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ELECTRONICS & WIRELESS WORT.)) \1.AR('H 1

www.americanradiohistory.com Wireléss°wórld over 70 years in independent electronics publishing March 1985 Volume 91 number 1589 FEATURES

17 43 66 British invention, The new logic symbols Alarmphone innovation and by Ian Kampel by Per Andersen electronics The new standard This final part details the explained circuitry for the d.t.m.f. by R.E. Young emergency autodialler, Background to new series requiring no line 49 connection 25 GPIB Floppy discs An introduction to the bus 70 by David March accompanied by our Principles of optical equipment survey Continuing the survey of storage disc storage in microcomputers by J.R. Watkinson 31 This second article in our Sampled -data servos Aesthetic sub definitive compact disc -woofer series details the physics The second part of Dr system of the readout process Taub's new analysis - by M. Bronzite outlining the sampling Analysis of path -length and aliasing processes - diffierence leads to an is held over to the next unconventional crossover issue design REGULARS

6 72 26 Comment and News Letters Events Electro-reductionist Current dumping, challenge, World Causality, IT education telephones, CB Snafu, Neutrons probe structures 78 46 New products Literature received 37 Computer music, Low-cost modem, Image frame Communications store New-look spectrum management?, External voices, Midgley's inventions, Cable & DBS

61 Circuit ideas Vmos squelch for pulse receivers, Bit -rate generator, Z80 instruction counter, Strobe probe

www.americanradiohistory.com Front cover, designed Editor by Philip Brooker and PHILIP DARRINGTON by g.E 01-6613128 B.Sc. (Eng.), photographed by ' É.E - invention 5 F'l'MR Ae.S. Kenneth Crook, Deputy Editor British illustrates R.E. GEOFFREY SHORTER, B.Sc. innovation and Young's piece on 01-6618639 ab that Bn uP British invention, ed to show electronics ever of Technical Editor This quologstrenguias level; g which starts on as capable the global with years fields at MARTIN ECCLES over the tis W page 17. contribuuons.mbesedoing so. 01-6618638 an ,M fi.j pr.MP rtanid s yes.mo.f. rta sunce lwn^-.np°".¡ WdOl woo Projects Editor m+a, pM NEXT MONTH RICHARD LAMBLEY 01-6613039 Quartz crystals are by no means as simple as they News Editor might appear. Gordon Hulyer of Cathodeon DAVID SCOBIE explains their 01-6618632 characteristics and usage. Drawing Office Manager Current followers were ROGER GOODMAN discussed by F.J. Lidgey 01-6618690 in February 1984. He now joins forces with Technical Illustrator Christofer Toumazou to BETTY PALMER describe an accurate current follower design, Advertisement Manager which is used in a universal voltage BOB NIBBS, A.C.I.I. amplifier. 01-6613130

In "How long is a piece of MICHAEL DOWNING wire?", John Wiseman 01-6618640 looks at electrically short transmitting aerials - ASHLEY WALLIS those less than a quarter 01-6618641 wavelength - which he describes as the no -mans' Northern Sales land of design. aerial HARRY AIKEN 061-872 8861

Current issue pnce 85p, back issues (if available) £1.06, at Retail and Trade Mid: and Sales Counter, Units 1 & 2, Bankside Industrial BASEL McGOWAN Centre, Hopton Street, London SE I. Available on microfilm; please contact 021-356 4838 editor. By post, current issue £ 1.30, back issues (if available) £1.40, order and payments to Classified Manager EEP Sundry Sales Dept. , Quadrant House, BRIAN DURRANT The Quadrant, Sutton, Surrey SM2 5AS. Tel.: 01-6613378. 01-6613106 Editorial & Advertising offices: Quadrant House, The Quadrant, Sutton, Surrey SM2 5AS. IAN FAUX Telephones: Editorial 01-661 3614. Advertising 01-6613130. 01-6613033 Telex: 892084 BISPRS G (EEP) Subscription rates: 1 years £15 UK and Production £ 19 outside UK. Student rates: 1 year £10 UK and £12.70 BRIAN BANÌ' ISI'hR outside UK. (Make-up and copy) Distribution: Quadrant House, The Quadrant, Sutton, Surrey SM2 5AS. 01-6618648 Telephone 01-6613248. Subscriptions: Oakfield House, Perrymount Road, Haywards Heath, Publishing Director Sussex RH16 3DH. Telephone: 04444 DAVID MONTGOMERY 59188. Please notify a change of address. USA: $49.40 surface mail, $102.60 01-6613241 airmail. Business Press International (USA). Subscriptions Office, 205 E. 42nd 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. of this e Business Press International Ltd 1985. appear at the back ISSN 0043 6062. issue.

www.americanradiohistory.com HA Fl MORE THAN JUST ONE STEP UP HM208 £1200. Dual Trace, Digital Storage 2mV - 20 V/crn 20 MHz Bandwidth Algebraic Add, Invert X - Y, Component Tester 4 Ik Stores, 20 MHz Clock, Roll, Refresh, Pre -trigger.

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Dual Trace 1 mV - 20 V/cm 20 MHz Bandwidth Algebraic Add, Invert X - Y: Single Shot Delay Sweep. Var Hold -off Component Tester HM203-5 £264. Dual Trace 2mV - 20 V/cm 20 MHz Bandwidth Algebraic Add. Invert X -Y Component Tester 2 Year Warranty H/=t1"IEC7 FOR THOSE WHO COMPARE 74-78 Collingdon St. Luton, Beds, LU1 1 RX Tel: (0582) 413174 Telex 825484

CIRCLE 121 FOR FURTHER DETAILS. PHILIPS PHILIPS AEL AT Philips Portable Computer P2000C ... an efficient IEC-Bus Controller SPEED with several advantages IEC-625/IEEE-488 protocol fully implemented TO BE CRYSTAL CLEAR IEC/IEEE programming made easy with extended MBASIC Tel. 029-34-5353 Telex 87116 Aero G and CP/M supplied with system MOD approved CAA approved bus analyser program included CIRCLE 68 FOR FURTHER DETAILS. for commercial use: Word processing, spreadsheet and information management programs also included the P2000C is a full -function, easy -to -use, inexpensive r---^ personal computer. RADFORD rCoupon > For more information and a demonstration 1 I III 111111 1111111111111111 POST COUPON TODAY Audio Measuring Instruments, uí Philips II 111111,,,1 Audio Amplifiers, Loudspeakers and Portable Loudspeaker Components for the II Name 1Uli Computer professional and enthusiast Address 11III101ii110 RADFORD AUDIO LTD. 10 BEACH ROAD Phone WESTON-S-MARE, AVON BS23 1AU TEL. Distributor in Great Britain: Kingsway Data Systems, 30 Guildford Street, 0934 416033 Chertsey. Surrey, United Kingdom, Tel.: (093 28) 68 911 CIRCLE 19 FOR FURTHER DETAILS. CIRCLE 125 FOR FURTHER DETAILS. 4 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com ri L_Lin 11I1j1'1U11II _ I Ì_ÌÌ griL_s1.

GANG -OF -EIGHT is our FAST EPROM PROGRAMMER which handles CMOS or NMOS EPROMS from 2716 to 27256 (25XX too) using FAST or NOFMAL 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-OFFSE-S 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 2'- 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 SOU RCECODE In Z80, 6502, 6803 or 8085 mnemonics. When your SCOPE or MULTI EIER can't find the problem - consult the MD. When you order say which processor or ask about multiprocessor MD . £295

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LOGIC ANALYSER TA2080 by THANDAR witt- 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 EPSON AND NEC COMPUTERS QX10, HX20 and PX8, PC8800. ALL COMPUTERS are sold with a free COMPUTERS bundle of useful software written by DATAMAN. OLIVETTI TYPEWRITER INTERFACES designec by DATAMAN for ET121 and 221 - cheaper than a DAISYWHEEL printer RS232, HPIB (IEEE) and FARALLEL 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 1RX. TELEX: 418442. PHONE (3305) 68066.

CIRCLE 60 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com NEWS COMMENTARY

biological mechanisms, we must assert, like Kierkegaard's 'leap Electro-reductionist challenge of faith', that it is equally valid to describe human life in of this biological modelling. Professor Donald Michie, a This journal has more than once subjective terms commented on to Apart from these specially researcher in machine - the threat consciousness, mind, intention, models, set up as aids intelligence, these new human life and ways of life designed volition etc. with the by certain of to research, there are the machines will function at "a - posed applications of moral choice that higher level of freedom electronics. There is now analogies suggested by existing these entail. another, different kind of threat artefacts. At one time the brain conceptualization" than is from this technology. It takes and central nervous system was possible with the existing Community radio the form of a challenge to our likened to a telephone Turing/von Neumann type understanding of what it is to exchange. Now it's a computer. computers. As an example, The Home Secretary has given the go-ahead for the be a human being. Of course, these popular research is being done on establishment of a number of Through a remarkable ability analogies are simplistic and distributed associative low -powered v.h.f. local radio to simulate natural phenomena misleading if pressed too far. memories modelled on what is stations, serving the and processes as well as man- But they have nevertheless known of human memory community. There is to be an made systems, electronics entered the folklore by their processes. inquiry into the ways of technology is providing emotional effect, especially Electro -reductionism, as it implementing such a service. At powerful for the when more and more human might be called, supports the the same time, there is to be a support clamp -down on pirate radio reductionist view of living tasks are being performed by instrumental view of human life stations which are using beings. Reductionism, put electronically controlled epitomised by behaviourism and frequencies likely to be crudely, is 'nothing but-ery.' machines. Current discussions the technological fix. It is a allocated to community radio. We are arrangements of atoms on whether such machines challenge that must be met. It We published an article by and molecules - machines - 'think' and have 'consciousness' puts us on our mettle to defend Norman McLeod, which functioning according to are largely exercises in and reaffirm our inner described a method for the best beliefs and values. utilization of wavebands for physical laws (which most of us semantics. But the very fact of experiences, community radio, in our July accept) and 'nothing but' such discussions by Faced with the blind 1983 issue. machines (which many of us professionals, like those on determinism of our own vehemently reject). nuclear war, makes the subject This is not a doctrine to be thinkable. easily dismissed. The At the lowest level, although philosopher John Searle in his brains don't actually work like 1984 BBC Reith Lectures computers, "the union of nerve The world needs admitted: "I just cannot square fibres by synapses into systems my conviction that I am a free with given overall properties" agent with my conviction are realistically comparable with more telephones that... the surface features of man-made "nets containing phenomena are explained by the cycles" (quoting from Norbert There is a gross imbalance in Germany, Morocco, France, behaviour of micro -elements." Wiener's Cybernetics). But now the distribution of telecommu- Tanzania, Venezuela, Gabon, The first electronic simulators that the fifth generation of nications across the world. Senegal, Romania, Indonesia, were analogue computers, and computers is almost here, the Three-quarters of the 600M the USSR, Costa Rica and Saudi electronic analogues are still model becomes more telephones in the world are Arabia and was chaired by Sir used to model living processes sophisticated. Aided by concentrated in only nine coun- Donald Maitland, the UK such as the electrical activity in cognitive psychology, it moves tries. Half the world's popula- representative. tissue-s. Now, digital computer a step nearer to the living tion live in countries with less Their chief conclusion is that programs are taking over some processes. According to than one telephone for every the industrial nations and 100 persons and in such coun- telecommunications industries tries these are predominantly should aid the poorer nations in concentrated in urban areas, in the development of their many rural and remote areas telecommunications. This will there are no telecommuni- promote the shared interest in cations at all. There are more that a more comprehensive telephones in Tokyo than in the world network will increase whole of Africa. One can only international traffic and speculate on the extent to generate funds for investment; which the absence of telecom- trade and other contracts would munications has contributed to be stimulated and the standard the disastrous famine in and quality of life of countless Ethiopia. millions would be raised to the These are some of the start- general good. The high ling facts which come from the technology and other industries findings of the Independent will then find new markets in Commission for World Wide the developing world for their Telecommunication Develop- products and their expertise. If ment, set up by the Inter- this common interest is national Telecomminications recognised and if higher priority Union. In their newly published is given to investment in Report the Commission has telecommunications as an made several recommendations integral part of the process of development, there is no good "We're hoping to get rid of the dongle when it goes into to the ITU. The Commission's production" members came from India, the reason, in the Commission's USA, Kuwait, Japan, Federal view, why be the early part of ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com the next century all mankind countries disinterested advice of should not be within easy reach the highest quality on every of a telephone. This is the aspect of creating and operating A source for neutrons objective set by the an effective system; and an What is claimed to be the pulses of neutrons emerging Commission. Operations Support Group world's most powerful pulsed from the moderators, now In practical terms the which would provide specific neutron source is to be fully comparatively slow in particle Commission proposes the assistance and complement the commissioned in April. The terms, are used for setting up of a Centre for work of the Technical Co- Spallation Neutron Source experimental purposes. Telecommunications operation Department of the (SNS) is at the SERC Neutrons carry no electrical Development. It would have ITU. Rutherford Appleton charge and can penetrate an three components: a Although the Commission Laboratory. Initial tests have atom and interact with the Development Policy Unit, to accepts that there is no instant found it to be a very useful tool neucleus. Because they have collect and disseminate solution, if their and a small but significant wavelengths which range from information about recommendations were to be discovery has been made in the less than the dimensions of an telecommunications policies and accepted and implemented with distortion of the structure of atom to that of large molecules, experience; a vigour, the world wide situation nickel oxide. the neutron beams can be used Telecommunications could be transformed within 20 The initial test consisted of to probe the structure of Development Service which years. accellerating protons to molecules and the arrangement would offer developing 550MeV in a sychrotron of atoms and molecules in (800MeV will be used crystals, liquids, glasses and eventually). The protons are plastics. One example is extracted from the synchrotron investigate the structure of in high intesity bursts, 50 times viruses. Neutrons are very a second, and are focused on a penetrating and can be used to UK's the place for target of non -fissile Uranium probe the internal structure of 238 where 25 to 30 neutrons bulk materials, for example are released for each incident studying the setting of cement US hi -tech proton. The pulsed structure and internal strains in metals. allows the measurement of Neutrons have relatively low Geoffrey Pattie, who took over If these restrictions are neutron wavelength and energy. engergy; about 10 times less the Ministry for Information allowed to grow unchecked, the The neutrons so generated are than that of X-rays of Technology has been exhorting long-term effect could well be a too energetic and are therefore comparable wavelength. This Americans to locate their high decline in the quality and a slowed down by 'moderators' of allows the investigation of technology industry in Britain. decrease in speed of scientific which the SNS has four: two of atomic and molecular motion Addressing the annual meeting and technoligical progress; and water at room temperature, one within substances which in turn of the American Friends of the increased risk of duplication of liquid methane at 100K and give information about the Wilton Park, in Los Angeles, he of effort. one of hydrogen at 25K. The atomic -scale forces which pointed out that the UK consumption of integrated circuits alone grew 50% last year, to £450M. "The UK is now the largest European market for i.cs. It is also the fastest growing and uses a higher proportion of integrated circuits in its products than any other European country." He outlined the Governments' work in telecommunications and particularly the development of the TACS cellular radio system which should give 90% of the UK population the opportunity of making telephone calls from their cars by 1990. In another In another part of his speech he decried the US restriction om the dissemination of unclassified technical data and scientific information. "Such moves have included the withdrawal of scientific and technical papers from open circulation; limitation on the attendance of non -US citizens at scientific conferences; restrictions on US scientists A prototype of what is said to be the first mobile satellite communications wishing to attend international ground station from Racal -SES. The company are to supply the MoD with a conferences; and restrictions on number of such stations for use in military communications from a forward the access of foreign students to headquarter position. US laboratories.

ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com NEWS COMMENTARY

control the structure and magnetic properties of properties of matter. They also materials. The first? Communi- provide the basis for the newly This combination of all the developing technique of neutron various properties of the radiography. Each neutron has neutron make it a powerful and Not by a long cations for magnetic moment; it behaves unique tool for a wide range of like a tiny magnet, and may be studies in chemistry, physics, chalk the deaf used in the study of the biology and materials science. Whenever we take the words of A profoundly deaf young mother a press release for granted, we from Leeds has called on the are invariably wrong. Philips Government to provide financial Ten -four breakers? told us that their slow -scan tv assistance to enable similarly system was the first to get BT handicapped people to benefit It appears that the old illegal CB fixed. Some channels at the approval (January News). Not from electronic mail. Doreen radio rigs will soon become bottom of the band are still so, says Ibsonmain of Naylor, deaf from birth, has as legal but the new legal sets will occupied by such services Uxbridge. They had approval contributed to a book, Micros at the same time become hospital paging systems and back in 1978 when BT was still for the Handicapped. She runs a illegal. The Radio Regulatory most of these have been part of the GPO. They claim network linking deaf families in Division or their masters at the allocated new channels in Band that they were the first and Leeds and Bradford and is DTI have agreed to adopt the III following the demise of the know of at least three other particularly pleased with the frequencies recommended by 405 -line tv service. But companies in the same field Commstar rom from Pace which the CEPT for use in Europe. eventually CB users will have to with official approval. Ibsoscan she uses in her BBC micro, These are the same as the get new equipment or have H is a transceiver that will also along with a Pace modem. American FCC allocated their rigs modified to remain autodial, autoanswer, provide Doreen is one of several frequencies for CB and were legal. The 934MHz band is to remote control of cameras, handicapped people who have used illegally in this country be moved down by 12.5kHz alarm systems etc. Its built-in written first-hand accounts of until parliamentary lobbying, with the channels spacing line monitoring ensures privacy their experiences in the book, and widespread flouting of the reduced in order to get 40 and there is no limit to the published in Whitby by Helena law, forced the Government channels on this band. After all length of time a transmission Press. into making CB legal. The this has happened breakers will will take. Moreover the product official reason given is that the be able to use their sets all over is British designed, British frequencies allocated on Europe and it is presumed that made and built almost entirely legalization were the only ones as they all seem to of British components. useable in the short time -span communicate in their own weird Alvey looks then available. The CEPT language they should have few recommendation allows for a linguistic problems there. 40 -channel service operating Perhaps that is what Orwell at wafers between 26.96 and 27.40MHz meant by Newspeak? Our A major project for developing with four watts power and using thanks to Reg Moore, G3GZT/ Automatic fault -tolerant design techniques f.m. only. There is to be a VS6CD, for pointing out this for wafer -scale integration. gradual changeover with the addition to the CB snafu saga. telephone Plessey, GEC and ICL are to final plans and dates not yet collaborate with Brunel University, Middlesex fault-finding Polytechnic and King's College, In British Telecom are installing London in the project. It is brief automatic line testing planned to take three and a half STC think they can find a niche Engineers at the IBA equipment to speed telephone years and involve a total of 50 in the market by providing a Engineering Centre have fault detection and repair. years' effort for one person. connector service. With this in successfully received from Beginning in March the The objective is to create mind they have set up a new Norway the first operational equipment will be installed in circuits which can be company; Five Star Connectors, service to use the C-MAC/ about 100 of BT's 360 repair reconfigured to avoid defects on and have invested several packet d.b.s. system. The service controls. It will the wafer. Several approaches million in buying stock, so that pictures are being transmitted automatically test customers' have been proposed, but few a -day, off- Norwegian they can offer same by NRK, the lines and equipment overnight tested in practive. Such a self - the -shelf service for a wide broadcastine corporation for to spot any degradation before repair system has been variety of connectors from a reception in the Svalbard it develops into a fault which described by Ivor Catt in this number of leading Islands off the northern coast of could affect telephone service. journal. For the Alvey project it manufacturers. Coinciding with Norway, well within the Arctic It can also be operated by is planned to produce two the launch of the new company Circle. This is the first service officers at the control centres in circuits, one will have a regular is the first issue of their to use the C-MAC/packet reply to faulty line calls by array structure while the other EBU catalogue; 104 pages long and system proposed by the users dialling 151. being a non -regular cell -based seemingly covering any and based largely on the MAC Eventually the records and type. C.mos technology is to be connector that one could system developed by the IBA. automatic test computers will used for these demonstration imagine. The Norwegians are using the be integrated so that if a fault is wafers. The project part of the Since the poison gas disaster eight sound channel capacity reported, the customer service overall VLSI architecture to in Bhopal, India, the Ever available in the specification operator can call up the line's programme of Alvey which aims company wish it two radio Ready battery provide stereo previous fault record, initiate to produce a variety of methods to be known that they have no channels in addition to the the automatic test and read the for exploiting the possibilities of connection with Eveready sound accompanying the results displayed on a screen. parallel processing offered by batteries marketed in several picture. IBA engineers are This will usually provide enough VLSI. The WSI project should countries (though not in the currently working on an information to estimate the time produce manufacturing of UK) by Union Carbide. experimental enhanced form needed to effect the repair and techniques of value to all wide-screen MAC transmission. organize an engineer's visit. designers of VLSI circuits. 8 ELECTRONICS & WIRELESS WORLD MARCH 1985

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

500 VA 15 VA 50 VA 120 VA 225 VA x 1.2Kg 110 it 45mm 2.2Kg 140 x 60mm 4Kg 62 x 34mm 0.35Kg 80 x 35mm 0.9Kg 90 40mm Why a Toroid? Regulation 11% Regulation 7% Regulation 4% Regulation 19% Regulation 13% Smaller size & weight to meet 6x012 12+12 9.38 8x016 25+25 10.00 2x010 6+6 4 16 4,010 6+6 10.00 SERIES SECONDARY RMS 15+15 750 30+30 833 modern 'sl i m l i ne' requirements. 9+9 2 77 4x011 9-9 6.66 6+013 8x017 No Vows Current 2x011 18+18 6.25 6x018 35+35 714 2x012 12+12 2 08 4x012 1212 500 6x014 Low electrically induced 6+015 22+22 5 11 8+026 40+40 6.25 0x010 6+6 1 25 2x013 15+15 1.66 4x013 15-15 4.00 25+25 4.50 8x025 45+45 5.55 noise demanded by compact 0x011 9+9 083 2x014 18+18 1.38 4+0.14 18-18 3 33 6+016 30+30 3 75 8x033 50+50 500 0x012 12+12 0.63 2x015 22+22 113 4x015 22.22, 2 72 6x017 equipment. 6x018 35+35 321 8x042 55+55 4 54 0x013 15+15 050 2x016 25+25 4x016 25+25 2.40 High efficiency enabling 16 40+40 2.81 110 4 54 0x014 18+18 0.42 2x017 30+30 0 83 4x017 30+30 2.00 6x026 8+026 6,025 45+45 2.50 8+029 220 2 27 conservative rating whilst main- 0x015 22+22 0 34 2+028 110 045 4+018 35+35 1 71 50+50 2 25 240 2 08 0x016 25+25 0.30 220 0 22 4+028 110 1.09 6x033 8x030 taining size advantages. 2x029 110 2.04 0,017 30+30 0 25 2x030 240 0 20 4x029 220 0 54 6x028 220 1.02 625 VA Lower operating temperature. 4+030 240 0.50 6x029 5Kg (encased in ABS plastic) 80 VA 6x030 240 0.93 140 x 75mm 160 VA Regulation 4% 90 x 30mm 1 Kg 30 VA 110 x 40mm 1.8Kg 300 VA Why ILP? Regulation 12% 9x017 30+30 1041 70 x 30mm 0.45Kg Regulation 8% 110 x 50mm 2.6Kg Regulation 18% Regulation 6% 9x018 35+35 8 92 Ex stock delivery for standard 3x010 6+6 6 64 5x011 9+9 8 89 9x026 40+40 781 9+9 4.44 10 1x010 6+6 2.50 3x011 5x012 12+12 6 66 7x013 15+15 00 9x025 45+45 694 240V range 3,012 12+12 3.33 5x013 15+15 5.33 7+014 18+18 8 33 50+50 625 1x011 9+9 1 66 9x033 3+013 15+15 266 18+18 444 7+015 22+22 6.82 55+55 568 *Fast prototype service available 12+12 1 25 5+014 9x042 1x012 18+18 222 1+013 15+15 1.00 3+014 5+015 22+22 363 7+016 25+25 6.00 9+028 110 568 3 weeks despatch for special 3x015 22+22 181 1+014 18+18 0 83 5x016 25+25 320 7+017 30+30 5 00 9+029 220 584 orders 25+25 160 1+015 22+22 0 68 3+016 5+017 30-30 2.66 7x018 35+35 4 28 9+030 240 2 60 30+30 1 33 year no quibble guarantee 1.x016 25+25 0 60 3+017 5,018 35+35 228 7+026 40+40 375 *2 110 0.72 1+017 30+30 0 50 3x028 5+026 40+40 200 7+025 45+45 3 33 ' No price penalty for 0 3x029 220 36 5+028 110 1 45 7+033 50+50 3 00 3+030 240 0.33 5+029 220 0.72 7+028 110 2 72 call -oft order 5+030 240 0.66 7+029 220 1.36 7+030 240 1 25

Mail Order - Please make your crossed Prices including P 8 P and VAT Post ILP Electronics Ltd., Dept, 3 cheques or postal orders payable to I LP to: VA Size VA Size Electronics Ltd. Graham Bell House, Roper Close, 15 0 7.06 160 5 12.17 Trade - We will open your credit account Canterbury, Kent. CT2 7EP 1 7.67 225 6 13.75 30 immediately upon receipt of your first 50 2 8.90 300 7 14.97 Tel: (,0227) 454778 Telex: 965780 90 3 10.06 500 8 19.60 order. 120 4 10.65 625 9 22.30

For 110V primary insert "O" 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. VISA IMPORTANT: Regulation - All voltages quoted are FULL LOAD. Please add regulation figure to secondary voltage to obtain off load voltage. ELECTRONICS LTD. CIRCLE 41 FOR FURTHER DETAILS.

A GENUINE OPPORTUNITY TO PURCHASE THE AUDIO ROBOTS DISTRIBUTION CONSOLE For Education, Training and Industry

NEPTUNE I NEPTUNE II' Kit NEPTUNE - for clean MODEL from hydraulic power - Kit £1250 - tap water is the from RTM4-100 hydraulic fluid! £1725 SYSTEM SPECIFICATION DISTRIBUTION FACILITIES The following distribution facilities are provided.

1. Single channel radio distribution from integral variable AM/FM tuner.

2. Single channel cassette tape distribution from integral cassette player.

3. Four channel mixed speech distribution from any standard 200 ohm impedance microphones.

Note that the output of all facilities can be mixed if required and that bass and treble control is provided on the MENTOR mixed output. Kit from RECORD FACILITY £345 The integral cassette tape recorder can be used to record the mixed output of the four microphone channels and the radio distribution channel.

CONSOLE

DIMENSIONS: 465mm High x 435mm wide x 330mm deep approximately NEPTUNE 16 axes; 8 bit control system; 2.5Kg Robots may also be taught by 'lead by the POWER SUPPLY: 200/250 Volts A.C. 50 Hz. capacity; 1120mm reach. nose' method. AMPLIFIER: 100 Watts RMS Extensive software Is supplied free line NEPTUNE II 7 axes; 12 bit control system; with 100 Volt output each robot. 2.5Kg capacity; 1 120mm reach. Leads available for connection to BBC, ZX PRICE £556 inc VAT and Delivery (Mainland only) MENTOR DC servo desktop robot; 8 bit Spectrum, Apple Ile, Commodore 64 and Weight: 28 Kilos Nett, approx. control system; 3009m capacity; 420mm reach. VIC 20. TERMS C.W.O. export enquiries welcome. We find it impossible to advertise at we stock. Please Robots programmed from keyboard or hand- Most other micros are also easily usable with telephone, write or telex for further enquiries. Personal callers always welcome. held simulator (model robot). these robots.

Or e Please phone for brochure: 0264 50093. SPRINGFIELD HOUSE, co West Portway Industrial Estate, Andover SP 10 3 WW. TYSSEN STREET, LONDON E8. 2ND ybnrnn Ic A private independent company giving prompt. and ELECTRONIC EQUIPMENT CO. TEL NO. 01-249 5217 pplicatians personal service. TLX: 8953906 EECO G

CIRCLE 17 FOR FURTHER DETAILS. CIRCLE 124 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MARCH 1985 9

www.americanradiohistory.com Electronic Brokers Test & Measure CHECK OUR Thandar SC 110A £175 Fluke 80248 £220 Thander TM 355 £85 OSCILLOSCOPES & 10MHz, battery powered portable, bright line 3112 digit. LCD, eleven functions include peak hold 312 digit, 0.5" bright LED, 29 ranges of and economy triggering for battery conservation, on voltage and current, audible and visual logic measurement. DC accuracy 0.25%, battery or LOGIC ANALYSERS TV frame and line triggering. Sensitivity 10mV level detection. CC accuracy 0.1%. mains operation, diode check. supplied with test to 50V Fluke 80268 £172 leads 3112 digit, LCD, eight functions include Philips PM 3267 £1250 conductance. audible continuity, true RMS, DC 100MHz, dual trace, main and delayed time accuracy 0.1%, all 20 series DMMs have 2 year bases with independent triggering, 2mV warranty. sensitivity, trigger-view as third channel display ï'3Út1111,t1f'1 Fluke 80208 £173 Philips PM £1325 ao 3256 ìi'íli 3112 digit, LCD, eight functions include 75MHz, compact ruggedized portable with conductance, diode test, audible continuity, DC shoulder strap, dual trace, 2mV sensitivity, ááìhteKIFiF------+ accuracy 0.1%, extensive over -load protection delayed time base, trigger -view, TTL triggering rcr; Flki ke 8021B £ 139 Philips PM 3217 £870 3112 digit, LCD, seven functions include diode test 50MHz, dual trace, delayed time base, 2mV 4111,11111111mi and high speed audible continuity. DC accuracy sensitivity, TV triggering on line and frame, 0.25%, safety test leads provided. Thurlby 1905A £325 variable hold -off. Z modulation. Fluke 80228 £114 5112 digit, bright LED, 1NV, 1 mn, 1 nA sensitivity, Philips PM 3215 £695 3112 digit. LCD, six functions include diode test. DC accuracy 0.015%, null and hold functions, 50MHz, dual trace, single time base, 2mV Thandar TA 2160 £3450 DC accuracy 0.25%, optional accessories computing functions, true RMS and IEEE sensitivity, TV triggering, auto triggering with 16 channels, 20MHz logic analyser, 15nS glitch available to enhance all OMM measuring interface options. level control, X -Y operation. capture. 252 word data and reference capabilities. Philips PM 3207 £325 memories. automatic or manual compare Fluke JF 77 £110 15MHz, dual trace, light -weight portable, 5mV between memories, personality options 3'12 digit, LCD with analogue bar graph, ANALOGUE MULTIMETERS sensitivity, auto triggering from either channel. Philips PM 3302 £1395 auto/manual ranging, DC accuracy 0.3°I°. touch add and invert mode. X -Y operation. 20MHz Digital Scope, 2 Channels. OC-20MHz, and hold facility, supplied with carrying holster 1mV/cm sensitivity. Single & X -Y operation. Fluke JF 75 £88 Philips PM 2505 £151 3112 digit, LCD with analogue bar graph, 62 measuring ranges. 10Mn input impedance. auto/manual ranging, DC accuracy 0.5%, seven linear resistance ranges, audible continuity, functions include diode test and audible automatic polarity indication, low power BENCH & HANDHELD continuity. consumption DMMs Fluke JF 73 £72 I.C.E. 68014 £32 3'12 digit, LCD with analogue bar graph, auto 80 measuring ranges. sensitivity 20Kn/V. DC ranging, DC accuracy 0.7%, six functions accuracy 1%, 12cm mirror scale. overload include diode test, all 70 series DMMs have 3 protection. year warranty. I.C.E. 680G £25 Fluke JF 25 £193 48 measuring ranges, sensitivity 20Kn/V. DC 3'12 digit, LCD with analogue bar graph, sealed accuracy 2%, 10cm mirror scale, overload ruggedized construction, auto ranging, DC protection. accuracy 0.1%, touch -hold facility, extensive I.C.E. M80 £19 overload protection. 40 measuring ranges. sensitivity 20Kn/V. DC accuracy 2%, wide range of accessories extend Philips PM 3206 £275 measuring capabilities 15MHz, compact portable, dual trace, 5mV sensitivity. auto and TV triggering, variable time base speed, Z modulation. PULSE, FUNCTION, Philips PM 3219 £2675 50MHz. analogue storage with variable PATTERN GENERATORS persistence, auto erase and auto store facilities, 2mV sensitivity, delayed time base. Philips PM 2519/01 £285 Philips PM 5712 £940 Hameg HM 605 £515 4112 digit. LCD with analogue bar 60MHz. dual trace, sweep delay, maximum graph, auto/manual ranging, Hz to 50MHz, 4nS, amplitude 200mV to 10V, sensitivity 1mV, versatile triggering. frequency to 1MHz. true RMS, dB, pulse duration and delay 10nS to 100mS, double, Z modulation. X -Y operation, inbuilt componen relative reference. PM 2519/51 with normal or inverted pulse. ext triggering sync tester. IEEE interface E495. gating, single shot. Hameg HM 204-2 £365 Philips PM 5326 £1129 20MHz, dual trace, sweep delay. maximum Philips PM 2518X/11 £199 RF generator 100kHz to 125MHz, AM/FM sensitivity 1mV. variable hold-off, X -Y operation, Fluke JF 27 £216 modulation, 5 digit counter displays RF carrier, 4 digit. LCD with electroluminescent ruggedized Z modulation, component tester. display. auto/manual ranging, true 3'12 digit, LCD with bar graph, marker and external frequencies. 50mV RF MS, dB. relative reference, current construction, auto ranging, DC accuracy 0.1%, output at 75n. to 20A touch -hold facility, min -max and relative mode operation. Fluke 8050A £364 Thandar TM 351 £115 4112 digit, LCD. nine functions including dB, 3'12 digit, LCD, 29 ranges of measurement, DC conductance, diode test, true RMS, relative accuracy 0.1%, diode test, battery life typically reference, DC accuracy 0.03%. 8050A-01 4000 hours, complete with batteries and test Ni -Cd battery version 0399. leads. Fluke 8012A £324 3112 digit, LCD, low ohm resistance range, seven functions include conductance, diode test, true RMS, DC accuracy 0.1%. 8012A-01 Ni -Cd battery version 0358. Fluke 8010A £243 Philips PM 5134 £1415 Function generator 0.001 Hz to 20MHz. 3'12 digit, LCD. 10A current range. seven frequency functions include test, true display, sine, square, triangle, TTL, int conductance, diode or ext sweep, modulation, output 20Vpp. RMS. DC accuracy 0.1%. 8010A Ni -Cd battery AM/FM version 0279. Philips PM 5133 £1085 Fluke 8060A £306 Function generator 0.01 Hz to 2MHz, frequency Hameg HM 203-5 £264 4112 digit, LCD, ten functions include display, sine, square, triangle, TTL, int or ext 20MHz, dual trace, add and invert, maximum conductance, diode test continuity, dB, sweep, log or lin, output 20Vpp, selectable 50n sensitivity 2mV, automatic and normal frequency. true RMS. DC accuracy 0.04%, or 60()n. triggering. X -Y operation, component tester. relative reference mode Thandar TM 451 £195 Philips PM 5132 £595 Hameg HM 103 £167 Fluke 8062A £245 4'12 digit, LCD display with function legends. Function generator 0.01 Hz to 2MHz. sine. 10MHz, single trace, maximum sensitivity 2mV, 4112 digit, LCD, seven functions include diode auto/manual ranging, DC accuracy 03%, square, triangle, TTL, positive and negative TV triggering, compact size, component tester, test and continuity. relative reference, DC sample/hold facility on all ranges, audible pulses, int or ext sweep, output 30Vpp, all Hameg oscilloscopes haveTHEN 2 year warranty. accuracy 0.05%. true RMS. self diagnosis test. continuity.CHECK selectable 50n or 600n. Electronic Brokers are leading suppliers of Thurlby, GP Industrial, Claude Lyons, Coline, Compact electronic test and measuring equipment. Our Instruments. distribution division handles the major names in These products are stocked in depth in our the industry: Philips, Fluke, Hameg, ICE, Thandar, spacious new premises at Camden Town, ready for

r L ) )

