.30 BZX61 0.17 0A91 0.08 0C141 4.25 211(303 0.18 2N1303 0.80 2N3707 0.11 2S746A 0.95 BCY72 0.17 AFI39 0.33 BC157 0.13 BF194 0.14 Series 0A95 0.08 0C170 4.50 Z71(304 0.20 2241304 1.20 1543708 0.10 AFI86 1.00 BCI56 0.13 BCZII 1.75 BF195 0.12 BZY88 0.10 0A200 0.15 0C171 4.50 ZTX3I1 0.13 1.00 2543709 0.11 0.03 2N1305 AF239 0.39 BC159 0.13 BD115 0.42 BF1% Series 0A202 0.15 0C200 1.50 ZTX311 0.25 2N1306 1.50 2N3710 0.10 CV Devices AFZII 4.00 BC167 0.11 BD121 1.70 BFI97 0.14 CRS140 0.60 0A211 1.50 0C201 2.50 ZTX500 0.14 2N1307 1.10 2N3711 0.10 Large stocks AFZ12 4.00 5C170 0.11 5D123 2.80 8F200 0.40 CR53740 0.75 OAZ200 1.50 0C202 2.75 ZTX501 0.14 2N1308 1.75 2N3771 1.40 Prices on ASY26 1.40 BC171 0.11 BD124 2.00 5F224 0.25 CRS3/60 0.90 OAZ201 1.50 0C203 3.00 ZTX502 0.18 2N1309 1.20 2N3772 1.60 application ASY27 0.90 BC172 0.11 BD131 0.44 BF244 35p 0EX66 3.00 0AZ206 1.50 0C204 3.00 21X503 .19 jj7613 0,32, 2N3773 1.80 r 1 2. 00 00.00 2.56 I2AX7 1.75 9.00 EI3OL 18.50 EF85 1.75 GXUI 15.35 OD3 2.50 0Y365 63.24 UF4 4-250A 6C07 5642 3-50 2.10 13.66 I2AY7A 4.00 3.00 VALVES EI80CC 10.50 EF86 GXU2 30.00 024 3.50 0Y3 125 68.64 UF42 4-400A 87.00 6CH6 5654 70.04 UF80 1.75 6CL6 3.75 1254A 3.50 5651 4.15 A1834 9.00 E18OF 10.20 EF89 2.50 GXU3 25.40 PC86 2.50 QY4.250 4832 20.00 1.75 125A6 2.50 A2087 13.50 E182CC 13.25 EF91 2.95 OXU4 44.50 PC.88 2.006 0Y4-400 76.20 UFOS 4C35 78.00 6CW4 8.00 5670 4.50 A2134 17.50 E186F 11.50 EF92 6.37 GXU50 20.00 PC95 1.75 QY5-5i0i 190.00 UF89 2.00 4CX250B 45.00 602 1.50 128E6 2.50 5675 28.00 A2293 16.00 E188CC 8.91 EF93 130 GY501 3.00 PC97 1.75 QY5-3000A UL41 5.00 4CX350A 80.00 6DK6 3.00 12BH7 2.75 5687 6.00 A2426 27.50 E280F 22.51 EF94 2.50 GZ32 4.00 PC900 1.75 450.00 UL84 1.75 4X150A 60.00 6DQ6B 4.75 12BY7 3.00 5696 4.50 A2521 25.00 E263CC 12.00 EF95 5.99 GZ33 4.75 PCC84 1.50 QZ06-20 32.70 ÚM80 2.00 4X1500 56.00 6EA8 3.00 12E1 20.00 5718 7.50 A2900 15.00 E288CC 17.50 EF98 2.00 GZ34 3.00 PCC85 1.50 RIO 6.00 UY41 2.25 56254M 35.00 6E58 2.50 12E1 ITT 28.00 5725 5.50 A3343 15.00 EA52 125.00 EF183 2.00 0Z37 1.75 PCC88 2.00 RI7 3.00 UY85 2.25 58255M 35.00 6EW6 2.25 12E14 65.00 5726 11.37 AZ31 2.75 EA76 2.50 EF184 2.00 KT61 5.00 PCC89 1.75 RI8 3.00 VLS631 15.00 5C22 160.00 6F6 3.00 IJEI 170.00 5727 7.05 19114 27.50 AZ41 2.60 EABC80 1.25 EF804S 12.00 KT66 15.00 PCCI89. 2.50 RI9 9.24 XG1-2500 55.00 55180E 1650.00 6F23 1.60 5749 2.50 0.60 19H5 17.50 111(448 114.90 EAC9I 3.50 EF8055 15.00 KT77 Gold PCC805 1.60 K20 2.50 XG2-6400 5R4GY 3.50 6F28 5751 4.00 2409 67.25 BK484 155.35 EAF42 2.50 E0590 1.75 Lion 12.00 PCC806 1.60 RG3-250 32.68 141.90 5U40 3.00 6F33 33.50 5763 4.50 BS90 58.00 EAF801 2.00 EK% 1.50 KT88 Gold PCE82 2.00 R03 -250A 32.68 XG5-500 26.60 5U10B 2.50 6H1 14.00 30C15 2.00 5811A 4.00 30C17 2.00 BS810 60.00 EB41 4.00 EL32 2.50 lion 20.00 PCF80 2.00 RG3-1250 59.50 XG245400 5V40 2.50 6H2N 2.75 5840 4.00 1.50 EL33 4.00 PCF82 1.50 5Y3GT 2.50 6H3N 2.75 30C18 2.00 5842 12.00 BT5 58.95 EB9I KTW6I 2.50 RG4-1250 61.60 162.00 EBC33 2.50 EL34MUI 4.00 PCF86 2.50 4.00 3.00 30F5 1.60 5876A 31.50 0117 151.00 KTW62 2.50 RG4-3000 99.45 XRI-1600A 5Z3 6H6 44.05 EBC41 2.50 EL36 2.50 PCF87 2.00 2.50 654 5.50 30FL1/2 1.38 5879 5.00 0319 KTW63 2.50 RR3-250 40.00 53.75 5240 EBC81 1.50 EUI 2.80 PCF200 3.25 2.50 656 8.93 30FL12 1.80 5886 17.50 0129 349.15 M8079 12.34 RR3-1250 45.75 XR1-3200 81.97 5Z401 EBC90 1.25 EL42 2.50 PCF201 3.25 511E12 65.00 6-30L2 1.75 637 4.75 30FL14 2.00 5963 2.50 BT69 354.80 M8080 0.25 XRI-3200A 1 EBF00 EL81 5.25 PCF801 2.50 30L1 1.50 5965 3.50 BT95 19.90 I.50 MBOBI 9.82 5130 600 XRI4S400 6AB4 1.75 6K4N 2.50 EBF83 1.75 EL83 6.00 PCF801 2.50 5130P 6.00 165.00 6.057 3.00 6K6GT 2.75 30LI5 2 00 6005 2.25 CBL3I 4.00 M8082 9.69 EBF89 1.50 EL84 2.25 PCF605 1.70 STV280-40 395.00 6AC7 3.00 60(7 3.00 30L17 2.00 6021 1.50 CL33 1.00 M80ß3 0'58 YD1120 EBL3I 10.00 EL86 2.75 PCF806 1.70 14.00 YD1240 d90.W 6AF4A 4.25 3.00 30P4 2.50 6057 10.23 CY31 10.43 6K8 3.00M6091EC90 1.25 EL% 2.25 PCF800 1.70 STV280.80 Z759 25.00 6AG7 3.00 6KD6 1.00 30P19 2.50 6058 12.31 CIK 20.00 M80% 6.807 30PL1 3.00 C3A 22.00 F.C91 8.00 EL91 9.69PCL82 2.00 21.00 ZM1000 B.00 6AH6 5.00 6L6G 3.00 6059 6.00 8.10 EC92 1.75 EL95 2.00 PCL83 3.00 SU41 5.00 8.00 6AK5 5.99 3.00 30PL14 1.80 6061 6.00 C3JA 22.00 MOU98 8.15 ZMI001 6L60A EC157 410.00 EL156 30.00 PCL84 2.00 SU42 10.00 9.00 6AK6 2.50 3.50 30PLI5 1.80 6063 3.75 DA4I 25.00 M8099 8.00 ZMI020 6L6GC ECC33 4.50 EL360 B.SO 2.50 TD03-10 35.00 ZM1021 9.00 6AL5 1.50 3.00 35W4 1.00 6064 6,58 DA42 18.70 M8100 9.52 IL85 6L6GT DAF9I 1.75 ECC35 4.50 EL500/504 3,00 PCL86 2.50 TD03-10F 35.00 ZM1022 9.00 6AM4 4.00 6L7 2.50 5005 1.50 6067 10.23 ECC40 4.50 EL509 7.00 PCL005/85 2.50 TTIS 50.00 9.00 6AM5 9.69 6N2P 2.50 6.05 6072 6.00 DAF% M8137 10.23 ZMI°23 1.75M8136ECC81 1.75 EL821 13.00 PD500 6.00 TT21 30.00 ZMI040 19.36 6AM6 6.02 6N3P 2.50 75CI 4.50 6080 14.00 DET22 35.00 M8140 10.2375816.00 ECC82 1.75 EL822 13.97 PE06-4]24 45.00 37.50 16.66 6ÁN5 1.75 6N7 3.00 85A1 7.50 6097A 235.00 DET24 49.00 M8141 6.50 Tf22 ZMI011 ECC83 1.75 EM34 5.00 PFL200 2.50 TT100 60.00 ZM1042 17.77 6AN8A 3.50 6P25 4.00 85A2 6.45 6097B 200.00 DF91 1.75 M8142 8.75 ECC84 1.75 EMBO 2.50 PL36 2.50 TY2-125 65.00 15301 3.00 6AQ5 2.25 6Q7 3.75 90AG 12.96 6146A 8.25 0F% 1.75 M8144 7.50 ECC85 1.75 EMBI 2.50 PL81 1.75 TY4-400 8000 1524 25.00 6AS6 8.66 6R7 3.25 90AV 12.% 61468 8.25 00(91 1.75 M8119 6.50 ECC86 2.50 EM84 2.00 PL81A 2.00 TY4-500105.00 1535A 18.00 6AS70 8.75 6SA7 3.00 90CI 6.00 615913 19.00 00(92 2.00 M8161 9.35 ECC88 2.10 EM85 2.75 PL82 1.50 TY5-500214.00 1B63 64.00 6AT6 1.25 6SC7 2.75 14.51 6189 9.50 DK% 1.75 M8162 10.10 9 2.00 ECC89 2.00 EM87 2.50 PL83 2.50 TY6-800 210.00 IRS 1.75 6AU5GT 5.00 65F7 2.50 90CV 15.45 6201 11.10 DL92 M8163 8.25 92AG 20.00 6442 DL94 1.75 ECC9I 8.93 E5432 17.16 PL84 2.00 TY6.S000A 1S5 1.75 6AU6 2.50 60057 3.00 20.00 ECC169 2.10 EN91 6.50 M°I% 5.00 PL5045 2.50 490.00 1.75 6AV5GA 4.50 6SI7 3.25 92ÁV 20.00 68838 8.25 DL96 1.75 Mß195 00.85 114 ECC807 1.75 EN92 6.96 PL508 2.50 TY6-50008 11.50 , 6AV6 1.S0 3.50 %A1 8.45 6973 4.00 DLSIO 14.00 M81% 2AS15 6SK7 3.00 EY51 2.75 PL509 6.00 395.00 2C39A 60.00 6AXSGT 3.00 6SK7GT 3.00 6.50 7025 3.00 DLSI5 12.50 ECC008 M8201 7.05 ECF80 1.55 EY81 2.50 PL519 6.00 TY6-5000W 2C43 70.00 667 3.25 6SN7GT 3.00 15083 8.35 7551 6.25 DLSI6 12.50 M8212 11.377.5015082 ECF82 1.50 EY83 2.50 PL801 1.50 42500 3.25 6B8 3.25 3.40 150C2 3.25 7586 15.00 DLS19 12.50 M8223 6.00 2021 6SQ7 ECF86 2.50 EY64 9.24 PL002 6.00 TY7-6000A 8.25 6BA6 1.50 /.00 150C4 6.00 7587 23.00 DM70 2.00 M8224 6.30 2E26 6SR7 136171 ECH35 3.00 EY86 1.75 PY33 2.50 525.00 2342 98.00 6BA7 5.00 6557 2.75 211 35.00 7609 56.00 2.00 M8225 4.50 DM160 /.75 ECH42 3.50 E1'88 1,75 PY81 1.50 1Y7-600080 2555 175.00 6BA8A 4.00 6U50 3.50 723AB 125.00 7868 6.00 ..8248 11.03 25.00 DY87 1.50 ECH81 3.00 EY500A 300 PY82 1.50 525.00 2570A 383.00 6BC4 4.00 6U8A 2.25 003 7895 12.00 MD2901 115.00 45.00 1.50 ECH83 2.50 EY802 1.75 PY83 2.50 1Z40 25.00 2 705 336.00 6BE6 1.50 6V6GT 2.25 005 8005 110.49 01802 MU 4 2.50 45.00 ECH84 2.50 EZ35 1.75 PY88 2.00 U18-20 3.50 2K25 125.00 6BH6 2.50 6X4 2.00 007 3.75 8068 14.00 E55L 2 19 55.00 ECL80 1.50 EZ40 2.50 PY500A 4.00 U19 13.75 3-/002 85.00 6B56 2.25 6X5GT 1.75 811.0 18.33 8122 90.00 E8OCC 8.81 MX 23 72.00 ECL81 1.75 EZ41 2.50 PY800 1.50 U25 2.50 3-500Z 85.00 68K4 1.50 757 2.50 812A 29.50 8136 2.50 EBOCF 11.27 MX 45 56,70 ECL82 1,S0 EZ80 1.50 PY001 1.50 U26 2.50 3A5 3.00 6BL6 85.00 7C5 4.00 813 125.00 8417 6.00 E00F 14.19 MX 51 17.25 E80L 13.73 ECL83 3.00 EZBI 1.50 QF451 82.50 U37 12.00 3824 11.00 6BL7GT 1.50 7C6 2.50 033A 193.16 18042 11.53 MX 52 131.25 866A 20.03 E81CC 8.00 ECL84 1,50 EZ90 2.00 Q0V02-6 31.80 UABC80 1.25 3528 15.35 68M6 115.00 7H7 4.00 18045 10.49 MX 61 152.25 4,25 872A 20.00 E81L 13.27 ECL85 1.50 F7074-500 3.50 Q3-1023,50QC/W(3-1023.50MX UAF42 2.50 3529 20.05 6BN6 2.00 7R7 63 20.25 922 6.00 35.48 ECL86 1.75 FW4-600 3.50 74.7. QQV03-20A UB41 3.00 35240M 17.50 6807A 3.50 757 3.50 Trued E810F 64 25.52 E82CC 8.10 EF37A 5.00 G1.371K 35.00 48.38 UBC41 2.25 35241M 17.50 68R7 6.00 7Y4 2.25 931A 18.50 Ex-Equipmxnt auk 66 147.00 E83CC 8.40 EF39 2.75 GSSIK 12.00 QQV06-40A UBF89 1.50 3C23 25.00 6BR8A 3.54 7Z4 2.00 1624 1.00 4CX2505 6.50 68 50.00 E86C 0.25 EF40 5.00 0100.234 17.50 MX ,75.00 1JCC84 1.75 3C45 20.50 6857 6.00 11E3 55.00 1625 3.50 CV Devices E88C 8.25 EF41 3.50 0240.20 12.00 03; QQV07-50 69.74 UCC85 1.85 3CX100A5 65W6 6.00 12A118 5.00 2050 7.50 Large stocks 1.50 NO QQZ066-40A UCF80 2.00 47.00 613W7 1.50 1.50 4212E 300.00 Prices on E88C 8.12 EF42 0400.1K 17.50 0A3 2.50 I2AT6 EF50 2.50 9.00 75.00 UCH42 2.50 3E29 45.00 6BX7GT 5.00 12A17 1.75 55142411 300.000 application E9OCC 9.47 GN4 0A4 6.00 9.90 EF54 5.00 GN4A 9.00 QV37 12.50 00H81 2.50 3S4 2.00 68Z6 2.75 12AU6 2.50 E%F OB2 435 EF55 3.50 GS16 16.00 Q 03-12 6.80 UCL82 1.75 3V4 1.75 6C4 1.25 12AU7 1.75 5515 145.06 E91H 6.25 OB3 2.50 E92CC 8.75 ERA 1.75 GT1C 15.00 QV047 3.50 UCL83 2.75 465A 60.00 6036A 2.58 12AV6 2.50 5551A 114.90 9.10 EF83 4.00 20.00 0V08-100171.20 4-125.0 60.00 5.00 12AV7 3.50 E99F GUSO OC3 Ì.SÓ 6CD6GA 5552A 155.35 GU51 20.00 7495 0.73 74136 0.51 74175 1.02 TBA520Q 2.30 INTEGRATED CIRCUITS 7496 0.82 74141 0.89 74176 1.16 TBA530 1.98 7400 0.16 7423 0.33 7460 0.18 7497 3.15 74142 2.30 74178 1.36 TBA540Q 2.30 SADPI 55 00 VCR517B 10.00 7401 0.17 7425 0.30 7470 0.38 74100 1.54 71143 2.60 74179 1.36 TBASSOQ 3.22 BASES CRTs SCPI 10.00 VCR517C 10.00 7402 0.17 7427 0.30 7472 0.33 74107 0.4S 74144 2.60 74180 1.20 TBA560CQ 3.22 2AP1 8.50 r5CP1A 40.00 7403 0.17 7428 0.43 7473 0.38 74109 0.73 74145 1.00 74190 1.90 TBA673 2.20 213P1 9.00 137Gunskirted 0.25 SFPISA 15.00 7404 0.18 7430 0.17 7474 0.38 74110 0.51 74147 2.00 74191 1.90 TBA700 1.52 3BP1 12.00 B7Gskined 0.35 5UP7 25.00 7405 0.18 7432 0.30 7475 0.54 74111 0.71 74148 1.76 74192 1.90 TBA720Q 2.30 3DP1 5.00 B9A unskined 0.25 007.5 63.32 7406 0.43 7433 0.40 7476 0.42 74116 1.85 74150 1.80 74193 1.90 TBA750Q 2.07 3EG1 10.00 B9A skinad 0.35 007-31 58.07 Tube Bases 7407 0.43 7437 0.32 7480 0.56 74118 1.00 74151 0.94 74194 1.25 TBA800 1.20 3FP7 6.00 lot Octal 0.35 007-32 58.07 Prices on 7408 0.20 7438 0.32 7482 0.75 74119 1.54 74154 1.80 74195 1.20 TBA920 2.90 3GPI 6.00 Long0.55 DG7-36 65.00 application 7409 0.20 7440 0.32 7483 1.00 74120 0.83 74155 0.90 74196 1.35 TBA920Q 2.90 3JP1 0.00 Nuvistorlsºse 2.00 0053-91 56.83 7410 0.17 7441 0.90 7484 1.05 74121 0.43 74156 0.90 74197 1.35 TBA990Q 2.90 3JP2 0.00 8 pm DIL Texas 0.10 DH7-11 113.12 7412 0.29 7442 0.72 7486 0.39 74122 0.62 74157 0.75 74198 2.70 TCA270Q 2.90 14 pin Texas 0.10 31P7 10.00 DIL VCR97 12.00 7413 0.32 7447AN 1.17 7490 0.60 74123 1.18 74159 2.10 74199 2.30 TCA760A 1.38 3KP1 15.00 16 pm OIL Team 0.10 VCR138 12.00 7416 0.32 7450 0.18 7491 0.82 74125 0.58 74170 2.40 TAA570 2.30 Valve 35.00 screening 3RPI VCR 138A 12.50 7417 0.32 7451 0.18 7492 0.60 74126 0.58 74172 4.40 TM630S 3.50 3WPI 20.00 ...II 1.66 0.40 VCR139A 800 7420 0.18 7453 0.18 7493 0.60 74128 0.63 74173 1.42 TM700 3.90 7422 0.20 7454 0.18 7494 0.02 74132 0.72 74174 1.60 TBA480Q 1.84

Terms of business: CWO. Postage and packing valves and semiconductors 50p per order. CRTs 51.50. Prices excluding VAT, add 15%. Telephone 01-677 2424/7 Price ruling at time of despatch. Telex 946708 Prices correct when going to p 'ass. In some cases prices of Mullard and USA valves will be higher than those advertised. E. & O.E. Account facilities available to approved companies with minimum order charge f10. Carriage and packing E1.'00 on credit orders. Open to callers Monday -Friday 9 a.m.-5 p.m. Over 10,000 types of valves, tubes and semiconductors in stock. Quotations for any types not listed. S.A.E. WW12 CIRCLE 64 FOR FURTHER DETAILS.

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 13

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by R.M. Adelson Music keys for the BBC microcomputer Two programs - one for playing music using the BBC computer sound generator - supplement this discussion of software for the economical polyphonic keyboard interface. Hardware was presented in the July issue.

As described in the July issue, the both the natural way to deal with (lines 1270 to 1320) that an inter- keyboard communicates with the interrupts and is efficient in mem- rupt has been received and ser- computer by sending an interrupt ory usage and speed. The default viced and that there is therefore through the handshake line CB, setting of HIMEM in MODE 7 is something new to display. Data on the user port. This initiates a 7C00 (hexadecimal). Line 440 read in from the keyboard is routine which reads the keyboard sets aside 256 bytes for the stored in eight bytes starting at in bit -mapped form into eight assembled code. The interrupt M% (line 450). These eight bytes memory locations, in accordance routine is in two sections, the first are initially set to zero by lines with the flow diagram given previ- (lines 520 to 750) being assem- 480 to 500. By referring all these ously. Details are given in List 1. bled at HIMEM, the second (lines variables to HIMEM, the assem- This is a keyboard -read utility 760 to 1060) at HIMEM+30. A bled code is easily relocated which can be used on its own to short initialising procedure which should, for example, the user check functioning of the keyboard configures the versatile interface wish to use a different MODE hardware, or as part of a more adaptor, v. i. a. , and tells the com- (illustrated in List 2). elaborate program (e.g. List 2) puter where to find the interrupt - I assume that the reader has designed to exploit the interface servicing routine is assembled at some familiarity with the BBC Ronald Adelson more fully. is with the HIMEM-I-70. The variable assembler and the IRQ vector Centre for Research into The main part of List 1 is writ- FLAG1 (line 470) is used as a system. The subroutine SETUP Applications of Computers to ten in assembly language which is message to the display routine (lines 1070 to 1210) which is Music, University of Lancaster. ELECTRONICS & WIRELESS WORLD DECEMBER 1984 17

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called at line 1250, sets the regis- 230 VDU19,2,8,0,O,O:VDU19, 1,0,0,0,0 ters of the 6522 v.i.a. (B) (which 240 DIMA%(11) is memory -mapped from FE60 to 250 FORIY.=0TO11:READAY.(IY.):NEXT 260 DATA&88,&22,&22,&88,&88,8,22,&22,&88,&88,&22, FE6F) as follows &88,&88,&6C30,8,6908,&6AFO,&6C50,&6C38,&6810,&6AFB, 8,6C58,&6C40,&6818,8,6C48,8,6C60 -data-direction register B 270 A=LN(1780):B=LN(2)/12 (FE62) all inputs 280 FORK%=0705 290 FORJX=0701 -auxiliary-control register 300 READ PAX% (FE6B) to give single -shot 310 FORI%=0703: FORPATX=0707 320 PAXX7PATX=A%(2*K%+J%):NEXT 1 interrupts from timer 330 I 1 X=4* I %+2*JY.+16*KY. -peripheral-control register 340 ?(TIBLEY.+IIX)=PAXXMOD2S6:?(TIBLEX+IIX+1) =PAXX DIV256 (FE6C) to give interrupts on 350 PAXX=PAXX+&38 positive -going edges of CB1 and 360 X=125000/(EXP(A+(KY.+6*JY.+12*IX-45)*B)) 370 IIX=INT(X+.5) set CB, high 380 TUBLEY.?(4*IY.+2*J%+16*KX)=I1Y.MOD16 -the interrupt -flag register 390 TUBLEX?(4*IX+2*JX+16*KX+1)=Il%DIV16:NEXT 400 ?(TIBLEY..+&60)=&10:?(TIBLEY.+&61)=&6D (FEED) cleared 410 FOR PATX=0T07:?(PATX+&6D10)=&B8:NEXT -interrupt-enable register 420 X=125000/(EXP(A+3*B)) (FE6E) has CB1 430 IIX=INT(X+.5) and timer 440 TUBLE7.7&60=I 1X80016: TUBLEX?&61=I1%DIV16 1 interrupts enabled. 445 REM Lines 450 to 1220 inclusive 446 REM are the corresponding lines of List 1 List 1. Basic with 1230 PX=DISPLAY This routine also stores the 1980 .CH1 LDA TUBLEX,X 1240 OPTIY. assembly -language program 1990 ORA M&CO location (HIMEM) of the user 1250 LDA 4$&15 2000 STA &FE4F for the BBC microcomputer 1260 LDX 117 interrupt service vector (IRQ2V) JSR SEND 1270 JSR &FFF4 2010 music keyboard interface TUBLEX+I,X in locations 206/7 (note that the 1280 DEX 2020 LDA 2030 STA &FE4F stores key information in 1290 JSR &FFF4 coding assumes that the low byte 2040 JSR SEND bit -mapped form in eight bytes 1300 DEX of HIMEM is 00). 1310 JSR &FFF4 2050 LDA *WO 2060 ORA VOL%. at HIMEM. On of 1320 LDA M3 receipt an interrupt 2070 STA &FE4F 1330 STA FLAG3 List 2. This program for the on 2080 JSR SEND request CB,, the code at 1340 LDA M&FF:STA &FE43 2090 .NECH DEC FLAG3 BBC microcomputer uses key HIMEM is entered (line 520). 1350 LDA MO 1360 STA COU 2100 RTS information from List 1 to play This stores the 6502 A, X and Y 2110 .FLASHA NOP:JMP FLASH 1370 INC FLAG1 2120 .SEND LDA MO the computer's internal sound registers on the stack and dis- 1380 .STI SEI 2130 STA &FE40 1390 LOX COU generator and display a map of rupts further interrupts on CB, 2140 LDY M&A 1.100 CPX *6 the keyboard status. 2150 .ROU DEY (lines 590 - 600). Timer 1 coun- 1410 BED LASTA 2160 BNE ROU

1420 LDA MY.+1 , X 2170 LDA *8 L- i S t 1 960 STA &206 1430 LDY MO 2180 STA &FE40 970 STA FLAG1 1440 .SHIFT ASL A 2190 RTS 430 MODE7 980 LDA M&50 1450 PHA:STY 8,70 2200 .FLASH LDA TIBLEY.,X 440 HIMEMa&7800 990 STA &FE6D 1460 BCC RST 2210 STA 8,71 450 MXaHIMEM+&913 1000 PLA 1470 JSR SET 2220 LDA TIBLEY.+1,X 460 SETUPaHIMEM+&70 1010 TAY 1480 JMP OVER 2230 STA 8,72 470 FLAGI=HIMEM+&6A:?FLAG1=1 1020 PLA 1490 .RST JSR RESET 2240 LDY *8 480 FOR I%=0 TO 4 STEP 4 1030 TAX 1500 .OVER PLA:LDY &70 2250 .COY DEY 490 M%!IX=0 1040 PLA 1510 INY:INY 2260 LDA N&F0 500 NEXT 1050 RTI 1520 CPV M&10 2270 AND (&71),V 510 FOR IX=0 TO 2 STEP 2 1060 1530 BED CLEI 2280 STA (&71),V 520 PXaHIMEM 1070 P% SETUP 1540 JMP SHIFT 2290 TYA 530 (OPT IX 1080 COPT I% 1550 .CLEI CLI 2300 BNE COY 540 PHA 1090 LDA MO 1560 LDA FLAG1 2310 LDX COU 550 TXA 1100 STA &FE62 1570 BEO DISPLAY 2320 RTS 560 PHA 1110 STA &FE6B 1580 INC COU 2330 .RESET TIA 570 TYA 1120 STA &206 1590 JMP STI 2340 ASLA:ASLA:ASLA:ASLA 580 PHA 1130 LDA M&FO 1600 .LASTA NOP:JMP LAST 2350 CLC 590 LDA *&10 1140 STA &FE6C 1610 .SET TXA 2360 ADC &70 600 STA &FE6E 1150 LDA M&7F 1620 ASLA: ASLA: ASLA: ASLA 2370 TAX 610 LDA *&20 1160 STA &FE6D 1630 CLC 2380 LDA TIBLEY.,X 620 STA &FE64 1170 LDA M&DO 1640 ADC &70 2390 STA &71 630 LDA N&4E 1180 STA &FE6E 1650 TAX 2400 LDA TIBLEX+1,X 640 STA &FE65 1190 LDA MHIMEM DIV256 1660 LDA FLAG3 2410 STA &72 650 LDA M&30 1200 STA &207 1670 BED FLASHA 2420 LDY *8 660 STA &206 1210 RTS 1680 JSR PLAY 2430 .COY1 DEY 670 LDA N&10 1220 I 1690 JMP FLASH 2440 LDA M&F 680 STA &FE6D 1230 NEXT I% 1700 .PLAY CMP *3 2450 ORA (&71),Y 690 PLA 1240 Q%=2 1710 BNE CH2 2460 STA (&71),Y 700 TAY 1250 CALL SETUP 1720 LDA TUBLE%,X 2470 TYA 710 PLA 1260 CLS: PRINT: PRINT: PRINT: PRINT 1730 ORA M&80 2480 BNE COVI 720 TAX 1270 REPEAT: UNTIL?FLAG1=0 1740 STA &FE4F 2490 LDX COU 730 PLA 1280 FOR I%=0 TO 7 1750 JSR SEND 2500 RTS 1290 PRINT"MX?IY.;" LDA M&FF 740 RTI 1760 LDA TUBLEY.+1 , X 2510 .LAST 750 1300 NEXT 1770 STA &FE4F 2520 CMP M%+7 760 PY.aHIMEM+&30 1310 ?FLAGI=I:PRINT 1780 JSR SEND 2530 BED FL 1320 GOTO1270 770 COPT IY. 1790 LDA M&90 2540 LDA M&88 780 PHA 1800 ORA VOL% 2550 JMP DOWN 790 TXA 1810 STA &FE4F 2560 .FL LDA FLAG3 BOO PHA 1920 JSR SEND 2570 BED FLA 810 TVA L_ i st 2 1830 JMP NECH 2580 LDX 4:8,60 820 PHA 1840 .CH2 CMP M2 2590 JSR PLAY 830 LDX *0 100 MODE7 1850 BNE CHI 2600 .FLA LDA 416.80 840 .AGAIN LDA &FE60 110 *FX9,10 1860 LDA TUBLEX,X 2610 .DOWN LDYM7 B50 STA MX,X 120 *FXIO,10 1870 ORA *&AO 2620 .ROUND STA &6D10,V 860 INX 130 INPUT"VOLUME 0-15 (ppp-ff)"VV. 1880 STA &FE4F 2630 DEY 870 LDA N&DO 140 IF(V%>150RV%<0)GOT0130 1890 JSR SEND 2640 BPL ROUND 880 STA &FE6C 150 MODES 1900 LDA TUBLEX+I,X 2650 CLI.RTS:I 890 LDA *WO 160 HIMEM=&5500 1910 STA &FE4F 2660 NEXTIY. 900 STA &FE6C 170 FLAG3=HIMEM+&6C 1920 JSR SEND 2670 CALL SETUP 910 CPX NB 180 VOLX=HIMEM+&69:COU=HIMEM+&68 1930 LDA M&B0 2680 REPEAT:UNTIL7FLAG1-0 920 BMI AGAIN 190 DISPLAY=HIMEM+&A0 1940 ORA VOL% 2690 IF7M%<>&FF PRINT"SYNC 930 LDA M&90 200 TIBLEX=HIMEM+&200: TUBLE%=HIMEM+&280 1950 STA &FE4F ERROR".END 940 STA &FE6E 210 7VOL%=IS-V% 1960 JSR SEND 2700 CALL DISPLAY 950 LDA *0 220 VDU23j8202{0(0)0( 1970 JMP NECH 2710 DOTO 2680

18 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

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ters are then loaded to give a spurious pick-up of electrical taken to bit zero of byte seven, so Circuit boards for this project will time-out after 20ms (lines 610 to noise. However, since sorting out playing top C should produce be available from Lancaster ITEC 640). These latter two actions some teething troubles with the for around £10. Please send an give a 20ms delay for residual prototype, synchronization prob- FF0000OFF s.a.e. to the ITEC at St Leonard's switch -bounce to die out and to lems have been rare. Some sug- House, St Leonardsgate, Lancaster, 1 allow for slight differences in the gestions for dealing Playing several notes at once Lancashire, LA1 NN with any that for further information. closing times of switches if more do arise are given later. should, of course, affect all the than one note is altered at a time. Assuming all is well at this relevant bits and thus will be ref- This amount of delay seems to be point, releasing the key should lected in the values of the bytes about right, but it is easily altered produce displayed. The system responds (up to about 65ms without any quickly despite the 20ms delay it significant change in the coding) FF000000FE is easy to obtain multiple readings by changing the bytes loaded at when playing chords unless one Pressing the lowest C# should lines 610 and 630, noting very carefully presses the notes that produce 4E20 is the equivalent of 20ms evenly. In practice this is not (decimal). FF0800000FE likely to be of consequence since The low byte of IRQ2V is such spurious responses can be rejected by software if altered to point to HIMEM+30 and so on. Notice that the lowest necessary. To terminate this program press (lines 650-660) and the CB, inter- six notes (C to F) are taken to bit ESCAPE. rupt flag cleared (lines 670-680) seven of bytes one to six respect- before the A, X and Y registers are ively, the next six notes (F# to B) List 1 is all that is necessary to restored from the stack and the are taken to bit six of these bytes, read data from the keyboard into return -from -interrupt is per- etc. This is to avoid a large num- the computer, which can then be formed. Thus interrupts are re - ber of p.c.b. wire crossings. Thus used as desired. As an illustra- enabled during the 20ms delay to byte one contains the bits for the tion, the program in List 2 uses allow the computer to go about its four F#s interleaved with those of the data to play the computer's housekeeping duties. the first four Cs, byte two con- three -channel sound generator. It When timer 1 times out, code tains the Gs interleaved with the also displays a representation of at HIMEM+30 is entered (line C#s, etc. Top C (the 49th note) is the keyboard on the screen. The 760). Again, the registers are saved, and port B of the v.i.a. is read and stored in the l.s.b. of M%. CB2 is then brought low (lines 870-880) and high again (lines 890-900) thus clocking IC,u Computers and Music at Lancaster in the interface. Lines 840 and 920 are looped eight times in all, The University's Music Depart- bytes minor and play the pair of notes say, the violin to have an accom- the being read into consec- ment is interested in all aspects of memory on the keyboard after which the paniment which is gradually utive locations by the computers as a musician's aid but offset X (lines 850-860). CB, computer displays its version. A speeded up as the pupil's profi- not so much with synthesizers. score of successes is kept. ciency increases. interrupts are enabled again Our main current interest is in the The 'rhythm box' allows (lines 930-940); IRQ2V is res- potential of the as a o Interval recognition plays and computer rhythm information to be accu- tored to its previous value (lines teaching aid for music theory and displays a random note from any- rately fed into the computer by 950-960); FLAG1 is reset to zero aural training, right through from where on the keyboard then tapping on the box with a pencil. as a signal to the display routine beginners to university/college selects and plays another random that the Its main purpose is to use the keyboard has been read level. The biggest problem until note from the same octave but again; the interrupt computer to give feedback on the flags are now has been the lack of a satis- doesn't display it. The pupil has to cleared and the interrupt routine recognize the interval and play type of rhythm exercises nor- factory means of student feed- mally terminated. The Basic display the second note. Again a score is carried out by hand clapp- back to the computer, the type- ing. It also has some interesting routine at lines 1270 to 1320 sim- writer keyboard being kept. unsuitable recreational (and perhaps compo- ply loops in line 1270 until for this, except at a rudimentary o Triad recognition plays a tonic sitional) possibilities. For exam- advised by FLAG 1 that its atten- level. tion is required. It then prints the triad in close position (any key, ple, a tune can be played into the We have now successfully root position or an inversion). computer through the keyboard values of the eight -bytes from designed two economical acces- M% in two The computer displays the key and its rhythm altered by tapping -digit (line 1240) hex- sories which go a long way toward name but not whether it is major out a new rhythm on the box. adecimal fields. solving the music -input problem or minor and the pupil has to play Our next hardware project is To test the interface, run this the four -octave music key- program - the correct chord on the key- to enhance the computer's sound and press the bottom board and a 'rhythm box'. Key- board. Both the computer's and capability. Direct musical input to note on the keyboard. This board software packages for the the pupil's versions are then dis- the computer from voice or musi- should cause the line BBC microcomputer currently played. cal instrument is also a possibil- under development include Further teaching software envi- ity. In the more distant future we FF 80 0 0 0 0 0 FE envisage small o Keyboard familiarity, in which saged includes recognition of cad- computers being used for music transcription, the computer displays a note on ences, musical dictation and to be displayed (bytes 0-7). Byte editing, printing, the stave and the pupil has to transposition. etc. The centre zero should always be FF as has expertise in music, comput- explained in the July issue. If the identify the note on the keyboard. We also have software for playing musical phrases into the ing, engineering and other disci- FF appears elsewhere (or not at plines and is well placed to make all) of o Major and minor thirds, in computer through the keyboard then the interface is out real contributions in this field. synchronization and the reasons which the computer plays a major and replaying them at different for this need to be explored. Cir- or minor third at random and dis- speeds. These phrases can be plays cuit IC,,, not resetting to zero on the lower note on the stave. stored on disc or tape which offers switch -on is a possibility, as is The pupil has to identify major or the possibility for pupils learning,

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 19

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representations of those keys that (TIBLE% and TUBLE%). The are pressed change colour if a former of these is concerned with Flush colour monitor is in use, or flash if the visual display, the latter with sound generator the monitor is monochrome. The bytes sent to the sound i.c. listing given is for a monochrome Although the BBC Basic SOUND Number of sound monitor. Note that lines 450 to instruction can be accessed from channels available 1220 have been omitted from the machine code through OSWORD, (Flag 3)=3 printed listing, as they are ident- I decided against this because the ical to the corresponding lines of program was required to work as List 1. fast as possible and tests with COU =O Code from lines 1230 to 2650 SOUND showed that the parame- is an assembly-language program ters recommended in the User which controls the visual and Guide for setting the pitches pro- Flog 1 =1 sound display described above. In duced sounds which were very effect it replaces the display rou- nearly half a semitone sharp. tine at the end of List 1. An earlier Since this program effectively Disable interrupts version of this, written in Basic, turns the computer into a micro - was much too slow at handling the synthesiser which users might display, taking about 1.25s to wish to play with other instru- Yes update it each time. No doubt it ments I felt it expedient to recal- could have been speeded up but culate the appropriate values to since about two orders of magni- get as close as possible to an tude would have been required it equal -tempered scale based on Examine next byte, was abandoned in favour of the the standard A of 440Hz (the first bit assembly version. sound system in the BBC micro- The first part of the program computer leaves much to be sets the flash rate to a more suit- desired both in terms of the noise able value than the default and it makes and the accuracy with asks for the volume level which it can be tuned, however required. Perhaps `ppp' is some- that is another story). thing of a misnomer since enter- To convert the program for use ing a value of zero would turn the with a colour monitor either Calculate entry sound generator right off produc- remove the first part of line 230, point in TUBLE % ing glorious silence. Mode five or change the number eight in this (four-colour) is used and HIMEM instruction in accordance with the set to allow 300 bytes for the table given on page 224 of the Yes assembler code, various flags User Guide. This instruction cur- etc. and two look -up tables Continued on Page 34

Yes

Send pitch and Send pitch and Send pitch and volume code to volume code to volume code to sound channel 3 sound channel 2 sound channel 1

Flag 3 = Flag 3-1

Calculate entry Calculate entry Send appropriate point in TIBLE point in TIBLE code to sound i c. as above

Send flash byte Send steady byte to 8 bytes to 8 bytes of screen memory of screen memory

Send steady bytes Send flash bytes to screen to screen Examine next bit

0

Enable interrupts

Enable interrupts Flow diagram of List 2 assembly code for handling display and sound (lines

COU = COU +1 1230-2650).

2i, ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com LIQUID CRYSTAL DISPLAY by T. Segaran. Multiplexing Liquid Crystal Displays A short description of the `black art' of driving 1.c.ds.

Although I.c.ds are finding their need a direct current to light damaged by prolonged direct vol- uses in various products, driving them. Multiplexing leds is there- tages and have slower response them seems to be a bit of a black fore a relatively simple matter - times than leds. Because of this, art. Many users tend to connect Fig. 1 shows a suitable arrange- the multiplexing scheme for the appropriate driver chips and ment. The segment lines (8) and 1.c.ds is rather more complex. the displays together, without the digit -enable lines define the When no multiplexing is needed fully appreciating the intricacies particular segments that need to (because few digits are being of multiplexing the driver. Below be lit up. As long as each digit is driven, say 4) the arrangement is presented an explanation of addressed about 50 times per shown in Fig. 2(a) is adopted. various levels of multiplexing. second, no flicker will be visible Each segment of each digit has a It is best to start by drawing an to the human eye. unique line running to it from the analogy with driving leds, which L.c.ds, however, can be driver. The backplanes of all the digits are commoned and are also connected to the driver. Hence, a Digit enable, connected to cathode four -digit display will have 32 segment connections and a com- Fig. 1. Use of d.c. enables simple method of multiplexing mon connection, which carries lads. square wave of equal mark: space ratio, as in Fig. 2(b). All seg- ments that need to be lit have a waveform which is 180 deg. out of n. phase with the common, as at (c), while those that do not have a waveform in phase with the com- mon. Figure 2(d) shows the resulting polarizing waveforms across the segments that are selected. The non -selected seg- ments have no net voltage across Orner them. Segment dota When two-way multiplexing is needed, the scheme in Fig. 3(a) is adopted. There is a connection from the driver to a pair of seg- ments and there are two back- plane connections to each digit. Com

Fig. 2. Without multiplexing, Vlcd 7 I 1.c.d. drive simply requires a (b) line for each segment and a frnme common lead, which carries a Vlcd ¡ IC) 1:1 square wave, as in (b). o u l Segment drives are either in Vlcd phase or antiphase with -- Idi common line waveform. o 3 lo) 5 8 -Vlcd --- Segment- no. Segment 9to16

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 21

www.americanradiohistory.com LIQUID CRYSTAL DISPLAY

Thus, for example, in an 8 digit Fig. 3. Two-way multiplexing display there would be 32 seg- requires two common lines. ment lines and 2 common lines. Com1 Notice that the common 2 wave- Corn 2 form shown at (b) lags behind the common 1 waveform by 90 degrees. When segment 'a' needs to be lit up and segment 'b' must be off, then the waveform shown e at (c), is impressed on the seg- ment 1 line. The first half of the waveform is 180 deg. out of phase with common one thus lighting up

segment 'a' and the latter half of 2 3 4 the waveform is in phase with loì 4' Segment no. Segment 5to8 common two, thus switching off segment 'b'. A similar waveform at (d) on segment 2 lights up seg- ment `e' and keeps segment 'd' switched off. Thus, although one reduces the number of lines by a factor of two, an additional com- lcd r Vlrd plexity of a special waveform with lcd - three voltage levels is needed, to J V 0(b) Jz - implement two-way multiplex- 1 frameframelcd 2 ing. fV 0 Three-way multiplexing is not

commonly used, but four-way 2 multiplexing can be discussed. In o - scheme, shown in Fig. 4(a) this Vlcd each segment line from the driver is connected to four segments in fc) each digit. There are four com- o to - mon connections (backplanes) each digit, each common line con- necting to two segments in each digit. Each waveform on the com- line. Note that this waveform is 'h' are off, then the waveform mon lines in (b) is 45 degrees out 180 degrees out of phase with shown in Fig. 4(d) is applied to of phase with the previous one. If each of the peaks in the common the segment 2 line, resulting in all four segments connected to waveforms, resulting in a large the appropriate polarizing vol- the segment 1 line (a, d, e and f) polarizing voltage across the four tage. Figure 4(f) shows the vol- need to be lit, then the waveform segments, as at (d). If segments tage across a non -selected seg- shown at (c), is output on that 'b' and 'c' must be lit, while 'g' and ment. Four-way multiplexing, although reducing the intercon- Group of 4-digit Lucid 1.c.ds nection between the driver and from EE Valve Company l.c.d. considerably, requires still more complex drive circuitry and four voltage levels. Another dis- advantage is that the difference in voltage applied to a selected seg- ment compared to that applied to a non -selected segment is less than in other cases. Table 1 sum- marizes the drive volts. Multiplex drive of alphanum- eric and graphics 1.c.ds follows the same principle used in driving

Table 1.

Static 2 -way 4 -way

Voltage levels 2 3 4 required 0, V,cd 0, V,cd/2 0, V;cd/3, 2V1cd/3, VCtl

Selected segment V,cd

Non -selected segment voltage (r.m.s.) 0 V,Cd/4 V,Cd/3

ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com LIQUID CRYSTAL DISPLAY

V<

2xV(cd -V( cc) Fig. 4. Four-way multiplexing, 3 needing four common lines. Vlcd V(cd - o

Vied 2xVlcd3 0 Vlcd3 V(cd3 o 0

-Vlcd - 3

numeric displays. The number of ence voltages for the steps can be VI d The threshold for an l.c.d. common lines used can get as defined. For example, when 16 segment must be between these high as 8, 16 or 32: the limiting common lines are used, the vol- two levels and the tolerance on factors are how closely the tage across a selected segment is the reference levels must be an thresholds on the displays can be 1/4 VI d and the voltage across a order of magnitude better than determind and how well the refer- non -selected segment is 11/80 those levels, i.e. about 0.1%. by Roy Hodges, MIEE SPEED OF LIGHT Light may, or may not travel at constant speed in vacuo, but it must do when it meets matter.

The human mind possesses a last thing I wanted was anyone to agation of radio waves, was a very strong urge to seek after the destroy this illusion - and in any electromagnetic one. It seemed truth; but is it perhaps a feeling of case, all the loose ends appeared so natural that the magnetic field pseudo -religious fervour which to be well taken care of by the Spe- created by the accelerating elec- allows us to accept theories and cial Theory of Relativity. I there- trons in an antenna, should com- phenomena which are not easily fore became very sceptical about bine with the electric field across comprehensible or are even par- articles I read which dared to sug- various parts of it to send forth an adoxical? One rather perplexing gest that some aspects of the the- electromagnetic wave. Despite concept falling within this cate- ory were perhaps a little suspect. these views, however, I was very gory is the constancy of the speed I voiced, rather than seriously uneasy about the classical con- of light notwithstanding any considered the point that if the cept of electromagnetic propaga- velocity the light source may have theory were not as stated there tion. It was not until I took cou- relative to that of the observer. appeared to be no other satisfac- rage and seriously questioned my When my own study of ele- tory explanation of the peculiar electromagnetic model that some mentary physics brought this way which light seemed to rationality dawned. seemingly illogical concept into behave. Certainly all experiments Although it is often convenient focus, I recall being rather more appeared to show that the speed to reason in terms of electromag- intrigued than bewildered. And of light is constant. And it also netic fields, the important part when this concept was linked to appeared logical that the speed of that matter plays in their propaga- relativistic notions and drama- light should be constant every- tion can easily be overlooked and tized by the story of a frail old man where in the universe. forgotten. This, of course, is not being greeted by his very young Although I accepted the use- the case when one considers the twin brother on his return from a fulness of considering the photon quantum model and that photons trip round Andromeda, I became in some circumstances, the actually emanate from within the fascinated by the possible credib- model I built up in my mind to vis- atomic structure as a whole. ility of such mystical ideas. The ualize and explain, say, the prop- Well, the stuff that light is made of ELECTRONICS & WIRELESS WORLD DECEMBER 1984 23

www.americanradiohistory.com SPEED OF LIGHT

either does emanate from within 1.2 times our accepted value nearest star, whose distance is an atom or it doesn't. If it doesn't (with respect to Earth) or at more conveniently measured in then the present most popular exactly our accepted value with light years, a mean free path of electromagnetic theory may suf- all the Lorentz modifications to 1010km is quite insignificant. This fice, though continue to be con- the source in order to balance the means that light would hardly fused by the existence of books. The latter value, of have left a star before its velocity photons. But if it does emanate course, lands us right in the mid- is changed to that prevailing for from within an atom, one must at dle of our present jungle of con- the interstellar gas. Moreover, it least try to satisfy the concept of troversy - espcially with respect means that the velocity of its duality by modelling the photon to the supposed time dilation. As emitted light may have changed on say a toroidal package of elec- there are many persuasive and thousands of times before it tric and magnetic fields in quadra- intelligent people of great experi- reaches Earth. Another interest- ture. If, however, this makes one ence who cannot digest this ing thought is that any two nervous, better forget duality and principle, is it not logical, despite photons leaving the souce at the concentrate only on photons. all the rhetoric against their argu- same time are each likely to Whatever forces exist within ments, to conceive that this same encounter their first interstellar an atom, there is one inviolate law principle is not proven beyond all atom in anything from a few which states that the initial veloc- shadow of doubt. If we can toler- minutes to a few days after depar- ity of photons propagated from an ate the suggestion that there is ture. For this reason there would atom is constant, i.e. our just a tiny shred of logic in this be no defined frontal system. It is accepted value of approximately view, let us ignore (for a few true that after several thousand 3X108 m/s. It is, of course, fairly minutes) the Lorentz complic- possible changes in velocity, well understood that atoms can ations and consider what happens nearby photons should keep absorb and generate radiation at if we assume that the light from roughly abreast; however, there very specific frequencies. And, our moving object commences its is bound to be some random due possibly to the various trans- travel towards Earth at 1.2 times grouping giving the effect of - ition times of photons within an our accepted value. well how does the nursery rhyme atom's sphere of influence, it is First choose to imagine that a go? twinkle, twinkle ? also a fact that the speed of light in perfect vacuum exists between Even if any of the famous air is markedly different from that the moving body and the outer experiments to determine the in, say, water. It is adequately reaches of the Earth's atmos- speed of light could have been demonstrated, therefore, that all phere. With no atomic encoun- carried out in deepest space, the photons are profoundly affected ters on their journey, the ejected results would have been just the by atoms irrespective of any sign- photons would be entering the same as they are on Earth. ature frequencies or densities, atmosphere at the same Photons may well arrive to within when, during their flight through enhanced speed. However, on one atomic diameter of the appar- the universe, they enter the space their very first encounter with an atus at a velocity substantially governed by these particles. atom of its gas, the velocity of a different to the speed of light on There may even be room for argu- photon entering the particle will Earth but the velocity would be ment that such photons leaving be immediately reduced to the immediately changed relative to an atom's influence are not the velocity of light with respect to that of the apparatus on encoun- same ones which entered it. that atom, i.e. our accepted tering the first material interface. Whether or not this is the case, value. To maintain the frequency Any satisfactory measure- photons which leave the field of an (increased in this case by what ment of the speed of light in a near atom, must surely be subject to might be confused with the Dop- vacuum, would, of course, be the same law which governs pler effect), this lower but normal rather difficult. One possible way photons actually generated by the velocity would produce light of a would be to pass the light emitted atoms. shorter wavelength and of from a star through a segmented If this postulate can be course, blue shift. This also glass disk rotating at high speed accepted - and it doesn't exactly implies that the light would be of and noting whether the light violate any existing laws, it greater energy to compensate for passing through the glass over- velocity of the takes or falls behind the light The author becomes quite evident that the the reduced After his college studies were inter- speed of light measured by a sta- photons. which travels directly. For accur- rupted in 1943 by wartime circum- tionary observer must always be But a perfect vacuum, of ate results, the disk would have to stances, Roy Hodges commenced a constant, because the relatively course, does not exist and matter be an inconvenient distance from career in Broadcasting Engineering the B.B.C. at their Brook - dense air through which the appears to be present in the order the measuring device - perhaps by joining man's Park transmitting station. Being photons have been travelling is of several atoms per cubic cen- on the next Moon visit we may only 15 years old at the time, he natu- also more or less stationary with timetre of interstellar space. If know. There would, however, be rally felt himself a little at the deep end; respect to the observer. In fact, one considers that only a single no way of actually measuring the however, he later transferred to the initial velocity of, say, light emit- television service and after 10 years every encounter between a atom exists per cubic centimetre, with the Corporation, he joined the photon and an atom, ensures the then to a first approximation, the ted from stars with a pronounced Ghana Broadcasting Service and maintenance of this constant mean free path of the gas would be red or blue shift due to the levell- spent 8 years as Engineer in Charge velocity. in the region of 1010km. There- ing out process mentioned above. of various departments. For the next 2 years he was a stu- I am not saying that Lorentz Consider now what happens to fore, a photon travelling through dent at the Brighton College of Tech- light emitted by a body moving space, would, on average, contractions and quirks of time nology studying electrical and elec- towards the Earth at say 0.2 of the encounter an atom approximately are just fantasy - interpretation tronic engineering and within the fol- mem- speed of light. Depending on every 101'km. Even by astronom- of some phenomena suggest they lowing year obtained Corporate real. However, do we bership of the IEE. Since then, he has one's 'faith' (and let's face it, most ical standards, this is a fair dis- are quite worked extensively in Africa and the students, if not mature people, tance - about the same as the really need them to explain away a Far East with various international which in the fields of broad- will believe what they are told if diameter of our solar system - universal constancy of light organisations but is eaten up in about nine hours may not exist. Could not the tail, casting, electronics, product the argument is made to look management and education. plausible enough), light will by the travelling photon. How- in fact, be wagging the dog? either leave the moving source at ever, if we then consider just the & WIRELESS WORLD DECEMBER 1984 24 ELECTRONICS

www.americanradiohistory.com COMMUNICATIONS COMMENTARY

engineers have reported sound might have been a 243 - projection unit, with built-in Optical power (Electronic Letters, September line system if the EMI team had v.c.r. and cable tv tuner, That strange genius Nikola 13, 1984) on optical link of 216 - not tried the effect of changing marketed in the USA at about Tesla used to believe that km with a total attenuation of one divide -by -three $3000. communication by radio waas 46.3dB at 1.55µm, using 107 multivibrator into a divide -by - Sony are also to provide a simple: the real problem was to splices. five (243X5/3=405). The giant mosaic -type display (160 transmit power. In practice it system which gave Britain a ft diagonal) for Expo 85 near was not until the 1960s that it significant lead in world Tokyo, visible at distances up to television will be remembered 1 km. This uses light sources was shown possible to keep a Interscan or model helicopter flying by with affection by all who were having fluorescent -type cells beaming up microwave power TRSB? not unduly worried by the often with three electron flood audible 10.125Hz from the ground. Even today it line -whistle. sources, one for each primary is doubtful whether any A distinctly aggrieved piece by In association with 4.5 in image colour, with a common cathode orthicon practical use is made of power Philip Watson in Electronics tube cameras it gave to provide a 40m wide by 25m transmission - though at Australia (July 1984) complains really excellent black -and -white high screen with a 400 by 378 IBC82 it was suggested that that the microwave instrument pictures - and even the visible array. DBS sound radio transmitters landing system generally line -structure could have been on 26 MHz could be so powered known as TRSB (time reference alleviated if the public had taken in what seemed largely an scanning beam), chosen in 1978 kindly to spot -wobble techniques. by the International Civil Amateur engineering pipe -dream. It was interesting to learn at Aviation Organization and now Now the idea has spread to IBC84 that there is a revival of in production, although of Radio optical fibres with their interest in the USA in CSIRO origin, is seldom extremely low potential synchronized spot -wobble as an credited to Australia. As the attenuation but with thin fibres aid to high -definition television Interscan system it was first limited in power -transmission a technique oyiginated by New IARU field tested at Melbourne. - capability. Japanese engineers Alan Blumlein but which Leslie According to Philip Watson, have reported (Electronic Jesty strove to introduce for so "locator" the system should rank as one Letters, September 27, 1984, many years. It was fitting that From January 1985, a new of Australia's most significant pp811-2) transmitting 39 watts he was in the audience at IARU locator system will come scientific achievements, over 420cm of 1000µm - IBC84, though describing into use with the UK and adopted as a world standard in diameter fibre and believe that himself as "an unemployed possibly throughout the preference to competing designs with this diameter fibre the limit engineer". world. It will enable v.h.f. and from the UK, continental would be about 80 watts. Using IBC84 provided further u.h.f. operators to pass, in a Europe and the USA. Yet, he a CO2 laser with a wavelength of evidence of the very impressive single six -character coded adds, "it is both surprising and about 5.3µm the transmissions results that are possible with the group, information on the disturbing to find that loss is about 0.3dB/m. 1125 -line (60 Hz) NHK and the location of their stations to Australia's role in this It is suggested that the ability proposed 1249 -line (80 Hz) within a couple of kilometres. It development has been to transmit 40 watts "enables BBC systems. The pictures on replaces a European -only completely ignored overseas." us to use this fibre for some Sony's excellent 6ft winde "squares" locator system and Interscan TRSB operates on 5 practical applications" but the projection system could not be was originally devised by John GHz with a range of about writers do not expand on these. faulted, though both standards Morris, G4ANB as the 37km and, among its advantages Meanwhile, the international require over 20 MHz of video "Maidenhead" system. over still -current v.h.f., ILS can rivalry to transmit high-speed bandwidth and may never be In the new system the world handle several aircraft at the data over long lengths of optical possible in Europe for is divided first into 324 "fields" same time. The system, as a fibre, using coherent systems, terrestrial or 12 GHz satellite each covering 20° of longitude world standard and including continues. At a recent Open broadcasting, although suitable and 10° of latitude. Each field is developmdents introduced in Day at British Telecom for electronic cinematography labelled by two letters between the USA, is not subject to basic Research, Martlesham, the and closed-circuit "A" first patent restrictions but the working. and "R", the letter claim was made that the Single -tube colour cameras indicating the longitude starting Aussies are clearly sore that its adoption of superheterodyne are still finding it difficult to from 180° West; the second, origins and the early work at principles for reception compete with three tubes. For latitude starting from 90° South. CSIRO are being overlooked combined with the ability to display, the principle of the Thus most of the UK west of obtain a narrow -band coherent single -gun beam -indexing tube the Greenwhich meridian is in output from semiconductor has been around for a very long the field "10", but the Channel lasers has enabled BT to Farewell 405 time. On several occasions it Isles, Isles of Scilly and Lizard establish a world record by has been hailed as the coming Point, Cornwall are in field transmitting a 140Mbit/s (the During the first week of thing in brighter colour "IN", most of the Shetlands in BT notes gave 140kbit/s but I January, 1985 405-11ne displays. One of the few such "IP", and those parts of am assured this was in error) television (System A) will finally tubes actually in production is a JOEngland east of Greenwich in along 200km of fibre without disappear into history - where 1 in tube made by Hitachi for intermediate regeneration. A for the vast majority of viewers camera viewfinders. Sony Each field is then divided into long external -cavity laser being it has been for the past decade. Corporation, however, has 100 "squares" arranged as a 10 studied at Martlesham has a Announced as a British recently announced a new by 10 grid, each covering 1° of linewidth of only 10kHz and television standard (competing beam -index projection tube with latitude and 2° of longitude, can be tuned over a 13,000 GHz with Baird's 240 -line sequential a 5.25 inch faceplate and each designated by a digit "0" range, so opening the way for system) during 1935, it has ethylene glycol -water cooling, to "9", the first indicating frequency multiplexing a series narrowly failed to make 50 claimed to have a peak longitude, starting from the of independent transmissions years. The long-lasting brightness of about 1600 west, and the second the over a single fibre. Blumlein waveform, with lumen, roughly seven times latitude starting from the south. However, on the "anything positive modulation (excellent more than with good shadow - Finally each square is divided you can do I can do better" apart from susceptibility to mask tubes. The tube is being into a 24 by 24 grid of sub - principle, I note that Japanese ignition interference) and a.m. put into a home video squares, each covering 5

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 25

www.americanradiohistory.com COMMUNICATIONS COMMENTARY

minutes of longitude and. 2.5 of almost a fortnight during The conventional lead -acid allocations. Channel 5A, minutes of latitude, labelled by which no spots were visible on battery still tends to survive adjacent to the 144 MHz band, two letters, each in the range A the face of the Sun. We now only a limited number of will disappear, along with to X starting from the face a period of two or three charge/discharge cycles without television usage of three Southwest corner. Thus the years of sunspot minimum, with the plates buckling, shedding channels in the v.h.f. boardcast location of Edinburgh Castle the consequent lowering of the active material (which can band (Band 2) which 20 years using the new system is maximum usable frequencies, short-circuit the cell) or ago was made available to 1085JW. There is however no difficulty of working across the suffering from sulphation. New Australian television but are truth in the rumour that anyone day/night barrier, and the Zealand amateurs, in particular, now required for the expansion working out their locator group virtual fade out of the 14 MHz seem prepared to tackle the of v.h.f./f.m. radio. But it may correctly at the first attempt will and higher bands at night. problem of regenerating cells by be years before these decisions be excused from taking the It will be interesting to see if such techniques as washing out can be implementated. Radio Amateur's Examination. the IARU Region 1 the shed material, or by using PAT HAWKER, G3VA recommendation of no s.s.b. on Glauber's salt solutions to 10.1 MHz remains counter sulphation, in a manner Costly h.f.? unchallenged for long, with originally described in 1912 and In brief numbers of amateurs in Region also in Wireless World in 1941! inflation The September "Commentary" Exchange rates and 3 (Asia, Oceania) already up the cost of noted the Government's continue to push operating phone in this narrow imported top -of -the -range proposed transfer of the 22 band. Currently in Europe, c.w. Here and there radio transceivers, high -power broadcast amateur activity on 10.1 MHz is at only leading to a revival of interest in By October the sequence of transmitters belonging to the a moderate level. "economy" designs and home G4Z Class A licences was Foreign & Commonwealth construction, though a flexible, almost exhausted and GO Office's Communications and full -specification design is not a Back to batteries callsigns may begin to be issued Broadcast Department to the matter to be tackled lightly, on late in 1984 or early 1985. BBC. Four months after this the kitchen table. It has long been a truism that The Channel 4 play "CQ" became known, no final As an example of rising for portable operation it is took pains to provide an decision has been made, with prices, one notes that the basic relatively simple to convert authentic portrayal of amateur various committees examining Yaesu FT -ONE h.f. transceiver electric power into r.f.: the radio operating. No so TV the proposals which are bitterly is currently being offered at difficult part is finding an Times which must have upset opposed by many of the about £ 1570 compared with economic source of the basic some amateurs by saying that engineering staff. Though KO £ 1450 in October 1983 and electric power. With most "peppered throughout the still seems to hope to push £ 1295 in October 1982. The modern amateur transceivers entertaining script is the freaky these changes through, they are absence of UK production or designed for operation from 12- language of Citizens' Band cagey about suggesting any assembly makes the imported 14 volts d.c. as mobile units, radio"! possible timetable. equipment very vulnerable to many amateurs are finding that Pierre Lorain, F2WL's New battery technology is changes in exchange rates. the home construction of definitive book on the weapons, claimed as a key factor in the Japanese domination of the reliable regulated mains power radios and techniques of SOE new Peugot Electric 205 car world market for such supply units, fully protected published in France in 1972 has with a claimed operating range equipment is challenged only by against delivering an over - been published in the USA and of between 100 and 140 miles at a few American firms with, for voltage output, and capable of UK in an English -text average speeds of 45 and example, the innovative Drake supplying peak outputs for adaptation by David Kahn as 27mph and to speed of 60mph. firm now increasingly s.s.b. operation of over 30A, is "Secret Warfare" (UK, Orbis The 12 nickel -iron 6 volt concentrating on "professional" by no means as simple as it Publishing Ltd., 185pp £7.00 batteries have cells not markets, and with some of the may appear at first sight. Low- hard covers). It includes clear completely separated, and each remaining American firms cost, series -pass transistors, drawings of about 15 different can be filled from a single relying on assembly in the Far such as the 2N3155, although suitcase and pocket transmitter- opening; they provide about East. nominally rated at 10A, often receivers used for clandestine twice the energy of standard Nevertheless, it still remains prove to have "worst case" communications, 1941-45. cells of similar size with 1500 possible for newcomers, who do ratings of around 5A, and their While the recent excellent recharge cycles possible. not aim too high initially, to failure, invariably a short- BBC documentary series on Battery recharging however assemble a complete h.f. circuit, can typically put a SOE included sequences with takes 10 hours and the cost of transmitting station for less damaging 18-20 volts into an John Brown, G3EUR showing the batteries is very high, than £100 by using secondhand expensive transceiver. the use of radio equipment, it reflecting the use of expensive equipment and aerial based on "Crowbar" protection can seemed odd that a later episode materials. wire suspended from trees or similarly present unanticipated gave the impression that Phone-in radio programmes houses rather than aluminium design problems, even though Captain Hudson, the first SOE can be dangerous work in the tubing arrays mounted on nominally fail-safe. man with the Yugoslav USA. Alan Berg, a controversial towers. There is thus a growing belief Resistance, sent out his own host on KOA Denver was shot At the other extreme one that the simplest, most reliable radio messages. In face he was dead last summer, after having notes aerial tuning units, for and usually most economical accompanied by H.W. King, been threatened several times which many of us still use just solution for base operation of who now lives near Oban, as -by no means the first an odd coil and capacitor, 12V transceivers is the use of a radio operator, burdened down American broadcaster to be priced at around £350! float -charged car battery. The by a heavy Mark 3 transmitter gunned down apparently by More use now appears to be introduction of fully -sealed supplied to SOE by Intelligence. angry listeners. made by both newcomers and "maintenance -free" lead-acid Australian amateurs will PAT HAWKER, G3VA long-established amateur h.f. batteries help to overcome the benefit - but possibly not for stations of the lower h.f. bands, former fear of causing many years - from the including 1.8, 3.5 and 7 MHz, domestic damage to carpets etc. decision of the Department of reflecting the recent rapid due to acid spillage. Standard Communication to phase out decline in sun -spot activity, car -battery chargers can be some of the anomalies in including a period in September used with 4A or 8A rating. Australian television frequency 1984 26 ELECTRONICS & WIRELESS WORLD DECEMBER

www.americanradiohistory.com STEEL DISHED TOROIDALS WASHER OUTER INSULATION The toroidal transformer is now accepted as the standard in industry, overtaking the obsolete laminated type. Industry has been quick to recognise the advantages toroidals offer in size, weight, lower radiated SECONDARY NEOPRENE field and, thanks to I.L.P PRICE. WINDING WASHERS Our large standard range is complemented by DESIGN our SPECIAL INSULATION section which can offer a prototype service within 14 DAYS together with a short lead time on quantity orders which can be programmed PRIMARY to your requirements with no price penalty. WINDING

15 VA 50 VA 120 VA 225 VA 500 VA 62 x 34mm 0.35K9 80 x 35mm 0.9Kg 90 x 40mm 1.2Kg 110 x 45mm 2.2Kg 140 x 60mm 4Kg Regulation 19% Regulation 13% Regulation 11% Regulation 7% Regulation 4% Why a Toroid? SERIES SECONDARY RUS 2,010 6+6 416 4x010 6+6 1000 6x012 12+12 9 38 84016 25+25 10 00 Smaller size & weight to meet No vota Current 2x011 9+9 277 4x011 9+9 8 66 6x013 15+15 7 50 8x017 30+30 8.33 modern 'sl iml ine' requirements. 2x012 12+12 208 4x012 12+12 5 00 6x014 18+18 6 25 8x018 35+35 714 04010 6+6 1.25 Low 2403 15,15 1 66 4x013 15+15 4 00 6x015 22+22 511 8x026 electrically induced 0x011 9+9 0 83 40+40 625 2x014 18+18 1 38 4x044 18+18 3 6x016 25+25 450 noise demanded 04012 12+12 063 33 8x025 45+45 5 55 by compact 2x015 22+22 1 13 4x015 22+22 2 72 6x017 30+30 3 75 0,013 15+15 0.50 8x033 50+50 5 00 equipment. 2,016 25+25 160 44016 25+25 2 40 64018 35+35 3 21 0x014 18+18 0.42 8x042 55+55 4 54 High 2x017 30+30 0 83 4x017 30+30 2.00 6x026 40+40 2 81 8x028 110 4 54 efficiency enabling 04015 22+22 0.34 110 2x028 045 4x018 35+35 1 71 6x025 45+45 250 8x029 220 0x016 25+25 0 30 227 conservative rating whilst main- 2x029 220 0 22 4x028 110 1 09 6x033 50+50 2.25 0,017 30+30 0.25 8x030 240 2 08 2x030 240 020 4x029 220 0 54 6x028 110 2 04 taining size advantages. VA (encased in ABS plastic) 4x030 240 0 50 6x029 220 1 02 625 Lower operating temperature. 80 VA 140 x 75mm 5Kg 160 VA 64030 240 0.93 30 VA 90 x 30mm 1 Kg VA Regulation 4% 70 x 30mm 0.45Kg Regulation 12% 110 x 40mm 1.8Kg 300 Why ILP? Regulation 18% Regulation 8% 110 x 50mm 2.6Kg 94017 30+30 1041 94018 35+35 892 Ex -stock delivery for small 3x010 6+6 6 64 5x011 9+9 889 Regulation 6% 3x011 9+9 444 9x026 40+40 781 quantities. 1x010 6+6 2.50 5x012 12+12 6.66 7x013 15+15 34012 12+12 1000 9x025 45+45 6 94 1x011 9+9 166 333 5x013 15+15 5.33 Gold service available. 21 days 3x013 7x014 18+18 8 33 6 25 14012 1 15+15 266 9x033 50+50 12+12 25 5x014 18+18 4 44 7x015 3x014 18+18 22+22 682 9x042 55+55 5 68 14013 15+15 1 00 222 manufacture for urgent deliveries. 5x015 22+22 3.63 7x016 25+25 6 00 14014 18+18 0.83 3x015 22+22 181 94028 110 5 68 5x016 25+25 3.20 7x017 30+30 5 00 2 year no quibble guarantee. 34016 1 9x029 220 84 1x015 22+22 068 25+25 60 5x017 30+30 2.66 J 34017 7x018 35+35 428 9x030 240 14016 25+25 0 60 30+30 133 5x018 35+35 2.28 260 Realistic delivery for vol time 3x028 110 7x026 40+40 375 1,017 30+30 0 50 072 5x026 40+40 200 7x025 orders. 3x029 220 036 45+45 3 33 5x028 110 1 45 3x030 240 033 7x033 50+50 3 00 No price penalty for call off 5x029 220 0.72 74028 110 2 72 5x030 240 0 66 orders. 7x029 220 1 36

7x030 240 1 25

Prices including P & P and VAT Mail Order - Please make your crossed cheques or postal orders payable to I LP Post to: ILP Electronics Ltd., Dept. 3 VA Size VA Size Electronics Ltd. 15 0 7.06 160 5 12.17 Graham Bell House, Roper Close, 30 1 7.67 225 6 13.75 Trade - We will open your credit account Canterbury, Kent. CT2 7EP 50 2 8.90 300 7 14.97 immediately upon receipt of your first 80 3 10.06 500 8 19.60 order, Tel: (0227) 54778 Telex: 965780 120 4 10.65 625 9 22.30

For 110V primary insert "0" in place of "X" in type number. For 220V primary (Europe) insert "1" In place of "X' in type number. For 240V primary (UK) insert "2" in place of "X" in type number. IMPORTANT: Regulation - All voltages quoted am FULL LOAD. Please add regulation figure to secondary voltage to Obtain off load voltage. IL IF' ELECTRONICS LTD.. CIRCLE 27 FOR FUR'T'HER DE'T'AILS.

Affordable Accuracy - Low Cost Multimeters from Armon

SPECIFICATION SPECIFICATION HC 6010 DIGITAL HC1015 ANALOGUE * 10 Amp AC/DC * DC Voltage: 0.25, 2.5, 25, 250, * Battery: Single 9V PP3. Life: 1,000 Volts, 10,000 Ohms/Volt 200 hrs. * AC Voltage: 10, 50, 250, 1,000 * Dimensions: 170 x 89 x 38mm Volts, 4,000 Ohms/Volt * Weight: 400g inc. battery * DC Current: 1, 10, 500mA * Mode Select: Push Button * Resistance: 0 to 1 MegOhm in 3 * AC DC Current: 200NA to 10A ranges * AC Voltage: 200mV to 750V * Decibels: -20dB to +62dB * DC Voltage: 200mV to 1000V * Battery: One 1.5V size AA (incl) * Resistance: 20011 to 20M11 ARMON ELECTRONICS LTD. * Size & Weight: 105 x 63 x * Input Impedance: 10M11 32mm; 130gr * Display: 31/2 Digit 13mm LCD Heron House, 109 Wembley Hill Road, O/load Protection: All ranges Wembley, Middlesex 8AG 19 RANGES,COMPLETE WITH * HA9 BATTERY AND TEST LEADS * Accuracy: 0.5% DC Volts Telephone: 01-902 4321(3 lines). TELEX No. 923985 28 RANGES, EACH WITH FULL Please add 15% to your order for VAT. P&P free of charge. Payment by cheque OVERLOAD PROTECTION. BATTERY with order. Offer applicable to mainland UK only. & TEST LEADS INCLUDED TRADE ENQUIRIES INVITED. FULL RANGE OF METERS ON APPLICATION Please allow 15 days for delivery. CIRCLE 36 FOR FURTHER DETAILS.