L L

) Electronic Brokers t ) CIRCLE 200 FOR FURTHER DETAILS. lU ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com ment Instrument Distribution Division INVENTORY: Philips PM 5131 £395 Philips PM 6671/01 £719 Function generator 0.1Hz to 2MHz, sine. Counter/timer, 0.1Hz to 1201.4Hz, as PM 6670 MISCELLANEOUS LINE CONDITIONERS square, tri -angle, TTL, int or ext sweep, output with LED trigger indicators, trigger level outputs, 3OVpp into 50n, stepped and variable burst frequency average, arm ng, ext PRODUCTS attenuation, reset/start, gate open monito' Claude Lyons LVC 500 £330 Philips PM 6303 £695 5A, 1200VA rating, line voltage conditioner, RCL bridge, 4 digit LCD display supply frequency 48-63Hz, incorporate ultra Philips automatic isolation an f.i. filter. for measured value and electric dimension, transformer accuracy 0.25%, automatic or stepping parameter menu selection. Philips PM 6307 £457 Philips wow 5 flutter meter, crystal controlled oscillator. 3150Hz and 3000Hz selectable, high accuracy and stability, separate drift and flutter indication.

tt Philips PM 6672/01 £887 Counter/timer, 0.1Hz to 1GHz. period, pulse Philips PM 55191 £785 width, single and average time interval, count, Pattern generator, 20 combination test phase. RPM, ratio, high resolution. 10mV £256 patterns, full RF coverage, electronic tuning with sensitivity to 70MHz. Claude Lyons LVC 250 6 preset channels, video and sound mod, comp Philips PM 6668/01 £446 2.5A, 600VA rating, line voltage conditioner. and frame sync. fast response (typically 1'I2 cycles), isolated Counter, 10Hz to 1 GHz. 7 digit LCD display, Philips PM 5503 £145 input/output, compact and portable for easy auto triggering on all waveforms, 15mV installation. Pattern generator, 5 testpatterns for mono and sensitivity, high stability crystal oscillators. LVC 65 . £175 colour, video output for CCTV and monitors, RF Philips PM 6667/01 £304 Claude Lyons in range. 1 kHz tone for 0.65A, 156VA rating, line voltige conditioner. output VHF and UHF Counter, 10Hz to 120MHz, 7 digit LCD display, Thandar TH £80 sound checks. 302 unaffected by frequency variations, transient self diagnosis routine, auto triggering 15mV Thandar digital thermometer, LCD display of °C TG £110 and noise suppression. All LVC units have 2 ye< Thandar 101 sensitivity, high stability oscillator. and °F, rave -40°C ta 1100°C, resolution warrantly, Function generator 0.02Hz to 200kHz, sine, 0.1° and 1', for use with type K probes (bead square, triangle, variable DC offset, TTL output, supplied). external sweep, 1OVpp output into variable 600n. EPROM PROGRAMMERS Thandar TO 102 £160 Function generator 0.2Hz to 2MHz, sine, square, triangle. TTL output, variable DC offset. external sweep, 20Vpp output into variable 50n Thunder TG 105 £105 EyEcs Í Pulse generator 5Hz to 5MHz, 10nS, amplitude p 0.1V to 10V into 50n, free -run. gated or Thandar TF 200 £175 TTL output, pulse width Í triggered modes. Counter, 10Hz to 200MHz. 8 digit LCD, battery mime variable 100nS to 100mS. powered. 10mV sensitivity, time average period. Thandar TG 501 £295 totalize and reset. TP 600 pre -scaler, 40MHz Function generator 0.005 Hz to 5MHz, sine, to 600MHz available at E45. square, triangle, ramp, pulse, TTL, variable DC Thandar PFM £76 £169 phase. 20Vpp into 200A Thurlby OM 358 offset, variable start/stop Counter, 20Hz to 200MHz, 8 digit bright LED, any oscilloscope to variable 50n Thurlby multiplexer expands P £1295 battery powered, 10mV sensitivity, resolution 8 channels, displays analogue or digital signals, GP Electronics 903 ' Thandar TG 502 £495 EPROM programmer. 16 character fluorescent. 0 1 Hz, selectable gate times, mains adaptor and triggering from any channel, band width 35MHz, Sweep/function generator 0.005Hz to 5MHz, TP 600 pre -scaler available. precision calibrated attenuator. message display, menu selection programmes sine, square, triangle, TTL, internal sweep log or all EPROMs, powerful editor, RS232C interface. lin, variable sweep rate and marker duration, label print feature. sweep and pen -lift outputs. GP Electronics P 9020 £995 POWER SUPPLIES EPROM programmer, 16 character display, menu device/mode selection, programmes all single rail EPROMs, RS232C. inc vidual device Thurlby PL 154 £149 pass/fail indication. 0 to 15V, 0 to 4A. bench power supply, twin LED displays meter voltage and current, high stability and resolution, remote sense facility.

Thurlby CM 200 £89 Thurlby diggital capacitance meter, 4'12 digit LCD, 1 pF to 2500,F range, accuracy 0.2%, fast Thandar TG 503 £495 settling, battery or mains operation. Pulse/function generator 0.005Hz to 5MHz. sine, square, triangle, ramp. TTL, normal, double GP Electronics MFL 373 C695 or delayed pulses, variable pulse width and delay, Microsystem fault locator, range functions adjustable base line. include Bus test, ROM test, dynamic and static RAM test, supplied with synchrous logic probe GP Electronics UV 141 £88 COUNTERS & Thurlby PL 320 £145 EPROM eraser, variable electronic timer, 0 to 30V, 0 to 2A, bench power supply, constant powerful UV source, up to 14 device capacity. COUNTER/TIMER current or constant voltage, precise current limit convenient tray loading with safety interlock. control and monitor system, ripple and noise 1 mV. Philips PM 6670/01 £593 Thurlby PL 310 £118 Tachoprobe £70 Full specifications on any Counter/timer, 0.1Hz to 120MHz, period, pulse 0 to 30V, 0 to 1A, bench power supply. meter Compact tacho -probe for use with DMMs or products distributed by width, single and average time interval, count, accuracy 0.1%, resolution 0.01V and 0.001A, frequency counters, 2 speed ranges from 100 are phase. RPM, ratio, high resolution, 10mV DC output switch, load regulation <0.01% for to 20,000 RPM, accuracy 1%. non-contact Electronic Brokers sensitivity. 50% load change. range 1m. available on request. OUR SERVICE. prompt despatch to all parts of the country. Visitors are welcome to our showrooms where Electronic Brokers offer full technical support all products are on display and demonstration. and expert advice on all aspects of electronic test For customers wishing to order by phone, we offer and measuring. a 24 hour answering service.

Electronic Brokers Ltd 140-146 Camden Street All prices exclusive of VAT. Carriage and packing charges extra on all items unless otherwise stated. London NW1 9PB A copy of our trading conditions is available on request. Prices correct at Telephone 01-267 7070 Telex 298694 time of going to press.

CIRCLE 200 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com SUPER HY-UGHT STROBE KIT VARIABLE VOLTAGE TRANSFORMERS Superior Quality Precision Made Designed for Disco, theatrical uses, etc. Approx. 16 joules. Adjustable speed. Price £45 C2 p&p (Total inc. INPUT 230, 240V a.c. 50/60 OUTPUT 0-260V. NEW POWER RHEOSTATS VAT £54.05; Case and reflector price £15 + £2 p&p (total inc. VAT 200W, to Max. £15.00 £19.55): Foolscap SAE for further details including Hy -Light and 0.5KVA212A Max. £19.00 New ceramic construction, heavy duty brush Industrial Strobe Kits. 1KVA 5A Max. £27.00 assembly, continuously rated. 2KVA 10A Max. £41.00 25 WATT 5/10/25/50/100/150/250/300/500/1kt3 ULTRA VIOLET BLACK LIGHT 3KVA 15A Max. £54.00 1 .5kß £4.25 + 30p p&p. (£5.23 incl. VAT). FLUORESCENT TUBES 5KVA 25A Max. £9900 50 WATT 2504 £6.50+ 50p p&p (£8.O5 Incl. VAT). 100 411 40 wan £10.44 If1200 inc. VATI 10KVA 50A Max. £181.00 - WATT 1/5/10/25/50/100/250/500/1k4/1.5k4/2.5k2/3.5k4 15KVA 75A Max. £10.25 + 75p p&p 211 20 watt £7.44 El 25 p&p (699 inc. VATI £275.00 (12.65 Intl VAT) 18in 15 wan 6.00 75p p&p 16.61 inc. VAT) 3-PHASE VARIABLE VOLTAGE Black Silver Skirted Knob calibrated in Nos 1.9, 112i n. dia brass bush 13m TRANSFORMERS 10 wan £4.00 75p p&p 16.46 inc. VAT( Dual input 200-240V or 380-415V. Star connected Ideal for above Rheostas 30p ea. + VAT 121n 8 watt £3.60 + 50p p&p (£4.71 inc. VAT) 3KVA 5amp per phase max. £113.40 All V.V.Ts Tin 6 wan £3.00 + 50p p&p (£4.02 inc. VAT) 6KVA 10amp per phase max. £170.10 plus carriage em 4 wan £3.00. 50p p&p not inc. VATI 1OKVA 16amp per phase max. £345.45 and VAT INSULATED TESTERS NEW! Test to I.E.E. Spec. Rugged metal construction 230V AC Ballast Kit for either 6in, Oie or 12in tubes £5.50 p&p 55p Comprehensive range of TRANSFORMERS L.T. ISOLATION & AUTO suitable for bench or field work sperm If6.96 inc. VATI. (110-240V). Either cased with American socket and mains lead or onstant clutch. Size L Bin., W 4in., H 6in. weight 61h For 13in. & 18in. Tubes £6 p&p 75p (£7.76 inc. VAT). open frame type available for immediate delivery. Leaflet on request. For 12V DC op. 12ín. & 13in. tubes only £5.50 p&p 75p 1E7.18 inc. 500V. 300 megohms. £49 p&p E2 (£58.65 Inc: VATI 12V D.C. BILGE PUMPS VAT). 1000V 1000M0 E55 + p&p £21E65.551ocl 175 WATT SELF-BALLASTED BLACK UGHT MERCURY BULBS. 400 G.P.H. 15ft. head, 3amp, £8.00 a £1.00 p&p SAE for leaflet. 100 r 4.VAT) Available for either B.C. or E.S. fitting, price £10.80 + p&p £1.25 (total inc. VAT £13.85). 700 G.HG.P.H.01.h 10h. head, 3.5amp, £11.50 + £1.50 p&p 1E14.95 inc. VAT). 400W UV LAMP & BALLAST complete - £48.80 + p&p £3.50 (£52.30 t GEARED MOTORS Intl VAT) 1750 G.P.H. 15h. head, Vamp, £15.00.. £1.75 p&p 1£19.26 inc. VATI. 5 rpm 240V AC Mf. by Carter, 6.16 fl p&p 111811 Inc. VAT). N M S. 400w UV LAMP only, £20.00 + p&p £2.50 (£25.88 incl. VAT). 20 rpm 1151/ AC Synchronous, torque approx. 80Ib/in. £20.00 + 114 p&p (Total in( L.T. TRANSFORMERS SINGLE DIAPHRAGM COMPRESSOR NMS "

Max. 20 PSI. One GEM 240 volts A.C. £18 , £2 VATI. "Special Offer" 0 -6.3V -0-6.3V at 10 Amp (12V 0 10 Amp or 6V at 20 approx. p&p 1E23 inc. TRANSFORMER 240V operation. 6.15 r £2.00 p&p (Total Inc VAT £12921. Amp) Price £9.00 p&p £2.00 - inclusive of VAT £12.65 N.M.S. 71 rpm Torque 201b in. reversible 11 0th h.p. 110V AC. Price- £9.50 + p&p Cl 80 EPROM ERASURE KIT (Total inc. VAT £1299) ROBOT ENTHUSIASTS Why waste money? Build your own EPROM ERASURE for a Suitable TRANSFORMER for 230-240V AC operation. Price. 620 r p&p CI 40 The following two Motors are ideally suited for experimenters in fraction of the price of a made-up unit. Complete kit of parts less (Total inc. VAT £7591 NM S this field: case to include 12, 8 watt 2537 Angst. Tube. Ballast unit, pair of 383 rpm GEARED MOTOR. Torque 351b in reversible 115V AC Inc start capacha 1. ESCAP precision Swiss -made ironless rotor, 6V DC geared b. -pin leads, Neon indicator, safety microswitch, on/off switch Price £11.55 p&p (Total inc. VAT £15.58). N.M S MOtor with 70-1 gearbox. 6V DC -16 r.p.m. 3V -8 r.p.m. amazing and circuit. Suitable TRANSFORMER 230V AC operation. Price £5.20 o 50p p&p (£8.58 incl power: no load current; only 10 ma. approx. Size: 4 x 21 cm. Ex - LESS CASE: Price £13.60 + 75p p&p (Total inc. VAT £16.50). VAT) equipment, tested and guaranteed. ONLY £4.50 + 50p p&p (total Warning: Tube used in this circuit is highly dangerous to the CROWN 37 rpm 2000lb it approx. 110V AC. reversible geated motor Price £35 inc. VAT £5.75). eyes. Unit must be fitted in suitable case. p&p £4.50 1E45.42 inc. VATI N.M.S 2. 12/24V D.C. Reversible Precision built motor manufactured by Suitable TRANSFORMER for above £10 p&p £1.50 Ií1322 oc VAT) Escap - will operate from 24V down to 2V DC- Current consump- SOLID STATE E.H.T. UNIT 57 rpm 240/1 1/22 h.p. continuously rated REVERSIBLE 50115in manuf by tion negligible. A range of speeds between 2 to 36 r.p.m. 230V A.C. 15KV. Input Approx. Producing 10mm spark. Built-in 10 sec Wynstruments.New. Ideal for garage doors. curtains etc ONLY £72.00 . (200 obtainable: 6 DC r.p.m. N/L 6 MA, 12V 18 r.p.m. N/L 10 Volt -9 DC- timer. Easily modified for 20 sec, 30 sec. to continuous. Designed for p&p lind VAT £16.10), inclusive capacitor MA, 24V DC - 36 r.p.m. N/L 18 MA. Total length of motor and boiler ignition. Dozens of uses in the field of physics and electronics, 1 rpm Torque 101b An. reversible 1/70th h.p 110V AC gearbox 90 M/M. Max. Dia 42 M/M. Shah Length 15 M/M. Shah Dia e.g. supplying neon or argon tubes etc. £6.50 + 90p p&p (Total inc. motor Price £9.50 + f 180 6 M/M. Approx. half manufacturers price- £15.00 p&p £2.00 - total VAT £8.501 N.M.S. p&p (Total inc. VAT £12.991 inclusive of VAT £19.55. Suitable TRANSFORMER for 230-240V AC operation. Price 620 i p&p El 40 (Total inc. VAT 2.59) N.M.S. VBL4 CENTRIFUGAL BLOWER FROM STOCK AT PRICES 24V DC 200 rpm101b/in Ml. by Carter. Ex -equip. tested. £8.00+ f 1.50 p&p (Tot inc. VAT £10.93). 240V AC powerful 1 /50 h. p. 0.23A motor. E18.00 +£2.00 p&p (Total Inc. THAT DEFY COMPETITION VAT £23.00). N.M.S. 730/240V AC SYNCHRONOUS, 2 rpm. 6 rpm, 6 rev per day Any type. £4.80 r 50 h AC GEARED MOTORS C F. BLOWERS 12/24V DC Centrifugal Blower 0.4A producing 30 cu.ft. £7.50 + £1.00 p&p liotal inc VAT £6.101 DC MOTORS SMALL P&P (Total inc. VAT £9.78) N.M.S. AC CAPACITORS CHECK METER h MICROSWITCHES STROBE KITS 230/240 AC 40 amp. fully reconditioned £7.50 - £1.75 p&p (Total inc. VAT COOLING or EXTRACTOR FAN RELAYS FLASHTUBES £10.64) Chum serooth running Size 434 x43/4.11,2. Supplied REED SWITCHES CONTACTORS for 240V a.c operation. Price £4.75 a f1 p&p (Total SANGAMO WESTON TIME SOLENOIDS A.C. or D.C. SYNCHRONOUS SWITCH inc. VAT £6.621 N.M.S. Type S251 200/250 0 C 2 on 2 oh every 24 hours, 20 amps contacts with overnee PROGRAMME TIMERS MOTORS switch Dimaeter 4- - 3" Price 6.50 + £1.50 p&p e12.ó inc. VAT & popl Alsa 240V A.C. SOLENOID VALVE !-J WIDE RANGE OF XENON TUBES available with solar dia R&T Other types available from stock Designed for Air/Gas at 0.7. Water 5 psi. Inlet -outlet 3/8. Forged brass WRITE/PHONE IN YOUR ENQUIRIES N.M.S. New Manufacturers' Surplus body. Manuf. Dewraswitch Asco. PRice £5.50 + £1 p&p (£7.48 inc. R&T Reconditioned and tested VAT) N.M.S. Goods normally despatched within 7 days

Ample parking callers only. Open Saturdays space SERVICE TRADING Personal Showroom open aim CO 9 le Newport Street 57 BRIDGMAN ROAD, CHISWICK, LONDON 'I W4 5BB. Tel: 01-995 1560 Monday -Friday Tennddon WC 2H 7JJ ACCOUNT CUSTOMERS MIN. ORDER £10 Tel: 01-437 055 76

CIRCLE 18 FOR FURTHER DETAILS. ELECTRONICS C.A.D. "ANALYSER" TALKING COMPUTER TERMINAL PERFORMANCE ANALYSIS of LINEAR CIRCUITS using the BBC MODEL B AND SINCLAIR SPECTRUM 48K TDS2000 FOR PRECISION DATA INPUT MICROS

Simulates Resistors, Capacitors, Inductors, Transformers, Bipolar and Field effect Transistors and Operational Amplifiers in any circuit configuration.

Performs FREQUENCY RESPONSE ANALYSIS on Circuits with up to 30 Nodes and 100 Components, for Phase and Gain/Loss, Input Impedance and Output Impedance.

Ideal for theanalysis of ACTIVE and PASSIVE FILTERS, AUDIO, WIDEBAND and R.F. AMPLIFIERS, LINEAR INTEGRATED CIRCUITS etc, etc.

"ANALYSER" can greatly reduce or even eliminate the need to breadboard new designs.

USED BY INDUSTRIAL AND UNIVERSITY R&D DEPARTMENTS WORLD WIDE.

VERY EASY TO USE. PRICES FROM £20 PAYMENT BY ACCESS OR AMERICAN EXPRESS WELCOME... For further details write or phone NUMBER ONE SYSTEMS DEPARTMENT WW 9A CROWN STREET, ST IVES LEE488 & RS232C INTERFACES. £1611.00 HUNTINGDON TEL: 0480 61778 CAMBS. UK. PE 17 4EB. TELEX: 32339 Triangle Digital Services Ltd. 100e Wood Street. Welthametow. Landon Ell 3HX Tel: 01.520.0442 Telex 262284 (Quote REF 7751 CIRCLE 88 FOR FURTHER DETAILS. CIRCLE 74 FOR FURTHER DETAILS. 12 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com Electronic Brokers Second User Test and Measurment Equipment Division THE SOURCE OF ALL GOOD USED TEST E6WIPMENT for 492 SIGNAL SOURCES OSCILLOSCOPES TR503 Tracking Generator 26001 with 2 x 26116 Amplifiers TEKTRONIX 7000 SERIES or 496 (MLP £6,332) £4,250 HEWLETT PACKARD and 26201 7313 opt 01 25MHz Bistable TEKTRONIX TM500 & 214A Pulse Generator to 1 MHz Timebase. Storage Oscilloscope Mainframe TM5000 SERIES Double Pulse Mode 100V, A4 Size 4,9cm/µs Stored Writing Speed 00501 Digital Delay Delay to 99,999 200 watts output £950 X -Y Ranges: 50µV to 10V/cm in (MLP £4,932) £2,225 events (MLP E1,155) £775 612A UHF Signal Generator 17 Ranges 7603 100MHz Oscilloscope FG501 Low Frequency Function 450-1250MHz £1,100 Slew Speed: 150cm/second Hz to 1 MHz sine, Mainframe (MLP £2,712) £1,950 Generator, 0.001 4204A Digital Oscillator. Timebase: 0.05 to 50sec/cm in 7633 100MHz Storage Mainframe square, triangle, pulse and ramp £375 10Hz-1 MHz. 9 Ranges (MLP £7,794) £4,950 NEW CONDITION £760 (MLP £2,661) £1,400 7704A 200MHz Oscilloscope FG502 Function Generator 0.1 Hz to 26001 with 2 x 26116 Amplifers Mainframe (MLP £4,278) £2,950 11 MHz sine, square, triangle. 8011A opt 001 Pulse Generator and 26202 Power Unit instead 7904 500MHz Oscilloscope Pulse and ramp to 1.1 MHz 20MHz with Pulse Burst 16V of Timebase Mainframe (MLP £773) £565 output (MLP £1,079) £695 (MLP £2,443) £1,250 (MLP 7904A £8,709) £6,950 FG503 Function Generator 0.1 Hz to Modulator with option 004 and triangle 8403A 7000 SERIES PLUG INS 3MHz sine, square 8732B Pin Modulator 1.8-4.5GHz FLUKE 7A11 Fet 250MHz Amp (MLP £528) £400 (MLP £1,902) £1,000 887AB AC/DC Differential Voltmeter (MLP £2,669) £1,600 PG505 Pulse Generator 10Hz to 8620C Sweeper Mainframe (MLP £3,044) £1,750 7A19 600MHz S T Amplifer 100KHz pulse width 5 nsec to (MLP £3,076) £2,495 8921A DVM Wideband, autoranging (MLP £2,422) £1,600 0.5 sec (MLP £864) £450 Pli)g In 2-8.4GHz in volts or dB. to 86240B Sweeper True RMS Readout 7A26 200MHz D T Amplifier PG508 Pulse Generator 5Hz (MLP £6,152) £4,200 Bandwidth 10Hz-20Mhz pulse width 10 nsec to (MLP £1,917) £1,325 50MHz 86260A Sweeper Plug In (MLP £1,326) £695 7B53Á 0.05µS D Timebase msec (MLP £1,904) £1,250 12.4-18GHz 893A AC/DC Differential Voltmeter (MLP £1,434) £985 RG501 Ramp Generator 104 to (MLP £4,195) £3,600 £750 1Os ramp duration 10V gate out, 7B80 10nS Timebase 8640A AM/FM Signal Generator 931 B Differential Voltmeter. (MLP £1,405) £960 TTL compatible £350 0.5-512MHz TRUE RMS £1,000 7885 10nS Delay Timebase SC501 5MHz Single Channel Plug-in (MLP £7,191) £2,250 HEWLETT PACKARD (MLP £1,609) £925 Oscilloscope 10mV sensitivity, Sweeper Mainframe £2,000 427A Analogue AC/DC/Ohm Meter single series 8690B PHILIPS occupies TM500 8698B Sweeper Plug In (MLP £810) £495 (MLP £1,166) £500 PM3232 10MHz True Dual Beam compartment 0.4-110MHz £1,000 467A Power Amplifer DC -1 MHz Oscilloscope £495 SC502 15MHz Dual Channel Plug-in 8601A Sweeper £725 Oscilloscope 1 mV/div sensitivity, TEKTRONIX 100KHz-110MHz £1,950 7040A X -Y Recorder 1 V/Inch 212 Miniature 500KHz D T Battery 2Ons/div calibrated sweep MARCONI (MLP £1,882) £850 Oscilloscope (MLP £1,746) £650 Occupies two TM500 series TF2015 AM/FM 10-520MHz HEWLETT PACKARD 434 opt 01 25MHz D T Storage compartments (MLP £2,131) £900 (MLP £2,175) £1,450 MICROWAVE ACCESSORIES Oscilloscope (MLP £5,459) £2,000 SC504 80MHz Dual Channel Plug-in TF2120 Waveform Generator Sine, P382A Attenuator 12.4-18.0GHz 475 200MHz D T Oscilloscope Oscilloscope 5mV/div sensitivity, Square, Triangular and Ramp (MLP £1,100) £425 (MLP £4,104) £2,250 5ns/div calibrated sweep, true X -Y o/p Waveforms 0.0008Hz-100KHz X382A Attenuator 8.2-12.4GHz capability (MLP £2,690) £995 LOGIC ANALYSERS £750 (MLP £1,100)E425 SG502 Low Distortion Signal TF2169 Pulse Modulator 10-520MHz J752C Directional Coupler FLUKE Generator 5Hz-500KHz £600 3010A Programmable PCB Logic for use with TF2015, TF2016 and 5.85-8.2GHz (MLP £776) £525 other generators £200 J910A Termination 5.3-8.2GHz Tester (MLP £19,153) £8,000 SG504 Signal Generator for TF20028 £175 HEWLETT PACKARD 245MHz-1050MHz TF2170B Synchronizer 1615A 20MHz £3,000 £500 116920 Dual-Directional Coupler (MLP £3,197) £2,100 TF2173 Synchronizer for TF2016 2-18GHz (MLP £2,025)) £1,500 TEKTRONIX SG505 Oscillator 10Hz to 100KHz £600 Modulator 2-18GHz 7002 opt 01 Microprocessor 11720A Pulse sinewave Ultra -low distortion - 6058 Signal Generator 7-12.5GHz (MLP E2,650) £1,950 Analyser. Up to 52 Channels 0.0008% THD (MLP £696) £400 (MLP £7,144) £3,950 £850 MARCONI TG501 opt 01 Time Mark Generator CT596 (6460/1) Wattmeter SIGNAL ANALYSERS (MLP £2,213) £1,450 GENERAL EQUIPMENT 10MHz-18GHz. 0.3µW-10mW. HEWLETT PACKARD TEKTRONIX TV TEST AVO Extended to 1W with 141T + 85528 + 6555A Spectrum EQUIPMENT Model 8 (various versions) £80-£85 6534/4. 20db attenuator £1,500 Bridge 0.1% Analyser 10MHz-18GHz 380 Portable NTSC Vector/ B IRD TF1313A LCR (MLP £16,562) £12,650 £2,750 4311 Peak Power Meter (MLP £1,470) £775 Waveform/Scope Test Set £850 TEKTRONIX 521A Vectorscope £4,500 (MLP £540) £300 TF2333 MF Trans B RYANS SOUTHERN 2438 Counter/Timer DC-520MHz 491 Spectrum Analyser (MLP £908) £795 1.5GHz-12.4GHz £3,000 DISPLAYS HEWLETT PACKARD 29300 A4 Size RACAL 1.5GHz-18GHz £3,500 X -Y Ranges: 0.25mV to 10V/cm High Resolution X-Y Display Store 40S FM Taperecorder £3,950 1.5GHz-26.5GHz £4,000 1332A in 10 Ranges x 11.9cm Display Area option TEKTRONIX 1.5GHz-40GHz £4,500 9.6 Slew Speed: 70cm/second Blanking and Analog Z 1503 TDR Cable Tester 216 (TTL Timebase: 0.1 to 50sec/cm in TR502 Tracking Generator for Mod) and option 330 (covers Feet (MLP £4,931) £3,000 9 Ranges 2701 Attenuator 50n 0.79db in 7L12, 7L13, 7L14 etc. to Medical Standards) (MLP £1,637) £1,000 (MLP £6,332) £3,000 (MLP £2,190) £1,250 1 db steps (MLP E590) £295 DEC COMPUTERS ;I' Electronic Brokers Second User O1 Computer Division holds huge stocks '- of all popular DEC Processors, Disk SAVE up to 50% Drives, Peripherals and Options. Phone or write for latest catalgoue. v Electronic Brokers are Europe's largest specialists in quality Electronic Brokers Guarantee second user test equipment. Established 17 years ago, we have Unless otherwise stated, all test equipment sold by us carries a 12 pioneered the second user concept in Britain, and many overseas month warranty. When you buy from Electronic Brokers you know the territories. To support our growth we have a skilled team. This includes equipment is in 'top notch' condition. It is refurbished in our own service trained sales staff, whose role is not only to sell, but provide a helpful laboratories and checked to meet the original manufacturer's sales information service to our many customers. Backing this team is our specifications. And it's serviced by our own highly qualified technicians. own service laboratory where technicians monitor each item of All prices exclusive of VAT Carriage and packing charges extra on equipment we sell. Our maxim is service, and those who have dealt with all items unless otherwise stated. us will know that we endeavour to always live up to our reputation. A copy of our trading conditions is available on request. _ r - , ' f , `- Electronic Brokers Ltd ' L140-146 Camden Street London NVIII9PB Electronic Brokers Telephone 01-2677070 Telex 298694 CIRCLE 201 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com The Northern LOOK AHEAD! Amateur Radio WITH MONOLITH MAGNETIC TAPE HEADS VIDEO HEAD REPLACEMENT KIT Societies Association DOES YOUR VCR GIVE WASHED OUT NOISY PICTURES - IT'S PROBABLY IN NEED OF A NEW HEAD - FAST FROM OUR EX -STOCK will be holding their DELIVERIES. SAVE £££s ON REPAIR CHARGES. OUR UNIVERSAL REPLACEMENT VIDEO HEADS FIT ALL MODELS OF 23RD ANNUAL VHS OR BETAMAX VCRs. FOLLOWING OUR REPLACEMENT GUIDE AND WITH A PRACTICAL ABILITY, YOU CAN DO THE WHOLE JOB IN RADIO & ELECTRONICS YOUR OWN HOME WITH OUR HEAD REPLACEMENT KIT. EXHIBITION AND MOBILE RALLY in The Central Hall Belle Vue, Redgate Lane, Longsight, Manchester on Sunday 10th March 1985 commencing at 11.00 a.m. 10110"

Admission will be £ 1.00 to the exhibition. HT CONTAINS - NEW VIDEO HEAD, 5 CLEANING TOOLS, HEAD CLEANING FLUID, CAN OF AIR BLAST, INSPECTION MIRROR, ANTI- OAP's and Children -50p STATIC CLOTH, VHS/BETAMAX MAINTENANCE MANUAL, CROSS HEAD SCREWDRIVER, HANDLING GLOVES, MOTOR SPEED DISC, SERVICE LABEL, HEAD REPLACEMENT GUIDE. Car Park facilities (80p) will be available JHS KITS £6325, BETAMAX KIT £75.25. Prices include P&P and VAT HOW TO ORDER: PLEASE STATE CLEARLY THE MAKE AND MODEL as will be restaurant & bar. OF YOUR RECORDER. THERE ARE TWO VERSIONS OF THE VHS HEAD AND YOUR ORDER CAN BE PROCESSED FASTER IF YOU CHECK THE SIZE OF THE CENTRE HOLE OF THE HEAD WHICH WILL Contests and a raffle will take place. BE EITHER 5mm OR 15mm DIAMETER. CATALOGUE: For our full Catalogue of Replacement There will be a play area for children. Video and Audio Cassette/Reel to Reel Heads, Motors, Mechanisms, etc. Please forward 50p P&P. THE MONOLITH ELECTRONICS CO. LTD. Talk in will be on S22, SU8, 5-7 Church Street, Crewkerne, Somerset TA18 7HR, England or any other clear frequency. Telephone: Crewkerne (0460) 74321 Telex: 46306 MONLTH G

CIRCLE 9 FOR FURTHER DETAILS. CIRCLE 81 FOR FURTHER DETAILS.

COMPUTER . PRODUCTS * Fully guaranteed Performance to original specification FR01111 CARST(1 * Wide range of instruments & computer products 44I 943for latest IIII _ Ring i - stock information 99, Waldegrave Road, Teddington, Middlesex TW11 8LL. ELECTRONICS LTD. Telephone 01- 943 4477. Telex 23920 (Euhire) Used test equipment and computer specialist CIRCLE 123 FOR FURTHER DETAILS. att MITSUBISHI Z80A MICRO -CONTROLLERS 4MHz 280A CPU MG F-1400 4K EPROM - 2K supplied with MCV2.0 GaAs FETs 4K Battery backed RAM - 2K supplied MG F-1402 4 x Z80A PIO's (641/0 lines) ZBOA CTC MG F-1412 FROM STOCK Standard 100mm x 160mm Eurocard Cost effective prices (£94.04-10 off) Aspen Electronics Limited 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 UK representative for Mitsubishi Electric of the powerful Z80 family IC's. Micro -controllers are available with up to 64K RAM, 8K EPROM. RS232 etc. M.iouals include circuit diagrams and assembly language listings. No ULA's, PAL's or other funnies. Mite, phone or circle to find out more about our powerful range of Z80A micro -controllers and multi - tasking 2/3 Kildare Close, Eastcote, Ruislip software. PRICES Middlesex HA4 9UR CIJB (built 8 tested) £103.44 GNC ELECTRONICS Tel: 01-868 1188 Tlx: 8812727 Bzre board £2,.00 Little Lodge, Hopton Road, Manual (free with CUB/board) £3.50 Thelnetham, Dios, Norfolk. IP22 1 JN. Please add £1.00 for P&P plus V.A.T. Tel; Diss (0379) 898313.

CIRCLE 83 FOR FURTHER DETAILS. CIRCLE 36 FOR FURTHER DETAILS.

11 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com CRYSTALS 8086 6502 1MHz 4.50 FAMILY FAMILY 1.008MHz 2.70 8086 19.50 1.8432MHz 3.50 6502A 4.95 8088-2 22.50 2.4576MHz 2.00 6520 2.25 8216 1.75 onents 4MHz 1.25 6520A 2.45 8237A-5 23.50 co 6MHz 1.30 TEL:0379 4131 6522 3.25 8251A 6.00 HI -TECH COMPONENTS,GILRAY ROAD, DISS, NORFOLK. 8MHz 1.25 6522A 4.45 8253-5 7.50 3.6864MHz 2.00 6532 5.00 8255A-5 5.50 98304MHz 2.75 6532A 5.95 8259A 6.60 19.6608MHz 2.50 TERMS OF BUSINESS 6551 5.25 8272 35.00 INSULATION 8284A 9.50 for 80(86 46.65 * All prices exclude V.A.T. and carriage. Please add * Goods incorrectly ordered cannot be accepted DISPLACEMENT 6800 80(88 46.65 carriage to order total before adding V.A.T. replacement without our prior agreement. Due to CONNECTOR SYSTEM 82(52 15.68 high processing costs, a minimum of 15% handling FAMILY 82(54 19.04 * Carriage charges extra on all orders as follows: HEADERS OPEN - charge may be levied on any returns or cancelled 82C55A212.98 £0.75 SHROUDED OPEN STRAIGHT 6800 2.50 Components 82C59A 15.22 orders. 90' 90' PINS 6802 3.50 82(82 6.26 Disc drives £4.50 10 way 0.86 0.65 0.47 6803C 8.40 82C84A 8.94 * We will issue a full immediate refund, if requested, VISA) 14 way 1.22 0.83 0.59 6809E 6.25 16.80 * Strictly cash with order or credit card (Access or 82(88 for out of stock items. 16 way 1.34 0.92 0.65 6809P 6.25 only. 6810 1.70 full manufacturers warranty. 20 way 1.36 1.13 0.77 * All items carry 1.70 1.40 0.95 6821 1.70 Z80 * Delivery is normally from stock but please allow up 26 way 6840 3.70 FAMILY * A V.A.T. receipt will be supplied with all orders. 34 way 2.04 1.78 1.19 to 28 days. 40 way 2.28 2.07 1.37 6845 7.50 Z80ACPU 2.50 1.70 * Prices quoted are correct at the time of going to 50 way 2.70 2.54 1.67 6850 Z80ACTC 2.50 * Any query or complaint regarding an order should 6862 3.75 right to effect changes 60 way 3.20 3.02 1.96 Z8OADMA7.95 in within 7 days of receipt of the press but we reserve the 8.00 be made writing 6875 Z80AP10 2.50 notice. order. No telephone queries will be entertained. without prior SOCKETS DIP PLUGS 68800 4.30 Z80AS10-06.20 11.00 10 way 0.88 14 way 0.92 68809 Z80A510-1 7.95 68810 1.88 14 way 1.06 16 way 1.06 Z80A510-2 7.95 4021 0.56 68821 3.70 T1064 -CN 0.95 74HC253N 1.03 7415196 1.10 16 way 1.16 24 way 1.60 Z8OBCPU 5.95 DEV. FAIRCHILD LINEAR/INT. TL066-CP 0.28 74HC257N 1.03 7415197 1.10 4022 0.42 20 way 1.38 40 way 2.40 68640 6.60 Z80BCTC 5.95 FAST 4702 8.90 TL071-CP 0.28 74HC266N 0.92 741520 0.22 4023 0.23 26 way 1.66 68850 2.00 Z80BPI0 5.95 HCI-55564-5 10.66 TL072-CP 0.56 74FOOPC 0.60 74HC273N 2.24 741321 0.17 4024 0.40 way 1.94 TRANS. 68654 8.75 Z80BSI0-019.95 34 (Speech Synthesis) T1074 -CN 1.10 74F04PC 0.60 74HC27N 0.80 74L522 0.17 4025 0.16 40 way 2.08 Z80BSI0-119.95 CONNS. AM7910DC 34.88 TL081-CP 0.29 74F08PC 0.65 74HC280N 3.26 7413221 0.62 4026 0.74 50 way 2.78 Z80B510-219.95 10 way 0.86 AM7911 DC 34.88 TL082-CP 0.49 74F109PC 0.65 741-102 0.40 7415240 1.40 4027 0.52 way 3.34 Z80510-0 6.00 60 16 way 1.17 25L52518PC 3.60 T1084 -CN 1.02 74F11PC 0.52 74HC373N 2.40 7415241 0.48 4028 0.34 CARD 20 way 1.37 Z80SI0-1 6.00 3.28 TL091-CP 0.39 74F138PC 0.52 4031 0.93 25LS2521PC 7411C374N 2.40 74L5242 1.36 26 way 1.67 Z80510-2 6.00 25LS2538PC 2.72 TL092-CP 0.72 74F138PC 1.26 4033 EDGE 74HC393N 1.78 74LS243 1.36 2.40 34 way 1.87 1.30 74F139PC 1.26 4034 MEMORIES - EPROM 25LS2539PC 2.72 TL094-CN 74HC4002 0.64 74L5244 1.40 1.00 10 way 1.84 40 way 2.23 26L531PC 2.62 TL487-CP 0.59 74E151 1.26 7411(4017 1.16 7415245 1.95 4035 0.54 20 way 3.14 2532-300ns 4.95 26LS32PC 2.62 7L489-CP 0.59 74F1 53 1.26 74HC4020 1.46 7415248 0.39 4040 0.41 26 way 3.80 D -TYPE 2532-450ns 3.95 6402 6.40 TL494-CN 1.99 74F157 1.30 74HC4024 1.20 74L5249 1.16 4041 0.36 34 way 4.90 2564-300ns 6.95 SOCKETS 75107BN 0.69 TL496-CP 0.59 74E158 1.17 74HC4040 1.46 7413251 0.78 4042 0.40 40 way 5.52 2708-450ns 3.95 9way 1.47 75110AN 0.86 71507-CP 1.22 74F161 2.34 7411(4060 1.46 7415253 0.25 4043 0.41 50 way 6.68 2716-450ns 3.50 15 way 2.02 75150P 0.86 ZN450-E 6.08 74F164 1.68 741-1C4075 0.64 7415257 0.78 4044 0.43 60 way 8.06 RAIL 7.95 25 way 2.90 2716-3 75154N 1.05 ZN451-E 7.40 74F175 1.82 74HC42N 0.90 7415258 0.27 4045 2.00 4.95 37 way 2732-350ns 75159 2.30 ZN451-KIT 29.95 74E181 3.90 74HC4511 2.51 7415259 0.42 4046 0.55 D -TYPE 3.97 2732-450ns 4.45 75160AN 2.60 74E189 5.10 74HC4514 3.76 74LS26 0.30 4047 0.50 PLUGS DIP 2764-200ns 7.95 F.D. CONTROLLERS 74F190 3.20 75161AN 2.82 74HC4538 2.36 74L5261 2.60 4048 0.40 9way 1.38 JUMPERS 2764-250ns 5.15 FD1771P 30.00 74F191 3.20 75162AN 4.08 7411(4543 3.04 7415266 0.19 4049 0.50 15 way 1.85 Single Ended 2764-300ns 4.75 FD1791 15.50 74F194 1.68 75172NG 1.96 74HC51N 0.64 74LS27 0.17 4050 0.29 25 way 2.52 24' cable 27(64-250ns 10.95 FD1791-02 11.00 74F20PC 0.52 4051 - 75173N 1.44 74HC533N 2.40 74LS273 1.35 0.40 37 way 3.34 14 pin 1.73 27C64-300ns 10.45 FD1793 18.40 74F240 3.16 75174 2.82 74HC534N 2.40 74L5279 0.77 4052 0.48 16 pin 1.90 27128-250ns 19.00 FD1793-02 11.00 74E241 2.42 75175 1.96 74HC589N 1.72 74L528 0.17 4053 0.50 24 pin 2.73 27128-300ns 16.00 FD1795 25.00 74F243 2.80 75182 0.50 74HC58N 0.64 74L5283 1.00 4054 1.30 40 pin 3.96 75183 0.50 FD1797 21.00 74F244 2.96 74HC595N 1.84 7415290 0.29 4055 0.72 14.00 MEMORIES RAM 75188 0.86 WD1691 74F245 6.08 74HC597N 1.72 74LS293 0.29 4060 0.50 RIBBON CABLE 12.00 4116-150ns 1.30 75189 0.86 WD2143 74F251 1.26 74HC73N 0.84 74L530 0.22 4063 0.60 (PRICED PER FOOT) 1.20 74F253 1.26 4116-200ns 75451BP 0.22 74HC74N 0.84 74L532 0.25 4066 0.50 GREY RAINBOW 4.00 DATA CONVERTERS 74F257 1.26 4068 4164-15Ons 75452BP 0.29 74HC75N 0.92 74LS33 0.17 0.16 9 0.16 0.25 4.70 74F258 1.34 4416-200ns 754538P 0.22 ZN425E-8 3.76 74HC76N 0.64 7415365 0.33 4069 0.23 10 0.16 0.25 74F280 1.74 4532-200ns 2.45 75454BP 0.22 ZN4251-8 8.00 74HC85N 2.02 74L5366 0.33 4070 0.23 0.21 0.35 4.45 74F283 1.74 4564-15Ons 75468N 0.88 ZN426E-8 1.90 741-1C86N 0.80 7415367 0.34 4071 0.23 15 0.22 0.37 1.95 74F32PC 0.52 8118-10Ons 75491N 0.31 ZN427E-8 6.68 74HCUO4N 0.80 7415368 0.36 4072 0.23 16 0.23 0.39 25.00 74F352 1.26 81256-15Ons 75492N 0.41 ZN4271-8 12.50 74LS37 0.17 4073 0.23 20 0.28 0.48 6.00 74F353 1.26 8416-200ns AY -3-1015 3.50 ZN428E-8 5.10 TTL 74L5373 1.50 4075 0.46 25 0.34 0.60 6.40 9.70 74F373 3.16 4076 0.48 8416-LP-200ns AY -3-1270 9.40 ZN4281-8 74L500 0.20 7415374 0.52 26 0.35 0.62 6.00 4.50 1.60 74F374 3.16 4077 0.23 8417-200ns AY -3-8910 ZN429E-8 741501 0.22 7413375 0.26 34 0.45 0.80 6.40 74F379 1.83 8417-LP-200ns AV -5-3600 8.84 ZN432C1-10 20.79 74L5377 0.46 4078 0.25 40 0.52 0.92 74F381 6.62 741502 0.20 DP8304 4.50 ZN432E-10 13.00 741503 0.22 7413378- 1.22 4081 0.23 50 0.64 1.14 RAM 25.00 74F382 4.22 1.50 MEMORIES - L203 0.99 ZN433CJ-10 741504 0.20 74LS379 4082 0.25 60 0.76 1.35 74F398 3.16 *ZERO POWER ZKXB LF398 3.80 ZN434 0.98 741338 0.25 4085 0.66 74F399 2.70 741505 0.22 CABLE ASSEMBLIES LM301AN 0.30 ZN435 4.38 74L508 74LS386 0.50 4086 0.40 CMOS* 1.26 74F521 2.76 0.22 LM308AN 0.94 ZN436E 741509 0.22 74L5390 1.10 4093 0.23 IDC JUMPERS 32.00 55.00 74F533 3.16 0.75 MK48Z02B-15Ons LM308N 0.56 ZN440 74L510 0.20 74LS393 4099 0.50 SINGLE ENDED MK48Z02B-200ns 24.00 LM311 N 0.60 ZN441 46.80 74F534 3.16 741540 0.25 7413109 0.27 4502 0.55 IDC sucker MK48Z026-250ns 23.00 LM317MT 0.80 ZN447 7.80 74F537 6.02 74LS42 0.25 36' cable 741511 0.17 4507 0.47 LM317T 1.06 ZN448E 6.66 74F538 4.38 741547 0.30 10 way 1.72 7415112 0.54 4508 0.96 2.07 BIPOLAR PROMS LM319N 1.90 ZN4481 12.48 74F539 4.38 74L548 0.35 14 way 7415113 0.27 4510 0.45 LM324N 0.40 ZN449 2.72 74F64PC 0.52 74LS49 0.34 16 way 2.22 TBP1 8S030N 1.54 7415114 0.44 4511 0.50 LM337T 1.20 22.50 74F74PC 0.58 741551 0.17 20 way 3.14 TBP18SA030 1.38 ZNA1341 741512 0.25 4512 0.40 LM339 0.48 ZNA234E 9.40 74F86PC 0.77 741354 0.17 26 way 3.75 TBP24S10N 2.06 7413122 0.42 4514 1.00 LM339N 0.38 741555 0.17 34 way 3.98 TBP24541N 6.68 7415123 0.70 4515 1.84 LM348N 0.64 74L5670 2.30 40 way 4.23 TBP24581N 5.50 VOLTAGE REF. HIGH 74L5124 2.30 4516 0.45 LM350T 3.12 74L573 0.30 50 way 5.36 TBP24SA10N 1.40 ZN404 0.50 SPEED 7415125 0.49 4518 0.40 LM358N 0.60 741574 0.35 60 way 6.36 TBP245A41N 4.40 ZN423 0.98 7415126 0.29 4519 0.25 LM3900 0.68 CMOS 741575 0.28 TBP28L22N 3.10 ZN458 0.92 741513 0.17 4520 0.64 Double Ended LM393N 0.48 741576 0.17 TBP28LA22N 4.14 ZN458A 0.92 74HCOON 0.42 7415132 0.60 4521 1.32 6" cable 12'cable 18'cable LM725CN 2.90 741378 0.19 TBP285166N 19.00 ZN458B 1.12 74HC04N 0.44 7415136 0.46 4522 0.84 14 2.74 2.84 2.94 741CP 0.16 74L583 0.28 TBP28542N 4.50 ZNREF 025 1.90 74HC08N 0.42 7415138 0.55 4526 0.52 16 3.03 3.14 3.25 LM747CN 0.60 741585 0.39 TBP28546N 4.50 ZNREF 040 1.90 74HC10N 7415139 0.55 4527 0.52 24 4.18 4.36 4.55 LM748CN 0.30 0.64 74LS86 0.42 TBP28586N 5.00 ZNREF 050 1.90 74HC132N 1.28 741514 0.50 4528 0.48 40 5.89 6.18 6.47 MC1413P 0.80 74L590 0.21 TBP28SA42N 4.50 ZNREF 062 1.90 74HC137N 1.81 7415145 1.23 4532 0.68 MC1416 0.80 74L591 1.30 D L SOCKETS TBP28SA46N 4.50 10G 3.05 74HC138N 1.20 7415148 1.50 4541 0.82 MC14411 10.10 ZNREF 0.22 W/WRAP TBP28SA86N 8.62 74HC139N 0.78 741515 0.25 741592 4543 0.60 TIN GOLD MC14412 14.20 74LS93 0.21 0.36 AM27513PV,C 3.74 UHF MODULATORS 74HC151N 1.16 7415151 0.36 4553 2.00 8 pin 0.07 0.16 MC1458CP1 0.35 741595 0.77 0.20 0.75 AM27S19PC 1.92 UM1111 2.95 74HC153N 0.90 7415153 0.36 4555 0.36 14 pin 0.09 MC1495L 6.30 0.21 0.86 AM27S191DC 15.00 UM -1233 3.45 74HC157N 1.02 7415155 0.60 4556 0.44 16 pin 0.09 MC1496P 0.70 CMOS 0.22 0.96 AM275250C 15.00 74HC158N 1.02 7415156 0.77 4585 0.48 18 pin 0.15 MC1723P 0.40 Series 0.28 1.08 AM275290C 6.46 VOLTAGE REG. 74HC160N 0.90 7415157 0.50 4000 20 pin 0.19 MC3242A 6.30 ZIF SOCKETS 22 pin 0.21 0.32 1.18 AM27535DC 22.00 0.45 74HC161N 0.90 7415158 0.62 4000 0.16 MC3302P 0.48 7805 24 pin 0.24 0.42 1.28 0.45 74HC162N 1.51 7415160 0.80 4001 0.15 24 PIN 5.70 MC3340P 2.36 7812 0.26 0.46 1.50 74HC163N 1.51 7415161 0.34 4002 0.16 28 PIN 6.90 28 pin MEMORIES E2 PROM MC3357P 1.90 7815 0.45 0.66 1.70 74HC164N 0.95 0.80 4006 0.55 40 PIN 8.25 40 pin 0.29 14.95 MC3423PL 0.81 78H055C 7.50 7415162 X2804AP-300ns 74HC165N 2.24 7415163 0.80 4007 0.16 X2804AP-350ns 13.45 MC3441AP 2.90 781-112ASC 8.95 FLOPPY DISC MECHANISMS 9.95 74HC173N 1.35 7415164 1.10 4008 0.50 X2804AP-45Ons 12.75 MC3446AP 2.90 78HGASC FDD2124 Alps 5.) 40 track single sided £ 60 74HC174N 0.80 74L5165 0.61 4009 0.25 X2816AP-300ns 29.95 MC3447P 4.30 78L05 0.30 MF351 Mitsubi hi 37 0.5 megabyte 80 track 0.30 74HC175N 0.78 7415166 1.40 4010 0.25 25.00 MC3448A 3.99 78L12 single s ded El 00 X2816AP-350ns 74HC194N 1.28 7415173 1.00 4011 0.19 22.50 MC3470P 6.44 78L15 0.30 M4855 Mitsubi hi 57 2.0 megabyte 80 track X2816AP-450ns 74HC195N 1.28 7415174 0.70 4012 0.16 MC3480 7.76 78540DM 7.50 double ided £170 3.00 74HC20N 0.40 7415175 0.96 4013 0.29 MC3487 1.80 78540PC M4854 Mitsubi hi 57 1 6 megabyte (77 track 74HC237N 1.80 7415181 2.09 4014 0.40 NE555P 0.35 7905 0.45 - 8' compatible) double sided £140 74HC240N 1.38 7415190 0.98 4015 0.50 NE556CP 0.42 7912 0.45 M4853 Mitsubi hi 51 1.0 megabyte 80 track 741-1C241N 1.34 74L5191 0.75 4016 0.29 R032513 -L 9.40 7915 0.45 double sided £110 °PI 74HC242N 2.24 7415192 0.36 4017 0.40 R032513 -U 9.40 LM309K 0.95 M4851 Mitsubi hi 57 0.5 megabyte 40 track &id LM317K 2.45 74HC243N 2.24 7415193 1.10 4018 0.40 TL010-CP 0.44 double sided £100 4.95 74HC244N 1.32 7415194 0.28 4019 0.30 71061-CLP 0.28 LN323K M2896 Mitsubishi 8' 1.6 megabyte 77 track 4.50 74HC251N 1.03 7415195 0.78 4020 0.41 0379 4131 TL062-CP 0.47 LM338K double sided £310 CIRCLE 77 FOR FURTHER DETAILS. 15 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com Add 8 channels to your oscilloscope

New Thurlby OM358multiplexer £169 +VAT The new Thurlby 0M358 enables any oscilloscope to display 8 channels of information simultaneously. The 0M358 is ideally suited to analysing digital waveforms (in many cases it can be used to solve problems that would otherwise need a high v et. Y...... 191. . speed logic analyser) but unlike dedicated logic test equipment, it is equally suited to the display of analogue waveforms. The ability to simultaneously observe 8 waveforms is an invaluable aid in analysing the complex relationships

77743...8.71klen ,K male; that exist between signals in today's increasingly sophisticated equipment. Typical application areas include e e microprocessor based products, data transmission +C77'1 C,93 systems, analogue to digital converters, phase locked ewe loops, frequency dividers etc. The 0M358 is a professionally specified instrument with a 3% calibration accuracy and a bandwidth of 35MHz. Each input has an impedance of 1MQ-20pf and accepts signals up to ± 6V. A mode switch allows an 8 channel, 4 channel or single channel display, and triggering can be selected from any input.

0M358 multiplexer complete with two off BNC cables for connection to oscilloscope £197.80 tine' P + P and V.A.T.) III Tï urlb I S Full colour data sheet available from designed and built in !aritair:. Thurlby Electronics Ltd, New Road, St. Ives, Huntingdon, Cambs. PE17 4BG Tel: (0480) 63570.

CIRCLE 62 FOR FURTHER DETAILS. The world's most advanced low-cost bench multimeter! Thurlby 1905a £325 + VAT A complete high performance bench DMM 51/2 digits; 0.015% acc; 1 NV, 1mQ 1nA. Full ac and current functions as standard A sophisticated computing and logging DMM Linear scaling with offset; null/relative Percentage deviation; running average dBV, dBm general logarithmic calculations Limits comparison; min and max storage 100 reading timed data logging RS232 and IEEE -4.88 interface options Thurlby Electronics Ltd New Road, St.lves, Cambs. PE174BG IIThurlbylrP Tel: (0480) 63570 designed and built in Britain CIRCLE 63 FOR FURTHER DETAILS. Hitachi oscilloscopes the highest quality from £299 the most competitive prices + VAT

Hitachi Oscilloscopes provide the quality and performance that sou'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-134 10MHz Tube Storage V-422 40MHz Dual Trace VC-6015 10MHz Digital Storage V -650F 60MHz Dual Timebase VC -604I 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, B9I 3TB CIRCLE 64 FOR FURTHER DETAILS. 16 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com INVENTION & ELECTRONICS

by R.E. Young . British invention, B.Sc. (Eng.), F.I.E.E., innovation and M.R.Ae.S. electronics This series is designed to show that Britain with her unique technological strengths built up over the years - is as capable as ever of making contributions in these fields at the global level; and is doing so. Some thirty years ago, Great Bri- the situation will immediately devoted to higher education in tain seemed poised to leap ahead spring to mind, one of the most Britain it has been possible to see in a technological world centred outstanding being British compu- how attitudes to technology have on electronics and electronically - ter -based process and similar been reflected in the educational based systems and techniques. control. Other major examples field. Perhaps the most signifi- Much of the lead that this country are to be found in aerospace and cant instance of this is that the possessed came out of the deve- over the full range of medical Robbins Report, with its far- lopments of World War II, not- electronics. reaching recommendations, was ably from radar ' and - equally Nevertheless, it has to be first published in 1963, i.e. at the important - from parallel peace- accepted that since the late beginning of the period. time work on UK high -definition 1950s, a significant number of The Robbins Report, basically television 2. projects, potentially of world concerned with the provision of A comparable position had also standing, have not reached their graduate education in the UK, been reached with British com- target. In extreme cases they called for an unprecedented puters by this time; and this is have been abandoned; in others increase in the places available in examined in more detail in later the project time scale has become universities and polytechnics. articles. Suffice to say at this so extended and the overall cost This expansion was to be stage that the world's first so high that the further develop- achieved by literally increasing stored -program digital computer ment, which it would have been the numbers of both; the former (program and data held in the uneconomic to have carried out, objective being attained largely same store) - first operated suc- has been completely blocked. by bringing the old Colleges of cessfully in Manchester Univers- The unsuccessful project is not Advanced Technology to Uni- ity in June, 1948. by any means confined to the versity status, and the latter This series is intended to show British. involved the setting -up of 30 new that Britain - with her unique However, although the dec- polytechnics. technological strengths built up lared aim of this series is to give a The Robbins Report and its over the years - is as capable as considered account of the posi- implications have continued to ever of making contributions in tive contribution that the UK can receive attention in a number of these fields at this global level; make to technology, it is just a connections, particularly with and is, in fact, doing so. vital to safeguard these contribu- regard to the demand which This is, of course, in direct tions by indicating where "It can developed following the Report to conflict with the adverse criticism go wrong" as, for example, when reduce specialization in degree which has been voiced in recent the impression is given, falsely, courses. As recently as May 8th, years, especially with regard to of drive and impetus having been 1984 two letters in The Times Britain's alleged failure to keep lost. clearly advocated a change away up with modern technological from "our over -specialized and developments, not only in the Education - the concealed but cru- over -academic upper secondary high technology of electronics, cial factor and higher education." but also in their application to the Thus part of this first article will Possible consequences, such older, traditional industries. The consist of a short review of the as 'dilution' and inadequate key word here is developments changes that have taken place in course duration (two years pro- - most critics agree that the education in Britain over the posed for the initial undergradu- British are still a nation of inven- period in question, and which ate course) are clear; but in gen- tors, but that their record for have affected engineering policy, eral academics in the UK seem to bringing their new ideas to frui- 'engineering' being taken in its have agreed that there were tion is increasingly open to ques- widest sense. advantages in pursuing the prop- tion. With the amount of public com- osals, and that the implied "mass Exceptions to this reading of ment and debate which has been attack" principle was acceptable. ELECTRONICS & WIRELESS WORLD MARCH 1985 17

www.americanradiohistory.com INVENTION & ELECTRONICS

Distribution of UK National Inventive Capacity Electronics and electronically -based systems engineering

Individual inventor Independent small large industrial University Government team company department establishment

Initial Typically inventor often 'known' already; Usually available Probably 'mix' of staff From this and other personnel joined later by one or otherwise recruited on within the company, (at appropriate levels) Government more associates, often a highly selective may be recruited from and selected Post- Establishments; no formal arrangement basis. outside if entirely new graduate students secondment often type of project determined during initial planning.