PRINTED CIRCUIT BOARDS FOR IN VIEW OF THE EXTREMELY RAPID CHANGE TAKING ELECTRONIC & WIRELESS WORLD PROJECTS PLACE IN THE ELECTRONICS INDUSTRY, LARGE QUANTI- PROJECT DATE No. of BOARDS PRICE NIcD FAST CHARGER (NOV 83 ISSUE) 1 £7.00 TIES OF COMPONENTS BECOME REDUNDANT. WE ARE R.F GENERATOR (JAN 84 ISSUE) 20 £6.00 SC84 COMPUTER (MAY 84 ISSUE) 3*** £39.00 CASH PURCHASERS OF SUCH MATERIALS AND WOULD MODEM (JUN 84 ISSUE) 1* £16.00 SC84 POWER SUPPLY (SEP 84 ISSUE) 1 £5.00 APPRECIATE A TELEPHONE CALL OR A LIST IF AVAILABLE. EPROM PROGRAMMER (OCT 84 ISSUE) 2* £17.00 WE PAY TOP PRICES AND COLLECT. BOARD CODE:- * PLATED THROUGH HOLE SINGLE SIDED All P.C.B.'s are supplied with component insertion diagrams. Prices are inclusive of Inland and Overseas Postage, Packing and V.A.T. R. Henson Ltd. cW°.TD- Combe Martin 21 Lodge Lane, N. Finchley, London, N.12.5 mins. from Tally Ho corner ELECTRONICS Telephone 01 445 2713/0749 KING STREET, COMBE MARTIN, NORTH DEVON EX34 OAD TEL:- 0271 88 2346 CIRCLE 42 FOR FURTHER DETAILS. CIRCLE 37 FOR FUR'T'HER DETAILS. ELECTRONICS & WIRELESS WORLD DECEMBER 1984 97

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UK'S NO. 1 FOR TEST EQUIPMENT ACCESSORIES AND OEM STOCKS ELECTRONIC EQUIPMENT ACCESSORIES SOFTWARE PERIPHERALS MULTI -BOARDS

DIGITAL MULTIMETERS TV TEST EQUIPMENT PICK A CARD SOFTWARE Hand Held Models MDIS IC) INTELLIGENT IUK C/P 65p) - ANY CARD OISASSEMBLER ;l BUILD A CUSTOM SYSTEM HAND HELD MODELS FROM SCRATCH or expand For all CP/M based machines Controls S=Slide R=Rotary your GALAXY or NASCOM £50.00 PB=Push button Demonstrations for callers IVC HI-RES ICI For Gemini and others (please All leature AC/DC volts. enquire). Provide Pseudo high resolution MC32 Series TV colour Pattern Gen. GM811 CPU £125.00 DC amps Imany with AC graphics. £15.00 8 colours Video comp 0/P C/P £1.001 GM832 SVC £195.00 amps) ohms etc. UK C/P 65p1 *WITH CARRY CASE IUK GM829 FOC/SASI £ 145.00 DISKPEN ICO Version 3. Low cost word processor Meg ohmlSl MC32I PAL IUK) £229.00 *K025C 12 range 0.2A DC 2 £24.30 for Gemini and others (please enquire' £50.00 MC32B PAL B £229.00 GM813 CPU/ 64K RAM £225.00 *K D305 14 range IDA DC2 Meg ohmlSl £25.91 SECAM VERSIONS AVAILABLE EV814 IEEE 488 CONTROLLER £140.00 .rKD30C 26 range IA AC/DC 20 Meg ohmIR) MAXiFILE OVERLAY £20.00 £31.13 TC40 Portable FM & VHF/ UHF TV Find strength GM802 5411 DYNAMIC RAM £ 125.00 3500 30 range 10A AC/DC 20 Meg *METEX GM82787 KEY KEYBOARD £85.00 SPooLER OVERLAY £15.00 £36.75 meter BI to BIV with carry case. 45-882 MHZ ohm (RI STATIC RAM HENRY'S CP/M UTILITIES DISK ICI IUK C/P £1.001 £189.00 MP826 £185.00 * METEX 3510. 30 range 10A AC/DC. 20 meg ohm 41 Programs for the CP/M Systems programmer LHC 909 Serles Video head checkers GM816 MULTI I /0 £125.00 plus Hie tester plus cont. tester (R) £40.45 51/4 format £15.00 LHC 9098 Beta. l 10 828A SUPER PLUTO COLOUR GRAPHICS 601028 range IDA AC/DC 20 Meg ohmlPBl 8" format £17.35 £37.83 LHC 909V VHS IUK C/P 859) !£45.00 each PROCESSOR 192K RAM £499.00 range IDA AC/DC 20 Meg ALLDISC *KD55C 28 ohm'RI£38.70 LCT 91 OA CRT tester/rejuvenator. GM833 RAM-OISK 512K £450.110 Variable disc format utility for Gemini and Nascom * KD615 18 range IDA DC 2 Meg ohm plus Hle tester IUK C/P £I.50) £175.00 GM888 CPU/INTEK 8088 P0A CP/M's (RI £34.74 GM862 256K RAM £325.00 £150.00 7030 As 6010 but basic 'PH £46.91 GM837 COLOUR GRAPHICS DISPLAY £165.00 ALSO DIGITAL THERMOMETERS BDOSZ AND CCPZ 'each NC 5010 31 range 10A AC/OC Cont. buzzer 20M IUK C/P & export extra al cost) £10.00 Pocket size LCD thermometers complete All above - Please state format required. ohm IRI £43.43 FULL LEAFLETS/ DETAILS OF SUITABLE with battery. Accept any type K probe * DM3350 Autorange plus) cant lester 18 range PERMUTATIONS AND PRICE LISTS - SEND LARGE IUK C/P 6501 10A AC/DC 2 Meg ohm IRI £43.44 SAE TH301 LC050"C to 750 C. I C resolution COMPUTER POWER *DM2350 Mini aulorange plus cont. tester 19 range with thermocouple. £59.50 We can advise also with terminals and complete 10A AC/DC [20A Max12 Meg ohm 'POI £60.83 Galaxy computers with monitors and Disks ready louse SUPPLY TH302 LC0-00 C to 1100-C Cent/Fahrenheit 0.1 *3100 Pen type auto ranging AC/DC V 20 Meg Switched mode. Stabilised. Sell protecting S/C and I resolution with thermocouple. E79.50 ohm - buzzer £41.54 protected. etc. 220/240V AC 5V 3.3A 1211 2.4A Range of various probes in stock. £175010E25.00 SOAR ME540 Manual/Autoranging plus cont buzzer. NASCOM-2 40°mcycle -5V 0.5A -12V 0.5A. Suitable Apple Available in both kit and built form. Featuring replacement 19 range 100 AC/DC 20 Meg ohm (R) £41.54 (UK C/P £1.501 £50.00 VARIABLE Micros0lt Basic. NAS-SYS monitor. lull QWERTY METRIX HAND/BENCH PORTABLES (ITT) keyboard of the highest quality. 4MHz ZBOA POWER One 01 'Size 188 x 86 e 50mm Rotary canlrolsl processor. full RS232 I/0 and parallel 1/0 most Ilexible computer cards around. expansion MX5223'., digit LED 21 ranges 10A AC/DC SUPPLIES the COMPUTER FANS ^Aa. the NASBUS and UK C/P 509 each 85p pair 2 Meg ohm Basic 0.50..°'Rl £67.00 220/2400 AC input IUK C/P £IÁ01 capabilities are impressive using MX digit LED 29 ranges 10A AC/DC 20 compatible 80 -BUS expansion cards. Expansion 562 3'; PP241 single meter. A/V switch. 0/3011 QUANTITY DISCOUNTS includes hires colour graphics lull CP/M disk Meg ohm Basic 0.2°° Plus continuity tester IRI £95.00 lamp £33.00 AVAILABLE MX563 True RMS 3'.. digit 30 ranges 10A AC/DC system and much more. Send SAE for lull leaflets. PP243 3 amp version £52.13 4., 220/2300 AC Brand new £6.52 each 20 Meg ohm. 20HZ to 30KH2 0.1 °° buiclRl£155.00 NASCOM 2 kit £225.00 230N Twin meter 0/30V l A £97.00 33/,.. 113/, /I I5V AC Brand new £7.61 each digit True RMSm 21 ranges I OA AC/DC. NASCOM ?built £265.87 MX5754', 330N 3 amp version £175.00 43/, 220/240V AC Ex -units £4.78 each up lo 50KHZ D.05°, basic IRI £175.00 2302 Dual 0/30V 0/2A twin meter plus fixed 5V 1A 43/," 110/115V AC Ex -units £4.35 each EDUCATIONAL; also pulse generator. £230.00 ITT 2020 CABINET MIXED QUANTITY ANALOGUE Professional computer case with keyboard cutout. 18 x THERMAL & EXPORT DISCOUNTS MULTIMETERS 15 V . 4.5 'front slopes). PRINTER We would be pleased to quote. Contact sales office at General range )'mirror scalellUK C/P 65p) Ideal for single board ices 406. oll HC1015 15 range pocket 10K/Volt computers like the Nascom or Gemini Multiboard 13

I meg ohm £7.78 cards, etc). Very heavy gauge 1.25 I plastic with AUDIO AND RF HM 102BZ' 22 range 20K/Volt IDA metal base. Attractive silver grey finish. OC plus cont. Buzzer 10 Meg ohm IUK C/P £1.781 £19.95 GENERATORS h' 5 £12.61 (UK C/P C1.001 ETU3000 20 range 30K/V AUDIO 12A DC 12 meg ohm £18.26 TOROIDAL LEADER LAG27 5band sine/square 0/P 0/5V NH56R' 22 range 10K/Volt 6 Meg ohm £11.26 TRANSFORMERS e .tlliull handbook 26 range 30K/Volt I OAC/DC 10 Mega) RMS Dist 0.05°.0 20HZ to (MHZ £93.00 IUK C/P £1.001 ohm 100 watt isolations 230/240v £43.43 LEADER LAG 1204 5 band H INZ to I MHZ to 0.3V £21.7070 AC plus 8-0-8V 4A 15-0150 SUITABLE FOR: TANDY BBC DRIC NASCOM RMS into 600 ohm 005°°distsine/square £155.00 360TR" 23 range bench 100K/Volt. large scale 0.645A 309 0 154 size GEMINI ACORN DRAGON etc. LEADER LA61255 band 10HZtoIMHZto0.3V 10A AV/DC plus Hie lester. l0 Meg ohm £39.13 approx. 4' dia e 1), ¡Interlace units with leads £13.00 - state model) RMS into 600 ohm sine/square/burst signals 0.03°.° ÁT2100' 31 range de luxe 10OK/Voll 10A AC/DC. C/P 75p) (Your enquiries invited). dist °130.00 I00 Meg ohm £30.39 IUK £6.91 TRIO AG202A 4 band 20HZ to 200KHZ 10V RMS AT1020' 18 range de luxe 20K/Volt plus life 0/P 0.5°'°dist CR OSC 0/IOV pp 0/P £89.00 tester.5 Meg ohm £19.57 STC NOVATEL CHERRY KEY PADS band MHZ to I MHZ 0.1'° diet 0/7V YN360TR' 19 range 20K/Volt plus Ate tester TRIO AG2035 IUK C/P 40p either model) RMS £139.00 I Meg ohm £13.87 0/P PRESTEL 16 button key pads non- KRT5001' Range doubler 35 range total 10K/Volt RF encoded £5.17 Meg ohm TERMINAL TRIO S6402 6 range 100KHZ to 30MHZ AF 0.1 V 10A OC 20 £19.09 HEXADECIMAL15 ST303TR' 22 range 20K/Volt plus Hle tester I2A FEATURES RMS Int/ext mod £72.00 keypad (requires IC's) £6.52 LEADER LSG176 band 100KHZ to 150MHZ 196 to DC I Meg ohm £18.26 7 drag .green screen Metric Professional series in stock. ask for leaflet. AC mains 450MHZ to Harmonics' RF 0.1 1.) RMS Int/ext Mod AF [ITT) 2400 operated MODEM CARDS 1KHZ I volt 11MHZ X tal optional£3.001 £115.00 detachable key pad. robust COMPONENTS - case 14 x 12" x 7' cassette COUPLER PROBE KITS ACCESSORIES' TOOLS recorder data stored facility. Brand new. tested. answer and originate 300 BAUD video output for other uncased acoustic modern card by famous In wallets with adaptors. etc. BNC liftings for Large range in stock semiconductors. relays. tools. monitors. security lock. etc manufacturer. RS232 input/output. Power supply scopes/counters/generators. etc. Plus millions of capacitors. resistors. presets, controls. /-12V at 180mA. Requires 2 magnetic earpieces.2 XI £8.90 010 £8.26 0100 £16.00 plugs/sockets. etc. etc. For bulk export users. (UK C/P £3.00) lmPec £113.00 switches. 2 LEDs and connectors to complete. X1/010 Switchahle £10.00 Demodulator £16.00 Tel: 01-723 1008 with enquiries. Circuits and connection data supplied. (UK C/P tree with other Items 65p per Ito 3 kits) ASCII TRANSISTOR Card only. £26.04 KEYBOARD Card and remainder of small components £29.09 Compact. 64 key AC CLAMPMETER TESTER gI 69505 Telephone Direct Line coupler type LTU II MKI I. 0/300A. 0/600V AC 0/1 ohm. Total Direct reading PNP/NPN and diodes. sha" 5lunction keys. Hall Suitable for direct coupling PRESTEL adaptors and 9 ranges with carry case and leads Hfe. leakage. etc. General purpose TCI effect keyboard with the above acoustic modems. Integral Line select and ST300.10K C/P 65p1 £30.87 (UK C/P 65p1 £24.30 Lót reprogrammable 12716) ASCII output decoder autodial relays requiring TTL inputs. Circuits and EPROM. Steel key frame tor good rigidity. Negative connection data supplied. LTU 11 Coupler £13.00 going strobe. Requires -5 volt 12 volt supplies. 1200 BAUD receive 75 BAUD send direct coupled HIGH VOLTAGE METER ELECTRONIC IUK C/P £1 00) £21.70 modem for PRESTEL. Requires 59 supply with TTL Direct meter reading INSULATION TESTER 58 KEY ASCII inputs for data. line select and autodial. LTU 11 Is COMPACT direct coupler required. See above. Connection data LHM80A 0/40K V. 100 Meg with carry case. supplied. PRESTEL modem card. £13.00 IUK C/P £1001 £28.00 "11110 500Ví0 ohm KEYBOARD leads etc Contaclless capacitive high reliability keys. Full 128 Paper, YF501 (UK C/P 65p1 £71.74 ASCII codea.Steel key frame for positive rigidity. STOCKISTS FOR Printers. Thermal. Daley DIGITAL Wheel:. Dlek Drives Boxed. Ghouls also Winchester. I mS strobe. single 5 volt supply. Repeat key. control Monitors. Micros. BBC. Electron. Nascom, also Cables. CAPACITANCE end caps. lock. £28.26 IUK C/P £1.001 METER LOGIC PROBES plugs blank discs & tapes so ware, books. etc. TTL OTL etc -2iÌ DM6013 Direct read LCD 8 range Dip' LP2145 MHZ £21.OÚ ALWAYS KEYBOARD ta 200mld. 3!- digit 0.5°/° basic DP7030MHZ £25.00. DP71 50MHZ £52.01! rtv AND POWER SUPPLY IUK C/P 65p) £60.43 IUK Poet. etc. 6591 BARGAINS FOR CALLERS

Prices exclude VAT (15%11K orders only) Export please allow adequate CIF Let us quote for your requirements

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98 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

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OPEN 6 DAYS 4 nR," A WEEK - ALL STOCKS RYS ON DISPLAY AUDIO ELECTROf1IC5 r: .e EQUIPMENT COMMUNICATIONS COMPUTERStea. COMPONENTS oji LCD COUNTERS (UK C/P & INS 65pl Ex SCOPESAA models on display for callers, THANDAR battery portable 8 digit LCD counters. Size 255 a -` (UK C/P £5.00. VAT or Securicor £15.00 VAT) 150 x 50mm, Complete with batteries. ' - Optional: Carry cue £5.95 AC adaptor £8.95 TF040IOHZte40MHZ.IHZRes. f -81j HITACHI 49mV sensitivity. £ 1 20.00 A 2year warranty ALL MODELS 5m0IImV using x 5 TF2 to HZ. /lU, sensitivity. manHZ y features. magnifier I Supplied complete with 2 probes. A&B inputs. tc. £165.00 ( Not V212) TP600 600MHZ premier (Powered by computerl £45.00 V2I2 Dual 20MHZ. 6" tube. CHI 0/P. TV SYNCH I KHI TP 10001000MHZ IIGHZ) Prescater calibrator. Slim style. Size 310w x 130h x 370d. mm with power supply £67G5 .00 Probes -See lacing page £299.00 PFM 200 A Pocket 20HZ to 200MHZ LED counter 0.I HZ res I OmV. sensitivity £69.50 NEW TF600 LED 600 MHZ counter. P.U.A. V222 As 0212 Plus DC offset and alt. magnify functions. Also ext volts measurement fusing DVm) £395.00 GENERATORS Function and Pulse [UK C/P 65p1 %% ke THANDAR bench mains portable. Size 255 x 150 x 50mm Dual 0 MHZ h delay line and Options: Carry case £5.95 101/102/105 facilitiesV422 of 4V222 plusdmany other features. £ 610.00 T61010.02HZ to 200KHZ function. sine, square, triangle. Variable DC t. TTL 0/P Ext. sweep mode. Variable 600 V203F Dual 20MHZ. 5'/7" tube. CHI 0/P TV SYNCH. Delay hm 0/P ois £1 05.00 x T0102 0.2HZ to 2MHZ function. Sine, square. triangle. sweep. DVm 0/P volts 1KHZ calibrator. Size 275w 1 90h x Variable DC offset £155.00 400d mm TTL 0/P. Ext. sweep mode variable 6110 ohm 0/P. 10V PP £395.00 T6105 5HZ 10 5MHZ pulse. TTL and Sync 0/P. Variable 50 ohm 0/P. Free run. gated or trig. modes. £1f05.00 V353F Dual 35MHZ version of I/203F with delay line TG501 0 005H to 5MHZ function. ä £295.00 eruw»ii na £610.00 TG502 Sweep/function versionof above £495.00 _okNadbaw »10 ma. V650F Dual 60MHZ with delay line £850.00 TG503 AS T0501 plus pulse generator V1 O5OF Quad 100MHZ - loads of features £1095.00 £495.00 V209 Dual 20MHZ battery/mains £630.00 V509 Dual 50MHZ battery/mains, delay. etc. £1250.00 [UK C/P 8,50 VI34 Storage scope dual 10MHZ £950.00 LCD & LED MULTIMETERS V6015 Digital storage 2ch 1000 words/CH £ 1295.00 THANDAR BENCH PORTABLES Size 255 x V098 PAL TV Waveform monitor £ 940.00 150 x 50mm Option: Carry case £5.95 V088 PAL TV Vec for scope TM355 3'/z digit LED. 29 ranges. 0.25° ° basic. £1300.00 , 100mV res. 10A AC/DC. 20M ohm £85.00 I Optional: AC adaptor £6.951 digit LCD 29 ae TM355. CROTECH r3óóhour battery life (suppl1/2 gied)es £95.00 TM351 3'/z digit LCO. 29 ranges. 0.1% basic 303015MHZ portable 5mV/div 95mm display. Built in Ranges as above. 2000 hour battery life. £115.00 component tester. Trig to 20MHZ £179.00 3035 15MHZ 5mV/div 130mm 151 display. Built in LED COUNTERS IUK C/P 85p1 . component tester. Trig to 20MHZ METEOR mains or battery portable 8 digit LEO counters. Size £198.00 219 x 240 x 98mm. 5mV sensitivity 0.1 HZ resolution 3132 Dual 20MHZ. trig to 40MHZ. 2mV/div 130mm 151 100 5HZ to 100MHZ £95.00' display. algebraical add/sub.Reg DC 0/P's 5V and m 12V. Built- ' in component comparator 5HZ £121.00 £297.00 600 to 600MHZ A&B inputs 1000 5HZ to 1000MHZ I I GHZI A&B Inputs £165.00 Options: 6 NICHOS £10.60 RF pickup Aerial £7.75 (AC adaptor included)

HA MEG 2 year warranty FUNCTION GENERATOR NM 103 10MHZ 2mB portable. Trig to 30MHZ 60 x 70mm - i (UK C/P 65p) display. 1 KHZ calibrator. Built in component teeter. Size 212w JUPITER 500 Function generator 0.1 HZ to 500KHZ or better. x 114h x 280d mm . Sine. square. triangle 0/P to 7 30 volts. TTL 0/P. DC offset ö00 00 o - £167.00 15V variable. Ext AM sweep facilities 220/240V AC operated.d HM 203/5 Dual 20MHZ.2mV trig to40MHZ.IKHZ ca. 80a £110.00 t. 100mm display. Built in component tester. Slim design 285w x I 45h a 380d mm £264.00 THURLBY EQUIPMENT

x HM204-2 Dual 20MHZ 1 mV. Trig to 50MHZ sweep delay. 80 3017 (1 2036 100mm display. Z mod input. Size 250w x I 45h x , LABORATORY 380d mm £365.00 1+¡ POWER

HM605 Dual 60MHZ. 1 mV. Sweep delay. Z mod. 1 KHZ cal.. etc.. SUPPLIES â etc. Built in component tester. Size as HM204 80 x 100mm 434 DIGIT LCD WK C/P £2.501 display £515.00 MULTIMETERS Twin LEOread out 28 range 10mV Res. 10A AC/DC 32 Meg ohm Freq. (Volts/amps) 0.1°n accuracy. measurement function. (UK C/P £1.001 PL310 0/30V. 0/IA £118.00 1503 0.1% basic £159.00 PL3200/30V. 0/20 £1 45.00 1503NA 0.03°m basic £175.00 PL 154 0/ 159.0/4A £1 45.00 SCOPEX PL31000AOMODE DUAL (QMD) . 1504 0.08°n basic. True RMS £185.00 s:.,:.: - - - 14015 Dual 15 MHZ 5 tube Options: Carry case £18.00 2a30V0/IA oro/3002Aor0/60V0/1Aor0to TV '==aase:" SYNCH Z MOD Size 153 x 312 x 435 mm £325.00 1905A 5', digit intelligent multimeter 29 ranges ±30V0/IA £249.00 F6 As above plus fitted ImV. 0.01500 basic. Auto storage. Computing PL320 QMD As PL310 but £315.00 0.2HZ to 200 KHZ Function Generator £425.00 functions. etc. £325.00 twice current THANDAR EIGHT CHANNEL DIGITAL CAPACITANCE 2 year warranty METER SC 110A 10MHZ battery portable slim SCOPE MULTIPLEXER (UK C/P £1.001 32 x 26mm display. Many features. LEAFLETS DM358 Expands any 6M200 Bench portable. cope available for (UK C/P £1001 £165.00 most items scope to eight channels send SAE 6 ranges cover 1p i to OPTIONAL (Large digital or analogue signals. 25p for latest calaloguel 2500mfd. 4'. digit LCD. Carry case adaptor £5.95 AC £6.95 NICAOS £11.00 35MHZ BW £169.00 02°,a basic £89.00

Please add 15% VAT (UK only) I ALL PRICES SUPPLIERS OF ELECTRONICS FOR EVERY PURPOSE Export allow adequate CIF VAT ORDER BY POST OR PHONE 301 Edgware Road London. W2 Test Equipment, Audio, Communications 01-724 3564 Edgware Road. London, W2 Up to £ 1000 instant credit 404 Available through Lombard Tricity Finance Computers 01-402 6822 Equipment 01-724 0323 Components 01-7231008

CALL IN AND SEE FOR YOURSELF All mail to Cubegate Ltd, ist Floor, 406 Edgware Road, London W2 l ED

CIRCLE .59 FOR FUR'T'HER DE'T'AILS.

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 29

www.americanradiohistory.com 'ATLAS' - The complete Robotics Teaching System

By combining basic robotic control and sequence design with full test and diagnosis, L.J. Electronics have produced `ATLAS', a unique Robotic Teaching System.

Based around a well engineered polar type robot, the ATLAS system features:

Full test and diagnosis Sophisticated software that can be implemented on a remote L.J. microcomputer, including mimic and co-ordinate programming and 'CLARE' a robotic programming language.

The ATLAS Robot has - On -board microcomputer 5 degrees of freedom, plus one supplementary function Stepper motor control Teaching console with full editing functions

Send for details of the 'ATLAS' system and find out for yourself why its so unique. u

L.J. Electronics Ltd Francis Way, Bowthorpe Industrial Estate * New Work -Cell System Norwich NR5 9JA England 1985 Telephone: (0603) 748001 Telex: 975504 available early CIRCLE 25 FOR FURTHER DETAILS.

AA111 0.09 BCY70 0.16 BUM 1.40 184530 0.75 2N 3771 0.15 JAPANESE PCC85 0.42 LED 46119 0.09 BCV71 4.16 8U126 0.70 T04540 0.75 2N 3772 0.90 TRANSISTORS PCF80 0.S1 LED 3mm 44032 109 BCY72 0.16 80204 0.75 i06560 0.71 24.3773 1.10 25013 0.30 PCF200 1.35 RED 0.05 AC107 0.28 BD115 1.21 81.1205 0.70 T8A80X 0.35 24.4031 0.25 254104 1.32 PCF801 1.10 LED 3mm AC126 0.17 80124P 1.54 130208 0.75 TBABIOS 150 2N 4036 0.25 254198 0.22 PCF802 1.$7 PCFBN 115 YELLOW 010 M&BRADIO AC127 1.15 80124 1.10 002063 IN 784820 0.75 2N.4037 0.25 254203 030 T80920 AC128 0.15 80128 0.36 1301080 1.20 0.11 24.1443 0.16 250413 0.37 PCO207 LED 3mm 80326 24.4444 0I.N.07 4C1286 113 80131 0.25 0.15 16/1950 0.10 076 15B54 0.25 PELOS GREEN 0.19 AC1416 1.25 BU406. 5.85 18690X 0.N 24 5061 0.20 PL519 /14 THE NORTH'S LEADING USED TEST 0.23 80132 25871 0.72 AC112K 022 BD135 1.20 01/4071.76 TC4800 1.302N5294 0.30 208337 120 PGL82 8.63LEDSmm 405311 123 80136 0.21 BU408 1.00 TC4940 015 24 5296 0.30 258405 0.22 PCL84 e.54 RED 0.05 EQUIPMENT DEALER AC176 0.11 BD137 0.20 130500 1.10 1001170 0.90 24.6106 0.40 2SC460 021 PCLBS 035 4C1761t 24.6107 1.40 LED 5mm 0.20 80138 0.20 80526 014 1041412 114 2SC495 0.611 PCLN 055 YELLOW 010 AC187 015 80139 /.20 BY126 LN TDA2002 1.8 246109 0.40 21C733 0.49 PCL805 0.55 OSCILLOSCOPES AGIATE 0.20 80140 0.21 81127 0.81 7042003 LN 0.15 3N178 0.55 25C1181 1.10 PFL200 IEOSmm AC180 0.17 60144 0.14 BY133 O.N TOA2020 1.N 25CI112Y PL36 9.N Tektrorm 7N113 ON ,N 0.05 GREEN 010 ACI886 0.23 80150 LN 80164 022 TD42030 1.N PL504 465 100Mhz 5Mv Dual Trace 2 TBase C1350 00 2SC1279 124 ACY18 0.44 80157 0.38 BY176 0,86 TDA2522 IN 2SC1306 PLSOB 1.90 454 150Mhz51.4v Dual Trace 2 TEM. C795 00 N 914 0.02 1000.70 4CY19 0.48 80158 4.N 80179 LN 7042530 0.14 25C,407 453 50Mhz Dual Trace 2 TBase C495 00 6.4001 0.94 1.N 40142 0.N 80166 0.31 80782 0.32 1042532 0.75 /.41 7403 Oscilloscope Nam -Frame C550 00 6 10X2 0.07 25C,520 US 2288 40149 0.46 BD175 /.34 60184 0.12 7042540 0.70 PY540A 18611071e TM with Sc502 15Mhz Dual Channel Plug -In. 05503100Mhz Universal Counter. Dm502 N 60X3 2SC,969 1.NBRIDGE1.10 515 ADI61 /22 60177 1.34 80187 1.32 T042560 0.70 /W Mullimeter°DSO, Digital Delay to 99.999 Events C1750 00 N 40X4 0.07 25C2029 1.N RECTIFIERS 09131 A0162 8.22 BD179 0.32 131196 010 T0A2593 O.N N 40X5 0.07 2SC2078 1.14 HEWLETT PACKARD 40124 0.25 B0181 0.46 8Y206 0.11 14/50V 016 1824 0550.00 N 4006 0.07 20C21224 2.N MaIn-Frame AF125 0.25 BD201 133 81207 1.11 1042890 170 MEN IA/t00V 016 182C ...ern-Frame £350.00 N 4001 0.06 2SC2952 1.27 400MV 10/2000 0.15 AF126 4.25 80202 0.31 81223 1.72 TIP29 0.15 183A 4 Plug -In and 1825A Time -Base and Delay Generator 0895.00 N 4148 0.02 250234 0.37 07088 Rangge Channel AF127 0.25 80203 0.42 1316I0 1.15 T1P294 0.22 16/407V 0.21 Cosser CDU150 Duel,Trace 35Mhz E ISO 00 IN 256135 4.N 7W1s39V0O60 6F139 0.22 80204 0.42 TIP29C I0,5N5400 14/6070 0.23 . RHODE SCHWARTZ N.5401 0.10 1.50 AF739 0.22 80222 0.31 CA370 0M TIP30 0.16 1372ensn 14/6400 0.25 SHE SIgnal Generator 17-5.0 Ghz C85000 N 5403 0.10 1672M8371205 1.07 62861 Range A1112 1.70 80225 /.31 CA30N IN TIP314 0.24 2A/I001/ 1.35 VHF Signal Generator 25-480Mhz5LSV [17500 N 5403 0.11 0PC575 1.00 207lp3950120 26/20X11 0.36 01.113 1.101 80232 0.21 CA3089 1.54 Taw 014 Sweep Signal Generator 400-1200Mhz SWU C225.00 4.5404 1.11 45215 1.88 80237 /.21 CÁ3260 0.90 11P324 0.24 24/4000 012 UHF SIgnel Generator 300-1000 Mhz SDR C145.00 N 5405 012 40217 1.111 80238 1.24 CINO 0.27 T1P33 030 24/6401/ 0.54 Polyekop SWOB 1.5 -400 Mhz C125 00 4 5406 0.13 0.N 80433 1.20 T1P36 0.14 lü2A/8000 UHF Tesl Recervers280- 4 600 Mha C17500 4540] 0.13 0.66 47110 1.10 80437 0.38 14.11321 I.70 TIP41A 8.22 70CRE7S 34/40XV SELEKTOMAT Type USWV £195.00 4.5408 0.17 2 N 47102 60535 0.78 MJ2500 1.14 TIP41C 0.25 Bpin 1.46 34/440V 160 Stereo Decoder standard MSDC (225.00 1.N 2 .N AYtOfi 1.N MJ250I 1.10 14 pm O.N 3Á/600V 0.74 Watts C400.00 80536 0.74 TIP424 4.n 2 UHF Power Sgnal Generator SCRD 275-2750Mhz 05-50 .N 6A1740V 1N Frequency Syntheslaer XUA 30 Hz-30Mhz C400.00 80531 0.40 MJ2955 1.56 11P42C 6.25 16 pm ON MJ3000 1.16 040 VOLTAGE IBpin 0.12 207:25":11 6A/40XV U.OU Transmisslon Measure, Lme 75-305Mhz £350.00 BA145 0.10 B0538 0.40 TIP47 2764 1.75N 1423001 1.10 TIP48 REGULATORS 20 pm 0.14 254/100V Rellektmlelel300-420 Mhz C145 00 BA168 0.10 BOX32 1.N 010 4116 0. 13015454 60665 4.11294 0.30 11P49 tag 7803 0.35 22 pm 0,16 169 Unbalanced Standard Attenualor 0.1500Mhz 50011ms C50 00 0.N 0.14 6116 0.N 7812 0.35 pm 84151 0.12 6F1N 0.16 MJE30A 1.31 TIP110 /17 24 0.1/ 10326 0.N RECEIVERS MJE360 013 7815 1.75 88101 0.13 BF181 0.11 TIP112 0.07 28 pin O.N 1M380 O.N fIfCTROIYTIL COLLINS 390/A CommUll oallons Recelvel C37500 88103 0.16 Bf183 0.20 44E350 0.N TIP115 /.45 1618 0.36 60p1n 0.25 C30000 LM3B1 1.N d]0XUF16V RACAL RA 171 Communlcallons Recervel BB105B 0.11 BF1B4 0.14 MJE520 0.14 TIP1t] IN 7874 0.15 £300.00 L51709 DII0.30 CAN 9.20 RACAL RA17UA Communlcellons Recervei 882058 0.24 68185 0.14 4JE295511 1.11 TIP120 0.43 7905 C25000 035 LM123 0.32 EDDYSTONE 830/7 3000c- 300Mhz BC101 1.07 BF194 0.05 TIP121 0.41 7912 £35000 0.40 VALVES LM141 On0.15 Eddyslon0830/9 8C108 0.07 20195 0.N 0647 0.N T1P122 0.47 7915 WATKINS6 JOHNSTONE 10Hz-900Khz C250 00 0.40 DY81 0.57 LM741 BC109 0.07 BF196 0.07 OÁ90 0.07 TIP125 0.47 1918 /10 OY602 Met O.aS BCI15 0.1/ BF199 I.N 0091 0.07 T1P126 0.50 792d /16 MISCELLANEOUS OM LM3900 0.25 BCI18 0.11 BF200 111 00200 0.07 71P127 0.14 ECC82 La4 78L05 NE555 0.15 HEWLETT PACKARD BC1411 0.1/ BF257 1.11 04202 1.07 TIP3055 0.14 01/ ECC83 0.43 TRIFLERS 015000 NE556 0.40 431B Power Meter 6C141 0.19 128256 0.11 0C28 1.N 11P3054 0.14 181.12 0.21 ECC83 0.40 LP1195 C20000 140005e11 80524 Impulse Sound Levell Meter 6C142 0.19 BF359 0.11 0C29 4.80 TIP3055 0.07 781.15 0.20 ECC85 0.41 81855/ 2.75 [/7500 OJO 30464 Broad Band Sampling Vollmelel BCI43 0.19 61336 0.21 0C35 1.50 11581 0.15 74018 0.21 ECM 0.41 350 4150 SWR Meters C12500 74024 0.14 ECN84 1.57 B1655/ [15000 BC147 0.05 BF337 0.21 0C45 0.56 11590 4.15 34604 with 3482 DOM Plug -In BC145 0.05 Bf338 0.20 0071 0.14 T1591 CM ECLN 4.57 600 0.30 C19500 LM30XK 100 8Y1(55/ 644860-600v 1 5 emp PSU ECL82 125 13C149 0.14 61762 0.14 0072 0.14 1M71]K 210 645340-15v 200 amp 3 Phase C275 00 pN 290d 0.14 ECL81 0.61 600 0.30 BGIS] O.N 01422 O.í1 0C200 1.N 1.513170 101.1031 C400 00 242905 O14 IN ECL85 0.57 B0655/ 53634 Time plebes BC159 0.14 8F458 0.19 OCP71 1.M Timer 11 Ghz C500 00 207 2906 0.14 LM323K 1.20 ECLBfi OA9 840 0.32 RACAL 9908Counler 8C182 O.N 61459 0.19 ORP12 1.N 0150 00 0.9 LM723 0.72 MARCONI TF tea H/410Khz-720450 BFX29 0.20 2N.290] HBO 0.71 BY670r C250 00 BC182L 0.N ORP60 1.N 1BHG6C 5.10 RADIOMETER SMG1 Stereo -Generator 2N 2926 0.N EF85 4.34 500 0.29 8C183 1.14 BFX84 0.20 ORP61 1.N IBNOSKC Wayne -Kerr Loganlhm c LCR Bodge 13500 C295.00 2N.3019 O.N 5.21 EF89 0.43 BY670/ BGI83L O.N BF%BS 0.14 78001C 1.N MARCONI TF2604 Voltmeter to 1Ghz [12500 24 3063 0.11 EF183 145 500 0.7, BC186 11.06 218887 0.15 R20086 0.0024.3054 19001C 2.15 MARCONI X.Y [splay TF2212 £10000 0.14 EF184 O.SJ BY%]OI BCI07l I.N B1888 0.15 1120108 0.N 19NGKC X -Y [splay 812213.1 C25000 20 3055 0.32 1.70 807 0.36 MARCONI BC212 0.N BFY50 4.11 E1.34 114 FLUKE £45000 24 0055N /.e EY86 011 BY%71/ C195 00 BC2121 O.N BFYSI 0.14 5A556D 110 0M2151/311AGO Braze/down nTes el pN 3140 9.N 0.31 600 010 6C213 0.N BFY51 0.14 045570 1.10 E587 X -Y . C6500 O.N ADVANCE Recorder 6f156 0.25 24.3642 PC97 1,07 Wave-Ana yser £1S0 00 BC2131 0.N SN75N3N 1.e MARCONI5 8C214 11.06 87F57 0.25 9176013N 1M P111LpsPM6a56 ereo-Generlalo £13500 8C2141 1.N 13F164 0.25 91760239 1.e Please add 50p P&P and VAT at 15%. Govt. Colleges. etc. TEX SCAN Sweeper f1í500 VS30100Mht 811100 0.14 59780336 176BPulse-Generator 0150 00 BC237 0.07 1.58 orders accepted BRADLEY 85619 0.15 TELONIC Sweep -Generator Aude to 2000Mhz with 10 separate Plug-In s C850 00 BC238 0.07 547611011 O.M Quotations given for Large Quantities 85X20 0.15 TEKTRONIX Tune -Mark Generale, 2901 C150 00 BC300 0.16 5476115 0.71 80621 0.16 PI03508110w7daV s}Of delivery TEKTRONIX Square Wave Generator 106 [15000 6C301 0.11 S1176226 1.N C450 OD BC3D2 9.11 80626 0.16 5476221 0.8 All All valves are new and boxed TRAN DATA TESTER 353/352/351 AAS NEW brand-new Components. 8c303 0.11 80629 1.19 Ring for items not listed. We stock 3,000 items COMPUTER GEAR 6C321 111 82616 0.11 128070 0.52 Dale Recording [60 00 BC382 1.14 11106 0.114 1660660 0.42 8' Disk -[we C8500 5. SIEMENS FDD 100/S en C70 00 BC32B Ó.Ñ BT1106 .Ñ 14044630 1.76 TREND 800 R5232 Dot Mears Punter. GRANDATA LTD. TEXAS SILENT 700ASR PrInter Terminal [225 00 4100 00 i:4N0 12 THE BROADWAY, PRESTON ROAD NOVATION Acoustic CoPRI RS 232 6C3Y i:5N4 BT1tÓ iAA550 áié 9& BCV33 1.54 01/04 110 T001105 046 WEMBLEY, MIDDLESEX, ENGLAND All ribose pica. plu. V.A.T. 6 Cezripe 60106 an140 5 A.E. Elpuldee. 6CV<2 ñ:260 iéñ3é 066o Telephone: 01-904 2093 & 904 1115/6 BC056 016 9un0 1.10 180520 175 86, Bishopgate Street, Leeds, LS1 486 Telephone: 053235649 Telex: 932885 Sunmit

CIRCLE 12 FOR FURTHER DETAILS. CIRCLE 28 FOR FURTHER DETAILS. 1984 30 ELECTRONICS & WIRELESS WORLD DECEMBER

www.americanradiohistory.com MIMI CONTROLLER

by Peter Mimicontroller Nicholls Given the i/o and assembly -language facilities of a BBC model B microcomputer, developing a controller is no great problem but to have the computer permanently running say a central heating system is a waste. The economical 6502 Mimicontroller takes over such applications.

Many secondary schools and an may be to teach machine -code 2716 emulator* and programmed increasing number of primary programming but which are easily into an eprom for insertion into schools are realising that the mic- turned into controllers. Microp- the three -chip controller. The rocomputer is a powerful con- rofessor is perhaps the best- other two i. cs in the controller are troller. They are also discovering known currently available unit; an INS8060 microprocessor and that young people are strongly Kim, Acorn System One and INS8154 ram/p.i.o. device. Cost motivated by design tasks which MK14 have all come and gone. of this board was about £30. challenge them to use electronics For the teacher, the choice is As the cost of the main i.cs on to control hardware ranging from not an easy one. Microcomputers this original board has risen so model-maker's motors and offer high-level language - the cost of 65 -family processors N -gauge railways to mock-ups of which may in fact be no easier has fallen, and more schools have c.n.c. drilling machines. Inter- than machine code for the com- experience of 6502 machine code face units allowing a microcom- plete novice - but cost much than hitherto. The need to rede- puter to drive motors, lamps, more than 'minimal' systems. sign the controller was clear. At loudspeakers, etc., from an Microprocessor controllers run the same time I felt that being input/output port are now pro- only machine code but they come able to somehow make use of the duced by a number of companies at a price that is much more likely BBC microcomputer assembler and various attempts have been to allow a whole class to have would be a significant advantage made to produce control lan- hands-on experience. (this computer outnumbers guages which make it easy for Since 1979 I have been explor- others in schools). As well as the children of all abilities to, for ing the possibility of using mini- obvious advantage for the enthu- example, switch a bit on or off. mal dedicated machine-code con- siast who has outgrown hand - At the other end of the spec- trollers in the classroom and trials assembly of machine code, there trum there are microprocessor with a small three -chip design at is the possibility of tempting systems whose primary function Belper High School in Derbyshire teachers to have a go at machine have proved successful. Briefly, Peter Nicholls is East Midlands code for the controller was deve- *The author's eprom emulator was coordinator for Electronics and Control described in the September, October and Technology with the Microelectronics loped on either the Sinclair Radi- November 1982 issues of E&WW pages Education Programme. onics' MK14 or a purpose-built 83, 73 and 82 respectively.

An undrilled single -sided p.c.b. can be obained for £5.50 including postage and packing from PKG Electronics, Oak Lodge, Tansley, Matlock, Derbyshire.

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 31

www.americanradiohistory.com MIMI CONTROLLER i

*5V +5V 10n 2 10n To pin 40 on 6502 C3 T R2 K:> 3k3 3k3 8 T38 ,z 34 20 6fVFc sa KY 931 IRZ3 IiR ES PortA AO 9 38-35 7 9 ° Reset IC1 IRS0-RS3) 1C2 0I 100» 25 6502 ait' A3 6522 Port 13 ¡To pin 34 17 R/W 2 on 6522 W I070 CB1 DO 19 33 CB2 40 14 CA1 26 39 I}I CA2 23 25 42 CS1 1 1k8 39C 37 24 16 4 A15 xI A14 10p IC 14 A13 3 Y1 ó 1MHz 138

8 11 10 CK YO 15 '14 '11. 13 CK I07b 1C7c 13 A8 C7f 3

2 '14 %Il

74LSO8 pin 7 to ground All- *5V C9b 74L514 pin 14 to +5V 74LS32 .5V 18 *SV 24 Decouple using 10n between pins 7 & 14 A 2 AO AO 5-7 ó7 8-1 08 2322.19 IC5 IC6 Ay Ag 7-15 17i5 A1 C9d 2114 2114 óE D4 E 14 14 IC4 4 11 11 2716 D3 CS Rl47 C5 RN 18 10 e 1C Do 9,10,11 13-17 D7

2 IC8^12

1 '32 13 Mimicontroller is designed to code control using a computer using one of the several eprom puter and controller, there should emulate BBC microcomputer that they are already familiar programmers available for the be no problems. i/o in control applications. with. computer, and transferred to To prevent bus contention Software is developed and Using the assembler to help Mimicontroller. between the different memory tested using the computer's people write their first bytes of The crystal, IC7b, R4 and C4 and devices, it is preferable to stobe assembly -language and i/o machine code bridges a concept- part of the 6502 produce inverted memories with the CK clock. By facilities then transferred ual gap which may otherwise be clock signal MK and IC7c a non - feeding CK into or gates ICBac, to a 2716 eprom for use in too large; thus Mimicontrollerwas inverted clock for the 6522 the chip -select signals to IC5 6&4 Mimicontroller. Ports A and B developed. timers. The BBC microcomputer respectively are only allowed low and control lines of the 6522 has a 2MHz clock whose fre- when CK is high, provided of v.i.a., top left, act as those on The circuit quency is halved through a com- course that IC3/9, have selected the BBC microcomputer. plex system when certain mem- the device in question. In a simi- Simplicity of the controller can be ory devices are accessed. lar way,_ IC6b strobes read/write seen in the circuit diagram - Because of this it is virtually line RN using CK. components, including zero - impossible to design a simple Gate IC7a, CI and R1 form the insertion -force socket for the controller that will mimic the power-on reset circuit; 74LS14 eprom but excluding p.c.b., cost computer in respect of software Schmitt inverters are used solely less than £20 which makes it timing. Memory i.cs rated at to give a short rise time to the attractive for school use. More 350ns are significantly cheaper reset signal. Time constant of R1, relevant to most readers though than faster ones -a further rea- C1 should not be shortened. is that Mimicontroller opens up son for not attempting to clock the The rest of the circuit produces the possibility of using the BBC Mimicontroller above 1MHz. the address map. It would be pos- microcomputer as a development The 6522 versatile interface sible to assemble code for any tool for all sorts of applications adapter, v.i.a., has elaborate tim- 6502 system using the BBC mic- from central -heating control ing facilities, however, and Mim- rocomputer, but it's a significant upwards but without committing icontroller's 1MHz clock is the advantage to be able to test the the computer to the actual job of same as the microcomputer's software by running it on the controlling the application. Once 6522 clock. If software timing/ computer, modifying it if neces- the code has been developed, it is delay loops are avoided and the sary, before committing it to programmed into a 2716 eprom, v.i.a. used instead on both corn - eprom for use with Mimicon- 32 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com MIMI CONTROLLER

troller. Relevant addresses not have access to the terminal, List 1. Simple clock program counting seconds on two within the microcomputer are and is discouraged in the User seven -segment displays may be used to test Mimicon- 0070-008F page -zero ram Guide. troller. (reserved for user) Mimicontoller's board (details 0100-01FF 6502 stack later) carries 1Kbyte 10 DDRB=&FE62:ACR=&FE6B:PB=FE60 of ram 20 IER=&FE6E:INFR=&FE6D 0200-27FF area chosen for (IC5,6) selected by the Yo output of 30 T1CL=&FE64:T1CH=&FE65 program IC3, giving 256 bytes of page -zero 40 FOR PASS=O to 3 STEP 3:P%=&2000 FE60-FE6F 6522 v.i.a. ram. A control program can of 50 [OPT PASS course use all of this and the 60 SED:LDA#&FF:STA DDRB One other point to bear in mind is gen- 70 LDA#&00:STA ACR:STA IER that the processor loads its reset eral-purpose ram area of 512 80 .JOE:STA PB vector and interrupt vectors from bytes between 0200 and 03FF but 90 LDX#&64 FFFA-FFFF in memory. Since the BBC microcomputer only 100 .BILL:LDA#&10:STA T1CL guarantees not to tamper with 110 LDA#&27:STA T1CH the programmer needs to be able 32 120 .SAM:LDA INFR:BEQ SAM to store these vectors in the top user bytes (0070-008F). By the 130 DEX:BNE BILL six bytes of eprom, address -bus time the control routine is called, 140 CLC:LDA PB:ADC#&01:JMP JOE states FFFA-F must be decoded the computer will have appropri- 150 ]NEXT into the eprom area 27FA-F. ated some of the stack for its own Three -to -eight -line decoder use. In other words, fewer than IC, and gate IC7d select the 6522 256 bytes will be available in the List 2. This variation of List 1 illustrates interrupt use. for exactly half of the possible 16 computer but this is more than byte blocks between E00x and enough for most amateur control 10 DDRB=&FE62:ACR=&FE6B:PB=FE60 software. 20 IER=&FE6E:T1 CL=&FE64:T1 CH=FE65 FFFx. In this way the 6522 is 30 FOR PASS=O TO 3 STEP 3:P%=&2000 selected for FE60-F but inhibited 40 [OPT PASS for FFFO-F when the processor is Testing 50 LDA#&FF:STA DDRB loading a vector. 60 LDA#&CO:STA IER To test the board List 1, a simple 70 LDA#&40:STA ACR Output Y1 of IC3 is low for all 80 LDA#&10:STA T1CL addresses between 2000 and timing/clock program, can be run 90 LDA#&27:STAT1CH 3FFF thus selecting the eprom, with a pair of seven -segment dis- 100 CLI:LDX#&64 IC4. In other words when plays connected to port B (the 110 .WATT:JMP WAIT:JMP WAIT user port) through two 74LS47 120 ] assembling via the BBC compu- 130 P%=2100 ter, the eprom can be considered i.cs and current -limiting resis- 140 [OPT PASS as residing in any of four 2Kbyte tors. If this program is run on the 150 LDA T1CL:DEX:BNE SKIP blocks, 2000-27FF, 2800-2FFF, BBC computer by a call to loca- 160 LDA PB:SED:CLC:ADC#&01:STA PB tion 2000 (CALL&2000) the 170 LDX#&64 3000-37FF or 3800-3FFF, 180 .SKIP RTI chosen by the user. seven segment display will count 190 ]NEXT Gates IC9a,b,d and IC71 cause IC4 seconds (approximately). Load 200 ?&206=00 to be the reset vector into the computer 210 ?&207=&21 selected when the most 220 CALL&2000 significant byte of the address is by instruction at line 160 (210916 in F9, FB, FD or FF. Unless there is ?&27FC=&00 assembled code) would be more an error in the software, this can ?&27FD=&20 economically placed in the first only occur when the processor is block of code at, say, 201C or line trying to load a vector. In this way and transfer the code to eprom. 45. In the microcomputer it is FFFC, for example, on the add- The software should give an rendered ineffective by the ress bus will cause the contents of identical count rate on Mimicon- operating system, which tampers 27FC to be placed on the data troller. with the processor status register bus. Vectors may therefore be List 2, a variation of List 1, when the is serviced. located so illustrates interrupt use. The pro- interrupt In summary, use the assembler 27FD reset gram is put into an endless loop high -byte and board with abandon when no 27FC reset low -byte until an interrupt occurs, i.e. interrupts are involved. The com- 27FB NMI high -byte when timer one times out after puter will not only assemble the 27FA NMI low -byte 10ms. The loop count in the index code but also run it so it can be 27FF IRQ high -byte register (X) is decremented in the tested. Be aware though of the 27FE IRQ low interrupt routine at location byte extent to which the computer 2100, and the display on the port Interrupt use on the BBC micro- uses interrupt and do not be sur- changed if necessary. Lines 200 computer is complex, but it is prised if it will not run code which and 210 load the interrupt vector possible to use the normal facilit- involves interrupts. Software into the IRQ2V locations in the ies of the 6522, interruptig using interrupts can of course be microcomputer and line 220 runs through IRQ, as long as the inter- assembled and transferred to the program. To transfer the pro- rupt vector is loaded into the eprom for testing directly on gram to eprom, first set up the computer at 0206 (low byte) and Mimicontroller. IRQ vector using 0207. The controller has been made Mimcry is likely, but not cer- ?&27FF=&21 on a p.c.b. measuring 160 by tain, to be exact as the servicing ?&27FE=&00 100mm. Careful design allows a of an interrupt - even from the single -sided board with a v.i.a. in an assembly-language Again, identical operation should manageable number of links. program - will bring the micro- be seen on Mimicontroller. Current drawn by the circuit is computer's operating system into When the software is run on the about 350mA so it can be driven action, which may interface with microcomputer, the sound gener- by NiCd batteries and used on a the user's routine (see Lists). ator comes into action after about `buggy' for example. Use of Using NMI (non-maskable inter- 25s - one illustration of the 65CO2, 65C16 and 2114L devices rupt) is substantially more diffi- interaction of interrupts with the reduces power consumption by a cult, not least because one does system. Secondly, the SED factor of four, but increases cost. ELECTRONICS & WIRELESS WORLD DECEMBER 1984 33

www.americanradiohistory.com INTERFACING

Continued from Page 20 then if the message 'SYNC sion of a low-pass filter consisting initialization of the program con- rently programs logical colour ERROR' appears, press function of a 1k52 resistor and 68pF capaci- siderably since it no longer has to two to actual colour eight (flash- key one. This sends a pulse tor in the output of one of the mul- calculate frequencies of the ing black/white). Removing it will through CB, to step IC,o so press tiplexers. equal -tempered scale. leave logical colour two at its the key as many times as is neces- Once the program has been No attempt has been made to default actual colour, yellow, in sary to regain synchronization. run, the assembler section can be make the program `tube' compati- any case leave the second half of Alternatively, a hardware reset removed if the assembled version ble, the main reason being that this instruction intact. This sets can be instituted by including a is saved as machine code using the software is still of an experi- logical colour one to black. Curi- push switch to connect pin two of *SAVE. After running the pro- mental nature. ous effects will occur without it. IC,o to V« through a lk62 resistor. gram press the escape key then There would be no difficulty in Line 2690 checks input for a Software synchronization type *SAVE 5500 making the program compatible synchronization error which, if could be made completely auto- +300. Lines 270, 360-380, 420- with OSBYTE calls, though these found, causes printing of a mes- matic by a subroutine that sent a 440 and 510-2660 can then be appear to operate some 20 times sage and stops the program. One pulse through CB, whenever the deleted from the program and the slower than direct addressing of way of dealing with this is to add first byte read was not FF. Some shorter version saved. Line 390 the devices. Whether this would these lines. synchronization problems were must be then changed to be of any significance depends on 245 CLS experienced initially with the pro- NEXT: NEXT: NEXT and the the application. 90*KEPI ?&FE6C-&DOIM totype due to switching tran- instruction 165 *LOAD added. This speeds up

CIRCUIT IDEAS

Vout

Twin -T filters pass circuit is Attentuation of the filter for k=1/20, 40dB for k=1/ depends on the choice of k. For and 46dB for k=1/100. It is> V.,u, (1+4sCR+ s2CZR2) These band-pass and all -pass example, at the resonant pointless to choose a value fo V,,, filters use twin -T networks. (1+4skCR+ s2C2R ) frequency w,,, attenuation is smaller than about 1/50. Transfer function of the band- where k=R,/(R,+RZ). 26.02dB for k=1/10, 32.04dB Transfer function of the a pass filter is - 1-4sCR+s2C between about one and two- cycle to vary between 0 and V,n ( s "+s2C2.¿, oltage thirds of the supply voltage. 100%. frequency w controlled duty Varying the control at the E.H. Rice At the resonant comparator's non -inverting Exeter output voltage of the twin -T input causes the output duty Devon network is zero and output of ycle the op -amp is -V,,,. The twin -T Forming part of an automatic network with fixed capacitanc voltage regulator for an values is suitable for direct alternator, this simple circuit implementation as an i.c. wit"" gives a rectangular output many useful appl'- . . waveform with a duty cycle Kamil Kraus between 0 and 100% depending Rokycany on the control voltage. Frequency is determined by R, and C, and is independent of the mark/space ratio. The 555 is configured as an Further equations relating t astable circuit, Tr, providing a this idea can be obtained byá constant current charge for C,. sending an s.a.e. marked T This results in a linear ramp at T filters to E&WW's Editorial the input of the voltage comparator which varies offices. WORLD DECEMBER 1984 4 ELECTRONICS & WIRELESS

www.americanradiohistory.com NEW GENERATORS

NEW TG501 FUNCTION GENERATOR .005Hz to 5MHz; sine, square, triangle, ramp, pulse and haverwave waveforms; free -run, triggered or gated modes; variable start/stop phase, 19:1 symmetry range; variable DC offset; variable 501/ output; TTL output; external sweep mode. NEW TG502 SWEEP/FUNCTION GENERATOR Main generator features as TG501 plus internal sweep generator; 1000:1 linear or 10,000:1 log sweep range; precise dial -and -enter setting of sweep limits; marker with variable duration and out -of -range indicator; variable sweep rate; single sweep mode; sweep reset and hold; sweep and pen -lift outputs. NEW TG503 PULSE/FUNCTION GENERATOR Main generator features as TG501 plus normal, double and delayed pulse modes; pulse width variable from 5Ons to 50ms; delay variable from 100ns to 50ms; 10MHz capability in double pulse mode; complement mode; symmetrical, positive -going or negative -going outputs with adjustable baseline. For further information contact: Thandar Electronics Ltd, London Road, St. Ives, Huntingdon, Cambridgeshire PE17 4HJ Telephone: (0480) 64646 Telex: 32250. thandar ELECTRONICS LIMITED CIRCLE 26 FOR FURTHER DETAILS. What the competition hasn't been waituna for. Latest version of Forth for the BBC 16k Eprom type 27128 (Is not rehashed Forth 79 Code)\ for CD BBC Multi -tasking operating system Unique Stack Display Utility SOFTWARE Real -Time use. MULTI - FORTH 83 Micro /for

Here's the Forth Eprom for the BBC Micro that makes all others extensive Manual (170 pages plus) and at f45+VAT it is superb value. out of date. Order it using the coupon adding £3.45 p&p (£6 for Europe, £12 It's Multi -Forth 83 from David Husband who has built his outside) or if you want more information, tick that box instead. Either reputation for Quality Forth products with his ZX81-Forth ROM, way, it will put you one step ahead of the competition. Spectrum Forth -I/O Cartridge and now New Multi -Forth 83 for the BBC Micro. This is not rehashed Forth 79 Code, but a completely new Please send me Multi -Forth 83 for BBC Micro £45+VAT De -luxe System inc Disc 180 + VAT version of the Forth 83 Standard. It's unique in that it Multi -tasks, and Cheques to Skywave Software Readers' A/C (or enter Visa No ) therefore the user can have a number of Forth programs executing SI= simultaneously and transparently of each other. Illllll Please send me more information Multi -Forth 83 Multi -Forth 83 sits in the sideways ROM area of the BBC along Name ZX81-Forth ROM W W with any other ROMs in use. It is compatible with the MOS, and Address Spectrum Forth -I/O Cartridge specially vectored to enable a system to be reconfigured. It contains a Standard 6502 Assembler, a Standard Screen Editor, and a Unique Stack i Display Utility. Post code With this Forth, David Husband has provided the BBC Micro with SUBJECT TO AVAILABILITY. FOR I.0 0.S ONWARDS. Send to Skywave Software, 73 Road, Bournemouth, capabilities never before realised. And being 16K rather than 8K is Curzon BH1 4PW, Dorset, England. Tel (0202)302385 SOFTWARJ twice the size of other versions. Multi -Forth 83 is supplied with an MULTI -FORTH 83 FOR THE BBC MICRO CIRCLE 7 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com Minimum 'SPECIAL VAT PAID r VALVES Order £1 QUALITY PRICES MAY VARY 0.90 A7065 1.40 EF91 1.60 PL36 1.10 1A3 1.40 6BW6 6.20 6Y6G 0.70 INDUSTRY STANDARD A2293 8.80 EF92 2.90 PL81 0.85 1L4 0.80 68W7 1.80 6Z4 724 1 90 A2900 13.75 EF95 0.95 PL82 0.70 155 0.80 6C4 0.70 2.90 ARB 0.75 EF96 0.60 P183 0.60 1S4 0.45 6C6 1.20 9D6 ARP 0.70 EF183 0.80 PL84 0.95 1S5 0.45 6CH6 8.20 11E2 19.50 ATP4 0.60 EF184 0.80 PL504 1.00 1T4 0.45 6CL6 2.75 12A6 1.00 672H 3.90 0.75 PL508 2.l0 1U4 0.80 6CW4 8.50 12AT6 0.70 EF812 0.85 CV31 1.40 EFL200 1.85 PL509 5.85 1X2B 1.40 6CX8 3.80 12AT7 12AU7 0.60 DAF96 1.25 EH90 0.85 PL519 5.85 2X2A 2.50 6CY5 1.15 0.95 DET22 28.50 EL32 1.10 PL802(SE) 2.95 3M 0.70 6D6 0.95 12AU6 12AX7 0.65 DF92 0.80 EL34 1.80 PY80 0.70 3AT2 3.40 6F6 1.60 128A6 0.90 DF 0.70 4.55' PY81/800 0.85 3828 12.00 6F6GB 1.10 DH76 0.75 EL37 5.20 PY82 0.65 19.50' 6F7 2.80 128E6 1.25 1213H7 3.00' m O192 0.60 EL82 0.70 PY88 0.60 3D6 0.50 6F8G 0.85 18.95 DV86/87 0.65 EL84 0.80 PY500A 2.10 3E29 19.00 6F12 1.50 12E1 12J5GT 0.55 DV802 0.70 EL86 0.95 QQV03/10 3.20 3S4 0.70 6F14 1.15 0.70 E92C 2.80 EL90 1.00 7.50' 4B32 18.25 6F14 1.30 12K7GT 0.80 E180CC 8.25 EL91 6.50 QQV03-20A 5R4GY 2.20 6Fr7 3.20 12K8GT 12Q7GT 0.60 EA76 2.25 EL95 0.80 21.50 5UAG 1.40 6F23 0.75 125C7 0.65 EABC80 0.80 EL504 2.70 QQV03-25A 5V4G 0.75 6F24 1.75 EB91 0.60 EL509 5.75 36.50 5Y3GT 0.95 6F33 10.50 12SH7 0.65 17.80 12SJ7 0.70 EBC33 1.15 EI519 6.90 QQV06/40A 5Z3 2.80 6FH8 12507 1.45 EBC90 0.90 E1821 8.20 22.50/45.50 5Z4G 0.75 6GA8 1.95 0.85 0.60 E1822 9.995 0V03-12 4.20 5Z4GT 1.05 6GH8A 1.95 12S7GT EBFBO 0.70 EBF83 0.60 ELL801SE) 2.80 SP61 1.80 6/30L2 0.90 6H6 1.60 12Y4 13D3 2.80 EBF89 0.80 Em80 0.85 1721 32.20 6A87 0.70 6JU6 5.85 13D5 0.90 EC52 0.65 EM87 1.30 1722 29.50 6AC7 1.15 6.14 1.35 19AQ5 0.85 EC91 4.40 EY51 0.95 UABC80 0.75 6AG5 0.60 6J4WA 2.00 19G3 11.50 Filters EC92 0.85 EV81 0.65 UAFA2 1.38 6AH6 1.15 6J5 2.30 8.50 ECC81 0.85 Ey86/87 0.60 UBF80 0.70 6AK5 0.65 6J5GT 0.90 9G6 19H5 39.55 ECC82 0.60 EY88 0.66 UBF89 0.70 6AK8 0.60 6J6 0.85 20D1 0.80 ECC83 0.65 EZ80 0.70 UCC84 0.85 6AL5 0.60 6J6W 2.80 1.30 ECC84 0.60 EZ81 0.70 UCC85 0.70 6AL5W 0.85 6JE6C 4.85 20E1 4.85 20P1 0.65 ECC85 0.60 GM4 5.90 UCF80 1.30 6AM5 4.20 6JS6C 25L6GT 1.60 Prices ECC88 0.80 GY501 1.30 UCH42 1.65 6AM6 1.50 61(7 0.80 New Low 0.75 1.05 UCH81 0.75 6ANBA 2.50 61(08 1.50 25Z4G ECC189 0.95 GZ32 6KD6 4.50 GZ33 4.20 UCL82 0.95 6A04 4.40 35W4 0.80 ECC804 0.90 6L6M 2.80 0.85 GZ34 2.75 UF41 1.35 6A05 1.00 85A21.40,2.55' ECF80 6L6GC 3.70 ECF82 0.85 GZ37 3.95 ÚF80 0.95 6AQ5W 1.80 807 160/2.40' 6L6GT 1.80 21.80 ECF801 1.05 KT66 14.50 ÚF85 0.95 6AS6 1.15 812A 6118 0.70 ECH34 2.25 KT81 7.00 ÚL84 0.95 6AS7G 4.95 813 in OEM Quantities 61D20 0.70 1.20 KT88 23.00 ÚM80 0.90 6AT6 0.90 28.50/68.50' ECH42 6LQ6 4.85 ECH81 0.70 ML4 2.80 UM84 0.70 6AU6 0.90 8298 24.00 1.30 ECH84 0.80 ML6 2.80 UY82 0.70 6AV6 0.35 607G 832A 8.90 6SA7 1.80 5.05 ECL80 0.70 N78 9.90 ÚV85 0.85 6AX4GT 1.30 866A 0.75 0A2 0.70 VR105/30 1.25 6AX5GT 1.30 6SG7 1.50 866E 9.80 ECL82 66.17 1.50 ECL85 0.80 0132 0.80 VR150/30 1.35 6BA60 931A 19,80 From 0.70/1.20' 6SK7 1.40 954 1,20 Stock 1.80 ECL86 0.90 PCL82 0.95 X66 6SL7GT EF37A 2.15 PCL84 0.90 X61M 1.70 6649 3.45 0.85 955 1.20 6BE6 6SN7GT 1.60 1.20 EF39 1.50 PCL86 0.75 Z759 19.00 956 6507 0.95 4.83 EF80 0.65 PCL86 0.75 2749 0.75 0.65/120' 5763 6BG6G 1.60 6SR7 4.60 1.95 EF83 3.10 PCL805/85 0.95 28000 3.45 6060 1.30 6V6G 1.50 EF85 0.60 4.30 2801U 3.75 6BJ6 6080 5.30 PDL250/510 6B07A 0.85 6V6Gt 1.30 EF86 0.75 1.10 2803U 16.00 6201 5.20 29007 2.45 6BR7 4.80 6X4 1.50 9.50 103 EF89 1.60 2.80 6146 R5630 Full -duplex 300 baud, 6X5GT 0.85 61468 9.50 in 16 pin DIP. VALVES AND TRANSISTORS NEW PYE 8068 12.50 compatible filter Telephone enquiries for valves, transistors, etc: NT 9001 0.95 retail 749 3934, trade and export 743 0899. EQUIPME 9002 0.95 FIELD TELEPHONE, CABLE TYPE D10 & SPARES 9003 0.95 FIELD TELEPHONES TYPE 'J'. Tropical. in metal cases. HARNESS "A" & "B" CONTROL U 10 -line MAGNETO SWITCHBOARD. Can "J1" "J2." Microphones No 5, 6, 7 connectors, R5631 Full -duplex 200/300 baud, V.21 work with every type of magneto telephones, frames, carrier sets, etc. POSTAGE: £1.£350p; 03-05 608; E5-£10 BOp; £10-£15 £1.00; £15-020 £1.50 CCITT compatible filter in 16 pin G oldhawk Rd, LondonWl2 DIP, -pin compatible with COLOMOR (ELECTRONICS LTD.)170 pin -for Tel. 01-743 0899 or 01-749 3934.0pen M onday to Frid ay 9 a.m.-5. 30 p.m. R5630.

R5632 Full -duplex 1200 baud, 212/V.22 combo filter. Z80A MICRO -CONTROLLERS

4MHz Z80A CPU 4K EPROM - 2K supplied with MCV2.0 4K Battery backed RAM - 2K supplied R5633 General purpose programmable 4 v Z8OA PTO's (641/0 lines) filter array for full -duplex 103, Z80A CTC Standard 100mm o 160mm Eurocard V.21, DTMF and Videotex. Cost effective prices (£94.04-10 off) includes all connectors, manual etc.

Designed to meet the power and flexibility of today's stand - alone micro -controllers, the GNC CUB makes full use of the powerful Z80 family IC's. Micro -controllers are available with up to 64K RAM, 8K EPROM, RS232 etc. R5626 Mask programmable to your Manuals include circuit diagrams and.assembly language listings. No ULA's, PAL's or other funnies. Write, phone or circle to find out more about our powerful range of Z80A micro -controllers and multi - tasking specification. software. PRICES CUB (built & tested) £103.44 GNC ELECTRONICS Bare board £2..00 Little Lodge, Hopton Road, Reticon also provides a wide variety of other stan- Manual (free with CUB/board) £3.50 Thelnetham, Diss, Norfolk. IP22 1JN. dard and specialised custom filters and signal Please add £1.00 for P&P plus V.A.T. Tel, Dios (0379) 898313. proven NMOS processing devices using Reticon's CIRCLE 65 FOR FUR'T'HER DE'T'AILS. Switched -Capacitor Technology. Contact us on your needs at Chicago (312) 640- 7713; Boston (617) 745-7400; Japan 03-343-4411; Toroidal England (0734) 788666; Germany (089) 928-060. Transformers as manufacturers we are able to offer a range of quality Toroidal Transformers at high competitive prices and fast delivery. EGG itRE'IICON® Mail Order Price List Vss* 30VA 6.54. 50VA 8.36. 80VA 9.15.120VA 10.55.160VA 11.98. 225VA 15.61. 300VA 17.19. 500VA 22.33. 625VA 27.96. 750VA 31.05.1 KVA 41.40. price includes pi-p & vat. Available from stock in the following voltages:- 6-0-6, 9-0-9,12-0-12, 15-0-15.18-0-18, 22-0-22.25-0-25, 30-0-30, 35-0-35,40-0-40, 45-0-45, 50-0-50, 110,220,240 (max- 10 amp). Primaries 240, 220, 120 volt please 34/35 MARKET PLACE, WOKINGHAM, BERKSHIRE RG11 2PP state which. Telephone: Wokingham (0734) 788666 Telex: 847510 EGGUK Quantity Prices and delivç on request (we also manutacture conventionaltype transformers) Airlink Transformers. AIR Unit 6, The Maltings, Station Road, LINK Sawbridgeworth, Herts. Tel: 0279-724425.

CIRCLE 48 FOR FURTHER DETAILS. CIRCLE 66 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com TELEVISION

HDTV or EDTV? by Tom Ivall Extended definition television - building up picture resolution gradually, flexibly and compatibly - is being considered as an alternative to all-out high- definition television on completely new standards. This report outlines some of the current investigations into ways of achieving higher definition pictures, as described in papers at IBC 84, the 10th international Broadcasting Convention at Brighton.

As long as the broadcasters conti- sion standard. Picture -source It is also assumed there will be nue to produce a succession of and receiver -display standards available large -screen displays of technical innovations, like rabbits need not be the same as the at least 1 metre diagonal, with a out of a hat, to add to their sys- standard used for transmission wider aspect ratio than that of tems, they will be relatively safe over the air. Some of the propo- existing tv receiver screens - from the rival methods of distri- sals for 'enhancing' picture qual- probably about 5:3. This wider buting television programmes. ity in this way were outlined. display, according to K.H. Pow- Transmission standards, colour, Since 1982 several things have ers of RCA Laboratories, has additional channels, teletext, happened which have brought proved to be more pleasing to stereo sound, have all in their these proposed enhancement viewers than 4:3, increasing their turn provided new opportunities much closer to reality. In 1983, feeling of involvement with the for selling more consumer equip- for example, a number of Euro- programme material. ment and advertising time. pean broadcasters showed their Beyond this common ground To judge from papers and involvement by putting on there are differences of engineer- demonstrations presented at the demonstrations of HDTV at the ing opinion on how higher defini- recent International Broadcast- Montreux television symposium. tion services should be intro- ing Convention, the transmission Then in January 1984 the Japa- duced. As pointed out by K.H. standards, and other related nese launched an operational Powers, there are several options standards, are now coming round direct broadcasting satellite available for utilising the extra for another rejuvenating pick- (DBS) which was intended even- bandwidth offered by DBS chan- me-up. "High definition" is on tually to carry experimental nels - increasing the horizontal everyone's lips again - as it was transmission derived from NHK's resolution and/or the vertical res- once before, in 1936, when used provisional 1125 -line HDTV olution and/or the aspect ratio, to distinguish the UK's then new standard. (In the meantime this and the possibility of using time 405 -line tv service from earlier satellite has had transponder multiplexed analogue compo- 30-, 150- and 240 -line experi- faults - see September issue, nents to avoid the cross -colour, mental systems. p.14.) cross -luminance and noise The previous WWreporton the And during this two-year impairments experienced with biennial IBC (December 1982 period the European Broadcast- composite signals. issue) focussed on the great signif- ing Union (EBU) has officially But the main difference of icance to tv broadcasters of the recommended a DBS transmis- approach seems to be: 'straight' then newly established CCIR digi- sion standard. Based on a propo- HDTV versus 'extended defini- tal coding standard for studio sal from the IBA and called tion' television (EDTV). Is it bet - equipment. Many realised that C-MAC/packets, it is expressly this internationally agreed stand- designed to allow future compati- Lines Fields Line scan Improvements or cures ard, based on luminance and ble higher definition transmis- Interlace per per factor frequency Large area Interline Line Static chrominance components rather sion. picture second kHz flicker twitter crawl raster than on the composite colour sig- All the work now being done by 625 50 2:1 15625 NO NO NO NO nal, would open up all kinds of broadcasters and manufacturers 625 50 1:1 31.25 NO YES* YES NO t extra possibilities for improving seems to be based on certain 1250 50 2:1 3125 NO YES* YES YES picture quanlity. assumptions. The first is that 625 100 2«2:1 3125 YES NO NO NO 625 100 21 31: 25 YES YES* YES NO Using the latest digital pro- higher definition services will be 1250 100 4:1 3125 YES YES * NO NO cessing and storage technology, provided through 12GHz DBS 625 100 1:1 62 5 YES YES YES Not video information could be 'pre- transmissions in 27MHz or 1250 100 2:1 62.5 YES YES YES YES is processed' at the studio and 24MHz f.m. channels. Another * Subject to interpolation algorithm -processed' at the receiver that sufficient money will be 'post tThere is, however, some subjective improvement without any constraint from the available to meet the considerable due to sequential display nature of the composite transmis- costs. ELECTRONICS & WIRELESS WORLD DECEMBER 1984 37

www.americanradiohistory.com TELEVISION

complete separation between is no longer line -sequential, thus luminance and chrominance improving the vertical chromin- High quality Large screen components that overcomes the ance resolution. Display 625 line wide aspect cross -chrominance, cross - The Philips researchers claim upconversion source ratio luminance and noise problems of that, in conjunction with over - composite transmission signals. sampling and non -interlaced dis- To provide the 25% extra pic- play scanning, such coding sys- ture information need for a 5:3 tems allow transmission of sig- aspect ratio over a 4:3 ratio, nals with up to 390,000 picture E xtended MAC some additional line time is elements in an 8.4MHz channel. decoder obtained from the field blanking This compares with conventional interval and some from the data PAL resolution of 147,000 pix- period, still leaving enough audio els. A further system being inves- data for two sound channels. But tigated, using two DBS channels, extra time compression is needed offers an overall resolution of Extended Conventional Small screen at the edges of the picture to 780,000 pixels. MAC MAC 4.3 aspect coder decoder ratio achieve the full 5:3 ratio. As part of an international To increase the vertical resolu- research effort on world-wide DBS tion, the display at the receiver is standards for HDTV picture channel up -converted to sequential 625 - sources, the BBC has been study- line scanning (non-interlaced), ing the large -screen display at the Fig.1. IBA`s compatible period. The baseband for trans- thus providing an apparent 40% receiver - a logical starting approach to higher definition mission via the satellite is then increase in this resolution. But point for investigating HDTV sig- television using extended 8MHz wide. moving parts of the picture need a nal parameters. I. Childs and A. MAC in a C-MAC/packets In the receiver a 4 -field mem- motion -adaptive conversion Roberts of the BBC Research DBS channel. Other ory is necessary to store the sub- technique to avoid blurring Department described how they researchers think there is Nyquist samples distributed over (described by T.J. Long and G.J. have used a conventional picture further benefit to be obtained the 4 fields at the transmitting Tonge in another paper). Hori- tube to simulate one quarter of a by starting with a high line - end. Pictures are reconstructed zontal resolution is increased by large -screen display. number HDTV picture source by interpolation from these to using a greater than normal base - To test the belief that 625 -line and down -converting to 625 give a bandwidth of 25MHz for band bandwidth of about 11MHz, pictures can be significantly lines for transmission. stationary parts of the scene and which allows an uncompressed improved by display processing 15MHz for moving parts. luminance bandwidth of over alone, regardless of the transmis- Because the basic process intro- 7MHz. sion standard, they tried a num- duces unacceptable blurring on Figure. 1 shows how E -MAC ber of scan up -conversions with slow, uniform movements in the would be used in compatible different line numbers, scanning scene, a motion compensation approach to high definition. The frequencies and interlacing fac- ter to establish a new high -reso- technique is added. This uses viewer can use either a conven- tors (including 1:1, or sequential lution system in one go, or gradu- inter -frame comparisons at the tional C-MAC/packets decoder scan). The results obtained are ally to extend the resolution transmitting end to produce a sig- and ordinary televison set or an shown in the table. capabilities of existing 625 -line nal which is used at the receiver to E -MAC decoder with scan up - The authors conclude that dis- and 525 -line systems while pre- shift the read-out address of the conversion and a large, wide - play up -conversion can substan- serving compatibility? 4 -field memory accordingly. aspect display screen. The con- tially remove the major limit- As an example of the 'straight' The NHK transmission stand- ventions C-MAC/packets receiv- ations of 625 -line displays (right- HDTV approach, E. Kimura and ard is broadly comparable with ing equipment simply ignores the hand column headings in table). Y. Ninomiya of NHK Research the EBU-recommended DBS extra information provided by the But there is a problem with scene Laboratories, Japan, described standard in that they both use E -MAC system and decodes the movement when extra lines are the NHK system intended for time -multiplexed analogue com- signal as a normal 4:3 picture. generated. To get optimum HDTV transmission through the ponents, time compression of Philips Research Laboratories results a suitable algorithm is Japanese DBS satellite. It has these components and digital have also been considering var- needed to calculate the right 1125 scanning lines, 2:1 inter- audio. But, as is well known, ious MAC type methods of coding information to go in these lines, laced, a field frequency of 60Hz C-MAC/packets fits into the nor- for EDTV based on the 625 -line and probably an adaptive tech- and a 5:3 aspect ratio. mal time frame of the existing time frame. These all assume a nique will be needed. In each line, the relevant 625 -line standard for compatibil- horizontal bandwidth of 8.4MHz. Similar work on up -converted luminance and chrominance sig- ity purposes, and video informa- In one method, as described by displays was described by D.W. nals are sent as time multiplexed tion is time multiplexed with 751 - S.L. Tan and R.W. Jackson, the Parker and L.J. van de Polder of components, with R-Y and B-Y bit packets of digital data which luminance and chrominance Philips Research Laboratories. chrominance information on can be used as required for digital information is interleaved verti- Their systems include: 625 -line sequential lines. This means that audio channels or other data. The cally rather than horizontally. sequential displays at 50Hz field these two components have to be 'C' in the name is simply a code Chrominance signals are line frequency using one -line, one- time compressed so that they can letter for the particular method sequential and time compressed field and and two -field stores for be contained within the line chosen for multiplexing the ana- by 4:1. This had the advantage of interpolating the extra informa- period. With the initial video logue video components and the allowing the full 8.4MHz channel tion required; 1249 -line displays bandwidths (e.g. 20MHz lumin- digital audio and data. bandwidth to be used for the with 2:1 interlace; and up-con- ance) this results in a baseband But in another paper, M.D. luminance signal, now uncom- versions with 100Hz field fre- width too large for the normal Windram and R. Morcom of the pressed. quency to overcome large -area DBS channel. So the signals are IBA showed how C -MAC can In another method the B-Y flicker. bandwidth -reduced by sub- become E -MAC - extended chrominance signal is inserted in These researchers say that, if a Nyquist sampling over a 4 -field MAC - to carry higher definition the field blanking interval and the free choice of display standard sequence and thus transmitted in pictures on the gradualist EDTV R-Y signal is time multiplexed were available, they would plump analogue form. Two companded principle discussed above. This horizontally with the luminance for a system with about 800 lines digital audio signals are multi- provides a wide aspect ratio, information. Here, one advan- sequentially scanned at a field plexed in the field blanking extended resolution, and MAC's tage is that the R-Y information rate of about 60Hz. 38 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

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The advanced design of the Neptune 2 makes it the lowest cost real -life A` industrial robot. lt is electro -hydraulically powered, using a revolutionary water based system (no messy hydraulic oilll It performs 7 servo -controlled axis movements (6 on Neptune I ) - more than any other robot under El 0,000. Its program length is limited only by the memory of your computer. Think what that can do for your BASIC programming skills! And It's British designed, British made.

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Automatic triple speed control on Neptune 2 for accurate homing in .. Solve all your Power Problems by contacting Easy access for servicing and viewing of working pans. Powerful - lifts 2.5 kg vhth ease E.M.S. Hand held simulator for processing (requires ADC optionl Neptune robots are sole in kit form as roluws main £95.00 E.M.S. specialise in systems to eliminate your Neptune l robot kit (inc. power supplrl £1250.00 Aix oPtwn (component tit to control board) Neptune I control electrorcCs (ready buutl £295.00 Hydraulic power pack (ready assemb,edl £435.00 Gripper sensor E31. 50 power problems. Neptune l simulator £45.00 Optional extra three firgeredgnpper E75.00 Neptune 2 robot kit hm Power suPPIYI £ 1125.00 BBC connector lead £ 12.50 Products range from 35VA switched square wave Neptune 2 control electron. (ready builtI £115.00 Commodore VIC 20 connector lead and plug-in board £ 14.50 Neptune 2 simulator £52.00 Sinclair Lit Spectrum Conner for lead [15.00 Power Packs to 1KVA fully uninterruptible sine All prices exclusive of VAT and valid until the end of March MI5

wave systems. (a Men[M 15 all -tenon in devon and manufacture and comes In k t fpm at an astonishingly row mentor prrce E.M.S. also manufacture chargers which range up Mentor robot ktlrnc. powerwpPlyl C315.0u desk -top robot Mentor Control electronics to 60 amps. ompct.orically powered training heady bull' £135.00 ,rot has 6 axeszi of movement simultaneously Mentor Simulates Irequda s - [ (fed: It gives smooth operapon. ACC option) £42.00 rnd its rugged construction makes it ideal for ADC oppon ht 1p control in educational establishment. Otner ICanponeno use electronics bronze and nylon BBC connector lead £ 12.50 For further details please contact: aannrsincludeIntegralteg l Cana electronics and special orcuitry for menial Commodore VIC 20 connector lead iampmsatwn. optional on.baard ACC, and and Mogan board £ 11.50 hive Nepld simulator as the teaching pendant Sinclar ZX Spectrum corx,ectw lead £15.00 E.M.S. Manufacturing Limited fee Neptune. Mentors program length is y ny your computer's memory All price xcroslve of VAT and valid until the Chairborough Road rig yi.rrni.T hrh tv sic end or March roes High Wycombe CYBERNETIC APPLICATIONS LIMITED Rya Ic PORTWAY TRADING ESTATE. ANDOVER, HANTS SP O 3PR Bucks pplleatlans TEL (02641 50093 Telex: 477019 Tel: (0494) 448484

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ELECTRONICS & WIRELESS WORLD DECEMBER 1984 .39

www.americanradiohistory.com O1-2081177 TECHNOMATIC LTD 01-208 1177

DISC DRIVES BBC Micro Computer System These drives, fitted with high quality JAPANESE mechanisms are supplied in attractive steel cases painted in BBC colour. The drives are fully Shuggart A4000 compatible. All dual drives BBC Computer & Econet Referral Centre are supplied with integral power supply whilst singles are supplied with or without power supply. All drives come complete with data & power cables, manual and BBC formatting disc. BBC Computers: 1 x100K (250KDD unformatted) 40TSS TS55A TEAC £100 (a) 1 x400K (1 MbDD unformatted) 80TDS TS55F TEAC 40/80 £165 (a) Model B: £320 (a) B+DFS: £400 (a) 2X400K (.5MbDD unformatted) 40TSS TD55A TEAC £280 (a) Model B+NFS: £389 (a) B+NFS+DFS £450 (a) 2X400 (2MbDD unformatted) 80TDS TD55F TEAC 40/80 £420 (a) CS100 TEC with psu £135 (a) 40/80T Switch Module £30 (c) ACORN 2nd Processors: 6502: £175 (a) Z80: £352 (a) CS200 TEC with psu £165(a) 3in. Hitachi 100K 40T £105 (b) TORCH UNICORN: Z80 Card: £299 (a) Z80 Disc Pack: £699 (a) CS400 MITS with psu £195 (a) TD55M Mitsubishi £400 (a) UNICOMM Communications Package: £159 (b) 20 Mbyte Hard Disc+400K Floppy: £1995 (a) We stock the full range of ACORN hardware and firmware and a very wide Authorised Distributor range of other peripherals and firmware for the BBC. For detailed Data Recording Products specifications and pricing please send for our leaflet. 3M 3M FLOPPY DISCS PRINTERS Industry Standard floppy discs with a lifetime guarantee Discs in packs of 10 40 Track SS DD £15 (c) 40 Track DS DD £18 (c) EPSON: RX8OFT £225 (a); FX80 £318 (a) 80 Track SS DD £22 (c) 80 Track DS DD £24 (c) FX100 £435 (a) KAGA TAXAN:KP 810 £249 (a); KP 910 £369 (a) BROTHER: HR15 £350 (a);. DRIVE ACCESSORIES JUKI 6100 £340 (a) FLOPPICLENE Disc Head Cleaning Kit with 28 disposable cleaning discs ensures continued optimum performance of the drives. £14.50(c)

Single Dise Cable £6(d) Dual Disc Cable £8.50(d) ACCESSORIES 10 Disc Library Case £1.95(c( 30 Disc Storage Box £6(c) EPSON Serial Interface: 8143 £28 (b); 8148 with 2K buffer £58 (b). 30/40 Disc Lockable Box £14(c) 100 Disc Lockable Box £19 (b) EPSON Paper Roll Holder £17 (b); FX80 Tractor Attach £37 (b); RX/FX80 Dust Cover £4.50(d) EPSON Ribbons; MX/RX/FX80 £5.00; MX/RX/FX100 £10 (d). JUKI: Serial Interface £60 (a); Tractor Attach, £99 (a); Sheet Feeder £199 (a); Ribbon £2.50 (a) BROTHER HR15: Sheet Feed £199; Ribbons - Carbonor Nylon £4.75; Multistrike £5.50 (d); MONITORS 2000 Sheets Fanfold with extra fine perf. 9.5in.- £13.50;15in. £17.50 (b). MICROVITEC 14in. RGB Parallel Lead Serial Lead (d). BBC £8; £7 1431 Std Res £195 (a); 1431 Ap std Res PAL/Audio £215 (a); 1451 Med Res £295 (a): 1441 Hi Res £399 (a); 203120in. Std Res £360(a); Plinth for 14in. Monitors £8.50. BT Approved Modems Microvitec Monitors with TTL/Linear Inputs also available. MIRACLE WS2000: KAGA VISION Ill The ultimate world standard modem covering all common Hi Res 12in. RGB £345 (a); BELL and CCITT standards up to 1200 Baud. Allows communi- SOFTY II Green Screens; KAGA 12G £106(a); SANYO DM 811 112CX £99(a); cation with virtually any computer system in the workd, The Swivel Stand for Kaga Green £22.50 (b); This low cost intelligent optional AUTO DIAL and AUTO ANSWER boards enhance the BBC Leads: KAGA RGB £5 Microvitec £3.50; Monochrome £3.50 (d) considerable facilities already provided on the modem. Mains eprom programmer can powered. £129 (b) Auto Dial Board/Auto Answer Board £30 (c) program 2716, 2516, each. Software lead £4.50 2532, 2732, and with an TELEMOD 2: adaptor, 2564 and 2764. Complies with CCITT V23 1200/75 Duplex and 1200/1200 half Displays 512 byte page on UV ERASERS PRINTER BUFFER This printer sharer/buffer provides a simple way to Duplex standards that allow communications with VIEWDATA TV - has a serial and par- UV1T Eraser with built-in timer and mains indicator. upgrade a multiple computer system by providing allel I/O routines. Can be Built-in safety interlock to avoid accidental services like PRESTEL, MOCRONET etc as well as user to exposure greater utilisation of available resources. The buffer used as an emulator, cas- to the harmful UV rays. user communications. Mains powered. £37 (b) offers a storage of 64K. Data from three computers It can handle up to 5 eproms at a time with an average BUZZ BOX: sette interface. can be loaded into the buffer which will continue erasing time of about 20 mins. £59 + f2 p&p. V21 Softy II £195.00(b) accepting data until it is full. The buffer will automati- This pocket sized modem complies with 300/300 Baud UV1 as above but without the timer. £47+£2 p&p Adaptor for 2764/ cally switch from one computer to next as soon as and provides and ideal solution for communications between For Industrial Users, we offer UV1408 UV141 erasers that computer has dumped all its data. The computer users, with main frame computers and bulletin boards at a very 2564 £25.00 with handling capacity of 14 eproms. UV141 has a then is available for other uses. LED bargraph indi- economic cost. Battery or mains operated. £52 (c) Mains built in timer. Both offer full built in safety features cates memory usage. Simple push button control Adaptor £8 (d) UV140 £61, UV141 £79, p&p £2.50. provides. REPEAT, PAUSE and RESET functions. BBC to Modem data lead £7 Integral power supply. £241(a).

ATTENTION All prices in this double page advertisment are CONNECTOR SYSTEMS subject to change without notice. ALL PRICES EXCLUDE VAT I.D. CONNECTORS EDGE AM PHENOL RIBBON Please add carriage 50o unless (Speedblock Type) CONNECTORS CABLE No of Meader Recep- Edge CONNECTORS (grey/metre) indicated as follows: ways Plug 'acle Conn. 36-way plug Centronics t0 -way 40p 0.1" o.156.. (a) £8 (b) £2.50 lc) £1.50 Id1 £1.00 Para) lei l Solder £5.25 113C £5.25 16 2019 125p 195p -way 60p 2 ) 6-way (commodore) 300p - Centronics 20-way 85p 26 175p 150p 240p 2.c 10 -way 150p 36-way socket 26-way 120p 34 200p 180p 320p 2 x 12 -way (vie 20) 350p Para) IellSolder £5.50 IOC £5.50 ACORN IEEE INTERFACE - 34 -way 160p 40 220p 190p 340p50 2 x 18 -way 140p 24 -way plug IEEE Solder £5 IDC £4.75 A full implementation of the IEEE -488 standard, pro- - 40 -way 180p 200p 390p 2 x 23-way (Zx81) 175p 220p 24 -way socket IEEE Solder £5 IDC £4.75 50 -way 200p viding computer control of compatible scientific & 2 x 25-way 225p 220p 64 -way 280p technical equipment, at a lower price than other sys- 2 x 28-way (Spectrum) 200p - PC8 Mtg Skt D 2 x 36-way 250p Any Pin 24 way Solder 600p tems. Typical applications are in experimental work MIN CONNECTORS - 1 x 43-way 260p - 36 way ZOC 650p in academic and industrial laboratories. The inter- 9way "Sway 25wxy37 way 50way 2 x 22-way 190p - MALE 2 x 43-way 395p face can support a network of up to 14 other compati- sOltler 809 852 1.25E 1.709 8009 1 x 77 way 400p 500p ble would typically link items of an9lec .209 1.80p 2A0p 3.509 - devices, and several FEMALE 2x50-way(S100connr 600p - DIL test equipment allowing them to run with the opti- solde, 9pp 1.]Op 1.%p x.9pP s.00p are.ró0p 210p 2.90p aAOp - RS 232 JUMPERS mum of efficiency. The IEEE Filing System ROM is rwppimp- HEADERS sideenvyi 902 850 900 1.500 - (25 way DI supplied £282. 25 way Centro. Type conn 5.50 pounds EURO CONNECTORS 24" Single end Male £5.00 Solder I IDC 31 C ty.0 S.SODDunda 24" Single end Female £5.25 VC 25 xay pluq 345p5ucxe1 1.50> DIN 41612 14 24" Female Female £10.00 pin 40p 100p 2 x 32 way St Pin 230p 275p PROGRAMMER 24" Male Male £9.50 16 pin 50p 110p INDUSTRIAL 2 x 32 way Ang Pin 275p 320p 24" Male Female £9.50 24 pin 150p EP8000. TEXTOOL ZIF 3 x 32 way St Pin 260p 300p 28 pin 200p - This CPU controlled Emulator Programmer is a pow- SOCKETS 24 -pin £5.75 3 x 32 way Ang Pin 375p 400p 40 pin 200p 225p erful tool for both Eprom programming and develop- 28 -pin £9.00 40 -pro £9.75 IDCSktA+B 275p ment work. EP8000 can emulate and program all IDC Skt A + C 350p TEST CLIPS eproms up to 8Kx8 bytes, can be used as stand For 2 x 32 way please specify 14 -pin 375p 16 -pin 400p DIL SWITCHES 40 -Din £10.30 alone unit for editing and duplicating EPROMS, as a 4 -way 90p 6 -way 105p spacing (A + B, A + C). slave programmer or as an eprom emulator £695(a) 8-wav 120E 10 -way 150E

40 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com 74 SERIES 74273 2.00 74LS261 1.20 740571 3.00 4094 0.90 74276 1.40 7415266 0.80 745573 5.00 4095 0.90 LINEAR ICs COMPUTER COMPONENTS 7400 0.30 74278 1.70 7415273 1.25 4096 0.90 Cvu EPROM, KEYBOARD 4097 2.70 AD7581 15.00 171711 1.00 T47310 7 1.50 8287 P.O.A. MC14412 7.50 7401 0.30 74279 0.90 7418279 0.70 74C SERIES ADC0908 11.80 174723 0.80 184841847 4.00 ENCODE Rs 4098 0.75 1802 E 6.50 8288D 11.00 75107 0.90 7402 0.30 74283 1.05 7413280 1.90 4099 601791000 3100 L12724504 300 T9922 1.20 0.90 2650A 12.00 8755A 24.00 2516+5V 3.50 75108 0.90 7403 0.30 74285 3.20 7410283 0.85 74000 0.70 4501 0.38 ÁN103 2.00 13.4733 0.40 789800 0.90 AY52376 11.50 94-35050 1 40 114741 00 T89010 0.80 6502 3.50 TMS9903 25.00 2516-35 5.50 75109 1.20 7404 0.38 74290 0.90 7410290 0.85 74004 0.50/ 4502 0.55 ÁY53600 7.50 503 0.35 AY -11270 1.50 174747 0.70 784820 0.60 55002 15.00 TMS9911 18.00 2532 4.50 75110 0.90 7405 0.30 74293 0.90 7418292 9.00 4069 AY -3-1350 0.75 74C922 6.50 4504 0.95 3.50 1139620M 85028 5.50 TMS9914 14.00 2532-30 5.50 75112 1.60 7406 74298 1.90 7415293 74008 0.70 44-14910 4.00 LM1011 4.80 708920 200 74C923 6.50 0.40 0.90 4505 3.60 650213 8.00 A4-14912 1.50 T99950 2.25 Z80P10 2.60 2564 6.50 75113 1.20 7407 0.40 74351 2.00 7418295 1.40 74010 0.70 4506 0.90 5.00 L741014 BAUD RATE CA3019A 1.00 181801 3.00 TC9109 5.00 6800 2.50 Z88AP10 3.25 2708 3.00 75114 1.40 7408 0.30 743858 0.80 741_0297 9.00 74014 0.50/ 4507 0.35 GENERATORS 4508 1.20 030284 1.10 L01630 2.50 50A210 3.50 5802 2.60 Z8OCTC 2.60 2716+15V 3.50 75115 1.40 7409 0.30 74366A 0.80 741_5298 1.00 40106 4584 CA3046 0.70 1147871 3.00 TCA220 3.50 4510 0.55 5809 6.50 Z80ACTC 3.25 2716-35 5.50 75121 1.40 M014411 750 7409 0.30 74367A 0.80 7410299 2.50 74C20 0.70 CA3059 3/5 1741872 300 TCA270 3.50 4511 0.55 6809E 12.00 Z80DART 6.50 2732 4.50 75122 1.40 COM81I6 7410 0.30 74368A 0.70 7415321 3.70 74032 1.00 4512 0.55 CA3060 3.50 101686 8.00 TCA940 1.15 6.50 CA3080E 070 11411889 4.50 1120100444 5.00 68809 12.00 Z80ADART8.00 2732A-2 7.00 75150P 1.20 47028 7.50 7411 0.30 74376 1.60 7415322A 3.90 74042 1.50 4513 1.40 4514 1.10 CA3086 0.40 102917 3.00 7081010 2.25 684309E 16.00 Z800MA 8.00 27324-30 6.00 75154 1.20 7412 0.30 74390 1.10 7415323 3.30 74048 1.50 03085E 2.10 103302 0.75 11341022 1.60 UA RT 4515 1.10 68000-L8 36.00 7MS450014.00 27324-35 5.50 75159 2.20 7413 0.50 74393 1.20 7410324 3.50 74073 1.00 4516 CA309070 3.75 LM3900 0.80 TDA1024 1.10 0.55 8035 5.00 TMS9901 5.00 2764-25 5.00 75160 5.00 4131015P 7414 0.70 74490 1.40 7410348 2.00 74074 1.20 4517 2.20 CA3130E 0.90 L03909 1.00 TDA1170S 3.00 3.00 CA31301 1.30 1/.13911 1.80 T0A2002 1.05 8039 5.00 TMS9902 5.00 27256-30 54.00 75161 3.50 AY51013P 7416 0.36 7415352 1,20 74076 1.00 4518 0.41 3.00 4579 0.32 CA3140E 0.45 103914 3.50 T0Á2003 1.00 8080A 4.20 Z8OADMA 9.00 27256-25 80.00 75162 4.00 COM8017 3.00 7417 0.40 7419 SERIES 7410353 1.20 74C83 2.00 CA31401 1.40 103915 340 7092004 3.40 ; 520 0.80 8085A 6.50 Z8OASIO 9.00 27C64-25 14.00 75172 3.00 IM6402 3.60 7420 0.30 7410356 2.10 74085 2.25 521 1.15 03146 225 1163976 3.40 1092008 320 8086 22.00 27128-2518.00 75182 0.90 TRI602 3.00 7421 0.60 741500 038 7410363 1.80 74C860.50/40/ 4522 0.40 03160E 0.90 1013800 150 704142120 320 MEMORIES 03161E 160 0515131 2.30 1DA2030 1.00 8088 17.50 27128-3016.00 75188 0.60 7422 0.36 741001 0.28 7418364 1.80 70 4507 4526 0.70 MODULATORS 527 0.80 03162E 4.40 0515161 4.50 1DA2541 4.00 8748 P.O.A. TMS2716 5.00 75189 0.60 7423 0.36 741502 0.28 7415365 0.52 74090 1.90 03789E 2.70 003712 2.00 TDA2591 4.00 2016-150 6.00 528 0.40 TMS1601 12.00 75365 1.50 6MHZ 3.75 7425 0.40 741503 0.28 7415366 0.52 74C93 1.50 4529 1.00 CA3240E 1.50 003730 4,00 1042593 5.00 2101 4.00 TMS9980 12.00 CRT 75450 0.80 BMHZ 4.50 7426 0.40 74L804 0.28 7415367 0.52 74095 1.60 4631 0.75 CA3280G 2.70 MC131017 1.50 1092653 7.00 2102 2.50 0D7002 12.10 MC1413 010 1093560 9.50 TMS9995 12.00 75451 0.50 7427 0.32 741805 0.28 7410368 0.50 740107 1.00 4532 0.40 2107B 5.00 CONTROLLER DAC1460.8 2.25 MC1445 2.50 7043010 1.50 WD55 14.50 SOUND 8 VISION 741508 74C150 5.00 4534 3.80 2111A-35 4.00 75452 0.50 7428 0.43 0.28 7415373 1.00 4536 D4C0800 2.25 4411456 0.45 1047000 9.50 CRT5027 18.00 2.50 Z80 2.80 75453 0.70 12MHZ 12.00 7430 0.30 741S09 0.28 7410374 1.10 740151 2.00 4538 DAC0808 2.25 0014951. 2.50 TE91002 700 2114-21 3.50 CRT6545 0.75 Z80A 3,75 9.00 75454 0.70 7432 0.36 741510 0.28 7410375 0.75 740157 2.50 4539 0.75 06308 3.00 MC1496 0.70 TLO81CP 0.40 2114-31 2.50 EF9364 8.00 CRYSTALS N41366 1.90 MC33400 200 11082 090 7806 8.00 75480 1.50 7433 0.30 74L811 0.28 7415377 1.40 74C160 1.80 4541 0.90 2114-4L 2.00 EF9365 30.00 4543 0.70 017106 4.75 7003401 0.50 71084 0.00 75491 0.65 32.768KHz11.00 7437 741012 0.28 7418378 1.10 740161 1.90 SUPPORT 2147 3.20 0.30 4551 1.00 017671 0.95 MC3403 0.65 71071 0.40 EF9366 30.00 74L813 740162 DEVICES 4027-3 75492 0.65 1.00MHz 2.70 7438 0.40 0.34 7415379 1.40 1.80 4553 2.40 10116500 400 MFIOCN 3.40 11072 0.10 3.00 EF9367 36.00 11074 1.10 8126 1.20 1.8432MHz2.25 7439 0.40 741014 0.52 7418381 4.50 74C163 1.80 4555 0.36 017660 2.50 0050240 9.00 2651 12.00 4116-15 2.00 11061 MC6845 6.50 1.20 2.00MHz 2.25 741015 0.28 7415390 0.80 740173 1.00/ 4556 0.50 ICL6038 3.00 74050398 7.90 0.35 4116-20 1.75 8728 7440 0.40 I04172160 22.00 01920 5.00 11062 0.55 3242 8.00 1.1C88455P 7.50 741.020 0.28 7415393 4076 4557 2.40 4118-3 5.00 8T95 1.20 2.45760MHz(L) 7441 0.90 1.10 4560 £1.47217 7.50 ..922 4.00 T1083 0.75 3245 4.50 MC6847 6.50 1.40 4164-15 8196 1.20 2.00 7442A 0.70 74L821 0.28 74103956 1.30 740174 1.50 4566 1.40 I0M7555 1.00 646221A 3.00 11084 1.00 6520 3.00 5.50(11( SFF96364 8.00 NE529 2.20 BT97 1.20 2.45760145z(S) 7443A 1.00 741.022 0.28 74LS399 1.40 74C175 1.50 4568 2.40 1C1.17556 740 TL094 2.00 6522 3.50 4164-15 5.00 TMS9918 LC7120 3.00 NE531 1.20 1L0170 0.90 30.00 8198 1-20 250 7444 1.10 741524 0.50 7418445 1.80 74C192 1.50 4589 170 4164-20 4.50 LC7130 300 NE544 1.40 1L430C 1.30 6522A 5.50 TMS9927 14.00 741826 4572 0.45 4416-15 811_$95 1.40 2.5MHz 2.50 7445 1.00 0.28 741_5465 1.40 74C193 1.50 LC7131 3.50 NE555 0.22 U4410013 3.35 6532 5.20 5.00 TMS9928 20.00 4583 0.90 4532-20 811096 2.20 2.662MHz 12.50 7446A 1.00 74LS27 0.28 7415467 1.80 74C194 1.50 4384 0.44 LC7137 3.50 NE556 0.80 04.759 3.20 6551A 1.50 2.50 TMS9929 16.00 811.097 1.40 3;121MHz I 1.75 7447A 1.00 741028 0.28 741.8490 1.50 74C195 1.50 4585 0.60 LF347 1.50 NE564 4.00 U42240 1.30 6821 2.20 4816AP-3 2.00 LF351 0.80 NE565 1.20 U44170 1.70 811098 220 3.276MHz 1.50 7448 1.00 741530 0.28 741.5540 1.40 740221 2.50 4724 1.50 6829 12.50 5101/5501 3.70 INTERFACE 1440 750 1E353 0.90 NE566 1.50 UCN40014 8.50 5.00 3.5795MHz1.00 7450 741_032 0.28 741_5541 1.40 740244 2.00 5516 6.50 108 881.5120 0.36 14412 7.40 1E355 0.00 NE567 1.25 0114200147 0.60 6840 3.75 6116P-3 5.00 9602 3.00 4330MHz 1.50 7451 0.35 741533 0.28 7418608 7.00 740245 2.25 14416 3.00 1735614 0.95 NE570 4.00 O1.142002A 0.60 68840 6.00 AD561J 20.00 9636A 1.60 4.194MHz 2.00 7453 0.38 741537 0.28 7410610 19.00 74C373 2.25 14419 210 17357 1.00 NE571 3.00 3192003A 0.90 6850 1.60 6116LP-3 5.50 LF13331 3.50 NE592 0.90 013420049 0.90 AM25510 3.50 9637AP 1.80 4.4304Hz 1.00 7454 0.38 74L838 0.28 7410612 19.00 74C374 2.25 1ú90 4.20 68650 2.50 6264-15 28.00 95 4.50 LMIOCLH 4.50 NE5532P 1.50 U1142068 2.90 AM25LS25213.50 9638 1.60 4.608MHz 2.50 7460 0.55 741040 0.28 7115624 3.50 740902 1.20 6514-45 2.50 14509 6.50 103019 0.30 NE5533P 1.60 U1342602 1.40 6852 2.50 AM25152538 3.50 741542 0.55 740911 9.00 68/0 1.60 4.9152MHz2.50 7470 0.50 7415826 2.25 14599 2.00 10307 0.45 NE5534P 1.20 4192803 1.90 6854 6.50 AM26LS31 103060141 0.75 NE5534AP 1.50 0152804 1.30 1.20 DISC 5.00MHz 1.50 7472 0.45 741043 1.50 7418628 2.25 710912 4.50 22100 3.50 681354 8.00 748189 2.25 LM310 2.25 0707E17 5.00 11RC575 2.15 AM2610321.20 COI. TR E P 6.00MHz 1.40 7473 0.45 741047 0.90 7410629 1.40 740922 6.00 22101 7.00 6875 5.00 745201 3.50 22102 7.00 1.14371 040 011024 5.00 UPC59271 2.00 AM79100C 31.00 ICs 8.144MHz 1.40 7474 0.50 741548 0.90 7415640 3.00 740923 6.50 111316 1.50 RC4136 UPC1156M 3.00 8154 745289 2-25 40014 0.40 0.55 8.50 DAC80- 7.00MHz 1.50 7475 0.60 741551 0.30 7418640-13.00 74C925 8.50 10319 1.60 RC4751 2.40 OP6115511 3.50 8155 93415 6.00 40085 1.20 5.00 C81 -V 28.00 6843 8.00 7.168MHI 1.75 7476 0.45 741554 0.30 7418641 2.00 740926 7,50 40097 0.36 1171324 0.45 RG195 1.50 X0210 4.00 8156 4.00 934.422 9.50 1.643342 1.15 804.558 0.55 X02209 300 DM8131 6.00 8272 26.00 1.50 7480 741055 0.30 7415642 2.50 40098 0.40 93425 8.00MHz 0.65 120 10112207 8205 2.25 6-00 FD1771 74ALS SERIES 40100 1.40 LI43352 S566B 2.20 3.15 DP8304 3.50 20.00 8.867MHz 1.75 7481 1.80 74L5738 0.30 7418642-13.00 114336 140 550240 9.40 X112211 5.15 8212 2.50 40707 1.25 PROMS DS3691 5.00 F01791 20.00 10.00MHz 1.75 7483A 1.05 741574A 0.38 7410643 2.50 40102 174339 0.40 S441900 16.00 X02216 8.15 8216 1.50 1.60 0S8830 1.40 FD1793 20.00 10.50MHz 2.50 7484A 1.25 741075 0.48 7415643-13.00 74ALSOO 0.45 40103 2.00 11.4148 0.80 5AD10249 11.50 0112240 120 8224 3.00 1143587 0.50 SFF983G 8.00 29404 1.00 28122 4.75 DS8831 1.50 FD1795 28.00 10.70MHz 1.50 7485 1.10 7410768 0.43 741_0644 3.50 7461_802 0.45 40104 1.20 8226 3.00 40105 150 L0377 2.10 5/490 3.40 214414 0.60 24010 2.50 DS8832 1.50 FD1797 2200 11.00MHz 3.00 7486 0.42 74LS78 0.42 7415645 2.00 7481SO4 0.50 40106 0.48 1.1.4380N-0 1.50 571740139 3.00 ZN419P 1.15 8228 2.70 180030 2.00 058833 2.25 WD2793 36.00 12.00MHz 1.50 7489 2.10 74LS83A 0.70 741045-1 4.00 7461_008 0.50 40107 L0340N 1.20 S7476023N 300 ZN423E 1.30 8243 4.50 0.55 1858030 2.00 058836 1.50 WD2797 32.00 14.00MHz 1.75 74906 0.55 741585 0.80 7415668 0.90 7481510 0.45 40108 3.20 L14381471 1.70 9N700335 3.00 ZN-1246 1.30 8250 9.50 1.1.1382 2.00 54476115N 2.15 ZN425E8 3.50 74S188 1.80 058838 2.25 W01691 15.00 14.318MHz11.60 7491 0.70 741086 0.35 7410669 0.90 7481S20 0.45 40109 0.80 8251A 5.00 40110 2.25 LM3&1 3.25 5N78477 6.00 214420E8 3.00 745287 2.25 LF13201 4.50 W02143 8.00 14.756MHz2.50 7492A 0.70 741590 0.54 7415670 1.80 7481032 0.45 40114 225 13.13841 2.20 9476489 4.00 214427E8 4.00 82530-5 8.00 745288 1.80 MC1488 0.60 15.00MHz 2.00 7493A 0.55 741091 0.90 7410682 3.20 7461_074 0.70 11.138871.1 1.00 S076495 4.00 Z7029E8 4.50 40117 2.40 8255ÁC-5 5.50 745387 2.25 MC1489 0.60 I6.00MHz 2.00 7494 1.10 741592 0.60 7415684 6.50 7461.5138 1.50 40163 1.00 LM387 2.70 S1476660 1.20 25429E8 2.25 8256 24.00 11.4389 1.80 5110256432 7.00 214447E 0.40 748473 4.75 MC3446 2.50 C"+RAC TER 17 734MHz200 7495A 0.60 741093 0.54 7415687 5.50 7481S139 1.50 40173 1.20 82570-5 4.00 40174 1.40 10391 1.80 509515 7.50 214459E 1.00 745474 4.00 MC3459 4.50 GENERATORS 18.00141-12 1.70 7496 0.80 74LS958 0.75 74815244 4.00 1.10 4005 1.00 (.643925 T47120 1.20 Z14455CP 2.00 82590-5 6.50 745570 6.50 MC3470 4.75 18.432MHz 1.50 741_096 0.90 745 SERIES L74393 0.85 747130 1.40 257034E 2.00 7497 2.10 7481S245 4.75 40792 1.00 8275 29.00 740571 903251311C 7.50 LM394CH 1.50 21491040 3.00 MC3480 8.50 19.969MHz1.50 74100 1.90 7415107 0.43 7481S573 260 40193 100 3.75 107204 3.40 114709 0.35 107205 0.90 ZN9134J 23.50 8279 6.50 745571 3.00 MC3486 2.25 R0325131C 7.00 20.000MHz1.75 74107 0.50 7415109 0.43 74500 0.50 74610574 4.50 40194 1.00 8284 7.50 40244 1.50 10710 0.48 191062 160 2144234E 6.50 745573 5.00 M03487 2.25 DM865641200 24.000MHz1.50 74109 0.75 7415112 0.45 74502 0.50 74618580 280 40245 1.50 8282 4.50 82523 1.50 MC4024 3.25 MCM66760 7.50 48.000MHz1.75 74110 0.75 7415113 0.45 74504 0.50 VOLTAGE 40257 1.80 REAL TIME 8283 4.50 825123 1.50 MC4044 3.25 5N745262AN 116MHz 2.50 74111 0.55 7415114 0.45 74505 0.50 40373 1.40 4000 SERIES REGULATORS CLOCK 82S129 1.75 MC14411 9.00 1o00 PX01000 1200 74116 1.70 7410122 0.70 74508 0.50 40374 1.40 80095 0.75 MC6818P 4.50 74118 1.10 7418123 0.90 74510 0.50 IA FIXED VOLTAGE PLASTIC 70221 7418124 4000 0.20 80097 0.75 M7415817AN 8.500 74119 1.70 1.40 74511 0.75 80C96 0.75 +vE -vE LOW PROFILE SOCKETS BY TI WIRE WRAP SOCKETS BY TI 4001 0.24 9SM5832RS 3.50 74120 1.00 7415125 0.50 74520 0.50 4002 0.25 5V 7805 085 7905 0.50 007806 0.50 7908 050 74121 0.55 7410126 0.50 74522 1.00 4006 0.70 TELETEXT 8 pin 9p 18 pin 16p 24 pin 24p 8 pin 30p 18 pin 50p 24 pin 75p 4007 DISPLAYS 64 7808 0.50 7906 050 74122 0.70 7410132 0.65 74530 0.50 0.25 DECODER 14 pin 10p 20 pin 18p 29 pin 26p 14 pin 42p 20 pin 889 28 pin 100p 4008 0.40 129 7812 0.45 7912 030 74123 7410133 0.50 74532 0.60 154 7815 0.50 16 pin 11p 22 22p 40 pin 30p 16 pin 45p 22 pin 75p 40 pin 1309 0.80 4009 0.45 0.60 7915 SAA5020 600 pin 74125 0.65 741.8136 0.45 74537 0.60 4010 0.40 01.7040ED 1.40 18V 7818 0.50 7918 0.50 7824 7924 8865030 7.00 74126 7410138 0.60 74538 0.75 4011 0.14 DL707RED 1.40 244 0.50 0.50 0.55 SAA5041 16.00 8 pin 14 71n 16 pin 18 pin 20 pin 24 pi 28 pin 10 pin 4012 0.25 IA FIXED VOLTAGE PLASTIC T092 TURNED PIN 74128 0.55 7410139 0.60 74540 0.50 FND357 1.00 259 320 36p 100 4013 4.38 SAA5050 9.00 LOW PROFILE SOTS. Bhp 600 759 1600 74132 0.75 7415145 1.10 74S51 0.45 FND500/ 4014 0.40 5V 78105 0.30 SV 79105 0.45 741_5147 1.75 74136 0.70 74564 0.45 4015 0.70 TIL730 1.00 6V 78106 0.30 124 79112 0.50 84 78108 0.30 15V 79115 TIP29A 35p 74141 0.90 7410148 1.40 74S74 0.75 4018 0.36 FND507/ 0.50 TRANSISTORS 251613 38p 296059 325p 1A 4006 250 129 78112 0.30 TIP29C 400 74142 2.50 7410151 0.70 74085 4.50 4017 C.55 711729 1.00 251711 36p 296107 850 IA600V 300 4018 0.40 15V 78115 0.30 11P304 74143 7410152 2.00 74586 1.00 MAN74/ 40161 2 45p B1029 450 350 252102 700 2716247 1900 28 2.70 4019 0.40 50V 306 90107 8 18p BFX30 45p TIP30C OOp 2 N2160 74144 2.70 741_0153 0.70 74S112 1.50 4020 0.40 21764 1.00 350p 296254 130p 28 100V 35p OTHER 6C1 01984,5 30p TIP31A 4017 74145 1.10 7410154 2.00 745113 1.20 4021 0.40 MAN711 09C 20p 2742219Á 300 2140290 65p 244009 45p REGULATORS BC 169C 731686 7 30p TIP31C 45p 74147 1.70 741_0155 0.70 745114 1.20 4022 0.70 DL707 1.00 18p 2522224 30p 2 SCI 306 1000 3A200V 80p 4023 0.30 BC, 72 18p 80088 30p TIP32A 45p 74148 1.40 7418156 0.70 745124 5.50 MAN3640 1.75 Fixed 64911181458 2523694 30p 2SC1307 150p 34 800V 72p 4024 0.40 BC177 300 BF 589 180p 1173 2C 40P 282484 30p 25C1957 74150 1.75 7415157 0.80 745132 1.00 MAN4640 2.00 1003090 745V 140 900 LA 11373V 050 4025 0.24 LM3238 3A 5V 3.50 BC, 78 30p 01, 39p TIP33A 7047 2N2646 SOP 2SCIS39 1507 74151A 0.70 7410158 0.70 748133 0.80 4018 0. MAN6610 2.00 44400V 1000 7800500 545V 5.40 BC182 3 15p 5FY51 2 TIP33C 80p 2042504/5 30p 2SC2028 74153 7418160A 0.75 745138 1.80 4027 040 9585881 5.70 30p 80p 6A 50V 000 0.80 78912 5412V 6.40 BC184 16p TIP34A 9013 74LS181A 075 745139 4029 0.40 5V BEr56 33p 2929068 300 2502029 200p 60 100V 10013 74154 1.40 1.00 TIL311 6.50 78P05 104 9.00 TIP34C 120p 4029 0.75 VARIABLE REGULATORS BC187 30p 131790 90p 292907 30p 2502078 lbOp 64400V 130p 74155 0-80 74101628 075 748140 1.00 4030 0.35 TIL729 1.00 L04305071 2.50 00212 3 1Bp 09739 45p TIP354 120p 292926 120 25C2335 200p 10A400V 7415163A 0.75 740151 1.50 4031 1.25 711730 200p 74156 0.90 1.00 1113177 10-220 1.50 BC214 187 8541920 30p TIP35C 1407 293053 380 25C2612 2000 254400V 4000 74757 0.80 7415164 0.75 745153 1.50 4032 100 MAN8910 2.50 11.43170 703 2.40 4033 1.25 80237 l8p 80104 225p 1I0360 140p 2 N3054 60p 39128 200p 74159 1.75 741S165Á 1.10 745157 2.19 MAN8940 2.50 LM337T 2.25 0IÁ(5 4034 2.40 BC32- 16p 00705 1906 111436C 150p 253055 550 314140 2000 74101666 1.50 745158 2.00 LA43503 104.+VAR 4.00 74160 1.10 4035 0.70 00337 lbp BU108 2500 11P41 SOP 39141 200p 7415168 1.30 745163 103060 10474 -VAR 15.00 253442 140P 74161 0.80 4.00 4036 2.50 DISPLAY 9C338 1710 130109 225p 3410 55p 39201 200p 4037 1.10 253553 2400 304004 800 74162 1.10 7415169 1.30 745169 7.00 DRIVERS 8ROSKC 0540 BC46' 40P 126 4038 1.00 BU 150p 10342 60p 293584 2500 3N204 200p 644004 700 74163 1.10 7415170 1.60 745174 3.00 789000 5A -1-VAR 5.75 4039 2.50 BC477 8 36p BU78071 120p TIP42C 85p 293643-4 48p 40290 2500 705600 1A -1-VAR 2.25 66500V 880 74164 74LS173A 1.10 74S175 3.20 16 7 1.20 4040 0.40 9368 4.50 79HGKC SA-BAR 8.75 13C5 50P BU205 200p TIP54 1500 253702 3 180 40361r2 750 1.10 7415/74 0.75 745188 1.80 4041 0.55 84400V 75p 74185 9370 4.50 790000 to-VAR 2.50 BC54:B 200 BU208 200P TIP55 180P 253704 5 180 40595 120p 7415175 0.75 745189 2.25 4042 0.50 110 80500V 95p 74166 1.40 LM3914 3.50 SWITCHING REGULATORS BC548C B0406 145p 177120 75p 253706,7 18p 40673 100 4043 0.80 017660 2.50 124400V 850 74167 4.00 7413181 2.00 745194 3.00 1313915 3.50 BCS49C l6P 136780 600p TIP,21 750 4087 1,2 4344 0.80 3.00 253706 18p 1O00 12Á500V 105p 74170 7410183 1.90 745195 3.00 503524 BC557 B ISP 2.00 4045 1.00 LM3916 3.50 11494 300 BUY69C 350p TIP122 80o 253773 200p 160.400V 220p 74172 4.20 7410190 0.90 745196 3.50 4046 0.40 0096118 3.20 11097 3.00 BC559C 2417 E310 5064 117125 75p 2143819 40p DIODES 4047 164500V 1307 74173 1.40 7418191 0.90 740204 4.50 0.40 U056184 3.20 78540 2.50 BCY70 30p 532413 2500 T1P126 80p 2N3823 30p 4048 0.55 128000 1300 74174 1.10 7413192 0.90 745201 3.20 004195 50 BCV71 36p MJ802 400p T1P142 1200 BY127 12p 4049 U1.02003 0.90 2843866 90p TIC2060 7415193 0.90 74S225 0.34 00137 750 07036300 200 600 74175 1.05 5.20 4050 0.35 41.012804 0.90 5122501 225p TIPI, 120p 253902 700p 1102260 OPTO -ISOLATORS 130132 80p 0047 10p 757 74176 1.00 74101946 0.75 745240 4.00 4051 0.65 ULN2068 2.90 M37955 90E 11P2955 90P 2N3904 18p TIC2460 1107 4052 0.00 130135 40p 0490/91 90 74178 1.50 741_S195A 0.75 740241 4.00 I/1.92802 1.90 11.074 1.30 TIL111 0.70 MJ300, 22511 11P3055 70p 253906 18p 4053 0.40 BD739 400 MJ4502 4000 11593 0495 9p 74179 1.50 7410196 0.90 745244 5.00 ULN2803 1.80 11074 2.20 TIL112 0.70 30p 254036 850 11-1YR15 TORS 4054 0.40 B0140 40p MJE340 600 VNIOKM 04200 9P 74180 1.00 7410197 0.90 745251 2.50 4055 0.40 11192804 1.90 MCT26 1.00 1IL113 0.70 50p 2144037 BSp 7410221 B D189 600 MJE2955 1500 V5664E 90p 4 04202 10p 74181 3.40 1.00 745257 2.50 4056 0.45 75491 0.70 MC52400 1.90 T11116 0.70 21,4123 27p 3Á400V 45p BD232. 60P MJE3055 120p 05884E El 174914 417 74182 1.40 7415240 0.90 745258 2.50 4059 4.00 75492 0.70 M0C3020 1.50 6N137 3.60 254125,6 270 84600V 180E 4060 010 80233 750 19916 70 74184 1.90 7415241 0.90 748260 1.00 1.75 M7F102 40p ZTX108 160 2N4401 3 250 4U63 0.85 611139 194148 124400V 1500 741_0242 80235 85p MPF1034 40p ZTX300 18p 2144427 90p 40 74185A 1.80 0.90 740261 3.00 4066 0.40 16Á100V 180p OTHERS BD241 SOp MPF 135 40p 45P 154001/2 SP 74190 1.30 7418243 0.90 745262 11.00 4067 2.30 LEDS ZTk452 2144871 500 168400V 1800 130242 6017 MPSA06 30p 27 500 20p 27p 194003/4 8p 74191 1.30 741.0244 0.90 745283 2.70 4066 0.25 2015777 0.50 2165087 01061) 45o 4069 0.24 0.125" 130379 60p MPSA12 50p 776502 20p 154005 0p 74192 1.10 7410245 1.60 745287 2.25 BPX25 1.80 0.2" 2N5089 27p MCR101 36p 4070 0.24 00380 SOp 194006/7 7p 741_0247 1.10 9E0111209 0.12 11L220 0.15 MPSA13 500 IT X504 22p 255172 27p 74193 1.15 740288 2.00 4071 0.24 BPW21 2.80 155401/2 253525 1307 GRN 111211 0.18 711.222 0.18 80677 40p MPS420 500 Z7 X552 55p 255191 90p 120 74194 1.10 7415248 1.10 745289 2.25 4072 0.24 OCP71 1.80 155403/4 254444 1800 VEL 7712120.20 T1L226 0.22 BF2440 40p MPSA42 507 719652 600 255245 40p 14p 74195 0.90 7415249 1.10 745299 5.50 4073 0.24 013712 1.20 155404/5 14p 295060 300 0.24 Real LEDs 012569 500 MPS443 500 ZTX752 700 295401 800 74196 1.30 7410251 0.75 745373 4.00 4075 ORP60 1.20 295061 32p 4078 61257 8 40P MPSA56 30p 25697 35p 1N5404/7 19p 7410253 0.40 (910/91 0.30 2N5459 30p 2145064 35p 74197 1.10 0.75 740374 4.00 4077 0.25 ORP61 1.20 COUNTERS 81337 38o 8935470 18920 9p COO 931 Colour) 500 25698 45p 2145460 000 74198 2.20 7415258 0.90 745387 2.25 4078 0.25 1.00 SFH205 BFR39 320 MPSA93 407 257064 380 2N5485 380 LE ',FRS 741024576 4081 024 1.00 740925 BRIDGE 74199 2.20 745472 4.75 11132 0.55 850 BFR40 I 32p MPSU06 4082 0.25 10 LEO 63p 25708 360 2N5875 250p 74221 1.10 0.70 745473 4.75 11178 74C926 6.50 RECTIFIERS 4065 0.55 BF 679 32p MPSUD7 sop 25918 450 2145883 3750 0.40 (38/Graph. 74C928 6.50 27633V 74251 1.00 741_5258A 0.70 745474 4.00 4086 0.75 TIL 318 1.20 O 1980 I 320 MPSU45 900 '5930 30p 1A 509 190 Red 2.25 2146027 300 40040W 90 74259 1.50 741.8259 1.25 740475 4.50 4089 1.20 11181 1.20 72168 22.00 BFR96 1000 MP6U65 78P :N1131:2 50p A 700V Grn 256052 3000 20p 09 15V 74265 0.80 741.5260 0.75 748570 6.50 4093 5.35 111100 0.75 2.25 ZN1040 6.70

PLEASE ADD 50p p&p & 1507o VAT TECHNOMAI'IC LTD (Export: no VAT, p&p 0t Cost) HAIL ORDERS TO: 17 BURNLEY ROAD, LONDON NW10 1ED Orders from Government Depts. & Colleges etc. welcome SHOPS AT: 17 BURNLEY ROAD. LONDON NW10 11= Detailed Price List on request VISA

ICI ill D`s I ' 4 0000~) rlcv_ l Stock items are normallp by return of post 305 EDGWARE ROAD. LONDON W2 CIRCLE 43 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD DECEMBER 1984 41

www.americanradiohistory.com FIBRE -OPTICS EDUCATOR A New Concept in Optical Equipment

Examples of Applications: The Fibre -Optics Educator is a low-cost, versatile instrument TEST EQUIPMENT designed primarily for organisations involved in or about to Accurate fibre attenuation measurements to 50dB; optical level measurements; enter the field of fibre -optics. testing out analogue and digital optical transmitters and receivers; giving an au- It can function as test equipment and transmission equip- dible indication of low level visible and infra -red radiation using the analogue ment, and is also ideal for training personnel in the growing loudspeaker output or the digital buzzer output, with a length of optical cable act- ing as a probe; measuring rotational or vibrational frequency using light reflec- field of fibre -optics. tion or transmission. The Fibre -Optics Educator comprises fully portable optical transmitter and receiver units, optical cables, together with TRANSMISSION EQUIPMENT free and optical fibres, numerous accessories, a comprehensive manual, and carry- Both digital and analogue transmission over -space using a variety of electrical interfaces. ing case. Included in the features of the transmitter and receiver units are: TRAINING All the fundamental concepts of optical communications can be shown in a con- fre- TRANSMITTER: infra -red I.e.d., red I.e.d., variable output control; variable structive and convincing way. Ideal for training engineers, technicians and TTL, RS232 quency pseudo -random and square wave generators; CMOS and executives. Suitable for industry, colleges and technology training centres. voltage levels and manual digital inputs; high and low impedance analogue in- puts, variable analogue gain. Designed and Manufactured in the U.K. RECEIVER: loudspeaker analogue output, and high and low impedance For further details contact: analogue outputs, variable analogue gain; buzzer digital output, and TTL, ELLMAX Electronics Ltd., voltage levels outputs, variable digital sensitivity. CMOS, and RS232 digital Unit 29, Leyton Business Centre, ELLMAX Power for each unit is from an internal battery, or single external dc power supply aloe Road, Leyton, London, E10 7BT. ELECLTRONICS (9V to 15V). A mains adaptor socket is also provided. Tel: (01) 539 0136 CIRCLE 18 FOR FURTHER DETAILS.

FUNCTION GENERATOR 0.1Hz-500kHz * Sine, Square, Triangle, TTL * Accuracy typically 1% of output range Typically 0.02Hz - 700kHz * Variable DC offset * 7 switched ranges with * External A.M. facility coarse and fine frequency * External sweep facility controls * Short circuit protection * ± 30V output capability all outputs JUPITER 500 (inc. P & P and VAT) £128.80 Co/our leaflet with specifications and prices available from: Designed and BLACK STAR LTD, (Dept.WW) 4 Stephenson Road, St. Ives, -eire manufactured in Britain Black*Star Huntingdon, Cambs. PE17 4WJ, England. Tel: (0480) 62440 Telex: 32339 CIRCLE 9 FOR FUR'T'HER DE'T'AILS.

VIDEO TERMINAL BOARD METER PROBLEMS?

80 characters X 24 lines* 70 * -----`:_ b Requires ASCII encoded keyboard and monitor to o\y make fully configurable intelligent terminal. Uses 6802 V micro and 6845 controller. Program and character generator (7 X 9 matrix with descenders) in two 2716 EPROMs. Full scrolling at 9600 baud with 8 switch selectable rates. RS232 interface. Bare board with 2 EPROMS and program listing - 137 Standard Ranges in a variety of sizes and stylings available £48 plus VAT. Assembled and tested -£118 Send for 10-14 days delivery. Other Ranges and special scales can be for details or CWO to: made to order. Full information from: A M Electronics HARRIS ELECTRONICS (London) Wood Farm, Leiston, Suffolk IP16 4HT Phone: 01-837 7937 ANI 138 GRAY'S INN ROAD, W.C.1 ELECTRONICS Tel: 0728 831131 Telex: 892301 CIRCLE 49 FOR FURTHER DE'T'AILS. CIRCLE 40 FOR FURTHER DETAILS.

111hF:I.E.,11-OH1.1) 1)V(.1-:Al l

www.americanradiohistory.com MULTIMETERS Hand-held

multimeters PM2518lcmulcmmcer PHILIPS Third and final article in our digital multimeter series brings together price and performance data for hand-held d.m.ms on the UK market. We found many more hand-held verter and display drive on one The latest device ZN451 is the digital multimeters than we chip listed on page 76 of October's most useful. Not only is it a single initially thought were on the mar- article, a number of others are chip circuit requiring only passive ket. The large number found - available, some as original external components (for a basic over 160 - is partly due to the approaches to the application, voltmeter), but because it uses a widespread practice of 'own - some as exclusive custom - digital auto -zero mode it obviates label' branding of products made designed chips jealously the need for the capacitor to store in the Far East, chiefly in Korea guarded, and some simply on a error voltage. And additional sig- and Japan but also in Taiwan, second -source basis. nal, conditioning circuitry which results in many instru- National Semiconductor's four andded to the main circuit can be Multimeters built into test ments having identical or very c-mos circuits are of the pulse included within the auto -zero probes are no longer new but similar functions, ranges, errors modulation kind requiring no loop to guarantee zero reading for perhaps a pen -style one that and construction. We summarize external reference components, zero input. A voltmeter evalua- clips into the pocket will be. their data in this month's table. though a voltage reference is tion kit which includes p.c.b., Middle photo: Japan's Soar As with last month's tables for needed. Linearity is within display and conditioning i.cs, is 3200 (from HI); lower photo: bench and systems multimeters, ±0.05%, of full scale, typically available (£29.50), though the another Japan -made probe we have singled out the basic 0.025%. Two are microprocessor chip is equally suitable for applic- sold under various names direct voltage range as being the compatible, with bcd outputs for ations such as thermometry and (Anders, Pantec, Beckman, most telling in terms of sensitivity 3Z or 3 -digit operation, while two transducer bridge interfacing. Häwa, Hioki, Taylor); upper and error; the function converters others offer 31 or 3 -digit multi- photo: not yet available. invariably degrade error specifi- plexed seven -segment outputs cation. October's issue gave the with a reading speed of either 5 or errors that would arise in using 2.5 per second, respectively. non -sinusoidal waveforms on Of Ferranti's interestingly alternating ranges without the wide range of converters that use of a 'true r.m.s.' converter, includes ramp, successive although if the crest factor of the approximation, tracking, flash, waveshape being measured is charge balancing and dual -slope known corrections can often be types, the 31 -digit dual -slope applied. (A rectangular wave with chips are most applicable to a pulse duty cycle of 40% can be voltmeter design. ZNA116 and measured without correction, 216 both drive multiplexed seven - provided adequate bandwidth is segment l.e.d. displays, con- available, as the table on page 74 sume about 50mW but require of that issue hints.) Those meters additional analogue circuitry for that measure the mean value but the integrator and comparator display a scaled r.m.s. value for sections. sine waves will give the reading in column two of October's table for a one -volt peak input. So column Bench digital multimeters in addition to page 61/2 table, November issue. is is col. two one what sensed, Maker Digits Model Basic Sens. Basic Ç Crest Res. µP ' Other what is indicated, and col. three price d.v. error(1) a.v.(2) factor (3) (4) (5) the heating equivalent value, with 4z 20kHz diode test the error in col. six. Crest factor, AOIP 5120 104V 0.05%+1 - (Danesbury) 5121 338 10 0.03%+1 400 4 G£261 usually taken as a measure of 5122 474 1 0.03%+1 400 4 4 dB, G£255 deviation from a sine shape, is peak value divided by r.m.s. Delristor 4 Exis 200 850 1011V 0.03%+1 20kHz 3 V Safety cert. value (form factor, less often Hioki 32 3209 342 100µV .2+1%+1 20kHz - V C, battery used, is r.m.s. value divided by (Doran Smith) 4- 3222 874 10 .04%+2 200k 2,4,7,12 f,G. mean value). In the table the sec and row refers to both triangle Rohde & 4l UDL4 365 10µV 0.03%+2 20kHz 5 charges and sawtooth waveforms, and the Schwarz fourth row to both rectified and 1. Figures are direct voltage ±(reading%+digits)or±(reading+f.s.)%, over 12months unless otherwise noted. 90° -chopped sine waves. 2. Level limit may differ e.g.-1dB, 1%, 3dB 3. 4: four -wire measurement, hi/lo: high and low test voltages As well as Intel devices com- 4. Microprocessor functions, see November table (9: variance, standard deviation, and r.m.s.) prising analogue -to-digital con- 5. G: GPIB interface, B: bcd/parallel interface, C: capacitance, dB: decibels ELECTRONICS & WIRELESS WORLD DECEMBER 1984 43

www.americanradiohistory.com MULTIMETERS

Hand-held digital multimeters

Brand Model Price Type Basic f Ranges: (note 4) Device Cont. Other (ex VAT) (digits)' error2 (note 3) min d.v. I R test' (audio)` (note 7) Amprobe AM4 171 3'/, 0.8% 400Hz 200mV 5 6 R - T (Canadian Inst.) AM5 124 B 1% 400 200 3 3 - - h. duty AM7 97 R 0.05% similar to Soar ME550

AM8 112 R 0.5%+2 similar to ME540 AM9 126 R 0.35% similar to ME530 range extending adapters available `Alta 1' KD25C 32 31/,S 1+.2% 2V 3 4 - - KD30C 37 R .8+.2% 200mV 6 6 - - KD55C 47 R similar to KD30 except 10A range KD305 31 S 0.8% 500Hz 2V 4 4 - - KD615 40 R 0.8% 500 200mV 5 6 hFE - Anders SK6010 45 21/28 0.5% similar to Lutron 6010 SK6500 49 31/2R .5%+% similar to Ishii DM3350 SK6590 54 B .5%+4 500Hz 2V - A4 - <19Q probe SK6507 67 R .5+.2% 500 200m 3 A5 V <1.9Q hold SK6330 89 B similar to SK6507 but with button switches AOIP(Danesbury)5102 115 3'/2R 0.1% 1kHz 200mV 5 6 V - cmos 5103 172 R 0.1% data as above cf:4 5105 129 R 0.1% data as above V AVO 2000 68 31/2S 0.25% 450Hz 2V 2 3 R -3 hi/lo 704(0) 37T B 0.1% data as above Ishii DM2350 57 31/213 .8+.2% 500Hz 200mV Al A4/5 - <2Q hi (Altaras) DM3350 42 31/2R .5%+4 500 200 A2 A4/5 - <1.94 hi/lo Iskra Digimer30 140 3'/2R 0.5% 4kHz 200mV (6) 5 - - I.c.d Hioki 3200 69 3'/2R .35% 5kHz 200mV 5 A6 V V hold (Dorman Smith) 3205 173 R .3+.1% 1k 200 A4 A6 - - 3207 50 B .7%+4 500 200 A2 A5 V V hi/lo 3208 75 B as 3207 but with calculator (shared display)

ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com Hand-held digital multimeters

Brand Model Price Type Basic f,,,, Ranges: (note 4) Device Cont. Other (ex VAT) (digits)' error' (note 3) min d.v. I R tests (audio)6 (note 7) Häwa 3201 42 31/2S 0.5%+4, similar to model by Anders, Beckman, Pantec, Seiko (Kelgray) 3212 58 R 0.5%+4, similar to model by Beckman, Ishii, Pantec 1350 30 B 0.5%+4 similar to model by Anders, Beckman, Seiko, etc 58 B .8+.2% similar to Ishii DM2350 but with 20A

Kane -May KM28 55 3'/2 0.5% 400Hz 200mV 6 6 1mA <30Q hFE,C (E.T.I.) Similar to Metex 3500

Keithley 128 145 3'/2R 0.5% 500Hz 2V 1 4 R V limits 129 79 31/2R 0.5% 500 200m 5 5 R 130A 115 R 0.25% 500 200 5 5 R 132 225 R 0.25% 500 200 4 5 R cf:3,T 135 265 4'/2R 0.05% 20k 2V 2 5 R 136 175 41/2R 0.04% 1k 200mV A3 A6 1mA <18Q hold Kwang Duk (Kingdom) See Altaras listing Kikusui (Telonic) 1506 69 31/28 .5%+2 500Hz 200mV 6 A6 - <20Q man. opt.

Kyoritsu (Robin) K1003 89 31/2B 0.5% 200mV 6 5 T opt Lascar 2020 29 3'/2S 0.6% 500Hz 2V 4 4 Lutron 6010 40 3'/2B 0.5% 500Hz 200mV 5 5 (Contemp) 6011 50 B 0.5% 500 200 5 4 hFE 6012 60 B 0.5% 500 200 5 5 hFE,hl/Io 70 B 0.5% 500 200 3 4 400A For under £30 this 6014 evaluation a Metertech - See Lutron kit provides dvm Metex (HI, 3500ser 34-45 3'/2R 0.5% 400Hz 200mV 6 6 imA opt options with f.s. range of 2mV. Lawtronics 3501 ser 37-51 R 0.1% 400 230 6 6 1 opt C,hFE 3 5 V Metrix 522 67 31/2R 0.5% 45Hz 200mV Correction. Because of a last-minute R 0.2% 450 200 4 6 V V (Sifam) 562 95 breakdown in facsimile reception of 563 155 R 0.1% 3k 230 5 6 V V dB cf: 575 175 R .05%+2 20k 200 3 6 V freq cf: proofs certain pages of the November MIC 3300A 42 3'/2R 0.8% 500Hz 200mV 6 6 .2mA hFE no ac issue went unchecked. Readers will 7000 150 4'/2 0.05% 3kHz 200 6 6 G,f have spotted the most embarrassing 6000Z 46 3'/2R 0.8% - 200 6 6 .2mA hFE errors (e.g. zero 'ironings' instead of Micronta 22189 35 3'/2R 0.2% 10kHz 2V 3 4 crossings in the caption to Datron's (Tandy) 22191 45 R 0.2% 10k 200mV 3 6 <300 Autocal multimeter on page 65) but 22193 65 R 0.1% 10k A A those in the tables are less obvious. Norma 1214 102 3'/2R 0.4% 400Hz 200mV 5 6 R Please correct Brown Boveri's 2110 5k 200 5 6 V <50 (Cropico) 1216 128 R 0.2% basic error to 0.05%+1, and Farnell's Pantec Brisk 46 3'/2R similar to Ishii DM3350 141 error to O. 03%+2. A zero slipped (Solent, Zip 49 B .5%+4 500Hz 2V - 4 similar to Anders SK6590 Cirkit) 2001 99 B 0.2% 30k 200mV 6 7 V - osc,C in the R & S UDS5 error but its best Philips 2517 180 4R .2+.05% 20kHz 100mV 2 5 1 mA cf:2 figure over 12 months is 0.009%+1, .(Pye Unicam) 2518 165 A4'/2R .1+.02% 20k 200 5 6 1mA cf:9 and its rated a.v. max is 200kHz with Racal Dana 2000 188 3'/2R 0.2% 10kHz 200mV 6 7 - -T a crest factor of 5.5 for true r. m. s. Robin 0M100 59T 31/28 0.8% similar to Lutron 6011 readings. 0M120 691 R 0.25% similar to Hung Chang 5010 31/2B for Kyoritsu K1003 89T data 4z digit meters are usually set 0.1 % 20kHz similar to Hung Chang Rohde & Schwarz UDL33 157 3'/2B to display their maximum Ross 186 62T 31/2P 0.8% 500Hz 200mV 6 6 - hFE,G 187 55T data as above value for photography but this 188 571 3'/2B 0.8% similar to Lutron 6011 Fluke display could be mis- 189 881 data as above, Similar to Soar 8050 leading in suggesting full five - Sanwa Plug-in adapters available for circuit checks, .n, T, C digit capability. (Servo & MD180 85 31/2 .2+:15% 200mV 4 6 hi/lo Electronics) MD250 106 R 0.35% 200 4 A6 V LD510 96 R .7+.2% 200 A2 45 optional hi/lo

LD520 147 R .5+.2% data as above hFE LD530 160 R .5+.2% data as above C FD750 203 41/, .06+.03%200 3 6 R Siemens B1002 125 31/2R 0.2% similar to Norma 1216 B1008 R 0.4% similar to Norma 1214 Sifam 2200 43 31/2 .3%+2 700Hz 2V 4 5 Simpson 470 120 372R 0.15% 200mV 5 6 (Bach Simpson) 474 189 4'/2R 0.03% 200 5 5 V Soar ME531' 56 3'/2R 0.8% 200mV A2 A5 V V cmos (House of ME530 49 R .35%+2 500Hz 200 5 A6 .6mA <20 cmos Instruments, MEMO 39 R .5%+2 500 200 2 A6 .6mA <20 *Maplin, ME550 37 R .5%+2 500 200 1 A6 <20 cmos tEagle, 3025 149 B 0.25% 500 200 A6 A6 .6mA <20 comparator ttRoss) 3030 99 data as above but without comparator function 3100 39 B .5%+3 500 200 - A6 <150Q probe 3400 41/26 .1%+2 500 290 A5 A6 1mA <20 80251- 75 3'/2R 0.2% sold as Engle TS4000 80501.1. 88 0.8% sold as Rc.ss RE 089 Taylor (Thorn) TD20 39 31/2S Seiko probe to 13S4743, data as Anders SK6590 Thandar 354 40 31,5 0.75% 500Hz 2'/ 4 4 V Weston 6100 3'/2B 0.5% 1kHz 1110mV 4 5 V <10 <1V,2V (Electroplan), 7310 165 B 0.5% 1k 290 4 6 <10 <1V,2V 7320 85 R 0.1% 1k 24V - A3 V <100 TMK 3300 70 3'/2R 0.4% 400Hz 200mV 6 7 - cmos (Harris) Two further modelstba. 0.5% 450 200 A A Notes. 1: B button, R rotary, S slide. 2 Basic (d.v.) error is ± (reading % +1 digit), or ±(rdg + f.s.) %, unless shown otherwise. 3 f,,,, (a.v.) limits may differ. 4: Minimum range shown for d.v.. upper range typically 100d.v. and 750 a.v. Ranges for I, R are decades except for top I, normally limited to 10A. 5: Normally scaled to read forward voltage. R means maker suggests 2k4 range. 6: Audible signal for continuity, maximum resistance value given where known. 7: Crest factor (cf) given for true rms meters. G conductance range, C capacitance, T temperature. hi/lo R switch gives >0.7V or <0.3V for in -circuit resistance measurement. For cmos devices battery life is quoted as 500-2000h. ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com MULTI STANDARD MODEM

by Richard Lambley Multi -standard modem Connections and modifications

Fig.1. Using the RS423 port Several readers have asked for notch in the five -pin domino con- BBC Micro users who have added of a BBC Micro. At the fuller information about connect- nector goes in on the side nearer the interface for the autodialler modem, it is cheaper to fit a ing the modem to the BBC Micro, the cassette port. may find it less untidy to use six -pin DIN socket rather which lacks a full RS232 inter- Notice that the RTS line from spare inverters in that. than the p.c.-mounting D - face. Figure 1 shows pin details of the computer is not used: this is However, there are times when connector: connections the computer's RS423 connector to avoid the risk of line drop when you may want to hold on to the shown are those found on and the corresponding terminals the computer turns its attention line regardless; for example, certain commercial modems. on the modem. The polarizing to other matters, as it does during when exchanging files at 1200 disc or tape filing operations. baud with someone else. Revers- RTS is best tied high at the ing the direction of transmission modem either by linking RTS to can be made less hazardous by DSR, or (if IC7 has been omitted, means of two diodes and the use as it may be when a full. RS232 of a spare contact on S,. This pro- interface is not required) by link- vides an extra 1200/75 mode in RGB RS 123 CASSETTE ing pins 13 and 14 on ICS. which the modem will continue to Figure 2 shows a modification hold the line even when there is BROWN (TEN to take care of the opposite prob- no carrier (Fig.3).