'start-up' 'Domestic' facilities Often combination of Area and equipment Separtated areas and Probably wide-ranging development e.g. in garage laboratory and model - made available in equipment, some facilities already resources shop facilities existing buildings shared with other available departments

Project Depends on Backing, organisation Coordinate where Determine with Project control commencement establishing contacts; assumed; forward possible with other sponsors (assumed) organization brought some form of planning for at least a activities of company ratio of academic into action for demonstration year aimed at for economic use of involvement allowed coordination and essential obtaining contracts resources relative to their work liaison

Project Demands firm interest Consolidation and Subject to usual Virtual guarantee For maximum support by outside extension of range of commercial hazards, exists in academic effectiveness, assurance organisation including contracts guaranteed by form of base especially with staff, local industry contract future should be secure

Fig .1 Distribution of UK More recently they have been neering) education. There are, of ity to write clear unambiguous national inventive capacity able to cite Japan as well as the course, other ways of achieving English. In the ultimate, this abil- United States and France as pro- such education. One proposal - ity can make all the difference viding this kind of two-year already tried out quite compre- between a patent application course. hensively - is to introduce adv- being accepted or being rejected, In contrast, the outcome of the anced graduate -apprenticeship - or between success and failure in Robbins Report has been some- type schemes as a main part of bringing an invention (or any new what different for UK engineering career structures, enabling equipment for that matter) into and invention. The two major innovative ability to be recog- production, where the hand -over issues which have arisen lie in nized and built up under real -life between development and the two areas. conditions. manufacturing side must be com- `H.N.C.' In the past Higher Early education and technological plete. This aspect is examined in National Certificate, with its spe- thinking. more detail later, especially with cialist endorsements, had pro- Similar but less noticeable regard to maintaining continuity vided a route to Chartered Engi- changes have appeared over this of design during this critical, and neer status through a combina- period in conventional education often lengthy, transfer. tion of part-time study and 'real in the UK where the trend has The need for precise English job' working. This represented been to reduce the attention almost certainly becomes most an element in the technical edu- given to basic subjects ('the 3 Rs' apparent in the preparation of cation which has been described in English parlance). That the software. This need remains, in as being the envy of the world. effect of these changes should fact, until any computer -based In fact the H.N.C. - super- enter into later life - particularly scheme is completed; and as seen ficially 'down' in academic con- where engineering is concerned in the production of the 'system tent - has been seen to provide a - may seem unlikely. Neverthe- facilities statement' and in the unique form of broad technical less, analysis shows that what design and development into education which has served the can be regarded as a change in which it leads and which is conse- country well in the past. Surpris- policy has had repercussions quent upon it 3. ing though it may seem, this has extending over the whole range of It is, however, in the process of applied with special force to engi- technological thinking. 'setting to work' that one fully neering research and develop- As will be shown in this and realises how necessary it is to go ment, where much of the actual subsequent atticles, these basic back to first principles whenever innovative contribution to the subjects become, if anything, an obscure (effectively intang- 'small team' approach came from increasingly vital with progress ible) problem arises; and how H.N.C. members, particularly up the career ladder, and with the clear it becomes that these princi- where systems engineering was corresponding demands placed ples and the way of thinking that concerned. Also the H.N.C. on technical grasp. Thus, repre- goes with them have been approach provides a reference sentative examples of this spread absorbed during early education. base for broad technical (engi- can be quoted in terms of the abil- Examples which can be quoted 18 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com in this general connection include workmanship" it requires, and in the radar installation which the climate mentioned above. It appears to be working, and yet is is felt to be more than apposite to actually 'blind', and the large con- quote the example of Sir Henry trol complex where a fault on a Royce in the present context. His critical piece of instrumentation technological flexibility in moving is literally hidden by its failure to from mechanical, through elec- provide information " - and can trical, to automobile and earon- lead to a complete system break- autical engineering, combined down. with his technical insight, match Workers in this and compar- up to all the demands of 'high able fields will be well aware that technology'. in these cases the solution is The career and technological usually simple in the extreme; achievements of Sir Henry Royce but they will be equally aware that are well documented. Outstand- the process of reaching that solu- ingly he was 'there' when high tion is not only long and involved, technology, defined as advanced but is almost invariably under- engineering permeated by elec- estimated. In summarizing, it tronics, took its shape in Great has to be stated that one cannot Britain. The developments of this put staff of too high a calibre on time are seen, for example, in clearing troubles at this level and World War II, when radar became the parallel with systems R and D an integral part of aircraft opera- is almost total; while 'sub -inven- tion. tions', for instance, will be gener- In this and in a wider connec- ated as spin-off from the primary tion, the use of 'high technology'; investigations. as with R and D, is inescapable; 15,1980) can be quoted with Fig .2 Frequency output regard to the basic manufacture The inventor, the team and 'high but unfortunate in that both these transducer - Electro- of processing technology' terms fail to convey anything like "semi -conductor mechanical assembly the breadth of the fields they equipment" in the Bristol area, mounted in standard 2 in (5 While still at school, the writer cover. Also, and particularly in when it was said that "Much of cm) case was privileged to see the inven- the UK, high technology is all but their products are exported to the tor's model of a mechanical sys- synonymous with the silicon main chip -making centres in tem for removing impurities from chip, and, with this, as only hav- Japan and the US". brick clay; and made before elec- ing appeared some two years ago; 'Cluster' areas tronics had taken over. The and there is no doubt that this equivalent of a low-speed centri- view has added indirectly but This somewhat cryptic heading fuge was represented by concen- significantly to forming the critic- covers areas exemplfied by Bris- tric circles drawn on paper cover- ism of British ability to bring tol and Peterborough, where a ing a table top. From there on, ideas to fruition. number of diversified, adaptable, however, the model was a scale To give perspective, it is poss- industries are grouped together replica of the final scheme. With ible to quote an article published to produce a powerful cluster much of the operating mechan- in the first, October 1962, issue with wide-ranging technological ism made from black strip iron, of Industrial Electronics on 'Mic- facilities and experience; and including the 'signal -box' type rominiaturization in Electronics' providing that climate so neces- controls, the final assembly was a which could almost be a 1984 sary for the inventor and for inno- tribute to the friend who had built description of the chip and its vation generally. it from the inventor's design. The manufacture - "to produce Such areas can be seen to have large brick -making company for active and passive components in existed, e.g. in the Midlands and which they both worked provided a silicon block" (the word 'chip' in the North of England, for many the greater part of the favourable came later)". years; and, within the experience circumstances and environment In the light of the opening to of many, can be identified even in which are so necessary for the this series this original publica- the smaller centres of population inventor to have; and which are tion is of special significance, not in the country. All have the key set out in the 'individual inventor' least that it marks the firm esta- feature of adaptability and the column of the distribution table. blishment of 'big -system' control ability to move into new technol- In this instance, the company in the UK: the cover picture ogy which can almost be called a - providing a connected shows the assembly on site of a national characteristic. employment base and potential mainframe computer used for Instances of this have already, interest - had pioneered new process and similar control. in effect, been given, as for exam- techniques in the industry, not- There is no need to stress the ple, with the computer work in ably in electrification; and formed date - but in view of the critic- Manchester with its heritage of part of that type of diversified ism of the post -1970 period, it is the original innovative cotton engineering area which seems to worth recording that British com- (and other) industries of the favour British invention and orig- puter based control systems con- Industrial Revolution. inal thinking generally. tinue to hold their place interna- A justifiable digression here is In the present instance, the tionally. that when the new electronic and area was that of Peterborough As a more general and broad instrument industries moved into where Sir Henry Royce was an picture, it may be pointed out that the erstwhile cotton mills of the apprentice in "the (then) Great Britain had built up a major pres- North West, they found ample Northern Railway Works" 5. Here ence in this technology at the evidence of the existance of flow - he gained an insight into classical beginning of this decade. A UK line and other modern production engineering and the "painstaking newspaper report (September techniques in the buildings they ELECTRONICS & WIRELESS WORLD MARCH 1985 19

www.americanradiohistory.com INVENTION & ELECTRONICS

had taken over. chosen frequencies or be made position indicator), with the Reverting to the pure electron- continuously variable. This sug- bearing known and the amplitude ics semiconductor, processing gestion - although it demanded of the radial time base made pro- equipment made in Bristol, it is no basic changes to the original portional to radiated signal. not invidious in the present con- concept - went far to transform- Bringing in this method showed text to point out that the work ing the whole project, not least that 'kinks' did indeed exist in the carried out in this area on the with regard to the facility it gave polar diagram; and the clearance Anglo-French Concorde airliner for clear 'At -a-glance' reading 3. of that fault became a matter of is representative of the capabilit- A consequent advantage was that visual checking of the array. ies of this cluster. the speed of development was This example is of interest in The joint achievement of the increased markedly with the its own right; but is quoted with two national teams in evolving more definite - simplified - this amount of detail to show how this unique successful supersonic design criteria which came out of the experience and know-how aircraft will be used in a later arti- the change, and which applied to built up during World War II is cle to bring out the complexity of most of the sub -system modules. still relevant in today's thinking. such systems engineering. Con- That it proved possible to First of all, this testing trary to virtually all stated opin- improve project flow in this and method, with all the neatness of a ion, it will be submitted that this other ways owed much to the good invention, had been evolved project was kept under remark- coordinated team attitude, with in a small station in the national able R and D management con- its full interchange, adopted radar network. That the circum- trol, with false trail and other almost automatically by the six stances existed for this to take sources of development crisis engineers concerned. It may be place, and for the information to peaks contained. noted that their technical qualific- be made available throughout the One of the main elements in the ations were H.N.C. or the equiv- network, was a tribute to the flex- back-up potential of these areas alent; and that their experience of ible management attitude is obviously suitable skilled manufacturing methods and adopted both at immediate and at labour; and it has to be admitted techniques contributed in great upper levels, of authority. This that increasing numbers of measure to the process of finaliz- formed part of a unified national announcements of shortages of ing the product as development effort concentrated on radar, such labour in the UK represent a proceeded. typically British, with much of threat to any future expansion. In comparison with the first the coordination and organization However, it is possible to give a example, the case history for the developing almost automatically. specific example showing that second may appear mundane at It would appear that the bringing these skills are still not far below first sight in that it can be together of technological effort the surface. The frequency -out- summed up as being the clear- on this scale has not really been put transducer in the photograph ance of a fault, actually put on in seen in the UK since that time; was built earlier this year by an manufacture. The steps leading but there are grounds for sug- ex -Polytechnic student working, up to its clearance, however, can- gesting that - as with the instru- in this instance, under conditions not be dismissed in this manner, ment making quoted earlier - corresponding with those of the following as they did the long and the potential is even now not far graduate -apprentice type of involved pattern described ear- below the surface. scheme mentioned earlier. The lier; and where suspicion of trou- The other main aspect is that craftmanship who have contri- ble is more a matter of intuitive the basic methods of gathering buted much more than is usually awareness than of 'solid' detec- evidence and data generally, realised to British engineering; tion. which were developed at that and who have constituted one of In this instance, slightly high time, do not have to be redis- the country's hidden strengths. standing -wave ratios on the open covered, and are being, and will wire feeders of a multi -element continue to be, applied in the Inventive observation and analysis radar aerial array were eventually future. For instance, the gather- To complete this extremely brief traced to incorrect connection - ing and sifting of technological survey of British inventive capa- in phase - of one pair of dipoles anecdotal evidence developed in bility, two widely separated case out of a total of sixteen, arranged analysing obscure radar faults, histories will be given which in four stacks of four. With hori- have been applied to Human show how native talent for inven- zontal polarization, it will be Communications. This forms the tive observation and analysis can appreciated that it was extremely subject of a later article in this be fostered and brought into difficult to pick up the mis -con- series, and has been generously coordinated R and D. nection on the individual vertical described as a new discipline by References The first example is taken from stack feeder by visual inspection, accepted authorities. 1. CROWTHER, J.G. and the aerospace/electronics world with fifteen out of sixteén being WHIDDINGTON, R.: Science at War, with a piece of test equipment correct. His Majesty's Stationery Office, London on a calibrated measure- In the event, and bearing in 1947 centred 2. YOUNG, R.E.: Radar and Television ment display. As originally envi- mind all the possible explanations Further articles in this series are - Interchange and Spin -Off, Wireless saged, the calibration facility was of high standing -wave ratio, as follows: World, to be published. to be provided as an electronic especially when small, it was 3. YOUNG, R.E.: Control in Hazardous graticule its spaced horizon- clearly necessary to bring in some Radar and television -interchange Environments, Peter Peregrinus, with tal lines representing specified independent check method 3, and spin-off Stevenage 1982 Aerospace 4. YOUNG, R.E.: Crisis Control, measurement ordinates. At the which could be relied on to eli- R and D management and Wireless World, June and July 1982 following minate or preferably confirm one econom- first planning meeting, ics 5. NOCKOLDS, H.: The Magic of a closely on initial briefing, the of the unknowns. That the latter Name, G.T. Foulis & Co. Ltd., London. Big -system' automation and 1949 suggestion was made that the was made possible by an ingeni- telemetry 6. JEFFRIES, P.: Microminiaturization in graticule should be replaced by a ous adaptation of the radar set Vehicle instrumentation Electronics, Industrial Electronics, Vol. 1 single calibration line which could itself to display the aerial radia- Human communications no. 1 October 1962 be selected from a stepped set of tion polar diagram on the (plan The future 20 ELECTRONICS & WIRELESS WORLD MARCH 1985

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BD376 BFX85 0.32 TIP42C 0.47 013-6100H 59.00 M28-133GH 55.00 V8006GH 65.00 AC187K 0.28 8C2088 0.13 80410 0.65 BFX86 0.30 TIP47 0.85 O 13-610GM 59.00 M31-100GH 55.00 V8010A AC188 0.25 8C212 0.09 BD434 0.65 BFX88 0.25 TIP120 0.80 65.00 0.37 0.75 D13-611 GH 59.00 M31-101 GH 55.00 2BP1 9.00 AC188K BC212L 0.09 BD437 BFY50 0.21 TIP125 0.65 D13-611 GM 59.00 M31-182GR 55.00 36P1 13.50 AD142 0.79 BC212LA 0.09 BD438 0.75 BFY51 021 TIP142 175 D13-630GH 59.00 M31-182GV 53.00 4EP1 30.00 AD143 0.82 BC213 0.09 BD520 0.85 BFY52 0.25 TIP161 2.95 D14-120GH08 65.00 M31 -183W 55.00 3WP1 18.50 AD149 0.70 BC213L 0.09 BD538 0.65 8FY90 0.77 TIP2955 0.80 BD597 0.95 TIP3055 0.55 D14-150GH 75.00 M31 -184W 85.00 314/0851 AD161 0.39 8C214 0.09 BLY48 1.75 55.00 1.25 014-150GM 75.00 M31-184GH 65.00 5131.1 AD162 0.39 BC214C 0.09 80701 BR100 0.26 TIS91 0.20 9.00 D14-172GH/84 59.00 M31 -184P31 65.00 AD161/2 0.90 BC214L 0.09 BD702 1.25 BR101 0.49 TV106/2 1.50 58HP1 30.00 0.90 2N2219 0.28 D14-172GR 55.00 M31-185GH/VR 69.00 AF106 0.50 BC237B 0.09 8 707 BR103 0.55 58HP1FF 30.00 AF114 1.95 1.50 2N2905 0.40 D14-172GV 55.00 M31 -188W 69.00 58HP31 BC238 0.09 BDX32 BRC4443 1.15 30.00 D14-173GH 55.00 M31-190GH 55.00 AF121 0.60 BC239 0.12 BDY57 1.65 BT100A/02[035 2N3053 0.40 5CP1 10.00 AF124 0.65 BC251A 0.12 8E115 0.35 2N3054 0.59 014-173GM 53.00 M31-19006 55.00 6EP7/S 39.00 ilfiilE 1.79 AF125 0.35 0.15 BF119 0.65 2N3055 0.52 014.17306 55.00 M31-190LA 55.00 13BP1 13.50 8C252A 67116 1.20 0.32 0.25 0.39 2N3702 0.12 D14-181 GH/62 65.00 M31 -190W 59.00 13BP4 17.50 AF126 BC258 8E127 T119 3.15 0.20 2N3703 0.12 014-181GH/98 65.00 M31-191 G H 59.00 17DWP4 AF127 0.65 BC258A 0.39 8E154 BT120 1.85 25.00 AF139 0.40 BC284 0.30 13E158 0.22 2N3704 0.12 014-181G) 55.00 M31-191GR 59.00 32)/1085 BU105 1.95 69.00 0.30 BF180 027 0.12 014-1816M 53.00 M31-191 GV 55.00 880/898/890/89L 15.00 AF150 0.60 BC300 BU108 1.69 2N3075 AF178 BC301 0.30 13E167 0.27 2N3706 0.12 D14-181 GM50 59.00 M31 -191W 59.00 1273 39.00 -1.95 BU124 1.25 M31 -192W 59.00 AF239 0.42 BC303 028 5F173 0_22 BU125 125 2M3708 012 D14-182GH 59.00 1564 39.00 0.09 0.38 65.00 M31-195GH 59.00 1844 45.00 AU106 4.50 BC307B 9E171 BU126 1.80 2N3733 9.50 D14-182GM/98 0.10 0.26 89.00 M31-210GH 59.00 9442E1 80.00 AU107 3.50 BC327 8E178 BU204 1.55 2N3773 2.75 O 14-2008E 0.10 0.34 85.00 M31 -220W 59.00 95447GM 75.00 AU110 ..,.12 BC328 8E179 BU205 1.30 2N3792 1.35 014-200GA/50 0.11 BC337 0.10 0.29 -2000M 75.00 M31-270GY 85.00 95449GM 75.00 BC107A 8E180 BU208 1.39 2N4427 1.95' D14 BC107B BC338 0.09 BF181 0.29 D14-210GH 75.00 M31 -271P31 85.00 7709631 78.50 0.11 BU208A 1.52 2N4444 1.15 BC108 BC347A 0.13 BF182 0.29 D 14-270GH/50 75.00 M31-271 GW 65.00 0.10 8U208D 1.85 2N5294 0.42 BC108A 0.11 BC461 0.35 8E183 0.29 O 14-3/0W 110.00 M31 -271W 65.00 8U326 1.20 255296 0.48 M36 -12W 7500 TAPE HEADS BC108B 0.12 BC478 0.20 9E184 0.28 BU407 124 2N5298 0.60 D14-320GH 85.00 BC109 0.10 BC527 020 8E185 028 D14-320GH/82 85.00 M36-141 LA 75.00 MONO HEAD 1.50 BU500 2.25 2N5496 0.95 BC109B BC547 0.10 9E194 0.11 45.00 M36-141 LG 76.00 AUTO REVERSE 3.50 0.12 BU526 1.80 2SA715 0.60 D14-340GH/KM 8C109C BC548 0.10 9E195 0.11 45.00 M36 -141W 75.00 STEREO HEAD 2.95 0.12 BU80Y- 2.25 2SC495 0.80 014-340KA 8C114 0.11 BC549A 0.10 BF196 0.11 16-100014 65.00 M36-17OLG 75.00 BUY690 1.70 2SC496 0.80 D BC116A 0.15 BC550 0.14 6E197 0.11 69.00 M38 -1000R 65.00 MJ3000 1.98 2SC1096 0.80 016-100GH/65 ELECTRO-OPTICAL 8C117 BC557 0.08 9E198 0.16 65.00 M38-101 GH 65.00 0.19 MJE340 0.40 2SC1106 2.50 D16-1000H/67 9524H 25.00 8C119 0.24 BC557B 0.08 9E199 0.14 D16-100GH87A 75.00 M38-103GR 65.00 MJE520 0.48 2SC1172Y 220 9677M 22.00 8C125 0.25 BC558 0.10 8E200 0.40 016-100GH/79 69.00 M38.120W 65.00 MPSA13 0.28 2SC1173 1.15 P42318AM BC139 0.20 8CY33A 1.60 8E241 0.1E 75.00 M38-120WA es.od 19.00 MPSA92 0.30 2SC1306 1.00 D16-1000H/79A 8C140 0.31 BD115 0.30 BF245 0.30 65.00 M38-121 GR 65.00 MRF237 3.45 2SC1307 1.50 D 16 -1000H97 8C141 BD116 0.60 M38-121 GHR 65.00 0.25 8E259 0.28 MRF450A 12.50 2SC1364 0.50 D18-160GM 69.00 WIREWOUND RESISTORS 8C142 M38-121LA 65.00 0.21 BD124P 0.59 8F257 0.28 MRF453 17.50 2SC1449 0.80 021-10GH 55.00 8C143 0.24 M38-121 WA 85.00 BD131 0.42 13E258 0.28 MRF454 23.50 2SC1678 125 D21 -10G) 69.00 4 Watt 264-10K 0.20 BC147A 0.09 B0132 0.42 8F259 0.28 D21 -10L0 69.00 M38-122GW 65.00 MRF455 17.50 2SC1909 1.45 7 Watt R47 -22K 0.20 BC147B 0.09 BD133 0.40 13E271 0.28 55.00 M38-140LA 65.00 MRF475 2.50 2SC1945 2.85 DG 7-5 BC148A 0.09 80135 0.30 9E273 0.18 M38-141 LA 65.00 11 Watt 165-15K 0.25 MRF477 10.00 2SC1953 0.85 DB7.6 35.00 BC148B 0.09 80136 0.30 8E336 0.34 DB7-36 55.00 M38-142GR 65.00 OC16W 2.50 2SC1957 0.80 17 Watt 16-15K 0.30 BC149 0.09 BD137 0.32 6E337 0.29 DG7.32 45.00 M38-142LA 65.00 0C23 1.50 2SC1969 1.95 SC157 0.12 BD138 0.30 8E338 0.32 45.00 M38 -340P31 65.00 0C42 0.75 2SC2028 1.15 DG13.2 VALVE AND CRT BASES 8C158 0.09 BD139 0.32 6E355 0.37 DH 3-91 55.00 M38-341 GR 65.00 0C44 0.75 2SC2029 1.95 BC159 0.09 BDD140 0.30 8E362 0.38 DH7.91 45.00 M38 -341P31 65.00 B5D 5.50 6130 0.50 0C45 0.55 2SC2078 1.45 8C160 0.28 BD144 1.10 13E363 0.65 M38 -344P39 65.00 B7G 0.25 B14A 3.00 OC70 0.45 2SC2091 0.85 DP7.5 35.00 BC161 028 BD150C 0.29 13E371 0.25 M40 -120W 59.00 B7G SKTD 12PIN 0.55 2SC2098 2.95 DP7.6 35.00 0.25 CRT 0.95 BC170B 0.16 80159 0.85 8E394 0.19 OC71 M43-12GM/01 85.00 DC81 0.50 2SC2166 1.95 DN13.78 35.00 88G 1.50 NUVISTOR 2.95 BC171 0.09 BDi60 1.50 8F422 0.32 2SC2314 0.80 F15.101LC M43-12LG/01 65.00 R20088 1.451 49.00 08H 0.70 OCTAL 0.35 BC171A 0.10 BD166 055 BF457 0.32 2SC2371 0.96 F16-101 GM 55.00 M44-120LC 85.00 BC1718 0.10 BD179 0.72 8F458 0.38 R20106 1.45 M44-120GR 85.00 89A 0.35 SK610 35.00 250234 0.50 F16-1011.0 55.00 BC172 0.10 80182 0.70 8E459 0.36 R2322 0.58 M47-25GR/22 65.00 89A SKT 0.40 UX5 1.75 3N211 1.95 F21-130GR 55.00 BC172B 0.10 BD201 0.83 13E467 0.88 R2323 0.68 M50 -120tH 65.00 B9G UX7 1.75 3SK88 0.55 F21 -130LC 55.00 0.75 BC172C 0.10 80202 0.85 8E595 0.23 R2540 2.48 M50.120GR 65.00 0.90- F21-13106 79.00 8108 0.20 CANS 0.30 BC1738 0.10 BD203 0.78 BF597 0.25 RCA16334 BY206 0.14 N23WE 5.00 LINE OUTPUT TRANSFORMERS E H T MULTIPLIERS VARICAP TUNERS PUSH BUTTON UNITS DIODES BV208-800 0.33 N4001 0.04 100 6.35 ELC1043/05 MULLARD 8.96. BY210-800 0.33 N4003 0.04 DECCA 7.95 ITTCVC20 DECCA, ITT, CVC206WAY 7.95 ELC1043/06 MULLARD AA119 008 BV223 0.90 54004 0.05 DECCA 1700 MONO 9.95 ITT CVC30 6.35 8.65 ITT CVC57 WAY 10.19 6.96 U321 8.25 BA115 0.13 BY298-400 0.22 N4005 0.05 DECCA 1730 8.95 PHILIPS G8 550 PHILIPS 081550)6 WAY 14.49 6.91 U322 BA145 0.16 BV299-800 0.22 N4007 0.06 DECCA 2230 8.25 RANK T20A 825 7.57 BA148 0.87 BYX10 0.20 N4148 0.02 GEC 2040 8.95 THORN 3000/3500 5.80 POTENTIOMETERS QUICK BLOW FUSES BA154 0.06 BYX36-1506 0.20 N4448 0.10 GRUNDIG 1500 15.45 THORN 8500 20MM GRUNDIG 5010-6010.2222.5011-6011 13.45 THORN 9000 8.00 BA156 0.15 BYX38-6006 0.80 N5401 0.12 STANDARD VERTICAL POTS 0.12 100MA Bp each ITT CVC20 UNIVERSAL TRIPLER 5.45 BA157 0.30 BYX55-600 0.30 N5402 0.14 MIN. VERTICAL POTS 0.12 200MA - SAMP 5p each BAX13 0.04 BYX71-600 1.10 N5403 0.12 8.25 SANDARD BAX16 0.06 PHILIPS 08 8.50 BZY95C30 0.35 N5406 0.13 REPLACEMENT HORIZONTAL POTS 0.12 B81058 0.30 CS4B 4.50 N5407 0.10 PHILIPS G9 8.99 MIN. HORIZONTAL POTS 0.12 20MM ANTI SURGE FUSES BT151 0.79 CS1o8 8.45 N5408 0.10 PHILIPS G11 13.39 ELECTROLYTIC CAPACITORS CONVERGENCE PRE-SETS 0.30 BY126 0.10 0A47 0.09 ITT44 0.04 EYE 725 10.95 SLIDERS LOG 0.48 100MA - 800MA 15p each BY127 0.11 0420 0.05 177923 0.15 REIM T20A 12.40 DECCA 301400-400/350V) 2.85 SLIDERS LINEAR 0.48 -1A- 5AMP 129 each BY133 0.15 OA91 0.06 ITT2002 0.10 TANDBERGE 90' 11.15 DECCA 80/1001400/350V) 2.99 BV164 0.45 0A95 0.08 TELEFUNKEN 711A 11.15 DECCA 1700 SPARES & AIDS 8Y176 1.20 0A202 0.10 THORN 1590 9.50 (200-200-400-350V) 3.55 BY179 0.63 1521 DR 5.00 ZENER DIODES THORN 8000 9.20 GEC 2110(600/300V) 2.25 FOAM CLEANSER 0.79 PUSH PULL MAINS SWITCH BT182 0.55 IN238 5.00 THORN 9000 9.95 ITT CVC20 (200/400V) 1.80 FREEZE IT 0.92 {DECCA, GFC, RANK, THORN BZX61 0.15 THORN 9800 BY184 0.35 IN23C 5.00 Series 22.40 PHILIPS 081600/300V) 2.25, SOLDA MOP 0.64 ETC.) - 1.02 BY199 0.40 IN23ER 5.00 BZY88 Series10.10 THORN MAIN TRANSFORMER PHILIPS G9 (2200/63V) 1.19 SWITCH CLEANER 0.79 PYE IF GAIN MODULE 0.99 3000/3500 9.70 PHILIPS G11 14701250V) 2.35 WD40 1.25 ANODE CAP (275V) 0.69