-27 +® 4` REO (RKOI lem, a possible failure by the To insure against possible a, modem to disconnect the line instability in the auto -answer cir- BLACK IGNOI when the user logs -off a viewdata cuit, it is worth adding a high system. This may occur if a noise value resistor between pin 7 of YELLOW IC TS) on the line is interpreted by the IC11 and the OV rail. The value

N or of MODEM Pcct. board modem as a burst of carrier. is not critical; anything between Icaponºnt side) The two inverters form a mono - 1 and 10MQ seems to work suc- O O O O OIO O 0 0 0 ojS 0 0 0 0 0 o o 0)3 stable which triggers when the cessfully. line -seize relay drops out. Until A further small addition to the board may be needed if you have been supplied with a 40147 for IC,. This device is not a direct 1[18 Break original replacement for the 74HC147 1/44071 ,.8 connection since it has a connection to pin To C, etc 15. If you fit a 40147, be sure to tie pin 15 to the 0V rail. Failure to +5V do this may produce puzzling

2p2 tant. To effects. One such modem I have original seen appeared to be working all circuit right except in the Bell 103 orig- BAW62 IC8 inate mode (for which all inputs to 25 IC, are pulled high): it turned out 4M7 100n IF 1 Cö then that IC, was driving the 10M 22r BAW62 mode -select inputs of the Am7910 Fig.2 . An additional monostable with 2MHz square waves. ensures that the line is dropped cleanly after a Viewdata call. To C17 Pin 5 Auto -dialler

To C3 An enhanced version of the auto - dialler (October issue) can be the monostable times out (its downloaded free of charge from period is a second or two) RL1 the Microweb bulletin board in cannot close again. The purpose Stockport on 061-456 4157 (300 of the diode pump circuit is to baud CCITT). The file is stored as trigger the monostable if a suc- Ascii text: when you have saved it cession of rapid transitions you should reload it using *EXEC s1 / 10 1200/75 occurs on ICS's carrier -detect rather than CHAIN. The program System" To IC15 output: this will make sure that includes one or two improve- Extra contact Pin 12 etc. brought into use the modem does not try to demo- ments, among them a facility for dulate dialling tone. inserting pauses between digits Fig.3. An extra mode for file exchange at 1200 baud. Several spare inverters are to to give time for a further dialling be found on the p.c.b. though tone to appear. 46 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

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SE5FP31 55.00 UPC1191V 1.50 LC7130 3.50 SN76003N 1.95 TAA700 1.70 TDA1004A 3.25 CRE1400 25.00 M14-100KA 55.00 T937 85.00 UPC1350C 2.95 LC7131 5.50 SN76013N 1.95 TBA120AS/B/C/ TDA1006A 2.50 CV429 89.00 M14-100LC 45.00 T948N 85.00 UPC1353C 2.45 LC7137 5.50 SN76023N 1.96 1.00 TDA1010 2.15 CV1450 35.00 M17-151GVR 175.00 T948H 65.00 SA/SB/T4U UPC1365C 3.95 LM324N 0.45 SN76033N 1.95 TBA231 1.25 TDA1035 2.50 CV1526 19.00 M17-151GR 175.00 V3191 59.00 LM380N 0.95 SN76110N 0.89 TDA1037 1.95 UPC2002H 1.95 CV2185 15.00 M19-100GY 55.00 V4150LC 55.00 TBA395 1.50 555 0.35 LM383T 2.95 SN76115N 1.25 TBA396 0.75 TDA1170 1.95 CV2191 19.00 M19 -100W 45.00 V42548 65.00 M51513L 2.30 TDA1190 2.15 556 0.42 CV2193 15.00 M19-101 GR 55.00 V4274GH 65.00 SN76131N 1.30 TBA440N 2.55 723 0.50 M51515L 2.95 SN762260N 2.96 TDA12700 3.95 CV2328 65.00 M19 -103W 55.00 V4283W 65.00 TBA4800 1.25 741 0.35 M515211. 1.50 SN76227N 1.05 TDA1327 1.70 CV5119 85.00 M23-110GH 55.00 V5002LD 65.00 TBA510 2.50 747 0.50 MB3712 2.00 SN76533N 1.66 TDA2002 1.95 CV5320 85.00 M23 -111W 55.00 V5004GR 59100 TBA5100 2.50 748 0.35 MC1307P 1.00 SN76544N 1.96 TBA520 TDA2020 2.95 CVX389 55.00 M23-111GH 55.00 V5004LD 59.00 1.10 7805 MC1310P 1.50 SN76570N 1.00 TBA5200 TDA2030 2.80 0.65 D9-110GH 39.50 M23-111 LD 55.00 V6001 GH 85.00 1.10 7808 0.80 MC1327 0.95 SN76650N 1.15 TBA530 1.10 TDA2522 1.95 D9-120 45.00 M23-112GM 55.00 V6006GH 65.00 7815 0.55 MC13270 0.95 SN76660N 0.80 TBA5300 1.10 TDA2523 2.95 D10-210GH 45.00 M23-112GV 55.00 V6007DP31 59.00 D10-210GH68B 85.00 M23-112GW 55.00 V6007GW 85.00 B0204 0.70 BFR39 0.23 RCA16335 0.80 D10-210GH72 115.00 M23-112KA 55.00 V6008GW 59.00 SEMICONDUCTORS 00222 0.46 BFR40 023 SKEW 1.45 D10-230GH 35.00 M23-112LD 55.00 V6008W 65.00 AAY12 0.25 BC174 0.09 BD223 0.59 BFR41 0.28 TIP29 0.40 D10-230GM 35.00 M23 -112W 55.00 V6034WA 59.00 AC126 0.45 BC174A 0.09 BD225 0.48 TIP29C 0.42 M24-120GM BFR81 025 D10-293GY/90 55.00 59.00 V6048CLA 59.00 AC127 0.20 BC177 0.15 BC232 0.35 TIP30C 0.43 BFR88 0.30 D13-27GH 49.50 M24-120GR 59.00 V6048F 65.00 AC128 0.28 BC178 0.15 BD233 0.35 TIP31C 0.55 BFR90 1.50 D13-30GH 49.50 M24-120LC 59.00 V6048J 49.00 AC128K 0.32 BC182 0.10 8D234 0.35 TIP32C 0.42 BFR91 1.75 D13-33GM 49.00 M24-120WAR 59.00 V6052GH 85.00 AC141 0.28 BC182LB 0.10 BD236 0.49 8E742 TIP33B 0.75 D13-47GH/26 55.00 M24-121 GH 55.00 V6052GR 65.00 AC141K 0.34 0.35 BC183 0.10 BD237 0.40 BFT43 TIP348 0.75 D13-47GH/34 55.00 M24 -1211C 59.00 V60648LA 65.00 AC142K 0.30 BC183L BD238 0.40 0.35 TIP41A 0.09 BFW92 0.85 0.45 013-51 GL/26 85.00 M24-121 WA 59.00 V60648P31 55.00 AC176 0.22 BC184LB 0.09 BD242 0.85 TIP41C 0.45 013-51 GM/26 85.00 M28-11 LA 49.00 V6064CLA 55.00 AC176K 0.31 BFX29 0.30 BC204 0.10 80246 0.75 BFX84 TIP42C 0.47 D13-450GH/01 55.00 M28-12GH 55.00 V6069GH 55.00 AC187 0.25 BC2078 8D376 0.32 0.26 0.13 BFX85 0.32 TIP47 0.85 D13-471GH/26 55.00 M28-12LC 55.00 V6070P31 49.00 AC187K 0.28 BC2088 0.13 BD410 0.85 TIP120 0.60 D13-550GH 85.00 M28-13LC 49.00 V7016A 65.00 AC188 0.25 8C212 0.09 BD434 BFX86 0.30 0.65 BFX88 0.25 TIP125 0.85 D13-600GM 59.00 M28-13LG 49.00 V7030 59.00 AC188K 0.37 BC212L 0.09 BD437 0.75 1I0142 1.75 BFY50 0.21 D13-610GH 59.00 M28-13GR 49.00 V7031GH 59.00 AD142 0.79 BC212LA 0.09 BD438 0.75 TIP161 2.95 M28-13WA BFY51 021 D13-610GM 59.00 49.00 V7031 /67A 59.00 AD143 0.82 BC213 0.09 BD520 0.85 TIP2955 0.80 D13-611 GH 59.00 M28-131 GR 55.00 V7035A 49.00 AD149 0.70 BC213L 0.09 BD538 0.65 BFY52 0.25 BFY90 0.77 TIP3055 0.55 D13-611 GM 59.00 M28-132GM 55.00 V7037GH 45.00 A0161 0.39 BC214 0.09 BD597 0.95 TIS91 M28-133GH BLY48 1.75 0.20 D13-630GH 59.00 55.00 V8004GR 65.00 AD162 0.39 BC214C 0.09 B0701 1.25 TV106/2 BR100 0.28 1.50 014-120GH08 65.00 M31-100GH 55.00 V8008GH 65.00 AD161 /2 0.90 BC214L 0.09 BD702 1.25 2N2110 4.50 D14-150GH 75.00 M31-101GH 55.00 V8010A 85.00 AF106 0.50 BC237B 0.09 BD707 0.90 BR101 0.49 BR103 0.55 2N2219 0.28 O 14-150GM 75.00 M31-182GR 55.00 2BP1 9.00 AF114 1.95 BC238 0.09 BDX32 1.50 2N2905 0.40 M31-182GV BRC4443 1.15 D14-172GH/84 59.00 53.00 3BP1 13.50 AF121 0.80 BC239 0.12 BDY57 1.65 2N3053 0.40 M31 -183W BT100A/02 0.85 D14-172GR 55.00 55.00 4EP1 30.00 AF124 0.85 BC251A 0.12 BF115 0.35 2N3054 0.59 M31 -184W BT106 1.49 D14-172GV 55.00 85.00 3H'/OBM 55.00 AF125 0.35 BC252A 0.15 BF119 0.85 2N3055 0.52 BT116 1.20 014-173GH 55.00 M31-184GH 65.00 50P1 9.00 AF126 0.32 BC258 0.25 BF127 0.39 2N3702 0.12 0T119 3.15 D14-173GM 53.00 M31-1841,31 65.00 58HP1 30.00 AF127 0.40 BC258A 0.39 BF154 0.20 2N3703 BT120 1.85 0.12 D14-173GR 55.00 M31-185GH/VR 89.00 5BHP1FF 30.00 AF139 0.40 BC284 0.30 8E158 0.22 BU705 122 2N3704 0.12 014-181 GH/62 85.00 M31 -186W 69.00 58HP31 30.00 AF150 BC300 0.30 8E160 027 0.60 BU108 1.69 2N3075 0.12 D14-181GH/98 65.00 M31-190GH 55.00 5CP1 10.00 AF17N 1.95 BC301 0.30 8E167 0.27 2N3706 BU124 1.25 0.12 O 14-181GJ 55.00 M31-190GR 55.00 6EP7/S 39.00 AF239 0.42 BC303 0.28 8E173 0.22 2M3708 M31-190LA BU125 125 0.12 D14-181GM 53.00 55.00 13BP1 13.50 AU107 3.50 BC307B 0.09 BF177 0.38 2N3733 9.50 D14-181GM50 59.00 M31 -190W 59.00 138P4 17.50 AU106 3.25 BC327 0.10 BF178 0.28 BU126 1.80 BU204 1.55 2N3773 2.75 014-181W 55.00 M31-191 GH 59.00 170WP4 25.00 AU110 4.50 BC328 0.10 BF179 0.34 M31-191GR BU205 1.30 2N3792 1.35 D14-182GH 59.00 59.00 32J/1085 89.00 BC107A 0.11 BC337 0.10 BF180 0.29 M31-191GV BU208 1.39 2N4427 1.50 D14-182GM/98 65.00 55.00 880/89B/89D/89L 15.00 BC1078 0.11 BC338 0.09 BF181 0.29 M31 -191W BU208A 1.52 2N4444 1.15 D14-2000E 89.00 59.00 1273 39.00 BC108 0.10 BC347A 0.13 BF182 0.29 M31 -192W 59.00 BU208D 1.85 2N5294 0.42 014-200GA/50 85.00 1564 39.00 BC108A 0.11 BC461 0.35 BF183 0.29 D14-200GM 75.00 M31-195GH 59.00 1844 BU326 120 2N5296 0.48 -2N5298 45.00 BC108B 0.12 BC478 020 8E184 0.28 D14-210GH 75.00 M31-210GH 59.00 9442E1 80.00 BC109 0.10 BC527 0.20 BU407 124 0.60 BF185 0.28 2N5496 D14-270GH/50 75.00 M31 -220W 59.00 95447GM 75.00 BC109B 0.12 BC547 0.10 0.11 BU500 225 0.85 8E194 2SA715 0.80 D14 -310W 110.00 M31-270GY 65.00 95449GM 75.00 BC109C 0.12 BC548 0.10 BF195 0.11 BU526 1.90 BUSBY 2.25 2SC495 0.80 D14-320GH 85.00 M31 -271P31 65.00 7709631 78.50 BC114 0.11 BC549A 0.10 8E196 0.11 M31 -2710W BUY69B 1.70 2SC496 0.80 D14-320GH/82 85.00 65.00 BC116A 0.15 BC550 0.14 BF197 0.11 D14-340GH/KM 45.00 M31 -271W 65.00 ELECTRO -OPTICAL BC117 0.19 BC557 0.08 BF198 0.18 MJ3000 1.98 2SC1096 0.80 014-340KA 45.00 M36 -12W 75.00 95025 25.00 BC119 0.24 BC557B 0.08 8E199 0.14 MJE340 0.40 2SC1106 2.50 2SC1172Y D16-100GH 85.00 M36-141LA 75.00 95588 BC125 0.25 BC558 0.10 BF200 0.40 MJE520 0.48 2.20 25.00 MPSA13 0.29 2SC1173 1.15 016-100GH/65 89.00 M36-141LG 75.00 9677M 22.00 BC139 0.20 BCY33A 1.80 BF241 0.10 D16-100GH/67 65.00 M36-141W 75.00 BC140 MPSA92 0.30 2SC1306 1.00 04231 SAM 19.00 0.31 BD115 0.30 BF245 0.30 O 16-100GH67A 75.00 M36-17OLG 75.00 BC141 0.25 BD116 0.80 MRF237 3.45 2SC1307 1.50 BF259 0.28 MRF450A 12.50 2SC1364 0.50 O 16-100GH/79 69.00 M38-100GR 65.00 WIREWOUND RESISTORS BC142 0.21 8D124P 0.59 BF257 0.28 D16-1000H/79A 75.00 M38-101 GH 65.00 BC143 0.24 MRF453 17.50 2SC1449 0.80 BD131 0.42 BF258 0.28 2SC1678 D16-100GH97 65.00 M38-103013 65.00 BC147 0.09 0.42 MRF454 23.50 1.25 4 Watt 506-10K 0.20 BD132 BF259 0.28 2SC1909 D18-130GH 85.00 M38-113GH 65.00 BC1478 0.09 BD133 0.40 MRF455 17.50 1.45 7 Walt 047-22K BF271 0.28 2SC1945 2.85 018 -160tH 89.00 M38 -120W 65.00 0.20 BC148A 0.09 BD135 0.30 6E273 MRF475 2.50 0.18 2SC1953 0.95 021-10GH 65.00 M38-120WA 65.00 105-15K BC148B 0.09 BD136 0.30 MRF477 10.00 11 Wan 0.25 BF336 0.34 2SC1957 D21-10GJ 69.00 M38-121 GR 85.00 BC149 0.09 80137 0.32 OC16W 2.50 0.80 111-15K BF337 0.29 2SC1969 1.95 021-1010 89.00 M38-121GHR 65.00 17 Wan 0.30 BC157 0.12 BD138 0.30 8E338 0C23 1.50 0.32 2SC2028 1.15 087.6 35.00 M38-121LA 85.00 BC158 0.09 130139 0.32 0C42 0.55 VALVE AND BF355 0.37 2SC2029 1.95 DB7-36 45.00 M38-121 WA 85.00 CRT BASES BC159 0.09 BDD140 0.30 BF362 0C44 0.75 0.38 2SC2078 1.45 DG7.32 45.00 M38-122GH 65.00 B5D 5.50 B130 0.50 BC160 0.28 BD144 1.10 BF363 0.135 OC45 0.55 2SC2091 0.85 DG13.2 45.00 M38-122GW 85.00 B7G BC161 0.28 0E371 OC70 0.45 0.15 814A 3.00 BD150C 0.29 0.25 DH7.11 M38 -140LÁ 85.00 BC170B 0.15 BD159 0.65 0071 0.55 2SC2098 2.50 95.00 B7G SKID 0.25 12PIN CRT 0.95 BF394 0.19 2SC2166 DH7.91 M38-141LA 85.00 BC171 0.09 0081 0.50 1.95 45.00 B8G NUVISTOR 80160 1.50 BF422 0.32 2SC2314 DP7.5 M38-142GR 65.00 0.70 2.95 BC171A 0.10 R2008B 1.45 0.80 35.00 BD166 0.55 BF457 0.32 2SC2371 DP7.6 M38-142LA 85.00 B8H 0.70 OCTAL 0.35 BC171B 0.10 R20100 1.45 0.38 35.00 80179 0.72 BF458 0.38 260234 0.50 DP7.11 45.00 M38-340031 65.00 BOA 0.25 SK610 35.00 BC172 0.10 BD182 0.70 8F459 R2322 0.58 0.38 3N211 1.95 O N13.78 35.00 M38-341 GR 65.00 BOA SKT 0.40 UX5 BC172B 0.10 BD201 0.83 BF467 R2323 0.88 1.75 0.86 3SK45 0.70 F15.101LC 49.00 M38 -341P31 65.00 BC172C 0.10 BD202 0.85 8E595 0.23 R2540 2.48 09G 0.75 UX7 1.75 3SK88 0.55 F16-101GM 55.00 M38 -344P39 85.00 BC173B 0.10 BD203 0.78 BF597 0.25 RCA16334 0.90 6106 0.20 CANS 0.30 BY206 0.14 N23WE 2.95 UNE OUTPUT TRANSFORMERS E H T MULTIPLIERS VARICAP TUNERS PUSH DIODES BY208-800 0.33 64001 0.04 BUTTON UNITS BY210-800 0.33 DECCA 100 7.95 ITT CVC20 8.35 ELC1043/05 MULLARD 64003 0.04 8.66 DECCA, ITT, CVC20 6WAY 7.95 AA119 0.08 BY223 0.90 N4004 DECCA 1700 MONO 9.95 ITT CVC30 8.35 ELC1043/06 MULLARD 0.05 8.85 ITT CVC57 WAY BA115 0.13 BY298-000 0.22 DECCA 1730 8.95 PHILIPS 08550 8.98 U321 10.19. N4005 0.05 8.25 PHILIPS G8 (550)6 WAY 14.49 BA145 0.18 BY299-800 0.22 N4007 0.06 DECCA 2230 8.25 RANK T20A 6.91 U322 8.25 BA148 0.17 BVX10 0.20 N4148 0.02 GEC 2040 0.95 THORN 3000/3500 7.57 BA154 0.08 BVX36-1500 0.20 N4448 0.10 GRUNDIG 1500 15.45 THORN 8500 5.80 POTENTIOMETERS 20MM QUICK BLOW FUSES BA156 0.15 GRUNDIG 5010-6010, BYX38-6005 0.60 N5401 0.12 2222.5011-6011 1345 THORN 9000 8.00 STANDARD BA157 0.30 VERTICAL POTS 0.12 100MA Bp each BYX55-600 0.30 N5402 0.14 8.20 UNIVERSAL TRIPLER 5.45 MIN. VERTICAL BAX13 0.04 ITT CVC30 POTS 0.12 200MA-5AMP 5p each BYX71-600 1.10 N5403 0.12 8.25 SANDARD BAX16 0.06 BZY95C30 0.35 PHILIPS G8 8.50 N5406 0.13 HORIZONTAL POTS 0.12 BB105B 0.30 CS48 4.50 PHILIPS G9 8.99 REPLACEMENT N5407 0.16 MIN. HORIZONTAL POTS 20MM ANTI SURGE FUSES BT151 0.79 CS10B 8.45 PHILIPS G11 13.39 0.12 N5408 0.16 ELECTROLYTIC CAPACITORS CONVERGENCE PRE-SETS BY126 0.10 0A47 0.01 PYE 725 10.95 0.30 ITT44 0.04 SLIDERS LOG 0.48 100MA-800MA 15p each BY127 0.11 0A90 0.05 RBM T20A 12.40 DECCA 301400-400/350V) 17923 0.15 2.85 SLIDERS LINEAR 0.48 '1A-5AMP 12p each BY133 0.15 OA91 0.06 TT2002 0.10 TANDBERGE 90° 11.15 DECCA 80/1001400/350V) 2.99 BY164 0.45 TELEFUNKEN 711A OA95 0.08 11.15 DECCA 1700 SPARES BY176 1.20 OA202 0.10 THORN 1590 9.50 (200-200-400-350V) 3.55 & AIDS THORN BY179 0.83 IN21DR 2.95 ZENER DIODES, 8000 9.20 GEC 2110 (600/300V) 2.25 FOAM CLEANSER 0.79 PUSH PULL MAINS SWITCH BT182 0.55 THORN 9000 IN23B 2.95 9.95 ITT CVC201200/400VI 1.80 FREEZE IT 0.82 (DECCA, GFC, RANK, THORN BV194 0.35 BZX61 Series 0.15 THORN 9800 IN23C 2.95 22.40 PHILIPS 081600/300V) 2.25 SOLDA MOP 0.64 ETC.) 1.02 BY199 0.40 THORN MAIN TRANSFORMER I623ER 2.95 BZY88 Series 0.10 PHILIPS G9 (2200/63V) 1.19 SWITCH CLEANER 0.79 PYE IF GAIN MODULE 6.99 3000/3500 9.70 PHILIPS G11 (470/250V) 2.35 WD40 1.25 ANODE CAP 1275V) 0.69

ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com aucut[4aa PHONE P. M. COMPONENTS LTD TELEX 0474 813225 SELECTRON HOUSE, WROTHAM ROAD 966371 3 LINES MEOPHAM GREEN, MEOPHAM, KENT DAI3OQY PM COMP ahm1

M8161 6.50 OS150/15 6.95 UF41 1.15 2K26 95.00 6ÁO5 1.50 6H3N 1.10 12J7GT 0.70 8298 14.50 A SELECTION FROM OUR M8162 5.50 0S150/30 1.15 UF42 1.15 3A/1078 12.00 6ÁO8 0.85 6H6 1.35 12J7GT 3.50 833A 80.00 M8163 5.50 QS150/45 7.00 UF80 0.80 3A/108A 9.00 6AR8 3.95 6H6GT 1.95 12K5 1.00 866A 4.50 STOCK OF BRANDED VALVES M8190 4.50 0Sí200 3.95 UF89 2.50 3A/109B 11.00 6AS5 1.50 6HS6 4.95 121(761 0.60 872A 27.50 M8195 6.50 OS1202 3.95 UL44 3.50 3A/110B 12.00 6AS6 2.50 6.14 2.15 12K8 1.10 873 60.00 A1714 18.50 EBC41 1.95 EL509 5.25 M8196 5.50 OS1203 4.15 UL84 0.85 3A/141K 11.50 6AS7G 4.50 12SA7GT 1.00 884 5.50 1.50 6.14WA 3.15 A1834 7.50 EBC81 EL519 6.96 M8204 5.60 GS1205 3.95 UU5 3.50 3A/147J 7.50 6AT6 0.75 12SG7 4.75 930 9.95 0.90 6.15 2.50 A1998 11.50 EBC90 61.802 3.66 M8223 4.50 0S1206 1.05 UU7 8.00 3A/167M 10.00 6AT8 1.75 12SH7 1.00 931A 13.95 EBC91 0.90 M8224 2.00 6.16 0.65 A2087 11.50 E1821 8.50 Q51207 0.90 UU8 9.00 3A2 3.95 6AU4 2.00 6J86A 12SK7 1.00 954 1.00 EBF33 2.50 M8225 3.50 3.95 3.95 12SJ7 A2134 14.95 E1822 12.96 OS1208 0.90 UY4I 3.50 3A3A 6AU6 0.95 6JE6C 4.95 0.60 955 1.00 EBF80 0.85 ME1401 29.50 3A4 1.10 12SN7GT 1.85 A2293 6.50 EMI 9.00 081209 2.00 UY85 0.70 6AV6 0.75 6JU8 2.50 958A 1.00 A2426 EBF83 0.85 ME1402 29.50 QS1210 1.50 3AL5 0.95 12S07GT 1.50 1299A 0.60 29.50 EM4 9.00 V235A/1K 6AW8A 2.50 6JS6C 4.95 A2599 66E85 0.95 EM80 0.70 ME1501 14.00 0S1211 1.50 250.00 3AT2 3.35 1.50 1303 3.20 1619 2.50 37.50 668G 6.17 4.15 A2792 EBF89 0.70 EM81 0.70 MH4 3.50 OS1212 3.20 V238A/1K 382 3.00 6BA6 0.95 1307 3.20 1625 3.00 17.50 EBF93 0.95 4.00 6K7G 0.70 A2900 11.50 EM84 1.86 MHLD6 0SM13 5.00 384 7.00 68A7 4.50 13D9 3.20 1626 3.00 EBL1 2.50 ML4 4.50 295. 00 6K8 3.95 A3042 24.00 EM85 3.95 0S1215 2.10 387 4.50 68A8A 3.50 13DE7 2050W 4.50 EBL21 2.00 MS4B 5.50 6606 5.50 2.50 A3283 24.00 EM87 2.50 OS1218 5.00 V240C/2K 3824 10.00 6BC8 1.00 2050 3.95 EC52 0.75 MU14 1.50 225.00 6KM8 2.50 13DR7 2.95 AC/HL/DD 4.00 ENI 8.00 QU37 9.50 3826 24.00 6004 1.50 130717 3545 4.00 EC70 1.75 MZI-100 125.00 V241C/1K 6KT8 2.95 3.50 404A AC/THI 4.00 EN32 13.50 QV03-12 4.95 3828 12.00 6606 1.00 14ST 1.00 10.95 EC80 9.50 N37 12.50 195.00 ACT22 59.75 6691 1.10 QV05-25 1.75 3626 1.50 68E6 0.72 6L1 2.50 17EW8 0.95 927 15.00 AH221 39.00 EC81 7.96 EN92 4.50 N78 9.86 0V06-20 29.50 V2464A/2K 66F5 160 6115 3.15 EC86 1.00 3C4 1.00 17J28 2.75 1927 25.00 AH238 39.00 ESU150 14.95 0A2 0.85 0V08-100 315.00 6BG6G 3.00 6119 3.95 EC88 1.00 3C45 24.00 1803 1.60 4313C 4.00 AL60 6.00 ESU872 25.00 OA2WA 1.50 145.00 V339 3.50 68H6 1.95 6L6GC 2.95 EC90 1.10 3CB6 1.50 19AU4GT 2.50 4328D 9.00 ANI 14.00 EY51 0.80 0A3 2.50 0V2-250045.00 V453 12.00 6BH8 1.50 8L6GCIGE13.95 EC91 5.50 3CN3A 2.50 19G3 17.00 5642 9.50 ARP12 0.70 EY81 1.50 OB2 0.65 OY3-125 49.50 VLS631 10.95 68.16 1.20 616GT 1.15 EC92 1.25 3CS6 0.95 19H4 23.95 5651 2.50 ARP34 1.25 EY83 1.50 0B2WA 1.25 OV4 .250 65.00 VP4B 4.50 6BK4 4.00 61020 0.60 EC93 1.50 19H5 33.50 5654 1.95 ARP35 2.00 EY84 5.95 0C2 2.50 GY4 400 71.95 VP133 2.00 3CX3 2.50 66K7A 1.95 6LF6 4.50 EC95 7.00 1906 9.00 5663 1.95 EV86/87 0.50 0C3 1.50 R10 4.00 VR75/30 3.00 3CY5 1.50 6BM8 0.58 6LJ8 ATP4 2.50 EC97 1.10 2.50 20A2 10.50 5670 3.25 EY88 0.55 OD3 1.70 R16 12.00 VR101 2.00 306 4.50 6BN4 1.65 AX50 5.50 6C8010 12.00 6106 4.95 2001 0.70 5672 4.50 EY91 5.50 0M4 1.00 R17 1.50 VR105/30 1.50 3021A 29.50 6BN6 1.85 AZ11 4.50 ECC32 3.50 6N7 2.50 20LF6 5687 4.50 EY500A 1.50 0M5B 3.00 R18 2.50 VR150/30 1.15 3022 19.50 68N7 3.50 ECC33 3.50 4.50 6N7GT 2.50 5692 3.50 AZ31 2.50 EV802 0.70 0M6 1.75 R19 2.50 VT52 2.50 3E22 49.50 6BN8 2.35 2011 0.95 6CC35 3.50 6P15 1.50 20P1 0.55 5696 2.75 BL63 2.00 EZ35 0.75 0RP43 2.50 R20 1.20 VU29 4.50 3EH7 1.95 6805 0.75 ECC81 1.15 6P25 4.00 20P3 0.60 5704 3.50 BS450 67.00 6240 2.75 ORP50 3.86 R1169 55.00 VU39 1.50 36.17 1.95 6607A 072 6P26 4.00 20P4 5718 6.15 BS810 55.00 CC81 Special 6241 2.75 P61 2.50 RG1-125 4.95 W21 4.50 68L7GTA 3.95 1.95 Quality 1.95 3W4GT 2.50 6P28 2.00 20P5 5725 2.50 BS814 55.00 6280 0.75 P41 2.50 RG1-240A14.50 6818 0.85 1.15 ECC82 0.55 W77 5.00 465516 115.00 607 1.20 21LU8 2.50 5726 1.50 CIK 19.00 EZ81 0.75 PABC80 0.50 RG3-250A 3.50 6BR5 0.70 ECC82 Philips W729 1.00 4-65A 59.00 607GT 1.20 2401 5727 1.95 C3JA 21.00 EZ90 1.50 PC86 0.75 RG3-1250A 6BR7 4.95 39.50 1.50 W739 1.50 4-250A 85.00 6R7G 3.15 2516GT 1.75 5749 2.50 F6064 2.95 PC88 0.75 35.00 6BR8 2.15 ECC83 0.65 X24 1.00 4832 19.50 6S4A 1.50 25806 1.75 5750 1.85 C11ó8 5i.95 FW4/800 2.95 PC92 3.50 RK2K25 62.50 66R8A 2.15 ECC83 Brimer/ X66/X65 4.95 4807A 1.75 6S7 5751 2.95 C112G 70.00 G55/1K 9.00 PC97 1.10 RG4-1000 10.00 6857 5.50 1.10 29C1 19.50 Mallard 1.39 X76M 1.95 4626 1.95 6SA7GT 1.35 30C17 0.40 5763 4.95 C1134 32.00 á180/2M 9.00 PC800 1.10 RK -20A 12.00 68S8 2.50 C1148A 115.00 ECC83 Philips XC24 1.50 4C27 25.00 6SC7 1.50 30C18 1.48 5814A 3.25 G240/2D 9.00 PC900 1.26 111.16 1.50 6BW4 1.50 1.95 XC25 0.50 4C28 25.00 6SG7 1.35 30F5 C1149/1 130.00 6400/1K 14.00 PCC84 0.40 RPL16 12.00 6BW6 5.35 0.95 5829WA 6.50 ECC84 0.50 XFW47 1.50 4CB6 1.95 65H7 1.35 30FL1 1.00 C1150/1 135.00 GC10B 17.50 PCC85 0.54 RPY13 2.50 1.50 5636 5.50 ECC85 0.80 XFW50 1.50 4CX25081.T.T. 66W7 30FL2 1.35 C1534 32.00 GC10D 17.50 PCC88 0.70 RPY43 2.50 66W8 4.00 6SJ7GT 1.20 5678 7.50 ECC86 2.75 XG2-6400 37.50 6SK7 1.35 30FL12 0.95 CCA 2.60 GC10/413 17.50 PCC89 0.70 RPY82 2.50 60X6 0.48 5840 3.50 CC3L 0.90 ECC88 0.85 PCC189 135.00 4CX2508 6SK7GT 1.35 30F113 1.10 GC10/4E 17.50 0.70 RR3-250 15.00 XG5-500 66X7GT 3.50 5842 11.00 CL33 2.00 ECC91 2.00 PCC805 0.70 22.50 EIMAC 49.00 6SL7GT 0.85 30FL14 1.25 GC12/46 17.50 RR3-1250 33.50 XL1-5V 1.50 6826 2.50 5847 10.95 CV Nos Prices ECC180 0.72 PCC806 0.80 4CX250B 6SN7GT 1.35 3011 0.45 ECC189 GD86W 6.00 R5613 45.00 XL628FT 7.50 66Z7 2.95 5879 on request 0.78 PC682 0.80 surplus ex - 6S07 1.35 30115 0.60 8.50 GDT120M 5.00 RS685 54.95 6C4 1.10 D63 1.20 ECC801S 3.50 PCF80 XNP12 2.50 government 6557 1.95 30117 0.60 5886 13.95 GE10 9.00 0.66 RS688 52.15 6C5 1.95 DA41 ECC803S 3.50 XR1-1600A 12.50 1.75 30P4MR 22.50 GN4 6.00 PCF82 0.60 S6F17 5.95 6C6 2.50 6U4GT 1.00 5894 39.50 DA42 17.50 ECC804 0.60 49.50 4CX250B 6U8 1.15 30P12 1.00 5899 4.50 GN10 15.00 PCF84 0.86 S6F33 28.95 6C8G 1.50 ECC2000 12.00 XR1-3200A tested ex- 6U8A 1.50 30P18 060 5963 1.75 DA90 0 4.50 GR1OG 4.00 PCF86 1.20 S11612 38.00 6C11 2.50 ECF80 0.85 PCF87 79.50 equipment 6V6GT 0.85 30P19 1.00 5965 2.25 DA100 125.00 GS1OC 16.50 0.40 S30/26 12.00 6C15 2.50 ECF82 1.15 XR1-6400A 8.00 6X2N 30PL1 2.50 DAF91 0.70 GSIOH 12.00 PCF200 1.80 5104/1K 10.00 6C18 2.50 1.00 6005 1.85 ECF86 1.70 PCF201 99.50 4CX250BM 6X4 1.50 30PL13 0.60 6012 16.00 DAF96 0.65 GS12D 12.00 1.80 5109/1K 15.00 6CA4 0.60 ECF200 1.85 PCF800 Y503 25.00 EIMAC 75.00 6X5GT 1.00 30PL14 1.75 6021 3.65 DC70 1.75 GT1C 14.00 0.40 S130 5.95 6CA7 3.50 ECF202 1.85 PCF801 Y65 8.95 4CX250K 6X5GTV 31JS6A 5.50 6057 2.50 DC90 1.20 GT1C S/S 13.00 1.35 S130P 5.95 6CB5 3.95 1.00 DCX4-1000 ECF801 0.85 PCF802 0.80 Y602 12.00 EIMAC 95.00 6X8A 2.25 33A/158M 6058 3.95 GTE175M 8.00 SC1/800 5.00 6C66 1.95 12.00 ECF804 6.00 PCF805 1.25 YD1100 75.00 4CX125C 125.00 7A6 4.50 19.50 6059 3.75 GTR150W 1.00 SC1/1100 6.00 6CD6GA 4.50 DCX4-5000 ECF805 2.50 PCF806 1.00 YJ1060 265.00 EIMAC 7A7 35A5 4.50 6060 GU20 35.00 SC1/1200 5.00 6CF6 1.50 2.00 2.25 25.00 ECF806 10.25 PCF808 1.25 Y1.1020 29.00 4CX350A 71.50 7AD7 35L6GT 2.00 6062 4.50 GU60 17.50 6CH6 8.95 1.75 DET16 28.50 ECH3 2.60 PCH200 1.50 SC1/1300 6.00 YL1070 115.00 4026 75.00 787 2.50 35W4 0.70 6063 2.00 ECH4 3.00 GXU1 13.50 SC1/2000 9.00 VL1071 135.00 6CL3 3.95 DET18 28.50 GXU3 24.00 PCL82 0.85 4GS7 2.25 7C6 2.50 35Z3 1.85 6064 3.25 DET23 35.00 ECH35 2.15 PCL83 2.50 006000M VL1290 65.00 4GV7 2.25 6CL6 3.25 7E7 2.50 38HE7 4.50 6067 1.95 ECH42 1.00 GXU5OSS 45.00 6CL8A 2.00 DET24 39.00 14.50 PCL85 0.80 277 1.20 4J52 75.00 7AU7 1.50 40KD6 5.50 6072 4.20 ECH81 0.86 SP2 1.50 2302C 12.00 4JC6A 6CM5 1.60 DET25 22.00 GY501 1.20 PCL86 0.85 2.95 7J7 5.50 42 6.95 6080 4.75 DET29 32.00 ECH83 0.78 PCL800 0.80 SP41 5.00 2359 9.00 4X150A 25.00 6CM7 2.95 47 6.00 6080WA 8.50 ECH84 0.69 GY802 1.00 SP42 3.00 7V4 2.50 DF91 0.70 1.00 PCL805 0.90 2505S 15.00 5A/102D 9.50 6CS6 0.75 50A5 1.50 6096 2.85 ECH2000 1.50 GZ30 SP4B 4.95 6CW4 6.50 8138 2.50 DF92 0.60 GZ31 1.00 PD500 3.50 Z520M 4.00 5A152M 9.00 5oC5 0.95 6132 10.00 ECL80 0.60 SS501 35.00 2521M 6CY5 1.00 8810 2.50 DF96 0.65 GZ32 1.00 PD510 3.65 8.00 5A163K 10.00 50CD6G 1.15 6136 2.50 ECL82 0.85 ST71 1.50 2.50 8605 1.95 DF97 1.00 GZ33 4.50 PE1-100 69.00 Z7000 3.00 5A170K 6.25 6CY7 50EH5 1.50 61466 7.95 DH63 1.20 ECL83 2.50 STV280/40 2749 0.90 5A -180M 9.00 6DC6 2.35 8F07 1.95 6157 2.50 ECL84 0.74 GZ34 2.15 PEN25 2.00 50JV6 2.95 DH77 0.90 11.95 Z759 19.85 5A -206K 10.00 6066 10D2 1.25 6158 GZ34MUL3.95 PEN4ODD 2.50 115 52KU 2.00 3.20 DH79 0.56 ECL85 0.89 STV280/80 28000 3.00 5AMB 2.15 6005 3.35 100E7 2.50 ECL86 0.80 G237 4.60 PEN45 3.00 53CG 15.00 6201 6.45 DH149 2.00 19.95 Z803U 18.95 SANG 1.20 6D066 2.50 10F1 ECL805 HAA91 1.00 PEN45DD 3.00 0.75 6205 6.95 DK91 0.90 0.69 SU42 4.95 ZA1000 12.50 5AR4 2.00 10GK6 61SPT 4.50 EF37A 2.00 HABC80 0.90 PEN46 2.00 6DW4 2.15 1.95 6211 2.50 DK92 1.20 TB2.5/300 ZA1001 1.50 5AU4 1.50 10P14 2.50 7581 2.50 EF39 1.10 HBC90 0.75 PFL200 0.95 6EA4 4.95 6267 2.25 DK96 2.50 85.00 ZA1002 1.50 5B8 2.50 10P18 0.78 75C7 2.50 EF41 3.50 HBC91 0.80 PL21 2.50 6EA7 2.50 6350 2.00 DL35 2.50 TB2-300 45.00 ZC1040 8.00 101011 1.00 83 8.50 EF42 3.50 HF93 0.75 PL36 0.95 56.110M 10.00 6EA8 2.50 6360 4.50 DL63 1.00 183/2000 ZM1005 8.00 1011312 0.65 84 3.00 EF50 2.50 HF94 1.50 P138 1.50 3.95 56-254M 14.50 6EB8 1.75 6386 14.50 DL70 2.50 ZM1020 8.95 11E3 85A1 6.50 EF55 4.96 HK90 1.05 PL81 0.72 TB L-2-300 56-255M 19.50 6EM5 2.50 55.00 6545 8.50 DL73 2.50 ZM1021 8.00 58-256M 9.00 85A2 1.50 EF71 1.50 HL2K 3.60 PL81A 0.72 275.00 6EM7 2.50 12A6 3.95 6550A 8.00 DL91 1.50 PL82 0.80 ZM1023 7.95 5B -257M 9.00 12AD6 1.50 90AV 10.00 0192 0.95 EF72 1.20 HL23DD 4.00 TD1-100A ZM1041 14.00 6EU7 1.95 90C1 2.70 6688 6.50 EF73 1.00 HL41 3.50 PL83 0.52 25.00 5B 258M14.50 12AG8 1.50 DL93 1.10 ZM1082 9.00 6EU8 1.75 9oCG 13.50 6870 11.50 EF80 0.55 HL42DD 3.50 PL84 0.78 TD03-10F 5C22 89.50 12AL5 1.00 DL94 2.50 ZM1084 10.00 6EV7 91AG 9.00 6887 9.50 EF83 3.50 HL90 0.70 PL88 1.00 35.00 5R4GB 2.80 2.95 12AT6 0.95 DL96 2.50 ZM1177 9.00 92AG 19.50 68836 9.95 EF85 0.50 H192 1.50 PL95 1.75 TD3-12 4.00 5R4GY 2.80 6EW6 1.50 12AT7 1.15 D1S10 13.50 ZM1202 55.00 92AV 12.50 6973 4.50 EF86 2.25 HL133/DD 3.50 PL302 1.00 514 5.95 6EW7 4.50 12AT7WA 2.50 DLS16 10.00 TDD4 5.50 ZM1263 4.00 95A1 6.50 7025 2.50 EF86 HR2 4.00 P1345 12.50 TP25 5U4G 1.95 6F1 2.00 12AU6 1.50 DM70 1.95 Special 1.50 2M1612 3.00 108C1 1.50 7027A 4.50 Quality 3.15 HY90 1.00 PL500 1.10 TSP4 7.00 5U4G8 2.50 6F5 4.95 12AU7 0.55 DM160 2.75 1A3 4.50 5V4G 15062 6.95 7032 2.00 EF89 0.85 HVR2 3.00 PL504 1.15 TT11 1.50 1.25 6F6G 2.00 12AV6 0.80 DY51 1.50 PL508 1.75 1AC6 1.20 5V3GT 1.85 12AX4GT 150C2 1.50 7059 2.50 EF91 1.60 JP9-7A 60.00 TT15 34.95 6F7 5.50 1.00 DY86/87 0.85 PL509 4.85 183GT 1.95 5Z4GT 0.85 12AX7 0.65 15oC4 2.15 7167 3.95 DY802 0.72 EF92 2.15 K3118 85.00 TT21 34.95 6F12 1.50 155UG 25.00 PL519 4.95 1822 10.00 6/3012 0.70 12AX7WA 2.50 7189. 2.35 EF93 0.95 KR6/3 46.00 TT22 34.95 6F13 3.00 18567 1.50 E55L 42.00 EF94 0.95 PL802 5.95 1824 14.95 6A/203K 9.00 12AY7 3.95 7193 7.50 E80CC 9.95 KTBC 7.00 TT100 57.00 1B35A 6F14 1.00 274A 15.00 EF95 1.50 P1802T 3.50 29.50 6A7 4.95 12AZ7A 1.95 7199 4.95 E80CF 11.00 KT33C 3.50 1BC2A 2.50 6F17 2.75 307 5.00 EF97 0.90 KT36 2.00 PL820 2.95 TTR-31 MR 6A8G 1.50 1284A 3.50 7233 7.95 E80F 13.50 PL5557 IC1 6F21 2.50 328A 15.00 EF98 0.90 KT44 4.00 29.50 65.00 2.50 6A88 0.66 12BA6 1.50 7239 17.50 12.00 6F22 0.70 388A 17.50 E81L EF183 0.65 KT45 4.00 PY32 0.60 TY2-125A 85.00 1C5GT 2.50 6AC7 2.00 128E6 1.95 7247 2.95 E82CC 3.50 PY33 0.50 6F23 0.60 12BH7A 425A5 8.00 EF184 0.65 KT61 4.00 TY4-400 70.00 105 2.50 6AF4A 2.50 2.50 7360 8.95 E83CC 3.50 6F24 1.25 431 U 2.00 EF730 1.80 KT63 2.00 PY81 0.70 TY8--600W 1FD1 2.50 6AF9 4.15 12016 1.75 7462 15.00 683F 5.50 PY82 6F25 1.25 12BY7A 5728 35.00 EF731 3.50 KT66 OSRAM 0.70 385.00 1G3GT 2.50 6AG5 1.50 2.75 E86C 9.50 PV83 0.70 1K3GT 6F28 1.25 705A 6.00 7475 5.06 EF732 3.50 10.50 TYS2/250 2.50 SAG7 1.95 6F32 1.25 12626 4.95 7486 E88C 7.95 PY88 0.85 708A 8.00 75.00 EF800 11.00 375.00 114 0.60 6AH6 2.50 6F33 17.00 12CA5 1.95 E88CC 3.50 KT66 USA 6.90 PY500A 1.95 715A 8.00 7551 5.45 EF805S 13.50 KT66 GEC 14.95 U18-20 2.75 1 L6 1.50 6AJ4 2.00 12CX6 1.20 E9OCC 7.95 PY800 0.79 6FG5 1.95 715C 45.00 7558 9.45 EF806S 14.50 U19 11.95 1LA6 1.00 6AJ7 2.00 120068 3.50 E90F 7.9! KT77 Gold Lion PY801 0.79 6G6G 5.50 725A 275.00 7586 11.00 EF812 0.65 9.50 U24 2.00 1N2 4.50 6AK5 1.50 12DW4A 803 14.95 E91H 4.50 OB3-300 30.50 6GH8A 0.80 3.50 7587 28.95 EFL200 1.50 KT81 7.00 U25 0.90 iN5GT 2.50 6AK6 2.00 E92CC 3.95 0E03-10 3.50 6GK5 1.50 12DW7 2.50 805 39.00 7591A 4.95 EH90 0.72 KT88 USA 9.00 U26 0.90 1P28 25.00 6AL5 0.80 807 1.60 E99F 6.99 61(90 0.72 0E08-200 6AM4 3.25 6GK6 1.95 12E1 17.95 7609 47.00 KT88 Gold Lion U37 9.00 1S2 810 45.00 E130L 19.95 EL32 0.95 145.00 0.55 6AM5 6GS7 2.15 12E14 28.00 7733 5.50 16.95 U41 6.95 1S5 0.70 8.00 811A 12.95 6180CC 6.50 EL33 4.00 0F40 65.00 6AM6 1.50 6GV7 2.50 12GN7 3.95 7788 18.50 KT88 GEC 13.95 U50 2.00 1T4 0.70 813 18.50 E182CC 9.00 EL34 2.25 OP25 1.00 U82 3.00 6AN5 2.65 6GW6 2.50 12HG7 4.50 7868 3.95 KT67 9.00 1U5 1.00 12HG7A 4 813USA 45.00 6180F 6.50 EL34 Mallard 00E03-12 6.50 U191 0.70 6AN8A 2.65 6H1 9.50 S 8012 15.00 8.50 K1W61 2.50 1X2B 1.40 E186F 3.95 00E03-20 27.00 U192 1.00 8042 45.00 E188CC 7.50 KTW62 2.50 Q0V02-6 19.50 1Z2 8.95 6134 Philips4.50 KTW63 2.00 U193 0.65 8102 3.95 E1T 15.00 00V03-10 5.50 287 1.50 EL36 1.50 KTZ63 2.50 U251 1.00 8106 2.95 E280F 19.50 00V03-10 EL37 9.00 163 1.50 U801 0.75 2822 69.50 8136 1.00 6283CC 10.00 Mallard 9.50 CALLERS WELCOME EL38 4.75 L102/2K 8.95 UABC80 0.65 2C21 1.00 8156 10.95 6288CC 13.50 QQV03-20 EL41 3.50 L120/2K 12.00 UAF42 1.00 2C39A 23.50 8245 107.50 E810F 18.50 18.50 2C39BA 39.50 * ENTRANCE ON A227 EL42 2.00 LB7-20 95.00 UBF80 0.60 8298A 6.50 EBBCC Siemans 0QV03-208 2C40 37.00 EL81 6.95 LS98 6.95 UBC41 2.95 50 YDS SOUTH OF MEOPHAM GREEN 8417 5.95 Special 5.95 32.00 UBC81 1.50 2C40A 55.00 EL82 0.58 M502A 60.00 00V06 -40A 9001 1.50 61148 1.00 EL83 5.95 85.00 UBF89 0.80 2C42 29.50 9006 0.90 51524 6.95 19.50 UBL21 1.75 2C51 0.75 CAR PARKING AVAILABLE EL84 0.75 M537A 60.00 00V07-50 18042 10.00 EA50 1.00 EL85 4.50 M5143 155.00 UC92 1.20 2C53 32.00 Open Mon-Thurs 9am-5.30pm Fridays 9am-5.00pm 18045 10.00 EA76 1.95 63.50 UCC84 0.70 2CY5 1.50 EL86 0.85 M8079 6.00 00203-20 EA79 1.95 EL90 1.50 M8082 7.50 UCC85 0.60 2021 0.95 24 HOUR 42.50 2021w 2.50 * ANSWERPHONE SERVICE EABC80 0.70 EL91 6.00 M8083 3.25 UCF80 1.00 ACCESS AND * 6AC91 2.50 EL95 0.70 M8091 7.50 Q0Z06-40A UCH21 1.20 2E26 7.95 BARCLAYCARD ORDERS WELCOME TNERMISTORS 45.25 2J42 MANY OTHER ITEMS EAF42 1.20 61153 12.15 M8096 3.00 UCH41 2.50 93.00 * AVAILABLE * VA1040 023 EAF801 3.60 EL183E 3.50 M8098 5.50 OS72/20 1.50 UCH42 2.50 2K25 24.95 0S75/40 3.00 VA1056S 0.23 E834 1.50 EL18P 3.50 M8099 5.00 UCH81 0.65 2K25 Raytheon UK ORDERS P&P 50p PLEASE ADD V.A.T. AT 15% VA1104 0.70 6841 3.95 M8100 5.50 0S92/10 5.00 EL360 6.75 4.85 UCL82 1.75 75.00 VA8650 0.45 6691 0.60 EL500 1.40 M8136 7.00 OS95/10 UF85 EXPORT ORDERS WELCOME. VA1097 0.25 68C33 2.50 61504 1.40 M8137 5.50 QS108/45 4.00 1.20 CARRIAGE/POST AT COST

CIRCLE 20 FOR I l'RTHER DETAILS. ELECTRONICS & WIRELESS WORLD DECEMBER 1984 -t9

www.americanradiohistory.com NEW DISCO ELECTRONIC CENTRE SATELLITE TV RECEIVING EQUIPMENT U.K. and EXPORT RETURN OF POST MAIL ORDER

BAKER LOUDSPEAKERS Post E2 each. MODEL INCHES OHMS WATTS TYPE PRICE * BAKER * Disco/Group 10 816 50 PA £18 Midrange 10 8 100 MID E25 GROUP P.A. DISCO Major 12 4616 30 HIFI f16 Superb 12 8-16 30 HI-FI E26 12 er. Woofer 8 BO HI-FI E25 Auditorium 15 8-16 60 Bass £37 . Disco/Group 12 4-8.16 45 PA f16 1 t 1 1

Disco/Group 12 4-8-16 75 . PA £20 0 0 0 0 rP Disco/Group 12 8-16 100 PA £26 Disco/Group 15 8-16 100 PA £35 REPAIR service to most Baker loudspeakers. 50% List Price SPEAKER COVERING. Samples S.A.E. CABINET WADDING 18in wide 35p h. PA.150 Watt MICROPHONE VOCAL and SPEAKER CABINET Designs manual E3.50 GROUP AMPLIFIER £129 4 channel mixing, 8 inputs, dual impedance, 50K-600 MOTOROLA PIE2O ELECTRIC HORN TWEETER, ohm, volume, treble, bass. Presence controls on 3iin square £6. 71x34in. Flared Horn £10 each channel. Master volume control, echo, send 100 watts. No cross over required. 4-8-16 ohms, return socket. Slave sockets. Post £3. HORN BOXES, complete 200 watt £30. 150Watt MIXER AMPLIFIER 4 Inputs £99 300 watt £35. Black vinyl covered with handle Discotheque, Vocal, Public Address. Speaker outlets and lin jack sockets Post £4. for 4, 8 or 16 ohms. Four inputs, 20 mv, 50K ohm. Individual volume conrols 'Four channel" mixing. CROSSOVERS. TWO-WAY 3000 40 watt £4. Slave output 16' x 8' x 53'. Wt - 1415: Master 60W £5. 100W £6. volume control. 240V A.C. Post £2. THREE-WAY 950 cps/3000 cps. 40 watt rating. £4. 100 Volt Line Model, 150 watt £114. 60 watt £6. 100W £10. MONO SLAVE. 150 watt £80. LOUDSPEAKER BARGAINS. Please enquire, many Baker Stereo Slave 150 + 150 watt per channel others in stock. 1300 watt mont 'Heavy Duty Model £125. Post £4. 4 ohm, 5in, 7X4in, £2.50; 63 in. 8X 5in, £3; 8in, £3.50. 61 in 20W, £7.50. Bin 40 watt £7.50. BAKER MOBILE PA AMPLIFIER. All transistor, 60 8 ohm, 28in, 3in, £2; 5x 3in, 6x4in, 7x4in, 5in, £2.50; watt RMS, 12v DC & 240v AC, 4 inputs 50k Aux + 2 3in, 10W £4.8X5in, £3; 8in, £4.50; 10in, £5; 12in, £6; mics + 1 phono loudspeaker. Output Bin 25W £6.50; 60W £13.50. 12in 40 watt £10. 4-8-15 ohms + 100 volt line. £89 Post £2 15 ohm, 2i in, 3iin, 5X 3in, 6X4in, £2.50. 6; in 10W £5. 60 WATT VALVE AMPLIFIER £69 carr. £3 Bin £4. 10in f 7. 25 ohm, 3in. £2; 5X3in, 6x4in 7x4in. £2.50. Inputs 3 mike - 1 aux. -1 phono + 100 line. EMI 131 XAin Bass & Tweeter 4 or 8 ohm 10 watt £8 Outputs 4-8-16 ohm volt

WATERPROOF HORNS B ohms, 25 watt 10in. £22. 30 watt 8X43ìn. £23. 40 watt 12in. £33. 20 watts 12ín. 1.9M, 2.5M and 5M Dishes. Receivers, FAMOUS LOUDSPEAKERS plus 100 volt line £38. Post £2. MAKE MOOD. SIZE WATTS OHMS PRICE POST Downconverters, Low Noise Amplifiers, Feed Horns AUDAX WOOFER 53ín 25 £10.50 E1 BAKER PORTABLE DISCO 150 watt. Twin console + GOOOMANS HIFAX 7-x4, 100 £30 O amplifier mike and headphones + twin speakers available. 000098NS HB 8in 60 £13.50 LI £360. Carr. £30. Console only £145 Carr £10 WHARFEDALE WOOFER 8in 30 £9,50 Q PA CABINET SPEAKERS. Complete. 8 ohm 60 watt /16 f21 E2 Complete systems installed anywhere in the world. CELESTION DISCO 10m 50 170115x9in. £27. Post £4. 4 or 8 or 16 ohm 75 wan GOODMANS HPG lie 120 /15 £30. O 20X 15x9in. £52. 90 watt 32x 15 x 11 in. £73. 150 watt HPD 120 /15 A 000090NS 12e £30. O E82. Carr. £10 Black vinyl covered with handles. full report on reception feasibilities at any location GOODMANS HP 15e 250 £72 £1 is GOODMANS HPD 18in 230 £H £4 MAINS TRANSFORMERS Post available - price £25.00. Many others please telephone your enquiry. 250-0-250V Boma. 8-3v.2a £6.00 £2 250-0-250v 80mA, 6.3V 3.5A, 6.3V IA £7.00 £2 Please state Longitude and Latitude. RCS STEREO PRE-AMP KIT. Inputs for high, medium 350-0-350V 250mA, 6.3V 6A CT £12.00 £2 or low imp volume control and PC Board. Can be 220V 25ma 6V lamp £3.00 £1 ganged for multi-channel£3.50 220V 45ma 6V 2 Amp £4.00 £1 250V 60mA, 6V 2A £5.00 £1 For further details contact: Harrison Electronics, 22 Milton SINGLE PLAY DECKS. 240v AC Step -Down 240V to 115V 150w £9. 250W £12. Post £2. 500W £14 post £2. Road, Westcliff-on-Sea, Essex SSO 7JX. Telephone: Make Modal Cartridge Price GARRARD 6200 Ceramic £22 GENERAL PURPOSE LOW VOLTAGE Southend (0702) 332338. BSA P182 Ceramic f26 Tapped outputs available Price Post BSR P232 Magnetic £28 2 amp, 3, 4, 5, 6,8,9, 10,12, 15, 18,15 and 30V £6.00 E2 BSR P207 Ceramic E20 1 amp. 6,8,10.12,16, 18, 20, 24, 30, 36,40, 48,60 £6.00 E2 CIRCLE 13 FOR FURTHER DE'T'AILS. BSR 12 DC P257 Ceramic £24 2 amp. 6, 8, 10, 12,16,18, 20, 24, 30.36, 40,48,60 £10.50 f2 5-8-10-76V.ì amp £2.50 £1 0.842V.5amp £5.00 E1 AUTOCHANGERS 240 VOLT AC 6V.; amp £2.00 £1 15-0-15V. 1 amp £4.00 f1 6-06V. 1i amp £3.50 f1 15-0-15V.2 amp £5.00 £1 BSR Deluxe Ceramic £20 A compact mains -powered unit with one 9V. 400ma £1.50 £1 20V.1 amp 14.00 ft BSR Deluxe Magnetic £26 balanced input and ten a.c. and d.c. iso- GARRARD Deluxe Ceramic £22 W. 3 amp £4.00 £1 20-0-20V.1 amp £3.50 £ 1 10 OUTLE lated floating line outputs. 9.0-9V.50ma £1.50 £1 012-27V.1amp £4.00 £1 R.F. breakthrough speci- £3.50 £1 20-40-600.1 amp £3.50 £2 *Exemplary DECCA TEAK VENEERED PLINTH 9-0-9V.1 amp fications giving trouble -free operation 10.0-10V. 2 amp £4.00 £1 250-250.2 amp fá.50 £1 Superior finish with space and panel for small DISTRIBUTION in close proximity to radio telephones 10-30-400.2 amp £5.50 £1 24V. 5amp Twice £12.00 f2 amplifier and most record decks. and links 12V. 100ma £1.50 £1 300.1; amp £5.00 f1 Board cut for BSR or Garrard 185in x 141 in. 014in. £5 *Excellent figures for noise, THD, static 12V. 750 ma £2.50 £1 30V. 5 amp an AMPLIFIER 3 Black/chrome facia trim. Post £1 and dynamic IMD 12V.3 amp £4.50 £1 17-0-172a £4.50 £2 Any desired number of outlets may be 12v,5amp £5.00 £1 12-012v lamp £3.50 £1 * TINTED PLASTIC COVERS for Decks, Music Centres, provided at microphone level to suit 12-O.12V.2 amp £4.50 £1 .35V.2 amp £4.00 £1 f5 each. Post £1. certain video and audio recorders 171 x 134 x 31in. 181 x 123 x 3in. LOW VOLTAGE ELECTROLYTICS used at press conferences 17; x 95 x 3iin. 141 x 12i x 21 in. 500mF 12V p P *Meets IEC65-2, BS415 safety and 163 x15 x 43in. 164 x 13 x 4in. 10 00mF 12V 20p; 25V 35p; 50V 50p; 100V £1..20 I.B.A. 'signal path' requirements 17 x 121 x 33in. 143 x 134 x 22in. 2200/63v £1.30 Also as a kit parts less 221 x 131 x 3in. 21 x 13d x 4i1n. 2000mF 30V 42p; 40V 60p; 100V £1.40; available of the case and all XLR for 21; x 14; x 23in. 301 x 135 x 31in. 1500mF 100V £1.20. connectors one or x x 2500mF 50V 70p. 3000mF 50V 65p; 4700mF 40V £1. ten outlets. 231 14 31ín. Broadcast Monitor Receiver 150kHz- CAPACITORS WIRE END High Voltage. 30MHz Stereo Disc Ampler 3 and BULK TAPE * 4* THE "INSTANT" .001..002, .003, .005, .01_02_03_05.03, .05 mfd 400V 10p. Coil Post 95p Moving Preamplifier * Illuminated ERASER £11.50 .IMF 400V 14p. 800V. 20p. 100V 30p PPM Boxes PPM Drive Boards and Hand-held. Compact unit. * .22MF 350V 12p. 600V 26.1500V 30p. 1750V 60p. Ernest Turner Movements * Stabilizer Suitable for cassettes and all .47MF 150V 10p. 400V 25p. 630V Will 30p. and Frequency Shifter Boards * Peak sizes of tape reels. AC 240V. Deviation Meter Programme De- also demagnetise tools. HIGH VOLTAGE ELECTROLYTICS * and 2/5000 viation Chart Recorders PPM5 Tape Head Demagnetiser £5. 45p 32+32+16/3500 90p 8+16/4500 95p * 20 pin 16/450V 50p 220/4000 C1 4.7/5000 50p DLL hybrid * Stereo Microphone Ampli- PROJECT CASES 20/5000 75p 150+200/2750 50p 32+32/350V 85p fier. vinyl covered top and sides 32/350V 45p 32+32+32/450V11.50 20+20/3500 75p Black SURREY ELECTRONICS 6X4x13m £3.60 8X5X2in E4. 32/500V 95p 8+8/4500 85p 50+50/3000 50p LIMBED The Forge, Lucks Green 9x5x23in £4.80 11 016x3 £5.50 17/350V 75p 8+8/5000 £1 32+32/5000 £2 113x6015 £9 13x80143 £11. Crenleigh, Surrey GU6 7BG ALUMINIUM PANELS. 6X4 55p; Bx690p; 14x3 £8.50 post 50p MINI -MULTI TESTER. Tel 0483 275997 90p; 10X7£1.15; 12x811.30; 16x6£.30; 14x9 moving coil4000 o.p.v. 11 instant £1.75; 12x12£1.80; 16x10£2.10; ranges measure: DC volts 5, 25, 250, ALUMINIUM BOXES. 4014X13 £1.20; 4x23x2 £1.20; 500. AC volts 10, 50, 500, 1000. 3012x1 £1.20; 6014x2£1.90; 7015x23 £2,90; 8x6013 0-254a; DC 0-250ma. DC Resistance £3; 10X7X313.60; 12X5 x3£3.60; 12x8013£4.30; 0 to 600K ohms. 9014x4 £3: 6x401 3 £2.20; 4014x23 £1.60. De-Luxe Range Doubler Meter, RACKMOUNT 50,000 o.p.w. 7 x 5 x 2in. Resistance CASES meg in POTENTIOMETERS 5k/2meg LOG or LIN. LIS 50p. 20 5 ranges. Current 50pA to 10A Volts 0.25/1000v DC. DP 90p. Stereo L/S £1.10. DP £1.30. 10v/1000v AC. £25 post £1 DISCO MIXER 240V, 4 channels. 2 magnetic, 2 PANEL METERS 50µa, 500pa, 1 ma, 5ma, 50ma, ceramic/tape, 1 mono mic channel, twin v.u. meters, 100ma, 500ma, 1 headphones monitor outlet, slider conrols, panel or amp, 2 amp, 5 amp, 25 volt, VU 5901 53 x 34mm. Stereo VU X41 x25mm desk mounting, .grained aluminium facia. Tape 82 £5.50 output facility £51. Post £1. RCS SOUND TO LIGHT CONTROLLER KIT £19 Printed circuit. Cabinet. 3 channels. 1,000 watts each. DELUXE STEREO DISCO MIXER/EQUALISER as Will operate from Hi-Fi or Disco. Post £1. above but L.E.D. V.U. displays 5 band graphic Ready Built Deluxe 4 Channel 4,000 watt with chaser equaliser, left/right fader, switchable inputs for + speed + programme controls £69. Post £2. New Model Mkll with special 16 programmes: phone/line, mike/line. Recording Output. £124 19"Self Assembly Rack Mounting Case with lift off Covers. Front Panel 10 gauge, 4 channel 4,000 watt £89 post £2 Brushed Anodised Aluminium, Case 18 gauge, Plated Steel Removeable Headphone Monitor, Mike Talkover Switch Pair of 4 channel Light Boxes with Rear In As above but 7 Band Graphic £136. post £2 Complete with 8 coloured bulbs. The pair clip & Side Panels. 1U & 2U Types, a Subplate Chassis is Mounted to Bottom Cover. together for easy transport £70. Carr. £4. In 3U Type the Subplate is located on two Rails Mounted Between The Side Plates. ELECTRONIC REVERB UNIT inputs for MIC + LINE BATTERY ELIMINATOR Mains to 9 volt D.C. 400MA. All slide controls 9v Battery operated E34 Post £1. Stabilised, safety cutout, 5x 31 x23 in. £1. £5. Post 1 U (1'/4) height, 230m depth £27.00 2U (31/2) height, 308m depth £32.00 RADIO COMPONENT SPECIALISTS 3U (51/4) height, 230m depth £39.00 Width Behind Front Panel 437m Dept 1, 337, WHITEHORSE ROAD, CROYDON (All Types). All Prices Postage SURREY, U.K. TEL: 01-6841665 'nclude & V.A.T. Cheques, Postal Orders Payable to: - /ACCESS Post 65p Minimum. Callers Welcome VISA J. D. R. Sheetmetal, 131 Grenfell Road, Maidenhead, Full Lists 34p. Same day despatch. Closed Wed. Berks. SL6 1EX. Maidenhead 29450. CIRCLE 6 FOR FURTHER DETAILS. CIRCLE 41 FOR FURTHER DE'T'AILS,

5I ) ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com EPROM PROGRAMMER Intelligent eprom programmer

Having its own processor, this intelligent programmer can quickly copy eproms up to by J.H. Adams, the 27512 and list eprom data on a serial M.Sc. printer - under computer control it programs one -chip microcomputers. Part two discusses computer control software and construction.

My control program for SC84* is that the computer might have sum of data read from the slave written in assembly language but waiting in its transmit buffer socket, and the 16 -bit address of a program written in a high-level when the two are connected. the last programmed location language could be used at the At the end of the transfer, the plus one. By manipulating these expense of speed. The SC84 pro- program must examine eight figures, and a check sum of the gram uses CP/M-compatible sys- bytes returned by the program- data file where appropriate, the tem calls so it should be possible mer. These bytes consist of a 24 - program should be able to indic- to adapt it for other CP/M compu- bit check sum of data read from ate to the user whether pro- ters. The only 'non-standard' the master socket, a 24 -bit check gramming was successful (check requirement is that the program sums equal) or if not, what went needs to know the serial -port sta- wrong. Indicating what went tus, i.e., whether it is ready to be Send 0A616 wrong is most easily done by dis- sent a character or whether there playing the programming address is a character in its receive buffer. and the exclusive -or of the two Flow diagram of Software for the eprom program- Send type differing check sums, which forms communication between the mer is in an eprom provided with a map of the bits that disagreed eprom programmer and a the kit. The SC84 control pro- during verification. The check computer through the serial gram is available separately on Send commend sums should be displayed as a link. disc (details later). Computer software for rem- otely controlling the eprom pro- o grammer needs to display eprom types and programming com- mands available, and to input and Yes validate the user's selection If the operation involves a disc file, the program has to receive and valid- ate the file identification. It must also react if a file for passing data to the programmer doesn't exist, or a file for receiving data from the programmer already exists. Store byte When the eprom type has been established, the program must Send next byte draw the length of the eprom from o a table for use during file transfer. Communication between the computer and programmer is out- lined in the flow diagram. The Yes A616 byte sent before each opera- tion is an arbitrary code signalling the start of the operation. It is used so that the programmer is not put off by any odd character Read and store 8 status bytes *SC84 was described in the May, June, July, September and October issues of E&WW ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com EPROM PROGRAMMER

source of information after a ment for the program. Other containing Intel hexadecimal data between computers much `sum -check only' is almost command essential elements are code (a standard form for assem- easier. Actual data in an Intel ended. some form of progress indicator bler or linker output files) and hex. file consists of lines or require- These are minimum and a routine that recognizes files translates it into hexadicimal `records' of ascii characters each form before it is sent to the pro- consisting of a colon, the count of Fig.1. Displays presented by John Adams' SC84 software for grammer. My program for the the number of data bytes in, the controlling the eprom programmer. The first of these, (a), SC84 includes these features and line, a null byte, the data bytes, a shows a sum check of two erased 2716 eproms. An attempt to more. check sum of the characters in read data from a 2732 in the slave socket into a disc file in Typical screen displays are the line followed by carriage - which the file EPROM.COM already exists is shown at (b). shown in Fig. 1(a -d) You are first return and line -feed characters. Screen (c) is a simulation of a bad -programming error prompted for the eprom type and The last record in the file has a produced by attempting to copy a 2732 to an empty slave then for the operation required. zero data count and holds the pro- socket and (d) shows a successful attempt reading an eprom's In each case, only a single letter is gram start address as its starting content into a disc file. entered. If commands A or B are address. chosen, they execute immedi- SC 84 Eprom Programmer Control ately. Any other command Construction Program Version 1.00 results in a prompt for a file name to be used for the destination A - 2716 B - 2732 C - 2732A D - 2764 or These notes assume that you are E - 2764A F - 27128 G - 27128A H - 27256 source of data. Invalid file names using the kit and p.c.bs men- - 27512 J - 27513 K - 8741/8 L - 8749 of more than eight characters or tioned at the end of this article. invalid file types of more than The Enter your EPROM choice, A to L, now...A main board has components three characters are rejected. mounted on both sides. All of the A - ABORT session B - SUMCHECK only The file is searched for on the components on side two of the C - Read MASTER to COMPUTER D - Read SLAVE to COMPUTER disc and extra prompting occurs, board, i.e. all but the leds, push E - COPY MASTER TO SLAVE F - PROGRAM SLAVE Fig. 1(b), if the destination file from COMPUTER buttons and zero -insertion -force already exists (commands C to E) (zif) sockets, should be mounted Enter your COMMAND choice, A to F, now...B or cannot be found (command F). and soldered first. Then mount SUMCHECK of MASTER EPROM is 07F800 Once a correct file specification the zif sockets by setting the lever SUMCHECK of SLAVE EPROM is 07F800 has been entered and initiated, to its lock position and working the message `programming A - 2716 B - 2732 C - 2732A D - 2764 now' the socket carefully into the relat- E - 2764A F - 27128 G - 27128A H - 27256 appears on the screen and prog- ively tight -fitting holes on the I - 27512 J - 27513 K - 8741/8 L - 8749 ressively tuns into reverse video p.c.b. as programming proceeds. Previ- Enter your EPROM choice, A to L, now...B Push buttons and leds should ously entered information about be mounted next, but not yet sol- A - ABORT session B - SUMCHECK only the eprom type is used by the soft- dered. Make sure that the leds are C - Read MASTER to COMPUTER D - Read SLAVE to COMPUTER ware to work out how to scale the right way round, with their E - COPY MASTER TO SLAVE F - PROGRAM SLAVE the progress of this operation so from COMPUTER anodes connected to the adjacent that there are always the same resistor. Fit the p.c.b. to the top Enter your COMMAND choice, A to F, now...D number of changes. The rate of panel of the case using the M3 change varies faithfully in terms nuts, screws and spacers. With ENTER the name of the DATA FILE ... EPROM.COM of bytes programmed as the pro- the board centralized against the gramming algorithms skip or This FILE does ALREADY EXISTS. Do you want toA - INPUT a NEW top panel and the nuts tightened, FILE NAME, or, shorten programming time. adjust the switches so that they B - OVER -WRITE the FILE Programming ends when all are square within their cut-outs Enter your choice, A or B, now... locations are programmed or an before soldering them in. Next, error occurs. After A - 2716 B - 2732 C - 2732A D - 2764 successful align the leds so that they stand E - 2764A F - 27128 G - 27128A H - 27256 programming, check sums of the vetically and square in their panel - 27512 J - 27513 K - 8741/8 L - 8749 eprom and disc file are displayed. holes and solder them. The One of these is derived by the 6MHz crystal Enter your EPROM choice, A to L, now...B stand upright and computer, the other by the pro- can be swathed in silicone com- A - ABORT session B - SUMCHECK only grammer, so they provide addi- pound to strengthen its mounting C - Read MASTER to COMPUTER D - Read SLAVE to COMPUTER tional cross-checking of the pro- if required. E - COPY MASTER TO SLAVE F - PROGRAM SLAVE gramming. If an from COMPUTER error occurs, The cable linking the main both check sums are displayed board and power -supply p.c.b. Enter your COMMAND choice, A to F, now...E together with an error pattern should be between 16 and 17cm of SUMCHECK of MASTER EPROM is 0000E9 consisting of a hexadecimal byte the ribbon cable stripped of the SUMCHECK of SLAVE EPROM is 0000FF in which logic ones represent ERROR Pattern is 16 black wire. The 9 -way plug PROGRAMMING ADDRESS is 0000 faulty bit positions in the eprom should be fitted to the main p. c. b. location, and the address location and a 9 -way connector fitted at A - 2716 B - 2732 C - 2732A D - 2764 of the error. Status leds on the one end of the cable with the gap E 2764A F 27128 G 27128A - - - H - 27256 programmer are set to reflect the in the connector between the vio- I - 27512 J - 27513 K - 8741/8 L - 8749 result of the programming. let and grey wires. Solder the Enter your EPROM choice, A to L, now...B An extra option is available cable at the power -supply p.c.b. when using command F. If the file with the wires in the same order A ABORT session B - - SUMCHECK only specification given as the data as at the connector. To link C - Read MASTER to COMPUTER D Read SLAVE to COMPUTER the - source is a .HEX E - COPY MASTER TO SLAVE F - PROGRAM SLAVE type, the file is transformer and power -supply from COMPUTER assumed to contain code in Intel board, a short length of ribbon hex. form and is compiled accor- cable is soldered to the transfor- Enter your COMMAND choice, A to F, now...0 dingly, with the starting address mer at one end and fitted to a five - ENTER the name of the DATA FILE... B: F8086. OBJ assumed to be the first location in way connector with pins two and SUMCHECK of MASTER EPROM is 078200 the eprom. Data in the file is all four removed at the other. SUMCHECK of DISC FILE is 078200 ascii which makes the transfer of A 20cm length of 5 -way ribbon

ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com cable with a 5 -way connector at board. Your voltmeter must be one end and soldered to a 25 -way accurate to 250mV and cover the female D -type connector at the range 0 to 30V. Check that the 5V other forms the serial data con- line is correct and that the +12 nection, Fig 2. The D -type con- and -12V rails are within 2V of nector conforms to the standard their nominal values. Check that `output-to -peripheral' configura- VPP is zero then temporarily link tion for an RS232 port and can be PSU ON to +5V and check that connected to a printer using a VPP rises to somewhere between tor between VP and OV (e.g. in Fig. 2. The serial interface D direct pin -for -pin printer cable. +12 and 30V and falls back to parallel with C7) and connect the connector on the programmer For communications with a com- zero when the link is removed. voltmeter across it. Switch the used for computer connection puter, a special cable will be When the supply is operating programmer on, press the LIST or printer driving, left. needed to suit the computer's as described switch off, connect button, and adjust R109 on the power supply board to set VPP to Fig. 3. Cable connections for socket. For SC84, the serial port the programmer board and switch connecting the programmer of which is wired exactly as the back on again. The two leds indi- 25V. Switch the programmer off, to SC84. These crossovers programmer's, this consists of a cating 2716 and the OK led are required as the computer cable terminated with male con- should light. If not, check the pause, then switch it back on again. Select 2732A programm- and programmer have the nectors and with its data and supply rails, wiring of the leds same pin numbering. hand -shake lines crossed over as (especially if one or two of those ing using the UP button then press LIST. Adjust R109 on the supply Normally, connection to a shown in Fig. 3. expected to light do light) and printer wil be pin for pin. A 2732 eprom is supplied with general construction. board to set VPP to 21V. Switch the programmer control pro- Next press the UP button to test off, pause then switch on again, gram; for this device LK1 (the all of the eprom indicator leds. select 27256 press list, and long one) should be made. The With the indicator again set to adjust R110 on the power supply to other link is allows a 2716 to be 2716, press and release the PRO- set VPP to +12.5V. Switch off and used. GRAM button. A relay should remove the 680Q resistor. Note Both the 8035 and 8243 are operate and the OK led should go that R1oa affects all voltages and so available in cmos as the 80C35 out and the PROGRAM led light the programming voltages must Main circuit correction. The and 82C43 and a version of the for around 1 to 2s. If this happens be set up in this order. circuit around pin 1 of the programmer has been con- press and release the UP button, To test the listing function con- master and slave sockets structed using them. There are checking that the indicator reads nect a printer and, if it is set for shown last month is revised no problems in doing so as the 2732. Press the PROGRAM but- one of the available data rates as shown. cmos versions have the same cur- ton. One relay should release and Old circuit.... should be: rent sinking capabilities and another activate followed by Stave socket Slave socket interface levels as equivalent about 4s of attempted programm- pin 1 pin 1 nmos parts. Using cmos devices ing. Master saves power, but the three cmos To set the progamming V sup- socket i.cs cost two to three times more ply, switch the programmer off RL2 pin 1 than three equivalent nmos then on again. Insert a 120Q Master gRL2 socket devices which together can resistor in pins 14 and 28 of the VPP - pin 1 cost less than just one of the 28 - slave socket, lock the socket, and pin zero -insertion -force sockets. measure the voltage on pen 28. It IC9 pin 16 1C9 pin 16 should be between 4.75V and

Setting up 5.25V. Short of the base of Tr, to other than 9600 baud, use the UP Fig . 4. Multi -rail power its emitter and adjust VR1 on the or DOWN buttons to move the supply for the intelligent After carefully checking the con- main board until the reading is pointer to the desired rate and eprom programmer. struction, connect just the trans- 6V. Remove the short and the press the LIST button to select Programming voltage VPP is former to the power supply and resistor. that rate. Move the pointer to determined by the processor test this part of the circuit, Fig. 4, To set the programming vol- 2716 and press the LIST button, through input/output expander before connecting the main tages, connect a 1W, 680Q resis- whereupon the printer should EXPO pins 2, 3 and 4.

C101 D106 Tr101 0 IC102 Vpp BD 136 7812 12 VA 220N 1N4001 50V R101 R104 9V 0101-D104 ^ 0105Z 1N4001 4. C106 47k 4n7 2k2 50V 14 OVT R109 Mains IC 01 Tr104 supply 780 5 2N3904 10k R102 Rice R105 6 R110 C105 22k 1k PSU 2 9V C104 T> 500 6k8 R106 7 C102 220 T00n2m2 R103 PSU 1 SOV 60 Tr103 k8 16V 2N3904 R107 8 Tr102 PSU ON 2N3904* 6k8

OV C103 T220» 16V 12V

+12V

2 +5V

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 53

www.americanradiohistory.com EPROM PROGRAMMER

nature of most of the signal con- be carried out by reading the mas- C203 nections to the programming ter device into a disc file and then

C201 100nI 'ceramic socket. One example of an programming other devices using is 4p7 40 unusual programming task to the file. 39 program microcomputers with The address for the 8748 pro- T 22p j3MHz 3 38 built-in eprom. gramming operation is not gener- C202 i 4 37 Several such microcomputers ated by the programmer's ;6 - including the one used in this CD4040 as it is for eproms, but 35 6 programmer are available with from a count kept in one of the 34 - 40 -pin 8 33 -Not connected built-in eprom. The idea of such a 8035 ram locations. This counter zif socket 32 Not device with eprom is that it more is incremented after each location 31 connected 1Q. closely emulates the final rom programmed and the 4040 is 11 30 version of a one -chip microcom- clocked every time the eight -bit 12 29 11 puter during development of a counter passes through zero. 13 28 2 circuit. Using external memory Thus low -order address lines on w 27 26 as the program store means that the 28 -pin socketlact as the 19 16 25 signal lines have to act as data and higher -order address lines on the 18 i.n1L 24 address lines which severely res- 40 -pin one. Four such lines have (17\:-.218 23 tricts their use as general i/o lines. been laid to the socket so that the 19 22 O 15 Further, as anything up to 16 pins adapter has the potential to pro- 20 21 CF are freed to act as i/o lines, use gram devices with up 4Kbyte of of the eprom version reduces the eprom. These don't exist yet but if need for peripheral i.cs. an 8750 is produced, the system Rather as with eproms, manu- is ready to program it. facturers saw the eprom micro- As mentioned earlier, the data 220 computer as a development tool lines are scrambled. This illus- IC203 IC 201 210 1C202 and thus a small -volume product. trates one of advantages of pro- out out n out 7810 78105 Just as with eproms, mánufactur- grammable over discrete logic. 1k8 1k8 ers appear to have been caught There are many occasions when a G ND GND ONO 1k8 o R202 R205 e R208 out by their massive use in pro- little software saves a lot of p.c.b . 15k 15k 15k duction as a means of maintaining design effort. Perhaps too few R201 R204 R207 product flexibility. Main suppli- electronic designers have to R203 R206 ers of eprom microcomputers are design their own p.c.bs as well! 'Let 5k 5k Sk 2N3904 Tr201 2N390á Tr202 2N3904 Tr20309 Intel and NEC, types offered In this case, the top five lines are being the 8741A, 8748, 8749 and reversed, D, going to D3, D3 to the more advanced 8751 and D7, D6 to D4 and D,1 to D6. As well Fig.5. 8741/8/9 start to list memory as a series of 8744. as being the optimum solution to microcomputer programming FFs. Note that as yet, no eproms Being 40 -pin i.cs the program- p.c.b. layout, this mirror trans- adaptor. Numbers in circles have been inserted into either the mer requires an adapter, which position allows the same software refer to pins on the eprom master or slave sockets. comes in the form of a small routine to both scramble the data programmer slave socket into When using the programmer, p.c.b. with a few components, a prior to programming and unscr- which this adaptor is plugged. do not remove or insert eproms 40 -pin zif socket and a 28 -pin able data read back for verifica- These extra components are from or into the slave socket plug. One adapter is suitable for tion. needed to drive the processor unless the OK or ERROR leds are programming 8741A, 8748 and To set up the adapter fit it to clock and switch voltage lit since the VP, programming vol- 8749 i.cs, Fig.5. Devices in the the programmer, select 8749 and levels. tage will be present on the slave 8748 series are more difficult of press the LIST button without a socket. During listing, all three program, needing three con- printer connected. Resistor A kit of parts for the R209 complete status leds stay off until the end of eprom programming unit trolled high voltages and multi- is adjusted to set the voltage on including transformer, zif the operation. When programm- plexed addresses and data. The pin 7 of the 40 -pin socket to 18V. sockets, unpunched case, ing, the end of the operation is programmer provides all of the Short of base of TrL02 to its emit- connectors, hardware and indicated by the PROGRAM led control signals and even scram- ter and set R2Ú6 to give 18V on pin programmed eprom but not going out and either the OK or bles data to and from the 40 -pin 25 of the 40 -pin socket. Finally, p.c.bs and parts for the ERROR leds lighting to indicate socket in order to made p.c.b. short the base of Tr201 to its microcomputer adaptor can be good or unsuccessful programm- layout simpler. emmitter and set R203 to give 21V obtained by sending £77.50 ing respectively. As the adaptor only has one on pin 26 of the 40 -pin socket. including postage but exclusive At the end of each line printed socket, direct copying of one 40 - After completing this procedure, of vat to John Adams at 5 The Close, Radlett, Hertfordshire, during listing, the programmer pin device to another is not-possi- switch the programmer off to telephone Radlett 5723. Parts for checks the keyboard so that a list- ble. A bigger p.c.b. would be clear the list instruction. Don't the adaptor excluding p.c.b. but ing may be interrupted by press- needed for this. Direct copying of forget to remove the shorts. including sockets are an extra ing and releasing the UP or these devices is not frequently £15.00. A disc with the SC84 DOWN key. If LIST is selected required so I opted for the control program is £5.50 and a printer is not connected, cheaper solution - one zif socket excluding vat but including the system will need to be costs more than the rest of the disc size, postage - please state switched off and then on again to adapter put together. The adap- A of p.c.bs including a etc. set regain always fits into slave plated -through and silk-screened control. ter the main circuit board are available socket as it needs high voltages from Combe Martin Electronics, Programming one -chip processors for both reading and writing. King Street, Combe Martin, North When the adaptor is used, the Devon EX34 OAD for £17 Design of this programmer is programmer should be controlled including UK/overseas postage. flexible enough to be adapted to by computer, whence all oper- Working of the programmer and The microcomputer virtually any eprom device, due ations except direct copying are the software controlling it are programming board is an extra primarily to the general-purpose possible. Copying can of course subjects of the next article. £4 including postage.

54 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com The 8048 8048 family is fully catered for. In particu- characteristics, values Internal facilities lar there are indexed instruc- There in are five types in this bytes tions of the 'get the byte family of one -chip microcom- An eight -bit counter/timer pointed to by the A register puter, namely the 8035, 8039, Type Internal rom Other ram capable of interrupting the from a particular page of rom 8049 and 8748, each with var- system is provided. When and put it in the A register' ying memory type/capacity, 8035 None 32 used as a timer it is clocked at form. This allows a particular see table. All can address up 8039 None 96 1/480 of the crystal fre- page to act as a very efficient to 4Kbyte of external program 8048 1K 32 quency; it can set a flag and area for look -up tables. rom, 8049 2K 9 256 byte ram and have interrupt the system when the There are basic arithmetic 32 bytes 8748 1K (eprom) 32 of dedicated ram. count passes through zero. and logical commands capable The processor's built-in clock of acting directly on the A I/O facilities generator requires only a register and input/output the expanders, FROG, an crystal and two capacitors ports, allowing direct maini- address -catching latch, ALE, externally. Only one capacitor pulation of from 1 to 8 bits Port zero is an eight -bit port a single -stepping input, SS, is required by the power -on a port. There are long jumps which may be used for paral- and an input forcing the pro- reset circuit. as well as short ones (i.e. lel i/o. When accessing cessor to access external Crystal frequencies for the within a page) which can be external memory, this port memory, whatever its type. 8048 may be as high 11MHz, conditional on zero in the multiplexes the lower eight The microprocessor this being divided by 15 to give. accumulator, the carry bit, bits of the memory address accesses external memory the basic instruction rate. A any of the accumulator bits, a and data read from or written automatically when a pro- typical crystal frequency is timer overflow, internal flags, to memory. Separate WR, RD gram -counter address 6MHz giving a cycle time of the test lines or the interrupt and PSEN signals are available exceeds the limit of the inter- 2.5µs and a basic timer unit of line. to strobe data to and from nal rom. The incrementing 80µs. Some 60% of the Z80 -style decrement and external memory and from section of the 8048 program instructions execute within jump -on -not -zero instruc- program memory respect- counter is actually only an 11 - one cycle. The remainder, tions (DJNZ) are available for ively. bit register. To access mostly immediate instruc- all 16R registers. Of particular On eight -bit port one, the 4Kbyte, an extra address line tions where a second byte of interest is a jump of the form lines may be used as individual is required so the contents of data has to be fetched as part go to the location pointed inputs or outputs. The output - the memory bank flag (MBF) of the instruction, take two to by the A register in the cur- structure of these lines is form the twelfth bit of the add- cycles. rent page, get the byte there interesting. When set high, ress. This bit is set or cleared Two identical banks of eight and put it into the lower byte only a weak pull-up resistance by the instructions SEL MBO &bit registers which may be of the program counter. This of about 50kQ2 holds the line and SEL MB1 and transferred alternated between are used allows very efficient transfer high but during the actual into the program counter on (similar to the Z80's). Two of execution to one of many transition from low to high, a the next jump or call opera- registers in each bank, R and routines depending on the strong pull up is temporarily tion. R1, may be used as pointers to contents of the A register. applied to ensure speedy ram for indirect operation, the Standard call and return action. In its high state, as others are solely general pur- mechanisms are used for sub- well as being a high output, pose. Lastly, the 8048 has routines although there are no the line may also be used as Programmer control lines an two settable and testable PUSH and POP instructions input. flags, one of which is automat- for storing information on the On port two, also eight bits, Line 8035 ically preserved during an stack. The stack is within an the upper four lines act in the interrupt . area of memory devoted to same way as those of port one. Data P1m17 bus to eproms ram and is eight return The lower four lines are avail- INT Serial data input addresses deep. When a sub- able for i/o but also output the To Serial hand -shake input Instructions routine is called or an inter- higher-order memory address P24 Select EXPO rupt accepted, the 12 -bit pro- lines during external program P25 Select EXP1 Serial handshake output gram counter and four status memory access, and act as a P26 Serial data output Data movement between flags (carry, half-carry, inter- four -bit command and data P27 registers, the accumulator nal zero register bank) bus between the microcompu- and are and internal/external memory pushed on to the stack. There ter and any expanders fitted to the system. are two types of return Line ICs (EXPO) ICs (EXP1) instruction. One just rein- Test inputs To and T, can be states the program counter, used as subjects of conditional the other, designed to make jumps in the program. A spe- P40 PSU on LED row 0 P41 PSU select 12V LED row 1 the call operation more trans- cial instruction sets To and T1 P42 PSU select 21V LED row 2 parent, reinstates flag bits can be P43 Slave )(cc used as subjects of con- select LED row 3 too. The latter type is usually ditional jumps in the program. P5, S22 through RL2 LED column 0 S20 1 used for interrupts. A special instruction sets To as Psi LED column Counter clock, M22 LED column 2 a clock output running at P52 one P53 Counter reset LED column 3 third of the crystal frequency. so RL1, S23 Sounder Test line T, may also be used P61 RL2, S22 OK led as the input to the event coun- P62 RL3, S1, M1 ERROR led RL4, S26, M26 PROG led ter. An active low P63 maskable P76 Al2, M2, S2 S1 UP key interrupt input, INT, may also P71 A13, M26, S26 through RL4 S2 DOWN key act as a test input for condi- P72 A74, M27, S27 S3 PROG key Note, abbreviation M refers to pins on tional jumps. P73 A15, M1 through RL3 S4 LIST key the master zif socket, S to pins on the slave socket (last month's circuit Other pins are a strobe for diagram).

ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com SEMICONDUCTOR SURVEY Semiconductor suppliers An Electronics and Wireless World survey

ABACUS ELECTRONICS, At EWW we receive a regular stream of enquiries for the Telephone: 0992 444111 Kennett House, sources of components. In order to answer it is often quite a c.w.o. Mail-order catalogue. Pembroke Road, task to wade through suppliers' catalogues to find the Newbury, Berks RG13 1 BX. CONSORT ELECTRONICS, Telephone: 0653 30680. information. We have constructed this list in order to provide Rosebank Parade, Trade. Exclusive distribution of some clues as to the possible whereabouts of semiconductors. Reading Road, Scanbe, Holmberg, TEEE. It is not comprehensive but we have tried to identify those Yateley, Camberley, Surrey GU17 7RN. companies who do supply the end user rather than Telephone: 0252 871717 ACE MAILTRONIX, to a 3A Commercial Street, representative or agency companies. We hope publish list c.w.o. Exclusive distribution: Batley, W. Yorks WF17 5HJ. of manufacturers and their UK agents - as a supplement to Solitron, Microsemi. Telephone: 0924 441129 this survey at a later date. C.W.O. We have had direct contact with all the companies listed CURZON ELECTRONICS, either through their postal answers to our questionnaire or by 17c London Street, ACTIVE ELECTRONICS, importance Basingstoke, Hants RS21 1 NT Duke Street, telephone. One question which we considered of Telephone: 0256 51841 High Wycombe, Bucks HP13 6EE. was whether the distributors were willing to sell "small Trade. Telephone: 0494 441129 quantities to private buyers." We were pleased and a little C.W.O. Speciality: Computer surprised that a large proportion of them were and we have DTV GROUP, peripherals. . indicated this by C.W.O. (cheque with order), after their 2 Ernest Avenue, West Norwood, London SE27 ODJ. ADD-ON DEVICES, addresses. Others were marked `trade'. We also asked if any of Telephone: 01 670 6166 11 Shield Road, their lines were exclusive to the individual company and if c.w.o. Retail counter. Ashford Industrial Estate, they specialized in any particular field. Their answer are Ashford, Middlesex TW15 1 AU. able to respond Telephone: 07842 47141. recorded in each entry. All of them claim to be D.W. ELECTRONICS c.w.o. Minimum order £25. to an order on the same day or within 24 hours. Most of them (CAMBRIDGE), Speciality: Surface -mounted are willing to identify substitutes and provide them as Tudor House, High Street, components. alternatives if the desired components are not available, but Fenstanton, Huntingdom PE18 only after consulting the customer. 9JZ. AEROMEL INTERNATIONAL, Telephone: 0480 67666 17 Harland Way, All say that they can provide data sheets for the products c.w.o. Southborough, they distribute and do not charge if the product is purchased OTQ. Tunbridge Wells, Kent TN4 at the same time. Most companies also said that they were DAGE EUROSEM, Telephone: 0892 37977 to technical advice on the the applications of Rabans Lane, Milspec. devices. abot offer Trade. Speciality: components. Aylesbury, Bucks and HP19 3RG ALTEK MICROCOMPONENTS, Considering the current interest in microcomputers Telephone: 0296 32881 22 Market Place, communications, we thought it would be interesting to see if c.w.o. Speciality: Digiral i.cs, Power Wokingham, Berks RG11 1AP. any of the companies offered data bases and computerized fets. Telephone: 0734 791579 ordering. None of them did, but a few were thinking of it or c.w.o. Speciality: Microprocessors memories. were installing equipment to do so. DIALOGUE DISTRIBUTION, and Watchmoor Road, Camberley, Surrey, GW15 3AQ AMBAR COMPONENTS, AVIQUIPO OF BRITAIN, BI-PAK SEMICONDUCTORS, Telephone: 0276 682001 Gatehouse Road, St. Peters Road, 63A High Street, c.w.o. Speciality: Digital i.cs, Power Aylesbury, Bucks HP19 3ED Maidenhead, Berks. Ware, Herts SG12 9AG. fets. Telephone: 0296 34141 Telephone: 0628 34555 Telephone: 0920 3182 c.w.o. Speciality: Microprocessors c.w.o. "We can supply any c.w.o. etc. semiconductor." DISTRIBUTED TECHNOLOGY, House, BOSLEDGE, Talboys Surrey RH8 9PA. ANGLIA COMPONENTS 27 Church Street, Oxted, Telephone: 08833 6161 Burdett Road, BARLEC-RICHFIELD Manachester, M4 1 PE. Exclusive distribution: Wisbech, Cambs PE13 2PS. Foundry Lane, Telephone: 061 834 7339 c.w.o. Power Telephone: 0945 63281 Horsham, W. Sussex RH13 5PX. Trade. Trelec, TIC. Speciality: c.w.o. Exclusive distribution: Telephone: 0403 51881 Semicond, r.f. devices. Promax Trade. BOSLEDGE, 27 Church Street, ELECTRONIC RESOURCES, ARIES ELECTRONICS, BARRIE ELECTRONICS, Manchester, M4 1 PE. Henlow Trading Estate. Valley Road, Telephone: 061 834 7339 159 Boyn Unit 221, Stratford Workshops, Henlow, Beds SG16 6DS. 6DT. Maidenhead, Berks SL6 Burford Road, London E15 2SP Trade. Telephone: 0462 815555 Telephone: 0628 37431 Telephone: 01 555 0228 c.w.o. c.w.o. Retail. Speciality: Transformers. CAMPBELL COLLINS, 162 High Street, ARROW ELECTRONICS, Stevenage, Herts. ELECTROVALUE, Leader House, BETA DEVICES, Telephone: 0438 69466 28 St. Judes Road, Coptfold Road, 6 Sun Street, Englefield Green, Brentwood, Essex CM14 4BN. Waltham Abbey, Essex. CIRKIT, Egham, Surrey TW20 OHB, Telephone: 0277 219435 Telephone: 01 971 6529 Park Lane, Telephone: 0784 33603 Trade. c.w.o. Postage "at cost." Broxbourne, Herts. c.w.o. Retail shop.

56 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com FARNELL ELECTRONIC Telephone: 07842 46273 c.w.o. Speciality: Microprocessor PRONTO ELECTRONIC COMPONENTS Trade. and memeory i.cs. SYSTEMS, Canal Road, Leeds, Yorks 466 Cranbrook Road, LS12 2TU. IMPULSE ELECTRONICS, Telephone: 0532 636311 MERLIN ELECTRONICS, Gants Hill, Trade. Hammond House, Granada House, Ilford, Essex IG2 6LE. Caterham, Surrey CR3 6XG. Gabriels Hill, Telephone: 01 554 6222 G.E. Electronics (London) Ltd. Telephone: 0883 46433 Maidstone, Kent ME15 6JP. c.w.o. Speciality: I.cs (no discrete Earley House, Trade. Telephone: 0622 678888 components) 182 Campden Hill Road, c.w.o. London W8 7AS. JATA (ELECTRONICS), QUARNDON ELECTRONICS Telephone: 01 727 0711 9 Heaton Road, MICROLOG, (SEMICONDUCTORS), c.w.o. Bradford, W. Yorks BD8 80K. Elizabeth House, Slack Lane, GAIN ELECTRONICS, Telephone: 0724 42636 Duke Street, Woking, Surrey GU21 Derby DE3 3ED. 63 High Street, 5BA. Telephone: 0332 32651 Prices Risborough, JERMYN DISTRIBUTION, Telephone: 04862 66771 Trade. Aylesbury, Bucks. Vestry Estate, c.w.o. Speciality: Linear i.cs, Telephone: 084 447116 Sevenoaks, Kent 0732 450144 programmable logic arrays. RS COMPONENTS, c.w.o. "Visitors welcome." Trade. PO Box 427, MICROMARK ELECTRONICS, Epworth GOTHIC Street, CRELLON, L.S.W. Components Service, 380 Bath Road, 157 Boyn Valley Road, London EC2P 2HA. Wyvern House, Slough, Berks SL1 6JE. Maidenhead, Berks SL6 4DI Telephone: 01 253 1222 Telephone: 06286 4300 High Street, Telephone: 0628 72631 RS components are sold as 'own c.w.o. It is necessary to open an Bognor Regis, W. Sussex P021 c.w.o. brand' and therefore they do not account. Exclusive distribution: 1 S P. list their manufacturers. Most Varo, Arif a. Telephone: 0234 826824 MS COMPONENTS, semiconductors in the RS Zephyr House, catalogue are listed as 'similar to' GREENWELD, LANGREX SUPPLIES, Waring recognised 443 Millbrook Road, Street, components. Trade Climax House, W. Norwood, Southampton SO1 OHX. London SE27 9LH. only. Telephone: 0703 772501 Fallsbrook Road, Telephone: 01 670 6166 Retail shop. London SW16 6ED. c.w.o. Trade/retail counter. RASTRA ELECTRONICS, Telephone: 01 677 2424 275 King Street, HARMSWORTH, TOWNLEY & CO. c.w.o. Speciality: Obsolete MCLELLAND ELECTRONICS, Hammersmith, London W6 9NF. Hareh ill , components. 3a Bankfield Industrial Estate, Telephone: 01 748 3143. Todmorton, Lancs OL14 5JY. Kitson Road, Leeds LS10 3YY. c.w.o. or credit card. (£10 Telephone: 070 681 4931 MCP Electronics, Telephone: minimum) Retail c.w.o. 0532 460572 counter. 38 Rosemount Road, Trade. HAWKE ELECTRONICS, Alperton, Middlesex HAG 4PE REGISBROOK, Amotex House, Telephone: 01 902 6941 NEWTEC DISTRIBUTION, 215 King Street, 45, Hamworth Road, c.w.o. (£25 minimum order) Beadle Trading Estate, Reading, Berks RG1 4LS. Sunbury -on -Thames, Middlesex. Speciality: r.f. and digital signal Ditton Walk, Telephone: 0734 665955. Telephone: 01 979 7799 processing. Cambridge CB5 8QD. Necessary (but easy) to open an c.w.o. Telephone: 0223 211211 account MDL COMPONENTS, HAWNT ELECTRONICS, c.w.o (formerly Lock Distribution) 10 Cowley Road, Firswood Road, S.E.M.E. Ltd, Garretts Green, Nuffield Industrial Estate, NORSEM ELECTRONICS 2E Saxby Road Industrial Estate, Poole, Dorset. BH17 7UJ. Birmingham B33 OTQ. GROUP, Melton Mowbray, Leics LE13 1 BS. Telephone: 021 784 2485 Telephone: 0202 681331 4 Heron Industrial Estate, Telephone: 0664 65392 c.w.o. Spencers Wood, Trade. HB ELECTRONICS, Reading, Berks. Lever Street, MACRO -MARKETING, Telephone: SEMELAB, Bolton, Lancs BL3 6BJ. 0734 884588 Burnham Lane, Bank Street, Telephone: 0204 386631 Trade. Slough, Berks SL1 6LN. Lutterworth, Leics. Telephone: 06286 4422 HERO ELECTRONICS, NEWECO, Telephone: 04555 4711 c.w.o. or A/c. Particularly proud Dunstable Street, of Cresto House, Trade. their technical advice department. Ampthill, Beds MK45 2JS Water Lane, Telephone: 0525 405015 Wilmsow, Cheshire. SEMI COMPONENTS, c.w.o. Speciality: Sharp MAPLIN ELECTRONIC SUPPLIES Telephone: 0625 529523 Vine House, components, opto -electronics. PO Box 3, Rayleigh, Essex SS6 Trade. 104 Ashley Road, 8LR. Walton -on -Thames, HI -TEK DISTRIBUTION Telephone: 0702 554155 Trafalgar Way, PHAB ELECTRONICS, Surrey KT12 1 HP. Mail-order catolgue and retail Telephone: 0932 241866 Bar Hill, Cambridge CB3 8SQ. 7 Centenary Estate, shop. C.w.o. Speciality: Microprocessors Telephone: 0954 81996 Jeffreys Road, Trade. memory and display. MARCO TRADING, Enfield, Middlesex EN3 7UF. Telephone: 01 805 4060 HOUSE OF POWER, The Maltings, SEMICOMPS, c.w.o. (£10 minimum order). Electron House, Cray Avenue, High Street, Halifax Road, Orpington, Kent BR3 3QJ. Wem, Shropshire SY4 SEN. Keighley, W. Yorks BD21 5HT. Telephone: 01 667 1531 Telephone: 0939 32763 PHILIPS SERVICE, Telephone: 0535 65191 c.w.o It is necessary (but easy to 604 Purley Way, open an account. Mail-order catalogue and retail Necessary (but easy) to open an Exclusive Whaddon, distribution: Symbol shop. account Croydon, Surrey CR9 4DR. HUNTER ELECTRONIC MEDL DISTRIBUTION, Telephone: 01 686 0505 SEMICONDUCTOR SPECIALISTS, COMPONENTS, East Lane, (Spares for Philips and Mullard Carrol House, Unit 3, Central Estate, Wembley, Middlesex HA6 7PP. equipment) 159 High Street, Denmark Street, Telephone: 01 904 9303 Yewsley, Maidenhead, Berks SL6 7BN. Trade. POLAR ELECTRONICS West Telephone: 0628 75911 Drayton, Middlesex UB7 Trade. Europa House, 7XB. MEMEC, West Street, Telephone: 08954 45522 HY-COMP, Thame Park Road, Leighton Buzzard, Beds LU7 7ND. Trade. 11 Shield Road, Thame, Oxon OX9 3XD. Telephone: 0525 377093 Continued on page 81 Ashford, Middlesex TW15 1AU. Telephone: 084 421 4561 c.w.o. Table on pages 60 & 61 ELECTRONICS & WIRELESS WORLD DECEMBER 1984 57

www.americanradiohistory.com TERMS OF BUSINESS

* All prices exclude V.A.T. and carriage. Please add * Goods incorrectly ordered cannot be accepted for carriage to order total before adding V.A.T. replacement without our prior agreement. Due to high processing costs, a minimum of 15% handling * Carriage charges extra on all orders as follows: may be levied on any returns or cancelled Components £0.75 charge Books/Data/Software £2.00 orders. Printers, Monitors, Disc drives, etc. £4.50 * We will issue a full immediate refund, if requested, _ for out of stock items. * Strictly cash with order or credit card (Access or VISA) only. * All items carry full manufacturers warranty. ech HI TECH COMPONENTS. * Delivery is normally from stock but please allow up * A V.A.T. receipt will be supplied with all orders. to 28 days. * Prices quoted are correct at the time of going to * Any query qr complaint regarding an order should press but we reserve the right to effect changes be made in writing within 7 days of receipt of the without prior notice. order. No telephone queries will be entertained. 6502 8086 MEMORIES - EPROM 75173N 1.44 F.D. CONTROLLERS FAIRCHILD 74HC251N¡1.03 74L522 0.25 4033 2.40 4078 0.25 75174 2.82 74HC253N11.03 7415221 1.08 4034 1.00 4081 0.40 35.00 FAST FAMILY FAMILY 2532-3004z 4.95 75175 1.96 8272 74HC257N 1.03 7415240 1.40 4035 0.54 4082 0.25 3.95 FD1771P 30.00 74F00PC 6502 3.50 8086 29.50 2532-450ns 75182 0.50 0.60 74HC266N .92 7415241 1.40 4040 0.65 4085 0.6E FD1791 15.50 74F04PC 6502A 4.95 8088-2 22.50 2564-3°°m6.95 75183 0.50 0.60 741-(273N .24 74L5242 1.36 4041 0.36 4086 0.40 3.95 P01791-02 6520 2.25. 8216 0.75 2708-450ns 75188 0.86 11.00 74F08PC 0.65 74HC27N .60 7418243 1.36 4042 0.76 4093 0.32 2716-45Ons F01793 18.40 74F109PC 6520A 2.45 8237A-5 23.50 3.50 75189 0.86 0.65 74HC280N .26 7418244 1.40 4043 0.64 4099 0.50 RAIL 7.95 F01793-02 11.00 74F11PC 6522 3.40 8251A 7.50 2716-3 75451 BP 0.22 0.52 74HC32 .40 74L5245 1.95 4044 0.62 4502 0.8E F01795 6522A 4.45 8253-5 7.50 2732-350ns 4.95 75452BP 0.29 25.00 74F138PC 0.52 74HC373N .40 74LS248 1.16 4045 2.00 4507 0.47 4.45 F01797 21.00 6532 5.45 8255A-5 7.00 27.2-4-'.^, 754538E 0.22 74F138PC 1.26 74HC374N 2.40 7415249 1.16 4046 0.77 4508 0.9E WD1691 14.00 74F139PC 6532A 5.95 8259A 6.60 2764-200ns 7.95 75454BP 0.22 1.26 74HC393N 1.78 74L5251 0.78 4047 0.50 4510 0.6E 5.15 WD2143 12.00 6551 5.95 8272 35.00 2764-25Ons 75468N 0.88 74F151 1.26 74H(4002 0.64 7418253 0.78 4048 0.40 4511 0.65 8284A 9.50 2764-300ns 4.75 75491N 0.31 74F153 1.26 74HC4017 1.16 74L5257 0.78 4049 0.50 4512 0.40 10.95 DATA CONVERTERS- 80086 46.65 27(64-250ns 75492N 0.41 74F157 1.30 74HC4020 1.46 7418258 0.78 4050 0.49 4514 1.7E 10.45 6800 80088 46.65 27C64-300ns AY -3-1015 3.50 ZN425E-8 3.76 74F158 1.17 74HC4024 1.20 7415259 1.77 4051 0.52 4515 1.84 82(52 15.68 27128-250ns 19.00 AY -3-1270 9.40 ZN425J-8 8.00 74F161 2.34 74HC4040 1.46 741526 0.30 4052 0.48 4516 0.6E FAMILY 82(54 19.04 27128-300ns 16.00 AY -3-8910 6.40 ZN426E-8 1.90 74F164 1.68 7411(4060 1.46 7415261 2.60 4053 0.66 4518 0.4C 74F175 1.82 74HC4075 82(55A212.98 AY -5-3600 8.84 ZN427E-8 6.68 0.64 74L5266 0.35 4054 1.30 4519 0.25 6800 2.15 92(594 15.22 MEMORIES RAM DP8304 4.50 ZN4271-8 12.50 74F181 3.90 74HC42N 0.90 74LS27 0.25 4055 0.72 4520 0.9E 2.15 6800 2N428E-8 5.10 74F189 5.10 74HC4511 74L5273 1.35 4060 0.68 4521 1.32 8qp 82(82 6.26 4116-150ns 1.28 L203 0.99 2.51 6802 82C84A 8.94 4116-200ns 1.20 LF398 3.80 ZN4281-8 9.70 74F190 3.20 74H(4514 3.76 7418279 0.77 4063 0.60 4522 0.84 6809E 6.25 82(88 16.80 4164-15Ons 4.45 LM301AN 0.30 ZN429E-8 1.60 74F191 3.20 74HC4538 2.36 74L528 0.25 4066 0.50 4526 0.52 6809P 6.25 4416-200ns 4.70 LM308AN 0.94 ZN4320-10 20.29 74F194 1.68 74HC4543 3.04 7415283 1.00 4068 0.25 4527 0.52 6810 1.70 4532-200ns 2.45 LM308N 0.56 ZN432E-10 13.00 74F20PC 0.52 74HC51N 0.64 74L5290 0.86 4069 0.40 4528 0.4E 6821 1.70 Z80 4564-15Ons 4.45 LM311N 0.60 ZN433(J-10 25.00 74F240 3.16 74HC533N 2.40 7415293 0.86 4070 0.40 4532 0.6E 6840 3.70 FAMILY 8118-100ns 1.95 LM317MT 0.80 ZN434 0.98 74F241 2.42 74HC534N 2.40 74L530 0.25 4071 0.40 4541 0.82 6845 6.45 74F243 2.80 4543 0.60 Z8OACPU 2.99 81256-150ns 25.00 LM317T 1.06 ZN435 4.38 74HC58919 1.72 741832 0.25 4072 0.40 6850 1.70 74F244 2.96 74HC58N Z8OACTC 2.99 8416-200ns 6.00 LM319N 3.30 ZN436E 1.26 0.64 74LS33 0.30 4073 0.40 4553 2.40 6862 3.75 74F245 6.08 74HC595N Z8OADMA 7.95 8416-LP-200ns 6.40 LM324N 0.50 ZN440 55.00 1.84 74L5365 0.55 4075 0.46 4555 0.4E 6875 4.95 74F251 1.26 74HC597N 0.44 Z80APIO 2.99 8417-200ns 6.00 LM337T 1.20 ZN441 46.80 1.72 74L5366 0.55 4076 0.48 4556 68600 4.30 74F253 1.26 280A510-0 7.95 8417-LP-200ns 6.40 1M339 0.48 ZN447 7.80 74HC73N 0.84 74L5367 0.55 4077 0.40 4585 0.4E 68809 9.95 74F257 1.26 180A510-1 7.95 LM339N 0.48 ZN448E 6.66 74HC74N 0.84 74L5368 0.55 68810 1.88 74F258 1.34 74HC75N 74L537 Z8OA510-2 7.95 MEMORIES - RAM LM348N 0.64 2N4481 12.48 0.92 0.25 CRYSTALS 68821 3.70 74F2ß0 1.7474HC76N 1.50 ZßOBCPU 5.95 *ZERO POWER ZKXB LM35OT 3.12 ZN449 2.72 0.64 7415373 A111B 1MHz 4.50 68840 6.60 LM358N 0.60 2NÁ1341 22.50 74F2ß3 1.74 74HC85N 2.02 74L5374 1.50 280807( 5.95 * A112A 1 008MHz 4.00 68850 1.58 MOS 74F32PC 0.52 7415375 Z80BP10 5.95 LM3900 0.68 ZNA234E 9.40 74HC86N 0.80 0.75 A113A 24576MHz 3.0C 68654 7.95 74F352 1.26 7415377 1.50 280B510-0 9.95 MK48202B-15ons 32.00 LM393N 0.48 74HCUO4N 0.80 A110Á 4MH76MHz 1.25 74F353 1.26 74L5378 Z80B510-1 9.95 MK48202B-200ns 24.00 LM725CN 3.00 1.22 6MHz 1.25 VOLTAGE REF. 74F373 3.16 A132A 2808510-2 9.95 MK482026-250ns 23.00 7410E 0.16 7ÌL 7415379 1.50 Á132A 6MHz 1.70 ZN404 0.50 74F374 3.16 74L53ß 0.25 Z80510-0 6.00 LM747CN 0.60 741800 0.25 Á140A 8MHz 1.25 7N423 0.98 74F379 1.83 74L5386 0.50 280510-1 6.00 BIPOLAR PROMS LM748CN 0.30 74L501 0.25 A169A 3.6864MHz 2.05 1N458 0.92 74F381 6.62 74L5390 1.10 Z80510-2 6.00 TBP185030N 1.54 MC1413P 0.80 74L502 0.25 Á773A 9.8304MHz 2.75 ZN458A 0.92 74F382 4.22 7415393 1.10 TBP18SA030 1.38 MC1416 0.80 74L503 0.25 Á182A 79.6608MHz 2.50 ZN458B 1.12 74F398 3.16 74L540 0.25 6805 FAMILY TBP24510N 2.06 MC14411 10.10 741804 0.25 025 1.90 74F399 74L542 0.85 1BP24541N 6.68 MC14412 14.20 ZNREF 2.70 74L505 0.25 DIL SKTS TIN MC1468052P 12.60 MC1458CPl 0.35 ZNREF 040 1.90 74F521 2.76 74L547 1.00 7.20.TBP24581N 5.50 741808 0.25 MC146818P MC14951 6.30 ZNREF 050 1.90 74F533 3.16 741548 1.00 1+ 1004 8.80 TBP24SA1ON 1.40 74L509 0.25 MC146823P MC1496P 0.70 ZNREF 062 1.90 74F534 3.16 741549 1.00 07070802 8 PIN 0.07 0.05 75,00 TBP24SA41N 4.40 741510 0.25 MC68705KT3 MC1723P 0.40 ZNREF 100 3.05 74F537 6.02 741551 0.25 07071402 14 PIN 0.09 0.07 40.00 18P28122N 3.10 74L5109 0.54 MC68705R3L MC3242A 6.30 74F538 4.38 741554 0.25 07071602 16 PIN 0.09 0.07 TBP28LA22N 4.14 74L511 0.25 MC68705U3L 36.00 74F539 4.38 741555 0.25 07071802 18 PIN 0.15 0.10 TBP285166N 19.00 7418112 BUFFERS 74F64PC 0.52 0.54 7418670 2.30 07072002 20 PIN 0.19 0.14 TBP28542N 4.50 MC3340P 2.36 7415113 0.42 68000 FAMILY 1.90 811596 1.10 74F74PC 0.58 741573 0.30 07072202 22 PIN 0.21 0.15 TBP28546N MC3357P 74L5114 0.44 4.50ß11S97 1.10 74F86PC 0.77 74L574 0.35 07072402 24 PIN 0.24 0.16 50.00 MC3423PL 0.81 MC68000G10 7BP28586N 5.00 741812 0.25 2.90 811598 1.10 741575 0.50 07072802 28 PIN 0.26 0.17 M16800018 50.00 TBP285A42N 4.50 MC3441AP 7415122 0.75 2.90 8T26A 1.10 HIGH 741576 0.35 07074002 40 PIN 0.29 0.18 MC6800818 45.00 1BP285A46N 4.50 MC3446AP 74L5122 0.75 4.30 8128 1.10 74L578 0.35 MC6823018 19.50 1BP285A86N 8.62 MC3447P SPEED 7415123 2.30 3.99 8728A 1.10 74L583 0.90 DIL SKTS GOLD MC6845118 67.00 AM27513PVC 3.74 M(3448Á 7415124 0.49 M168901P 75.00 MC3470P 6.44 8T95 1.10 CMOS 741585 7.16 06060802 8PIN 0.16 AM27519PC 1.92 1.10 7418126 0.49 M03480 7.76 8197A 741586 0.42 06061402 74 PIN 0.20 ÁM278791 DC 15.00 74HC00N 0.42 741513 0.46 1.80 8T98 1.10 741590 0.66 6061602 16 PIN TI 9900 FAMILYMC3487ÁM278250( 15.00 7415132 0.73 0.21 74HCO2N 0.42 NE555P 0.25 741591 1.30 06081802 18 PIN 0.22 TM59901-95 4.50 ÁM275290( 6.46 74HCO3N 0.64 7415136 0.46 NE556CP 0.65 741592 0.66 06062002 20 PIN 0.28 TM59902 4.50 ÁM275350( 22.00 OPTOISOLATORS 74HC04N 0.44 7415138 0.77 R032513-1 9.40 741593 0.66 06062202 22 PIN 0.32 TMS9918 35.00 4N25 0.75 74HCOSN 0.42 7415139 0.77 Ro32513-U 9,qp 741595 0.77 06062402 24 PIN 0.42 TM59927 11.60 4N26 0.75 74HC107N 0.7Eí 74L514 0.80 MEMORIES E2 PROM TLO10-(P 0.44 06062802 28 PIN 0.46 7M8992ß 13.00 4N33 0.90 74HC109H 0.50 74L5145 1.23 CMOS X2804AP-300ns 14.95 TL061-CLP 0.28 06064002 40 PIN 0.6E TMS9929 13.00 74H110N 0.64 7415148 1.50 X2804AP-350ns 13.45 TL062-CP 0.47 TM59937 6.70 74HC112N 0.86 741515 0.25 4000 Series 0.95 UHF MODULATORS TMS9980 17.20 X2804AP-450ns 12.75 TL064-CN 74H(113N 0.86 7415151 1.10 4000 0.25 DIL SKTS W/WRAP TL066-CP 0.28 UM1111 2.95 TM59995 13.70 X2816AP-300ns 29.95 74HC132N 1.28 7415153 1.10 4001 0.52 TURNED PIN TLO71-CP 0.28 UM -1233 3.45 X2816AP-350ns 25.00 74HC137N 1.81 7415155 0.77 4002 0.25 1L072-CP 0.56 9090802 8 PIN 0.3E X28164P-450ns 22.50 74H1138N 1.20 7415156 0.77 4006 0.90 9091402 TL074-CN 1.10 14 PIN 0.75 0.29 VOLTAGE REG. 74H1139N 0.78 7415157 0.62 4007 0.25 9091602 16 PIN 0.86 TL081-(PN 1.16 74L5158 0.62 4008 0.92 9O91802 LINEAR/INT. DEV. 0.49 7805 0.75 74HC151N 18 PIN 0.96 TL082-CP 0.90 74L5160 0.80 4009 0.25 9092002 4702 8.90 11084 -CN 1.02 7812 0.75 74HC153N 20 PIN 1.08 74HC157N 1.02 7415161 0.80 4010 0.25 9092202 HCI-55564-5 10.66 TL091-CP 0.39 7815 0.75 22 PIN 1.18 7.50 74HC158N 1.02 7418162 0.80 4011 0.30 (Speech Synthesis) TL092-CP 0.72 78H055C 9092402 24 PIN 1.28 8.95 74HC160N 0.90 7415163 0.80 4012 0.25 9092802 ÁM79100( 34.88 TL094-CN 1.30 78H12.08( 28 PIN 1.50 9,95 74H(161N 0.90 7415164 1.10 4013 0.45 9094002 AM7911DC 34.88 71487-CP 0.59 78HGASC 40 PIN 1.70 1.51 7418165 1.30 4014 0.50 25152518PC 3.60 11489-CP 0.59 78105. 0.30 74HC162N 74HC163N 1.51 7415166 1.95 4015 0.65 25132521PC 3.28 TL494-CN 1.99 78112 0.30 74HC164N 0.95 7418173 1.13 4016 0.46 ZIF SOCKETS 25L52538PC 2.72 TL496-CP 0.59 78115 0.30 7.50 74HC165N 2.24 7415174 1.30 4017 0.63 08082402 24-P1N 5.70 25L52539PC 2.72 TL507-CP 1.22 785400M 1.35 7415175 0.96 4018 0.46 08082802 28 PIN 6.90 261537PC 2.62 6.08 7ß540P( 3.00 74HC173N ZN450-E 74HC174N 0.80 7415181 2.09 4019 0.39 08084002 40 PIN 8.25 Hi -Tech 261532P1 2.62 7.40 7905 0.95 ZN457-E 0.78 7415190 0.98 4020 0.45 6402 6.40 ZN451-K1T 29.95 7912 0.95 74HC175N components 75107BN 0.69 7915 0.95 74HC194N 1.28 7415191 0.75 4021 0.56 0.86 LM309K 0.95 74HC195N 1.28 7415192 1.10 4022 0.42 4023 0.34 75150E 0.86 LM317K 2.45 74H120N 0.40 7415193 1.10 dri"ilb75110ÁN 1.80 7415194 0.78 4024 0.66 75154N 1.05 LN323K 4.95 74H1237N 7415195 4025 0.25 2.30 LM338K 4.50 74HC240N 1.38 0.78 7418196 1.10 4026 0.74 75160AN 2.60 74HC241N:1.34 dilA75159 7415197 4027 0.52 75161AN 2.82 74HC242N 2.24 1.10 74HC243N 2.24 74L520 0.25 4028 0.34 74HC244N,1.32 741521 0.25 4031 0.93 0379 4131 75172NG 14.08.96

ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com PART NO. DESCRIPTION MAIL ORDER BBC MICROS AND ACCESSORIES PRICE ANB01 BBC Model B Micro £325.00 ANB02 BBC Model B Micro with Econet I/F £385.00 ANB03 BBC Model B Micro with Disc I/F £406.00 ANB04 BBC Model B Micro with Disc & Econet £445.00 ALA01 Acorn Electron £139.00 ANB21 DNFS ROM £17.91 ANB23 Disc Interface Kit £71.65 ANB14 Speech Interface £40.00 ANK01 IEEE488 Interface Adaptor £277.75 corn ANB22 Econet I/F Kits £35.00 ponents BBC 45 Joysticks GILRAY ROAD, DISS,NORFOLK. TEL: 0379 4131 E8.00 STAND Monitor Stand £7.50 SRE1 Sideways ROM Expansion Board £25.95 DISC-DRIVES WITHOUT POWER SUPPLY 3B£ 30 Single 100k TEC 40 track single sided £99.95 BBC31S Single 100k TEC (expandable to dual) 40 track £115.00 BBC31D Dual (2 x 100k) TEC 40 track single sided £225.00 INSULATION BBC34 Single 400k TEC 80 track double sided £174.00 DISPLACEMENT CABLE ASSEMBLIES DIP JUMPERS BBC34S Single 400k TEC (expandable to dual) 40/80 track switchable CONNECTOR SYSTEM double sided £194.00 Single Ended BBC345W Single 400k TEC 40/80 track switchable double sided 'HEADERS OPEN IDC JUMPERS £184.00 - 24" cable BBC 340 Dual (2 X 400k) TEC 40/80 track switchable double sided £310.00 SHROUDED OPEN SINGLE ENDED - STRAIGHT 14 pin 1.73 BBC34S/80 Single 400k TEC (expandable to dual) 80 track double sided £184.00 90' PINS 36" cable IDC socket 16 pin 1.90 BBC34D/80 Dual (2 X 400k) TEC 80 track double sided £300.00 ' 10 way 0.86 0.65 0.47 10 way 1.72 24 pin 2.73 14 way 1.22 0.83 0.59 14 way 2.07 40 pin 3.96 DISC DRIVES WITH POWER SUPPLY 16 way 1.34 0.92 0.65 16 way 2.22 BBC3OP Single 100k TEC 40 track single sided with P.S.U- 20 way 1.36 1.13 0.77 20 way 3.14 Double Ended £130.00 BBC31SP Single 100k TEC (expandable to dual) 40 track with P.S.U. 26 way 1.70 1.40 0.95 26 way 3.75 6'cable 12"cablel18"cable £150.00 BBC31DP Dual (2 X 100k) TEC 40 track single side with P.S.U. £250.00 34 way 2.04 1.78 1.19 34 way 3.98 14 2.74 2.84 2.94 BBC34P Single 400k TEC 80 track double sided with P.S.U. £209.00 40 way 2.28 2.07 1.37 40 way 4.23 16 3.03 3.14 3.25 BBC34SP Single 400k TEC (expandable to dual) 80 track with P.S.U. £229.00 50 way 2.70 2.54 1.67 50 way 5.36 24 4.18 4.36 4.55 BBC34DP Dual (2 X 400k) TEC 40/80 track switchable with P.S.U. £345.00 60 way 3.20 3.02 1.96 60 way 6.36 40 5.89 6.18 6.47 MECHANISMS SOCKETS DIP PLUGS D -TYPE DISC DRIVE CONNECTING CABLES FB501 10 way 0.88 14 way 0.92 PLUGS 34 way card edge to 34 way card edge 1M 11.30 TEC 100k single sided £91.00 FB504 14 16 34 way card edge to 2 X 34 way card edge TEC 400k double sided £150.00 way 1.06 way 1.06 9 way 1.38 1.5M 18.00 34 way card edge to 34 IDC 16 way 1.16 24 way 1.60 15 way 1.85 way SKT (BBC) 1M 8.501 LOPPY DISCS 34 way card edge to 2 x IDC 20 way 1.38 40 way 2.40 25 way 2.52 34 way KT (BBC) I.5M 14.50 26 way 1.66 BBC Power Cable Single Drive 3.50 MD-1C/B Nashua single sided, single density 40 TRANS. 37 way 3.34 - track (10 discs) E 12.00 34 way 1.94 BBC Power Cable - Dual Drive 4.75 MD-1 DC/B Nashua single sided, double density 40 track (10 discs) £13.00 40 way 2.08 CONNS. MD 2DC/B Nashua double sided, double density 40 track (10 discs) £15.50 RIBBON CABLE (PRICED PER FOOT) BBC MICRO MD-2FC/B 50 way 2.78 10 way 0.86 Nashua double sided, quad density 80 track (10 discs) E1785 GREY 60 way 3.34 way 1.17 RAINBOW CONNECTORS 16 r, 0.16 0.25 SPECIAL OFFER 20 way 1.37 10 0.16 0.25 DIN PLUG 7 PIN 0.40 26 way 1.67 BBC40TD BASF double sided, double density 40 track (10 E14 14 0.21 0.35 DIN PLUG 6 PIN 0.40 discs, 00 CARD 34 way 1.87 15 0.22 0.37 DIN PLUG 5 PIN 180° EDGE 40 way 2.23 0.40 ISC STORAGE BOXES 16 0.23 0.39 DIN PLUG 5 PIN DOMINOE 0.40 10 way 1.84 D -TYPE 0.28 0.48 POWER PLUG (36" CABLE) 3.00 MDT25/3 31" Flip 'N' file Micro disc box (cap. 25) £7.75 20 way DT25/5 S;' Flip 'N' file lockable 3,14 SOCKETS 20 0.34 0.60 ANALOGUE INPUT PLUG 2.25 disc box (cap. 25) £18.77 26 way 3.80 26 0.35 0.62 S WAY DIN SKT 180° 0.90 DT60/5 51" Standard lockable disc box (cap. 60) £10.65 34 way 4.90 9 way 1.47 34 0.45 0.80 5 WAY DIN SKT DOMINOE 0.90 40 way 5.52 15 way 2.02 40 0.52 0.92 6 WAY DIN SKT 0.90 ONITORS 50 way 6.68 25 way 2.90 50 0.64 1.14 7 WAY DIN SKT 0.90 9MON 9 inch green screen high resolution NEC high quality monitor £125.00 60 way 8.06 37 way 3.97 60 0.76 1.35 15 WAY DIN SKT 2.15 12MON 12 inch green screen high resolution NEC high quality monitor £135.00 1431 Connecting cables Microvitec 14' RGB colour monitor £175.00 for personal computers 1441 Microvitec 14' RGB colour monitor high resolution £410.00 A comprehensive range of high quality interconnecting cables for popular micro computers. All cables 1451 Microvitec 14° RGB colour monitor medium resolution £295.00 utilise high quality connectors and are individually tested to ensure trouble free use 1431/AP/MS Microvitec 1431 PAL & RGB inputs and sound facility - £225.00 Part number Description Computer BC COMPATIBLE SOFTWARE Video cables SBB03 View Rom £45.00 SBB04 View Printer CON100 Phono plug to phono plug (2M) Driver E7.50 1.20 AE520 Fileserver CON101 Phono plug to BNC plug (2M) Level 1-40 track £80.50 2.95 AES21 Fileserver CON102 BNC plug to BNC plug (2M) Level 2-80 track £202.00 3.95 SNB08 Acornsoft Invoicing program CON107 6 pin DIN to open end (1M) BBC 1.05 £16.00 SNB09 Acornsoft Mailing System program £16.00 CON108 6 pin DIN to 6 pin DIN (1M) BBC 1.50 SNB10 Acornsoft Accounts Receivable program CON119 Phono plug to coax plug 1.35 .£16.00 SNB11 Acornsoft Stock Control program CON160 DIN plug to 2 phono plugs Dragon 1.20 £16.00 SNB12 Acornsoft Order Processing program f16.00 Cassette recorder cables SNB13 Acornsoft Acounts Payable program £16.00 SNB14 Acornsoft Purchasing program £16.00 SNL01 Forth 40 track CON109 7 pin DIN to open end BBC 1.25 - £15.00 CON110 7 SNL02 Lisp 40 track £15.00 pin DIN to 2 x 3 5mm + 1 x 2.5mm 1/plug BBC 2.50 - SNL04 Microtext 40 track -. CON111 7 pin DIN to 5 pin DIN + 2.5mm 1/plug BBC 2.50 - £47.50 CON118 5 pin DIN to 2 x 3.5mm 1/plugs Spectrum/ZX 2.50 ATRIX PRINTERS CON117 S pin DIN to 2 x 3.5mm + 1 x 2.5mm 1/plug Dragon 2.50 RX80 Epson RX80 100cps matrix printer £204.00 Parallel printer cables RX80F/f Epson RX80F/T 100 cps matrix printer friction or tractor feed £231.00 FX80 Epson FX80 150cps matrix printer £328.50 CON130 36 way plug to 36 way plug (2M) Sirius/Apricot 18.00 MT8OSP Mannesmann Tally MT80 matrix printer friction or tractor feed CON131 36 way plug to 36 way plug (5M) Sirius/Apricot 26.50 with film ribbon and tear off facility £209.00 CON132 36 way plug to 36 way socket (2M) 18.00 CON133 36 way plug to 36 way socket (5M) 26.50 EUER QUALITY PRINTERS CON144 36 way plug to 25 way male D type (2M) IBM/TI PC 19.00 HR5 Brother HR5 Thermal printer A/C mains or battery £115.00 CON145 36 way plug to 25 way male D type (5M) IBM/TI PC 27.50 HR15 Brother HR15 Daisy wheel printer (13cps) £326.00 CONI 34 36 way plug to 25 way male D type (2M) RML/Apple 19.00 HR25 Brother HR25 Daisy wheel printer (23cps) £550.00 CON135 36 way plug to 25 way Male D type (5M) RML/Apple 27.50 UCHIDA Uchida DWX305 Daisy wheel printer (20cps) £227.00 CON142 36 way plug to 20 way IDC socket (2M) Dragon 13.95 CON139 36 way plug to 26 way IDC socket (2M) BBC 9.95 RINTER SUPPLIES CON140 36 way plug to 26 way IDC socket (5M) BBC 22.95 11241P160 11x9) 1 part CON141 36 way plug to 34 way card edge (2M) TRS80 Lev.1 18.50 plain listing paper (2,000) £11.25 11241P2C1 CON143 36 way plug to 34 way IDC socket (2M) TR580 Lev. 2/ 11x9) 2 part (otc) plain listing paper (1,0001 £14.00 11241P3C1 11 x9) 3 part (otc) Memotech 10.95 plain listing paper (700) £16.25 11370R160 11 x14 1 part ruled listing paper (2,000) £13.50 RS232 Cables 11370R2NC 11 x14 2 part (ncr) ruled listing paper (1,000) £22.50 11370R2C1 11 x14 2 part (otc) ruled listing paper (1,000) £15.00 CON106 25 way male D 5 type to pin DIN BBC 5.85 12235P160S 12x9) 1 part plain listing paper with side perfs. (2,000) £12.00 CON128 'Universal' RS232 cable (pins 1-8, 20 connected HR1R Brother HR1 ribbon £2.20 and 20 jumpered as required) 2M 15.95 RIB119 Diablo Hytype II Multistrike film ribbon £1.75 CON164 'Universal' RS232 cable as above but SM 20.95 GP205 Diablo Hytype II fabric ribbon £2.50 CON120 25 way male to male 1-25 connected (2M) 16.95 MX80 Epson MX80, RX80, FX80, fabric ribbon £3.00 CON121 25 way male to male 1 -25 -connected (5M) 22.50 MT80 Mannesmann Tally MT80 film ribbon £6.50 CON122 25 way male to male 1-25 connected (10M) 32.50 RIB117 Uchida DWX305 multistrike film ribbon £2.75 CON123 25 way male to male 1-25 connected (30M) 68.00 HRSR Brother HR5 ribbon £2.20 CONI24 25 way male to female 1-25 connected (2M) 15.45 HR15R Brother HR15 multistrike ribbon £4.00 CON125 25 way male to female 1-25 connected (5M) 21.00 HR25R Brother HR25 multistrike ribbon £4.00 CON126 25 way male to female 1-25 connected (10M) 31.00 Brother daisy wheels £14.00 CON127 25 way male to female 1-25 connected (30M) 66.50 Uchida/Oume daisywheels £4.00 CON129 25 way male to 9 way male Spectrum 15.95 LAB089361C 3)x 1.7/16 Labels 1 wide (12,000) CON162 - £20.00 25 way male to 9 way male 1 Mackintosh 15.95 LAB089361S 3) 7/16 Labels 1 wide (2,000) £13.00 CON 163 - 25 way male to 5 pin DIN RML 480Z 14.95 LAB070363F 2( 1.7/16 Labels - 3 wide (1/10") (2,000) £8.00 CIRCLE 60 FOR FURTHER DETAILS.

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 59

www.americanradiohistory.com VI continued from page 57

Abacus Electronics Ace Mailtronix Active Electronics Add-on Devices Aeromel International Altek Microcomponents Am bar Components Anglia Components Aries Electronics Arrow Electronics Aviquipo of Britain Barlec-Richfield Barrie Electronics Beta Devices Bi -oak Semicond Bosledge Campbell Collins Cirkit Wide range o popular semiconductors Consort Electronics Curzon Electronics DTV Group D.W. Electronics Doge Eurosem Dialogue Distribution Distributed Technoloav Electronic Resources Electrovalue Farnell G.E. Electronics Gain Electronics Gothic Crellon Greenweld Wide range of popular semiconductors Harmsworth Townley Hawke Electronics Hnwnt Electronics HB Electronics Hero Electronics Hi -Tek Distribution House of Power Hunter Hy - Comp Impulse Electronics JATA (Electronics) Jermyn Distribution L.S.W. Components Langrex Supplies MCP Electronics MDL Components Macro -Marketing Maplin Wide range of popular semiconductors Marco Trading Wide range of popular semiconductors MEDL Distribution Memec Merlin Electronics Microloa Micromark Electronics MS Components Wide range of popular semiconductors McLelland Electronics Newtec Distribution Norsem Noweco Phab Electronics Philips Service Polar Electronics Pronto Quarndon Rostra Electronics Regisbrook S.E.M.E. Semelab Semi Components Semicomps Semicond. Specialists Semicond Supplies Intl. Solid State Scientific STC Electronic Steatite Swift Sasco Thame Components Thorp Electronic Today Electronics Trident Microsystems Verospeed Wide range of popular semiconductors VSI Electronics (UK) Watford Electronics Wide range of popular semiconductors

www.americanradiohistory.com -o C b. - c } - _ó d . H á E d c Ñ d C lñ ydj H c hi- 7 v. 0 Y In d d d ,! 1 c o _, C oO c c c v E U Y- C x Y d d L C i c o o N x 0 C Y ÿ d Q o Cp o 7 i C W c Ñ' > 1 i i o a V E o ÿ ú ÿ Y T .n E Ol i . .V ` + c U B ío.l ¡, d ÿ L c ó in Q :._. 1n c c É É E 'A' 1 O O r_4_,>. g +- ti W o n G o d 0 l7 O O E d d d W a_ uÓ p á ?. Q .-. d ó o 'c o d._ o ñ l o d an f Y zz z000aaa aCV1 Nanean l9412-1i2). iñ+iñiñinnininninñ in 1-H1--1-=»3c Xz Abacus Electronics Ace Mailtronix Active Electronics Add-on Devices Aeromel International Altek Microcomponents Am bar Components Anglia Components Aries Electronics Arrow Electronics Aviquipo of Britain Barlec-Richfield Barrie Electronics Beta Devices Bi-pak Semicond Bosledge Campbell Collins Cirkit Consort Electronics Curzon Electronics DTV Group D.W. Electronics ()age Eurosem Dialogue Distribution Distributed Technology Electronic Resources Electrovalue Farnell G.E. Electronics Gain Electronics Gothic Crellon Greenweld Harmsworth Townley Hawke Electronics Hawnt Electronics HB Electronics Hero Electronics Hi -Tek Distribution House of Power Hunter Hy- Comp Impulse Electronics JATA (Electronics) Jermyn Distribution L.S.W. Components Langrex Supplies MCP Electronics MDL Components Macro -Marketing Mapl in Marco Trading MEDL Distribution Memec Merlin Electronics Microlog Micromark Electronics MS Components McLelland Electronics Newtec Distribution Norsem Noweco Phab Electronics Philips Service Polar Electronics Pronto Quarndon Rastra Electronics Regisbrook S.E.M.E. Semelab Semi Components Semicomps Semicond. Specialists Semicond Supplies Intl. Solid State Scientific STC Electronic Steatite Swift Sasco Thame Components Thorp Electronic Today Electronics Trident Microsystems Verospeed VSI Electronics (UK) Watford Electronics

www.americanradiohistory.com BECKMANATE DM73 facility C U' T Touch Hold' all functions. a measurement. Auto -ranging on to freeze for 12 ranges bleeper when Provides - or DC Continuity Probe Type voltages up to 500VAC anort detected. Miniature M altimeter with 0.5 ó VDC accuracy. CAVI72 CIRCUTP/UME £45.50 _vn,_ D8GITAL & pp) (incl VAT METER e2, delivery Allow 14 days aEA From ola 9eTM%+3.... ACTUAL SIZE H -SQUARED ELECTRONICS LTD Garden House, 25 Bedford Road, crName Padless Tel: (0462) 81515 Telex: 826052 - ' peas 5 sa ee c0Se

CIRCLE 55 FOR FURTHER 1)E'l'AILS. HOME CONTROL BT STYLE PHONE INVERTERS TRANSFORMERS EX -STOCK 12/24V DC -240V AC CENTRE CONNECTORS MAINS ISOLATORS 50/25V or 25-0-25V 30/158 or 15-0-158 100W £65.15 Volts Pri/Sec 120V x 2 2x258 Ta) Secs Volto 2x158 Tap Sec. 250W £170.42 This kit enables you to control up to 16 VA Price P&P available 5, 7, 8, 10, 13, available 3, 4, 5, 6 8, 9, 500W £196.19 different appliances by means of coded Line Jack Units 30 or 20 5.82 1.60 15, 17, 20, 25, 30, 33, 40, 10, 12, 15, 18, 20.24, 1000W £396.72 pulses in the mains wiring which may be `+' ! !- Master Unit Ifirst 60 9.49 1.80 20-0-20 or 25-0-25V 15-0-15V £779.90 decoded by special receivers anywhere in line unit) has bell 30V Price 100 11.08 2.00 50V 25V Price P&P 15V PAP 4000W2000W £ 1160.00 the house. The transmitter may be con- capacitor and 0.5A 1 3.19 1.20 200 15.69 2.25 0.5 1 4.13 1.40 trolled manually or by the computer inter- VOLTAGE surge arrester 1 4.32 1.40 CONSTANT 250 18.97 2.64 1 2 5.03 1.51 2 face enabling your favourite micro to TRANSFORMER 1% Flush or surface mounting. Screw con 350 23.47 2.70 2 4 8.69 1.84 2 A 4 6.99 1.60 make your coffee in the morning, switch Spike -tree stable mains nectars. 500 29.23 2.95 3 A 6 10.36 1.90 3 M 6 8.10 1.85 lights anywhere in the house, or your 250VA £172.40 Master Iflushl 1960 1101 £3.00 750 41.28 3.70 4M 8 14.10 2.12 4P 8 9.67 1.90 in your bedroom. Just £196.69 electric blanket Master (surface) 1121 6 P 12 18.01 2.20 5 S 10 11.95 2.00 500VA 1960 f3.00 1000 53.00 4.00 think of the possibilities - and no wiring! 12 13.52 2.00 1KVA £338.40 Master (mini surface) 1960 1131 £3.00 1500 68.37 4.70 8 16 24.52 2.70 6 This kit comprises a transmitter with pre 2KVA £594.50 Secondary Iflushl (960 1141 £2.65 2000 8227 5.10 10 20 30.23 3.00 8 16 18.10 2.26 drilled box and two receivers. 10 3KVA £957.73 Secondary Isurfacel 1960 1 1 61 f 2.65 3000 115.35 OA 12 24 36.18 3.20 20 20.88 2.26 XK112 £42.00 12 24 26.60 2.50 4KVA £1266.00 Secondary (mini surf) 1960 11 71 E3.00 6000 203.65 OA 60/30V or 30-0-30V 30 26.60 Additional Receivers 0 3.00 5KVA £1531.00 Dual outlet adaptor 1960 1 181 £4.20 115 or 240V sec only. Tap XK111 £10.00 Pri 2x12011. 2408 20 40 35.64 4.83 6KVA £1743.00 4 -way line cord -- with plug to spade ter 400/440V ISOLATORS Secs. Volts available 7.5KVA £2073.00 urinals 1960 1201 £2.00 6. 8, 10, 12, 16, 18, 400/440 to 200/240V CT 105, 115, 220, 230, 240V 10KVA £3347.00 4 -way line cord 1960 1301 £0.20 per m VA Price P&P 20, 24, 30. 36, 40, 48, 60, For step-up or down MEGGER5 60 9.50 1.80 24-0-24 or 30-0-30V. VA Price P&P AVOs & 100 11.08 2.00 60V 30V Price P&P 80 4.84 1.40 8Mk6(Iatesl) L138.70 200 15.68 2.25 MICROPROCESSOR 0.5 1 4.70 1.50 150 6.48 1.60 DA211 LCD £68.40 250 18.97 2.40 1 2 7.15 1.50 350 11.84 2.00 DA200V £72.80 TIMER KIT 350 23.47 2.70 2 4 9.20 1.90 500 13.30 2.24 DA116 LCD. £154.50 A ELECTRONIC 500 29.23 2.95 3 6 13.31 2.00 1000 24.14 2.80 DA117 AUTO £157.00 LOCK KIT 4.00 Designed to con - 1000 52.98 4 M B 15.15 2.20 1500 28.17 320 Megger Gen £116.40 trol 4 2000 82.27 5 00 5 10 19.16 2.20 2000 42.14 4.00 Batt Megger (85.50 With hundreds of uses indoors, garages, outputs S independently 3000 115.37 OA 6 12 21.86 2.65 3000 71.64 4A0 car anti -theft devices, electronic equip- P&P VAT 15% switching 6000 228.75 OA 8 16 30.72 3.00 5000 108.30 OA £2 ment, etc. Only the correct easily on and 10 20 35.76 330 CASED AUTOS V.W. MODEM PROJECT changed four -digit code will open it! Re- eff at preset times 24/12V or 12-0-12V 12 24 41.22 3.50 240V to 115V USA skis. Transformers T1. T2 quires a 5-15V DC supply. Output over a 7 -day cycle. 2 x 12V Secs. Pri. 240V VA Price P&P £5.70 inc VAT, P&P 750mA. Fits into standard electrical wall LED dis- 12V 24V Price P&P MINIATURES box. play of time and day, easily programmed 20 7.21 1.50 METAL OXIDE '4W 0.3A .15 2.41 .90 Sec V Amp Pri P&P 80 9.35 1.60 Complete kit )except front panel) via 20 -way keyboard. Ideal for central 5% RESISTORS f1/100 1 5 3.19 1.20 3-0-3 .2A 3.11 90 150 12.10 1.90 XK101 £11.50 heating control (including different 12, 20, 33, 47, 75, 390, 430, 2 1 4.25 1.20 6x2 lAx2 3.45 1.20 250 14.73 2.00 Electric Lock Mechanism for use with switching times for weekends). Battery 4 2 4.91 1.60 510£1, 560, 1k, 1k1, 1k3, existing locks and the 9-0-9 1 2.59 .90 500 24.14 2.20 door above kit. backup circuit. Includes box. 6 3 7.69 1.60 1k6, 1k8, 2k, 3k, 3k9, 15k, (Requires relay.) 12V AC/DC coil. 9x2 .33x2 2.41 .90 1000 33.74 2.80 1 8 time settings. 16k, 24k, 27k, 39k, 56k, 8 A 4 8.98 1.60 8,9x2 5x2 3.36 1.20 2000 60.47 4.50 (701 1501 £1 4,95 10 5 9.82 1.80 82k, 100k, 110k, 120k, M 8.9x2 1Ax2 417 1.40 EDUCATIONAL METERS CT6000K E39 00 1.90 130k, 150k, 200k, 220k, 12 p 6 10.89 15x2 .2Ax2 2.41 .90 Front linger screw TOP QUALITY ... TOP SERVICE 270k, 300k. P&P 20p. XK114. Relay Kit for CT6000 '16 s 8 12.97 2.12 12-0-12 05 3.11 90 terminals 78xg8mm PRICES! BOTTOM includes PCB, connectors and 20 10 17.46 2.44 20x2 .3x2 3.39 1.20 0-10A BRIDGE RECTIFIERS 21.69 2.64 one relay. Will accept up to 4 30 15 20x2 .15x2 1.50 .50 0-2A £3.98each 400V1A .32 60 30 44.45 OA .45 relays. 341240V c/o contacts £3.90 20,12,0 0-30V+ .50 p&p 200V 2A 83 41 51.20 4.50 £2.60 12,20 .9 4.13 1.30 100V 35A 701 15% VAT TO 115 Additional Relays E1.65 15,20-2 1Ax2 5.60 1.60 PLEASE ADO 100V 50A £3.20 96/48V. Pri 2 x 120V ALL ITEMS AFTER PAP 15,27x2.5x2 4.83 1.40 500V 12.5A £3.40 Secs 2 x 36/48V 15,27x21Ax"2 1.30 t.60 EALING ELECTRONICS NLIR,,, 73/96- 3640V Prise P&P 0-7 5-15V 0-5A2.53 .90 ARRIE ELECTRONICS LTD RNLAR Ro 0.5A 1 5.37 1.20 0-7.5-15V 4A 6.901.40 11-13 Boston Road uxeRloGc RoAO 2 A 4 14.69 2.20 0-27V 1A 1.50 .50 nit 211, Stratford Workshops London W7 3SJ 3 M 6 17.79 2.40 9-0-9V 1 A 2.20 .60 urford Road, London E15 2SP ORDERS ENQUIRIES 5 p 10 32.23 3.20 13-0-13V .15A 12V 1M 01-567 8910 01-579 9794 6 12 40.36 3.50 el: 01-555 0228 (3 lines) s 1.5040 01-579 2842 TECHNICAL AFTER 3pm 8 16 44.03 3 75 WW -6 T 1 CIRCLE 8 FOR FURTHER DETAILS. CIRCLE 54 FOR FURTHER DETAILS. ELECTRONICS C.A.D. et, MITSUBISHI "ANALYSER"

PERFORMANCE ANALYSIS of LINEAR CIRCUITS using the BBC MODEL B AND MG F-1400 GaAs FETs SINCLAIR SPECTRUM 48K MICRO'S. Simulates Resistors, Capacitors, Inductors, Transformers, Bipolar and Field effect Transistors, and MG F-1402 Operational Amplifiers in any circuit configuration. MGF-1412 FROM STOCK Performs FREQUENCY RESPONSE ANALYSIS on Circuits with up to 16 Nodes and 60 Components, for Phase and Gain/Loss, Input Impedance and Output Impedance. Ideal for the anaysis of ACT IVE and PASSIVE FILTERS, AUDIO, WIDEBAND and R.F. Aspen Electronics Limited AMPLIFIERS, LINEAR INTEGRATED CIRCUITS etc., etc. ANALYSER' can greatly reduce or Been eliminate the need to breadboard new designs. INDUSTRIAL AND UNIVERSITY R&D DEPARTMENTS WORLD WIDE. UK representative for Mitsubishi Electric USED BY LOW COST... VERY EASY TO USE. Prices from £20.00 2/3 Kildare Close, Eastcote, Ruislip For further details write or phone NUMBER ONE SYSTEMS Middlesex HA4 9UR DEPARTMENT W W 9A CROWN STREET, ST IVES Tel: 01-868 1188 Tlx: 8812727 HUNTINGDON CAMBS. UK, PE 17 4EB TEL. 0480 61778 TELEX: 32339 CIRCLE 50 FOR FURTHER DETAILS. CIRCLE 39 FOR FURTHER DE'T'AILS. 62 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com B. BAMBER ELECTRONICS

Lot No Description Sty Price Price Lot No Description Sty Price Price Lot No Description Oty Price Price Each Each Each Each Each Each As Seen Tested As Seen Tested As Seen Tested 151 Rank Xerox 1385 Photocopier 251 Marconi R.C. Oscillater. Type 296 AIM Pulse Generator...... £40 Camera with Spares & Service TF1101.... £40 £120 297 Marconi Universal Bridge, Type Manuals. (This is the original Xerox 252 Pye UHF Signal Generator. Type TF868A, 2 £75

machine 1 £500 TFSGSU - £100 298 3pH Variacs, 6 amp. 3 £60 152 Tektronix Plug -Ins, Type G 19 £15 £20 252 Pye UHF Signal Generator, Type 299 General Radio Unit Oscillator. Type 153 Tektronix Plug -Ins, Type L. ., 15 £15 £20 TFSGiU - £100 12090 3 040 154 Ditto, Type D £15 £20 253 Marconi FM/AM Modulation Meter. 300 Sanders Oscillator. Type CLC 2- 155 Dieo, Type E. £15 £20 Type -F2300...... £185 4GHz. £90 156 Ditto, Type O. £20 £60 254 Marconi Delay Generator. Type 301 Solartron Recorder Drive Unit, type 157 Dino, Type k. £10 f20 TF1415_ - £85 0295. £20 158 Ditto. Type Z £10 f20 255 Marconi R.F. Power Meter, Type 302 Rohde & Schwarz Power Test 159 Oleo, Type W 010 0120E 1 - £65 Adaptor, Type BN4 13116 £50 160 Type Ditto. 82.. £15 £30 256 Marconi Valve Voltmeter, Type 303 R. 8 S. Power Signal Generator, 161 Type Ditto. 80... £15 £20 TF10z1C. 1 ' £20 £60 0.1MHz, Type BN410X1. 0125 162 Tektronix Plug -In Extensions £10 257 Pye S68 Transmitter. Type S58130. 1 £150 304 R. 8 S. Selektomat Type USWV 163 Tektronix Plug -In. Type N_ £20 £40 258 Hewlett Packard Sweep Oscillator. 0615221. 050 164 Ditto, Type ISI. .. £30 £60 Type 3920 1 £200 305 Ferranti Video Terminal Type 165 Type IA2.. £40 Ditto, - 259 Airmec Oscillator, Type 858... . 1 £40 WDM2000 £40 166 Ditto, Type IA1...... - £40 260 MESL Sweep Signal Generator, 1- 306 Coutant Power Unit 24V7Vv4V. .. 025

167 Tektronix Low Level Preamplifier, 1 20He 0180 307 Trendata Data Test Set. No.5 . £120 Type FM122 r £20 £30 261 Comark Time Scale Generator, Type 308 Rohde 8 Schwarz Standard Signal 168 Tektronix Oscilloscope, Type 585A 1401...... 1 £30 - Generator. Type BEM 1409 £120 Less Plug In 1 £70 0200 262 Marconi A.F. Power Meter. Type 309 Hewlett Packard SHF Signal 169 Type Tektronix . Oscilloscope Camera, TF897A ...... 2 £20 £60 Generator, Model 61813.. ... £120 £220 C12 3 £30 090 263 Pye \HF Signal Generator. 3 £10 030 310 Dawe Phase Meter, Type 6325. 2 020 £50 170 Tektronix Copy Type 4601. 1 Hard Unit. £100 264 Airmec Mlllivoltmeter, Type 301. . 3 £20 £60 311 Pye Deuterium Lamp Power Supply.. 5 - £40 171 Tektronix Storage Display Unit, Type 265 Ditto Type 301A.. .. 3 £30 f90 312 Solartron Digital Voltmeter. Type 611 1 £140 266 Hewlett Packard RX Meter, Type LM1420.2. 2 £20 172 Tektronix Type Oscilloscopes, 551 250W 1 £150 313 Airmec Wattmeter. Type 319A 4 £20 £40 Less Plug Ins 7 £30 £60 267 iewlett Packard 56F Signal 314 Anmec Oscillators. Type 304A 2 030 060 173 Tektronix Time Mark Generator. Type Generator, Model 6200 2 £300 315 Marconi Valve Voltmeter, Type 1806 3 £20 060 268 Teequipment Oscilloscope. Type TF1041 B_ £20 £35 174 Tektronix Time Mark Generator, Type 043. 3 £20 316 Marconi Valve Voltmeter, Type £20 £60 269 Ditto Type S32A £25 TF1300. . 3 £15 £30 175 1 Tektronix Oscilloscope, Type 647 270 Advance Signal Generator, Type C2 4 020 317 Audio Power Meter. Type TF893. Less Plug Ins .. 1 £150 271 Sclartron Pulse Generator, Type Marconi 6 £10 £20 176 Type Ditto, 555 Less Plug Ins 3 £60 £180 G0101...... 2 f25 318 Hewlett Packard Microwave Power 177 Ditto. Type 531A With Type H Plug 272 Hewlett Packard Valve Voltmeter. Meter, Model 430.C...... £10 In 0120 Type 4000.. 2 £25 - 319 General Radio Unit IF Amp.. Type 178 Ditto, Type 547 with Type 1A2 Plug 273 Marconi A,F Power Meter. Type 1216A. £10 1 £180 In...... TF2500 1 £75 320 General Radio Modular Pulse 179 Ditto. Type 581A Less Plug In. 1 £40 274 Ma coni 25MHzP Pulse Generator. Generator, Type 1395A. 020

180 Ditto. Type 5156 Complete . , 3 £100 1 - Type TF2025...... £85 321 KSM Pulse Generator. Type T18/ D.. 2 £20 181 Tektronix Programmable 275 Wandel & Golterman Filter 322 Dawe Transistor Phase Meter. Type Calculators, Type 31 16 £40 Accessory for LDE-2 £20 630A...... 2 £20 182 Tektronix Oscilloscope, Type RM45 276 Macon 100watt 7db Attenuetor, 323 Electric International VHF Less Plug Ins...... 35 £20 Type TM5280 t40 Preamplifier Model AP501R £20 183 Ditto, Type 545B.. 2 £50 277 Bradley Synthesized Digital Signal 324 Tekelec Digital Voltmeter. Typet 184 Ditto, Type Plug 5 545A Less Ins.... £40 Generator, Type 235. 1 £90 - TE3BB. .... 015 185 Ditto, Type 545 Less Plug Ins. 3 £30 278 Hewlett Packard Signal Generator, 325 Honeywell Power Line Test Set. Type 186 Marconi Signal Generators, Type Model 6060, .. £60 - PLY -1 f10 TF995A/5 23 £120 £240 279 Pye .F. Signal Generator F10 £20 326 Hewlett Packard D.C. Power Unit. 187 Ditto, Type TF9958/5 8 £200 £400 280 veo Signal Generator.. 1 £30 Model 62688 £300 188 TX Marconi & RX Output Test Set, 281 Wayne Kerr Component Bridge. Type 327 Wavetek Programmable VCG, Model Type TF1065A 21 £40 £80 CT3'S ...., ... 2 £20 £40 t55 1 £20 - 189 Marconi V,H.F. Signal Generators. 282 Ma coni Oscilloscope Less Plug In, 328 Marconi Programmbie FM/AM Type TF106413/5 33 £50 £120 . 1 Type TF2200A/1. £50 - Modulation Meter, Type TF2301A. 1 £50 190 Cosser Mains Radio, Type 358. 2 £5 283 Mercom Oscilloscope Less Probe. 329 Pye Scalamp Voltmeter. 40KV 3 £20 £60 191 Pilot £5 Mains Radio...... Type TF1331A... 1 £50 330 Pye Scalamp Galvanometer, 9 £5 £15 233 Light Source.. 3 £5 284 Hewlett Packard Wave Analyser, 331 Rohde 8 Schwarz Polyskop II. Type 234 Large Mains Isolation Transformer 6 L10 Type 302A 1 £40 - BN4245/50...... 4 £100 0200 235 Ex. Equipment Instrument Fans 240 £0.50 285 Dime True RMS Valve Voltmeter. 332 Rohde 8 Schwarz VHF Test Receiver 1 £30 236 Capacitors. 150mtd 16v 11,500 £0.05 Type 612A. 3 £20 £40 333 Dino Endgraph Type BN18531.. 71 £30 237 Sony Empty Video Tape Reels_ 33 f0.50 286 Je-rold Field Strength Meter. Type 334 Pye mV Meter, Type 539.. £20 238 Eddystone UHF Receiver. Type 7043.. £40 335 Lampkin F.M. Modulation Meter,

7705 . 1 £70 287 Marconi Signal Generator. Type Type 205A 6 £10 239 Soldermaster Desoldering Pump . . 10 £5 TF857 2 £30 336 Hewlett Packard Ddterential 240 Aim Meters, Model 7... 20 £15 £40 288 Armer Sweep Signal Generator, Voltmeter, Type 3420/8. 3 £40

241 Rectifiers. M201 . 400 .. £0,50 Type 352. 1 £30 337 Marconi 20MHz Sweep Generator, 242 Pyrometers 20 £1 Pye 289 Westminster. Low Band 24 volt, Type TF1099. 1 £50 4 14 243 Berco Rheostats. ... £2 Typo W30.. £25 - 330 Racal Frequency Meter, Type 9059, 1 £70

244 A.C. Chargers. 110V AC Input.. . 1 ctn. 110 290 Marconi White Noise Test Set. Type 356 Roband Oscilloscope. Type R050A 5 010 245 Attache Cases with Intregral Peg 050908. £200 - 357 Marconi VHF Signal Generator, Type Boards 3 £5 291 Briet 8 Kioer Microphone Ampler, TF1060. 6 £60 £120 246 Baldwin Radiological Densitometers. 2 £5 Type 2604. £50 - 358 Marconi A.M. Signal Generator. Type 247 Reyrolle Metalclad 15 amp 292 Pye pH Meter Type PW9418 £40 - TF801. 6 £40 £80 Connectors .. 4 ctn £10 293 Mtrconi Sine Squared Pulse 8 Bar 359 Radiometer FM/AM Signal 248 Wild Barfield Incinerator. t £20 Generator. Type TF2905/6M £90 - Generator, Type MS27g 8 060 £100 249 Schomandl Frequency Meter. Type 294 Marconi F.M. Signal Generator. Type 360 Elettrohome 9in. Video Monitors. 8 £25 £50 F01...... 6 £25 TF066A/1 £70 £140 361 Anmec Modulation Meter Type 250 C.R. TS Braman Type D13/47tH..... 4 05 295 E.It Pulse Generator, Type 139L8... £40 210A. '2 £40 £120

DIODES Schomandl Modulator Type MAF BN841962. .. £650 RADIOTELEPHONE EQUIPMENT Schomandl Synthesizer Type NO100M. (55406 £1200 & IN5407 Rohde B Schwarz DecadeSignal Generator 0.3- 500 MhzTypeSMOV BN41104 £1200 Pye BaseStation Type F30 AM High Band & Low Band £220 10p EACH Pye Modulation Meter 68- 510Mhz Type MM1 with manual £60 Pye Base Station F401 AM High Band £250 100 OFF £5 Marconi Universal Bridge Type TF 8688 £110 1000 OFF £30 Servemex AC Voltage Stabiliser Type AC22dOv ac 9amp C45 Pye Reporter Type MF6 AM High Band £90 Servomec AC VdltageStabdiser Type AC7240v ac 40amp £95 Pye EuropaTypeMF5FM High Band £70 60 amp Alternator & Generator Noise Filter £1.00 each. Tektronix Oscilloscope Probes Pye Europa Type MF5U UHF £70 £10 each. PYE POCKETFONE PF1 Mulland Van -cap Tuners Type ELC 2003 Ex Brand New Equip £3.50 Pye Olympic Type M201 AM High Band £65 PyeCambndge/Vanguard 18 Way Control Leads.. £4.00 Pye Olympic Type M212 UHF £65 UHF RECEIVER BNC Plugs75ohm...... 50p each Circulators 590 - 720 Mhz "14- sockets £25 Pye MotofoneType MF5AM High Band & Low Band £45 Transistors Type 2N3055 Brand New ... 4lorí1 440-470 MHz, Single Channel, int. speaker Pye M293 AM High Band £120 Transformers 30 volt m l amp ...... 01.00 and aerial. Supplied complete with Transformers 36 volt sa t b Pye M296 FM UHF £160 amp 01.00 rechargeable battery and service manual, £6 'Variacs- 2 amp. 8 amp. 15 amp. 20 amp. 25amp Phonefordelails. Pye Pocketphone PF1 Battery Charger 12 Way £10 each plus £1p.p, plus V.A.T. Loudspeakers Richard Allan Type CP12. 121n. 15ohm .. í6.0o Pye Base Station Type F9U UHF £90 10.7 Mhz SSO Xtal Filters 12.4 Khz Bandwidth) Low imp. type. Career and unwanter s deba d eject on n 40db)needs 10.69835810.70165 Brats for USB/LSBnotsupplied) Pye Base Station Type F412 UHF £200 Sieeapproa2in.alin. cl in...... £10.00 each. Pye Pocketfones Type PF2 FM High Band £80 RADIOSONDE RS21 Low Pass Filters (low imp. type). 2 to 9 Mhz. small metal encapsulation.... . 75p each. IC TestClrps . Pye BaseStation Type F460 Tx. UHF £50 Gold plated pins, 28 pin DlL and 40 pm DIL _í2.00 each. METEOROLOGICAL tin. Vidicon Scan Coils Transistor type but no details, complete with vidicon base. £6.50 PLEASE NOTE all seis ere soul - ninenerse ciarle Scews. Pack hi nut, bolts. washers, tags, sett taps etc. Mixed BA 8 Metric. Sold by Carriage on er eeuipinenl M. n,.... -,.n ease 51air0510110,,S£IS - Weight . . ... £2.00 per Kilo. 00 earn Red Sin avarldme all .. BALLOON TRANSMITTER Mains Isolation Transformers 500 VA 240 v input. 240 v CT output housed in metal box but with Water Activated Battery, contains all- l lid. .£15,00 Large Stocké of Ex -Equip. Crystals £2 each + VAT SAE for Lists. Ovoess Valve Characteristic Meter Type VCM 163 with data. weather sensors, fully solid state, £5 each Tektronix Oscilloscope Type 453 Dual-Trace50 Mhz . ... £595 plus £1p.p. V.A.T.