22 ELECTRONICS & WIRELESS WORLD MARCH 1985

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

148196 5.50 0S1200 3.95 UL84 0.95 3A/167M 10.00 6AV6 0.75 6.16 0.65 121(8 833A 60.00 M8204 5.50 OS1202 1.10 A SELECTION FROM OUR 3.95 UU5 3.50 3A2 9.95 6AW8A 2.50 6JB6A 3.95 12SA7GT 1.00 866A 4.50 M8223 4.50 091203 4.15 STOCK OF BRANDED VALVES UU7 8.00 3A3A 3.85 6B8G 1.50 6JE6C 4.95 12SG7 4.75 872A 27.50 M8224 2.00 051205 3.95 UU8 9.00 3A4 1.10 6BA6 0.95 873 woo M8225 6JU8 2.50 12SH7 1.00 3.50 091206 1.05 UY41 3.50 3AL5 0.95 68A7 4.50 12SK7 884 5.50 A1714 18.50 ME1401 6.156C 4.95 1.00 29.50 001207 0.90 UY85 0.70 3AT2 3.35 6BA8A 3.50 12SJ7 930 9.95 A1834 7.50 EBF80 0.86 EMI 9.00 ME1402 29.50 6.17 4.15 0.60 051208 0.90 V235A/1K 3B2 3.00 6808 1.00 12SN7GT 931A 13.95 A1998 11.50 EBF83 0.85 EM4 9.00 ME1501 14.00 61(70 2.00 1.85 051209 2.00 250.00 384 7.00 6BD4 1.50 12507 1.50 954 1.00 A2087 11.50 EBF85 0.96 EM80 0.70 MH4 3.50 6K8Y/0 3.00 051210 1.50 V238A/1K 387 4.50 6806 2.50 955 1.00 A2134 14.95 EBF89 0.70 EM81 0.70 MHLD6 4.00 6KD6 5.50 12S07GT 1.50 051211 1.50 3824 10.00 613E6 0.72 958A 1.00 A2293 EBF93 0.95 EM84 1.66 295. 00 6KM8 2.50 1303 3.20 6.50 111.4 4.50 051212 3.20 6BF5 1.80 1299A 0.80 EBL1 2.50 EM85 3.95 V240C/2K 3826 24.00 1307 3.20 A2599 37.50 MS4B 5.50 OS1213 5.00 6BG6G 3.00 6KT8 2.95 1619 2.50 A2792 27.50 EBL21 2.00 EM87 2.50 MU14 1.50 225.00 3828 12.00 1309 3.20 051215 2.10 681-16 1.95 611 2.50 1625 3.00 EC52 0.76 EN32 1/241C/1K 38Z6 1.50 A2900 11.50 1.50 MZI-100 125.00 051218 5.00 6588 1.50 6L15 3.15 130E7 2.50 1826 3.00 6070 1.75 6091 1.10 195.00 304 1.00 A3042 24.00 N37 12.50 OÚ37 9.50 68.16 1.20 6119 3.95 13DR7 2.85 2050W EC80 9.50 EN92 V2464A/2K 3C23 19.00 4.50 A3283 24.00 4.50 N78 9.85 01103-12 4.95 68K4 4.00 61600 2.95 13EM7 3.50 2050 3.95 6081 7.95 315.00 3C45 24.00 AC/HL/DD 4.00 ESU150 14.95 0A2 0.85 QV05-25 1.75 6BK7A 1.95 6160010E13.95 14S7 1.00 3545 4.00 6086 1.00 ESU872 25.00 V339 3.50 3CB6 1.50 AC/THI 4.00 OA2WA 1.50 01.(06-20 29.50 68148 0.58 BLBGT 1.50 17DW4A 2.95 404A 6088 1.00 EY51 V453 12.00 10.95 ACT22 59.75 0.80 0A3 2.50 0V08-100 3CN3A 2.50 68N4 1.85 6LD20 0.80 17EW8 6090 1.10 EY91 2.35 VLS631 10.95 0.95 927 15.00 AH221 39.00 082 0.95 145.00 3056 0.95 6806 1.85 6LF6 7.50 17JZ8 4.50 6091 5.50 EY83 1.50 VP4B 4.50 1927 25.00 AH238 39.00 OB2WA 1.25 0V2-250045.00 3CX3 2.50 61307 4.50 61.18 2.50 18D3 EC92 1.75 EY84 5.96 VP133 2.00 1.80 4212E AL60 6.00 0C2 2.50 QY3-125 65.00 3CY5 1.50 6008 2.35 6106 4.95 250.00 EC93 1.50 EY86/87 0.50 VR75/30 3.00 19AU4GT 2.50 4313C ANI 14.00 0C3 1.50 0Y4-250 70.00 306 4.50 6805 0.75 6N7 2.50 4.00 0.70 6095 7.00 EY88 0.56 OD3 0Y4-400 76.00 VR101 2.00 3021A 29.50 19G3 17.00 4328D 9.00 ARP72 1.70 6807A 0.72 6N7GT 2.50 19H4 ARP34 1.25 EC97 1.10 EY91 5.50 010 4.00 VR105/30 1.50 3D22 19.50 23.95 5642 9.50 0M4 1.00 68L7GTA 3.95 6915 1.50 1985 33.50 ARP35 2.00 EC8010 12.00 EY500A 1.50 0M58 3.00 R16 12.00 VR150/30 1.15 3E22 49.50 5651 2.50 6BL8 0.65 6P25 4.00 1906 9.00 ATP4 ECC32 3.50 EY802 0.70 0M6 1.75 R17 1.50 VT52 2.50 5654 1.95 2.50 3EH7 1.95 6818 1.15 6P26 4.00 20A2 ECC33 3.50 6235 0.75 0RP43 2.50 018 2.50 VU29 4.50 10.50 5663 1.95 AX50 5.50 3EJ7 1.95 6BR5 0.70 6P28 2.00 2001 0.70 ECC35 3.60 6240 2.7.5 ORP50 3.95 019 2.50 VU39 1.50 5670 3.25 AZ11 4.50 3W4GT 2.50 6007 4.95 607 1.20 20156 3.50 ECC81 1.16 0241 2.75 ORP93 12.00 R20 1.20 W21 4.50 5672 4.50 AZ31 2.50 48551 B 115.00 6888 2.15 6Q7GT 1.20 2011 0.95 ECC81 Special 6280 0.75 P61 2.50 R1169 55.00 5687 4.50 Quality 1.95 N/77 5.00 4-65A 59.00 68R8A 2.15 6R7G 20P1 0.55 BL63 2.00 E281 0.75 P41 2.60 RG1-125 4.95 3.15 5692 3.50 W729 1.00 4687A 9.50 6857 5.50 20P3 0.80 BS450 67.00 ECC82 0.55 0290 1.50 PABC80 0.50 RG1 -240A14.50 W739 6S4A 1.30 5896 2.75 1.50 4-125A 68W4 1.50 20P4 1.95 BS810 55.00 ECC82 Philips F6064 2.95 PC86 0.75 RG3-250A 3.50 55.00 6S7 1.10 5704 3.50 X24 1.00 6BW6 5.35 20P5 BS814 55.00 1.95 FW4/800 2.95 PC88 0.75 RG3-1250A 4-250A 85.00 6SA7GT 1.35 1.15 5718 6.15 X66/X65 4.95 68W7 1.50 21LU8 CIK 19.00 ECC83 0.85 G55/1K 9.00 PC92 3.50 35.00 4832 35.00 6SC7 1.50 2.50 5725 2,50 X76M 1.95 68W8 4.00 2481 39.50 C3JA 21.00 ECC83 Brimer 4180/2M 9.00 PC97 1.10 RK2K25 82.50 4507A 1.75 6SG7 1.35 5726 1.50 XC24 1.50 68X6 0.48 1.35 25L6GT 1.75 CA 1.36- G232 Mullard PC800 1.10 RK 20A 12.00 48Z6 1.95 6SH7 5727 1.95 C1108 XC25 0.50 68X7GT 3.50 251306 1.75 54.95 ECC83 Philips 3.95 PC900 1.25 6118 4C27 25.00 6SJ7GT 1.20 5749 2.50 1.50 XFW47 1.50 61326 2.50 2901 C112G 70.00 1.95 PCC84 4C28 25.00 6SK7 1.35 19.50 5750 1.85 G240/2D 9.00 0.40 RPL16 12.00 XFW50 1.50 6827 2.95 30017 0.40 C7134 32.00 ECC84 0.50 G400/1K 14.00 PCC85 0.54 RPY13 4C86 1.95 6SK7GT 1.35 5751 2.95 2.50 XG2-6400 604 1.10 30018 1.48 C1148A 115.00 60085 0.80 GC108 17.50 PCC88 0.70 RPY43 40X2508 6SL7GT 0.85 5763 4.95 2.50 135.00 605 1.95 3065 0.95 C1149/1 130.00 60036 2.75 GC10D 17.50 PCC89 0.70 RPY82 2.50 EIMAC 49.00 6SN7GT 1.35 5814A 3.25 XG5-500 22.50 606 2.50 30FL1 1.00 01150/1 135.00 60088 0.85 17.50 PCC189 0.70 RR3-250 4C X2500 6S07 1.35 5829WA 6.50 GC10/48 15.00 XLI -5V 1.50 6C8G 1.50 30FL2 1.35 C1534 32.00 60091 2.00 GC10/4E 17.50 PCC805 0.70 RR3-1250 35.00 tested ex 6557 1.95 XL628FT 7.50 6C11 2.50 30FL12 0.95 5636 5.50 CCA 2.60' 600180 0.72 GC12/4B 17.50 PCC806 0.80 RS613 equipment 6U4GT 1.75 45.00 XNP12 2.50 6C15 2.50 30FL13 5678 7.50 CC3L 0.90 000189 0.76 GD86W 6.00 PCE82 0.80 RS685 54.95 9.50 6U8 1.15 1.10 XR1-1600A 6018 2.50 30F114 1.25 5840 3.50 CL33 2.00 ECC801 S 3.60 GDT120M 5.00 PCF80 0.86 05688 52.15 4CX250BM 6U8A 1.50 CV Nos Prices 49.50 6CA4 0.60 6V6GT 1.15 3011 0.45 5842 11.00 ECC803S 3.50 GE10 9.00 PCF82 0.00 S6F17 5.95 EIMAC 75.00 XR1-3200A 6CA7 3.50 30115 0.60 5847 10.95 on request 600804 0.80 GN4 8.00 PCF84 0.86 S6F33 6X2N 1.00 26.95 79.50 4CX250K 6C 05 3.95 30117 D63 1.20 6002000 12.00 GN10 15.00 PCF86 1.20 S11012 6X4 1.50 0.80 5879 8.50 38.00 XR1-6400A EIMAC 95.00 60136 1.95 30P4MR DA41 22.50 60E80 1.15 GR10G 4.00 PCF87 0.40 S30/2K 6X5GT 1.00 1.00 5886 13.95 12.00 99.50 4CX125C125.00 6CD6GA 4.50 30P12 1.00 DA42 17.50 ECF82 1.15 GS10C 18.50 PCF200 1.80 6X50TY 1.00 5894 39.50 5104/1K 10.00 Y503 25.00 EIMAC 1.50 30P18 DA90 0 4.50 ECF86 1.70 GS1oH 12.00 PCF201 1.80 6X8A 2.25 0.80 5899 4.50 S109/1K 15.00 Y65 8.95 4CX350A 71.50 6CH6 6.95 30P19 DA100 125.00 ECF200 1.85 GS12D 12.00 PCF800 0.40 7A6 4.50 1.00 5963 1.75 S1311 5.95 Y602 12.00 4028 75.00 6CL3 3.95 30PL1 2.50 DAF91 0.70 ECF202 1.85 GT1C 14.00 PCF801 1.36 S130P 5.95 7A7 2.00 5965 2.25 YD1100 75.00 4GS7 2.25 6CL6 3.25 30P113 0.80 DAF96 0.65 ECF801 0.85 GT1 C S/S 13.00 PCF802 0.50 SC11800 7AD7 1.75 6005 1.85 5.00 YJ1060 265.00 4GV7 2.25 B0L8A 2.00 30PL14 1.75 DC70 1.75 60E804 6.00 GTE175M 9.00 PCF805 1.25 7B7 2.50 6012 16.00 SC1'1100 8.00 Y11020 29.00 4.152 75.00 1.80 DC90 1.20 60E805 2.50 1.00 PCF806 1.00 6CM5 705 31JS6A 5.50 6021 GTR150W SC1/1200 5.00 YL1070 130.00 4JC6A 2.95 33A/158M 3.65 DCX4-1000 ECF806 10.26 GU20 35.00 PCF808 1.25 6CM7 2.95 706 2.50 6057 2.50 SC1!1300 6.00 Y11071 135.00 4X150A ' 35.00 19.50 12.00 ECH3 2.50 GU50 17.50 PCH200 1.50 5A/102D 9.50 6056 0.75 7E7 2.50 6058 3.95 DCX4-5000 SC1/2000 9.00 Y11290 65.00 35A5 4.50 ECHO 3.00 GXU1 13.50 PCL82 0.86 5A152M 9.00 60W4 6.50 787 3.50 6059 3.75 006000M 277 1.20 6CY5 1.00 35L6GT 2.00 25.00 ECH35 3.50 GXU3 24.00 PCL83 2.50 5A163K 10.00 7AU7 1.50 6060 2.25 DET16 28.50 ECH42 1.00 45.00 Z302C 12.00 6006 2.35 35W4 0.70 GXU50SS PCL84 0.75 5A170K 6.25 6062 4.50 DET18 28.50 ECH81 0.66 SP41 5.00 Z359 9.00 6DK6 1.15 7J7 5.50 35Z3 1.85 14.50 PCL85 0.80 SP42 3.00 5A -180M 9.00 7Y4 2.50 6063 2.00 0ET23 35.00 ECH83 0.78 PCL86 0.85 Z505S 15.00 6005 4.95 38HE7 4.50 GY501 1.20 SP4B 4.95 Z520M 4.00 5A -206K 10.00 808 2.50 40KD6 5.50 6064 3.25 DET24 39.00 ECH84 0.89 GY802 1.00 PCL800 0.80 6D068 2.50 6067 DET25 SS501 35.00 2521M 8.00 5AMB 2.15 8810 2.50 42 1.95 22.00 ECH2000 1.50 GZ30 1.00 PCL805 0.90 SANG 1.20 60W4 2.15 6.95 6072 4.20 571'1 1.50 27000 3.00 8BO5 1.95 47 DET29 32.00 601.80 0.80 GZ31 1.00 PD500 3.50 5AR4 2.00 6EA4 4.95 8.00 6080 8.50 D F91 0.70 EC182 STV280/40 Z749 0.60 0.86 GZ32 1.00 P0510 3.65 5AÚ4 1.50 6EA7 2.50 8F07 1.95 50A5 1.50 6080WA 8.50 DF92 0.80 EC183 2.50 11.95 Z759 19.85 1002 1.25 GZ33 4.50 PE1-100 69.00 5B8 2.50 6EA8 2.50 5005 0.95 6096 2.85 DF96 0.65 ECL84 0.74 STV280/80 ZB00U 3.00 GZ34 2.15 PEN25 6E88 1.75 100E7 2.50 50CD6G 1.15 6132 10.00 DF97 1.00 ECL85 2.00 19.95 Z803U 18.95 58.110M 10.00 0.89 U L 6EM5 10E1 0.75 50EH5 1.50 GZ34 3.95 PEN40DD 2.50 ZA1000 12.50 58-254M 14.50 2.50 6136 2.50 DH63 1.20 ECL86 0.80 SU42 4.95 10GK6 1.95 61468 GZ37 4.50 PEN45 3.00 T82.5/300 ZA1001 1.50 5B -255M 19.50 6E117 2.50 50JY6 2.95 9.95 DH77 0.90 ECL805 0.69 10P14 2.50 6157 2.50 DH79 HAA91 1.00 PEN450D 3.00 85.00 ZA1002 1.50 513-256M 9.00 6EU7 1.95 52KU 2.00 0.55 EF37A 2.00 PEN46 10P18 0.78 53CG 15.00 6158 3.20 DH149 2.00 EF39 1.10 HABC80 0.90 2.00 TB2-300 45.00 ZC1040 8.00 5B -257M 9.00 6EU8 1.75 HBC90 PFL200 0.95 101011 1.00 61SPT 4.50 6201 DK91 0.90 EF41 3.50 0.75 783ï2000 ZM1005 8.00 5B -258M 14.50 6EV7 2.95 8.45 PL21 2.50 3.95 101_012 0.85 7581 3.50 01(92 1.20 EF42 3.50 H8C91 0.80 ZM1020 8.95 5022 125-00 6205 6.95 HF93 P136 0.95 TBL-2-300 6EW8 1.50 11E3 55.00 75C1 D K96 2.50 EF5o 2.50 0.75 ZM1021 8.00 5R4G8 3.50 2.50 6211 2.50 PL38 275.00 6EW7 4.50 12A6 3.95 0135 2.50 EF55 4.96 HF94 1.50 1.50 2M1023 7.95 5R4GY 3.50 83 8.50 6267 2.25 HK90 1.06 PL81 0.72 TD1-100A 6F1 2.00 12AD6 1.50 DL63 1.00 EF71 1.50 ZM1041 14.00 574 5.95 84 3.00 6350 2.00 PL81A 0.72 25.00 6F5 4.95 12AG8 1.50 OL70 2.50 EF72 1.20 812K 3.50 ZM1082 9.00 5U4G 2.50 85A1 6.50 6360 4.50 P182 TD03-10F 6F6 2.50 12AL5 1.00 DL73 2.50 EF73 1.00 HL23DD 4.00 0.60 ZM1084 10.00 5U408 2.50 85A2 1.50 6386 14.50 HL41 PL83 0.52 35.00 6F6G 2.00 12AT6 095 DL91 1.50 EF80 0.55 3.50 ZM1177 9.00 5V4G 1.25 90AV 10.00 6545 8.50 HL42DD PL84 TD3-12 4.00 12AT7 1.15 DL92 0.95 EF83 3.50 3.50 0.78 ZM1202 55.00 5Y3GT 1.95 6F7 5.50 90C1 2.70 6550A 10.95 14190 0.70 PL88 TDD4 5.50 12AT7WA 2.50 DL93 1.10 EF85 0.50 1.00 ZM1263 4.00 524GT 0.85 6F12 1.50 90CG 13.50 6688 6.50 HL92 1.50 PL95 1.75 TP25 1.50 12AU6 1.50 0194 2.50 EF86 2.25 ZM1812 3.00 6/3012 0.70 6F13 3.00 91 AG 9.00 6870 11.50 HL133/DD 3.50 PL302 1.00 TSP4 7.00 12AU7 0.55 0196 2.50 EF86 Special 1A3 4.50 6A/203K 9.00 6F14 1.00 92AG 19.50 6887 9.50 HR2 4.00 PL345 12.50 TT11 1.50 6F17 2.75 12AV6 1.95 DLS10 13.50 Quality 3.15 1AC6 1.20 6A7 4.95 92AV 12.50 68838 9.95 HY90 1.00 PL500 1.10 TT15 34.95 6F21 2.50 12AV7 2.50 95A1 6.50 DLS16 10.00 EF89 1 6A8G 1.50 1.50 HVR2 3.00 PL504 B3GT 1.95 6973 5.95 DM70 1.95 EF91 1.15 TT2- 45.00 6AC7 2.00 6F22 0.70 12AX4GT 1.00 10801 1.50 1.95 PL508 1022 10.00 7025 2.50 DM160 2.75 EF92 2.15 JP9-7A 50.00 1.75 TT22 45.00 6AF4A 2.50 6F23 0.80 12AX7 0.65 15002 6.95 PL509 4.85 1024 14.95 12AX7WA 7027A 4.50 DY51 1.50 EF93 0.95 1(3118 85.00 TT100 57.00 6AF9 4.15 6F24 1.25 2.50 150C2 1.50 PL519 4.95 1835A 29.50 7032 2.00 DY86/87 0.85 EF94 0.85 KR6/3 45.00 6AG5 1.50 6F25 1.25 12AY7 3.95 15004 2.15 PL802 5.95 TTR-31 MR 1BC2A 2.50 7059 2.50 DY802 0.72 1.50 KT8C 7.00 6AG7 1.95 6F28 1.25 12AZ7A 1.95 155UG 25.00 EF95 PL802T 85.00 1C1 2.50 7167 3.95 EF97 0.90 KT33C 3.50 3.50 6AH6 2.50 6F32 1.25 1284A 3.50 18581 1.50 E8'.uF 25.00 PL820 TY2-125A 85.00 1C5GT 2.50 EF98 0.90 KT36 2.00 2.95 8AJ4 2.00 6F33 17.00 128A6 1.50 274A 15.00 7189 2.35 E81L 12.00 PL5557 7Y4-400 70.00 1D5 2.50 0E183 0.65 KT44 4.00 29.50 6AJ7 2.00 6FG5 1.95 120E6 1.95 307 5.00 7193 7.50 E82CC 3.50 PY32 0.80 1FDi 2.50 EF184 0.85 KT45 4.00 TY8--600W 6AK5 6FQ7 2.95 12BH7A 2.50 328A 15.00 68300 3.50 PY33 1G3GT 2.50 1.50 EF730 1.80 KT61 4.00 0.50 365,00 6AK6 2.50 6G6G 5.50 12BL6 1.75 388A 17.50 7233 7.95 E83F 5.50 PY81 1 K3GT 2.50 EF731 3.50 KT63 2.00 0.70 TYS2/250 6AL5 0.80 6GH8A 0.80 128Y7A 2.75 425A5 8.00 7239 17.50 E86C 9.50 KT66 OSRAM PY82 0.70 375.00 114 0.80 6880 EF732 3.50 6AM4 3.25 601(5 1.50 12026 4.95 4310 2.00 7247 2.95 7.95 15.00 PY83 0.70 U18-20 2.75 116 1.50 E88CC 3.50 11.500p 6AM5 6.00 601(6 1.95 12CA5 1.95 572B 35.00 7380 10.50 USA PY88 0.65 U19 11.95 1 LA6 1.00 E9OCC 7.95. EEFFg800 KT66 9.95 6AM6 1.50 6GS7 2.15 120X6 1.20 705A 8.00 7462 15.00 KT66 GEC 14.95 PY500A 1.85 U24 2.00 1N2 4.50 708A 8.00 E9OF 7.91 EF8Ó6S 12.505p 6AN5 2.85 60117 2.50 120068 3.50 7475 5.00 KT77 Gold Lion PY800 0.79 U25 0.90 1N5GT 2.50 715A E91H 4.50 EF812 0.55 6AN8A 2.65 6GW6 2.50 12DW4A 3.50 8.00 7486 75.00 EFL200 1.50 10.95 PY801 0.79 U26 0.90 1P28 25.00 6A05 715C 45.00 E92CC 3.95 1.50 6GW8 0.80 12DW7 7551 6.95 EH90 0.72 KT81 7.00 Q83-300 54.85 U37 9.00 1S2 6AQ8 2.50 725A 275.00 E99F 8.99 0.55 0.85 6H1 9.50 7558 9.45 EK90 0.72 1(788 USA 10.95 QE03-10 3.50 U41 6.95 1S5 0.70 6AR8 3.95 12E1 17.95 803 14.95 E130L 19.95 0E08-200 U50 2.00 6H3N 1.10 12E14 28.00 7586 11.00 EL32 0.95 KT88 G Lion 18.95 174 0.70 6AS5 1.50 805 39.00 E180CC 8.50 145.00 U82 3.00 6146 1.35 12GN7 3.95 7587 26.95 EL33 4.00 1(767 9.00 1U5 1.00 6AS6 2.50 807 1.60 E182CC 9.00 OF40 65.00 U191 0.70 6H6GT 1.95 12HG7 4.50 7591A 4.95 E180F EL34 2.25 KTW61 2.50 1X28 1.40 6AS7G 4.50 810 45.00 8.50 KTW62 OP25 1.00 U192 1.00 4.9 12HG7A 4.50 7609 47.00 E186F 8.50 EL34 Mullard/ 2.50 1Z2 8.95 6AT6 0.75 811A 12.95 Philips KTW63 2.00 00E03-12 8.50 U193 0.65 6J4 6 2.155 12J7GT 3.50 813 18.50 7733 5.50 E188CC 7.50 4.50 287 1.50 6AT8 1.75 KTZ63 2.50 QQE03-2027.00 U251 1.00 6AU4 6J4WA 3.15 12K5 1.00 813USA 45.00 7788 25.00 E1T 15.00 0136 1.50 00V02-6 19.50 2822 69.50 2.00 61.37 9.00 L63 1.50 U801 0.75 6AV6 0.95 6J5 2.50 12K7GT 0.60 8298 14.50 7868 3.95 E280F 19.50 001/03-10 5.50 2C21 1.00 nn EL38 4.75 L102/2K 6.95 UABC8O 0.65 8012 15 E283CC 10.00 L120/2K 12.00 OQV03-10 UAF42 1.00 2C39A 32.50 8042 e2.9 E288CC 13.50 EL41 3.50 Mullard 15.00 2C396A EL42 2.00 LB7-20 95.00 UBF8d 0.60 39.50 8102 3.95 E810F 18.50 00V03-20 UBC41 2C40 37.00 EL81 6.95 LS98 6.95 2.95 8106 2.95 E88CCSiemans 25.00 UBC81 2C42 29.50 5.95 M502A 80.00 1.50 8136 1.00 Special 5.95 00V03 -20B UBF89 0.80 2C51 0.75 CALLERS WELCOME EL84 0.75 65.00 8156 10.95 01148 1.00 32.00 UBL21 1.75 2C53 32.00 EL85 4.50 M537A 60.00 8245 107.50 E1524 6.95 M5143 155.00 OQV06-40A UC92 1.20 2CY5 1.50 * ENTRANCE ON A227 EL86 ' 0.85 á298A EA50 1.00 27.50 UCC84 0.70 2021 1.50 6.50 EL90 1.50 M8079 6.00 8417 EA76 1.95 QGV07-50 UCC85 0.80 2021W 2.50 50 YDS SOUTH OF MEOPHAM GREEN 5.95 EL91 M8082 7.50 EA79 8.00 83.50 UCF80 1.00 2E26 7.95 9001 1.50 1.95 0195 0.70 M8083 3.25 9006 OOZ03-20 1.20 2.142 93.00 0.90 EABC80 0.70 EL153 12.15 M8091 7.50 UCHY CAR PARKING AVAILABLE 18042 42.50 UCH41 2.50 21(25 24.95 10.00 EAC91 2.50 M8096 3.00 18045 EL183E 3.50 M8098 Q0Z06-40A UCH42 2.50 Open Mon-Thurs 9am-5.30pm Fridays 9am-5.00pm 10.00 EAF42 1.20 EL18P 3.50 5.50 2K25 Raytheon EAF801 2.00 M8099 5.00 69.50 UCH81 0.65 75.00 EL360 6.75 0S75.20 1.50 * 24 HOUR ANSWERPHONE SERVICE 0034 1.50 EL500 1.40 M8100 5.50 UCL82 1.75 21(26 95.00 * M8136 7.00 OS75/40 3.00 ACCESS AND BARCLAYCARD ORDERS WELCOME 6E341 3.96 EL504 1.40 UF41 1.15 3A/107B 12.00 TRERMISTORS 6091 0.85 M8137 5.50 QS92/10 $.00 MANY OTHER ITEMS AVAILABLE EL509 5.25 4.85 UF42 1,15 3A/108A 9.00 * * VAI 040 0.23 08033 2.50 M8161 6.50 OS95/10 3A/1098 11.00 EL519 5.96 00108/45 4.00 UF80 0.80 VA1056S 0.23 68041 1.95 M8162 5.50 3A/110B 12.00 UK ORDERS P&P 50p PLEASE 68081 1.50 EL802 3.65 M8163 5.50 05150/15 6.95 UF85 1.20 ADD V.A.T. AT 15% VA1104 0.70 EL821 3A/141K 11.50 VA8650 EBC90 0.80 8.50 M8190 4.50 OS150/30 1.15 UF89 2.50 0.45 EL822 3A/147J 7.50 EXPORT VA1097 68091 0.90 12.96 M8195 8.50 OS150/45 7,00 UL44 3.50 ORDERS WELCOME. CARRIAGE/POST AT COST 0.26 j

CIRCLE 39 FOR FURTHER DE'T'AILS.

ELECTRONICS & WIRELESS WORLD MARCH 1985 23

www.americanradiohistory.com TWO STAGE GASFET STRIPLINE PREAMPLIFIERS TYPE 9051 TYPE 9048 TYPE 9010 Tuned to your specified TMOS WIDEBAND LINEAR POWER AMPLIFIERS. 4W/10W/20 watts RF output. Without channels in bands IV or V tuning. Power gain 10dß. 24V. + supply TYPE 9046 100KHz. -100MHz. 4 watts £84.50+£3.50 p&p TYPE 9051 15MHz.-200MHz. 4 watts £84.50+£3.50 p&p TYPE 9171 15MHz.-200MHz. 10 watts £140.00 + £8.00 p&p TYPE 9002 Two stage Gasfet preamplifier. N.F.0.7dB. Gain 25 dB. High Ofilter £85+£2p&p TYPE 9172 As above with integral power supply unit TYPE 9004 UHF two stage Gasfet preamplifier. N.F.0.6dB. Gain 25dB. Aligned to yourspecified £200.00+£15.00 p&p frequency in the range 250-500MHz. High 0 TYPE 9174 15MHz.-200MHz. 20 watts £180.00 + £8.00 p&p filter £85+£2 p&p TYPE 9175 As above with integral mains power supply unit TYPE 9012 Gasfet preamplifier mains power supply unit £24.50 + £3 p&p £240.00+£15.00 p&p TYPE 9010 Masthead weatherproof unit £9.50 + £2 p&p

TYPE 9152 TYPE 9159

TELEVISION LINEAR POWER AMPLIFIERS. Tuned to your specified channels in bands IV or V. (or 400-900MHz). TYPE 9061 150mV. input, 10mW. output £140+£5p&p TYPE 915210m W. input. 500mW. output £ 180+£5 p&p TYPE 9159 500mW. input, 5 watts output £210+£5 p&p TYPE TYPE 111111e 9006 9035 GASFET RF PREAMPLIFIERS. Aligned to your specified frequency in the range 30-250MHz. Masthead or local use. TYPE 9157 TYPE 9006 N.F. 0.6dB. Gain 10-40dB. variable £65.00+ £2 p&p TYPE 9006FM As above. Band 1188-108MHz £65.00 + £2 p&p TYPE 9035 Mains power supply unit for above types £24.50 + £3 p&p

TYPE TYPE 8034 9155 TYPE 8034 PHASE LOCKED SIGNAL SOURCE using low frequency reference crystal. Specify in 1-600MHz. Output 10mW.+10dBm £84.50+£2 p&p TMOS RF LINEAR POWER AMPLIFIERS. Tuned to your specified frequency in the range 10- output the range 250 MHz. TYPE 9190 80 WATT COLOUR TELEVISION TRANSMITTER. 40-250 MHz. American, British or Continental system £ 1500.00 TYPE 910510 m W. input, 3 watts output £160.00 + £ 10.00 p&p TYPE 9191 10 WATT TELEVISION TRANSMITTER. UHF bands IV or V. American, TYPE 91553 watts input, 30 watts output £240.00+ £ 10.00 p&p COLOUR TYPE 9156 As above with integral mains power supply unit £320.00+ £15.00 p&p British or Continental system £ 1500.00 TYPE 9106100 mW. input, 10 watts output £180.00 + £ 10.00 p&p TYPE 9086 FM TRANSMITTER 88-108MHz. 50 watts RF output. 24V + supply. Complete mod- TYPE 915810 watts input, 80 watts output £320.00+ £ 10 p&p ular system . £480+£30 p&p TYPE 9157 As above with integral mains power supply unit £400.00+ £15 p&p TYPE 9087 As above with integral mains power supply unit . £540+£40 p&p

si RESEARCH COMMUNICATIONS LTD. 15^b P?gso. UNIT 3, DANE JOHN WORKS, GORDON ROAD, CANTERBURY, KENT CT1 3PP P-.1'5101'. TELEPHONE: CANTERBURY (0227) 456489

CIRCLE 78 FOR FURTHER DETAILS. HYTRAK 100D SHORTS LOCATOR

The HY-TRAK 100D is the most sophisticated short-circuit locator available. To locate a solder bridge on a printed circuit board (or any other electronic assembly) you merely have to select the range - super sensitive HY-TRAK Fange for shorts between voltage planes- 200M II range for power tracks etc., place the two probes across the shorted tracks and slide the probes along the track until you either obtain the highest pitch or the lowest meter reading. You now be within a few Millimetres of STOP PRESS: should r the physical short. What could be easier? Now available --=-i14 * Special Price for payment Cie Hr.TRArc1000 with order Normally £235-74 a new ultra rilirlmiei - resistance low. * PRICE HY-TRAK ! f212-17 (20m f2-20 f2) Ring Rhiannon Jones for details (04252) 77731 C.W.O. CIRCLE 22 FOR FURTHER DETAILS.

Lynwood GD1 VDUs: Intelligent Green micro controlled, METER PROBLEMS? RS232, printer port, 101 key k/b. Full Video enhancements. ONLY £149+ £15 P&P (S/H ) Burroughs MT686/7/TD710: Intelligent Green 12' VDU with 3 micros and 64K store. RS232. Programmable...Only £199, _ new or £149 S/H + £15 P&P Open Chassis Video Monitors from above VDUs £40+7.00p&p Multirail Switching PSUs from above 5v 4A 12v+24v £25 +£1.50 Data General 6012 VDU's very attractive display working RS232 with integral 73 key k/b either dumb terminal mode or page buffered Only £120.00+ £15.00 p&p Centronics 306 Line printers: Professional fast (120 cps), superb quality 80 column printer. Parallel i/f ONLY £99+ £15.00 P&P 137 Standard Ranges in a sizes variety of and stylings available Portable system with oodles of software. Twin floppy for 10-14 Osborne Executive CP/M days delivery. Other Ranges and special scales can be drives £900+£15p&p made to order. Dlablo6300alsywheel printer. OEM i/f NEW £599 + £15 P&P Full Information from: Calcomp 565 Drum Plotter, 10thou steps ONLY £450+ £10 P&P HARRIS ELECTRONICS (London) BECKENHAM PERIPHERALS LTD Phone: 01-837 7937 Callers welcome we also buy 138 GRAY'S INN ROAD, W.C.1 by appointment 01-466 5582 redundant peripherals Telex: 892301 34 Rodway Road, Bromley Kent BR1 3JL CIRCLE 37 FOR FURTHER DETAILS. CIRCLE 25 FOR FURTHER DETAILS.

24 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com FLOPPY DISCS: Floppy discs by David March David March concludes his survey of disc storage systems for microcomputers with a look at the subtleties of Tandy's TRS-DOS

The original TRS- 80 Model I sup- major benefit ensues: the direc- 80 tracks in any combina- ported up to four external 5,lin tory cannot be accessed by nor- tion. disc drives daisy -chained mal read/write commands and so a disc with minor damage together, each of single -density, is protected from inadvertent can be salvaged and the single -sided type. Later the TRS- access or corruption. Each direc- unusable tracks locked out. 80 Model III was developed with tory entry is quite generous, even the use of track 17 for up to two built-in 5;in drives allowing comprehensive file the directory is not sacro- operating in double -density, security to be implemented. sanct as the directory track single -sided mode. Subsequently Two sectors of the directory number is held as a parame- an upgrade for the Model I was track contain ancillary informa- ter in the bootstrap sector issued which incorporated many tion about the disc in general as of track 0. of the features of the Model III well as an index to the actual operating system including dou- directory entries. ble density. The first sector holds three Both operating systems, separate sets of information. TRS-DOS directory details: Gat Sector known as TRS-DOS, provide First, a bit map indicating which Field Bytes Field name Comments granules are in use, known as the many facilities beyond straight 1 0-95 Granule allocation table One bit per granule forward file handling. Overlays granule allocation table (Gat). 2 96-191 Track lockout table 255 = track locked out are used extensively, making a Second, a map indicating any 3 192 Disc size Number of usable resident system disc essential; faulty tracks. Both tables use one tracks but in single -drive systems, there byte per track and are sized to 4 193-205 - Not used is the drawback that space for allow up to 96 tracks. Lastly, the 5 206,207 Disc password Encoded remainder of the sector contains 6 208-215 Disc name in Ascii padded with user files is considerably spaces reduced. the disc name and password, creation date and an auto start-up 7 216-223 Creation date in Ascii mm/dd/yy The TRS-80 Model II was a 8 224-255 Auto command Start-up option much more expensive business command. computer using 8in drives. The second sector contains an to entries in TRS-DOS directory details: directory entries On start-up the Model I loads index the directory and executes a bootstrap program the remaining sectors of the 1 0(0-2) Access control ranging from 0 = from track 0, sector 0. This track track. Known as the hash index unrestricted to 7 = no access is always recorded in single -dens- table (Hit), this uses one byte per 2 0(3) File visibility 0 = visible ity and so allows the directory entry. The value of each upgraded 1 invisible byte is derived from the file name = Model I to run either operating 3 0(4) Allocation 0 = directory entry by algo- system. The bootstrap loads in plus extension a hashing available rithm whilst its position in the Hit further TRS-DOS programs 1 = directory entry which remain in memory and pro- defines the sector and slot within allocated vide the core of the operating sys- sector where the corresponding 4 0(5) - Reserved tem. directory entry may be found. 5 0(6) File type 0 = user file The cost of these two sectors is 1 = system file Directory structure justified by several benefits: 6 0(7) Entry type 0 = primary entry (a) any granule can be allocated to 1 = overflow entry The directory occupies the whole any file 7 1(0-3) Primary entry number Backwards pointer to - primary entry. For of track 17. This track was redundant space in a file is 8 1(4-7) Primary entry sector overflow entries. chosen because it is half -way limited to less than one gra- across a 35 track disc and so mini- nule. 9 2 - Reserved mises head movement when files can be freely extended 10 3 EOFB Position of end of file TRS-DOS accesses the directory. or reduced in size at any byte in last sector This is very important because time. 11 4 Record length in bytes (0 = 256) even system files are accessed via by allocating different files 12 5-12 File name in Ascii padded with the directory. to separate areas of the spaces in Ascii padded with The allocation of a whole track disc, any extension will 13 13-15 File extension spaces to the directory seems at first (probably) be achieved in 14 16,17 Update password Encoded it pro- sight extravagant but does physically adjacent sectors 15 18,19 Access password Encoded vide two significant advantages. and so will keep access time 16 20,21 EOFS End of file sector. The f.d.c. used in the Model I short. i.e. length of file in supports at least two distinct syn- (b)the characteristics of a disc are sectors chronizing patterns for data fields. recorded on the disc itself - 17 22-31 Gaps 1-5 Granule assignment By applying one pattern exclus- thus TRS-DOS can handle pairs ively to the directory track a mixed drives of 35, 40 and ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com FLOPPY DISCS:

File name = TARDIS TRS-DOS directory details: Hit sector EVENTS File Extension = BAS 1 0-127 Hash index table Whole sector used for Access control =EXECUTE 64 entries in single Update password =PRIVATE February 26 density TRS-DOS of Access password = PUBLIC Electromagnetic aspects 2 128-207 - Not used optical devices; IEE 3 208-255 System file table Only in double density The normal user will be privy to Colloquium. IEE, Savoy Place, TRS-DOS all particulars except the update London WC2. Tel: 01-240 1871 password. The only valid refer- Ext. 269. 28 (c) within the limits of the hashing ence by this user will be February 26 to H.f. communication systems algorithm, search time for a RUN "TARDIS/BAS.PUBLIC" and techniques; IEE (and particular directory entry is Any attempt to access the file others) Conference at Savoy minimised Place, as above. - for reading, writing, loading or unallocated file names will March 4 be detected by a single whatever is inhibited unless the Future communications search of the Hit. update password is quoted. In the satellites; IEE lecture. Details allocated file entries will be above example the access pas- as above. accessed directly via the sword could equally well have March 6 Hit. been blank, making the whole Software reliability; security mechanism invisible to IEE Colloquium, Details as above. March 6 System files the normal user. The user simply enters Cellular mobile radio - Splitting for growth? IEE Lecture. In single -density TRS-DOS, the RUN "TARDIS/BAS" Details as above. system files (limited to 16) used March 7 In double -density TRS-DOS, the reserved file extension/SYS Design = Quality; IEE/Design the system monitors the running and occupy the first two slots in Council Colloquium. Savoy Place. of protected wipes each of the remaining directory programs and Details as above. the on sectors. This limits the number of memory clear normal or To measure is to know. IEE abnormal end of the program. Lecture. Details as above. user files to 48 but enables the Each granule assignment pair March 10 Further reading same access mechanism to be can one of Components Fair used for all files. take three meanings: (a) first byte less than 254 (this Pontefract Amateur Radio An introduction to microcomputers In double-density TRS-DOS, a byte is the track number Society vol. 3: Some Real Support Devices, separate system file table holds Centre, and the next byte defines Carleton Community by Jerry Kane and Adam Obsorne, abbreviated file location informa- Pontefract. the position within the track Osborne Associates Incorporated. time March 11 tion. This minimises access and length of the segment); since no searching is needed, Vision Systems in robotic Computer Peripherals for minicompu- (b)first byte 254 (this indi- protects system files from unau- = and industrial control; IEE ters, microprocessors and personal cates that the second byte Colloquium. Details as above. thorised access and allows up to computers, by Louis Hohenstein, holds a pointer to an over- March 12 128 user files. Each system file McGraw -Hill -Book Company. flow entry); Radiological protection entry occupies two bytes and (c) first byte = 255 (this is a aspects of microwave Data sheet on FD1771-01 floppy disc stores file position and length. flag to indicate that the end radiation; IEE lecture. Details as formatter -controller, Western Digital In double density, fields 7-9 of above. Corporation. of the file has been March 12 to 14 each primary entry contain the reached). creation date of the file. This is Scottish Computer Show Data sheet on SAB179x floppy disc held in binary with the month in As a Gap holds only the starting and Conference; Anderston formatter -controller family, Siemens position and length of a segment Exhibition Centre, Edinburgh. Aktiengesellschaft. byte 1 and the year in byte 2. of a file, additional Gaps are Cahners Exhibitions, Tel: 01-891 needed whenever 5051 Data sheet on WD 1691 floppy support File protection the storage March 14 logic, Western Digital Corporation. ceases to be contiguous. Up to ICs above 1GHz; IEE four separate segments can be Colloquium. Details as above. Data sheet on WD2143-01 four phase Fields 1, 14 and 15 provide a high addressed via the primary entry March 14 clock generator, Western Digital Cor- measure of security for files but (the fifth Gap is needed to indic- Engineering of the human poration. their use is entirely optional. ate the end of the file). brain; IEE 76th Kelvin Lectuure. Security is invoked in the first For any file which is segmented Details as above. BBC disc system user guide, Acorn instance by quoting a password more, an overflow entry is March 18 to 21 Computers Ltd, Cambridge. (up to 8 characters) when a file is created. In this case Gap5 is used Telecommunication IEE (and others) created. Subsequent access will to transmission; The CP/M handbook (with MP/M), point to the overflow entry and international conference at Savoy by Rodnay Zaks, Sybex Corporation. be available only if the password subsequent file segments are Place. Details as above. is correctly appended to the file addressed via the Gaps in the March 20 TRS-DOS & Disk Basic Reference name. overflow entry. This can be car- Connectors 85 Manual, Tandy Corporation. The introduction of a second ried on indefinitely, but each Symposium and Exhibition. Post password allows separation of the overflow entry reduces by one the House Hotel, Leicester. Details TRS-80 Model I double -density disk updating and access security faci- maximum number of user files from Robert Allen. Tel: 0789 system owner's manual, Tandy Cor- lities. The update password available. 204116. poration. allows complete freedom to load, Access to multi -segment files March 24 to 27 VIDTEL 85, Video and tv run, modify, rename or even is slow of Microsoft Basic decoded and other because repeated refer- techniques exhibition. NEC mysteries, IJG Computer Services. delete the file. Operations avail- ences to the directory. The only Birmingham. Details from NEC. able via the access password are way to coalesce such a file is by Tel: 021 780 4141. Ext 710 TRS-DOS 2.3 decoded and other limited by the value of field 1 copying it to a fresh disc since the March 26 to 28 mysteries, 11G Computer Services. (access control). For example, physical position of storage areas Interconnection consider a Basic program file hav- on the disc is not available via Technology; Exhibition, Super Utility Plus user's manual, ing the following particulars TRS-DOS. Olympia, London. Breeze/QSD Incorporated. - 26 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com NEW NEW NEW NEW NEW NEW NEW NEW FIBRE -OPTICS EDUCATOR

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www.americanradiohistory.com 01-208 1177 TECHNOMATIC LTD 01-208 1177 BBC Micro Computer System DISC DRIVES These drives, fitted with high quality JAPANESE mechanisms are supplied in attractive steel BBC Computer & Econet Referral Centre cases painted in BBC colour. The drives are fully Shuggart A4000 compatible. All dual drives are supplied with integral power supply whilst singles are supplied with or without power supply. BBC Computers: All drives come complete with data & power cables, manual and BBC formatting disc.

Model B: £348 (a) B+DFS: £400 (a) 1 X100K (250KDD unformatted) 40TSS TS55A TEAC £100 (a) Model B+NFS: £389 (a) B+NFS+DFS £450 (a) 1 X400K (1 MbDD unformatted) 80TDS TS55F TEAC 40/80 £145 (a) 2X100K (.5MbDD unformatted) 4OTSS TD55A TEAC £250 (a) ACORN 10 Mbyte Hard Disc £1300 (a) 2X400 (2MbDD unformatted) 8OTDS TD55F Mitsubishi 40/80 £360 (a) ACORN 2nd Processors: 6502: £175 (a) Z80: £352 (a) CS100 TEC with psu £125 (a) 40/80T Switch Module £30 (c) CS200 TEC with psu TORCH UNICORN: Z80 Card: £275 (a) Z80 Disc Pack: £650 (a) £165 (a) 3in. Hitachi 100K 40T £105 (b) CS400 MITS with psu £195 (a) 1X200K 40TDS £115 (a) UNICOMM Communications Package: £159 (b) 20 Mbyte Hard Disc+400K Floppy: £1950 (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 specifications Data Recording Products 3M and pricing please send for our leaflet. 3M FLOPPY DISCS PRINTERS Industry Standard floppy discs with a lifetime guarantee Discs in packs of 10 EPSON: RX8OFT £225 (a); FX80 £315 (a) 40 Track SS DD £15 (c) 40 Track DS DD £18 (c) FX100 £435 (a); RX100 £345 (a) RX8OT £215 (a) 80 Track SS DD £22 (c) 80 Track DS DD £24 (c) KAGA TAXAN: KP810 £255 (a); KP910 £359 (a) BROTHER: HR15 £340 (a); DRIVE ACCESSORIES FLOPPICLENE Disc Head Cleaning Kit with 28 disposable cleaning discs ensures continued JUKI 6100 £340 (a). optimum performance of the drives. £14.50 (c)

Single Disc Cable £6 (d) Dual Disc Cable £8.50 ACCESSORIES (d) 10 Disc Library Case £1.80 (d) 30 Disc Storage Box £6 (c) EPSON Serial Interface: 8143 £28 (b); 8148 with 2K buffer £57 (b). 30/40 Disc Lockable Box £14 (c) 100 Disc Lockable Box £19 (c) 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/FX1 00 £10 (d). JUKI: Serial Interface £65 (c); Tractor Attach, £99 (a); Sheet Feeder £199 (a); Ribbon £2.50 (a) MONITORS BROTHER HR15: Sheet Feeder £199; Ribbons - Carbonor Nylon £4.50; Multistrike £5.50 (d); MICROVITEC 141n. RGB 2000 Sheets Fanfold with extra fine pert. 9.5in. -£13.50;14.5in. £18.50 (b). 1431 Std Res £165 (a); 1431 Ap std Res PAL/Audio £210 (a); BBC Parallel Lead £8; Serial Lead £7 (d). 1451 Med Res £280 (a); 1441 Hi Res £399 (a); 2031 20in. Std Res £260 (a); Plinth for 14in. Monitors £8.50. Microvitec Monitors with TTL/Linear Inputs also available. BT Approved Modems KAGA TAXAN 121n. RGB MIRACLE WS2000: Vision II Hi Res £240 (a); The ultimate world standard modem covering all common Vision Ill Super Hi Res £340 (a) BELL and CCITT standards up to 1200 Baud. Allows communi- SOFTY II Green Screens; KAGA 12G £99 (a); SANYO DM811 112CX £90 (a); cation with virtually any computer system in the workd, The Swivel Stand for Kaga Green £21 (c) optional AUTO DIAL and AUTO ANSWER boards enhance the This low cost intelligent BBC Leads: KAGA RGB £5 Microvitec £3.50; Monochrome £3.50 (d) eprom programmer can considerable facilities already provided on the modem. Mains SANYO CD 3125 NB 14in. RGB Std Res £179 (a) powered.'£12e Auto Dial Board/Auto Answer Board £30 (d) program 2716, 2516, each. Software lead £4.50 2532, 2732, and with an TELEMOD2: adaptor, 2564 and 2764. UV ERASERS Complies with CCITT V23 1200/75 Duplex and 1200/1200 half Displays 512 byte page on PRINTER BUFFER Duplex standards that allow communications with VIEWDATA TV - has a serial and par- UV1T Eraser with built-in timer and mains indicator. This printer sharer/butter provides a simple way to allel I/O routines. Can be Built-in safety interlock to avoid accidental exposure upgrade a multiple computer system by providing services like PRESTEL, MOCRONET etc as well as user to greater used as an emulator, cas- to the harmful UV rays. utilisation of available resources. The buffer user communications. Mains powered. £62(b) otters a storage of 64K. Data from three computers tt can handle up to 5 eproms at atime with an average BUZZ BOX: sette interface. can be loaded into the butter which will continue erasing time of about 20 mins. £59 + p&p. This pocket sized modem complies with V21 300/300 Baud Softy II £195.00(b) £2 accepting data until it is full. The butter will automati- and provides and ideal solution for communications between Adaptor for 2764/ UV1 as above but without the timer. £47 + £2 p&p. cally switch from one computer to next as soon as For Industrial Users, we offer ÚV140 & users, with main frame computers and bulletin boards at a very 2564 £25.00 UV141 era- that computer has dumped all its data. The computer serswith handling then is available for other uses. LED bargraph indi- economic cost. Battery or mains operated. £52 (c) Mains capacity of 14 eproms. UV141 has a built in timer. Both offer full built in safety features cates memory usage. Simple push button control Adaptor £8 (d) provides. REPEAT, PAUSE and RESET functions. UV14O £61, ÚV141 £79, p&p £2.50. BBC to Modem data lead £7 Integral power supply. £245 (a). Cable set £30. ATTENTION All prices in this double page advertisment are CONNECTOR SYSTEMS subject to change without notice. AMPHENOL TELEPHONE I.D. CONNECTORS EDGE ALL PRICES EXCLUDE VAT CONNECTORS CONNECTORS Please add carriage 50o unless (SDerrdblock Type) 36 way plug Centronics No of F eader Recap- Edge CONNECTORS (solder 500p (IDC) 475p 4 -way plug 110p indicated as follows: ways Plug acle Conn 36 way skt Centronics 6 -way plug 180p 10 90p asp 01 0.156" (solder) 550p (IDC) 500p lal £8 (bl £2.50 (cl £1.50 (d) £1.00 20 145p 125p 1959 6 -way n ang.skt 160p 2 - 6 -way (commodore) - 300p 24 way plug IEEE (solder) 26 175p 1509 240p 10 150p Flexible cable 2.< -way - 475p (IDC) 475p ACORN IEEE INTERFACE 34 200p 160p 320p 2 x 12 -way Ivic 20) 350p 4 -way 50p/m 40 220p 190p 340p 24 way skt IEEE (solder) A full implementation of the IEEE -488 standard, pro- 2 x 18 -way - 140p 6 -way 72p/m 50 235p 200p 390p 2 x 23 -way IZX811 175p 220p 500p (IDC) 500p viding computer control of compatible scientific & 2 x 25 -way 225p 220p PCB Mtg Skt Ang Pin technical equipment, at a lower price than other sys- 2 x 2e -way (Spectrum) 200p - 24 way 700p 36 way 750p RIBBON CABLE 2 x tems. Typical applications are in experimental work D CONNECTORS 36 -way 250p - )grey/metrel 1 x 43 -way 260p No of Ways - 10-way 40p 34 -way 160p in academic and industrial laboratories. The inter- 2 x 22 -way 190p GENDER CHANGERS 9 15 25 37 - 16-way Bop 40 -way 180p 2 x 43 -way 395p 25 way D type face can support a network of upto 14 other compati- 20 -way MALE: 1 x 77 way 400p 500p 85p 50 -way 200p ble devices, and would typically link several items of 2 x 50-way(S100conni 600p 26 -way 120p 64 -way 280p Ang Pins 120 180 230 350 - Male to Male £10 test equipment allowing them to run with the opti- Solder 60 85 125 170 Male to Female £10 DIL HEADERS mum of efficiency. The IEEE Filing System ROM is IDC 175 275 325 - Female to Female £10 supplied £282. FEMALE: EURO CONNECTORS Solder IDC St Pin 100 140 210 380 14 pin 40p 100p Ang Pins 160 210 275 440 DIN 41612 RS 232 JUMPERS 16 pin 50p 110p 2 x 32 way St Pin 230p 275p INDUSTRIAL PROGRAMMER Solder 90 130 195 290 (25 way D) 18 pin 60p - 2 x 32 way Ang Pin 275p 320p 24" Single end Male £5.00 EP8000. IDC 195 325 375 20 pin 75p - Hood 90 95 100 120 3 x 32 way St Pin 260p 300p 24" Single end Female £5.25 St 24 pin 100p 150p This CPU controlled Emulator Programmer is a pow- Screw 130 150 175 3 x 32 way Ang Pin 375p 400p 24" Female Female £10.00 - IDC Skt A+ B 275p 24" Male Male f9.50 28 pin 200p - erful tool for both Eprom programming and develop- Lock 24" Male Female £9.50 ment work. EP8000 can emulate and program all IDC Skt A+C 350p 40 pin 200p 225p eproms up to 8KX8 bytes, can be used as stand TEXTOOL ZIF For 2 x 32 way please specify DIL SWITCHES MISC CONNS (A B, C). alone unit for editing and duplicating EPROMS, as a SOCKETS 24 -pin 25.75 spacing + A+ 4 -way 90p 6 -way 105p 21 pin Scan Connector 200p slave programmer or as an eprom emulator £695(a) 28 -pin £8.00 40 -pin 29.75 8 -way 120p 10 -way 150p 8 pin Video Connector 200p

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28 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com 74 LS " 0 SERIES 74273 2.00 745571 3.00 4004 74LS273 1.25 0.80 74276 1.40 745573 5.00 4005 0.90 LINEAR ICs COMPUTER COMPONENTS 7400 0.30 7418279 0.70 4096 74278 1.70 0.90 EPROMs KEYBOARD 7401 0.30 7419280 1.90 4097 2.70 907581 15.00 15711 1.00 147310 1.50 CPU 8287 4.25 MC14411 9.00 74279 0.90 74C SERIFS 0000809 11.90 75/841801 4.00 7402 0.30 7415283 0.80 4098 0.75 19723 0.10 1802CE 6.50 82880 11.00 MC14412 7.50 ENCODE Rs 74283 1.05 4099 924791001. 25.00 197245CN 3.00 184231 1.30 7403 0.30 7419290 0.80 74000 0.90 2650A 10.50 8755A 16.00 2518+5V 3.50 75107 0.90 74742 3.20 0.70 4501 0.38 9N103 1.00 191733 0.65 100800 0.80 ÁY52376 11.50 A61.5050 1.00 78Á8t0 0.60 6502 3.50 TMS9903 25.00 2516-35 5.50 75108 0.90 7404 0.36 74290 0.90 7415292 9.00 74004 0.50/ 4502 0.56 L24741 0.15 AY53600 7.50 9631270 7.50 LM747 0.70 78Á820 0.80 65002 12.00 TMS9911 2532 4.50 75109 1.20 7405 0.30 7415293 0.80 4069 4503 0.36 18.00 740922 6.50 74293 0.90 40-31360 350 124148 0.30 75482044 0.75 7406 7418295 1.40 4504 0.05 65024 5.50 TMS9911 14.00 2532 5.50 75110 0.90 0.40 74298 1.80 74008 0.70 403.2410 191011 4.90 T8Á920 1.00 740923 8.50 4505 3.90 4.00 6502B 8.00 Z80P10 2.60 256< 6.50 75112 1.60 7407 0.40 74351 7415297 9.00 74010 0.70 48.32412 5.00 061014 1.50 T8Á950 2.25 2.00 4506 0.10 6800 2.50 2708 3.00 75113 1.20 BAUD RATE 7408 0.30 7415298 1.00 74014 0.50/ 4507 0.38 CA30194. 1.00 191601 3.00 TC9109 5.00 Z80APIO 2.75 743654 0.80 71.4210 6802 3.00 2716+15V 3.50 GENERATORS 7409 0.30 7415299 2.20 40106 4584 4508 1.20 CÁ30289 1.10 191830 250 3.50 Z80CTC 2.60 75114 1.40 743664 0.80 CA3046 0.70 151871 3.00 71.9220 3.50 6809 8.50 7419321 4510 0.55 Z80ACTC 2.75 2716-35 5.50 75115 1.40 7409 0.30 74367A 3.70 74C20 0.70 C43059 325 191872 3.00 TCA270 3.50 MC14417 7.50 0.80 4511 0.65 6809E 12.00 Z80DART 8,50 2732 4.50 75121 1.40 7410 0.30 74193226 3.90 74032 1.00 4512 CA3060 3.50 151806 6.00 704940 1.75 COM8116 6.50 74368A 0.70 0.55 68809 12.00 2732A-2 7.00 75122 1.40 7411 0.30 7418323 3.00 74042 1.50 4513 1.50 CA3080E 0.70 191889 4.40 7041004* 5.00 280ADART7.00 47028 7.50 74376 1.60 7001010 68809E 16.00 27324-30 6.00 7412 0.30 7419324 3.20 74C48 1.50 4514 1.10 CA3086 060 192917 300 225 Z8ODMA 7.00 75150P 1.20 74390 1.10 7041022 4.50 UAR15 4515 1.10 CA3089E 210 103202 0.75 68000-1836.00 TMS4500 14.00 27326-35 15.00 75154 1.20 7413 0.50 7415348 2.00 74C73 1.00 1613900 0.80 1041024 110 74393 1.20 4518 0.56 CA0090h3 3.75 8035 3.50 2764-25 4.90 75159 2.20 7414 0.70 7415352 1.20 74C74 1.20 003130E 0.00 193909 1.00 10411705 3.00 13409901 5.00 AY31015P 3.00 74490 1.40 4517 2.20 8039 4.20 27256-30 54.00 75160 5.00 7416 0.36 7415353 1.20 74C76 1.00 4518 0.44 CA31307 1.30 153911 1.40 7042002 335 TMS9902 5.00 AY51013P 3.00 7042003 80804 4.20 27256-25 7417 0.40 7415356 2.10 74C53 2.00 4519 032 043140E 0.45 1613914 3.50 1.10 Z80ADMA'7.50 60.00 75161 3.50 COM8017 3.00 7415 SERIES G31407 1.00 7042004 2.40 8085A 3.00 4520 0.80 103915 3.40 Z8OASIO 7.00 27C64-25 1490 75162 4.00 IM6402 7420 0.30 7410363 1.80 74085 2.25 CÁ3148 2.25 L53916 3.40 1042008 320 3.60 741500 0.24 4521 1.15 8086 22.00 27128-2512.00 75172 3.00 TR1602 7421 0.60 7415364 1.80 74C060.50/40/ 4522 090 G13100E 0.90 1513600 1.50 1042020 3.20 3.00 74LS01 8088 17.50 MEMORIES 27128-3011.50 75182 0.90 7422 0.36 0.24 7415385 0.50 70 4507 4528 0.70 CA3181E 1.60 9515131 2.30 10412030 110 7042541 8741 16.00 MODULATORS 7423 741902 0.24 7415366 0.50 74C90 1.90 4527 0.00 CA3162E 4.40 0515161 4.50 4.00 2016-1504.00 27256-25 36.00 75188 0.60 0.36 7192591 4.00 8748 18.00 741003 0.24 4528 0.65 CA3159E 2.70 903712 2.00 2101 4.00 TMS2716 5.00 75189 0.80 7425 0.40 7415367 0.52 74093 1.50 003240E 1.50 583130 4.00 1092593 5.00 6MHZ 3.75 4529 1.00 TMS1601 12.00 75365 1.50 7426 0.40 741504 0.24 7415368 0.50 74095 1.60 C03280G 2.70 9010t0P 1.50 70*2653 7.00 2102 2.50 COT 6MHZ 4.50 0531 075 TMS9980 12.00 75450 7427 0.32 741005 0.24 7415373 0.90 740107 1.00 4532 055 CA07002 1210 9C1413 0.75 1043560 5.10 21076 5.00 CONTROLLER 0.80 7043810 710 TMS999512.00 SOUND & VISION 74L008 0.24 74C150 4534 3.60 oAC1424-6 2.25 M01445 2.50 2111A-35 4.00 75451 0.50 7428 0.43 7415374 0.90 5.00 70*7000 WD55 14.50 CRT5027 18.00 741509 0.24 4536 2.50 0000800 2.25 11C1458 0.45 3.50 2114-21 3.50 75452 0.50 7430 0.30 7415375 0.75 740151 2.00 0/00806 2.25 9014951 3.50 7E41032 7.00 Z80 2.80 CRT5037 12.00 12MHZ 12.00 741010 0.24 4538 0.75 2114-31 2.50 75453 0.70 7432 0.38 7418377 1.40 740157 2.50 4539 0.75 03308 3.00 11C1496 0.70 6.081CP 0.40 Z80Á 3.25 CRT6545 9.00 741.811 1.110 2.00 71062 75454 0.70 7433 0.30 0.24 7410378 0.95 74C160 1.80 4541 0.90 1101386 MC3340P 0.60 7.00 2114-41 2.00 EF9364 8.00 1111312ZIEEEMZ IC17106 903401 050 11084 7437 741512 0.24 741$379 1.40 740161 1.80 4543 0.70 6.75 0.44 2147 3.20 EF9365 25.00 75480 1.50 0.30 ICL7611 0.95 0.65 71071 Á4o / SUPPORT 747.813 4551 1.00 9C3403 4027-3 75491 0.65 32.768KHZ1.00 7438 0.40 0.34 7418381 4.50 740162 1.80 ICL76500 4.00 4.1F10CN 3.40 11072 0.70 DEVICES 3.00 EF9366 25.00 4553 2.40 4116-15 75492 0.85 1.00MHz 2.70 7439 0.40 741$14 0.50 7415390 0.60 74C163 1.80 4555 1C17660 2.50 9650240 0.00 11074 1.10 2651 2.00 EF9367 38.00 0.44 8T26 1.20 1.8432MHz2.25 7440 0.40 741.815 0.24 7415393 0.95 74C173 1.00/ 4556 0.50 ICL0038 3.00 9050398 7.80 71081 0.35 3242 8.00 4116-20 1.50 MC6845 6.50 1.4472186 72.00 91920 5.00 11092 0.55 8128 1.20 2.00MHz 2.25 7441 0.90 741020 0.24 74183958 0.60 4076 4557 2.40 3245 4.50 4118-3 5.00 MC8845SP 6.50 4560 1.67217 7.50 91922 4.00 71063 0.75 2.4576009zIL) 74424 741521 0.24 741S399 1.00 740174 1.50 1.40 4164-15715.00 MC6847 8T95 1.20 0.70 4566 1.40 1047555 0.40 9962214 3.00 17.084 1.00 6520 3.00 8.50 741822 0.24 4164-15 4.501 8196 1.20 2.00 7443A 1.00 7410445 1.80 740175 1.50 4588 2.40 1.57556 3.40 14E529 2.20 11094 2.00 6522 3.50 SFF96364 8.00 1.20 4.20 8197 1.20 2.457605Ahz(5) 7444 1.10 741$24 0.50 7415485 1.20 740192 1.50 4569 1.70 LC7120 3.00 NE531 110170 0.50 6522A 5.50 4164-20 TMS9918 15.00 1C7130 3.00 NE544 1.90 714300 110 4164-20 4.50 8198 1.20 250 7445 1.00 741526 0.24 7415467 1.20 740193 1.50 4572 0.45 6532 4.80 TMS9927 7.50 4583 LC7131 3.50 NE555 0.22 11441003.3 036 4416-15 2.5MHz 2.50 7446A 747.827 0.24 7415490 1.50 740194 1.50 000 5.00 811595 1.40 1.00 4584 LC7137 3.50 NE556 0.50 UÁ75º 3.20 6551A 5.25 TMS992810.00 741528 0.48 4532-20 2.50 811998 TAO 2.662MHz 1.75 7447A 1.00 0.24 7410540 1.00 740195 1.50 4585 0.90 LF347 1.50 NE564 4.00 492240 1.20 68021 2.20 TM9910.00 811997 1.40 3.278MHz 1.50 7448 741030 0.24 7415541 1.00 74C221 2.50 4724 1.50 1E351 0.60 NE585 1.20 ÚM170 1.76 12.50 4816493 2.00 1.00 6829 NTERFACE 3.5795MHz1.00 741032 0.24 7415608 740244 14417 7.50 16353 0.60 56588 1.50 01.948016 6.50 5101/5501 3.70 811998 1.40 7450 0.36 7.00 2.00 NE587 1.25 10.92001* 0.75 6840 3.75 ICs 741033 14412 7.50 1F355 0.90 5516 6.50 8815120 5.00 4.00MHz 1.50 7451 0.35 0.24 7415610 19.00 740245 2.25 LF356N 1.10 55570 4.00 41920024 0.75 68840 6.00 16 000 6116P-3 4.50 ADC0808 12.00 9602 3.00 4.194MHz 200 7453 0.38 74LS37 0.24 7415612 19.00 74C373 2.25 14419 2.60 1F357 1.00 66571 300 0192003* 0.75 6850 1.60 6116LP-3 5.00 AD561J 20.00 9636A 1.60 4.43MHz 1.00 7454 0.38 741538 0.24 7418824 3.50 74C374 2.25 14490 4.20 1F13331 3.50 NE592 0.90 Ú1112034* 0.75 68B50 2.50 1919CLR 4.50 NE5532P 1.50 Ú1142068 2.00 AM25S10 9637AP 1.60 4.808MHz 2.50 7460 0.55 741940 0.24 7415626 2.25 740902 1.20 14495 4.50 6852 2.50 6264P-1522.00 3.50 0500 8.50 103038 0.30 NE5533P 1.50 0192802 1.00 6514-45 2.50 AM25152521 3.50 9638 1.60 4.9152MHz 2.50 7470 0.50 747.842 0.50 7415628 2.25 740911 9.00 LM307 045 NE5534P 1.20 0152803 1.80 6854 6.50 14599 2.00 6810 1.60 AM25LS2538 3.50 5.00MHz 1.50 7472 0.45 741543 1.50 7415629 1.40 740912 4.50 22100 3.50 19304C141 0.75 NE5534AP 1.50 U1N2604 1.10 68854 8.00 DISC 743189 2.25 A14261931 1.20 6.00MHz 1.40 7473 0.45 741$47 0.80 7419640 3.00 74C922 6.00 22101 7.00 19310 2.25 O1007EP 5.00 URC515 2.75 6875 5.00 CONTROL L E 111311 060 P1102* 5.00 UPC59211 2.00 745201 3.50 AM2615321.20 6.144MHz 1.40 7474 0.50 741548 090 7415640-13.00 740923 6.50 22102 7.00 8154 8.50 Cs 40014 .0.20 19318 I543 RC4130 0.55 Ú7C11549 300 745289 2.25 41479100C 25.00 7.00MHz 1.50 7475 0.60 741851 0.24 7418641 2.00 74C925 6.50 16319 140 RC4151 2.00 Ú71.118541 5.00 8155 3.80 40085 1.20 93415 6.00 DAC80- 6843 8.00 7.16MHz 1.75 7476 0.45 74LS54 0.24 7415642 2.50 74C926 7.50 40097 L5324 0.4 RC4195 1.50 01210 8.00 3.80 0.44 93L422 9.50 8271 P.O.A. 8.00MHz 1.50 7480 0.85 74LS55 0.24 7410642-13.00 40090 0.40 1113342 1.15 904558 055 %12206 3.50 8205 2.25 CB1-V 28.00 0.1335.2 1.30 S5688 310 492207 3.75 9342 6.00 8272 18.00 8.887MHz 1.75 7481 1.80 741$734 0.30 7415643 2.50 74ALS SERIES 40100 1.50 8212 2.20 DM8131 6.00 40101 1.25 16038 1.60 050240 9.00 %12211 5.75 FD1771 20.00 10.00MHz 1.75 741S744 0.35 7410643-13.00 1.60 PROM, DP8304 3.50 7483A 1.05 40102 1.60 LM339 0.40 SAA1900 10.00 462214 6.75 8216 10.50MHz 741.575 0.45 002240 120 053691 5.00 FD1791 20.00 2.50 7484A 1.25 7419644 3.50 7441000 0.45 40103 2.00 19310 0.00 S401022* 11.50 8224 P.A.O. 1M3584. 0.6o 29404 1.00 28122 4.00 058830 1.40 FD1793 20.00 10.70MHz 1.50 7485 1.10 741576A 0.36 741$645 2.00 74ALS02 0.45 40104 120 SFF96384 6.00 8226 4 25 1.50 19377 2.10 51460 3.00 29414 0.80 24S10 250 DS8831 1.50 F01795 2800 11.00MHz 3.00 7486 0.42 741578 0.42 741545-1 4.00 7491804 0.50 40105 8228 4.50 40108 0.4 193805.8 130 06740135 3.00 214419P 1.75 185030 2.00 058832 1.50 FD1797 2200 12.00MHz 1.50 7415834 0.70 741_5668 0.90 1.30 8243 7489 2.10 7441008 0.50 40107 0.55 103809 1.20 S6780235 3.00 214423E 2.60 14.00MHz 1.75 741585 1.70 S6780316 215424E 1.30 18S4030 2.00 088833 2.25 WD2793 36.00 74904 0.55 0.75 7415669 0.90 7441010 0.45 40105 3.20 L9381A9 3.00 8250 9.50 19382 2.00 SN76115N 2.15 2942558 3.50 748188 1.80 DS8836 1.50 WD2797 32.00 14.31MHz 1.60 7491 0.70 741586 0.35 7415670 1.80 744LS20 0.45 40109 0.00 82516 3.25 44110 2.25 L5303 3.25 0576477 6.00 254288 3.00 740287 2.25 058838 2.25 WD1691 15.00 14.756 2.50 74924 0.70 741590 0.48 7415682 3.20 74/9832 0.45 82530-5 3.50 4114 2.25 19384 2.20 S57849 4.00 24427E4 0.00 740288 1.80 1E13201 4.50 WD2143 8.00 15.00MHz 2.00 7493A 0.55 741.091 0.90 7410684 6.50 7441574 0.70 193845.1 1.00 SN76495 4.00 224428E8 4.50 8255AC-5 3.80 40147 240 745387 2.25 MC1488 0.60 16.00MHz 200 7494 1.10 741592 0.35 7410687 5.50 74419138 1.50 40183 1.00 19387 2.70 5976680 1.20 2942958 2.25 8256 18.00 15324 1.60 7.00 214441E 0.00 748473 4.75 MC1489 0.60 ,3rp 17.734M1122.00 7495A 0.60 741593 0.54 7415688 5.50 40173 1.20 SP0256412 8256 24.00 74415139 1.50 1.80 224450E 7.50 18.00MHz 1.70 7415958 0.75 4074 1.00 16391 5P4515 7.50 748474 5.50 MC3448 2.50 _:LNFRATOPç 7496 0.80 7415783 21.00 74415244 4.00 1.10 i9)120 5257C-5 4.00 40175 1.00 153025 8.20 ZN459CP 100 74S570 3.20 MC3459 4.50 18.432MHz1.50 7497 2.10 741596 0.90 74410245 4.75 16393 0.85 TÁ7130 1.40 291034E 2.00 8259C-5 4.00 40192 1.00 745571 3.50 MCS3470 4.75 R032513UC 7.50 19.969MHz 1.50 74100 1.90 7419107 0.40 74415573 2.60 40193 1.00 16139409 3.75 TA72a 1.50 22191040 6.60 8271 P.O.A. 19709 035 TA7205 0.00 D0134 23.00 745571 3.00 MC3480 8.50 R0325131C 7.00 20.000MHz1.75 74107 0.50 74LS109 0.40 74000 0.50 74415574 4.50 40194 1.00 8275 29.00 40244 1.50 19710 0.4 T*7222 1.50 214*234E 9.50 74S573Á 3.50 MC3486 2.25 DM86S641200 24.000MHz1.50 74109 0.75 7419112 0.45 74002 0.50 74410580 2.60 870301 12.00 8279C-5 4.80 40245 130 82523 1.50 MC3487 2.25 MCM66760 7.50 48.000MHz1.75 74110 0.75 74L5113 0.45 74504 0.50 VOLTAGE 8284 4.60 40257 110 REAL TIME 825123 1.50 MC4024 6.00 5N745262AN 116MHz 2.50 74111 0.55 7410114 0.45 74505 0.50 40373 1.60 8282 4.50 4000 SERIES REGULATORS CLOCK 82S129 1.75 MC4044 10.00 PX01000 12.00 74116 1.70 7410122 0.70 74008 0.50 40314 1.60 8283 4.00 6,00 001.45 0.75 MC6818P 74118 1.10 7415123 0.80 74510 0.50 IA F1020 VOLTAGE PLASTIC 10220 4.50 741_5124 1.40 4000 0.20 60097 0.75 0581749 8.50 74119 1.70 74S11 0.75 60095 0.75 OVE -VE LOW PROFILE SOCKETS BY TI WIRE WRAP SOCKETS BY TI 74L8125 4001 0.24 M5M5832RS 3.50 74120 1.00 0.50 74520 0.50 4002 016 5V 7805 0.45 7905 0.50 8V 7806 0.50 7906 0.50 74121 0.55 7415126 0.50 74S22 1.00 4008 0.70 TELETEXT 8 pn 9p 18 pn 16p 24 In 24p B pn 30p 18 97 506 24 pin 75p D15PLArS BV 7808 0.50 79013 0.50 74122 0.70 7415132 0.85 74830 0.50 4007 0.36 DECODER 14 pn 106 20 pin 169 28 pin 26p 14 p 42p 20 pn 669 28 9129 1009 4008 090 12V 7812 0.45 7912 0.50 74123 0.80 7415133 0.50 74532 0.60 15V 7815 0.50 7915 0.50 16 pn 11p 22 on 22p 40 an 3693 16 p 45p 22 pn 759 40 pin 1309 4009 0.24 DL704RED1.40 5.95020 600 74125 0.65 7419136 0.45 74537 0.60 4010 0.00 188 7818 0.50 7918 0.50 7415138 0.55 DL707RED1.40 24V 7824 0.50 7924 0.50 SA45030 7.00 74126 0.55 74538 0.75 4011 0.24 8 pin 14 pin 16 pin 18 pn 20 91 24 p 28 pin 40 90 4012 0.20 FND357 1.00 SAA5041 16.00 TURNED PIN 74128 0.55 7410139 0.55 74540 0.50 IA FIXED VOLTAGE PLASTIC T062 25P 32p 380 400 45P 60p 750 4013 0.30 SAA5050 9.00 LOW PROFILE TS. 1800 74132 7410145 0.95 74551 FND500/ 0.75 0.45 4014 0.80 5V 78105 0.30 5V 79105 0.45 1.75 TIL730 1.00 74136 0.70 7418147 74864 0.45 4015 0.70 6V 78106 0.30 12V 79112 0.50 FND507/ 8V 78108 0.30 15V 79115 0.50 117294 35o 74141 0.90 7418148 1.40 74874 0.75 4016 0.34 TRANSISTORS 251613 36P 256059 325p 1Á400V 266 12V 7415151 0.615 4017 056 TIL729 1.00 78L12 0.30 TIP29C 400 251711 36p 2N6107 659 74142 2.50 74585 4.50 15V 781.15 0.30 1A600V 309 7415152 2.00 4018 040 MAN74/ 40161 2 459 131029 45p TIP30A 35p 2142102 70p 2N6247 1009 74143 1.30 74586 1.00 4019 2A 50V 300 0.00 01704 1.00 8007 8 180 BFX30 45p 707300 400 74144 2.70 7419153 0.65 74S112 1.50 4020 2N2160 350p 2246254 1309 24100V 3Sp 040 MAN71/ OTHER BC109C 20p BFX84:5 309 71731A 400 309 74145 1.10 7410154 1.60 748113 1.20 1021 0.80 2522194 256290 65p 2A 4008 46P DL707 1.00 REGULATORS BC169C 16p 131086 7 306 TIP31C 45p 74147 1.70 7410155 0.65 745114 1.20 1022 0.70 2N22228 300 2SC1306 1009 3Á200V Sop 4023 0.30 MAN3640 1.75 *CI 72 18p BF%88 300 117320 45p 2 309 741_8156 0.65 FI04 11492u141044 52369 2501307 1506 3A 800V 72p 74148 1.40 745124 5.50 4024 0.4 BF x89 180p TIP32C 40p 74LS157 0.50 MAN4640 2.00 14430911 IA 5V 1.40 BC1778 30p 2N2484 306 2501957 90p 48100V 969 74150 1.75 740132 1.00 4025 0.24 BC179 7117334 709 7415158 0.65 MAN6610 2.00 753235 34 5V 3.50 309 51050 30p 2N2646 SOp 2SC1939 1506 44400V 1000 741518 0.70 74S133 0.60 426 0.60 786055C 54 SV 5.40 182 TIP33C 4027 0.40 NSB5881 5.70 BC 3 15p 56851 2 30p 60P 2N29045 30p 2SC2028 OOP 6A 50V 600 74753 0.80 74181609 0.65 740138 1.80 7E1112 54 12V 5.40 1028 0.50 TIL311 6.50 BC184 18p 131056 33p TIP340 90p 2N2906A 3012 2SC2029 2009 64100V 100p 74154 1.40 74151616 0.75 74$139 1.80 78Po5 104 5V 9.00 7IP34C 120p 429 0.75 111729 1.00 VARI49LE REGULAT068 BC187 300 BF 090 900 2N2907A 30p 2002078 1609 64400V 120p 74155 0.80 74151628 0.75 745140 1.00 4030 0.35 T19730 1.00 193054.0 2.90 BC212 3 160 000 39 45p 71735* 1206 252926 126 2502335 2009 104400V 200p 74156 0.90 74151634 0.75 745151 1.50 4031 7.25 MAN8910 2.50 193171 113-220 1.50 8C214 l8p BSX19 20 30p TIP35C 1400 253053 366 2SC2612 2009 25Á400V 4008 74157 0.80 7415164 0.75 745153 1.50 4032 1.00 193170 703 2.40 4033 1.20 BC237 180 02104 2250 TIP364 140p 253054 60p 314128 200p 74191854 1.10 MAN8940 2.50 1.93371 2.26 TR TACS 74159 1.75 745157 2.10 4034 SC32' 16C 11736C 253055 539 2.50 193507 1070-VAR 4.00 BU'05 1900 15071 35140 200o 74160 1.10 741S1664 1.50 740158 4035 PLASTIC 2.00 0.70 013885 OA+VAR 15.00 00330 160 BU' 08 250o 6P411 5017 2 N344 2 1409 35141 200p 74L8168 1.30 4038 74161 0.80 745163 4.00 2.50 DISPLAY 197236 0.50 80338 16p 130109 22Sp 7w1C 669 35201 2009 4037 1.10 2N3553 240p 34400V 600 74162 1.10 7418169 1.00 745169 7.00 DRIVERS 786050C 505V 5.90 00461 40p 01/1 26 150p 71P424 438 1.00 80p 2N3584 25012 35204 2000 64400V 70p 74163 1.10 7415170 1.40 748174 3.00 78110I00 SA+VAR 700 BC-477 8 36p BU'RDA 1200 T11742 40290 4039 2.50 780UIC to+VAR 2.25 650 2N3643/4 48p 2500 6A500V BBV 74164 1.20 74191734 1.00 745175 4040 9388 4.50 13051 0 50p 3.20 0.10 791100C 5A-VAR 7.75 BU205 2000 T1P54 160p 2N3702'3 166 40361.2 750 84400V 759 74165 1.10 7415174 0.75 745188 1.80 4041 0.55 9370 4.50 7901.11C IA -VAR 2.50 BC5e-B 20p BU208 200o 11055 100p 2N3704 5 16p 40595 1206 4042 0.50 8A500V 959 74166 1.40 7415175 0.75 745189 2.25 L1A3914 3.50 BW7TC6640 REGULATORS BC54BC 16p E1Ú406 145p 117120 7511 16p 40673 4043 0.80 253706.1 55p 124400V 65o 7419181 2.00 IC17880 2.50 BC549C 160 TIPI 21 74167 4.00 745194 3.00 4044 0.00 LM3915 3.50 BUX80 500o 756 2 53 708 16p 40871/2 1009 124500V 1050 7415183 1.90 503524 3.00 33C5570 196 74170 2.00 745195 3.00 1045 1.00 LM3916 3.50 TL494 BU069C 3509 117122 BOP 2N3773 2006 160.400V 3.00 BC559C 24p 220p 74172 4.20 7415190 0.75 748196 3.50 Iah 0.60 110746118 3.20 71197 3.00 1310 50p 1117,25 75p 253819 409 DIODES 164500V 130p 74173 1.40 741$191 0.75 745200 4.50 4047 0.50 UDN6184 3.20 78 540 2.50 BC 070 30p 531413 250p TIPI 26 SOp 263823 30p 4048 728000 130p 7410192 0.80 0.55 4195 0 BcY71 366 MJ802 400p T117142 120p 67127 129 74174 1.10 745201 3.20 4049 0.36 ULN2003 0.90 253866 909 TIC206D SOD 7415193 BD/ 3' 75p M.1250' 2250 TIP147 1200 95636300 209 74175 1.05 0.80 740225 5.20 1050 0.35 11192004 0.90 OPTO -ISOLATORS 2N3902 700p 1102 261375P 4051 0.05 00132 809 M12955 909 1102955 900 253904 100 0447 10p 74176 1.00 74LS194A 0.75 74S240 4.00 ULN2068 2.90 7 C.`46D 110p 4052 0.40 BD'356 400 TIP3055 0490/91 90 74178 1.50 74L81954 0.75 74S241 4.00 ULN2802 1.90 ILD74 1.30 '0LIII 0.70 5313001 2250 70o 2N3906 lap 4053 010 2.20 BD' 39 400 MJ4502 4006 11593 30p 2614036 650 0495 9p 74179 1.50 748244 5.00 4051 0.80 ULN2603 1.80 11074 '0L112 0.70 THYRISTORS 80140 406 M,1E340. 50p VNIDKM SOP 04200 90 74180 1.00 7415197 0.80 745251 2.50 1055 0.50 0102804 1.90 MCT26 1.00 TIL113 0.70 254037 659 BD189 60p MJE2955 150p VN66AF 909 270 04202 109 74181 3.40 7415221 1.00 745257 2.50 4056 0.86 75491 0.70 MC52400 1.90 111116 0.70 2541234 34411ÚV 45p 4054 4.00 BD232 600 MJE30S5 1209 VN88AF E/ 2144125 6 27p 1 N914 4p 74182 1.40 7415240 0.80 745258 2.50 75492 0.70 MOC3020 1.50 80137 3.80 84600V tBOp 480 0.70 B0233 759 MPF102 409 21%108 16p 254401.3 25p 15916 7o 74184 1.80 7418241 0.80 745260 1.00 60139 1.75 12A400V 180p 1083 0.00 00235 85p MPF103 4 40P 270300 18p 254427 90p 154148 40 74185A 1.80 7415242 0.90 745261 3.00 466 0.40 164100V 180p BD241 6pp MPF105 40p 210452 456 2E61871 500 154001/2 Sp 74190 1.30 7419243 0.90 4067 2.30 LEDS 164400V 1500 745262 11.00 BD242 609 MPSA06 30p 27%500 20p 2145081 27p 154003/4 8p 74191 1.30 7410244 0.80 466 0 75 205777 0.50 C106D 45p 74S283 2.70 4009 0.24 0.125" 130379 606 MPSA12 5043 ZT%502 20p 27p 54005 69 1.00 BPX2S 1.80 0.2" 2N5089 MCR101 36p 74192 1.10 74LS245 745287 2.25 4070 024 50380 608 MPSA13 1N4006/7 7V RED TIL209 0.12 111220 0.15 50p IT X504 22p 2145172 27p 1300 74193 1.15 7419247 1.10 4071 0.24 BPW21 280 1N5401,2 120 253525 745288 2.00 GRN TIL211 0.113 BD677 40p MPSA20 SOp ZTX552 55p 90p OCP71 1.80 TIL222 0.18 2N5191 2N4444 1800 74194 1.10 7415248 1.10 745289 2.25 4072 0.24 012440 40P MPSA42 50p ZTX652 SOp 155403/4 140 4073 0.24 101'01 212 8.20 111226 0.22 255245 40p 255060 30p 7418249 1.10 ORP12 1.20 072560 SOP 155404/5 14p 74195 0.80 748299 5.50 4075 RBC1 LEDs MPSA43 SOp 27X752 700 255401 60p 024 ORP60 1.20 155404/7 255061 32p 74196 1.30 7415251 0.75 745373 4.00 4076 0.24 51257 R 406 MPy056 306 29697 350 199 (R/G/8) 0.30 COUNTERS 255459 3012 255064 35o 74197 1.10 7415253 0.75 4077 0.25 ORP61 1.20 91337 380 MPS070 50p 45p 15920 9p 745374 4.00 COO (131 001051) 2N698 255460 609 74198 2.20 7419256 0.90 745387 2.25 4078 0.25 SFH205 1.00 BFR39 32p MPSA93 400 257064 369 255485 380 4081 0.24 7.00 74C925 74199 2.20 7410245740.7A TIL32 0.55 6.50 0F040 1 32p MPSUO6 63p 36p 745472 4.75 482 0.25 10 LED 25708 2N5875 250p '0178 0.55 74C926 6.50 01079 32p MPSU07 7474221 1.10 74152588 0.70 748473 4.75 6385 0.M BarGraph' 609 26918 450 255883 375p 27V33V 3113 74C928 6.50 3317380 74251 1.00 7415259 1.20 745474 4.00 4088 0.75 III 1.20 32p AIPS1145 90p 221930 3017 2 24602 30p lA 50V 10p 40070W 99 Red 225 72168 22.00 5E096 74259 1.50 7415260 0.75 748475 4.50 4059 1.00 TIL81 1.20 11306 MPSU65 78p 251131/2 50p 2N8052 3009 A 1001, 300 1W 159 403 0.30 Grn 2.25 ZN1040 6.70 74265 0.80 7419261 1.20 74S570 6.50 TIL 100 0.75 PLEASE ADD 50p p&p & 15% VAT TECI-íNOMATIC LTD (Export: no VAT, p&p at Cost) HAIL ORDERS TO: 17 BURNLEY ROAD, LONDON NW10 lED Orders from Government Depts. & Colleges etc. welcome. SHOPS AT: 17 BURNLEY ROAD. LONDON NWIO tCE1161.3 Detailed Price Lat on request. VIS4 ("h1: 01 208 11-- 4 linO,) TCIL'\. 122800 Stock Items are normally by return of post.