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Access 5 STATION ROAD, LITTLEPORT, CAMBS CB6 10E .tsL PHONE: ELY (0353) 860185 I{ll\ ri with:1CCCSS

CIRCLE 22 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD DECEMBER 1984 63

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that "In mechanical systems using synchronizing signal of the D.C. SUPPLIES one rotating member, the Baird -BBC 30 -line service positioning of the lines is a fixed was derived from a black line at I got lost in Dr Smith's = 1 NAAf, factor using one rotating the top of the picture, scanning generally excellent article on member, the positioning of the being carried out from the "D.c supplies from a.c. which I would be interested to lines is a fixed factor in relation bottom right hand corner of the sources", October issue, when I see established. to the rotating disc or mirror vertical upright picture, the got to the Appendix, after the Finally. I deplore your lapse drum that produces the number spot moving vertically upwards, first equation on page 68. That from the excellent practice, so of pictures per second. So long covering the picture area from equation indeed applies for a long maintained after other as the device rotates at the right to left, finishing in the top square wave of voltage balanced once -fine journals departed right speed the number and left hand corner. The lines at about zero volts. from it, of maintaining a positions of the lines is bound the centre of the picture were "If you drive the winding with sensible separation between to be correct. Centering the also more narrow than those at a unidirectional pulse train..." advertising and the rest. I have picture or avoiding it being split the outside edge to improve starts the next paragraph; ... Of for years pursued the is bound to be correct. centre picture definition. voltage one assumes pro tern. advertisements thoroughly in Centering the picture or Various accounts emphasise The core will then certainly "be WW when it has suited me: I avoiding it being split vertically the need for a strong pulse into for how long magnetized in one direction am now wondering is all that has to be adjusted - the sync. coils for a steady I will have the patience to avoid only" in the sense that each as there are 121/2 pictures per picture. However with the Baird application of unidirectional the d...d things when I want to second, each with 30 lines disc scanner receiver where voltage will drive the flux in the read the rest. (with the black spacer at the most circuits show the sync. same direction, in accordance R.S. Taunton top), the frequency of the coils connected in series with with Faraday's Law cited on the Crowborough synchronizing pulses will be 375 the neon picture lamp, this East Surrey previous page. But this per second - the 'phonic would result in a negative immediately followed with a wheel' synchronizer will have picture as well as requiring a reference to Fig. A3 and a peak BAIRD 30 teeth with the distance high h.t. voltage of over 200 value of flux which seems to be between each tooth being volts, usually derived from followed by a reversal of flux I was very surprised to read in approx twice the width of each batteries. To get a positive change. What voltage accounts the June issue of Electronics & tooth". picture with strong sync. for this? (There can in practice Wireless World on page 15 and 2. Television for the Amateur pulses, the circuit on page 106 be several answers but they all 16 under the heading Constructor by H.J. Barton of the 'Book of Practical seem to introduce factors which 'Communications Commentary' Chapple Publisher: Sir Isaac Television' would have to be have not been included within - sub -title 'Baird in history' Pitman & Sons, London. 2nd used with the sync. signals via the stated problem with its that,"Baird's low definition Edtn 1934 the transformer phased for unidirectional pulse (voltage) television was barely ... true Chapter IX 'Making Vision positive -going with a positive train.) television ... since, even in its apparatus', page 194, "- using picture from the negative If the unidirectional pulses final broadcast form, it the 'tuned' synchronising signal, the black sync. line at are of current there is no contained no real sync. transformer to resonate at 375 the top of the picture giving perceivable relevance of flux signals". It does of course c/s to give a strong sync. -" maximum transmitter output. considerations at all unless by depend upon what meaning one Author's note: This would also An example, however, of the some very indirect route attaches to those last four enable the sync. signals to be good sync. results that could be involving permeability. words. connected in the correct phase, obtained from a disc -scanning In my experience a circuit For two years I have been see later explanation. receiver is given on page 386 of diagram always helps, even in compiling a chronological Television Engineering by the September 1934 issue of the simplest cases. In Fig. A3 history of early mechanical J.C. Wilson Publisher: Sir Issac 'Television' in which the 'Disc there are two graphs for i, the television taken from the pages Pitman & Sons, London. 1937. Kit' being supplied by British lower of them labelled of technical journals and books Chapter IX 'Synchronizing', Television Supplies Ltd., of "decrease in magnetizing of the period 1870 to 1937, pages 340/1, Figs 206, 7&8 Bush House is being reviewed. current". Is this shown including our own Wireless 'Toothed wheel mechanical The last paragraph states 'the separately because it is World, Television (& Short synchronizing' - moreover the synchronizing gear was effective supposed to be in a different Wave World), The Electrician impulses must be positive in the in holding the picture steady for winding? and many others. coils of the synchronizer, they long periods. We have every Below A3 a paragraph starts To avoid making this account must give rise to an increase in confidence in recommending "The usual procedure is to take too long I will confine myself the current passing through the this kit receiver'. In this version the ratio of the mean values of mainly to statements found in coils and not a decrease. Circuit the phonic wheel assembly was flux...". Looking at Fig.A4 and text books of the early 1930's 207 shows how this can be mounted on the scanning disc wondering what two or more when the service was actually in accomplished for low definition spindle, while the driving motor values of mean flux there might operation and which show that transmissions (a transformer was fixed to the wooden be, I see rl used as if it were the the importance of the coupled circuit) - the usual baseboard at one side . ratio between the peak synchronizing signals actually resistance of the two coils in connected to the spindle by (supposedly equal) positive and transmitted at 375 Hz were well series is between 700 to 1000 pulleys and a circular form negative excursions of flux appreciated and were well ohms with an inductance of rubber belt to reduce 'hunting'. about the (single unique) -mean, within the capabilities of all some 3 to 4H (page 342). Much correspondence and at last in the botton part pf Fig. main BBC m.w. broadcast This book is notable also for technical notes appeared in the A4. But the range of flux transmitters as explained in the the completeness of the various various technical magazines change (whether in time T/2 or extract from the 1st book. chapter references and for under the heading 'Reversing not depending on unstated 1. Book of Practical Appendix VII 'Table of early Negative Pictures' but assumptions) is then 21lwhere Television edited by G.V. t.v. disclosures' which I have regretfully almost no attention is the mean flux. But by this Dowding Publisher: found of great assistance. was given to the importance of time the meaning of the Amalgamated Press, Farringdon In the case of the earlier strong positive -going pulses in symbols is starting to become St., E.C.1. 1935 Chapter 9, more 'popular' books, it does the phonic wheel synchronizer obscure. Certainly it is a matter 'Synchronizing a mechanical not seem to have been coils by correct phasing from a requiring proof, to my mind, viewer', p.106: appreciated that the postive picture signal. A good 64 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

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example of a note under the Wireless World to publish a which is right; they like to work from' and `considered with above heading is at the bottom series of articles on the new on its rough spots and improve reference to -"the railway of page 144 of the April 1934 physics. it rather than throwing out the embankment' which occur in issue of 'Television'. Wireless World to issue baby. Einstein's exposition. Einstein The apparent general failure printed self-adhesive labels for One thing that I will not do is asserted, not that M' was to appreciate the above affixing to the above folders. to give away my own views on hastening away from or toward probably accounted for the poor Each article to be classified by the correctness of relativity, so a beam of light in any absolute overall reputation of the Baird the Decimal Bibliographical don't try to read between the sense, but only that he was disc -scanner receiver. The later System. lines! What I do want people to doing so relative to the mirror drum versions were Introductory pages to be do is to think about what kind observers stationary with much superior and I can available giving a list of of evidence or arguments are respect to the embankment. personally remember the whole physicists in sympathy with the appropriate for use with a Consequently light from the 30 or so minute transmission London School whether theory whose applications are in strike at B would certainly (including the '8 Step Sisters') contributors or not. the frontier districts of science. reach him before it reached M, without any loss of Every so often Wireless World It has been failure to do this a commonsense conclusion . synchronization and this is should describe an experiment rather than anything to do with which for once special relativity confirmed by a Wireless World that should be made in order to relativity which has kept your allows to be true. Dr Murray's review of the Bush radio, Baird test theories put forward by columns busy. `routine reminder that the mirror drum receiver in the contributors. J.G.D. Pratt velocity of light from a moving Sept. 15th 1933 issue, pages A.H. Winterflood West Horsley source - a relatively moving 237/8, where favourable Muswell Hill Leatherhead source - has never been comment was made to the London N10 Surrey measured' has now been steadiness of the picture. "The overtaken by events. The Open synchronizing is really good and University program `Maths; during a half hour transmission I must have written my letter In his article 'The Roots of Space -Time Geometry' the apparatus often carries (July) badly, because I was Relativity' in the May issue Dr broadcast on BBC2 on June 2nd through without going out of concerned with what kind of Scott Murray claims to reveal a described a measurement sync. even once - - - - the factors would lead us to crucial mistake in Einstein's carried out in Paris of the lapses from sync. are approve or disapprove of a early (1905) account of a velocity of light emitted by apparently due more to the theory, and not with any 'thought experiment' on the electrons travelling round a transmitter scanner than the application to specific points in failure of simultaneity in special storage ring at a speed relative receiver, for they invariably relativity. Presumably everyone relativity. He states (p.71, to the lab. of some 95% of the occur at the end of an item agrees that special relativity co1.3) that "at the instant when speed of light. The ring consists when the curtain falls to the works, in the sense that it gives the flashes occur the position of of alternate straight and curved studio. Apparently this a good quantitative description M' coincides with that of M". segments, the electrons being interrupts the sync. impulses". of phenomena studied in With this phrase and in what bent to follow the latter by F. Poperwell mechanics. (The first cyclotrons follows he assumes that if M, magnetic fields. In the curved Totteridge only worked with low energy the observer on the segments, because of their London particles because they assumed embankment, interprets the enforced centripetal Newtonian mechanics to be lightning strikes at A and B as acceleration, the electrons accurate; only after they were occurring at the same instant, generate electromagnetic re -designed with relativistic i.e. as being simultaneous, then radiation. By sending bunches RELATIVITY mechanics would they work so will the observer on the of electrons round the the with higher energies.) So if train, M'. By so doing he storage ring one can cause this It was delightful to read that the theory appears to be invalidates the whole of his radiation to be generated in Professor McCausland has nonsensical in some particular subsequent discussion. In fact if pulses, and the velocity of the finally come down in favour of application, what are we to M interprets the two strikes as pulses can be measured in the the anti -relativists. His polite, make of it all? being simultaneous M' will laboratory, in any chosen `bending -over -backwards' One guiding principle is interpret the strike at B, toward direction relative to the motion approach to see the relativists "don't throw the baby out with which point he is travelling, as of the electrons, using suitable point of view must have been the bath water"; anyone who occurring before that at A. It is collimation to ensure that the quite frustrating. I congratulate does that is not a fit person to a safe bet that hardly any of the radiation observed comes from him for his succinct conclusion bath the baby. Do you 'scientifically educated people the right segment. Within that Special Relativity is now remember the bell ringers and (who) harbour niggling doubts experimental error that velocity too suspect to be regarded as a the clock maker? Look at all about it (special relativity) have was found to be equal to the tenable theory. relativity's successes as well as really grasped what the failure velocity of light. Even natural It is also delightful to read Dr its difficulties and then decide if of simultaneity entails. The philosophers are not entitled to Murray's views and comments there is something worthwhile mutually contradictory nature of ignore the evidence of on one of Einstein's mistakes and important in it. Einstein the various criticisms of special experiment. concerning Relativity theory. won just fame because he wrote relativity, which Dr Murray C.F. Coleman Can I now enter the field with the first worlds on relativity, himself remarks upon, reflects Grove, Nr Wantage a suggestion? Since Wireless not the last words; as most of the different points in the Oxfordshire World has aggregated an elite its applications are at the criticisms at which the band of contributors and letter frontiers of science the theory assumption of universal writers who are dissatisfied has developed since his day. simultaneity is slipped in, a FUNDAMENTALS with contemporary physics, The helpful thing to do is to process of which Dr Murray's OF ENERGY why not harness such dissident show how its flaws can be analysis of Einstein's crucial energy? Such a team could re- overcome, not merely to mistake' provides a typical TRANSFER shape the physics of the world! snigger and do nothing example. I suggest this harnessing constructive. Rightly or Some hypnotist must have It is always refreshing to see a could be done by a scheme wrongly, scientists are been at work on him to account contribution from Ivor Catt even (produced under the auspices of impressed by a theory which (in for the way he fails to register if I do not wholly concur with Wireless World) as follows its growing stages) does a lot the key provisos 'as judged his conclusions. I am well aware ELECTRONICS & WIRELESS WORLD DECEMBER 1984 65

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of Heaviside's views that that the definition does not persuade his students that electromagnetic energy leaves a specify that the two conductors nothing traverses a transmission source and enters a load should be the go and return of a line in the TEM mode sideways, sideways, and he gives an single circuit. They could when- in all quarters, they see example of a source in London perhaps be the two go "authoritative" statements to connected by a telegraph wire to conductors of a circuit with a the contrary? a receiver in Edinburgh. Some distant common return. Apart Chris Parton of the energy from London from the added complexity due Bell College of Technology travels far out into space before to the third conductor the Hamilton converging on the receiver, , but problem is the same whether Scotland unfortunately I have not been the currents in the specified able to find in Heaviside's conductors flow in the same or Electromagnetic Papers any opposite senses. The twin - account of how the energy in beam c.r.o. is an example of distant space knows that it is two parallel conductors carrying Mr Catt's article (September time to start the descent for current in the same direction. It 1984) treads some very shaky Edinburgh. However, this is a can be easily shown for this ground: I consider many of his difficult matter and it is not case that for relatively low statements to be rather surprising that the story is anode voltages the beams repel questionable but I think I can incomplete. What is much more each other electrostatically. As lay the rest the so called 'Catt difficult to accept is why we the anode voltage is increased Anomaly'. should in our theory stumble on the magnetic attraction of the If I understand Mr Catt the relatively simple matter of a beams becomes greater and correctly he is unwilling to parallel -wire transmission line. would exactly neutralise the accept that a charge pulse can The National Physical that if a line has Zo = 100Q repulsion if the electrons in the travel down a transmission line Laboratory defines the SI unit of then to establish a current of lA beams could accelerate to the at a speed greater than the electric current as "The ampere in the line we need a supply of speed of light and there, as in ,speed of light local of the is that constant current which, 100V and the electrostatic the case of inifite parallel copper of the conductors. if maintained in two straight attraction because of that conductors, the nett force would In fact, the speed of light in parallel conductors of infinite cannot be ignored. be zero. Examination questions the conductors (or, for that length, of negligible cross Forces- on the conductors of a on this part of c.r.t. science are matter, the electron drift speed section, and placed 1 metre transmission line arise from not uncommon and take the of some millimetres a minute) apart in vacuum, would produce reflections, and the principal form of "Show that, no matter has no bearing at all on the between these conductors a force characteristic of an infinite line how the beam electrons are speed of an EM pulse travelling equal to 2 X 10-' newtons per is that it is free of reflections. accelerated, the force between down the transmission line. In 1 metre of length." Now this absence of force on an beams can never become nanosecond charge does not Many text books on infinite line follows almost attractive". The short answer to have to travel 1 foot down the electricity, elementary and intuitively from the principal of that is that we can never get the wire: all that is required is for a advanced, use similar wording virtual work so it is all the more electron velocity up to the drift of charges to occur at the to define the ampere and indeed surprising that the error should energy propagation velocity of leading edge of the pulse, as it the definition is not new. If we have gone undetected for so the parallel conductors. moves, so as to leave a net substitute centimetre for metre long. In an infinite line there is It is quite understandable how charge on the wire, in the wake and dyne for newton we have equal sharing of the stored the definition of the ampere of the pulse. the c.g.s. electrodynamic energy between the electric and comes to be as it is. A line of If this does not seem clear, definition of the ampere that magnetic fields associated with finite length has end effects that consider the case of a low has been used since the the line. If we increase the we do not know how to take amplitude sound pressure beginning of this century, and separation of the line into account, so what could be pulse, travelling down a pipe: during this time this piece of conductors by a small amount simpler than to remove them to the air in the pipe, behind the scientific nonsense has been for we need a force to overcome the infinity? Unfortuntely this ploy wave front travels very slowly the most part uncritically electrostatic attraction, and that leaves us with a useless line as indeed, while the pressure front accepted. can be calculated from f = dw/ far as the measurement of force travels forwards at the speed of Consider the following dx where dw is the increase in is concerned. sound. relatively short transmission stored energy and dx the In practice, the SI definition I should like to add that I lines: displacement. Likewise the makes no difference for no one consider the issue of whether In diagram (a) the line is open force associated with increasing pays any attention to it. The EM fields in a waveguide cause circuit at the distant end hence the magnetic field energy is f = ampere is standardised using an currents in the conductors, or the conductors experience a dw/dx and because of energy Ayrton-Jones current balance in vice versa, to be a meaningless, mutual electrostatic attraction. sharing equally, dw is the same which the conductors are unanswerable question: field In (b) the conductors carry a in each case, as is dx, and the arranged as circular coils and and currents are related by the current and hence mutually forces oppose each other, so not as straight lines. In the physics of the situation, one repel each other. In (c) we have there is a net resultant of zero. Ayrton-Jones balance we are does not preceed the other in a combination of electrostatic Mr Catt rightly says that dealing with equivalent lines time, and no wave or pulse attraction and electromagnetic nothing travels sideways across finite length short-circuited at travels without both. repulsion which for some value a transmission line in the TEM the far end so that all the There are a great many of R must neutralise each other. mode and that includes force. energy is stored in the magnetic statements in Mr Catt's article Not very surprisingly the Lateral forces on the conductors field and none in the electric to which I take exception, but I value of R to produce zero of a transmission line always field, so we have no problems. lack the enthusiasm to describe resultant force is the arise because of reflections that However, the definition does all the fallacies, or research his characteristic impedance of the upset the balance of electric and make a difference of those of us reference list to isolate their line, and that can be achieved magnetic energy storage in the like Mr Catt and me who have origins. by extending the line in diagram line. That is only possible with some responsiblity for educating N:C. Hawkes (a) infinitely to the right. It a line of finite length. the young in fundamentals of Abingdon seems to have been forgotten Of course it may be objected our science. How can Mr Catt Oxfordshire 66 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com PUT BBC BASIC IN CONTROL USE THE 6502 2ND PROCESSOR WITH BIG CONNECTIONS

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ELECTRONICS & WIRELESS WORLD DECEMBER 1984 67

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For details of subscriptions and the benefits The IC -M700 of membership, please contact the Membership Services Department. channels and operates in simplex or semi -duplex covering all include post and packing. Members of All items in this advertisement -to -shore, high seas telephone and ship -to -ship SSB the society are entiled to discounts on these prices. Personal callers ship may obtain goods minus postage and packing charges. channels. Independent transmit and receive programming. A heavy-duty loudspeaker provides 5 watts of To ensure delivery of books in time for Christmas your order should arrive by December 3rd. receive audio, other features include a wide range clarifier and audio activated squelch (radio remains silent unless a human voice is detected). Interference noise blanker and a heavy-duty Radio Society of Great Britain (CA4) mounting bracket are standard. The IC -M700 is a sophisticated but rugged and reliable marine transceiver. Alma House, Cranbourne Road, ICOM Potters Bar, Herts EN6 3JW Telephone: 0707 59015 Ltd ElectronicsDefence. Thanet Equipment tothe Ministry of Suppliersof Radio Communication 143 Reculver Road, Herne Bay Kent, England.Te1(02273)63859/63850. Telex 965179. CIRCLE 15 FOR FURTHER DETAILS. CIRCLE 19 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com MOBILE RADIO

by N.S. Cawthorne, Mobile radio system MIEE and techniques Topics discussed at the IEE conference recently held in York.

Efficient use of the radio spec- Mr Bellchambers went on to bring to that conference ideas for trum was the theme that ran question the wisdom of having streamlining the international through many of the papers pre- two incompatible services frequency spectrum management sented at the lEE's September operating in the same frequency process. 1984 conference in York on band in neighbouring countries, In conclusion, Mr Bellcham- "Mobile Radio Systems and as will soon be the case in Band bers wondered whether the tech- Techniques". The radio spectrum III. The UK will be using these nology of the future would enable is a natural resource of finite frequencies for new land mobile today's method of "frequency quantity, much of which is sub- radio services while the UK's con- allocation" which defines specific ject to an ever increasing demand tinental neighbours will continue frequencies, to be replaced by a from spectrum users, including to use these frequencies for tv spectrally more efficient system the land mobile radio services. transmissions. where a given service would be Mobile radio in the UK today is The planning of the interna- allocated a "band" of frequencies. going through a period of tional radio spectrum is currently The equipment itself would be changes. The two new cellular done through a programme of continuously frequency agile and networks at 90OMHz are now ITU conferences, starting with would allocate itself a frequency being installed by Racal and TSCR the administration conferences, within the given band to give opti- in a dramatic race to be first on the such as the WARC held in 1979, mum performance under the air and to be operational by early which are followed by a series of given circumstances. This was a 1985. At lower frequencies, the detail Planning conferences, direct challenge to engineers to UK's Bands I and III tv transmit- spread over a number of years. design more spectrally efficient ters are to be turned off for ever at The time taken for the implemen- systems. the end of 1984, leaving over tation of new frequency alloc- 70MHz of prime spectrum avail- ations has been up to 20 years. Cellular radio able for other services. Band III Mr Bellchambers wondered if Fig.1. Proposed Skylink (174-225MHz) has already been there was not a better way of The present phase of cellular America mobile satellite ear -marked for land mobile radio managing the spectrum interna- radio being planned or installed service for coverage of North use. tionally, that could take less time by European administrations will America from a single geo- Internationally too, mobile and be more responsive to not be compatible on a truly pan- stationary satellite using up radio is seeing many changes with changes in technology. Mr Bell - European basis. Cellular radio and down links in the upper new cellular radio network being chambers urged the delegates to users will have to wait until the u.h.f. bands. Mobile users planned or installed in several start planning now for the next next generation of cellular mobile would access the satellite countries. The choice of system WRAC in five years time, and to radio equipments are available in directly. to be used (AMPS, TACS, NMT, S-900, MATS -E etc) is still being heatedly discussed in many coun- tries. Consequently, there was no shortage of topics for the 341 del- egates from 22 countries to dis- cuss during the four days of con- 821-825 MHz ference!

Spectrum efficiency 866- 870MHz

In his opening address, Mr W.H. 821- 825 MHz Bellchambers, one of the five 821- 825 MHz Operations centre members of the Geneva -based International Frequency Regis- tration Board, made pleas for a 866-870MHz 866 -870 MHz greater awareness of both spec- trum engineering and spectrum efficiency. This should include the establishment of research posts into "frequency manage- Wire PSTN 00 ,ò f! 41óa0 or ment" at universities and more `t private network standardization on the use of fre- Mobile or portable terminal Base station quencies internationally. ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com MOBILE RADIO

the early 1990's before they can satellite over the North American permissible signal strengths from drive from one country to another continent. UK land mobile services in and still use their car radio -tele- A paper describing a proposal France. phone. for a UK land mobile communic- A large response had been Cellular radio installations in ations satellite experiment which received from industry and inter- Ireland, Hong Kong and Finland would use four satellites (3 live ested parties to the Government's were described at the conference and 1 standby) in a Molniya orbit Green Paper on the future uses of by representatives of the respec- to give 24 hours coverage was these frequencies. Mr Fisher tive administrations. presented by a team from the Uni- informed the conference that the The Irish PTT earlier this year versity of Bradford. An extended RRD would be making an scrapped plans to use a 450 MHz feasibility study has been under- announcement concerning its network and has now opted for a taken by a number of UK univer- preliminary findings at the lEE TACS network on 900MHz that sities and the Rutherford - colloquium to be held on 8th would be compatible with the Appleton laboratory. Apart from November. network currently being installed the super -synchronous, pear in the UK. shaped Molniya orbit proposed, "Refugees from Band lI" Delegates heard with interest the other major feature of the about the experience gained with study project is the proposed use The mobile radio networks run by the Hong Kong 450 MHz cellular of on -board microprocessor faci- the UK's utilities (Electricity, Gas network that operates throughout lities for signal and message and Coal) are currently operating the colony's tightly packed high- handling to maximize the effi- on frequencies just above the rise building areas. ciency of resource usage. present f.m. Band II (104-108 MHz). As the f.m. broadcast band Band III French TV channels limit is to be increased to 108 V S V s V s V V s MHz on an exclusive basis by 1 1995 at the latest, the radio networks operated by the utilities Ch 05 Ch 06 Ch 07 Ch 08 Ch 09 Ch 10 will have to be relocated. The uti-

174 180 185 190 195 200 205 210 215 220 225 lities because of the nature of the MHz services provided, need to have nationwide communications faci- lities. Units operating in one part of the country might have to be Base Tx 1 Mobile Tx 1 Mobile Tx 2 Base Tx 2 Base Tx 3 Mobile Tx 3 transfered to another to meet a particular local requirement and 174 180 185 190 195 200 205 210 215 220 225 MHz the communications facility Fig.2. UK land mobile Cellular radio users in the four needs to go with them. services sub -bands in Band Scandinavian countries using the Band III in the UK Mr C.E. Dadson of the Elec- III, planned to avoid vision NMT system on 450MHz can tricity Council speaking on behalf Mr K.P. Fisher of the Radio carriers of the new French move across borders within Scan- of the mobile radio services of the Regulatory Department of the fourth channel programme dinavia and stil have access to the nationalized power industries DTI described in detail some of Plus'. radio -telephone network. Future said that they need wide area 'Canal the technical background to the development of the NMT system mobile radio coverage in order to Band III frequency allocation will include the installation of a be able to provide communic- proposals for land mobile ser- 900 MHz network. Even though ations for essential services. The vices in the UK Government's the frequencies used may be the present proposal is that the utilit- May 1984 Green Paper on the same as other European cellular ies should relocate from their future uses of Bands I and III after networks (eg: the UK TACS sys- Band II frequencies to the new the closedown of 405 -line tv tems will also be on 900 MHz), mobile services allocations in transmissions on at the end of the different signalling proce- Band III. 1984. dures used make the systems Mr Dadson expressed fears The DTI was well aware that incompatible. that, in practice, land mobile ser- any new land mobile service on vices operating in Band III in the band III frequencies would Satellite versus cellular competition with continental have to be very carefully planned stations might be put out of ser- Papers describing possible future to avoid interference to the ser- vice for days on end because of land mobile vices from the transmissions services in North interference caused through tro- America described how coverage from neighbouring countries that posheric propagation and ducting would be available to mobile radio will continue to use band III for conditions. Coastal areas, where users in rural and remote areas the foreseeable future. operating restrictions in Band III via satellite. Areas that would In planning the future use of would be the greatest, were often band III for mobile services in never likely be covered by cellular the just those areas where the nation- radio networks because of the low UK, Mr Fisher stated that it is the alized power industries needed to user density could be served level of interference caused to have the best communications. directly by the propposed satellite continental tv viewers that is the In conclusion he asked for special land mobile network. limiting system design contraint consideration of the national Skylink Corporation of Amer- rather than the interference coverage requirements of the ica described proposal for a caused to the mobile services by their "refugees from Band II"! mobile, portable and limited fixed the overseas tv signals. Mr services network operating in two Fisher informed the delegates H.t. radio 4 MHz sectors (821-825 MHz that an agreement had been receive, 866-870 MHz transmit) drawn up with the French admin- Although the majority of the from a single geo-stationary istration setting out the highest papers related to v.h.f. u.h.f. 70 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com systems, there were two papers with 144MHz transceivers to References Pagers 1. FEE Conference Publication 238 on h.f. techniques. One by Mr N. build up a propagation map of an "Mobile Radio Systems and Techniques". Gerdes of the School of Signals area around Birmingham in order 2. HMSO Cmnd 9241, "Bands I and III" described a low-cost h.f. propa- Paging systems are also users of to determine the relative per- Consultative Document gation prediction method which the radio spectrum and as they formance of different sites for use could be run on a BBC computer. develop forward from the basic in a possible emergency commu- Comparisons between actual and "bleeper" to carriers of mes- nications operation as part of predicted propagation on differ- sages, both numeric and alpha- Raynet. Unlike professional ent h.f. paths are the subject of numeric, they bring together propagation analyses which rely continued investigation, but so radio engineering and data trans- on expensive test -gear, this ama- far there appears to be close mission technologies. Papers teur experiment relied more on correlation. The method is described recent developments in the enthusiasm of the partici- intended as a low-cost alternative the integration of pagerr receiv- pants that it did on test gear. to the prediction programs run on ers. One such paging receiver, (Although presumably the com- main-frame computers by described by a team from Philips puter required to solve the 300 bureaux. Research Laboratories had only odd complex simultaneous equ- The second papers on h.f. 12 "off -chip" components (but ations after the event in order to described an experiment being 13, including the battery!). produce the results could have carried out at the University of The POCSAG paging code orig- been classified as "expensive test York into improved design forh.f. inally devised by the UK Post gear"!). communication networks involv- Office has bow become standar- ing mobiles. The study centred dized by the CCIR for interna- The IEE's Conference on Mobile around a network of sereral inter- tional use. Radio Systems and Techniques connected h.f. base stations and came at a time of unprecedented a mobile station. The objective change and developments in the Amateur radio experiment was to increase the reliability of area of mobile radio in the UK. By communication to and from the the time that the next such con- mobile station by the interchange As with any meeting of interna- ference is held, both cellular radio of data between the base stations tional mobile radio specialists and the new Bank III mobile ser- concerning the reception of the ther was a good number of ama- vices will have been put into oper- mobile. This was described as teur radio operators among the ation and it can be expected that "geographic diversity" . As part of delegates. One of the presented there will then be more papers the study a low -power h.f. link is papers described an amateur based on actual experience and to be set up between York and radio experiment which involved less on predictive techniques that Canterbury. using a number of mobiles fitted was the case this year.

CIRCUIT IDEAS

he device, drift was +0.ö ®' in DON'T WASTE GOO r 1TDEAS Pulse -width demodulator the first 15 minutes, +0.02% We prefer circuit ideas with over the next hour and ±0.02% neat drawings and Designed as part of an optical - a stabilized supply, the only thereafter. widely -spaced typescripts, but fibre interface between a drift problems seem to be those Jim Dawson we would rather have scribbles computer and e.h.t. generator, due to temperature. After University of New South Wales on 'the back of an envelope' this pulse -width demodulator gluing a lump of aluminium to Sydney than let good ideas be wasted. uses a 723 voltage regulator Submissions are judged on and fet as a low -drift constant - 15V originality or usefulness - current sink. not excluding imaginative The 723 and fet provide a +5V modifications to existing 4.77mA reference for a 10kHz 330 circuits so these points should pulse -width demodulator. When 50 } 2k2 be brought to the fore, the input is low, all of the preferably in the first t.t.l. 10kHz E-* H 33p 470 reference current is supplied t tl B C 213 470n sentence. Minimum payment from the 5V rail, but when the pwm. of £30 is made for published 8`1/ 0 to 10V input I LF356N circuits, normally early in the input is high, current has to be out out drawn through the diode from 1N4148 month following publication. the inverting output stage. The diode and switching transistor 0V must turn off quickly, but their T21 on resistances do not greatly 4.77mA 5 11 affect performance. Current -to - 12 2N5459 voltage conversion and two low- 13 723 pass filter stages are provided 3 by the output circuit. I have followed this arrangement by a T1pop 10kHz notch filter (parallel T) 7>1k5 to remove modulation frequency break through. -15V When the 723 is driven from

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 71

www.americanradiohistory.com and four are pressed together to Sequence for a correct code entry: - release m and Power on latch IC,,Ä RST2 Pressing `'' ` 'sé "ën, IC3b, Q -( Alarm disabled (approx 11s) X digit of the code, triggers the Power on first monostable device, IC,a. RST1 - The output of IC3a will be .,. Clear ©8,3 pressed / released high, provided that it has not IC2a.CLIC2b.CL been triggered. As the output

Contact bounce of IC2, goes low the rising edge of IC2,'s B input (switch bounce IC2a, A E pressed / released is accounted for), through I z3 Os 1C2,,-(71. IC2b. f pressing and releasing key five Contact bounce as the second digit of the code, IC2b.B M5 pressed /released triggers the second monostable, IC26. Q 1C2ó, a,IC1n,D Output of this device Contact bounce feeds the D input of latch ICI° IC1a, CK 2 & © pressed/released and pressing and releasing keys Latches with first I two and six together (third and 1E10 Q Code o.k.- fourth digits of the code) latches ICI, Q output high. Output of IC1a,O JI; Alarm disabled IC,a, being low, inhibits firing, of the s.c.r., even after ils, during which the alarm is and the critical phase is over. Electronic ignition key disabled. If any of the system- The spare second half of IC reset keys is pressed (1, 3 or 8) serves as an output latch, the Q Your car can be made burglar alarm, thwarting even the during this period, another lis output of which energises a proof if it can only be started by shrewdest car thief. * cycle is initiated by IC.3,. This t.t.l. relay on whose normally - entering a code on a keyboard. When the ignition is first inhibits further code entry and open contacts switch a further With this circuit, the code has switched on, latches IC,a b and the alarm is activated at the end higher power 9V relay with to be entered within a time limit monostable circuits IC2a.b are of the cycle. When the correct normally open and normally and the code cannot be cleared by RST, and reset signal code is entered during the initial closed contacts. The normal! corrected without setting off the RST2 initiates an l is period, l is period, reset keys three closed contact releases the

+5V F é 9 47k 47k

200p 100y 1k SV 7805 1A 0

R/C C R/C C Z A A To key r 74123 74123 7474 IC2a a 5 7400 (16) (16) (14) (14) (7) (7) 18) (8) B -B 7474 7400 74123 74123 CL CL 74123 1 1 74123 +5V 1 470 or 11( 1k 1/

Code Horn relay o. k. +12V (existing) Pv CL (71

IC1b 1k IC1a D 7474 7474 CK II P Q 1N4002 _ Horns . +5v CL 1 3k9 33k 1:11: V L000p +5V Horn 1k SCR switch 33k 400V R/C C lk 1A qri +12V -t Ignitron key 1k 1000p 0 IC3a 1 1 1'2 7400 To 7805 A CL V274123 R/C C +5V B Q +5V 1C3b 7123 Z 470 r - - A a ^ il Enter code To 1N P. 4 contact 4001 n.o.. n.o. n.c ,1000p +SV ZN 3019 3k9 +5V 4 470 L TTL relay RST 470 9V 1k relay 2N3019 1000p T

Note Decouple oil ICs with 10n

7; 'BONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com s sort across the ignition contact e Weaker and the normally-open Common ruthode Easy to read contact offers a holding path for the 9V relay, even during reset. hexadecimal If the correct code is not LT5C7R .2 display entered during the lls period, the car horn is switched on. One seven -segment display Turning off the ignition key 1k made to display hekadecinial sloes not stop the alarm but Ik 7.1k values is awkward read. pressing b the horn button will Devices for displaykig binary- momentarily inhibit conduction tncoded decimal vagues don't cf the s.c.r. 401 7x1N4148 respond to binary inputs above Use of the secondary 9V relay 1001 but this circui- display a ensures reliability, even if the hexadecimal value in decimal l attery is not fully charged and form and its most-sgnificant voltage curing the dip caused by decoder is capable of reading darting the engine_ Supply between zem and five. is cecoupling not critical as the b c d e f g a b c c e Hr De Smet Willy Onlug àrcuit only needs to operate ICS Bl 8t IC4 --VSS Zomergenl properly while the car is 04511 LE -Vss CD4511 Belgium stationary. Malfunctions -VDD LT -VDD occurring while the engine is c b o d r b running are of no consequence since the 9V relay only acts when the ignition key is .070 twitched off. G. Varkey Cochin Naval Base Kerala (-1 hidia 0 0 0 0 =Or a driver under the influence of ins b. l.s.b. 1.1cohol - Ed.

Differential line driver

Pause replaces transformer switch Solenoid & Auto-stop auto-stop There are many applications true transformer action. (S912) (S913) where balanced line driving is Devices chosen have low noise Mctor supply required, particularly in audio figures and can drive 600Q lines .20V on applications where noise is a directly. The circus has a 22dB OV off problem. Transformers are overload margin when driving

Replay OV expensive and suffer from OdBm into 600Q, and greater Record .13V limited bandwidth and stray than 64)kHz full power <,`> 1k magnetic fields so this circuit bandwidth can be achieved by uses opamps. careful choice of resistos. BC182 . // Output maintains constant S. Whitt Red Green- amplitude even if one balanced Ipswich line is earthed, thus simulating Suffolk

R1 OV

Input .-

One led shows six modes

In my application, this - red, record mode 60011. multivibrator driving a `three - - yellow, running (record) R2 balanced colour' led is used to indicate auto-stop effective output one of six modes of a cassette - red/yellow, pause (record) recorder but it can be applied to - red/green, pause (play) if any situation where d.c. winding auto-stop ineffective e switching is used. Connections shown are for the Supply tc the multivibrator is Hart Electronics VFL910 R = 10k split so that oscillation at about cassette deck. In other R1 = 10k 1 Total gain 1Hz only occurs when the pause applications. green and yellow R .30k unity switch is on. The six modes could be made to flash 1 R1 . R2 = 20k gain =2) indicated are alternately. Power supply: ±18V for mcximum C = 22p overload margin - led off, deck disengaged J.E. Wilson 1C1* NE5534 - running (play or wind) Leicester green, IC2= NE5533 dual op. amp. auto-stop effective ELECTRONICS & WIRELESS WJRLD DECEMBER 1984 73

www.americanradiohistory.com XY PLOTTER

by P.N.C. Hill More on the XY plotter Further constructional information and some software

Since the publication of the previ- described in this journal. An 200 step sequencer circuit. A ous article on the construction of interactive control program has much simpler circuit can be used an X/Y plotter in the January edi- been developed to allow diagrams to generate the sequence: tion of WW, I have received a to be drawn from a stock of pre- AB, BC, CD, DA, AB... Although number of enquiries requesting defined shapes and then anno- this halves the number of steps further information. Although the tated with a wide selection of type per revolution, useful results can A *The interactive control program can be first article was intended only to sizes and founts*. graph/histo- still be obtained: the circuit is obtained from this office. Please enclose a introduce readers to the idea of gram package also links a digital shown in Fig. 2. Only two D -type large, stamped and addressed envelope and constructing such a precision filter design program to the plot- flip-flops and two ex -Or gates are mark your letter 'XY Plotter'. instrument, I hope that this will ter so that frequency response required for each motor - the Fig.1. Simplified 400 step further encourage any would-be and impulse plots can be drawn motor direction is controlled by sequencer for controlling constructors. and labelled. the state of the external input to stepper motors. The software required to drive the ex -Or gates. This simply the plotter has also been inverts the feedback around the Driver circuits Fig.2. 200 step sequencer for expanded and re -written in Pas- counter formed from the two flip- controlling stepper motors cal on a CP/M-based system flops. The step pulse to incre- with reduced resolution. similar to the SC84 computer The driver circuit described orig- ment the motor position is inally might seem excessively applied simultaneously to both complicated to those who wish clock inputs on the 74LS74 flip- only to experiment with stepper flop. Step ID puke 2 14 motors. As mentioned previously Either of the above methods CK 74LS169 the aim was to achieve 400 step- can be used to generate the logic 3 per-revolution accuracy from the sequence used to drive the cur- B motors. To achieve this from the rent in the motor windings. The DIRECTION 12 U/0 C four -pole motors, the sequence power driving section simply 1 of excitation must be as follows: hooks onto the output of the sequencer. The exact design of A, AB, B, BC, C, CD, D, DA, A.. . the driver naturally depends on The rom sequencer described the type of stepper motors used previously performs this opera- and also on the loading conditions tion for both motors therefore of the motors. keeping chip count and intercon- Driver stages. Various factors

A nections to a minimum. How- must be considered when design- ever, those constructors unable ing the driver stages. A typical Output to motor driver stages to gain access to a prom program- scheme which might be used is as mer may prefer a more traditional follows. The selected winding(s) approach in generating the neces- is driven hard on as the sequencer 2 STEP sary control signals for either 200 output changes to the next state. D PULSE CK O or 400 steps. The rotor accelerates towards its +5V V2 400 step sequencer. The circuit next position, drive current being 74LS74 in Fig. 1 may be used to drive a then reduced to maintain the new single stepper motor. The rotor position and prevent over- d 74LS193 counter maintains the shoot. If the motor is driving a current position in the 8 stage predominantly inertial load, then Outputs sequence: only the top 3 bits are this maintenance current may be DIRECTION to used for this, the fourth bit being only slightly (if at all) lower than driver stages left disconnected. The counter's the main pulse current. However, up/down input serves as a motor if the load is frictional, then the direction control, so that pulsing holding current need be only very the counter steps the motor for- CK small; indeed, it may not be +sv 1/2 wards or backwards. The binary required at all, so reducing the 74LS74 outputs from the counter are power dissipation considerably. 13 8 decoded by the Nand gates. The In the case of the plotter the four final outputs marked motors drive a load which is part

112 A,B,C,D are connected to the frictional and part inertial: a com- power driver circuits, which in promise is thus sought. A maxi- Output sequence AB, BC, CD, DA turn provide current to the step- mum of 200mA per phase for the per motor windings. pulse current with a holding cur- 74 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com 38k c1 -mm-Fuse +30v 15 N 4 1A raw Set hold supply 2 13 1 B current 3k3

2 Direction control A '/2 74LS07 2N3053 from computer 7415157 74L574 5 Step pulse from A A Z80131 computer 8 +5V SEI. SIB. +5V 220 D1 1 J1S 1 Blue /white 1N4001 [lock Fwd generator BD131 Red s 3CK D2 Manual d 8 V Q override .5+ 330 I L5132 - - 74LS74 R 680 4 6 A 11 Orange Motor Rev J^ 330 windings 1032 4k7 Sequence (ORI controller 21L/ D3 10 74L5 88 B 1 411

12 Yellow 7415123 11 CK Q 9-- D4 M1 `` 330 +5V -e- ',2 741574 00000 '.. 8 Green Q D 330 112 58k 100p D5 V 1N5400 rent of approx 40 mA is found result during the current switch- suitable for the 12/24V motors ing process, most of which the obtained from Stewarts of Read- diodes (D, -D4 in Fig. 3) dissip- ing. These figures are not critical ate harmlessly. Failure to include and optimum choice will depend the diodes will almost certainly on the mechanical construction of lead to blown output transistors. the plotter. The on/off sequence is gener- Motor controller circuit. The ated by a circuit similar to that in common -collector driver circuit Fig. 2. In addition, logic for pro- originally proposed is ideal for viding manual control from two providing the two levels of current push -buttons is included to allow in a controlled manner. The fact movement of the pen independ- that the initial circuit was ently of the computer. This is par- designed for use with several ticularly useful when removing types of motor and transducer and re-loading paper. The move- contributes to its relative com- ment rate is also increased after plexity. An alternative (effective) about one second of manual con- method of driving the motor is trol to speed up the movement of shown in Fig. 3. If the discrete the pen over longer distances transistors are too bulky then whilst still allowing accurate posi- transistor arrays can be used, tioning at a lower speed. provided the maximum current The circuit is self-contained ratings are observed. Little or no (with the exception of the power heat sinking is required for the supply) and so needs to be built driver transistors if they are used once for each motor: Fig. 4 shows as the current remains at the Fig.3. 200 step, stepper only in the fully on or off states. a photograph of the completed higher level only when the motor motor controller and driver. However, the main regulating circuit. The component values is stepped. transistor will require a heat sink shown are suitable for the SLO- The circuit operation is basi- Fig.4. Photograph of completed if an appreciable hold current is SYN motors mentioned in the cally straightforward with the stepper motor control module. used. previous article. Resistor R5 sets possible exception of the modula- The manual control push It is also important to note that the maintenance or hold current, tion of the clock frequency by the buttons can be seen on the the actual measured current in R, sets current-pulse length, output of the 74LS123 monost- front of the board next to the the windings will not be exactly as supply voltage sets pulse current. able via R4. When either button is led indicators. The leds turn first predicted due to the very Best results may be obtained with pressed the mono -stable (M,) is off when the corresponding coil high self inductance and imped- a supply voltage typically higher triggered, so slowing the clock. is being driven to avoid drawing ance of the wire used in the than the motor's rated voltage. After a short -period (0.3XRZXC2 excessive current from the motors. Large back e.m.fs will Heating effects are not a problem seconds) the output returns high, logic. ELECTRONICS & WIRELESS WORLD DECEMBER 1984 75

www.americanradiohistory.com XY PLOTTER

the computer - necessary dur- Baud rate ing software development! Crystal oscillator generator +5V =13 Interfacing to the computer 2 CK 17 10 10 ->. 74LS163 74LS163 Any home computer is capable of 9 9 LD CO CK driving the plotter. Sadly, the 330 330 A D QA 08 OC QD interfacing facilities of most of the --A +5; 13T 15? j6 14 r 111 numerous hobby machines are far I-. from being standard. If parallel o< ,9600 4800 2400, outputs are available, then inter- BMHz Baud rates facing the plotter is a simple mat- ter. Two wires are required for Connect as required each motor: direction control and 1 step pulse. One additional wire is +5V required for each pen for the lift control, giving a total of six wires

17 for a two -pen plotter, plus the RRC 18 common earth line (of which f>-- M Cc 330 several are recommended for ,00p 1 =100n safety's sake). One standard 23 TNRL R eight -bit output port is thus suffi- 34 CRL cient. Additional input lines can Step pulse 1 40 12 TRC be added for feedback for finding 11 36 Direction 1 the paper origin etc. SBS 35 AY -3 -1075 0 This form of parallel interface PI requires a multi -core cable and Connect 39 9 Pen 1 as required' EPE cumbersome connectors, and 38 (See below) WLS1 Step pulse 2 offers no protection to the mic- 37 WLS2 external nasties .5v roprocessor from Direction 2 such as 25V lines etc. An alterna- 4k7 6 tive approach is to use a serial interface driven from the RS232/ 20 Ri D Pen 2 IEEE 425/426 output of the com- RS232 in END 5Fß PE FE DF puter. This is portable and flexi- 108 330 BC li16 13 15 ble and only requires two wires! WLS2 WLS1 Many uart chips are available

Framing 0 0 -5 which perform the basic shifting 0 1 -6 and timing operations necessary SBS=1 2 stop bits PI =1 Na parity Parity Overrun Bits per SBS=0 1 stop bits PI=O Parity 1 0 -7 word for an asynchronous receiver. 1 1 -8 EPE=1 Even parity Errors The AY 3-1015-D is one such EPE =0 Odd parity device particularly useful in this application as it can operate with- out a host microprocessor. It Fig.5. Serial interface for so increasing the clock frequency required for coil excitation, the requires a stable clock at a fre- graphics plotter. by an amount dependent on R4. direction being controlled by the quency of 16 times the baud rate. The clock base frequency is state of thé DR line. This is generated from a crystal - Fig.6. Photographs showing governed by R3 and C3 which, The 74L5157 is used to route controlled oscillator and divider the completed plotter in more together with the Schmitt Nand the control signals from either the circuit. Baud rates of above 4800 detail. Both stepper motors gate, form a gated oscillator. computer or the logic associated are advisable to allow a reason- can be seen attached to the The 74LS74 flip-flop and the with the manual over-ride but- able plotting speed to be pen carriage and the paper ex-Or gates provide the tons to the sequence controller. achieved. Figure 5 shows a suit- carriage. AB, BC, CD, DA sequence Pressing either button over -rides able interface circuit.

76 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com The incoming serial data is therefore be greater than this At any point on a line there are only two conditioned and buffered and fed number times the thickness of the L,/directions in which the pen can be stepped. Ideal line into the RRD input -of the device, wire. In the case of the 40Ib wire + + the parallel output appearing on the outside diameter is approxi- pins 26-33. The DR signal on pin mately 0.8mm. A pulley of, say, Line as drawn + 19 indicates a received byte of 7.0mm diameter requires 14 by plotter data and is reset by pulsing low revolutions to move the 21.2cm of the DRR input on pin 18. a sheet of A4 paper, which means The direction chosen -ewe + + results in the pen being circuit not that a pulley width of 11.2mm is r Although the has -0.05mm closest to the ideal line. been used with the plotter it has required. If the width is smaller Distance A is smaller been successfully used with other than this then the plotter func- than B tions satisfactorily except for projects. The gates connected to The diagram shows a line in the first quadrant. Lines in any the outputs of the AY 3-1015-D some long-term slippage. other direction use exactly the some algorithm except the two simply route the received data The completed plotter is shown possible step directions are different. strobe signal to either (or both) of in the photographs in Fig. 6. Both e.g. X, -Y for 4th quadrant rather than X, Y for the 1st. the sequencer circuits used. If the stepper motors are clearly visi- corresponding output bit is set to ble, as are the taut wires along (X-Dest, one then the sequencer is stepped which they run. Y-Dest) once. If the bit is left low then the Deviation from sequencer remains in its previous ideal line state. eg: Sending 01H steps the Controlling software Y (XT, YT) X motor once in one direction whilst 03H steps it in the opposite the plotter has been con- direction. Once structed and the electronics built (0 0) X and then interfaced to the compu- Improvements to the mechanics ter, the software development can begin. This may, at first mal number is obtained. For each Fig.7. Drawing straight lines. glance, appear to be a simple step the pen is moved in the X Some simple changes have been task, but there are a number of direction it must be moved by this Fig.8. Calculation of made to the mechanics which problems which can result if a few amount in the Y direction. Obvi- perpendicular distance of have improved the performance precautions are not taken. ously the pen can only move in point from the required line. of the plotter. It was initially sug- The first rule is not to use float- whole steps, so at each point one gested that button-hole thread ing-point arithmetic for the main must calculate the exact position The calculation of the deviation was suitable for the traction wires line and curve drawing routines, using floating point arithmetic from the ideal line is extremely along which the motors run. This since the inevitable truncation and then move the pen to the simple, as Mr Griffiths pointed does work extremely well; how- errors lead to inaccuracies which nearest actual location. When the out in his letter published in the ever, plastic coated stranded wire accumulate, as all pen position- end of the line is reached any February edition of E&WW, and produces better results as it can ing is naturally done relative to small error present must be cor- which is illustrated in Fig. 8. be tensioned to a greater extent. the previous pen position. If a rected or else it will propagate. Thinking in terms of programm- A source of suitable wire is a fish- positioning error occurs at any The problems mentioned are only ing we may call coordinates of the ing tackle shop as it is sold for use point the error remains from then the beginning, since we also have endpoint of the line (X DEST, Y in attaching to large hooks to pre- on. These slight error may not be to cater for vertical line without a DEST) and the current pen posi- vent even larger fish from biting noticable on small diagrams but division by zero error in the calcu- tion (XT, YT), both relative to the through the line. Various thick- on larger, more complex drawings lation of the gradient. Doubtless starting point of the line. The nesses are available but 401b the end may not join up with the it would be possible to devise rou- coordinates at which the pen seems the most suitable. start. tines to perform all these checks, would be positioned after the next A second improvement is to the For simplicity in the descrip- but if they were written in any- step has been issued are calcu- pulleys that run along the wire. tion of the software, the pen is thing such as Basic it would prob- lated for each of the two possible One pulley is fitted to each of the assumed to move in both the X ably take serveral minutes to next moves. These would be two motors which are in turn fit- and Y direction over the paper. In draw each line. Luckily, an altern- (XT+1, YT) and (XT,YT+1), the ted to the pen carriage and to the practice this is not the case as the ative exists. '1' referring to the one step moved plotter bed (or paper carriage). paper actually moves in the Y A glance at Fig. 7 highlights the in either of the two directions. We These should ideally be made of direction. problem. The central line shows then compare deviations from the Brass rather than aluminium Straight lines. This is the most the ideal (unobtainable) solution: ideal line obtained by both solu- alloy, since the latter seems to elementary routine (apart from The staircase route for the pen is tions, adopting the solution with promote excessive wear on the pen up and pen down). We may the best approximation. At every the smallest deviation. The wire. The pulley diameter should specify the endpoint of the line on point there are two possible direc- implementation of this is further be as small as possible to give the a cartesian coordinate system, tions in which the pen can next be simplified as the value of '1' (the best resolution and smoothest the origin of which is previously moved: one step in the X direc- line length) is constant and so performance of the plotter. defined at a suitable point on the tion or one step in the Y direction need not be included in the com- Finally and most importantly, paper. The X and Y coordinates of (the movement is either positive parison. The test may be imple- the width of the flat area of the the endpoint are passed to the or negative on each axis but this is mented as follows: on which wire runs (see routine which then moves the pen constant for any given line and so pulley the IF ABS[XT*Y_DEST position (wher- need not be determined at each Fig.13 of original article) must be from its current -(YT+1)*X_DEST] ever that is) directly to the end- step). We simply wish to deter- sufficiently great just to prevent < ABS[(XT+1)*Y_DEST] If the pen is up then no line mine which of the two options the wire from winding to the point. -YT*X_DEST] ends. This is best done by calcu- is actually drawn. If the pen is leads to the pen being positoned THEN MOVE IN Y DIRECTION lating of pulley revo- down then a straight line is drawn closest to the ideal line. If we cal- the number ELSE MOVE IN X DIRECTION lutions that must be made for the on the paper. culate the distance that each of appropriate carriage to move It is tempting to perform this the two solutions would place the ABS indicates absolute value. from one end of its travel to the function by calculating the gra- pen from the ideal line we can other. The pulley width must dient of the proposed line. A deci- then choose the best of two. To be continued. ELECTRONICS & WIRELESS WORLD DECEMBER 1984 77

www.americanradiohistory.com SERVO SYSTEMS by J. Rush* Digital derivative feedback at l.f. In a proportional -plus -derivative servo system in a model ship, a hybrid digital -analogue circuit gave better results in extracting the rate signal that the more usual lead/lag RC network.

It is well known that a resistance and the capacity. The impedance working with a model ship, and capacitor network such as that of the resistance can be taken as wish to consider frequencies in shown in Fig. 1 will produce the resistance; the impedance of the response region of yaw derivative action on any signal the capacitance X, is motion, say 0.5Hz. With careful injected into it. This effect can be shielding and f.e.t. amplifiers, X, used to produce a 'rate' signal in X, = 1/27tfC ohms could be made as high as 10MQ, servo mechanisms, but it has two so that to produce a lead angle of serious defects. The first of these for a frequency in hertz and capa- 85°, the capacitance need, is that the degree of phase shift citance in farads. The phase angle assuming no loss, is 0.36 N.F. depends very much on the fre- is then This is obviously undesirable and quency being differentiated. The a more reasonable value might be signal emerging from the tan' XN/X, for Xk and X, in ohms. 0.01 µF, which gives a lead angle *University College, London network, will be a combination of of only 17° and has an impedance a proportional signal and a deriva- The difficulty with the system of 32 MQ at this frequency. tive signal at +90° to it. The ratio is the size and quality of the capa- of these two determines the citance needed to produce a rea- Direct rate measurement phase advance, which unfortu- sonable phase shift at low fre- nately decreases with decreasing quencies. In Fig. 1 the capacit- frequency. The second drawback ance shown is assumed perfect, It was felt that this problem is the size of capacity needed at with no leakage resistance or self could be more easily overcome by = low frequencies, say 1Hz, to pro- inductance, and this can only be measuring the rate of change of Fig.1. Elemental CR circuit duce moderate derivative action. approached in practice with very the incoming gyroscope signal produces derivative action, The phase angle of the emerging careful layout and high quality, directly. This can be done with used to obtain rate signal depends upon the ratio of expensive and bulky capacitors. the gyro signal charging a capacit- information. the impedances of the resistance Suppose, as in this case, we are ance which is discharged at a fixed

5V

t= 0

7 L j CLR CLR 6 NZ k2 555 CK CK 3

K

5 5 1 I691k 10p 10n T,On LF 398 7 T TOn 3

L F 398 [ac zero!

[ dc zeroJ

t=0 LF398 Fig. 2. Circuit diagram of digital proportional -plus- derivative servo.

78 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

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rate by resistance, but this is prohibits the use of only two sam- really the same as the phase lead ple circuits. The electronics with network. The solution was to two circuits is also less straight- sample the incoming gyroscope forward, since each sampling cir- signal at fixed small intervals and cuit must hold for one clock cycle, take the output derivative signal sample for sufficient time to as the consecutive difference acquire the new signal level, and between two consecutive sam- then switch back to hold During ples. This gives a derivative sig- the sample period no rate output nal which easily works at low fre- is available and one also has to quencies and within noise limits, switch both sample circuit out- improves with decreasing fre- puts between the differential quency. amplifier inputs every other clock The incoming gyro signal can cycle. be sampled with a 'sample and A better solution is to use two thirds of the time, so that the Fig.3. System used to provide hold' circuit, which can be three sample and hold circuits, sample and hold needs to be velocity feedback. obtained as a single i.c., and one switched so that whilst two are driven by a clock signal which is would need a minimum of two producing the required output the assymmetric. Furthermore, the samples to produce a rate signal third is acquiring the new signal clock signals to the three sample for a given time interval. The rate level prior to switching to the hold circuits should be 120° out of signal is obtained by making the mode. For three holding circuits phase with each other. two samples the input to a high A B and C the required sequence The outcome of these require- gain differential amplifier. of differences for a continuous ments is the circuit diagram in In practice, sample and hold positive rate output is: Fig. 2. This was built from circuits suffer two distinct lags, medium and low specification hold settling time, and acquisi- B -A components with a clock rate of tion time. The first of these is the C -B 75Hz,and will produce a deriva- time required for the output to A-C tive signal from a 2V source from settle after a `hold' has been B -A 0.01Hz to 10Hz. The phase angle given. When measuring small dif- etc. at 0.01Hz is approximately 89.4°, ferences between consecutive and the largest capacitors are samples this hold error could With samples produced at the 1µF, these being low voltage introduce magnified errors in the correct time from a clock signal, types in the smoothing/lead cir- output, but for the sample and the above may be produced from a cuit. hold circuits used the hold settl- dual -channel, analogue demulti- The clock is a conventional ing time is of the order of 1 mic- plexer driven at the same clock 555 timer in a stable mode which rosecond, and for the frequencies frequency. This would feed the produces the 75Hz square wave. being considered the error can be two samples required from the This is then fed to the 74107, ignored. The acquisition time is hold circuits to the differential which is an assymmetric divide much longer, of the order of 20 amplifier, and thus produce the by three, producing two of the microseconds for the capacitor rate signal. From the sequence driving clocks needed directly. needed at the sample holding above it can further be seen that The third clocking signal is pro- times used in this instance, and each held sample is required for duced by 'anding' the comple-

+5V 100k

18k DG529 725 +

°-o 3k3 15k 18k I

>I .±Iro I I u 22k

- _ _ JI D _r_T. 741 51k 10k cs 18k Inpl.t o ^/V\, 33k 51k 22k

36k

1p 741 o Output 741 51k As 15k 10k

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 79

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Amplitude autopilot summing function. The of 90° minus half the switching former prevents direct feedback time of the clock. The Input higher -Sample point around the differential circuit, input frequency in 4(b) at about and the high frequency oscillation 1/5 of the clock frequency, shows Time that this would cause. considerable distortion and har- Difference monic content, and the phase signal Circuit performance lead, although on average being 90° minus half the switching time, The differential amplifier was Output r3 varies along the wave train. tested in isolation and produced From this it is apparent that excellent results. At this stage the the differentiality circuit will lag network of the final circuit was a) always produce some harmonic' not a used, and four -pole Butter- distortion. The constantly chang- worth low-pass filter with a ing phase at higher frequencies Amplitude breakpoint of 16Hz was to used made it impossible to prevent the attenuate high frequencies Sample point and oscillation with the simple RC lag provide a smooth output. described above, and the har- Input Although not strictly neces- monics produced would maintain sary, the differential circuit was d ll 1 oscillation in the absence of suffi- then used to provide velocity cient attenuation. feedback in the closed-loop rud- , 7 der circuit, as in Fig. 3. It was Having examined these wave- Difference forms it was then found that the signal then found that at even moderate derivative gains the rudder circuit problem could be solved by became unstable, and the rudder, increasing the clock frequency, Output 1 which was driven by a low -inertia thus decreasing the phase distor- A 411 A motor had a tendency to oscillate tion and harmonic content of the at about 16Hz. Various modifi- rudder servo signals to an extent cations were tried, including low- sufficient to prevent oscillation. The limit to which the clock fre- (b) IF ering the frequency first to 10Hz and then to 2Hz, and the use of quency can be increased depends Fig.4. Effect of differentiation ments of the two flip-flop outputs Bessel rather than Butterworth on the noise in the system. With network at higher input in a 7400 Nand gate. The three filters, but none of these proved increasing clock frequency, the frequencies. At (a), input is other gates on the quad 7400 pro- to be a solution to the problem. differential amplifier is amplifying one -twentieth of clock duce inversions of the clock sig- The reason for this is that smaller differences in the incom- frequency, giving little nals, used to help produce the although these active filters give a ing signals, and will reach a point distortion. Higher input a.c. zeroing of the sample and rapid attenuation of higher fre- where the noise in the circuit frequency at (b) increases hold circuits. The latter are quencies, they also produce large becomes comparable with the dif- distortion. LF398Ns, which have a compa- changes in phase in the region of ference in voltage between two ratively low specification in terms the filter breakpoint, so that consecutive samples. The most of a.c. noise, d.c. offset, hold along with the differentiator an important sources of noise in the setting time, droop rate, and overall phase lead of 180° could circuit are d.c. voltage offset in other important parameters of easily be produced, adding to the sample and hold circuits, a.c. sample cirçuits. The signal to be instability. At this point the active feedthrough of the switching sig- sampled is buffered by an invert- filters were discarded and the nal in the sample and hold circuits ing 741, feeding a common signal phase -lag network used in the and in the multiplexing switch, line. The sampled outputs are fed final autopilot was introduced. and noise in the multiplexing to three pairs of gates of a DG529, This network very largely eli- switch differential amplifier. The which is a dual quad analogue minated the instability problem, upper limit on input frequency for multiplexer. This is a latching since it had no inductive action, a given clock frequency will be version, but this facility was not and produced only a phase lag. governed by the degree of fre- needed. The addressing of the The derivative gain could be quency and phase distortion that 529 which goes 00, 10, 01, 00 increased by a factor of about 8 can be accepted. The circuit is etc. is taken directly from the before the onset of instability, actually measuring input voltage clock signals driving the second compared to the active filter cir- slew rate so it must be remem- and third sample and hold cir- cuits. However, it was found bered that for a real circuit there cuits, and the output feeds the impossible to prevent oscillation will be a maximum permissable two inputs of a 725N differential of the rudder servo at high deriva- sinusoidal input voltage, at a amplifier with a gain of 5.5. The tive gains, despite adjustment of given frequency beyond which the output at this stage from a pure the phase lag network. The circuit limits and `chops' the out- sinusoidal input will be a stepped answer to this problem lies in the put. sine wave leading in phase by behaviour of the differentiating In practical terms, the results approximately 90°. To reduce network as the frequency going gained from a prototype were instability problems and provide a through the circuit approaches very good. This was built using smoothed output to the autopilot the clock frequency of the circuit low-cost components with relat- summing function, the signal itself. The differentiating effect is ively poor electrical characteris- then passes through a high fre- shown in Fig. 4(a) and 4(b) for tics compared with what can be quency lag network (with gain) low and high frequencies. In 4(a) obtained. The prototype was built which produces a 90° phase lag at the input frequency is 1/20 of the without a specific printed circuit 16Hz, thus cancelling the deriva- clock frequency, and it can be board and made as compact as tive feedback above this fre- seen that the resulting signal is a possible, and in fact is contained quency. The only other item is the sine wave with very little distor- on a single board 10cm by 10cm. unity gain buffer amplifier and the tion which leads by a phase angle It will, however, deliver a usable 80 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com SERVO SYSTEMS

rate output for input frequencies hold circuits suffer from voltage from 0.01 Hz to 10Hz, i.e. over a droop. The sampled voltage in the frequency range of 1000:1; which sample and hold circuit is held as is far better than would be charge in the holding capacity, achieved with an RC phase lead and the voltage on it monitored by network. For nonsinusoidal input a buffer amplifier to produce the signals there are further advan- 'hold' output. The buffer ampli- tages because the circuit does not fier has a high, but still finite, contain any fixed time constants input impedance, so that the that are comparable to the fre- charge in the holdiing capacity quency that is being differen- will gradually drain away, result- tiated. This is particularly so for a ing in a decay or 'droop' of the buf- square wave input for which the fer output. The decay rate obvi- convention RC circuit gives very ously depends upon the buffer poor performance. input impedance and the capacit- If the square wave shown in ance size, so that the latter, which Fig. 5(a) is put through an RC is external to the i.c., is chosen lead network the output will have according to the sample fre- the form shown in 5(b), in which quency and hold time expected. the initial spike decays exponen- The present prototype uses sion, and there is thus no lower Fig .5. Ouput of circuit (c) tially. The rate of decay depends 0.01 IpF polycarbonate capacities limit to the frequency that maybe compared with simple CR on the time constant of the circuit rated at 250 volt and has a hold differentiated. network. and can be increased by making time of 26 milliseconds, so there In the this low -frequency the product of R and C in the lead is scope with this analogue sys- range the system may be com- network smaller. Unfortunately tem for extending the frequency pared to differentiation using the impedance of the capacitance range downwards by increasing microprocessors. The results increases as capacitance dec- the size of the holding capacit- should be very similar in terms of reases, so that this also leads to ances. quality of the output signal, and in greater attenuation of the output However, a point would be fact the digital form of this circuit and a higher proportion of noise in reached where this became described above is actually a mic- the amplified output. Decreasing impractical, and the solution then roprocessor with a single pro- the value of R has the same effect. is to change over to a latching gramme 'hardwired' into it. A Figure 5(c) shows the output that digital holding circuit. The conventional microprocessor, is obtained taken before the high incoming signal is still sampled Z80 for example, would be more frequency attenuator in this case, with a sample and hold circuit, easily adapted to changing consist of short alternating pulses but the output of this is then fed to requirements, but would be con- of 13 milliseconds duration with an a -to -d convertor. The hold siderably more expensive. For no tail off. Because there is no time is thus reduced to the con- the frequency range in which the synchronization it will sometimes version time of the a -to -d which prototype operates, similar con- occur that the circuit samples the can be very short. Each output siderations apply, with the added input during a transition, in which line of the converter then feeds a provison that the analogue solu- case the pulse will be slightly binary latch, thus holding the tion will inevitably give a more longer. digital signal indefinitely. The accurate signal with less noise, A further benefit of this princi- latch is sampled by d -to -a conver- then a microprocessor equiva- ple of operation is that there is no tors to reproduce the original ana- lent. The added complexity of the lower frequency limit, although a logue voltage, and the remainder microprocessor and the act that change in technique would be of the circuit would be the input and output circuits called for for frequencies in and unchanged. System clocking fre- operate with discrete voltage below the cycles per hour range. quencies may also be extended levels can only degrade the qual- This is because the sample and downwards by frequency divi- ity of the final output signal.