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www.americanradiohistory.com by M. Bronzite Aesthetic sub - woof er system Practical guidance with particular reference to filter design

With the latest improvements in extend to one or more wave- nately, while detectable in an recording techniques and with of 11 lengths the filter crossover fre- anechoic chamber, these phase A the potential use of compact discs quency, i.e. one or two metres. effects are very difficult to hear in B loo in mind, I felt that it was time to Thus it became necessary to gen- a reverberant environment such extend the low frequency capabil- a erate model for examining the as a normal living room - see - Single ity of my current speakers. Initial impact of gross path differences page 593 of ref.2. Similarly, the infinite discussions with a higher author- between two speakers on the problem of signal -null will also be boundary 80 1 1 ity indicated a certain lack of phase of the signals involved, and minimized in such an environ- 0 50 100 200 500 1000 enthusiasm for adding 'useless from this to evaluate the variation ment due to the multiple reflec- clutter' to her living room, but of the overall amplitude of tions that will be generated. In agreement was ultimately received signal. any case I felt that by restricting 110 reached that a coffee table could This model is outlined in the possible amplitude effects to a 100 be added to the room at any con- Appendix 1 which shows how the narrow frequency band it would venient wall location. The usual filtered performance of one be more difficult to detect any (snter-¡ constraints of low cost and small speaker can be modified to degradation to the total music or 90 infinite ¡ll boundary size completed the somewhat include path difference effects, speech signal. unorthodox specification for the 80 I and then sum the resultant out- Filter implementation design, and the notes which fol- puts. With the aid of some stand- low indicate one approach to pro- Fig. 1. There is little ard filter coefficients and a some- Recall that application of a rear - difference in performance viding such a product. what userphobic computer and facing speaker requires that the between front and rear -facing Much like impending mother- using the model already high frequency response of the loudspeakers provided input hood, the functional status of a mentioned, the curves for two fil- woofer shall be well attenuated by is limited to 250Hz. loudspeaker is reasonably self- ters are given for different nor- 250Hz. Conversely, with cur- evident at one glance, and, again malized frequencies in Fig.2. The rently available small speaker like has always been so. So i.m., results are interesting. Having systems, the low frequency roll - the first problem was to find some ignored the direct effect of dis- off occurs at about 100Hz which basis of operation where the tance on received signal 1/d) ideally should not affect the over- actual loudspeaker could be hid- for clarity, the curves also indic- all system performance. Thus a den, and this is supplied by data ate the effect of any phase change high -order symmetrical filter given in ref. 1. Copied directly (lead inversion, loudspeaker centred at about 160Hz will be from Figs 5 and 6 of ref .1, Fig .1 inductive effects) as equivalent to required, which is fully in line A sub -woofer is normally shows that up to about 250Hz path difference. Thus, A = 0.5 with the discussion on unequal required to work over a there is little difference in per- (path separation 0.54) is the path length aspects. The selec- restricted frequency range formance between a front -facing same as phi =180° in the speaker tion of a fourth -order 0.5dB rip- operating in a reverberant or rear-facing speaker of reason- coil at the crossover frequency. ple Tchebycheff filter appeared to environment. With these able dimensions. Above this fre- One could go on, but the main reasonably satisfy all the imposed assumptions, the problems quency there is a 10dB lift which conclusions are clear: (a) for any constraints. of phase distortion and path makes the approach unaccept- filter, there will always be a null at The design was carried out by difference signal -null were able for a full -range system. crossover frequency at some path way of a nostalgic trip back to the taken as less important, However, if the incoming signal is separation, and (b) the higher the classic Sallen and Key format which allowed the use of an limited with a suitable low-pass order of filter, the narrower the using ref.3 as a basis. The 3dB unusually high -slope filter filter, then a rear or floor -facing frequency band of response per- frequency was selected to be network. It is this filter speaker becomes feasible for turbation due to path differences. 155.2Hz simply to optimize the which acts to restrict the sub -woofer application, and the If, as a consequence, a high - resistor values (on an E24 grid) overall impact of path speaker, vent, control panel and order filter is selected then for the high-pass filter, while the difference effects and to wires can all be hidden from criti- another problem is introduced - low-pass equations were modi- permit speaker locations cal gaze. that of phase distortion. This is fied to allow the use of standard which can meet some decorative as well as Path -length effects related to the passage of a non - value capacitors and to generate sinusoidal signal, say a drum gain in the low frequency path. technical demands. The The central problem of sub - beat, through a signal -processing The last-mentioned - about design allows the filter to be woofer application lies in the fact circuit where the phase of the 10dB - is required to take up the embedded in virtually any that it almost certainly will not be harmonics has been changed in 6dB attenuation introduced by amplifier configuration and at the same distance from the ear the reconstituted signal with the resistive summing of the two the system to work with any as the other two speakers. It may respect to the original. With a input signals, and to ensure that existing stereo speakers. The be placed adjacent to a different steep filter system such phase an adequate signal level is pre- Active Coffee Table seems to wall and path differences may changes will be severe. Fortu- sented to the woofer power have proved a viable concept. ELECTRONICS & WIRELESS WORLD MARCH 1985 31

www.americanradiohistory.com sus WOOFER

Butterworth Tchebycheff +5dB U.wo =0.6 0 +5 - i i 1 A B C B - +5 -5 First -5dB Cl ._ - --+ ( C2 - -5 +5 Pair A o _am-, 1 C3 - +5 -5 Seçond E4 + 1 - -5 +5 pair ',+ N12 - +4 -4 First =0.8 wó `; N24 - +4 -4 Second -s \ \ All figures: % change in * \ value

1 1 -10 '

LII-Wo=,a

-15

L -20

=1 ß ' OS 10 15 o Fig. 4. Effect of varying capcitor and gain values in crossover region dictates use of 1% resistors and 2% capacitors.

Fig .4.On this basis, 1% resistors 400cm3 (Fig.19, page 314, wo=14 and 2% capacitors are used ref.4). In effect, a long -throw, throughout. 30cm diameter, 100 watt speaker is needed with suitable parame- +1 -1 0 +1 -1 0 Loudspeaker box design ters to match a low -volume box, Fig. 2. To investigate effects and the Philips type AD12250/ of path -length difference amplifier. The design approacn is In the first place it is necessary to W8 was selected as a low-cost between two speakers, on given in Appendix 2, while the define the speaker requirements component for use with a vented - amplitude response, one circuit detail is shown in Fig.3, and it seemed reasonable to aim box approach. speaker's performance was the summing resistors also serve for a 3dB-down frequency of modified to include the Box design was carried out by as the first l.p. filter resistor. about 40Hz, with a 1 watt acous- and means of equations provided in consequent phase effects One of the drawbacks of the tic capability at that frequency. the two outputs added ref.5 and repeated in Appendix 3 format adopted is the relatively With a typical 1% efficiency, this (modelled as in Appendix 1). along with the required calcula- high sensitivity in the crossover is equivalent to a driver amplifier Fig. 3. Fourth -order These equations effect- region to the component toler- and speaker capability of about tions. symmetrical Tchebycheff ively define the box and vent centred on 160Hz is ances and subsequent variation 100 watts. In addition, to meet filter requirements for a ducted system designed according to with age, and the effect of varying the 1 watt/40Hz criterion the provided that the Theile-Small Appendix 2. 3dB frequency of capacitor and gain values is illus- speaker linear displacement parameters for the speaker are 155.2Hz was chosen to allow trated for the low pass filter in volume (VD) will need to be about E24 resistor values known i.e. Vas, f5, and QT (see Appendix for definition). Equa- tion 1 includes a function of the negative ripple that may be used to extend the frequency response at the expense of a larger box requirement and a dip in the response curve. If not required put RH=0.

Practical details Once the required internal box volume is know, the actual design, style and dimensioning of the layout is open to personal choice. In this case an upright box was built using the customary glue, screw and silicone sealant. The selected amplifier and power supply (types HY248 and PSU54X from ILP of Canterbury) were mounted inside the box using rubber washers or gaskets to minimize vibration, while the 32 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com box vibration itself was reduced using an aluminium L-beam att- ached to the wall behind the speaker and a 25mm diameter rod about 1mm longer than required forced between the L section stiffening beam All dimensions are in m.m. speaker wall and the back wall close to the speaker aperture. 4208 39 These box strengthening tech- Wood 20 thick approx. niques were taken from page 93 of ref.6. The vent, comprising a flanged plastics tube was found in the plumbing department of a hardware shop. The box is fully sealed (vent apart) and entry is via the speaker opening. For this reason wiring 720 was done with connection boxes Wooden rod for ease of maintenance, with longer slightly than 285 fuses and the level adjustment inside dimension potentiometer brought to a small aluminium panel below the speaker. To avoid potential earth loops, the power lines are two - Dia. approx. 300 terminal only while the signal (to suit drive unit) input is provided by a two -wire screened cable (about five metres long), where the screen is att- ached to the aluminium panel and the rectified power ground within the speaker cabinet. Construc- tional details are illustrated in Fig.5. The filter was designed to take minimum additional power from the existing amplifier supply rails Diameter to suit 4 inch plastic pipe using two TL074 quad op -amps, (see text) and the supply circuits are shown in Fig.6. The anti -thump circuit also shown is not technically necessary but subjectively reas- suring. ences) are given in Fig.7. While location and the other speakers Fig. 5. The total cost including Vented enclosure is the responses do not fully match by providing a continuous input designed according to speaker, electronics, chipboard the design objectives, they are tone at the crossover frequency. equations of Appendix 3, and veneer came to about £ 120. probably adequate - being The level pot. is adjusted until given the Thiele -Small about 18dB down at 100Hz and the sound coming from the parameters for the speaker. Results Top and bottom of enclosure, 250Hz respectively. woofer is equal to the sound from not shown, are fashioned for The test equipment comprised The woofer is matched to its the other sources - detected at decorative appeal. the UREI model 200 automatic plotting system used in conjunc- Preamp O O Main amp. tion with an AKG type C45 1EB output ^p input microphone. With this equip- ment, the filter responses (suit- ably for gain differ- adjusted <> 15k

2N222L 47 4.-re +11.3V 12V 8dB -"\/V1r- HP 680 Filter 12V +113V unit 680 LP 2N2907 loin 47 1-.4--- woofer amp. 15k

14V 100k 20 100 1000 20

www.americanradiohistory.com SUB -WOOFER

and for the nearer source N

t, t2t2 ,P2=I2w/c G 1 1 + s ta (cp,-(P2)=(l,-I,)w/c s2 -(N-1)1 + t, t, .. t, t2 t2 t2 = A.c. 2n/w w/c where N = (1 + R3/R,), t, = R,C t2 - 1 = 4dB =A(w/w)2n R2C2, t., R,C2. This relative phase shift can be represented a) Assuming equal resistors, select suit- ri"A/f1 by multiplying the signal from the furthest able value for C1, then source by (a + jb) where wisedvn C2 = C, (T.,/4T,) m1 a cos IA (w/w) 2n1 = where m=;(1+ 1 + 8(N-1) T, /T,) b sin [A 27t1 = (w/w) b) Select standard value C', < C., which will not affect the amplitude but will then R, = 2T, ß/C, fadn add (cp, - 92) to the phase of the original it/ signal. Further, any filter can be repre- and R.,=nT,13/2C,11d1t sented as a straightforward complex where n expression. As an example:

2 B B (B -w) (N-1)} 1+J1-4 C, T'{1-TZ CZ s2 + As + B (B -w2)2 + (Aw)2 -ABw l'he above values are obtained using 2 4 6 6 1b 2 4 8 10 1 selected values of N and taking Table 1 of FREQUENCY + l (B-6)2)2 + (Aw)2J ref. 3: Fig. 8. Third -octave warbler degradation was discernible at since s = jw. Thus, if the far speaker has T, = 0.45381 say a low-pass measurements show response any location in the room. filter response, and the near T, = 0.05248 first dual element in mom is 3dB down at 43Hz. speaker has a corresponding high-pass Upper curve is for woofer plus Thanks to D.L. Hermans and H. Wilms response, then these may be expressed as N = 1.846 I for their forthright assistance and I.p. =C+jD T, = 0.18798 one existing speaker, lower particularly to J.P. Vanderreydt for his curve is for woofer only. tolerant and comprehensive guidance. h.p. _ E + jF T, = 0.37808 ) second dual element M.B. - and the effect of path length will modify the N = 1.83333 I.p. response to REFERENCES Example With f,,, = 155.2 and ß = 1.093 some sensible monitoring point. 1. Influence of Room Boundaries on Loud- (C+jD)(a+ jb) =G+jH then for the second 'dual' of the low-pass This level may then be checked speaker Power Output Loudspeakers by filter let C, = 220nF, and N =1.83333: (a) where a and b are values defined by equa- Roy F. Allison Anthology of Articles in J Then m = 1.5386, and C2 = 262nF. (b) Let and readjusted by carrying out a - tion 3. Finally the total received signal X Audio Eng. Soc. 1953-77 p.339 C2 = 220nF, then n = 1.8176 and R, _ ful frequency sweep and ensuring will be 2. 'On the audibility of midrange phase dis- 6K621 and R2 = 10K999 level is that the mean l.f. compar- tortion in audio systems' by Stanley P. X = output 1 + output 2 able to the mean h.f. level over Lipshitz, Mark Pocock and John Vander- =E+jF+G+jH Appendix 3 the range, say, 50-500Hz. kooy. J. Audio Eng. Soc. vol.30 no.9 1982 September p.580 Box design (taken from ref.5) i.e. Xrm, _ (E + G)2 + (F + H)2 ...4 The overall speaker perform- 3. Simple active filters - design procedure A. Equations World in Fig.2 this function in dB has been R'16 ance in the room was measured by M. Bronzite, Wireless March and V, = 20.6 V,,, (Q, ):, :' (10) 1970 p.117 plotted against variation in normalised fre- using a one-third octave warbler 2 4. Vented -box loudspeaker system by quency and path difference, illustrating the a = V:,:/V, attachment to the recorder sys- at any frequency as one Richard H. Small Loudspeakers - Anthol- response variation f, = f, a"" 3 tem and is shown in Fig.8, where ogy of Articles in J. Audio Eng. Soc. 1953- moves across the room (going from -X to f,=f,a"." 4 the bottom curve is for the woofer 77 p.302 + X path difference) 5. Personal calculator programs for appro- alone while the upper curve is for 1, = 2350dv2/4'V,, - 0.73 d, 5 ximate vented box design by Gerry Margo- the woofer plus one existing full - lis and Richard H. Small Journal Audio Eng. Appendix 2 with V, internal box volume (litres) range speaker. Again, not fully Soc. vol.29 no.6 June 1981 p.421 V55 driver suspension compliance (litres) meeting design spec, but a charit- 6. Loudspeaker enclosure walls by Peter Filter design (based on ref.3) f., 3dB frequency of system (Hz) able view would be 3dB-down at W. Tappan Loudspeakers - Anthology of 1. High-pass filter Articles inJ. Audio Eng. Soc. 1953-77 p.88 about 43Hz. The upper curve was Select suitable value of C, then f,, box resonant frequency (Hz) R,=T,/2Cßf,k f, loudspeaker resonant frequency (Hz) taken with the microphone placed Appendix 1 centrally in the room and its loca- R.,=2T.,/Cßfk,,, QT quality factor tion must have been particularly Phase effects of path length and fad = 155.2Hz (selected) R negative pass -band ripple (dB) fortunate because subsequent Consider two speakers distant 1, and 12 from ß = 1.093 d, internal vent diameter (mm) brief tests with other locations a receiver with a planned cross -over fre- I, total length of vent (mm) showed variations of about ± 4dB quency of f corresponding to a wavelength T, = 0.05582 first dual element of X. 'l'hen let in the crossover region. How- T2 = 0.48264 first dual element N.B. V5 , f, and QT obtained from loud- -12=AX speaker specification and in this case = ever, from the path length discus- 'l', - 0.13475 second dual element where A is a multiplier. Then 202, 27 and 0.29 respectively. sion, this is only to be expected. T2 = 0.06700 second dual element B. Design process Vibration tests were carried (I, - 12) - Ac/f = Ac.27c/w ...1 (values taken from tables 2 and 3 ref.3) Establish value of R,, to meet required f3. out with functionally related test where c is the velocity of sound. For the furthest speaker at some frequency w, 2. Low-pass filter A value of 0.42dB was selected which gave sensors placed on top of the from wavelength X, the phase at the receiver is V,, = 82 litres and f, = 40Hz equations The expressions which follow are based on speaker - coffee cups - and 1, 2 and 3. 27c the transfer function while 'cup clatter' could be cp, = 1,/X = 1,w/c Establish vent length and volume. With a detected at reasonable volume, it pipe whose internal diameter was 96mm, only in conjunction with equation 5 gave the required length of was 137mm. With an external diameter of resonance noises from the 100mm the vent volume - 1.08 litres. and from cabinet doors chatter Calculate the total inner box volume. the room windows. Vb = 821 Subjective listening was posi- Box losses (taken to be 8% V,,) = 6.61 tive. For those who enjoy a Vent volume = 1.081 `thump' - be it from beat, elec- Amplifier + supply - 0.941 tronic or classical sources - the Speaker volume (approx. truncated cone) = 3.201 added octave can certainly be i.e. Total internal volume = 93.81 detected and appreciated, and no

34 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com LEADER OSCILLOSCOPES

The Leader range of high performance LBO-523 is a dual trace 35MHz oscilloscope offering LBO -516 is a t00MHz dual trace .pope offering oscilloscopes are designed to suit most similar features to the LBO -522 plus internal graticule optimum performance at a competitive price requirements, offering comprehensive dome -mesh tube with 7kV acceleration (pda). LBO-518 is a 100MHz quad oscilloscope specification and long term reliability, yet channel LBO -524 is a 35MHz dual trace with remaining low cost. oscilloscope similar eight trace capabilities. offering comprehensive to the LBO -523 plus the added facility of delayed triggering and timebase options LBO -514A is a dual trace 15MHz bandwidth, 1mV sweep timebase LBO -5825 is a digital storage oscilloscope with a real sensitivity low cost general purpose oscilloscope LBO -525L is a 50MHz dual trace oscilloscope time speed of 35MHz LBO-522 is a dual trace 20MHz bandwidth 500NV offering comprehensive triggering and timebase LBO -308S is a battery/mains dual trace 20MHz small sensitivity oscilloscope featuring XY variable hold off facilities compact oscilloscope offering all the features plus full TV triggering normally found in a bench scope For further information contact. Thandar Electronics Limited, London Road, St. Ives, Huntingdon. Cambridgeshire PE17 4HJ, England. thandor Telephone (0480) 64646 Telex 32250 Test. ELECTRONICS LIMITED THE LOGICAL CHOICE CIRCLE 5 FOR FURTHER DETAILS.