Continued from page 57 STEATITE MICROELECTRONICS, THORP ELECTRONIC VEROSPEED, SEMICONDUCTOR SUPPLIES Hagley House, COMPONENTS, Standsed Road, INTERNATIONAL, Hagley Road, Victoria House, Eastleigh, Hants S05 4ZY. Dawson House, Birmingham B16 8QW. 63 Foregate Street, Telephone: 0703 641111 128 Carshalton Road, Sutton, Telephone: 021 454 2655. Worcester. c.w.o. Mail-order catalogue. Surrey SM1 4RS. c.w.o. Exclusive distribution: Telephone: 0905 24277 Telephone: 01 643 1126 Sanken. Speciality: Memory I.ts. c.w.o. Trade counter. VSI ELECTRONICS SWIFT SASCO, TODAY ELECTRONICS, (UK), Roydonbruy SOLID STATE SCIENTIFIC, PO Box 2000 11 High Street, Industrial Park, Horsecroft 275 King Street, Gatwick Road, Swanley, Kent BR8 8AE. Road, Harlow, London W6 9NF. Crawley, Sussex RH10 2RU. Telephone: 0322 60838 Essex CM19 5BY. Telephone: 0279 35477 Telephone: 01 748 3143 Telephone: 0293 28700 c.w.o.Speciality: Power c.w.o c.w.o. or credit card. Retail c.w.o. or Access (£5 minimum semiconductors. counter. order). Speciality: Mullard surface - mounted components. STC ELECTRONIC SERVICES, TRIDENT MICROSYSTEMS, WATFORD ELECTRONICS LTD, Edinburgh Way, THAME COMPONENTS, 53 Ormside Way, 33 Cardiff Road, Harlow, Essex CM20 2DF. Thame Park Road, Redhill, Surrey RH1 2LS. Watford, Herts. Telephone: 0279 26777 Thame, Oxon OX9 3XD. Telephone: 0737 69217 Telephone: 0923 40588 c.w.o. Telephone: 084 421 4561 c.w.o. Retail Shop. 81 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com NEW PRODUCTS

MICRO TRACKER BALL Developed from their tracker balls used in military and air- traffic control applications, Marconi have produced a tracker ball control for use with microcomputers. There are advantages of such a device compared with joysticks or move and change direction very 'mice'; they offer more accurate rapidly. CARETAKER FOR positioning of the cursor than The first issue of the tracker THE BBC joysticks and do not require the ball has been aimed at users of The Caretaker rom for the BBC can be switched off) may not table -top space needed for the BBC micro and is supplied Micro is a collection of utilities save much typing time, but mice. with utilities software. This for Basic programmers. Among should certainly prove an The two-inch diameter ball is allows it to replace the cursor these are a search -and -replace attraction to refugees from the in non -slip contact with two keys or be used instead of a facility for editing programs, ZX Spectrum. shafts accurately positioned at joystick. The software allows commands for merging Several routines in Caretaker 90° to each other. Each shaft is the user to define the function programs and for loading or parallel those of Beebugsoft's fitted with a slotted disc; light of the three keys built into the saving individual sections, a excellent Toolkit rom: some of source and photodetectors tracker ball housing. Further 'bad program' recovery routine them are less easy to use, measure the rotation of the disc software in preparation include and a very comprehensive though they allow rather more and electronic circuitry c.a.d. and graphics programs. compactor for saving memory flexibility. A useful 'help' page translates these into X and Y Computers with an RS232 input space. is available to remind the user coordinates. The resin ball can also use the RB2 by the One novel feature offered by of the commands and their rotates freely in any direction addition of an interface card the package is single -key is not syntax. and its ease of use makes it fitted inside the control's a strictly accurate description of Caretaker comes in an 8K suitable for long sessions. With housing at extra cost. Prices the process since you have to eprom and costs £ 133.35 the appropriate software the vary according to the distributor press the tab key at the same Computer Concepts, Gaddesden RB2, as it is called, is capable but are about £50. MEDL time. A set of stickers is Place, Hemel Hempstead, of moving a cursor one pixel at Power Division, Carholme supplied to indicate which key Hertfordshire HP2 6EX, tel. a time on a computer graphics Road, Lincoln LN1 1SG. does what. This facility (which 0442-63933. EWW 205 screen while also being able to EWW 206

FALSE COLOUR SATELLITE WEATHER MAPS A complete system for receiving outlines of the countries, which World. With the addition of a mounted close to the antenna Meteosat pictures, which may be concealed by clouds, suitable antenna, the NOAA and ensuring the optimum signal includes everything from the and coordinate points at 10 - Meteor satellite signals at strength and picture quality; an antenna to a colour monitor, is degree spacings. Although 137MHz may be received. s.h.f. down -converter to produced by Microwave Meteosat is stationed above the However the images may only 137.5MHz; the main six - Modules. The processed image equator and can monitor about be captured during their brief channel receiver which as displayed by the MMS 1690 one third of the Earth's surface, fly-past periods unlike incorporates the power supply; system is received in segments; as a European satellite it gives Meteosat, which provides and a digital scan converter 24 in the case of visible pictures performance to the images continuous data. which translates the signals into and 9 for infra -red. Each image covering Europe which are The system consists of an pictures and can also convert is provided with a caption which updated at least twice an hour. easy -to -assemble antenna kit, the monochrome images into gives date, time (GMT), type of The receiver is equally suitable for mounting on a colour by assigning colour image and segment code. suitable for other vertical mast; a 1691MHz GaAs values to different bands of the Meteosat transmissions include geosynchronous weather fet preamplifier which is 64 grey levels obtained. satellites spaced around the weather-tight and may be Sequences of weather images can be retained inexpensively by recording the signal onto a good quality cassette recorder. A library of images can be built and replayed through the scan converter to simulate a time - lapsed sequence. The system is completed by a colour monitor. Component parts may be purchased separately. The complete system costs £1738, excluding tax, claimed to be 50% cheaper than any similar system. Microwave Modules Ltd, Brookfield Drive, Aintree, Liverpool L9 7AN. EWW 207 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com * * NI -CAD BARGAINS * * COMPUTER PERIPHERALS Re -chargeable Nickel -cadmium batteries in stock. Ex -equip- RALFE ELECTRONICS * *1 ment but very kttle used condition. DEAC 1000DK Button 10 CHAPEL STREET, LONDON, NW1 TEL: 01-723 8753 Stacks 6 cells - 7.2V. See 25 x r diem. Capacity IAH. E1 inc. 1.6MB 8" FLOPPY DISC DRIVES - VAT (p&p 3p) DEAC 6000(7 Button stacks 3 cells - 36V. New Stock See 15 o 1r diem. Capecnt 0.6AH £1.50 inc. Ip&p 20p1. Also evaiSNe - PCB's from which these After our recent sell-out of the DRE7100 FDDs. removed batteries have been containing to offer another bargain package Transformer, Diode rectifiers, smoothing ca- we are pleased pacitors, DPDT Relay, fuses etc., easily as follows: BRAND NEW American 'MFE Corp' adapted to charge either of the above model M-700 DOUBLE -SIDED 8 -Disc Drives. stacks. ONLY E1.50 each ìsc. VAT GAP 750. Massive storage capability up to 1.6MBytes. Full IBM comparability. External power requirements STEPPER MOTORS ** ** 'OSCILLOSCOPES' are ±5V at 1.2A and +24V at 11A. Full spares/ Brand new stock of 'ASTROSYN' Type 20PM- HEWLETT-PACKARD 141A Storage Osnlloscotre All these units are sold back-up available U K (Elcomatic's). Current list AU55 stepper motors. 28V DC. 24 steps per rev. HEWLETT-PACKARD 1707A dual trace 75MHz E750 in full operational s £315 15 oz -in torque (u 100PPS. length over Body 21/", TEKTRONIX 454A dual trace 150MHz sweep delay E950 condition and diameter 2'', shaft 1/4- diam x 41/4- spirally TEKTRONIX 453 do al trace 50 MHz sweep delay f600 calibrated to spec -- NOW LOWEST PRICE EVER £160 INCLUDING threaded. 16oz. Price - Weight each E11.50(p&p display below All prices are MANUAL INC CARRIAGE & INC VAT -- 50p). Connections TELEOUIPMENT Shi - see supplied. INC. VAT. TELEOUIPMENT 067 dual trace 25MHz sweep delay £350 subject to D'S dual trace 50 MHz sweep delay f450 additional STEPPER MOTORS TELEOUIPMENT * * * * TELEOUIPMENT 053 c/w dual trace & differential units f375 VAT & carriage 8in SHUGART type SA800 In stock used, but excellent condition, 4 -phase steppers. M - ISecuricorl - £10 steps/rev motor with (removable) gearbox giving a 300:1 TEST EQJIPMENT ** ** Floppy disk drives. We are pleased to say that we have reduction. 6V DC operated. Complete with a driver board SONY/TEKTRONIX 35 SCOPE } kst price. rad input. Motor these in stock now after our sell-out a few months ago. requiring lust a single 6V and pulse REGUVOLT StVA C\Ts Sine wave 230V, AC £100. condition single -sided drives to measures 1" x 2" MARCONI TF868 LCH Bridge Used but excellent VAT diameter, gearbox 3' MARCONI TF2600 Electronic Multi Meter 800KB. Few only at the same price £90 inc & 23" output shaft 3/16". MARCONI TF893A Audio Power Meters £85. carriage & Zeroxof user handbook. Also to those too now Sold complete with con- MARCONI TF2502 RF Power Meters. DC late for our last stock of 19Mbyte Winchester - we nections, CCT diagram of 1GHz 10w fsd £350. have some coming in ca. £125, please call. motor. CCT datais of half - MARCONI TF2701 Iv -Situ Universal Com- stepping etc. All for.just ponent Bridge E250. £& VAT WO.. POWER SUPPLIES inc. (p&p ROHDE & SCHWARZ 'SDR" AM Signal Generator 0.3.1 GHz. * SWITCHING * Time The following DC power supplies are available now TEKTRONIX 2901 -mark Generator fully OPTICAL ISOLATORS ROHDE & SCHWARZ Resonance Frequency Meter 470MHz2.5GHz. from stock in limited quantities All tested and SPERRY UNIVAC M4000 opto-isclalor units providing 2KV of ROHDE & SCHWARZ Polystop SWOB II guaranteed. _£20 insulation between Moderns and Terminals. 25 way 'D' connec- BRUEL & KJAER Heterodyne Voltmeter 0.5-240MHz. 5V in 10 Amps __£18 12V16A1110V.In) ... tors (RS232C Interface) in and out. Measures 9x5x7' Com- AIRMEC Display Oscilloscope 279 4trace, 14x10 CRT £195. 5V it 20 Amps... ._. £20 5V -.t 40 Amps £30 inc vat & Amps. £40 19V 'r' 30 Amps. .. £40 plete with handbook El 6.50 PP RIKADENKI 3 -channel Chart Recorder. Model 8341 5V 60 BECKMAN TURNS -15V, 12V& -5V n 11A, 4A and 40A £50 TELEOUIPMENT 561 SCOPES POWER CUTS??? ALL PRICES NOW INCLUDE VAT CARRIAGE + E2 EACH s COUNTER DIALS A bulk purchase of the se auahty Miniature type (22mm diam.) Counting oscrIloscopes enables us to o11e, stocksolianslstonsedElOaesce itiioMein ererre lot CENTRIFUGAL BLOWERS e use. These are outs ln potyptoo * ergency * end new with mounting them for sale lot lust _100 +vat topdualily UP to 15 turn "Hellpots'. Br wall black base. TORIN Type U62B1 230V )supplied,. Spec,l,calion as follors CadStart instructions Only £2.50 each. Inc VAT 8 has solid slate pp DC SMHb ` ensItIc,ry very powerful 1200W. 3.000rpml centrifugal fans Bandwidth ange over to charge NI -cad cells when mains supply SmV/div Sweep speeds trom for large rack or appli 'TELEVISION SERVICE KIT' on (bads not suppled). site 12.1.51n Buy now cooling enclosure extraction sooms/d,v to tes 8. Ocm CRT late,íe,022- neecrspp cations Overall dimensions 20xl 2 cros, outlet 6x4 Labgear T V Service pont We have managed to obtain a stock of Eeternal %& Z mod «purs fits nice acanable 2VDC,Mains 50H, Inverters ms. BRAND NFW. Surplus stock. £15 each inc. equipment affording vast savings on new price. Ali items are at & inc handbook 100W VAT, pp £1.50. ALSO SEE LEFT HAND COLUMN sold in full working condition and guaranteed Zero x. (Carriage Et0, LABGEAR COLOURMATCH CM6004PG. UHF TV Pattern * TEKTRONIX * MODEL a generators. Grey scale, variable level cross -hatch & * SWEEPERS * FILE MANAGER SYSTEM * ROTRON INSTRUMENT « TELONC 2003 System 800-1500Mhz £325 4907 Option 31 (Third disc drive) Jot patterns. f35. Inc * e-- COOLING FANS * MANIC SM2090 with 500-900MHz plug-in £175 4051 Graphic System compatible. T..1 CM601ORG Gated Supplied to fully tested excellent * LABGEAR COLOURMATCH KNIGHT KG -687 3-220Mhz £150 GPIB (IEEE 488-1975) compatible * Rainbow colour pattern generators. Cross-Hatch/dot & * condition, as follows: t* 115V. gated rainbow IRGBI colour bar patterns.. £65 inc. PLEASE NOTE. All the pre-owned equipment shown has been carefully # 4'/zx41/2x1mT £5. 230V same size tested in our workshop and reconditioned where necessary. It is sold in £5.50. 115V 3 x 3.1 YY' f4. 230V 3'' size, UNAOHM E0684 PAL Colour -bar & pattern gen. £275- e first-class opera-ional condition and most items carry a three months' brand new E6. Also small Quantity 115V KORTING 82512 PAL/NTSC Colour &pattern gen L275- guarantee. For o.ir mail order customers we have a money -back scheme. M 41'2 size, brand new E6. Postage each - l' 'Mail Ordercustomerspleaseadd a2.50postage ea item Repairs and sera icing to all equipment at very reasonable rates. PLEASE * 50p please wW 10 _ADD 15% VAT TO ALL PRICES. EQUIPMENT WANTED. PLEASE WRITE OF PHONE CIRCLE 57 FOR FURTHER DETAILS.

Build Your Own PC

IBM/XT compatible mother board (blank) £99.95 B 8 T with 128K Bytes of RAM £599.00 5-1/4 DSDD 40 trk drives only £109.95 XT compatible units from £1499.00 Full range of PC TO 90 compatible boards available. 05 9 Create your own PCB ARTWORK Build the TDS 900 into smARTWORK lets you create and revise PCB artwork on your IBM. Requires 192K your products, program it RAM, colour/graphics adapter, Epson printer and Microsoft Mouse (optional). ONLY £995.00 with a VDU and your forecasts become fact. 6801 Micro Control Systems Analogue and power control I/O in a single board computer. 6801 Micro Control Sys- tem designed for distributed control or standalone use: 6801 or 68701 MPU with 2K ROM, 128 RAM, timer, 8 12 -bit analogue I/Ps, 8 -bit analogue 0/P, 8 AC or DC inputs or outputs. Typical Systems from £250.00

FREE delivery within UK All prices fully inclusive Dealer enquiries welcome. CONGUIN SOFTWARE 14 GOODWOOD CLOSE, MORDEN, SURREY, SM4 5AW No callers please. Phone 0524 381423 * Single board computer. CIRCLE 75 FOR FUR'T'HER DE'T'AILS. 12k RAM and 8k ROM (expandable). All C-MOS for lower power. FORTH EDR editor for DEC language. Compiled and fast. On -board screen -editor, compiler * Keypad editor similar to KED an EDT and debug facilities. * Uses no host time or memory when editing tr Easy connection with serial * Fast Response and parallel channels, A/D, D/A * Edits PDP-11, LSI-11, and VAX files converters, triacs, printers, Why burden your overworked DEC computer with the task keyboards and displays. of editing files? use the new EDR front end processor to do your editing - for a mere £350. EDR intercepts the serial line between your terminal and DEC computer, and provides a powerful keypad editor with fast response. Triangle Digital Services Limited DEC users familiar with KED or EDT will be instantly at 100a Wood 5t.. Walthamstow. London E17 England Telephone 01-520 0442 Telex z62284 (Ref 775) home with with EDR. For more details of this unique device Stynetic Systems Inc. 11780 Flowerfield Building, 1 St James, New York contact: Telephone (516) 862-7670 Agents in USA, France, Switzerland, Netherlands, S Africa, Australia Andelos Systems Telephone: (0635) 201150 Solina, Bucklebury Alley, Cold Ash, Newbury, Berkshire RG16 9NN lr 30 FOR FURTHER DETAILS. CIRCLE CIRCLE 61 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD DECEMBER 1984 83

www.americanradiohistory.com REQUIREMENT: AMPLIFICATION SOLUTION: CRIMSON! More than ever, Engineers, Enthusiasts, & Professionals require a reliable source of quality amplification, crimson continue to meet this demand with a comprehensive range to suit virtually every application and support this with friendly advice and back-up. Our prices have remained stable for 18 months and with two regional distributors and our own mail order system, there has never been a better time to choose the best. MODULES

Power amplifiers bipolar type. Incorporating full electronic protection, Still the reference kit amplifier! for less than £250 you can own an esoteric integral heatsink bracket, high slew/low distortion circuitry i <0.01% THD TYPICAL) pre -power combination with the added pleasure of building it yourself. TYPE MAX O/P SUPPLY(DC) PRICE Write for our full brochure and review reprints. CK1010 Stereo pre -amplifier £92.00 CE608 60W/8R +/-35V £21.50 CK1040 Stereo P/A 40+40 WPC £121.00 CE1004 100W/4R +/-35V £25.00 CK10 0 Stereo P/A 80+80 WPC £134.00 CE1008 120W/8R +/-45V £28.00 CK1100 Stereo P/A 100+100 WPC £151.00 CE1704 200W/4R +/-45V £35.50 MC2K M/C kit for CK1010 £25.00 CE1708 180W/8R +/-60V £35.50 P.S.K. Pre -amp power supply £20.00 CE3004 320W/4R +/-60V £49.50 PRO POWER NEW LOW POWER A new range of 19' rack mounting power amplifiers are undergoing field CE308 30W/8R +/-25V £15.90 trials for launch later this year. Please contact us if you have a particular Power amplifiers Mostet type. Ideal for heavy duty use i.e. disco's or requirement for this type of amplifier as the final design will depend on your - needs! driving line transformers, dogrel heatsink bracket, ) <0.02% THD TYPICAL) FE908 90W/8R +/-45V £30.00 FE1704 170W/4R +/-45V £39.00 TO ORDER Pre -amplifiers stereo modules with R.I.A.A. eq. M.M. & line input, needs Send cash with order or quote Acces/Mastercharge card no. All prices vol and bal pots and input switching. Can be used with MC2 module to include VAT, P&P. allow use of low O/P MC cartridges. CPR1X STEREO +/-12V/20mA £33.90 DISTRIBUTORS MC2 STEREO +/-12V £23.00 London: Bradley Marshall Ltd., 325 Edgware Road. NEW SUPER CPR North: Wilmslow Audio, 35/39 Church Street Wilmslow. CPR2 STEREO +/-12V/20 (47.95 EXPORT Full details of our complete range including heatsins, toroidal No problem, but as postage varies so much please write fora proforma power supplies, active crossovers etc. available on S.A.E. invoice. CRIMSON ELEKTRIK STOKE PHOENIX WORKS, 500 KING STREET, LONGTON, STOKE ON TRENT, STAFFS. PHONE 0782 330 520

104 MARCONI 0 METER TF329G 50KHZ-50MHZ 0150 706 MARCONI UNIVERSAL BRIDGE TF1313 0.25% £200 BERG LOW PROFILE 14 PIN DUAL IN LINE I.C. SOCKET manufactured from glass filled LOOK! 108 MARCONI INSITU UNIVERSAL BRIDGE TF2701. Battery polyester to UL94V-0. £7 for 100, £31 for 500, £56 for 1000, £256 for 5000, £460 for Operated £300 10,000, £2100 for 50,000, £2,700 for 100,000. Sample 10 sentfor £1.20 + 30p p&p (£1.73 UNBEATABLE VALUE 109 Wayne Kerr Autobalance Component Bridge 8421 0250 inc VAT) TANDON 57," THINLINE FLOPPY DISK DRIVES 114 Wayne Kerr Component Bridge 8521 ICT375) L 100uH- BERG LOW PROFILE 16 PIN DUAL IN LINE I.C. SOCKET as above £8100, £36 for 500, SINGLE SIDED DOUBLE DENSITYS100 500kH; C1 pF-5F; R1 milliohm-1000Mohm £35 £65 for 1000, £295 for 5000, £530 for 10,000, £2390 for 50,000, £4300 for 100,000. Sam- DOUBLE SIDED DOUBLE DENSITY £130 117 Wayne Kerr VHF Admittance Bridge 8801 will Source S161 ple 10 sent for £1.40 + 30p p&p (£1.96 inc VAT). BRAND NEW S Detector R161 £400 WIRE CUTTER AND STRIPPER Tempered steel blades spr- DON'T DELAY 119 MARCONI AM/FM Mod Meter TF2300S 2-10OMHZ £375 ing loaded with moulded red P.V.C. handles. Cutting and - 123 AIRMEC MOD METER AM/FM type 2103-300MHZ.... f95 stripping adjustable up to 6.0mma. Overall length 135mm, ORDER TODAY! 124 MARCONI RF MILLIVOLTMETER TF2603 50KHZ-1500MHZ weight 64 grms, 10 for £15, 25 for £34, 50 for £63 100 for £116, 1mV-31/FSD 0315 500 for £525, 1000 for £1000. Sample pair sent for £1.75 + H.P. SPECTRUM ANALYSER 8551A 10MHZ 12.46HZ P.O.A. 125 MARCONI ELECTRONIC VOLTMETER TF260420HZ 1500MHZ AC/DC/Ohms AC300mV-300V POD. DC 200mV- 25p p&p (£2.5 inc VAT) with 851 B Display METAL FILM RESISTORS FZ4 manufactured by C.G.S. semi -precision with a standard TEK455Dual Trace 50MHZ Delay Sweep 0650 1KVFSD 1175 144 AVO MULTIMETER Modell P&P tolerance of +-2% and a temperature co -efficient of better than 100 ppm/oc. We have a GOULD OS 3500 Dual Trace 60MHZ Delay Sweep 0600 T7 020 146 AVO MULTIMETER Model 8 P&P C7 £45 full range in stock from 100R to 1 MO. All bandoliered. £2.50 per 1000 any one value. OSCILLOSCOPES WIRE WOUND RESISTORS. manufactured by E.R.G. Type 16 ES with a standard toler- 152 MULTIMETER U4324 33 switched ranges20K Ohm per volt ance +-5% of nominal resistance value. All values in stock. 2 TEK 454 Dual Trace 150 MHZ Delay Sweep £700 Crimple with leads S battery. Brand New. One year guarantee 6 TELEOUIPMENT Trace 3 watt series £3.50 per 100 any one value + £1 p&p (£5.17 inc VAT) 083 Dual 50MHZ Delay Sweep . í400 P&P £4 £I6 6 watt series £6.50 per 100 any one value + £ p&p (£8.63 inc VAT) 7 Tek 453 Dual Trace 50MHZ Delay Sweep £375 160 FARNELL STAB PSU TS1/30/5 0-300 50. Current limiting 10 watt series £10.50 per any one value + £1 p&p (£13.23 inc VAT) 9 COSSOR 4100 Dual Trace 75MHZ Delay Sweep £375 Metered T65 ALUMINIUM FOIL CAPACITORS manufactured by lskra 2.25 MFD 385V A.C. WKG axial 10 SOLARTRON CD1740 Dual Trace SOMHZ Dual TB ... £250 161 FARNELL STAB PSU 70830/20-300 2A Current limiting tupe. Body length 40mm x 23mm £25 per 100 pcs, £115 per 500 pcs. £212 per 100 pcs. 14 TEK 585A Dual Trace 85MHZ Dual TB Delay Sweep £200 metered 050 £980 per 5000 pcs, £1800 per 10,000 pcs, £4,165 per 25,000 pcs. Sample 10 sent for 15 COSSOR CDU 150 Dual Trace 35NHZ Delay TB £200 163 ROBAND VAHECO PSU type 33-2 0-33V 2A Current limiting £3.00 + £1 p&p (£4.60 inc VAT) 17 SELABS SM111 Dual Trace 20MHZ C200 metered lin current production) £100 BRITISH MADE TRANSFORMER. input 240V at 50HA, output 12V -0-12V 1/2 amp with 23 SOLARTRON CD1400 Dual Beam 75MHZ 0100 169 KINGSHILL STAB PSU Model 500 0-600 0.5A. Current limiting Metered P&P C7 G0 built in thermal overload circui I. P.C. mounting £25 for 10 + VAT £ 115 for 50 + VAT £210 STORAGE OSCILLOSCOPES 180 BRANDENBURGH PHOTOMULTIPLIER PSU 470 10-2100V for 100 + VAT £950 for 500 + VAT £ 1700 for 1000 + VAT. Sample sent for £3 + 75p p&p 35 TELEOUIPMENT 01164 Dual Trace 10MHZ.. £350 5mA Metered C200 £4.31 inc VAT). 36 TEK 564 Dual Trace 10MHZ Delay Sweep C275 190 VOLTEO PSU Model 82-635 -/- 5V; -12V; 21V High PAIR OF MATCHED SPEAKERS 4 ohm 3 watts in teak finish cabinets with black/chrome 37 TEK SPECTRUM ANALYSER 50HZ 36MHZ. 547 Mainframe - current un -used £15 facia 71 /2 x 12" x 5" depth -1 sample pack (2 spks) £ 10.00+ £2 p&p (£13.80 inc VAT) with 115 and 1170 Plug-in Units P.O.A. 191 AC/DC ELECTRONICS PSU MODULE 251 5V 2A ./-12V 0.40 10 packs £9.00 each + £2 p&p (£12.65 inc VAT) 40 TELEOUIPMENT CT71 CURVE TRACER C400 Un -used P&P £3 015 12" VIDEO DISPLAY UNIT (green) complete with frame and P.C.B. incorporating time 42 H.P. SHE SIG GEN 6208 7-11GHZ 0350 206 BAK LEVEL RECORDER 2305 £400 bases/EHT, etc but minus case and simple power supply unit. Originally designed to be 46 H.P. UHF SIG GEN 612A 450-1230MHZ 1200 20916K MEASURING AMPLIFIER 26062HZ-200KHZ 0600 basically compatible with BBC Micro and Commodore computers. Circuit diagram sup- 50 MARCONI AM/FM Sig Gen TF2008106*-510MH2... C1,250 plied. Price per sample unit £60.00 + £3 p&p (£72.45 inc VAT) Quantity prices on appli- 210 50K BAND PASS FILTER SET Octave 8 3rd Octave 52 MARCONI AM/FM Sig Gen TF10668/6 10-470 MHZ . C325 Weighing Networks ABCD C550 cation. 59 MARCONI AM/FM Sig Gen TF995A/21.5-22OMHZ C250 211 BAK DIGITAL EVENT RECORDER 7502 £1.500 OPEN FRAME AND SHADED POLE MOTORS by well known manufacturers, 240 volt a/c 62 MARCONI VHF Sig Gen TF10648/5M 68-108;118-185,450- 225 OAWE OCTAVE BAND SOUND LEVEL METER type6419c C150 - many uses - Price per sample £1.50 + 75p p&p (£2.59 inc VAT). Price per 10 motors 470MHZ £110 281 H.P. LOGICSTATIC ANALYSER 16020 Cd50 £1.25 + 75p p&p (£2.30 inc VAT) each. 63 MARCONI OUTPUT TEST SET TF 10651or use with TF1064 8 286 AVO VALUE CHARACTERISTIC METER VCM 163 0275 ULTRASONIC BURGLAR ALAM - portable - wooden finish with internal alarm - easily TF995 range Sig Gens 175 293 MARCONI AF POWER METER TF893A 015 installed - mains/battery option - provision for window contacts and pressure mat - 66 ADVANCE AM Sig Gen E2100KHZ-100MHZ C40 297 MARCONI DIFFERENTIAL DC VOLTMETER TF2606 extended horn and bell unit. 72 TEK Constant Amplitude Sig Gen 1908 350KHZ/50MHZ 6100 0-1100V C225 Sample units £39.00+ £2 p&p - £47.15 inc VAT each, 5 units £35.00+ £2 p&p -£42.55 74 MARCONI WIDE RANGE OSCILLATOR TF13700 10HZ-10MHZ. 300 RAS POLYSKOP SWOB1 BN 4244/2/50 0350 inc VAT each, 10 units £33.00 + £2 p&p - £40.25 inc VAT each. Sine and Square C95 Mee ie Moak NEW OSCILLOSCOPES, MULTIMETERS etc. EXTERNAL HORN Sample £7.50+£ 1 p&p -£ 10.35 inc VAT each, 5 units £6.75+ £ 1.50 80 WAYNE KERR AF Sig Gen 5121 10HZ-120KHZ Cb p&p - £9.49 inc VAT each, 10 units £6.37 + £1.50 p&p - £9.05 inc VAT each. 87 H.P. Pulse Gen 214A 10HZ-1MHZ @50 THIS IS A VERY SMALL SAMPLE OF STOCK, SAE or Telephone 89 EH PULSE GEN 139L 1KHZ-20MHZ Single/Double Pulse £200 for LISTS TERMS C.W.O. it export enquiries welcome. We find impossible to advertise all we stock. 99 TEK TIME MARK GEN 180 C40 Please check availability galore ordering. Carriage all units Please telephone, write or telex for further enquiries. Personal callers always welcome. 102 BONTOON 0 METER 260A 50KHZ-50MHZ £250 010 VAT to be added to Total of Goods 6 Carriage.

SPRINGFIELD HOUSE, STEWART OF READING TYSSEN STREET, 110 WYKENAM ROAD, READING, BERKS 8661 PL LONDON E.8. 2ND ea - ELECTRONIC EQUIPMENT CO. TEL NO. 01-249-5217 Telephone: 0734 68041 TLX: 8953906 EECO G Callers welcome 9 a.m. to 5.30 p.m. Monday to Saturday inclusive CIRCLE 56 FOR FURTHER DETAILS. CIRCLE 52 FOR FURTHER DETAILS.

84 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com NEW PRODUCTS

PERSONAL LOGIC ANALYSER Facilities for the troubleshooting use of front panel controls. of microprocessor systems are Specific areas of a program may incorporated into the PM3626 be explored by the four-level logic analyser from Philips. It is triggering system and the timing used to locate faults in a delays which can count up to 50 microprocessor system, both thousand clock cycles to hardware and software. The 32 - pinpoint a specific action. The channel instrument can be used instrument is operated through for logic state analysis, or up to menu selection on the screen 12 channels can be used for and multi -function keys. For timing analysis while the rest example it is even possible to are used for state. Maximum recall the colour coding of the sampling speed for accurate probe leads and thus save a lot timing can be set at up to of time referring to the 100MHz. instrument's manual. State For software bug -hunting, the displays may be chosen to give analyser may be fitted with a the information in binary disassembler for any of the decimal, octal, hexadecimal or reference data and compare which, according to Philips, is twelve most popular ASCII. with incoming data on the well below the cost of rival microprocessors. Interactive The analyser may be instrument. Each of the 32 instruments. It is also available software de -bugging is also extended by adding a non- channels may be examined to a for hire from Livingstone Hire possible by the use of a rom volatile setting module which depth of 1000 samples or four and from Instrumental Rentals. emulation module, plugged into retains up to eight preset channel to a depth of 8000. A Pye Unicam Ltd, York Street, the rom socket of the system configurations for the further option is an RS232C Cambridge CB1 2PX. under test. Programs may be instrument. Another non- interface card. patched to the target system by volatile memory option can hold The instrument costs £3285 EWW 208

MONOLITHIC COLOUR GRAPHICS PREAMPLIFIER A high resolution graphics industrial processes. The board ASCII characters and the high - controller combines many of the is compatible with the Acorn density text mode enables the An ultra -low-noise monolithic features usually found on much bus and includes full address use of 32 rows of 85 characters. preamplifier circuit is larger systems into a single decoding so that it occupies Character size and style, particularly suited to Eurocard. It has been only 32 bytes of the host including italics are all fully user microphone signal processing, specifically designed for computer's memory. It includes programmable and characters says CMS who are marketing industrial environments where 64K of onboard graphic may be scaled independantly in the SSM 2015 from Solid State the engineer needs reliability, memory. Eight colours with X and Y directions by up to 16 Micro Technology. The very low speed, and easy software inverse and flashing are times. Price? £299. Cambridge voltage noise performance is implementation. The board is available on a screen image 512 Microprocessor Systems Ltd, enhanced by a programmable. based around the Thompson by 256 elements with a 44a Hobson Street, Cambridge, input stage which allows overall EF9366 grraphics processor i.c. resolution of 5 to 8 dots. In CB1 1NL.. noise to be optimized for source and is especially suitable for black and white, 16 levels of EWW 210 impedances up to 4k52. The process control where the grey are available. An internal circuit has a bandwidth of ability to display text mixed rom includees a full set of 96 700kHz at a gain of 100 with from a variety of sizes and symmetical slew rates of 6V/us colours, combined with graphic and distortion of 0.007%. True symbols makes it easy to differential inputs and a high represent a diverse range of common -mode rejection of 100dB provide easy interfacing to balanced micropphone outputs, tape heads and single - ended devices. The SSM2015 is specified for commercial temperature ranges only and has a one-off price of £9.48. CMS (Distribution) Ltd, 26 Pamber Heath Road, Pamber Heath, Basingstoke, Hants RG26 6TG. EWW 209

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 ! 85

www.americanradiohistory.com NEW PRODUCTS

POTTING BY ULTRA-VIOLET MULTI -TASKING MICRO The of one rom to a As it stands, the Multi -Forth Rapid curing is claimed for the chiefly in their viscosities, addition BBC microcomputer can change rom, along with full fitting structrual adhesives developed making them more suitable for it into quite a different instructions and an impressive by Loctite for the encapsulation different applications. The low - computer; one that runs Forth 170 -page manual costs £40. of electronic components. The viscosity UV371 has good and is capable of executing Despite using the 16K rom as one -part adhesives are cured by penetration properties and is several different Forth economically as possible, David exposure to medium or high therefore good for coating and applications at the same time. Husband, who developed the intensity u.v. light in a matter shallow potting. Loctite UK, Multi -Forth 83 is a 16K eprom system, had to leave some of of seconds. Loctite estimate Watchmead, Welwyn Garden which may be plugged into a the refinements out. that in such operations as City, Herts AL7 1,113. spare 'sideways' rom socket A £40 disc added to the rom potting relay switches there is a EWW 211 within the computer. Depending program provides a de -luxe saying of 26% when compared on its position, it can be given a version which contains many with epoxy compounds. In higher priority than the Basic more source -code definitions addition the u.v. adhesives use rom and thus be controlled from and a large number of colour no solvents and have an Forth with Basic as an addition. and graphics commands. The indefinite pot life, making them The version of Forth, de -luxe version improves on the highly suitable for automation. latest Forth 83, is used. This is an already impressive tasking A secondary system for Forth 79 facilities, although the full curing ensures that even the improved version of many additions to the system is not yet finalized parts that the u.v. light does with - resident dictionary of command David Husband keeps adding to not reach are cured by the words*. In addition, Multi -Forth it. The disc includes a anaerobic action of the has been suit the demonstration program which adhesive. Different formulations tailored to BBC and has therefore divides the screen in five of the adhesive are suitable for of Basic windows; two are scrolling text different applications: for translated many the commands, for example the independantly, one displays a example UV365 is real-time clock, another an recommended for smaller graphics and sound commands, into Many of the oscilloscope -type display and component potting, sealing and Forth. operating system commands these all leave the larger encapsulation. It has a medium window free to enter and run viscosity and when cured can have been incorporated and all programs exactly as if there withstand temperatures from the 'star' commands may be used from within Forth. were not four other programs -55 to 175°C, and is resistant Especially suited for control running at the same time. to most kinds of chemical and Versions of Forth on rom enviroments, retaining full monitoring applications, with multi -tasking facilities are strength under the most multi -tasking enables the user to run a number of programs also available for the Electron, stringent of tests. Other simultaneously, transparent to The ZX Spectrum, The ZX81 adhesives in the series vary each other. Each task is placed and other computers. Skywave in a queue and the total length Software, 73 Curzon Street, of the queue can be up to 28 Boscombe, Bournemouth, BH1 programs. A task has its own 4PW. 32 -bit clock and can be EWW 213 PICOAMMETER scheduled to execute at a pre-determined time, controlled * a full description of the differences Model 485 picoammeter has Additional feature include fast directly by the user, or between Forth -79 and Forth -83 is in been upgraded over pevious autoranging, relative, controlled from within other the August edition of Byte. models by the addition of a differential, measurement, 100 tasks, forming an interactive decade of sensitivity and data point storage with interdependant suite of resolution. A GPIB version is minimum/maximum readings programs for such applications available to interface with held, and the ability to log the as robotics. At the simple level, MOTOR SPEED instrument controllers. All front current display. Digital printer output can be defined as CONTROLLER panel controls can be calibration can be performed a task which, when run leaves programmed through the over the bus. Keighley the computer free for normal Designed for the control of ZN411E interface bus. An optional Instruments Ltd, 1 Boulton use. Disc and tape can be run at electric drills, the from battery pack allows partable Road, Reading, Berks RG2 the same time on different files; Ferranti is equally suitable for operation for up to six hours. ONL. EWW 212 very useful in data logging. Up the control of a number of a.c. to four files may be open to motors including other power access at a time and block files tools, and domestic equipment. greater than 32K can be The controller offers 'soft start' maintained on disc. capability, precise control and The system is vectored and can work in reverse complete features may be redefined or with a built-in shunt regulator, the whole system may be the i.c. comes in an 18 -lead re -configured by redirecting the dual in -line package and will vectors. In addition, there is a operate from the a.c. mains standard 6502 assembler for supply, though it can be machine -code definitions and a operated on d.c. power as well. standard Forth screen editor Stocked by Celdis Ltd, 37 which is enhanced to allow the Loverock Road, Reading, Berks use of the cursor keys for RG3 lED. full -screen editing. EWW 214

ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com SINAD MEASUREMENT FOR CELLULAR RADIO

NEW Helper PML-1 SINADDER with Also available in the Helper psophometric weighting filter - the range of low cost instruments ideal instrument for cellular radio for mobile radio test and SINAD measurement and alignment. alignment: Includes all features the of the AUTOPEAK Modulation SINADDER Linear 5 automatic Monitor SINAD meter: True RMS SINAD measurements LINEMAN telephone control Linear 0-24 dB SINAD scale - line Transmission Test 12 dB centre scale Set/Intercom No frequency, null or level TONER II Tone Frequency adjustments to make: just connect Counter to the audio line and read SINAD DSR-100 Digital Squelch directly Reader True RMS voltmeter - 9 scales 10mV-100V fs P milt.- 1 sin:ebddpr RF -801 sensitive wideband RF Millivoltmeter Isolated 1 kHz test tone output Monitor loudspeaker Audio signal tracer mode

LYONS INSTRUMENTS LIMITED

Ware Road Hoddesdon Herts EN 11 9DX LYO N S Tel (0992) 467161 INSTRUMENTS Telex 22724 CL HOD G CIRCLE 45 FOR FURTHER DETAILS. Happy Memories

Part type 1 off 25-99 100 up

4116 200ns 1.25 1.15 1.10 4164 200ns Not Texas 4.45 4.15 3.95 2016 15Ons Like 6116 4.75 4.25 4.10 6116 150ns Low power 7.75 Call Call 6264 150ns Low power 23.65 Call Call VALVES 2716 450ns 5 volt 3.85 3.45 3.30 2732 450ns Intel type 4.75 4.25 4.10 High Quality 2732A 350ns 5.25 4.69 4.50 2532 450ns Texas type 3.85 3.45 3.30 Best Prices 2764 300ns Suit BBC 5.95 Call Call 27128 300ns Suit BBC 16.95 Call Call Large Stocks Z80A-CPU...£3.75 Z80A-PIO...£4.20 Z80A-CTC...£4.85 Rapid Delivery Low profile IC sockets: Pins 8 14 16 18 20 24 28 40 Pence 12 13 14 16 18 24 27 38

Soft -sectored floppy discs per 10 in plastic library case: 5 inch SSSD £17.00 5 inch SSDD £19.25 5 inch DSDD £21.00 5 inch SSQD £23.95 5 inch DSQD £26.35 Edicron

74LS series TTL, wide stocks at low prices with DIY discounts starting at a mix of just 25 pieces. Write or 'phone for list. Serving industry forover 25years Tel: (1)9612020 TIx:265531 Please add 50p post & packing to orders under £15 and VAT to total Access welcome, 24hr 'phone service on (054 422) 618 1-7 WesleyAvenue, London NW10 7BZ. Non -Military & Educational welcome, £15 Government orders minimum. Cable: Edicron London NW 10 HAPPY MEMORIES (WW) Gladestry, Kington Herefordshire HR5 3NY Tel: (054 422) 618 or 628

CIRCLE 17 FOR FURTHER DETAILS. CIRCI.E29F'o RFLRTIIF.RDE'l'AILS. ELECTRONICS & WIRELESS WORLD DECEMBER 1984 87

www.americanradiohistory.com SOME IDEAS NEVER SELL... but our new innovations do ! Crotech 'scopes are chosen for use throughout the electronics 11N\ industry and in education for their reliability and ease of use.

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The innovations.. * Component Comparator * Triple Output DC Source

p/us.. . * 20MHz Bandwidth * 2mV/div Sensitivity * 4Ons/div Timebase * TV Frame and Line Trigger * Add and Subtract * X -Ymode ... and very affordable at £297.00* For free details call: '(exc. VAT) Crotech instruments Limited 2 Stephenson Road, St. Ives, Huntingdon, Cambs. PE17 4WJ Telephone: (0480) 301818 CIRCLE 58 FOR FURTHER DETAILS.

TIME WRONG? MSF CLOCK is ALWAYS CORRECT - never gains or loses, SELF SETTING at switch -on, 8 digits shown Date, Hours, Minutes and Seconds, auto GMT/BST and leap year, larger digit Hours DATURR and Minutes for easy QUICK -GLANCE time, can expand to Years, Months, Weekday and Milliseconds or make a second - in -a -month STOPCLOCK, parallel BCD output for computer or alarm and audio to record and show time on playback, receives In the advertisement published in Rugby 60KHz atomic time signals, only 5x8x15cm, built-in antenna, 1000Km range, £79-70. GET the TIME absolutely RIGHT. the November issue the Small 60KHz RUGBY RECEIVER, as in MSF Clock, serial data output for Cases described as light grey are computer, decoding details, Basic listings, £25-80. Each fun -to -build kit (ready made to order) includes ALL parts, now being supplied in blue. The case, pcb, by -return postage and list of other kits. 19in Cases described as having CAMBRIDGE KITS 45 (WL) Old School Lane, Milton, Cambridge. Tel 860150. 'prodruding edges' are also available without these, other than those advertised at reduced prices. .- r RADFORD Audio Measuring Instruments, Audio Amplifiers, Loudspeakers and (í) DATURR Loudspeaker Components for the v LTD. professional and enthusiast Albany Park, Frimley Road, RADFORD AUDIO LTD. Camberley, Surrey GU15 2PL. 10 BEACH ROAD Tel: 0276 681 21 2 Telex: 858024 WESTON-S-MARE, AVON BS23 1AU TEL. 0934 416033

CIRCLE 51 FOR FURTHER DETAILS. CIRCLE 38 FOR FURTHER DETAILS.

ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com NEW PRODUCTS

BBC BASIC EXTENSION Other utility and language roms graphics commands. for the BBC Micro provide their Addcomm also incorporates special facilities through 'star' some Basic editing aids, commands. But Vine Micros' including a `bad program' Addcomm rom is different. The rescuer, a compacter, a new commands it offers are in character definer and a search - the form of additional Basic and -replace utility. Other keywords. commands give the user a Unlike standard Basic words string sorting routine, easier these are not converted into handling of text and graphics single -byte tokens by the windows and (though not for computer, so some care must purists) the freedom to jump be taken in using them. But out of For -Next loops without they give many new facilities, the usual consequences. notably in the graphics The Addcom rom is department: there are competitively priced at £28 commands for drawing circles including v.a.t. and carriage; it and ellipses, for filling areas is also available for the Acorn with colour and for scaling the Electron. Vince Micros, screen co-ordinates. In addition Marshborough, Sandwich, Kent there is a selection of Logo CT13 OPG, tel. 0304 812276. EWW 215

RS232 TO CURRENT -LOOP CONVERTER A converter to enable noise- current. The Remark model 65 immune communication over provides for 20 or 60mA current long distances with full protocol loops and can transmit or is available to connect to RS232 receive at uup to 9600bit/s. parts. It can convert in either Supplied with a reference direction and so can be used at manual the unit costs £100 or either or both ends of a less for bulk buyers. Advanced communications link. It may be Technology Maintenance Ltd, 2 SWITCHER I.C.S AND LAYOUTS used in half of full duplex and Norwich Road, Metropolitan Switching power supplies provide power line -hum may be operated in passive or Centre, Greenford, Middlesex operating at high frequencies suppression, dynamic current - active mode; when 'active' the UB6 8UB. can be easily adapted to provide limiting, over and under -voltage converter supplies the loop EWW 216 power at specific current and protection, soft start for the voltage values. Siemens supply itself, double -pulse produce four control i.cs for suppression, reference overload such supplies and have now protection and the facility for made it even easier to design external synchronization. them by the provision of card Siemens Ltd, Windmill Road, layouts with the position of all Sunbury -on -Thames, Middlesex components marked. The four TW16 7HS. circuits, TDA4700/ 14/ 16/ 18, EWW 217

IC LEG STRAIGHTENER

Simply push the integrated circuit through this device and the rollers will position the legs so that they fit i.c. holders or p.c.b. hole patterns. The machine is adjustable and can cater for different leg thicknesses. This particular model can cope with 0.3 and 0.6in pitch dual in -line devices but others are available for 0.4 and 0.9in pitches. Low cost and pins on i.cs are fraught with handy for small batches or for dangers and difficulties. Hionics those who do not have Ltd, Lower Quemerford Mill, automatic insertion machinery. Calne, Wilts SN11 8JS. Other methods of bending the EWW 218

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 89

www.americanradiohistory.com NEW PRODUCTS

LOGIC PROBE

A pen -sized, digital logic probe catch lOns pulses and that may be used on d.t.l, t.t.l. automatically stretch them to and mos circuitry comes from 50ms. It sets its threshold level OK Industries. The instrument automatically as a function of detects high or low logic levels the voltage found at the tip and and can indicate if the level is operates from the supply correct or incorrect. It can also voltage of the circuit being detect open circuit. Such a tested, from 4 to 15V. probe can often be used for Optionally an additional adaptor XY PLOTTER testing when the only allows the probe to be used alternative would be an from a supply up to 25V. OK A flat-bed xy plotter has a this way can be reproduced by oscilloscope and/or other bulky Industries UK Ltd, Dutton number of add-on options to the plotter. The light sensor can test equipment. The probe has Lane, Eastleigh, Hants S05 make it a versatile instrument. also be used to negotiate a frequency range from d.c. to 4AA. The Parfitt plotter is basically a mazes. On top of all this a drill 50MHz. The PRB-1 can also EWW 221 three -pen plotter that can be or router can be fitted and used instructed by a computer to to machine soft materials and draw anything from from drill (e.g.) p.c.bs. These add- complex geometric shapes and ons come as extras on top of patterns to graphs and the basic price of £270, the full electronic circuit diagrams. It kit of plotter, power supply, can use any of the three pens drill/router, , optosensor, scriber during its drawing program to and software on disc is £490. produce colour drawings. The Software on cassette is provided can be by a pens replaced in the I basics package. Aimed at scriber and the plotter' can then schools and colleges,it plugs be used to make scraper board directly into the user port of a pictures,on scribe copper for BBC micro and an optional etching. This in turn can be conversion makes it suitagle for replaced by a light sensor and the other widely used the instrument can scan a educational computers, RML picture to be displayed on a tv 380Zs. Parfitt Electronics Ld, 6 screen. A picture scanned in View Road, London N6 4DA. EWW 219

while internally it refreshes CRYSTAL CLOCKS PSEUDOSTATIC memory at a rate of 128 cycles/ 2ms. Access time is 200ns with RAM a cycle time of 330ns. Operating from a single supply A quartz oscillator is combined be supplied. For applications Low-cost dynamic ram chips rail of 5V, it consumes 330nW with a programmable on -chip requiring a data -rate generator, can emulate static devices by while active and 28mW on c.mos divider chain to produce two versions can be provided incorporating refresh counters standby. The price is claimed to up to 57 different output with base frequencies of 768 and multiplexers within the be 40% cheaper than the frequencies up to the crystal's and 96kHz which can produce package. The NEC uPD4168, a equivalent static ram. Available own frequency. A specific rates between 50 and 48 000 64K ram arranged as an 8Kbyte through Impulse Electronics frequency is selected by baud. Low power consumption memory, uses the standard 28 - Ltd, Hammond House, applying logic levels to the six and small size combine with the pin package and is pin - Caterham, Surrey CR3 6XG. control pins of the 16 -pin d.i.l. elimination of much external compatible with static rams, EWW 222 package. A selection of circuitry make these oscillators with crystal oscillator/dividers suitable for frequencies in the range many applications. Euroquartz which gives the equivalent power to a 60W 32.768kHz to 1MHz are Ltd, 5 Church Street, GAS -FIRED electric soldering iron. Tip temperature available as standard and a Crewkerne, Somerset TA18 SOLDERING IRON version without the crystal can 7HR. EWW 220 is adjusted to between 250 and A Christmas present for the 450°C. The gas resevoir is filled engineer who has everything is in much the same way as a gas this butane -powered portable cigarette lighter, and the pen - soldering iron. The Oryx sized tool has an igniter (i.e. Portasol works on a different flint) incorporated in its cap. principle from other gas - Apart from its portability the powered irons. There is no iron offers the elimination of flame during operation, the electrical damage to sensitive chemical energy in the gas being devices. Costs £17.90 inclusive. converted directly into heat by Replacement tips are readily means of a patented catalytic available. Greenwood converter in the iron's tip. The Electronics, Portman Road, rate of conversion is adjustable Reading, Berks RG3 1NE. up to the maximum setting EWW 223

ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com DEWSBURY ELECTRONICS

POCOMTOR AFR 2000 NOW AVAILABLE FOR £427 inc.VAT RTTY ALL MODE Special nanow band quadrature discriminator for all used LF shifts from'50 to t(tO Hz Simple and quick tuning with 16 line LED bar indication Extremely simple operating Current-saving 8 bit C-Mos microprocessor Development and manufactured in Switzerland

FEATURES AND APPLICATION: PocoMRNl 011-2Qttt RTTy ALL MODE - The POCOMTOR AFR-2000 RTTY ALL MODE DECODER allows the simple and easy writing of the PO, ea,Rox:c usual teletype codes as BAUDOT, ASCII (including 203 baud press service), ARO, FEC-Collective, FEC Selective ISITOR/AMTORI and the FEC procedure used for secret services, which differs from the usual CCIR recommendation 4762 The POCOMTOR AFR-2000 is a complete teletype decoder with built in new quadrature discriminator for automatic adapting and processing of the normal shift offsets of 50Hz to 1000 Hz. The POCOMTOR AFR-2000 is the first RTTY reception device on the consume area that fully automatically determines the received baud rate and synchronizes thereon, without being SPECIAL FEATURES: necessary as yet usual to test the baud rates and phase (Normal/Reverse) in question era troublesome way. It is now only required to call up the automatique -routine and after a short time for the signal Fully automatic recognizing of ARO, FECCollective and FEC reception of about 10 to 15 seconds the synchronization is reached and the text can be written. Selective ISITOR/AMTORI In the a ufe ARO/FEC, i.e. during synchronous character transfer (without start and stop bit) the built-in Fully automatic searching and synchronizing in Baudot mode intelligency finds out by itself whether it is an ARO or FEC signal, whereby it is additionally differentiated according to Baud rate and phase; indicetion of baud rate and between FEC-Collective and FEC-Selective. To balance signal phase moves there is a steady adoption phase of the microprocessor controlled sampling, as to pre -running characters and to afterrumng characters. Manual preselecting of all Baudot and ASCII speeds The technology of the POCOMTOR AFR-2000 RTTY ALL MODE DECODER corresponds to the highest Optimum microprocessor controlled signal reception with regueements. Its extraordinary prize/performance ratio wi not be readied in near future on the easy 16'0C° (sixteen thousand) samples per second and steady re - way. Choosing the POCOMTOR AFR-2000you take the most modem receiving device on the market. phasing on forward and backward run of signal Its for that you receive more and have to tune less it has never been thus easy to receive ratio teletype.

Dewsbury Electronics offer a full range of Trio Equipment always in stock.

We are also stockists of DAIWA-WELTZ-DAVTREND-TASCO TELEREADERS-MICROWAVE MODULES - ICS AMTOR-AEA PRODUCTS-DRAE-BNOS

BARCLAYCARD Dewsbury Electronics, 176 Lower High Street, Stourbridge, West Midlands. 111r1.)1 Telephone:Stourbridge 103841390063/371228, Open Monday thru Saturday. Instant H.P. subject to status, Access, Barclaycard and real money. Buy n nuh hover

CIRCLE 68 FOR FURTHER DETAILS.

HF ANTENNAS ,'"_447, EL R-Ö ALUE ECT * MODE; Full half wave operation. rYour * BANDS; Up to 4 spot gpSCIALIBT frequencies. * POWER; Receive to ' for SWITCHES 800W (PEP). Out of a very wide range of types, we show * SWR; Betterthan 1.5:1 some of the more popularly demanded ones. on channel. The full range currently stocked will be found in our latest free A -Z price & products list. Please mention this journal when contacting . Electrovalue. THE SMC TRAPPED DIPOLE ANTENNA PUSH BUTTON Miniature has been developed to satisfy the needs of commeúcal and military users. It is capable of 2 30 MHz as many as four spot frequencies each capable of MINIATURE TOGGLES, 7000 Series Single and Double Pole Changeover operation between and on - matching with a single 250V/2A, 120 V/5A. Single, double, standard accommodating many channels. Excellent and efficiency coaxial feed incorporation of a ferrite balun in a three and four pole configurations Latching and momentary is offered by the use of SMC H10 traps and the inc. Centre Off/On and biased. full half wave design. NB: Power absorbing terminating resistors are not employed. The antenna may two support masts, installation SMC SUDERS be deployed using one or )incorporating light duty masts) can be easily effected by two people in half an hour. Miniature SP and DP in portable CK WAVECHANGE with adjustable & Standard. stops. 1P/12 way, 2P/6W, 3P/4W, 1, 2 or 3 positions. 4P/3W, 6P/2W. Many other types such as for timing applications. and other special HF SSB TRANSCEIVER SWITCH KITS TM180 "PIONEER" HF SSB RA Shaft Assemblies up to 6 wafers. n TRANSCEIVER. 1.8-18MHz, 6 DP Mains switch. Screens; Spacers. channels 100 watts RF output ,A'rr measuring only 95(H) x 2401W) r7 x 310(Dlmm and weighing 6kg. May be operated as a base or mobile transceiver, comple- BRITAINS LEADING QUALITY COMPONENT menting our trap dipole and HW4 mobile aerials. Prices start FOR FREE 40 PAGE A -Z LIST at £700, making this unit not SUPPLIERS -SEND only very attractive but highly ATTRACTIVE DISCOUNTS -FREE POSTA6E6000 SERVICE & DELIVERY competitive. 28 St. Jude's Road Englefield Green MID ELECTRO ALUE LTD &MESS Egham, Surrey 01100 SOUTH MIDLANDS COMMUNICATIONS LTD. TW200HB bled( Orders SM HOUSE Telex: 264475. North: 680 Burnage Lane, Telex: 477351 SMCOMM G Tel: (0784) 33603. Phoned OSBORNE Manchester (061-432 4945). EV Computing Shop, 700 Welcome ROAD, TOTTON Tel: Totton (0703) 867333 Burnage Lane, Manchester (061-431 4866). SOUTHAMPTON SO44DN

CIRCLE 72 FOR FURTHER DETAILS. CIRCLE 71 FOR FURTHER DETAILS.

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 91

www.americanradiohistory.com 1000's OF OMPUTER F CALLERS-- THE ALADDIN'S CAVE Or COMPUTER AND ELECTRONIC EQUIPMENT' HOT LINE DATA OASE COMPUTER 'CAB' SOLID STATESWITCHES All in one quality computer Matchbox size solid state switch type IR D2402 cabinet with integral switched '' enables on off control of 240 V AC loads up to mode PSU. Mains filtering, and twin fan cooling. 600 watts, direct from your micro etc. Fully isolated © Originally made for the famous DEC PDPB computer THE DISTELFREE dial up data base 3-32 v DC input with zero voltage ORIGINAL OF CHARGE system costing thousands of pounds Made to run 24 switching. 1000's items off bargains Complete with data £&M + pp of stock and one hours per day the PSU is fully screened and will deliver a ON LINE NOW- 300 baud, full duplex CCITT tones, 8 bit massive +5v DC at 17 amps, +15v DC at 1 amp and -15v 250,000 other relays EX STOCK call for details. word, no parity. DC at 5 amps. The complete unit is fully enclosed with 01-679 1888 removable top lid, filtering, trip switch, 'Power' and 'Run' EX STOCK INTEGRATED CIRCUITS LEDs mounted on Ali front panel, rear cable entries, etc. in good used condition - supplied for 2732 EPROM SPECIAL fully guaranteed MAINS FILTERS etc. Units are but Cure those unnerving hang ups and data glitches caused 240v operation complete with full circuit and tech, man. 450ns £3.75, 350ns £4.00, by mains interference Give your system that professional finish for only 300ns £4.59 SD5A As recommended by 2)(81 news letter. matchbox £49.95 + Carr Dim. 19" wide 16" deep 10.5" high. EPROM SPECIAL size up to t000 watt load E5.95 Useable area 16"w 10.5 h 1 1.5"d. 2732 fully guaranteed L2127 compact completely cased unit with 3 pin fitted Also available LESS PSU, with FANS etc. Internal dim. 450ns 23.75, 350ns 24.00, 300ns 24.50 socket Up to 750 watts E9.99 19"w. 16"d. I0.5"h.E/9.fä. Carriagé & insurance £9.50. I Keep your hot parts L and LIABLE PRICE BARRIER SHATTERED ON 16' cooLwith our range of BRAND NEW professional cooling fans ETRI 99XU01 Dim. 92 x 92 x 25 mm. RGB CASED COLOUR MONITORS Miniature v fan complete with 240 equipment A from a finger guard £9.95. tii::: scoop purchase major London Hotel enables us to offer this special COULD JB-3AR Dim. 3" a 3" a 2.5" compact converted DECCA 100 COLOUR video TV at a super low price of £99.00!! Low very quiet running 240 v operation. NEW £5.95 enough to suit any budget!! Solid state modular construction, 16" high definition BUHLER 69.11.22. 8.16 v DC micro PIL tube, which eliminates convergence problems and our own special modification miniature reversible fan Uses a brushless results in 80 + column text definition and picture quality not seen on monitors servo motor for extremely high air flow, costing three times as much!! In fact we guarantee you will be delighted with this 10,000 almost silent running and guaranteed product, the quality has to be seen to be believed. Supplied complete and ready to hr life. Measures only 62 x 62 a 22 mm. plug Current cost £32.00. OUR PRICE ONLY direct to a BBC MICRO COMPUTER or any other system with a TTL RGB £12.95 complete with data. output. Other features include internal audio amp and speaker, compact MUFFIN -CENTAUR standard 4" a 4" x 1.25" dimensions only. 52cm W x 34 H x 24 D, auto degaussing circuit, attractive teak fan supplied tested EX EQUIPMENT 240 v at finished case, 30 day guarantee. C6.25 or 110 v at £4.95 or BRAND NEW 240v ONLY £99.00 + £10.00 CARR. 1000's fans at C10.50. of other Ex Stock. Also Call for Details Post 8 Packing on all fans C1.6 available unmodified complete with mod data (Mod costs less than £12.00) 110.00. I EPROM COPIERS SPECIAL 300 BAUD MODEM I FFE BUDGET RANGE Another GIGANTIC purchase of these EX BRITISH TELECOM, BRAND VIDEO MONITORS The amazing SOFTY 2. The "Complete Tool - NEW or little used 2B data modems allows US to make the FINAL kit" for copying, writing, modifying and listing At a price YOU can afford, our range of EX EPROMS of the 2516, 2716, 2532, 2732 REDUCTION, and for YOU to join the exciting world of data EQUIPMENT video monitors defy range. Many other functions include integral communications at an UNHEARD OF PRICE OF ONLY £29.95. Made to competition!! All are for 240v working with keyboard, cassette interface, serial and the highest POST OFFICE APPROVED spec at a cost of hundreds of standard composite video input. Units are i/o, modulator, parallel data UHF ZIF socket pounds each, the 28 has all the standard requirements for data base, pre tested and set for up to 80 col use on etc. ONLY E195.00 + h E2.50. BBC micro. Even where MINOR screen "GANG OF EIGHT' intelligent Z80 controlled business or hobby communications. All this and more!! burns MAY exist - normal data displays are gang programmer for ALL single 5v rail 300 baud full duplex CALL, ANSWER and AUTO modes unaffected. EPROMS upto 27128. Will copy 8 271288 in Full remote control Standard RS232 serial interlace I000's SOLO TO DATE typ. ONLY IN Internal in 12" KGM 320-321, high bandwidth input, and checking routines for rnIDIOT D PROOF CCITT tone standards NOW ONLY Built test switching up to 132 x 25 lines. operation. ONLY E395.00 +1)19 EJ.00. Supplied with full data £49.95 240v Mains operation will display columns Housed in attractive fully enclosed "GANG OF EIGHT PLUS" same spec. as Modular construction 1 year full guarantee Direct isolated connection Just 2 wires to comms. line brushed alloy case. B/W only £32.95 above but with additional RS232 serial inter- GREEN screen£39.95 face for down line loading data from computer Order now while stocks last. Carriage and Ins. £10.00 etc. ORLY£445.00 + PP E3.00. - 24" KGM large screen black 8 white monitor fully in light Data sheets on request. enclosed alloy case. ONLY 55.00ools,shops, clubs etc. 811 19M8 WINCHESTER DISK DRIVE Made in the UK by a subsidiary of the World's largest disk drive manufacturer. This BRAND NEW "end of line" unit offers an outstanding opportunity for the DATA MODEMS technically competent computer buff to add a MASSIVE 19 mb OF STORAGE to their computer system. Superbly constructed on a heavy die cast chassis the Join the communications revolution with .DRE 3100 utilises 3 x 8" plattens in a dust free cavity. All drive functions are our super range of DATA MODEMS with controlled by microprocessor electronics using an INTEL 8035 cpu and TTL prices and types to suit all applications ,support logic. Interfacing is via a comprehensive 8 bit TTL level bi directional and budgets!! command / status bus with superb status reporting and individual high speed Most modems are EX BRITISH serial i/o lines for separated clock and data etc. Many other features such as TELECOM and are made to the highest Average seek time ms, per v standard for continuous use and reliability. 35 512 bytes sector, +24 -24 and +5 DC supply, RS232 interfaces are standard to all our plug in card system, and very compact size of 19cm H x 21 cm W x 42 cm D etc. modems, so will connect to ANY micro etc. etc. make this item a real snip. with an RS232 serial interface. Units are BRAND NEW and BOXED and sold at a FRACTION of original cost DATEL 2B see SPECIAL OFFER centre of - hence unguaranteed. Complete with 150 page manual', circuits and this ad. MODEM 13A, 300 baud. Compact unit only applications guide. 2" high and same size as telephone base. 14" BRAND NEW Novex COLOUR type Standard CCITT tones, CALL mode only. Carriage £10.00 NC1414-CL. Many exacting features such Tested with data. ORLY E45.00 + P EC 50. ONLY £225.00 as RGB TTL and composite video input, MODEM 20-1, 75-1200 baud. Compact unit Suitable power supply unit - sold ONLY with drive £39.95. GREEN TEXT key, internal speaker and for use as subscriber end to PRESTEL, audio amp. Even finished in BBC micro MICRONET or TELECOM GOLD. Tested with PROFESSIONAL KEYBOARD OFFER colours. Fully guaranteed. data. £39.95 + PP £6.50. An advantageous purchase of brand new surplus allows a great OWERTY, full travel. OLYCarriagem Ifchirg rs. MODEM 20-2, same as 20-1 but 1200-75 chassis keyboard offer at fractions of their original costs. baud 199.00. ALPHAMERIC 7204/90 full ASCII 60 key upper, lower + control key, parallel TTL and ins on ALL videos £10.00 TRANSDATA 307A, 300 baud acoustic output plus strobe. Dim 12" x 6" +5 á -12 DC. E7í.50. coupler. Brand new with RS232 interface. DEC LA34 Uncoded keyboard with 67 quality, GOLD, normally open switches on £95.00 + PP 14.50. standard X Y matrix. Complete with 3 LED indicators á i/o cable - ideal micro DACOM DSL2123 Multi Standard Modem, conversions etc. pcb DIM 15" x 4.5" 12495 Carna r e on keyboards £3.00. SEMICONDUCTOR switchable CCITT or USA BELL 103 standard. V21 300-300, V23 75-1200, V23 1200-75 or ELECTRONIC 'GRAB BAGS' 1200-1200 half duplex. COMPONENTS Mixed Semis amazing value contents Auto answer via MODEM or CPU. CALL or include transistors, digital. linear. I 's tracs, ANSWER modes plus LED status indication. 66% DISCOUNT EQUIPMENT diodes. bridge recs., etc. etc. All devices Dim 2.5" x 8.5" x 9". BRAND NEW fully Due to our massive bulk purchasing programme which enables us to bring you the best possible new full spec with manu- guaranteed ONLY £267.00 + 991450. guaranteed brand bargains, we have thousands of LC.' s. Transistors. Relays. Caps. P C B s. Sub -assemblies. facturer's markings, fully guaranteed. DATEL 2412 Made by SE LABS for BT this Switches. etc. etc. surplus to our requirements. Because we don't have sufficient stocks of any two is for links at 50+12.95 100+15.15. part unit synchronious data in our ads. We are packing these items into the 'BARGAIN PARCEL OF A 1200 or 2400 baud using 2780/3780 one item to include all TTL 74 Series A gigantic purchase of an of components at giveaway to be worth protocol Many features include Auto answer, LIFETIME. Thousands prices, Guaranteed "across the board" range of 74 TTL series at least what you pay. by weight. 2 or 4 wire working etc. etc. COST OVER 3 times Unbeatable valuell Sold IC's enables us to offer 100+ mixed £800. OUR PRICE E115.00. 2.5kIsE4.25 + pp £1.25 5kIs£5.90+£1.80 "mostly TTL" grab bags at a price which two DATEL 4800, RACAL MPS4800 high speed 10kIs 110.25 + pp £2.25 20 kls £17.50 + £4.75 or three chips in the bag would nnormally condition. 1255.00 CARR Elm cost to buy Fully guaranteed all I.C's full CES PLUS VAT / spec. 100+ Ufa 200+ /12.30 300+ 119.50 ici t All paces quoted are for U.a Mainland, paid cash with order in Pounds Stirling PLUSVAT. Minimum ordervalue£t00, Minimum Credit : Card order£ /0,00. Minimum BONA FIDE account orders from Government depts., Schools, Universities and established companies ;Jam Where post and packing not indicated please ADD £ 1.00. + VAT Warehouse open Mon-Fn 9.30- 5.30. Sat 10.15- 5.30 We reserve the right to change prices andspecifrcations without notice. Trade, Bulk and Export enquiries welcome. 32 Biggin Way, Upper Norwood, London SE19 3XF 1 % j1 r- _ -i Ì jjIii r Telephone 01-679 4414 Telex 27924 1 CIRCLE 80 FOR FURTHER DETAILS. 92 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com SRS - PRINTERS - PRINTERS -PRINTERS PRINTERS -PRINTERS - PRINTERS - PRI SUPER DEAL? NO - SUPER STEAL!! GE MODEL r GF TERMIPR/NTER The FABULOUS 25CPS TEC Starwriter 30 RANDoW Al ONLY £4 +VAT-----¡7 Made to the very highest spec the TEC Starwriter FP1500.25 features a heavy duty die cast chassis and DIABLO type print mechanism giving A large purchase of these stand alone superb registration and terminal units offers an EXTREMELY LOW print quality Micro- S A massive purchase of these desk top PRICE for a professional printer for direct processor electronics Or printer -terminals enables us to offer you offer full DIABLO/OUME connection to your micro. The printer has a a interface with these quality 30 cps printers at a SUPER command compatability fraction standard RS232 serial LOW PRICE against their original cost of Of its or 110, 200 and 300 and full control via CPM Words ar etc¡Mal Cost switchable rates of over £ 1000. Unit comprises of full OWERTY. Many other features include bi directional baud. Upper and lower case characters electronic keyboard and printer mach with printing, switchable 10 or 12 pitch. full width 381 mm paper handling will upto are printed by a matrix head with charac- print face similar to correspondence quality 163 characters per line friction feed rollers for single sheet or continuous paper, ter widths up to 132 columns. Unit accepts typewriter. Variable forms tractor unit internal butler, standard RS232 serial interlace with handshake. standard fan fold sprocket fed paper from enables full width - up to 13.5" 120 column Supplied absolutly BRAND NEW with 90 day guarantee and FREE daisy wheel paper, upper - lower case, standard RS232 4" to 9.5". Many other features such as serial interface, internal vertical and and dust cover Order NOW or contact sales office for more information. keyboard, auto Optional extras RS232 data cable £10.00. Tech manual £7.50 Tractor feed numeric keypad, electronic horizontal tab settings, standard ribbon motor and FREE floor stand. adjustable baud rates quiet operation plus £140.00 Spare daisy wheel £3.00 Carriage & Ins (UK Mainland) £10.00. on/off Supplied in good S/H working condition - many other features. Supplied complete with manual ONLYE95.00 with manual. Guaranteed working E/30.00 or complete untested Eíí.00. optional floor stand £12 50 AV 6INS 510.00 SUPER PRINTER SCOOP CARRIAGE Carr & Ins £ 10.00. 2 EXTEL TELETYPE ASR33 7 y CENTRONICS 739- PRINTERS EX NEWS SERVICE compact, quality I/O TERMINALS ' 1 9RÑW The "Do Everything Printer" at 3 price that will built 50 column matrix printer, type AE11. FROM E 195 + CAR. + VAT repeated NEVER be Standard CENTRONICS Unit operates on 5 BIT BAUDOT code Fully fledged industry standard ASR33 data parallel interface for direct connection to BBC, terminal. Many features including ASCII ORIC. DRAGON etc. Superb print duality with lull from current loop, RS232 or TTL serial ul,terfaces. May be connected direct to keyboard and printer for data I/O auto data pin addressable graphics and 4 type fonts plus 110 internal PROPORTIONAL SPACED micro, or comms receiver via filter detect circuitry. RS232 serial interface. DEFINITION simple reader for iHIGHMODE for WORD PROCESSOR applications. 86132 network to enable printing of most world baud, 8 bit paper tape punch and roll plus off line data preparation and ridiculously ' columns, single sheet, sprocket or paper handling wide NEWS, TELEX and RTTY services. from DISPLAY ELECTRONICS cheap and reliable data storage. Supplied in much more. Available ONLY Supplied in tested second hand at the ridiculous price of Ma r£19H.00 + VAT Complete with condition good condition and in working order with full manual etc. Limited quantity -Hurry wide stocks last. 50 and 75 baud xtals, data sheet and Options: Floor stand£ 12.50 + VAT ONt. large A Options. Interface cable (specify) for BBC, ORIC, paper roll. ONLY E49.95. KSR33 with 20ma loop interface£ /25.00 way £12 5). Dimensions 15" D x 5" H x 10' W ' 9 DRAGON or CENTRONICS 36 pig Spare ribbon Sound proof enclosureE25,00 + VAT £3.50 each BBC graphics screen dump utility program £8.60. CARRE6.00 Spare paper rolls £4.50 each rn...n. In 10.IO*VAT 20,000 FEET OF ELECTRONIC AND COMPUTER GOODIES ENGLAND'S LARGEST SURPLUS STORE- SEEING IS BELIEVING!!

EX STOCK D.C. POWER SUPPLY SPECIALS DUAL DISK DRIVE/ Experimentos PSU Ex-GPO. All silicon electronics. Outputs give -5v (S. 2 amps +12v @ 800 ma -12v @ 350 ma and 5v floating @ 50 ma. WINCHESTER CASES DEC Dim 160 x 120 x 350 mm. All outputs are fully regulated and shot circuit proof. Very smart, fully enclosed case unit Supplied in NEW or little used condition. Complete with circuit. 515.50 +E2.50 PP custom made to accept two full CORNER FARNELL 5 Volt 40 amps. Type number G6 -40A. This miniature switching PSU height 51/4" floppy disk drives or two PDP 1140 System comprising of CPU, 160mm wide 175mm high yet a massive 40 measures only deep and 90mm delivers 51/4" winchesters such as the 124K memory + MMU 16 line RS232 amps!! Fully regulated and smoothed with over voltage protection etc. 120 or 240 RHODIME R0200 or TANDEM interface, RPO2 40 MB hard disk drive, volts AC input. BRAND NEW and boxed with circuit at a fraction of the Supplied series etc. An internal switched TU10 9 track 800 BPI Mag tape drive, dual current list price. ONLY EI30.00 +53.00 CARR 6 INS. mode PSU supplies all the required rack system, VT52 VDU etc. etc. Tested LAMBDA LMCC5V BRAND NEW 240 v AC input with 5 volts DC as 8 to 10 amps and running 53750.00 voltages to in fully regulated output. Completely enclosed unit measures only 9" x 4" x 5".529.99 to enable you plug your drives and go!! BA11-MB 3.5" Box, PSU, LTC £385.00 LAMBDA LMCC5V 110 v AC input with 5 volts DC at 8 to 10 amps fully regulated features include mains filter, DH11-AD 16 x RS232 DMA output Slightly smoke damaged, hence ONLY E10.95. Other interface £2100.00 internal cables with standard drive DLV11-J 4 x PERIPHERAL SYSTEM SUPPLY. Runs almost any system. Fully cased unit supplied EIA interface £310.00 connectors, space for internal PCB, DUP11 Sych. Serial data i/o £650.00 in a band new or little used condition. Outputs give 5v @ 11 amps "+' 24v @ 4 amps. standard fan cut out and mounting, D0200 Dilog - multi RK All outputs are crowbar protected and the 5 volt output is fully regulated. Fan cooled. controller E495.00 tested with circuit 555.00 +51.50 CARL air filter. Overall dimensions Supplied DZ11-8 8 line RS232 mux board £650.00 1000's of other POWER SUPPLIES EX STOCK - CALL SALES OFFICE FOR 28 cm W x 30 cm D x 19 cm H LA36 Decwriter EIA or 20 ma loop £270.00 DETAILS. ONLY £55.00 + £6.00 CARR. LAXX-NW LA180 RS232 serial interface and buffer option £130.00 LAX34-AL LA34 tractor feed £85.00 MS11-JP Unibus 32 kb Ram £80.00 MS11-LB Unibus 128 kb Ram £450.00 DISK DRIVE SPECIALS AMBASSADOR MS11-LD Unibus 256 kb Ram £850.00 MSC4804 Qbus (Equiv MSV1 1-L) Floppy Disk Drives. Telephone Systems 256 kb £499.00 SIEME NS FDD-100.5 51/4" 40 track single sided. Ex new equipment tested, guaranteed PDP11 /05 Cpu, Ram, i/o, etc. £450.00 working. Complete with data 575.00 Limited quantity of these micro- PDP11/40 Cpu, 124k MMU £1850.00 SHUGART SA400 5'/á" 35 track, single sided, Ex equipment, guaranteed processor controlled 2 line plus 4 RT11 ver. 3B documentation kit £70.00 working 555.00 extension telephone systems. RKO5-J 2.5 Mb disk drives £650.00 KLBJA PDP 8 async i/o £175.00 SHUGART SA800, SA850 8" drives plus spares EX Stock call for prices. Comprising of compact CPU unit and MI8E PDP 8 Bootstrap option £75.00 Hard disk drives. four special telephones. Via simple VT50 VDU and Keyboard - each of the four Large quantities of HARD DISK drives currently EX STOCK including: push button controls current loop - £175.00 DRE series 30 mb Front Load for DEC, NOVA etc FROM £795.00 phones can ORIGINATE, HOLD or VT52 VDU with RS232 interface 5250.00 DIABLO 44/DRE 4000 A, B 5+5 mb cartridge drive FROM £995.00 TRANSFER calls to and from each CDC HAWK 5+5 mb cartridge new FROM extension. Other features include bell drive as condition £795.00 1000's of EX spares for DEC DEC STOCK CDC 9762 80 mb RM03 compatible FROM 52900.00 control, internal intercom, redirect, full PDP8, PDP8A, PDP11 systems & PERTEC D3422 5+5 cartridge drive FROM 5495.00 LED status indication, simple 4 wire peripherals. Call for details. All types of Large quantities of spares and controllers available for S100, DEC, HONEYWELL, DATA connections etc. Supplied in tested Computer equipment and spares wanted GENERAL. Call sales office for details. little used condition with full data. for PROMPT CASH PAYMENT. IN HOUSE disk drive refurbishing service - call for competitive quotations!! ONLY £250.00 + 56.00 CARR. 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 usa call for your spare part -77 .e requirements. Stock changes almost daily. Don't forget, ALL TYPES and QUANTITIES of electronic surplus purchased for CASH

ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com kK k * *kK* * *Ito Iq * ,s a* 1/PP BUSINESSI]IIF1SN SYSTEMS LTD a_aq /C %** MAPLE /CE 56, DRIVE, EAST ßRINSTEAD, WEST SUSSEX, RHt9 3UR ** 0 The PC -16 16-bit computer provides PERFECT COMPATIBILITY with the IBM PC/XT range. The motherboard can be supplied in two versions for stereoscopic conveneince. The 'N' version has no memory on board and the 'B' version with space for 64 to 256K RAM. Addition of the Memory Expansion Card provides a further 64 to 512KB of RAM. BASIC FEATURES INCLUDE: * 8088 CPU operating at 4.77 MHz * RUNS MS/PC-DOS & CP/M 86 * Provision for 8087 co -processor * READS & WRITES IBM-PC format * Four DMA channels * Accepts IBM-PC Peripherals * Three TIMER channels on board * Up to 256K RAM ON BOARD * 8 EXPANSION SLOTS SYSTEM -5 PC16 (B/3) - PRICE £1599 - Main computer employing 'B' board with 128K on board (upgradeable to 256K on board) PLUS Colour/Graphics adaptor providing signal capable of running monochrome displays on RGB output for full colour. Multi I/O card, providing floppy drive controller for two drives, one parallel port, one serial port, one games port with batter backed clock calander. RAM extension card for 512K. Two DS/DD floppy drives. 83 -key keyboard. All complete, built & tested in case with power supply together with Concurrent (multiuser, multitasking)CP/M,CCP/M manual, Basic manual and computer operations manual - ready to run!

MOTHERBOARD 'B', 8 -slot, 14in RGB HI-RES MONITOR (64odots WINCHESTER DRIVE 12MB £815 DRIVES - MEGABYTES FOR 128K £449 x 300 lines) £389 IBM COMPATIBLE KEYBOARD (83 MICROPOUNDS! MOTHERBOARD 'N', 8 -slot £329 12in HI-RES GREEN MON £89 key) £89 5" Height 500KB 40/80 £119 MULTIFUNCTION card with 128K 64K RAM EXTEND MODULE £59 KEYTRONIC 5150 K/BOARD £175 5" Height 1MB 40/48 £125 (expandable to 256K) one PLL-port, DS/DD FLOPPY DRIVE (500 KB KEYTRONIC 5151 K/BOARD £210 5" Height 1.6MB 40/80 £159 one SER -port (2nd option) Clock/ unformatted £175 SWITCHING POWER SUPPLY ....£105 5" Height 2MB 40/80 £199 Calendar with backup £259 WINCHESTER DRIVE ADD SERIAL PORT KIT £23 5" Height 500KB £119 MONOCHROME adaptor with CONTROLLER £425 FLOPPY DRIVE CONTROLLER ...£109 3" Height 1 MB £125 printer port £239 512K RAM BOARD - comes with 8" Full Size 1.6MB £309 MULTI I/O CARD - one pII, one 128K RAM installed fully IBM 8" Size 1.6MB £282 serial port, one games port, floppy compatible £299 HR 521 Height 12.75 MB Hard Disk drive controller, clock calender with unformated £492 battery backup £299 All brand new, boxed, with built in controller - standard power requirments. Full documentation and technical details. Add 15% VAT to all prices given. Remember, VAT is also applicable on carriage at 15%. Terms ONO. DEALER ENQUIRES WELCOME. FOREIGN enquiries if possible by telex please. However, French & German speaking staff at your disposal. MONEY BACK GUARANTEE. SEND £1.00 for our latest catalogue of over 3000 items, computers, peripherals, consumables, robotics, etc etc. *** TEL: (0342) 313427.716656.24631/2 TLX: 957547 ** CIRCLE 76 FOR FURTHER DETAILS. Hitachi Oscilloscopes the highest quality from £299 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 range that repre- sents the best value for money available anywhere. V-212 20MHz Dual Trace V-209 20MHz Mini -Portable (illustrated) V-509 50MHz Mini -Portable V-222 20MHz Dual Trace V -1050F 100MHz Quad Trace V -203F 20MHz Sweep Delay V-1100 100MHz DMM/counter V -353F 35MHz Sweep Delay V -I34 10MHz Tube Storage V-422 40MHz Dual Trace VC-6015 10MHz Digital Storage V -650F 60MHz Dual Timebase VC-6041 40MHz Digital Storage Prices start at £299 plus vat (model illustrated) including a 2 year warranty. We hold the complete range in stock for immediate delivery. For colour brochure giving specifications and prices ring (0480) 63570 Thurlby-Reltech, 46 High Street, Solihull, W. Midlands, 691 3TB CIRCLE 79 FOR FURTHER DETAILS.

Lynwood GD1 VDUs: Intelligent Green micro controlled, SIBINDERS Quick, neat and easy! RS232, printer port, 101 key k/b. Full Video enhancements. ONLY £149+ £15 P&P (S/H) Ifs so easy and tidy with the Easibind binder to file your copies away. Each binder is designed Burroughs MT686/7/TD710: Intelligent Green 12" VDU with to hold six issues and is attractively bound and blocked with the WIRELESS WORLD logo. 3 Price U.K. £4.30 including postage, packing and V.A.T. micros and 64K store. RS232. Programmable...Only £199 Overseas orders add 35p per binder. new or £149 S/H + £15 P&P Nat. Giro No. 5157552. Please allow 3/4 weeks for fulfilment of order. Videcom Apollo VDUs: Stylish 15' Green Z80 controlled e Payment by ACCESS/BARCLAYCARD/VISA. Send coupon below detailing credit card no. and VDU with printer port and lots of very advanced signature. features. Only £399newor £249 S/H £15 P&P Why not place your order now? Send the completed coupon below with remittance payable to: Centronics 306 Line Professional Easibind, 42 Hoxton Square, London N1 6NS printers: fast (120 cps), superb quality 80 column printer. Parallel i/f ONLY £99+ ell R £15.00 P&P Form WIRELESS WORLD--5. Computhink Act 800 Computer system. Dual floppies (2.4Mb) and lots of Order t business software ONLY £1200. I enclose P.O./cheque value for binders Diablo 630 Daisywheel prInter. OEM i/f NEW £599+ £15 P&P Years required Diablo Hitype 2 Daisywheel, Tractor unit, S/H £15 P&P IBLOCK LETTERS PLEASE £399+ Name Calcomp 565 Drum Plotter, lOthou steps ONLY £450+ £10 P&P Address BECKENHAM PERIPHERALS LTD Callers welcome SAE for LIST 01-466 5582 Date Registration No.735718 by appointment and enquiries 34 Rodman/ Road, Bromley Kent BR1 3JL CIRCLE 74 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD DECEMBER 1984

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DISPLAYED APPOINTMENTS VACANT: £ 19 per single col. centimetre (min. 3cm). Advertisements accepted LINE advertisements (run on): £4.00 per line, minimum £25 (prepayable). up to 12 noon Friday Nov. BOX NUMBERS: £5 extra. (Replies should be addressed to the Box Number in the 30th for Jan. Issue. advertisement, c/o Quadrant House, The Quadrant, Sutton, Surrey SM2 4AS). subject to space available PHONE: LUCY O'SULLIVAN, 01 661 3033 (DIRECT LINE) 1 Cheques and Postal Orders payable toBUSINESSPRESSINTERNATIONAL LTD. and crossed.

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£7,0OO-£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 Encineers and Managers * For free professional guidance: Call 076 384 676 (till 8pm most evenings) or send your C.V. (no stamp needed) to: ELECTRONIC COMPUTER AND MANAGEMENT APPOINTMENTS LIMITED (1926) The Maltings, High St., Burwell, Cambridge. CB5 OMB. Freelance Engineers If you would like to enjoy the very high earning levels and variety of work associated with freelance employment, then talk to us about our highly competitive rates for long and short term contracts with our many clients in the South of England. We are keen to hear from both established Contract Engineers and those contemplating entering this highly lucrative field for the first time where your earnings could exceed Some of the interesting and highly rewarding assignments that we have currently on offer include: * £30,000pa. * UHF and VHF Design Technical Writers for radio communications applications. Preparing manuals for process control and communications systems etc. * Test Engineering * Power Supply Design Development of I.E.E.E. Bus test systems for digital and R.F. measurement. Specialising in Switch -mode or High Power systems. * Coral 66 Software Design * Digital/Analogue Design micro processor hardware. for message switching applications. of based TO FIND OUT MORE and to obtain an early interview, please * Trials Engineering telephone JOHN PRODGER in complete confidence on Mathematicians; Analysts; Performance Evaluators; HEMEL HEMPSTEAD (0442) 47311 during office hours or one of Weapons Systems Engineers; all for defence applications. our duty consultants on HEMEL HEMPSTEAD (0442) 212650 evenings or weekends (not an answering machine). We also have many clients Alternatively write to him at the address below. offering excellent career opportunities at all levels of engineering, sales and management Executive Recruitment Services if; THE INTERNATIONAL SPECIALISTS IN RECRUITMENT FOR THE ELECTRONICS. COMPUTING AND DEFENCE INDUSTRIES 25-33 Bridge Street, Hemel Hempstead, Herts., HP1 lEG. (2783)

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 95

www.americanradiohistory.com Appointments AUDIO ENGINEERS Join a small dynamic team where your contribution will be recognised! Audix design and manufacture professional CUT THIS OUT! audio communication systems and Clip this advert and you Can Stop hunting for your next equipment for radio/T.V. broadcast studio appointment. We have a wide selection of the best applications. We are involved in a major appointments in Digital, Analogue. RF. Microwave, Micro- and successful development programme processor. Computer. Data Comms and Medical Dec tronics and we're here to serve your interests. which is leading to an increasing demand Call us now for posts in Design, Test, Sales or Field for our products. We are therefore Service, at all levels from £6.000-£16.000. expanding our Project Engineering, Test and Development sections and have a `Technomar& numbeer of challenging vacancies for Frqutrrnn 1- Ire lama) R ' ru:t,m'nt young self motivated engineers: 11 Westbourne Grove, London W2. Tel 01229 9239- ,1935: Project Engineering Manager To manage a small team responsible for ensuring SERVICE INDUSTRIES LIMITED of that all major projects are engineered and supplied Lahore, Pakistan requires for the proposed in accordance with tender specifications. The engineering complex for manufacture of mobile, position involves liaising with customers and portable and fixed station communications production departments, special engineering and equipment the services of a Pakistani occasional supervision of installation and national commissioning. Previous experience of professional post -graduate electronic engineer with at least audio engineering is essential. five years experience. Age less than 35 years. He is expected to advise on the planning, Project Engineer designing and manufacturing of To be responsible for all engineering aspects of communications equipment. Annual salary will major projects from liaison with customers to be above Rs. 100,000 along with benefits. equipment commissioning. Visits to installation sites both within the U.K. and overseas will occasionally be Please send your latest photograph with resume necessary. Previous experience of professional audio by 15th December 1984. engineering is essential and it would be SERVICE INDUSTRIES LIMITED advantageous to have some knowledge and 80-E/1, Gulberg-3 Lahore -11 (Pakistan) ,27,,:x, experience of microprocessors. Senior Test Engineer Capable of system test of complex microprocessor based mixing consoles and communication systems. Occasional visits to client's studios and TECHNICIANS commissioning of systems may be necessary. Advanced Development Engineers Telecommunications Technology We require both senior and junior engineers who have some digital experience, together with a good appreciation of analogue techniques. Experience Technicians at the Foreign and Commonwealth Office have wide-ranging with Z80 microprocessors would be an advantage. responsibilities and can make full use of comprehensive and unique facilities. There are also good promotion prospects and the opportunity, in some cases of service overseas. Software Engineer/Trainee We have vacancies at Hanslope Park, (Near Milton Keynes) for technicians to This post would ideally suit a young electronic work on the installation, maintenance and other work associated with HF com- munication equipment, VHF, UHF and microwave links and associated test engineer who has a special interest in software equipment; teleprinters, telephone subscribers' apparatus PMBXs, PAXs, design. Experience with Z80 microprocessor would PABXs, and ancillary equipment including that using analogue and digital tech- be an advantage however specialist training courses niques and voice frequency telegraph. can be provided Applications should normally have 4 years' relevant experience (7 years for more senior posts). To be considered you will need to possess ONC in Engineering, Mechanical Engineering, Electrical Engineering or Electronic Engineering, or an equivalent Development Technician City and Guilds Certificate, or another equipvalent qualification such as an Required to assist in the design, assembly and test appropriate TEC or SCOTEC certificate. of breadboards and prototype PCBs. The post would Ex -service 3 personnel who have had suitable training and at least years' appro- a young engineer who has priate service (as Staff Sergeant or equivalent) will also be considered. suit previously worked Salary will rise from a minimum of £6512 pa to a maximum of £9009 pa for the typically as a test or service engineer. From this Junior Grade and from a minimum £8757 pa to a maximum of £9998 pa for the position there are opportunities for rapid promotion Senior Grade. Starting salary in the Junior Grade may be above minimum for into other departments within the company. those with additional relevant experience. Annual leave on entry is 4 weeks 2 days. For further information on these appointments Relocation assistance may be available please telephone Mrs J. Lawson on 0799 40888 or Hours: 42 hours per week. write enclosing your C.V. to:- The Foreign and Commonwealth Office is an Equal Opportunities Employer. Please apply for an application form, quoting reference TT/06/84, and stating the grade you wish to be considered for. The closing date is 6 January 1985.

Recruitment Section, Foreign and Commonwealth Office, Hanslope Park, Hanslope, Milton Keynes MK19 7BH audix Foreign and Commonwealth Office. Audix Limited Station Rd., Wendan Saffron Walden (2784) Essex (2767)

96 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

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BORED ? Then change your job! t t 1) TEST ENGINEERS with Dolby good Analogue/Digital experience to test and fault Dolby Laboratories Inc. manufacture and market Audio Noise Reduction equipment which is find. Complete automatic test used by major recording companies, recording studios, the film industry and broadcasting equipment. C. £10,000 authorities throughout the world. Middx/Bucks/Berks 2) AUDIO/VIDEO Due to increased sales and the introduction of new products we have the following vacancies:- EQUIPMENT. Enquiries at all levels required to service sophisticaped TV and related Electronic Test Technicans (£135 pw NEG) We broadcast equipment. To £12,000 + car. Berks/Middx. need people educated to HNC level (or equivalent) with the 3) MINIS AND MICROS potential to develope test fault SYSTEMS repair engineers and finding skills (to required for work on Z80 component level) in a semi -automated test environment. based graphics systems. Field prospects. C.£8,500. Hants/Essex. 4) DRAFTSMEN - PCB/ Electronic Test Engineer (£8000 pa NEG) We need Electro mechanical cable experienced Test Engineers educated to HND to equivalent forms. Chassis cabinets. All areas. to £12,000. level who demonstrate a practical knowledge of Analog Hundreds of other Electronic and Computer vacancies to £12,500 testing and rapid "trouble -shooting" to component level. Phone or write: Roger Howard, C.Eng., M.I.E.E., M.I.E.R.E. For further information contact: Sarah Kennedy, Dolby Laboratories Inc. 346 Clapham Road, London SW9 CLIVEDEN CONSULTANTS 92 The Broadway, Bracknell, Berkshire 9AP. 01-7201111 Tel: 0344 489489 11640) (2758) CLIVEDEN

ELECTRONIC TECHNICIAN MIMI1:1 INTERESTING WORK REPAIRING, MANUFACTURING AND DEVELOPING ELECTRONIC FLASH EQUIPMENT FOR A LEADING PHOTOGRAPHIC Test Engineers DISTRIBUTOR IN CENTRAL LONDON. Applicants should have a knowledge of basic electronics to City & Guilds standard but microwave communications systems experience in this field is not essential. A driving licence would Wells, Somerset be an advantage.. Salary negotiable Telephone Nigel Fielden on If you have a thorough knowledge of functional testing of microwave elec- 01.833 4737 for an interview. tronics sub -assemblies, units and systems, then we can offer attractive career (2768) opportunities at Wells in Somerset. We are the Communications Division of Thorn EMI Electronics Limited and QUEEN MARY COLLEGE have played a leading role in developing the technologies on which modern (University of London) communications systems depend. ELECTRONICS Working in a development and production environment, you will be involved with microwave systems for civil applications, currently covering frequencies TECHNICIAN- up to 20 GHz. The post is available with the Particle These opportunities would suit electronics technicians with experience in Physics Research Group, and is funded by an SERC rolling grant for microwave testing, although college leavers who have received training in an initial period of 3 years. The group microwave systems as part of their course could also be considered for some is carrying out experiments within international collaborations at CERN, of the more junior posts. Geneva, Switzerland. As a leading high technology company, career development opportunities are The person appointed should posses at least an HNC and have had excellent with the potential of further developing your knowledge and previous practical experience in experience. Electronics. He will be based at Queen Mary College, but will be Attractive salaries and benefits include an active sports and social club and expected to spend time both at CERN and at the Rutherford Appleton free life assurance. Laboratory. Oxfordshire. The work will be closely associated with the Please 'phone or write for an application form quoting Ref. development of new fast time - EWW/385 to Mr. F. M. Taylor, Assistant Personnel Manager, digitising and charge sensitive analogue techniques for particle Thorn EMI Electronics Limited, Communications Division, detectors. The data acquisition Wookey Hole Road, Wells, Somerset BA5 1AA. Tel. Wells system is computer controlled. Novel techniques using UV lasers and fibre (0749) 72081. Ext. 227. optics will also be implemented. The successful candidate will be encouraged to pursue original ideas. The initial salary will be within the range £6581 to 987 per annum depending on agef and experience plus £1250 London Weighting. Letters of application giving age, experience and qualifications and the THORN EMI Electronics names of two referees should be sent as soon as possible to Mr D.R. Stone, Physics Department, Queen Mary College. Mile End Road, London, El Lm 4NS. (2776) Closing date: 7 December 1984 (2777)

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 97

www.americanradiohistory.com Appointments I.L.E.A. Learning Resources Branch Television and Publishing Centre, AUDIO DEVELOPMENT ENGINEER Thackeray Rd, London SW8 DUE TO EXPANSION, A VACANCY EXISIS IN Television Engineer (MG 10) OUR DEVELOPMENT DEPARTMENT, WHICH Salary range £7470-£9432 plus £1347 London Weighting WILL INVOLVE ALL ASPECTS OF DESIGN Allowance, and an irregular hours allowance of £228. FROM CONCEPT TO PRODUCTION. THE The Mobile Video recording Section, which is equipped to broadcast APPLICANT SHOULD BE QUALIFIED TO standard, makes observational classroom recordings for teacher education. A DEGREE LEVEL, AGED 21-25 AND HAVE A television Engineer is required to join a technical team of 8 for operational KEEN INTEREST IN MUSIC and maintenance work involving rigging and driving duties. Phone in first instance to Mr. Mike Hill. Film Camera Assistant (ST1/2) Jim Marshall (Products) Limited, Denbigh Road, Bletchley, Milton Keynes MK1 1DQ. Slary Range £5,568-£8,451 plus £1347 London Weighting Allowance. Telephone: Milton Keynes (0908) 75411. (2788) The Centre's Broadcast quality colour programmes use 16mm sound film and video insert provided by the film camera section in which this vacancy has arisen. Applicants should have relevant training and experience in servicing the requirements of film and video cameras together with the associated location THE UNIVERSITY OF LEEDS lighting equipment, in television or documentary film environment. TECHNICIAN Electrical & Electronic Engineering PRODUCTION DIVISION Required in the electronics workshop. The workshop staff are responsible for the maintenance of electronic instruments and Television Maintenance Engineer for the development and construction of electronic equipment for both teaching and research. Applicants should have an (ST1 /2) [Re-advertised9 appropriate qualification (minimum ONC or equivalent) and Salary Range £7470-£8451 + £1347 London Weighting in preferably Plus allowance considerable experience electronic engineering, Allowance. £192 shift including computers. A maintenance engineer is required to work at the Television and Production Centre which is equipped to professional colour TV broadcasting standards. Salary will be grade 5 £6,581-£7,684 p.a. The engineer will work in a section of four which is responsible for maintaining Applications to Mr. W.G. Black, a high level of performance of a wide range of sound and vision equipmen. Department of Electrical & Electronic Engineering, The University of Leeds, Leeds LS2 9JT. (2779) Full job description and application forms for all the above posts are available from EO/ Estab 1B, Room 366, The County Hall, London SE 1 7PB. Please S.A.E. The closing date for completed application forms is the 2nd J ry 1985 These post are suitable for Job -share. (2769) ILEA is an Equal Opportunities Employer

Philips Drake Electronics is an expanding company specialising specialising in the design and manufacture of equipment for the Broadcasting Industry. We now require engineers for the following positions: PROJECT ENGINEER A vacancy exists in our Projects department for an YOU'VE BUILT MICROPROCESSOR enthusiastic and self motivated engineer. The department deals primarily with the system design of broadcast communications PRODUCTS:- equipment to customers' requirements and is responsible for the CONTROLLED preparation of production and handbook documentation in addition to providing technical support for our sales, NOW HAVE HAND IN manufacturing and test department. A suitable engineering qualification together with some DESIGNING THEM experience in broadcast or the professional audio industry is essential. FOR YOUNG, OPPORTUNITIES ANALOGUE DESIGN ENGINEER QUALIFIED ENGINEERS We are looking for an experienced engineer to join our development team. The successful candidate will be involved in mini to £11,000 pa South Herts High performance computers all aspects of design from concept to production. He/She will Cambs Custom-made CAD systems c£7,500 most likely have a relevant degree and must be capable of producing innovative but practical designs with minimum Suffolk Remote TV, video and air supervision. Experience of the professional audio industry would reconnaisance systems c £9,000 be an advantage. Essex Remote controlled TEST ENGINEER Broadcast communications c£7,500 We require a test engineer with experience in testing analogue c£9,000 (preferably audio) circuits and fault finding to component level. S Herts Defence and security equipment He/She will become involved in varied testing from small batch Cambs Digital guaging and read outs for produced units to complete studio communications systems and will be required to adapt to digital technology as this is c £7,000 inspection equipment introduced. Call Phil Walleron Bishop's Stortford (0279! 506464, SOFTWARE ENGINEER 9am-6pm, (out of hours answering service) A new position of microprocessor software engineer has been created and we seek a suitable candidate to design software in olorrfurther details and a confidential discussion or send your c.v. PASCAL and ASSEMBLER for the MC6800 family. The ability to to:- work on your own initiative and communicate your ideas clearly is essential. E Attractive salaries will be offered to the right people. alai If any of the above positions appeal to you please apply in writing including your current Recruitment CV or phone Jill Humphreys on Welwyn Garden A Dev,seon of ATA Selectee and Management Services Ltd. City (07073) 33866 for an application form. Portland House. 29 Basbow Lane.Beshop's Storttord, fleets Philip Drake Electronics Ltd., London. Lc.d..M.ncn.st.r.Binningb.in. Edinburg. Brltd. Bracknell. Bishop's (2789) 37 Broadwater Road, Storeord. Crawly. Milton Key... Welwyn Garden City, Herts All 2AX. (2782)

98 ELECTRONICS & W0'IRELESS WORLD DECEMBER 1984

www.americanradiohistory.com Electronic Engineers HAMPSTEAD HEALTH - AUTHORITY ROYAL FREE HOSPTIAL Whatyou want, where you wan!! DEPARTMENT OF MEDICAL PHYSICS TJB Electrotechnical Personnel Services is a specialised appointments Salary - £5171 - £6798 plus £1042 service for electrical and electronic engineers. We have clients throughout London Weighting Allowance Electronics technician (Medical the UK who urgently need technical staff at all levels from Junior Technician Physics Technician IV) required to join small team responsible for to Senior Management. Vacancies exist in all branches of electronics and servicing, maintenance and electronic development of allied disciplines - right through from design to marketing - at salary radiotherapy units. Principal units levels from around are a linear accelerator, two cobalt £5000-£15000. units (one performing three- dimensional treatments) and a If you wish to make the most of your qualifications and experience and treatment simulator. Training will be move given in the specialist techniques another rung Or two up the ladder we will be pleased to help you. required; study for further All qualifications is encourged. The applications are treated in strict confidence and there is no danger of post gives an opportunity for gaining your present familiarity with a wide range of employer (or other companies you specify) being made aware radiotherapy and physics equipment of your application. and for participating in development projects. Qualifications - ONC, HNC, HND, final City and Guilds or equivalent, TJB ELECTROTECHNICAL Please send me a TJB or 2 'A' levels plus either 2 years as Appointments Registration form: student or junior technician or 3 PERSONNEL SERVICES, years relevant experience. 12 Mount Ephraim, Name Further details are available from Martin Welch (01) 794 0500 ext 3209 Tunbridge Wells, Job description and application form Kent. TN4 8AS. Address available from the Personnel Department Royal Free Hospital, Pond Street, Hampstead, London Tel: 0892 39388 NW3 2QG (861) Please quote reference no: 1499 (24 Hour Answering Service) (2781)

TECHNICAL PROJECTS LIMITED is a young and rapidly growing company specialising in the development, manufacture and marketing of audio products for the professional enter- tainments industry worldwide. Our customers include the BBC, inde- VDU pendent television companies, local radio, hire and production houses, manufacturers, education and MOD etc. We are noted for product quality and customer service. Due to expanding business opportunities the fol- ANALOGUE lowing two vacancies have arisen: FIELD SALES ENGINEERS (Audio/Acoustic Measuring Equipment) DESIGN 1. Wales, Midlands & East Anglia 2. Northern England and Scotland To £16k Thames Valley Applications are invited from sales engineers ideally in the field of profes- Our client, an international name at the forefront of sional audio/acoustic measurement and its related test products, possi- bly working in a large company and wishing to make an impact in a computer peripheral technology, is seeking an ex- smaller one using their expertise and experience in field sales to promote the perienced Analogue Electronics Engineer to join its company's growth. expanding VDU manufacturing division. A combined five figure salary and commission of circa £19.000 is envi- This represents an ideal opportunity to become part of a saged in the first year with every opportunity for increase and advance- team pioneering the development of VDU's and in- ment into management. Company car provided plus normal benefits. telligent terminals. Candidates will therefore need to be Please write or telephone: The Sales Manager, TECHNICAL PROJECTS LIMITED Unit 2, able to demonstrate strong innovative flair backed by Whites solid experience in the design of VDU's or TV drive Samuel Ind. Estate, Medina Road, Cowes, Isle of Wight, P031 7LP Telephone: (0983) 291553 (2755) circuits and PSU's. An appropriate qualification, pre- ferably a degree, is essential. The rewards are high, including a full range of big company benefits, assistance with relocation and very real prospects for career development within a young and extremely successful company. SWISS COMPANY Please C.V. write, enclosing a full and quoting FOR EXPERIENCED ENGINEER FOR reference number WW/824 to The Chief Executive, LOOKS DCM Appointments, 66 Frith Street, London WI. INSTALLATION AND SERVICE OF - SSB TRANSCEIVERS 1.6 - 30 MHZ FREQUENCY SYNTHESIZED - IN ADDITION 1 KW POWER AMPLIFIERS DCM INTERESTING POSITION WITH SOME TRAVELLING Mr. K. Minder APPOINTMENTS 11G BICORD AG. CH 6331 Huenenberg Zug Switzerland. (2792) (2712)

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 99

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HIGHLAND HEALTH BOARD Department of Medical Physics and Bio -Engineering, Raigmore JOINT Hospital, Inverness SENIOR EUROPEAN TECHNICIAN/ TECHNICIAN - TORUS Electronics Section A vacancy exists for a Senior Technician/Technician with ONC or high qualifications. The work involves design, construction, repair Radio Frequency/ and maintenance, as well as clinical involvement. Salary is - Grade Ill £6408-£8283 Grade IV £5404-£7104 Electronic Technician Job description and application form from Area Personnel Officer, Highland Health Board, 17 Old ... to join JET, an exciting multi -national scientific and technical project. JET is the Edinburgh Road, Inverness. largest single project in the European fusion research programme, investigating (Tel. 0463 239851) the feasibility of nuclear fusion as a new energy source. For additional information contact Mr A R Bowley, Deputy The project is sited in the attractive countryside of the Thames Valley at Culham Director. Laboratory near Oxford. The modern, purpose built laboratory complex is equip- (Tel. 0463 234151 ext 276 or 277) ped with large and advanced research facilities supplied by European industry, (2786) and offers excellent opportunities to acquire valuable experience in many challenging areas of technological research. We now seek a Radio Frequency/Electronic Technician to join our team of over HI -TECH SERVICING 500 staff currently working on the project. He or she will play an important part in An opportunity exists in a small but lively distribution and support the expanding scientific programme which will be carried out during the project company based in central operation phase up to the 1990's. London. We specialise in professional audio products for The successful applicant will be involved in the procurement, installation, oper- the broadcast TV and commercial ation, maintenance and modification of high power radio frequency amplifiers, recording industries - many microprocessor based. transmission line equipment and associated control circuitry. Applicants should be able to fault is re- find down to component level and A degree in electrical/electronic engineering or an equivalent qualification must have 3 years experience in quired and several years' relevant experience of RF equipment in broadcast, in- analogue and digital circuitry. dustrial and scientific use, would be an advantage. An HND, HNC or C&G qualification would be an The successful candidate will be offered an appointment within the UKAEA and advantage as would a clean driving licence. will then be assigned to JET. Contact: Brandon McHale or Salary will be dependent on qualifications, age and experience, in the range Nicholas Martin on £7,990 - £13,665. 01-387 1262 (2775) Excellent working conditions, including restaurant and social facilities, are pro- vided and other benefits include: Generous holidays and sick leave allowances ELECTRONIC Transport from 'many local towns and villages Housing or housing assistance in appropriate cases TECHNICIAN Children of staff assigned to the project are entitled to attend the nearby Euro- Stage Lighting Control pean school Manufacturing Company Tuition in European languages is available to staff assigned to JET. require bright Technician for testing/servicing desks and For an application form and further details please write to Mr. M. Taylor, The Per- dimmer systems. An/Dig sonnel Department, UKAEA, Culham Laboratory, Abingdon, Oxon OX14 3DB, experience necessary; mic- quoting reference J3225. Closing date for applications is two weeks from the roprocessor experience an publication of the advertisement. (2787) advantage; formal qualifica- tion not essential. Contact Richard Nother 01-965 8522 rt. _ _ _ tttttt. 1 ij CAPITAL APPOINTMENTS LTD THE UK's No. 1 ELECTRONICS AGENCY If an advertisement 1 ;; Ir If you have HNC/TEC or higher qualifications and are looking for a job in design, test, customer service, technical is wrong we're here sales or similar fields: 1 Telephone now for our free jobs list o We have vacancies In all areas of the UK to put it right. 1 Salarles to £15,000 pa 1 01 808 3050 If you see an advertisement in the press, in print, 1 (24hours) on posters or in the cinema which you find I unacceptable, write to us at the address below. CAPITAL APPOINTMENTS LTD 76 WILLOUGHBY LANE, LONDON Nil OSF The Advertising Standards Authority. 1 291j IL. ASA Ltd, Dept 3 Brook House, Torrington Place, London WC 1E 7HN

1110 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

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ARTICLES FOR SALE Advanced Portable Battery or Mains Oscilloscope . SE Laboratories 111 Oscilloscope - Solid State - General purpose - Bandwidth OC to 18/20MC/S at 20MV/CM - telecommunications: Dual Channel - Rise time 19NS - Calibrated Sweep - Calibrator - Display careers with extensive scope at Cheltenham 10CMS.8CMS - Power AC - 95 Volts to 100-190 Volts to 260 or 24 Voit DC bat- tery -Size W.25.5.CM- H25.5CCMS- 56CMS Deep - WT 11 4KGS-Car- Join the Government Communications Headquarters, rying handle - Tested in fan condition with operating instructions £120.00. Static Power Supply Standby Unit. Made by Saunders Electronics. Contains one of the world's foremost centres for R & D and produc- Automatic Changeover Switch in the event of mains supply failure. Also auto- tion in voice/data communications ranging from HF to matic Battery charger for 24 volt battery supply Output 240AC 50c/s Sine -Wave satellite and their security. Some of GCHQ's facilities at 150 to 200 watts. Input supply or battery 24 or 28 volts DC. Output short cocu- - uiI protected. Size -W 38.3cros - 23.5cros. - 0 19 7cros - WT 21 KGS. are unique and there is substantial emphasis on creative Housed in a grey metal cabinet with lockable front. Supplied in liar condition solutions for solving complex communications problems £100.00 or new and boxed £150.00 with book. Marconi Circuit Magnification Melee TF1245 - £150.00. TF1245A- £200. using state-of-the-art techniques including computer/ Latest Bulk Government Release - Cossor Oscilloscope COU 150 (C5531/3) £ 150 only. Solid state general purpose band- microprocessor applications. Current opportunities are width DC to 35MHz at 5 MV/CM - Dual Channel- High brightness display (8.10cm) Full delayed time base with gated mode - Risetlme IONS- Illuminated graticole - Beam tinder - Calibrator 1KHz squarewave -Power 100 - 120V. 200V - 250 for: volts AC - Sloe W 26CM -H 26CM -11 CM deep - WT 12.5 11 G. carrying handle - colour blue - protection cover front containing polarized viewer and camera adaptor plate - probe (1) - Mains lead. Tested in Fair condition with operating instructions - £150.00. Electron Microscope. Made by Jeol Type J EM - 200A - Resolving power: 3.4A (Lattice or 5A (Lattice) °, 5 A(pointto point) Accelerating voltage 50,100. 150, 200KV. Magnification X 1000 - 200,000. Surplus from well known government depart- Telecommunication ment. Test reports up to 1983. Supplied complete with all books and manual, spare parts and tool kits 06500.00. (probably a once in a Iilelime chance of obtaining this instrument at this price). Communication Receivers. Racal 500KC/S to 30MC/S in 30 hands 1 MC/SWIOE - Roll MK l t f 125. RA 17L 0150. RAii 7E Technical Officers 0200. New Metal Louvred Cases for above 025. All receivers are air tested and calibrated in our workshop -supplied with dustcover - operation instructions - circuit - in lair used condition. Racal Synthesisers (Decade frequency generators) Two levels of entry providing two salary scales: MA350B Solid State for use with - MA79 - RA217 - RA1218 Etc 0100 to £150. MA250 - 1.6MC/S to 31.6 MC/S 0100. MA1350 for use with RA17 scelver C100. MA259G Precision frequency standard 5MC/S - 1MC/S - IOOKHz 010010 0150. £6262-£8580 & £8420-£9522 Panoramic Adaptor RA66 £150. RÁ137 and RA37£4Stn 075 LF convertors l0to 980KC/S. RA218 Independent S88 unit 050 Minimum qualifications are TEC/SCOTEC in Electronics/ RA98 SSB-ISM Covertor 050. RA 121 550-ISB convertor 075. EC964/7K Solid state - single channel -S88- mains or bat- tery -1.0 to 27.5 MC/S and 40010 535KHZ 0100 with manual Plessey PR 155G S01id Slate 60KCIS 30MC/S Creed Telecommunications or a similar discipline or C & G Part - 0400. 75 Teleprinters - Fitted tape punch and gearbox for 50 and 75 bauds - 110voits AC supply - in original transport tray Il Telecommunications Technicians Certificate or Part I sealed in polythene - like new 015EA. Redilon ITü Audio Teleprinter convertor receiver solid state - supply 110 or 240AC plus Maths B, Telecommunication Principles B and either - Made for use with above teleprinter enabling print-out of messages received from audio input of communication receiver 015 with circuit tested. Redd on TT10 Convertor as above but includes transmit facilities 020. Oscilloscopes - stocks Radio Line Transmission B or Computers B or equivalent: always changing Tektronix 465 - 1OOMC/S £750 FM Recorder Sanghmd Sabre 111 14 channels £350 Transtel Matrix ONC in Electrical, Electronics or Telecommunications En- printers -AF11R -5 level Baudot Code - up to 300 Bauds - for print out on plain teleprinter paper £50 to £ 100. Transtel AHI1 R - As above but also 8 level ASCII (CCITT No 2 and CCITT No.5) Like new £ 100. Army field telephone sets, Type T - gineering or a CIE Part I Pass, or formal approved Service L and J - Large quantity in stock £6 to £15 depending on type and quantity P.O.R. Don 10 Telephone Cable - hall mile technical training. Additionally, at least four years' (lower canvas containers £20. Night veiwleg Mira -red AFV periscopes - Twin Eyepiece - 24 volt dc supply £ 100ea. Original cost to government over £ t 1,000ea Static inverlors -12 or 24 von input - 240 volt DC supply £ 100ea. Original cost to govern- level) or seven years' (higher level) appropriate exper- ment over £11.000ea. Static Inverters - 12 or 24 volt input input - 240 volt AC sinewave output - various wattages ience is essential in either radio communications or radar, P.0. R. XV Mote's and pen recorders various - P .R Ferrograph series 7 ape recorders mono £100 or 240 volt mains data, input £25 to £50 Signal Generators various - TF995/A3 £60 TF801 D/8s - 10MC/S to 485MC/S £90 TF144H/A4 £90 computer or similar'electronic systems. At the lower TF1060/2 £60 HP606A - £90 £140 HP608 £50 HP612A £100 HP614A C100 HP618B £100 HP620A 0100. Marconi entry level first line technical/supervisory control of TF10640/5 L 100 TF791 Deviation meter £ 100 TF893A Power meter £50 Aerial mast assembly 30ft high complete with 1611 technicians involves "hands-on" participation and may whip aerial to mount on top - guyropes - insulators - Base and Spikes etc . in heavy duty carrying bag - new £30 Racal frequency counter Type 836 £50 Tektronix plugs-ins - 1Ai £50. 1A2 £40. 1A4 £100 M£50. All items are bought involve individual work of a highly technical nature. The directlrom H. M Government being surplus equipment Price is Ex works. SAE for enquiries Phone' or appointment for higher level involves application of technical knowledge demonstration of any items. Also availability or price change. V A T. and carriage extra

and experience to work planning including implementa- EXPORT TRADE AND QUANTITY DISCOUNTS GIVEN tion of medium to large scale projects. JOHNS RADIO 10274) 684007 WHITEHALL WORKS. 84 WHITEHALL ROAD EAST BIRENSHAW. BRADFORD 813112E

WANTED REDUNDANT TEST EQUIPMENT - RECEIVING AND TRANSMITTING EQUIPMENT - VALVES - PLUGS - Radio Technicians - SOCKETSSYNCHROSETC (2734) £5485-£7818

To provide all aspects of technical support. Promotion HEWLETT PACKARD. Spectrum Analyzer prospects are good and linked with active encouragement 141B/ 8553L/8552A 1kH2 110MHz B.W. 54)Hz LIST OF SURPLUS ICs. - to acquire further skills and experience. Minimum qualifi- - 300KHz in 9 Ranges. Scan Width 2Khz - 100MHz in 15 ranges £3,200 Oscilloscope type cations a TEC in SN74LS 240N 220 4 £1.18 ea. are Certificate Telecommunications or 1712A 200MHz B.W. Dual Trace, Dual Delayed SN74LS 08N 220 © ea. equivalent plus two or more years' practical experience. £ .28 T.B. Solid State (small) £1200 Power Meter SN74LS 368AN 220 (e £ .49 ea. Cheltenham, a handsome Regency town, is finely en- P.R.D. 6685 Thermo - Electric Thin Film Sensor 3uW 30mW 9 ranges, 10mHz 12.4Ghz £200 dowed with cultural, sports and other facilities which are SN74LS 138N 879 £ .50 ea. - 74LS273PC l'hone V.H.F. Engineering 01-428 0974 (2773) equally available in nearby Gloucester. Close to some of 220 £1.34 ea. TC5501P Britain's most magnificent countryside, the area also VIDEO/TV Test Equipment (PAL) Philips offers reasonably priced housing. Relocation assistance (Toshiba) 176 4 £1.83 ea. PM5519 pattern generator£480. Digìtel 1)4060-01 M5L5101 LP -1 noise meter £480 (VAT) extra may be available. Contact: Hi -Test, 64 (mitsubishi) 270 ea. Castellian Road, London W9 4 £1.83 1EX. Tel: (01) 289-3533 (2772) UPB 8212C (Nec) 220 ü £1.55 ea. For further information and your application form, please CD 40106 BCN 120 114 £ .50 ea. telephone Cheltenham (0242132912/3 or write to: ENCAPSULATING EQUIPMENT FOR.coils, HEF40106 BP 100 4 £ .50 ea. transformers, components, degassing silicon D8085AC 59 4 £2.78 ea. rubber, resin, epoxy. Lost wax casting for brass, MSM5832RS 220 © £3.00 ea. bronze, silver, etc. Impregnating coils, transfor- mers, components. Vacuum equipment, low cost, M58725P 210 ® £3.06 ea. used and new. Also for CRT regunrnng metallis- ing. Research & Development. Barratts, Mayo Recruitment Office, Government Communications Headquarters, Road, Croydon CRO 2QP. 01-684 9917. (9678) Oakley, Priors Road, Cheltenham, PRECISION LORDS LTD. BBC MICRO active filter design program high- Gloucestershire, GL52 5AJ. 12452) Craven House, pass, lowpass, bandpass, bandstop, Butterworth/ Carleton New Road., Chebyshev to eight order. Includes printer screen dump. S.A.E. for details. Cassette £7.00, 40/80 Skipton. BD23 2DE Track Disk £9.50. R. Harrison 20. Wingrove Hill River Dover Kent CT17 ONN (2766) SIGNAL RADIO North Yorkshire Require a Tel: Skipton (0756) 69475 THE BEST Electronic Component Audio and Video Accessory shop in East Kent. More than (2780) BROADCAST ENGINEER CHALLENGING £70,000 turnover and rising with 334, profit. Two For general duties in the Engineering joining freehold lock -up shops plus stores esta- Department. The successful POST blished 10 years, 5 day week unopposed trade freeholds, goodwill and stock with fixtures and fit- applicant will have a HND/Degree tings £52,000 every assistance given to purcha- qualification or equivalent training in a Dynamic radio service engineer ser. Phone Thanet 594072 Business Hours, not Hewlett Packard Equipment including No. relevant subject. Nigeria Thursday or Sunday. (P770) required for 3702BIFF Receiver, No. 3705A Diff. Phase Experience in broadcasting and a For HF SSB and VHF/UHF Synthesised Detector, No. HP37101FBB Transmitter, clean driving licence desirable. equipment No. 3716ABB Transmitter, No. 6518 Test Salary: Negotiable depending on PCB HAND ASSEMBLY -any quantity. The position is well rewarded. Oscillator. Highest quality at sensible prices. INTER- experience. Contact Aplab Oscilloscope 3030, Ratel Regulated ESTED? Phone 01-274 3070 (2570) Apply with full C.V. to: D.C. Power Supply, Bird Thruline 43

Dave Donahue, 01 444 7207 Wattme,er, two Ra'r I H.P.C. NetzgeraV Chief Engineer, Power .'Jupply. VALVES, PROJECTOR Lamps, 6000 types, list 75p, world wide export. Cox radio (Sus .ex) Ltd., Studio 257, (2764 ) Further details - Henry Butcher & Co. Stoke Rd., Stoke-on-Trent. 79/83 Colmore Row, Birmingham B3 2AP The Parade, East Wittering, Sussex. Phone (0243) 672023 (1991) ST4 2SR (2680) - 021-236-5736. Ref: TH (2791)

ELECTRONICS & WIRELESS WORLD DECEMBER 1984 101

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ARTICLES FOR SALE WANTED

TO MANUFACTURERS, WHOLESALERS VERBGATE LTD. BULK BUYERS. ETC. We buy large and small par- WANTED cels of surplus I/C, transistors, LARGE QUANTITIES OF RADIO, TV AND capacitors and related Test equipment, receivers, ELECTRONIC COMPONENTS FOR DISPOSAI, electronic stock. Immediate valves, transmitters, com- SEMICONDUCTORS, all types, INTEGRATED CIRCUITS, TRANSISTORS, settlement ponents, cable and DIODES, RECTIFIERS, THYRISTORS, etc. RESISTORS, C/F, M/F, W/W, etc. Tel: 01-208 0766 electronic scrap and quan- CAPACITORS, SILVER MICA, POLYSTYRENE, C280, C296, DISC CERA- Telex: 8814998 tity. Prompt service and MICS, PLATE CERAMICS, etc. 12478) cash. Member of A.R.R.A. ELECTROLYTIC CONDENSERS, SPEAKERS, CONNECTING WIRE, CABLES, SCREENED WIRE, SCREWS, NUTS, CHOKES, TRANSFOR- MERS, etc. STEWART OF READING M&BRADIO AT KNOCKOUT PRICES - Come and pay us a visit ALADDIN'S CAVE 86 Bishopsgate Street ALL 110 WYKEHAM ROAD Leeds LS1 4BB TELEPHONE: 445 0749/445 2713 READING RG61PL 0532 435649 R.HENSON LTD. TEL NO: 073468041 21 Lodge Lane, North Finchley, London, N.12 1995ti (5 minutes from Tally Ho Corner) (1613) TOP PRICES PAID FOR ALL TYPES OF SURPLUS TEST EQUIPMENT, DRAMS (4164 15ONS) FUJ TYPE MB8264-15 PACKS OF 8 C32.50. COMPUTER EQUIPMENT, DRAM 4027-3 PACK OF 8 C16.00 COMPONENTS etc. WANTED STATIC RAM 2102 PACK OF 8 £8.00 ANY QUANTITY. (26161 8080A CHIPSET CaO 1 x8224, 15(8238, 1 x82550. SURPLUS ELECTRONIC

OPTOELECTRONICS 1 1x8253. 2x8259A, x8251 A. LOT FOR C35. COMPONENTS AND DATA BOOK 1984 25 PIN D FEMALE IDC CONNECTOR C/W FLAT CABLE £4.00 9 PIN D MALE IDC CONNECTOR EQUIPMENT SINGLE ENDED M OR F Price by Texas £6.00 C2.00 RS 232 LEADS [4.00 DUAL ENDED MF/MM/FF £7.50 SURPLUS We also welcome the opportunity to quote for NOTE, ALL ITEMS LIMITED STOCK. SPEC. PLS We offer good prices for test equipment, complete factory clearance DIGITAL ELECTRONIC CIRCUITS POP NO VAT C. W.O. top quality ADD 50p components, redundant computers, B. BAMBER ELECTRONICS & SYSTEMS by N.M. Morris industrial grade componenets settle- PCB's connectors. Immediate 5 STATION ROAD, LITTLEPORT, CAMBS. PRICE: £5.45 CAMTRONICS, 28 Perowne St., ment. Cambridge Phone: Ely (0353)860185 MICROELECTRONICS: Tel Cambridge 68990 (2771) TIMEBASE 124831 A PRACTICAL INTRODUCTION by 94 Alfriston Gardens R A. Sparkes PRICE: £8.50 Sholling, Southampton SO2 8FU MORSE READING PROGS.Work on clean sig- Telephone: (0703)431323 CAPACITY AVAILABLE SOLDERING IN ELECTRONICS by ZX81 1K UNEX- nals without hardware interface. (18321 R.J. Klein Wassin Wassink PRICE: £51.00 PANDED MEMORY. Translated code with word and line spaces for easy reading Automatic scroll OPTICAL FIBER COMMUNICATIONS action. £7 incl. (2532) BY G. Keiser PRICE: £9.50 TW ELECTRONICS LTD WAVEGUIDE, Flanges and dishes. All standard THE PCB ASSEMBLERS DIGITAL IMAGE ANALYSIS sizes and alloys (new material only) from stock. The Publishers take all by S. Levlaldi PRICE: £26.00 Special sizes to order. Earth Stations, 01-228 reasonable care to ensure that More and more companies are investi- 7876. 22 Howie Street, London S W 11 4AR. (2099) gating the advantages of using a profes- SEMI -CUSTOM IC DESIGN & VLSI classified advertisements are sional subcontractor. Such an undertak- PJ Hicks PRICE. ing requires certain assurances. by £13.50 BRIDGES waveform/transistor analysers. Cali- genuine, but readers must satisfy Millivoltmeters. Dynamome- of them MOS LSI brators, Standards. themselves that they will be TW are able to satisfy all - INTRODUCTION TO ters. KW meters. Oscilloscopes. Recorders. Sig- quality, competitive pricing, firm delivey DESIGN by J. Mayor PRICE: £18.50 obtaining what they require nal generators - sweep, low distortion, true and close co-operation with the cus- RMS, audio, FM, deviation. Tel. 040 before entering into transactions, tomer. HANDBOOK OF BATTERIES & 376236. (1627) particularly if they involve large FUEL CELLS by D Linden PRICE £63.00 Assembled boards at 100% inspected sums of money. 2519) before flow soldering and reinspected THE DESIGN & DRAFTING OF after automatic cropping and cleaning. PRINTED CIRCUITS by D. Lindsey Every batch of boards is is- Ignition Test Adaptor for oscilloscope completed PRICE £41 50 with a signed certificate of confor- £39.20 MHz battery/mains oscilloscope CAPACITY AVAILABLE sued mity and quality - our final assurance. ALL PRICES INCLUDE £175. 40 piece socket tool set £6.75. Woa- * tan U.V. lamps £7.50. Self tapping screws. For further details, contact us at our new POSTAGE * Neon Strobe lamps £1.500a. MIG Welder works: with continuous and spot weld - chassis & Blenheim Industrial Perk case manufacture £350. Crypton Bury St. Edmunds THE MODERN Tachometer £25. TR cells TRP8 £10ea, Suffolk IP33 3UT Fibreoptic light source for microscope, endoscope etc., £35. Large compressor Telephone: 0284 3931 (1466) BOOK CO. £175. Air drill £15. Ferrograph continuous %,0386-1332152.1 BRITAIN'S LARGEST STOCKIST loop cassettes £10. Philips FM/AM gener- ator £89. Extension philips generator for i:: B.Imtl FREE P.T.H. PROTOTYPE of the finest quality of British and American ' by same £49. Oscilloscope.Dynamco Digital with EVERY P.C.A. artwork designed us. Com- Technical Books pnamsP.C.B.Arcwork, 491Wesebourne. petitive hourly rates, and high standard of work. Voltmeter, LF amplifier, Mean Detector and Noneybourne Evesi.:,m, Worcs. 5PT. D.C., calibration system £98. BBC RP3110 iitii=llßlljiÌngzu Halstead Designs Limited, 34, High St., Halstead, 19-21 PRAED STREET cable test generator 60Kc/s-3MHz £45. Essex. Tel. (0787) 477408/474554. (2126) Sweep Generator. Oxygen Resuscitator LONDON W2 1 NP with cylinder and gas £45. Line transformer Telephone: 01-402 9176 test equipment £49. Bendix double -pulse TENDERS generator £45. Schlumberger Data logger. Closed Saturday 1 p.m. Chart recorders. Avo current shunt, Avo Please allow 14 days for 4000.v. range extender, Avo resistance reply or delivery range extension und, £10ea. Avo Wattme- ter attachment £45. etc. etc. (22451 040 376236 Aerial Mast Space (2016) to Let by Tender

1. (Kensington Heights) 036-16-458 Kensingston JAYSOFT MICRODEVELOPMENT Telephone 72m asl (ref. 38/1/2 2. Shooters Hill (Shooter Hill Water Tower) for ease of use with no comprise in technical accuracy. Designed 150m asl (ref. 687/B03 These programs are suitable for professional or amateur use. 3. Croydon (Shirley Hills Water Tower) RC LC circuits. Includes coil design Oscillator: and 163m asl (ref. 1/L) Electron 1: Class A bias Optimisation. 741 opamp LP HP and BP Active filters Logic: Software simulation of up to 30 logic gates to check design Copies of tender document may be obtained from: before the hardware stage. Can simulate fault conditions to aid fault analysis. Area Surveyor, Thames Water Authority, 20 Blyth Suitable for BBC Commodore 64 'PET'TandyM100 Road, Bromley, Kent. BR1 3UB (Ref. MAS) ('non or reduced graphics. Logic not available). New programs available every month. Disk £20.00 Tape £17.50 JAYSOFT MICRODEVELOPMENT 2, Wester Row, Greenlaw, Thames Water Berwickshire. (2794) (2729)

ELECTRONICS & WIRELESS WORLD DECEMBER 1984

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SERVICES

ELECTRONIC CIRCUIT Design and Develop- ment service. Professional engineers with many years experience in the design of analogue, digital When replying to classified ANALOG COMPUTERS LIMITED chartpak and R.F. circuitry (To 500MHz). Also PCB Design CAPACITY NOW AVAILABLE FOR: stockist and Prototype Production. Memtorport Ltd, 29, advertisements, readersare Westerings, Romsey, Hampshire. Phone Romsey 522143. (2778) recommended to take steps Design & Development, Complete Artwork Service, Camera SMALL BATCH PCBs, produced from your art- Prototype thru to Production PCB Manufacture/Assy. work. also DIALS, PANELS, LABELS. Camera to protect their interests Work, work undertaken. FAST TURNAROUND. De- tails: Winston Promotions, 9 Hatton Yle,,e, London before sending money 5 Cork Street, Eccles, Maidstone, Kent, ME20 7HG EC1N 8RU. Tel. 01405 4127/0960. (9794) (2519) TELEPHONE 106221 79987 TELEX 965633 (2348)

TURN YOUR SURPLUS i.cs transistors etc. into PTH BOARDS Fast turnround (24 hour for rush SCOPES jobs), competitive prices, full inspection, any FOR THE BEST PCB SERVICE cash, immediate settlement. We also welcome the AVAILABLE repaired and recalibrated opportunity to quote for complete factory clear- quantity considered, Kirk, Bridge Works, Cinder - All makes, all models ance. Contact COLES -HARDING & CO, 103 ford, Glos. Tel 0594 22084 (2741) Scopex, Safgan Older TEK & TO South Brink, Wisbech, Cambs. 0945 *Circuit Design & Development 584188. (9509) Digital and Analogue PROFESSIONAL DESIGN SERVICE. Ana- *Artwork layout MENDASCOPE LTD. logue/RF circuit/System design. Specialising in Otter House, DESIGN AND MANUFACTURE. ANALOGUE, PCB artwork layout and mechanical detailing. P.O. Weston Underwood microwave amplifier, oscillator and network approved standard. Olney, Bucks MK46 5JS DIGITAL, RF AND MICROWAVE CIRCUIT AND design. MOTOROLA 6805/6809 series micropro- SYSTEM DESIGN. Also PCB design, mechanical cessor design/development capability. All work *Board Manufacture BEDFORD 10234) 712445 design and prototype/small batch production. Ad- Prototype to semi-production, excellent rates. - carried out to a high standard by competent profes- 2531) enmote limited, 27 Longshot Estate, Bracknell, sional engineers. Trontech Electronic Design Ser- Berks. Tel: Bracknell (0344) 52023. (656) *Wiring & Assembly vices Ltd., Unit 8B, Rose Industrial Est., Boume PCB assembly, wiring and cable forming. Flow solder- End, Bucks. 06285 28835 (2439) ing facilities available. VALVE Quad, Leak, Garrard, Radford, HI-FI, *Test Lowther, Thorens etc., All types of valve equip- Full test facilities available. ment considered for purchase. The Vintage Wire- IMPROVE YOUR PROSPECTS DESIGN AND DEVELOPMENT SERVICE. RF less Co., Tudor House, Cossham Street, Man- transmitters and receivers. Telemetery U.H.F. One or all services available. gotsfield, Bristol BS17 3EN. Tel: 0272-565472, with skills that employers want - learn V. H.F. Anologue and digital circuits, control sys- Please telephone Chelmsford or Telex 437287 Sharet G. (2671) tems. Full manufacturing (02451 357935, or write to HCR the easy way with modem home study facilities. RCS Electron- Electronics, The Industrial Unit,' courses from Ideal Schools. ics. Wolsey Road, Ashford, Middx. Phone Dr. Eric Parker Road, Chelmsford. Falkner on 53661. (2637) (30mins from Liverpool Street St.) (1169) WANTED MODERN ELECTRONICS Train for success in the fastest ever growing industrial sector. CIRCOLEC COMPUTER PROGRAMMING THE COMPLETE ELECTRONIC SERVICE VLF The demand for Programmers is increasing constantly - don't miss out! Artwork, Circuit Design, PCB Assembly, Test & Repair Service, Q.A. Metal -Detector For free booklet write today to Consultancy, Prototypes, Final Assembly. Full PCB Flow Soldering Service. Circuit diagram IDEAL SCHOOLS Quality workmanship by professionals at economic prices. (Ref. EW2) Please telephone 01-646 5686 for advice or further details. required 60 St. Enoch Sq TAMWORTH MANOR ¡7DE4L° Glasgow G1 UK. e BOX No. 2790 Tel: 041-248 5200 302-310 COMMONSIDE EAST, MITCHAM 11391) (2774)

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www.americanradiohistory.com Add 8 channels to your 'scope New Thurlby 0M358 multiplexer £169+vat /trr'/r'rWartt'f//r'r`, The Thurlby 0M358 gives any oscilloscope an 8 channel display. Observing many waveforms simultaneously can be essential when analysing sophisti- cated equipment. Application areas include microprocessor based products, data transmission systems, A to D converters, frequency synthesizers etc. The 0M358 is ideal for digital equipment (it can often solve problems that would otherwise need a fast logic analyser) but, unlike dedicated logic test e e e Ckt Ck? (3,13 Cana instruments, it is equally suited to analogue waveforms. t4s .,.º.,...... The OM358 has a bandwidth of 35MHz and 3% calibration accuracy. Each sm.x13.11111. input has an impedance of 1M2 - 20pF and accepts signals up to ± 6V. An 8 e channel, 4 channel, or single channel display can be selected with triggering CNS I:tiré Ct17 CMa from any channel. Colour data sheet with full specifications available. Thurlby Electronics Ltd 0M358 with two BNC III Thurlby /H Z New Road, St.Ives, Cambs. cables £197.80 designed and built .n Britain PE17 4BG Tel: (0480) 63570 (inc P & P and VAT) CIRCLE 73 FOR FURTHER DETAILS.

INDEX TO Nhreléssó$rld ADVERTISERS Appointments Vacant Advertisements appear on pages 95-103

PAGE PAGE PAGE Airlink Transformers 36 Electrovalue 91 M+B Radio (Leeds) 30 Andelos systems 10 83 Ellmax Electronics 42 Micro Concept 16 AM Electronics 42 EMS Manufacturing Ltd 39 Aymon Products Ltd 27 Electronics Wireless World Editorial Number One Systems 62 Aspen Electronics 62 feature List 16 " Pantechnic 16 PM Components 48/49 B. Bamber Electronics 63 Farrell Instruments Inside front cover Barrie Electronics Ltd 62 Field Electric Ltd 1 Radford Electronics 88 Beckenham Peripherals 94 Radiocode Clocks Ltd 39 Black Star Ltd 42 Gemini Micro Computers 10/11 Radio Component Specialities 50 Global Specialies Corporation 9 Radio Society of Great Britain 68 88 C & A Electronics GNC Design 36 Ralph Electronics 83 68 Cambridge Kits G.P. Industrial Electronics 47 Reticon EG&G 36 Cambridge Micro processor 67 Grandata 30 Cirkit Holdings PLC 4/5 Greatech Instruments Inside back cover Sherwood Data systems 1 Colomor Electronics 35 Skywave Software 35 Combe Martin Electronics 27 Happy Memories 87 South Midland Communications 91 Conguin Software 83 Harris Electronics London 42 Sowter Ltd EA 12 Crotech Instruments 88 Harrison Bros 50 Special Products Distribution 10 Crimson Elektrik Stroke 84 Henrys/Audio Electronics 28/29 Stewart of Reading 84 Cybernetic Applications 39 Henson Ltd (R) 27 Surrey Electronic Ltd 50 Hi -Tech Components (Midwich) 58/59 Dataman Designs Outside back cover H Square Electronics 62 Techtest Ltd 12 Datuir 88 Technomatic Ltd 40/41 Dewsbury Electronics 91 JDR Sheetmetal 50 Thacker & Son LTd (AM) 10 Digitask 94 Thandar Electronics Ltd 35 Display Electronics 92/93 ILP Electronics 27 Thanet ElectronicsLtd 68 Integrex Ltd 12 Thurlby Electronics Ltd 94 104 Easibind 94 TK Electronics 62 Edicron Ltd 87 Langrex Supplies 13 Triangle Digital Services 83 Electronics Brokers 14/15 LJ Electronics Ltd 30 Electronic Equipment Co 84 Lyons Instruments Ltd 87 Valradio Power Ltd 1

OVERSEAS ADVERTISEMENT AGENTS Japan: Mr Inatsuki, Trade Media - IBPA (Japan), B.212. Azabu Jack Mantel, The Farley Co., Suite 650, Ranna Building, France & Belgium: Norbert Hellin, 50 Rue de Chemin Veal, F- Heights, 1.5.10 Roppongi, Minato-ku 106. Cleveland, Ohio 4415 - Telephone (216) 621 1919. 9100, Boulogne, Paris. Telephone: (03) 585 0581. Ray Rickles, Ray Rickles & Co., P.O. Box 2028, Miami Beach, Florida 33140 - Telephone (305) 532 7301. Hungary: Ms Edit, Bajusz, Hungexpo Advertising Agency, United States of America: Jay Feinnan, Business Press Tim Parks, Ray Rickles & Co., 3116 Maple Drive N.E., Atlanta, Budapest XIV, Varosliget. International Ltd, 205 East 42nd Street, New York, NY 10017 - Georgia 30305. Telephone (404) 237 7432. Telephone: 225 008 - Telex: Budapest 22-4525 Telephone (212) 867-2080 - Telex: 23827. Mike Loughlin Business Press International, 15055, memorial INTFOIRE Jack Farley Jnr., The Farley Coi. Suite 1584, 35 East Walker Ste 119, Houston, Texas - Telephone (713) 783 8673. Drive, Chicago, Illonois 60601 - Telephone (312) 63074. Canada: Colin H. MacCulloch, International Advertising Italy: Sig C. Epis, Etas -Kompass, S.p.a. - Servizio Estero, Via Victor A. Jauch, Elmatex International, P.O. Box 34607, Los Consultants Ltd., 915 Carlton Tower, 2 Carlton Street, Toronto 2 Mantegna 6, 20154 Milan. Angeles, Calif. 90034, USA - Telephone (213) 821-8581 - - Telephone (416) 364 2269. Telephone: 347051 - Telex: 37342 Kompass. Telex: 18-1059. 'Also subscription agents.

Printed in Great Britain by Index Printers Ltd., Oldhill, Dunstable, and typeset by Legendary Characters, South Street, Lancing, for the proprietors, Business Press International, Quadrant House, The Quadrant, Sutton, Surrey SM2 SAS. O Business Press International 1984. Wireless World can be obtained abroad from the following: AUSTRALIA and NEW ZEALAND: Gordon & Gotch Ltd. INDIA: A. H. Wheeler & Co. CANADA: The Wm. Dawson Subscription Service Ltd., Gordon & Gotch Ltd. SOUTH AFRICA: Central News Agency Ltd: Willian Dawson & Sons (S.A.) Ltd. UNITED STATES: Eastern News Distribution Inc., 14th Floor, Ill Eighth Avenue, New York, N.Y. 10111.

104 ELECTRONICS & WIRELESS WORLD DECEMBER 1984

www.americanradiohistory.com Telephone: (0376) 27117 (24 -hour Ansaphone Service) 42494 LT D Telex: 987911 reatech Hay Lane, Braintree, lest ro n c s Essex CM7 6ST PRODUCTS DISTRIBUTOR FOR: DISPLAY & COMMUNICATION RICHARDSONS ELECTRONIC EUROPE LTD NEW VALVES R.F. POWER TRANSISTORS National, Varian, Mullard, RCA, ITT ... Many other types available

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SO 901429 1598 (CL64 3.90 3045 2 50 6505 3 95 5544 72.50 5008 18 BO ZSCt 006M 0 90 2502297 1100 507426 23 00 601015 17 50 5128 4450 EF40 8.50 30010005 3 00 5095 1.65 5545 96.00 8020 2SCI I I7 I SO 25C2289 12 SO 5 074210 21 00 601016.6 1300 0.2344 1.20 Eí60 2.75 360100007 49 w 6690 2.50 55510 110.00 8032 3 8 20 EF95 4.70 3CO+500A7 39 00 0956 3.95 55524 14400 8056 15.00 4664 2.80 4,650 5 SO 61420 2 75 5557 24.50 6068 1]00 E F89 2.30 01254 5 00 605 3.15 5559 51.50 8072 89 20 PRODUCTS 2.95 4.250A 7 00 6J SGT 2 95 558+ 16.85 8111 +65.00 Backward t 0 9 1 2.x5 4.4004 8 00 606 2.20 5522 36.00 61x1 90.00 Wave Oscillators MagnetronsMa Solid State Replacements EF93 1.60 400013 2 30 5480 300 5583 20.65 8122 90.00 Camera Tubes Microwave Tubes Spark Gap Tubes EF94 1.90 4.4000 6 00 OJOS 4.00 0632 22.50 8553 elm Cathode Ray Tubes Microwave Semiconductors Tetrodes EF95 3.70 4832 3 50 3.65 5636 7 00 6164 [332.00 .1113 2.75 40350 e 00 6!660 4 20 5562 8.20 8233 4.w Cold Cathode Tubes Photomultiplier Tubes Thyratrons EF194 2.00 4C92508 IEIM/ MP) 6JE6C 495 5544 17.00 8278 2900 Diodes Phototubes Transistors 6F1200 330 2.95 marcs 5651 240 e29e4 1 50 Planar Triodes E6301 90 002508 16021 J 50 6498 610 5654 2.90 83211E110 x0.00 Display Devices Transmitting Tubes EL34 3 SO 4003506 1E1011 7 00 6456 2 20 SO6s 12000 8321 0.171 68.00 Duplexers RF Amplifiers Travelling Wave Tubes 6136 2.30 4C0350Á (AMP) 6 00 64046 3.95 5670 2.75 8416 15.20 Electro -Optical Devices RF Capacitors Triodes Ella 4 95 400350F > 00 6!390 3 95 5684 28.80 8617 5.50 ELeI 1095 40015004 44 W 6660T 275 56046E 39.50 84x2 moo Gas Relays RF Resistors, Terminations Tube Socket%Accessories (163 11.50 4C0150OS 37 w 558 4.85 5696 3.30 6638 80.00 Glow Modulators RF Transistors Vacuum Capacitors ELM 2.96 402100000 78 00 6611 2.55 5718 6.20 8552 5 20 41:121 96015 Ignitrons Readout Tubes Vacuum Interrupters ELK 235 5 w 5.90 5120 1 80 8553 290.00 EL3+ 9.+0 4032 6 75 6608 200 5127 200 6606 27.50 Image Intensifiers Receiving Tubes Vacuum Relays .1360 7.95 41616OC 25 00 60E8 3.90 57.9 250 9643 66.10 Integrated 41150* 4 Circuits Rectifiers Vibrators EL500 280 50 6606 6.00 5750 1 90 8754 17 35 61503 39.00 5.500A 22 00 66048 350 5751 330 8794 233000 Klystrons Relays Vidicons ELSOS 6.00 SAR4 50 66148 5.50 6763 4.50 8874 15800 Klystron Amplifiers Silicon Controlled Rectifiers X -Ray Tubes EL519 875 5*9.4 40 6619 8.00 5796 29.40 890001 5500 E1603 9 95 68254M 2 00 61696 3 50 5914 3.00 8908 10 50 (18035 995 5022 12 00 616 METAL 1500 59224 300.00 8950 950 ALSO AVAILABLE: ELBA 995 50415004 53 00 5106 4.95 5847 12.00 9001 600 E M. 200 5022 7 .00 6198 200 58660 112 00 20 (X32 00 15 25 554 00 131.06 95 Sw7A 120.00 9950 40 w A replacement guide to dozens of Motorola Transistor part numbers. (591 200 5620708 75 5511 4.50 5688 170.00 16411 11000 Stocks of original RF Devices from such msnufscturen as: (592 330 558wc8 + 90 O 3.55 0870 40.00 ELECT90-OPTICAL 24 45 5048 O0 0010171 3.00 58105 20.00 MOTOROLA, RCA, GE, TRW, MSC, ACRIAN, TOSHIBA, FUJITSU, NEC, 6 45 50499 50 6911 3.95 587601 tow DEVICES MITSUBUSHI, PHILLIPS, AMPEREX and others (2300 95 SUM .w 804797 1.85 90 21.40 207(11 25 w ESBI 85 42990 .75 6814 7079 2.85 4819 380 307E136 21 03 EZ90 W 524GT 60 6847 3.80 5084 14 º0 207(54 25.00 F917 POWER TUBE ACCESSORIES 2 SO 64148 50 629 1.50 5694A 41.25 207E15 220.29 FO105 9 w 60J8 50 6080 2.00 55948 45.00 20PE19 2 l.w G1Ú 1 1 w 6005 70 0. 1.30 0920 sso 2ovE2o 25 CHIMNEYS CONNECTORS FINGER STOCK SOCKETS 90101 3 50 5065W 90 60605 1.95 5963 1.50 901275 23700 911.15 12 00 6406 1 95 604 2.00 5965 2.20 001276 269.00 G734 50 SOLS 1 95 6x5OT 1.85 5991 20.00 4848 25.00 ENQUIRIES: Quotation for any types not listed S.A.E. 6768 90 8131529 I BO 0080 100 6005 1.70 1262* 24.00 5777 15 OAMS 9.10 679 Z 95 6011 20,90 6708 1 95 6ANe x.º5 767 9 so 6014 ¡s¡SA _ TERMS: Cash, Postal Order of Cheque with order 6m2Z 280.00 013994 2.70 757 10.85 6014 20.00 15047 890.00 6.050 +.95 8C97 2.00 6021 3.70 2'' CREDIT: Accounts available subject to approved references 048223 5. 50 5405W 1.90 8F07 2.00 8056 10.50 ,M 148224 5.95 4.08 2.20 9574 88.00 6003 3.70 POSTAGE: Add £1.00 to order under £50 value 0401001 10.00 6055 12.90 1206 1.70 5065 7.35 010670 .9010121600 1 7815 78W91e.8.'8.228". 96.00 6054 5.50 12017 1.60 5073 3.60 VAT: All prices are 15% 518536 220.00 60579 20 12000 2.00 5080 9.20 Ultncon once on excludingVAT,please add toorderpostageand P g 493511o11on 411_8741 215 DO 6*0501 4.50 1241110 1.60 6083 72.00 GUARANTEE: All goods 04111235 66 W 6Á1360 1.80 12074 2m 6064 13,10 491 are to specification and sold with manufacturers warranty CIRCLE 3 FOR FURTHER DETAILS.

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GANG -OF -EIGHT is our FAST EPROM PROGRAMMER which handles CMOS or NMOS EPROMS from 2716 to 27256 (25XX too) using FAST or NORMAL programming methods. FAST programming 27128's takes 2 minutes, NORMAL programming takes 14. All possible levels of Vpp are covered including 25, 21 and 12.5 volts. G8 has an LCD which tells you what you're doing - or doing wrong. BLANK CHECK, VERIFY and CHECKSUM facilities are included. Good value £395 GANG -OF -EIGHT -PLUS is now available. PLUS what? Well, PLUS an RS232 INTERFACE which lets you download in INTELHEX, MOTOROLA S, TEKHEX, ASCII, SIMPLE HEX etc. Oh, yes, PLUS 50 quid too, but you might think it's worth it £445

SOFTY 2, our intelligent EPROM PROGRAMMER/EMULATOR, plugs into a TV, shows you memory and lets you TEXT -EDIT in HEX (INSERT, DELETE, SHIFT BLOCKS without overwriting or rewriting etc). It also calculates ADDRESS-OFFSETS in hex, UPLOADS and DOWNLOADS in SERIAL and PARALLEL, saves programs on TAPE, and PROGRAMS, COPIES and EMULATES EPROMS 2716, 2732 and 2532. Great DEVELOPMENT TOOL for PIGGY-BACK SINGLE -CHIPPERS and other small microsystems. TV lead, ROMULATOR-cable with 24 pin DIL Plug and power supply included, ready to plug-in and use £195 2764 and 27128 ADAPTOR lets SOFTY 2 handle larger EPROMS for £25.00 Z80 DEVELOPMENT TOOLS MENTA is a Z80 development system designed by DATAMAN for the SCHOOLS COUNCIL. MENTA has a built in ASSEMBLER and TV hex display: it lets you enter program in hex or mnemonics and execute them FULL SPEED or A STEP AT A TIME. All the REGISTERS and the STACK are displayed on -screen and you can SEE MEMORY CONTENTS CHANGING as instructions are executed. MENTA is a microsystem with 24 bits I/O - it can be used as a controller for ROBOTS and intelligent machines. MENTA appears in GCE syllabusses; a TEACHER'S GUIDE, PUPIL READER and WORKSHEETS are available - also CONTROL MODULES - UNIVERSAL I/O, A to D, D to A, MOTOR and VARIABLE SWITCHED INPUT for less than £20 each. A MENTA with TV flylead and power-supply costs £99

MICRODOCTOR is for DIAGNOSIS, finding troubles in microsystems. You just plug into the micro- processor socket, READ and WRITE to the MEMORY and I/O. MD does CHECKSUMS, RAMTESTS on memory, checks for SHORTS on the bus, and prints memory in HEX or ASCII. You can also DISASSEMBLE and print the SOURCECODE In Z80, 6502, 6800 or 8085 mnemonics. When your SCOPE or MULTIMETER can't find the problem - consult the MD. When you order say which processor or ask about multiprocessor MD £295

CONNECTIVITY I.C.T. (Intelligent Connectivity Tester) is the project name for a 40 pin dual -in -line CUSTOM -CHIP TESTERS developed by DATAMAN. The chip is called the MT7201 7 and it will appear soon in BARE -BOARD TESTERS, IDC CABLE TESTERS and LOOM ASSEMBLY EQUIPMENT all over the world. An EVALUATION-SYSTEM/CONTROLLER for ry'

LOGIC ANALYSER TA2080 by THANDAR with SPECIAL MODS by DATAMAN which gives RS232 LOGIC interface and prints TIMING and STATE diagrams - and DISASSEMBLES Z80, 6502, 6800 code on the screen or printer. ANALYSERS THANDAR TA2080 £1950 DATAMAN RETROFIT £295 CP/M with a free EPSON AND NEC COMPUTERS QX10, HX20 and PX8, PC8800. ALL COMPUTERS are sold COMPUTERS bundle of useful software written by DATAMAN. OLIVETTI TYPEWRITER INTERFACES designed by DATAMAN for ET1 21 and 221 - cheaper than a DAISYWHEEL printer RS232, HPIB (IEEE) and PARALLEL including fitting £195 OLIVETTI EPROM ERASERS from £39.00 INTERFACES

If you need more data send for a FREE LIT-PACK and an ORDER FORM or, better still, JUST BUY THE PRO- DUCT AND EXAMINE IT - you may return any item within 14 days for A FULL REFUND (we deduct only postal charges). Add £2.50 for carriage to orders below £100. ADD VAT TO ALL UK ORDERS. Terms: cheque with order. Dealers who mean business welcome. Goods normally in stock - TODAY DESPATCH IS POSSIBLE - please phone us DATAMAN DESIGNS, LOMBARD HOUSE, DORCHESTER, DORSET DT1 1. 1RX. TELEX: 418442. PHONE (0305) 68066. CIRCLE 3 FOR FURTHER INFORMATION

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