WHY ILP7 Years of experience in audio, unique designs, world wide sales and outlets, reliable Ah/lPL E deliveryand friendlyservice BIPOLAR MODULES Ideal for Hi Fi, Full load line protection integral Heatsink, slew rate 15v/µs Distortion less than 0.01% Type Output Load Price Type Output Load Price Power Impedance Power Impedance

Watts misHY30.... ims Q 1 ( )4-8º £8.45 HY244..11Óm( )4 126.95 HY60 .... 30 4 - 8 £9.95 HY248 .. 120 8 £26.95 HY6060. 30 + 30...4 -8 £19.45 HY364 .. 180 4 £39.95 HY124...60 4 £20.95 HY368.. 180 8 £39.95 HY128... 60 8 £20.95 & it P .Itlitii MOSFET MODULES to Ideal for Discos, public address and applications with complex loads (line '`.. ; transformers etc.). Integral Heatsink slew rate 20v/µs distortion less than 0.01% Type Output Load Price Type Output Load Price Power Impedance Power Impedance Watts (mu) Q Watts (mts) Q MOS128. 60 4 - 8 £30.45 MOS364. 180 4 £45.95 MOS248. 120 4 - 8 £39.95 PREAMPLIFIER MODULES All modules are supplied with in line connectors but require potentiometers, POWER SUPPLY UNITS switches etc. If used with our power amps they are powered from the appropriate Power Supply. Type For Use With Price Type For Use With Price Type Application Functions Price PSU212 .... 1 or 2 HY30 £11.95 PSU542.... 1 HY248 £17.95 HY6 Mono Pre Amp Full Hi Fi facilities £7.95 PSU412....1 or2 HY60, 1 HY6060, 1 HY124£13.95 PSU552.... 1 MOS248 £19.95 HY66.... Stereo Pre -Amp Full Hi Fi facilites £14.95 PSU422....1 HY128 £15.95 PSU712.... 2 HY244 £21.95 PSU432 .... 1 MOS128 £16.95 PSU722.... 2 HY248 f22.95 HY73.... Guitar Pre -Amp Two Guitars plus Microphone . £15.95 PSU512 .... 2 HY128, 1 HY244 £17.45 PSU732....1 HY78.... Stereo Pre Amp As HY66 less tone controls.. .. £14.45 HY364 £22.95 PSU522....2 HY124 £17.45 PSU742....1 HY368 £24.45 MOUNTING BOARDS: For ease of construction we recommend the B6 for PS11532.... 2 MOS128 £17.95 PSU752.... 2 MOS248,1 MOS368.... £24.45 HY6 £0.95 B66 for HY66-78 £1.45. All the above are for 240v operation. FOR FREE DATA PACK PLEASE WRITE TO OUR SALES DEPT. Post to: ILP Electronics Ltd., Dept. 6 Graham Bell House, Roper Close, we Canterbury, Kent. CT2 7EP I 1 `Tel: (0227) 454778 Telex: 965780

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CIRCLE 32 FOR FURTHER DETAILS. CIRCLE 34 FOR FURTHER DETAILS. 36 ELECTRONICS & WIRELESS WORLD MARCH 1985

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there are reports that the FCC for stereo recording and the technology, to assess their NEW-LOOK are being urged to try again. BBC contemplate producing contributions. Annex M of the Merriman music and drama programmes I suspect that relatively few SPECTRUM Report of 1983 discussed the in stereo, for rebroadcasting on readers could immediately place MANAGEMENT? use of price mechanisms in their v.h.f. outlets in Berlin and A.H. Midgley (1881-1961). Yet spectrum management, based Singapore and by the increasing as a recent exhibition, "A on papers from the Radio number of overseas British genius - the inventions The report in the Financial Regulatory Department (then broadcasters who relay some of Albert Midgley" at the Times on December 24 that the part of the Home Office) and BBC programmes on their enterprising Watford Museum, Government is already actively two other Government bodies. domestic services. Relay bases amply demonstrated, Midgley pursuing the possibility of The Committee itself are now served by high -quality made a lasting mark in a string charging higher "commercial" recommended the progressive digital feeds using the Intelsat of inventions (212 UK patents) fees for the use of the radio development of more general Indian Ocean and Atlantic including starting motors and spectrum clearly has important techniques in costing spectrum Ocean satellites. lighting systems for vehicles; implications for all users of use to encourage more use of Bert Gallon sees no prospects timing mechanisms and fuses radio frequencies. The DTI has the less congested frequency of any early use of direct for weapons in two World Wars; already invited consultants to bands and to encourage the use broadcasting of sound radio the pioneering of multi - tender for a feasibility study. of less congested frequency from satellites, pointing both to electrode thermionic valves Possible changes were bands and to encourage the use international agreements that made to his design by Captain foreshadowed in last-minute of less bandwidth -demanding rule out the use of d.b.s. for S.R. Mullard in 1927 for his changes to the British Telecom equipment. While few would programmes deliberately "One-Det" "one -valve" prospectus, including the quarrel with such aims, the fact targeted at other countries, lack loudspeaker receiver; a 1931 warning to investors that the remains that increased charges of any suitable frequency master patent for the Government was considering could be used in pursuit of allocation and the high cost of production of musical tones by "some form of pricing for the Government policies having transmission and reception. He electrical means; the Kinestron radio spectrum in place of, or in little to do with efficient forecast that there would be cinema organs: the addition to the present licence spectrum management. little reduction in the use of h.f. development of high -quality fee basis." The profits of BT as for external broadcasting during loudspeakers and amplifiers for a main user of the spectrum the next ten years. electronic organs and domestic would clearly be adversely EXTERNAL Although BBC World Service hi-fi systems; the electronic affected by what would amount is carried on m.f. and l.f. for guitar; even the first British to introducing a new form of VOICES many hours each day - and tape recorder marketed by revenue collection. It .could attracts a roughly 4 per cent Boosey & Hawkes and based on amount, in effect, to a new tax Bert Gallon, chief engineer, share of the UK radio audience the German wartime on communications, BBC external broadcasting, - there seems little prospect development of h.f. biasing. His broadcasting, radio navigation, interviewed on the weekly of any formal recognition of its often tempestuous career amateur radio etc. At present "Waveguide" programme, has domestic audience, as this included work with C.A. DTI licence fees are intended to stated that construction of new would require the renegotiation Vandervell and a string of cover little more than the cost overseas relay transmitter of performers fees and, more enterprises that bought him into of administration and the less - complexes at Hong Kong and at importantly, might affect the conflict with powerful industrial than -effective regulation of the Mahe in the Seychelles is due to Foreign & Commonwealth rivals and former associates, spectrum. Government begin shortly. The stations Grant -in -Aid on which all yet the evidence that he had a departments, particularly the should become operational in external broadcasting depends. remarkably fertile and truly Defence services, are major 1987 and 1988 respectively. inventive mind seems users of the spectrum. This will give the Hong Kong overwhelming. In the early The ethics of selling a natural base a life of only ten years MIDGLEY'S 1920s he was awarded the then resource such as the radio before the return of the colony substantial sum of £14,000 spectrum to the highest bidders to China, though the BBC are INVENTIONS "Award to Inventors" for the seems questionable, akin to the hopeful that it may prove Allways Fuse used in bombs infamous window tax of history possible to continue to use the Increasing specialization, even and Mills grenades. But little that sought to make transmitters, when Hong Kong within the electronics discipline other professional recognition householders pay for access to becomes Chinese territory. with its growing barriers of seems to have come his way light. While it might, or might The two new 500kW. mutual incomprehension until now, 24 years after his not, encourage more use of Telefunken h.f. transmitters at between the users of advanced death, with the Watford spectrum -conservation Rampisham, Dorset - the analogue and digital techniques, exibition. Perhaps this was to the phasing techniques, it could have a highest power h.f. transmitters has led inevitably because is work was firmly devastating effect on some so far commissioned by the out of the general-purpose directed towards the invention services. What, for example, BBC are now in full operation. inventor/entrepreneur prepared and development of saleable would be the cost of a This follows severe delays while to use mechanical, electrical products rather then "pure" transmitting licence for the manufacturers investigated and electronic techniques in his research. television transmission with its problems with the high -power search for product innovation. 8MHz channel bandwidth? valves and aerial switching. Already it is being forgotten Would licences differentiate Search for a successor to the how much electronics owes to CABLE & DBS between fees payable for wartime h.f. transmitter the ingenuity of those who Morse, s.s.b., a.m., f.m., complex at Skelton, Cumbria is trained as mechanical or American cable -television broad -band data etc.? Would now divided between Bearley, electrical engineers but turned penetration at mid -1984 has there be individual DTI licences near Stratford -on -Avon and their fertile minds to radio been estimated at about 42 per for cordless telephones, cellular Orfordness, Sussex. reception in the 1920's. So cent of television households, radio etc.? Seven new studios have been prolific were some of the representing about 35.7 -million In the USA, an attempt a few completed at Bush House pioneers in a variety of homes. The providers of years ago to introduce revenue - where the BBC has taken over disciplines that it is very premium subscription channels, raising licence fees for the use the entire building. difficult, even for those such as Home Box Office, of the radio spectrum failed, but These are acoustically suitable interested in the history of continue to complain of large ELECTRONICS & WIRELESS WORLD MARCH 1985 37

www.americanradiohistory.com COMMUNICATIONS COMMENTARY

numbers of illegal viewers by "special offers" and discounts but also some significant loss in IN BRIEF means of unauthorised cable found on similar equipments of flexibiity - and possible the USA. One result has been disappointment for those taps, reception of microwave The New Year's Honours List that a significant number of importing their own equipment. (2.5GHz) multiplex distribution brought a well -deserved British British amateurs have found it It means that the "black boxes" systems, and 4GHz reception Empire Medal to Mrs Frances cheaper to buy equipment no longer can form the basis of from distribution satellites. Woolley, G3LWY, for her overseas and then bring it into an experimental rig. There appears to be a services to the Radio Amateur the UK as a personal import. The rush to counter rising significant market in decoders Invalid and Blind Club of which if necessary, modifying it costs by adopting new that overcome the relatively Then, she has been honorary crude encryption systems in use to suit UK standards, manufacturing processes is also Secretary for many years.. . regulations or practices. leading to a succession of new in the USA. HBO however is British amateurs continue to could prove a major models, rather than progressive supplying some 10,000 What encounter difficulties that to this practice and modification of established descrambler units for the Video disincentive appear to be due more to which also has implications for models. The Yaesu FT101 Cipher 2 system for satellite interference problems than to the more experimentally - transceiver and FRG7 receiver distribution to cable network questions of environment when minded amateur is arising from for example were marketed for operators. applying for planning optical fibre the new forms of hybrid many years in various versions An experimental permission to erect masts and construction, including the use staying on the assembly lines network is operational in towers, though in several cases of chip -type, surface -mounted "until their metal stamping Biarritz, France, providing 15 recently local authority refusals now in growing use tools were completely worn channels and a videophone assemblies, have been overturned on for this class of equipment. down" to quote Kjell Strom. service to some 1500 appeal... The "Sir Walter This follows use in subscribers. TDF is increasing its successful Raleigh" which will recent years for consumer the amount of subtitling for the circumnavigate the world during electronics such as the Sony hearing -impaired to about 12 the next four years for "Walkman" etc. hours per week, and has placed RSGB IN- "Operation Raleigh" will For the customer, the use of a bulk order for 30,000 Antiope operate on the amateur bands these techniques has the FIGHTING decoders. The UK, however, as GB2SWR/MM... The Post advantage of countering the would appear to remain well Office is now providing cost in Japan of ahead in the field of broadcast rising amateurs, as they renew conventional printed -board The 1984 annual general their teletext with decoders still licences, with a new "Amateur assembly, offering consistent meeting of the RSGB proved, in significantly below the cost of Radio Validation Document" to performance and excellent some ways, a rather the comparable Antiope units. provide a wallet -sized means of as well as the disheartening occasion with an The launch of the pre- reliability proving current validity of the possibility of packing even more undue amount of the time taken operational French direct - licence and for notifying the been complexity into very compact up with procedural wrangles broadcasting satellite has Post Office of any change of units. over matters that never became put back to allow more time to address, etc... NASA has There is little doubt that the clear to the majority of those develop the high -power confirmed that Tony England, new forms of automatic present. Simmering beneath the travelling -wave -tube package WOORE, will operate from the following the problems when it assembly and hybrid surface was a split between Council members over the Space Shuttle during the 51-F was used in the Japanese microelectronics have come to mission now tentatively equally there is no election of Mrs Joan satellite launched in January, stay. But scheduled for July 1985... The doubt at all that it is no longer a Heathershaw, G4CHH as the 1984. The alternative German West Kent Amateur Radio simple matter to introduce any 1985 President, reversing an t.w.t. has still to be tested in Society is planning an modifications, or to earlier (disputed) appointment orbit. expedition this summer with a troubleshoot and repair such "by acclamation" of Ingemar view to attempt to make a equipment without access to Lundegard, G3GJW, to the 144MHz direct two-way contact specialised techniques. post. This all rather across the Atlantic, a feat that the chip overshadowed the news that the For example, has so far defeated the efforts carry RSGB has obtained from the of components no longer any many amateurs. identification; the parts are held DTI the concession (for one Amateur An attempt is to be made to in place not only by dip year from April 1, 1985) that revive the meetings of the Radio soldering but by epoxy Class B licensees may apply to the society for a letter of Radio Amateurs 'Old Timers' adhesives which are Association. Although the subsequently oven -hardened variation to their licence weekly 3.5MHz on -air net and then further hardened by permitting the use of Morse (3570kHz, Tuesday, 11 a.m.) from the dip soldering. code on frequencies above the heat continues there have been no There is thus virtually no way in 144MHz with a view to on -air STUCK WITH IT! meetings since the death of which an owner can himself training, etc. The AGM also "Uncle Vic" Corsham, G2UV. In the December issue I drew remove or change components, saw an award presented by The possibility of a meeting in attention to the effect of the even for what has in the past IARU Region 1 and the RSGB's the Midlands this Spring is falling pound/yen and pound/ been the relatively simple "Calcutta Key" to C.E. dollar exchange rates on the Godsmark, G5CO. being mooted... The three modification of v.h.f./u.h.f. remaining operational Russian cost of amateur radio etc. In some The Marconi Medal was channel spacings amateur satellites in orbit, TS5, equipment in the UK indeed the factory awarded to a group of West - equipments not even RS7 and RS8 are each active on costs have gone up still further equipment once it German amateurs, who as can modify only two days of the week in since then. The policy of the has been dip soldered. DFOEME, have specialized in major Japanese firms in Thus are thus, as Kjell W. 2.3GHz "moon -bounce" work order to limit the now failing power sub -systems. One appointing in the UK Strom, SM6CP1, the Yaesu using an impressive 10 -metre is on each day "authorised distributors" European manager based' in diameter parabolic reflector dish satellite switched except Wednesday when capable of servicing and Italy, points out, both aerial. The RSGB has changed there maintaining their equipment has advantages in better value for the name of its headquarters is no operation.. . also tended to maintain retail money, higher reliability etc. in building at Potters Bar from prices, without the many the manufacturing techniques Alma House to Lambda House. PAT HAWKER. G3VA 38 ELECTRONICS & WIRELESS WORLD MARCH 1985

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IDA AC/DC. 20M ohm £85.00 tester 91-zcm display £179.00 Meg ohm Basic 0.2°m Plus continui y tester IR)£95.00 IAC adaptor option £6.951 3035 Single trace 15MHZ 13cm MX563 True RMS 3'2 digit 30 ranges 10A AC/OC TM356 31G digit LCD 29 ranges as TM355.3000 hour battery Meg 15"I display component tester £198.00 20 ohm. 20HZ to 30KHZ 0.1 °4uic(R)£155.00 life 'supplied) £95.00 MX5754', dIpll True RMSm 21 anges t0A AC/OC. 3132 Dual 20MHZ trig to 40MHZ.2mV/div 130mm 151 TM351 31/7 digit LCO. 29 ranges. 0.1% basic. Ranges as above. up to50KHZ0.D5°° basic (RI £175.00 display. algebraical add/sub Reg OC 0/P's 5V AO 2000 hour battery life. £115.00 12V. Built- in component comparator £297.00 ANALOGUE MULTIMETERS LED COUNTERS SCOPEX General range ('mirror scale)lUK C/P 65p) (UK C/P 65p) (AC adaptor included) 4 portable 8 digit LEO counters. 1ir-.- 14015 Dual 15 MHZ 5 tube HC1015 15 range pocket IOK/Volt METEOR mains or battery . I x z 0.IHZ resolution TV SYNCH Z MOD £325.00 meg ohm £7.78 Size 219 240 98mm. 5mV sensitivity H range 20K / Voll IDA DC A M 102BZ' 22 100 5HZ to 100MHZ £99.00 ._-®... OIO F6 As above plus titled plus cont. Buzzer 10 Meg ohm £12.61 600 5HZ to 600MHZ A&8 inputs £126.00 0.2HZ to 200 KHZ Function Generator £425.00 ETU30002U range 30K/V 1000MHZ I GHZI 858 inputs 1000 5HZ to I £175.00 12A DC 12 meg ohm £18.26 THANDAR NH56R 22 range 10K/Volt 6 Meg ohm £11.26 Options: 6 NICAOS £10.60 NF pickup Aerla £8.50 2 year warranty 830A' 26 range 30K/Volt I OAC/DC 10 Meg SC 1 10A 10MHZ battery ohm £21.70 portable 32 x 26mm display 360TR' 23 range bench 100K/ Volt. large scale. FUNCTION GENERATOR 93. i;N:7c=r;;ififcb O 65p( with batteries 10A AV/DC plus life tester. 10 Meg ohm £39.13 (UK C/P £165.00 range de luxe 100K/Halt 10A AC/DC. JUPITER 500 Function generator 0.I HZ to 500KHZ or better. AT2100' 31 r lUK past. etc. £1.501 100 Meg ohm £30.39 Sine. square. triangle 0/P to 30 volts. TTL 0/P. DC offset OOo luxe plus Hle 15V variable. Eat AM and sweep facilities 220/2400 AC 0 OPTIONS Carry case £5.95 AT 1020' 18 range de 20K/Volt tester.5 Meg ohm £19.57 operated. £110.00 AC adaptor/charger £6.95 Nicad pack £11.00 L' YN360TR 19 range 20K/Volt plus Hle tester 1 Meg ohm £13.87 DIGITAL CAPACITANCE ASC11 KRT5001' Range doubler 35 range total 10K/Volt AUDIO AND RF KEYBOARDS IDA OC 20 Meg ohm £19.09 METER GENERATORS 69605 Compact. 64 key ST303TR 22 range 20K/Volt plus Hle tester 12A 0016013 0.1 pt to 2000 mfd LCD 8 IUK C/P £I.001 function Hall DC 1 Meg ohm £18.26 ranges 3'/ digit. £60.43 (UK C/P 65p) 5 keys. AUDIO Professional series In Mock. ask for leaflet effect keyboard with Metrix'ITTI Bench version 41/2 LCO 1 pl to CM200 digit LEADER LAG27 5 band sine/square 0/P 0/5V reprogrammable ASCII output decoder 127161 2500 mfd 6 range £69.00 (UK C/P £1.00) RMS [list 0.05°%.20HZ to IMHZ £93.00 key frame for good rigidity. Negative COMPUTER POWER SUPPLY EPROM Steel LEADER LAG120A5 band 10HZto1MHZ100.311 going strobe. Requires 5 volt 12 volt supplies. Switched mode. Stabilised. Sell protecting S/C RMS Into 600 ohm 005° dist sine/square £155.00 E1.001 protected. etc. 220/2400 AC 5113.3A 12V 2.4A IUK C/P £21.70 LAG1255 band 10HZ to IMHZ to 0.3V 40% cycle -5V 0.5A -12V 0.58. Suitable Apple AC CLAMPMETER LEADER RMS Into 600 ohm sine/square/burst signals 0.03°/e replacement C/P £1.501 £50.00 0/3000 0/500V AC 0/1K ohm IUK X330.00 2070 COMPACT 58 KEY ASCII KEYBOARD Total 9 ranges with carry case and diet TRIO A6202A 4 band 20HZ to 200KHZ 10V RMS Contactless capacitive high reliability keys. Full 128 VARIABLE POWER lead 0/P 0.5%dlot CR OSC 0/1011 pp 0/P £89.00 ST300 £30.87 (UK C/P 65p) ASCII codes. Steel key (rame for positive rigidity. wet, TRIO A62035 band 10HZ to IMHZ 0.1% dist 0/7V £71.74 I mS strobe. single 5 volt supply. 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Very heavy gauge (.251 plastic with LARGE RANGE IN STOCK AVAILABLE FOR MOST ITEMS SEND 1.5 to 200MHZ 6 band metal base. Attractive silver grey finish. LEAFLETS 1008 for small or large quantities. LARGE SAE (UK 25p) for latest catalogue. 1UK C/P 65p1 IUK C/P £1.781. £19.95 Tel: 01-723 ordure welcome ALL PRICES 'SUPPLIERS OF ELECTRONICS FOR EVERY PURPOSE I 'Seed EXCLUDE VAT ORDER BY POST OR PHONE 301 Edgware Road. London. W2 VISA .1 Test Equipment. Audio. Communications 01-724 3564 404 Edgware Road. London. W2 Up of £I000instantcredit 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, 1st Floor. 406 Edgware Road. London W2 1 ED CIRCLE 19 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MARCH 1985 39

www.americanradiohistory.com NEW from Kontakt The capability and effect of r` compressed air in a handy can. TENSION 67 efficiently removes KONTAKT dust and deposits from electronic components, electronic and electrical appara- tus, microscopes, medical equipment, cabinets, etc. Abso- lutely no spray residues. No compressed airline needed. With plug-in nozzle even blows around corners. Ready for use in the service kit. Kontakt 60 Dissolves oxides and sulphides, re- moves dirt, oil, resin and traces of metal abrasion. Protects against erosion. En- sures perfect contacts. Kontakt 61 Special cleaning, lubricating and anti- corrosion fluid for NEW (non oxidised) and specially sensitive contacts. An ex- cellent lubricant for all electrical and electro -mechanical systems. Spray Wash WL A rapid cleaner for reliable washing and degreasing of electrical equipment and components. For removal of dirt, grease, oil, soldering residues and other impuri- ties. The Microvalue Group dealers shown ALSO AVAILABLE: below represent part of the Gemini network. A COMPLETE RANGE OF INDUSTRIAL AEROSOL SPRAYS For expert advice and full details on the Gemini System, contact your nearest dealer SK10 Soldering Lacquer, K75 Cold Spray, K70 Plastic Spray, K88 Oil Spray, K701 Vaseline Spray, K90 Video Spray, K33 Graphite Spray, K100 Antistatic Spray, today. K101 Fluid Spray and, of course, Positiv 20 positive photo resist for printed circuits. AMERSHAM COMPUTER CENTRE LTD 18 Woodside Road, Amersham, Bucks HP7 OBH

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40 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com Every card's a winner. The versatile 80 -Bus system can be used for a host of applications: Process Control, Batch Counting, Robotics, Colour Graphic Displays, CAD/CAM, CNC; In Manufacturing, Telecommunications, Instrumentation, Laboratory Testing, Security Systems, Plant Control, Data Collection and Distribution. Also, in smaller companies it can handle Accounts, 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 with 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 cards below, plug yourself into our dealer network to discover how opening a new pack of cards with Gemini will help you pick a winner.

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ELECTRONICS & WIRELESS WORLD MARCH 1985 41

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CIRCLE 114 FOR FURTHER DETAILS. CIRCLE 8 FOR FURTHER DETAILS. 42 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com LOGIC SYMBOLS

by Ian Kampel, The new logic M.I.E.R.E. symbols -1 The national standards of all major technological countries are changing to comply with a new international standard. This new standard will affect everyone concerned with digital electronics, and the implications of the change should not be underestimated - especially if digital electronics is your profession. Be warned: the new logic symbols are far more than mere substitutions for existing symbols - they take an entirely new approach to representing logic circuitry. Is it all for the better or for the worse? Read on!

This is the first of three articles vice Publications (AESPs) to France, Germany, Nether- intended to make readers aware British Standard 3939: Section lands, Japan, the UK and USA of the new logic symbols. This 21 (Issue 2), Binary Logic Sym- and many more now intend to first part concentrates on bols, which went part way to con- bring their own national stand- explaining why the symbols are to forming to the previously ards fully or broadly in line, which change, indicating the advan- mentioned American standard, stresses the importance of this tages and disadvantages, and but led us into all kinds of diffi- subject to every digital engineer. explaining the basic principles. culties because it was not a full There are other countries act- The second part will explain some specification: too many symbols ively involved in the discussions of the more complex symbols and were missing for it to be rigidly whose intentions are less well features such as the common - applied. If I say here that this known, but in due course, may control box and dependency British Standard uses rectangular well also conform. notation, and the third part will symbols, I know that many will Anyone working for a large discuss trends and the way ahead imagine they are familiar with it, company has seen from personal using the new symbology. assuming that it simply substi- experience that committees gen- tutes rectangular symbols for erally design camels with surplus The background previously existing charac- humps and that international My own interest in what I here teristically shaped curved sym- committees can never see beyond term the `new' logic symbols bols. In fact, this notion harks the humps. It is therefore no Acknowledgements stems from documentation work back to a still earlier standard, for mean feat for a body to have The author is greatly indebted to undertaken on Concorde many Issue 2 of BS3939, Section 21, is reached the stage where all these Mr D.B.J. Hicks of the British years ago for American use. far more sophisticated than that: countries are in broad agreement Standards Institution, Messrs C.J. These particular handbooks were it was, in fact, a half -way house on a new standard. Such a body is Stanford and L. van Rooij, General Secretary and Deputy General written to the American ANSI towards the standard that I now the International Electrotechnical Secretary of the International Y32. wish to talk the (EEC), based in 14-1973 Specification about, standard Commission Electrotechnical Commission, for (equivalent to IEEE Std 91- that BS3939 is due to conform to Geneva. their invaluable assistance in the 1973), and although I had been in very shortly. After a decade of discussion, a research work for my book, Mr N. the field of technical docu- The fact of the matter is that for document entitled IEC Warnock -Smith of Butterworth mentation for some time, never- over a decade there has been Publication 617:12, Binary Logic Scientific Ltd, for his kind co- theless they then represented a international co-operation in an Elements, has been published, operation in the use of illustrations major deviation from any previ- active attempt to develop an and it is this document which is to from my book for this article, and penned the ous understanding I or my col- internationally acceptable stand- be the basis of numerous revised Ms J. Molyneaux, who excellent illustrations. leagues had of logic symbols. I ard for logic symbols that would national standards. Like the Mr Kampel has produced a book on it did baffle be recognised throughout the many countries must confess serve to United Kingdom, this subject, entitled A Practical us initially. world and would be versatile intend to publish `Chinese copies' Introduction to the New Logic In more recent years I have enough to cope w:th the ever of this source document. The Symbols" (Butterworth Scientific, been involved in documentation increasing complexity of modern digital engineer is therefore prob- 1985). It is based on IEC work for Army Equipment Ser- digital circuits. ably the first in the field to get Publication 617:12 -Ed. ELECTRONICS & WIRELESS WORLD MARCH 1985 43

www.americanradiohistory.com LOGIC SYMBOLS

GENERAL QUALIFYING SYMBOL PREFERRED LOCATION FOR GENERAL QUALIFYING SYMBOL OUTLINE EXTERNAL EXTERNAL LOGIC STATE LOGIC STATES

INPUT LINES OUTPUT LINES QUALIFYING SYMBOL NEGATION SYMBOL

ALTERNATIVE LOCATION FOR GENERAL QUALIFYING SYMBOL INTERNAL LOGIC STATES POSSIBLE LOCATIONS FOR QUALIFYING SYMBOLS

t t a

t d t b

t c

t GENERAL QUALIFYING SYMBOLS (a) (b)

Fig. 1. Symbol composition. what amounts to his own interna- Good news or bad news? tioner' is the fact that the Ameri- Length/width ratio is tional language. At this juncture you will no doubt can manufacturers of digital com- arbitrary. I use the term `language' advi- have mixed reactions if all this is ponents are well embroiled in the sedly, for the new logic symbols news to you. Is it good news or transfer to the new symbols on Fig.2. Binary logic element are really just that. Admittedly it bad news for the profession? their data sheets, and even the -a Nand gate with one is a sign -language, but like any What was wrong with the popular most determined ostrich will negated input. true language, it does allow the `curvy' (MIL -STD -806B) logic therefore be forced to learn the user freedom of expression. That symbols which have proliferated new language - or take early Fig .3. Combination of is where it differs so greatly from so much in recent years? And retirement on a reduced pension! symbols. Logic connections anything that has gone before. before someone else points it out, I was a design engineer for must only pass edges in I did prefer to use the latter stand- many years and I know such a direction of signal flow. New frontiers ard (also to be seen in this jour- change will not be popular. I am The new logic symbols open up nal), in my recent book: Practical presently involved with design Fig.4. Embedded symbols. new frontiers and new levels of Design of Digital Circuits engineers on a day-to-day basis, sophistication. They enable dia- (Newnes Technical Books, and I still know the change is not Fig.5. Illegal (a) and legal (b) grams of complex logic circuits 1983). The reason for that popular. How could it be when mixtures of polarity employing similar circuitry to be choice, as explained in an appen- such persons are already over- indicators and negation dramatically reduced in size and dix, was simply that these sym- worked, underpaid, and un- symbols. complexity, without any loss of bols were so familiar. Had I intro- appreciated? But that is where detail. Furthermore, as I intend duced the new logic symbols, it the argument must end, for I am to show in the third article of this would have completely detracted talking of a fait accompli. It is series, it enables circuits to be from the principal aim of the here and it will stay. There has represented at different levels of book: to teach design principles. been too much commitment for detail with each and every level For do not underestimate the retraction now. Your only accurately depicting the overall complexity of the new logic sym- concern should be how long it will logic functions. This can be use- bols: learning to use them is a be before it affects you. So far ás fully employed in industry, for a subject in its own right. the international committees are systems engineer can design a Let me give you the bad news concerned, it is too bad that we're high-level circuit and pass this on first. Yes, you do need to put your still trying to get to grips with to a project or equipment engi- thinking cap on again in order to decimalisation in Great Britain. neer; he, in his turn, can create a learn to use and interpret the new There is more bad news. From medium -level design showing logic symbols, for unfortunately, my own researches, it is plain more precisely the methods of complexity is the price you have that this matter will come as implementation which he can to pay for sophistication. Military somewhat of a bombshell to the pass down to a design engineer; projects will increasingly call for majority of engineers in this the latter can then produce a the latest standard on circuit dia- country, not to mention lectur- component -level design. In all grams and in technical hand- ers, whose duty it will be to educ- cases the new logic symbols may books. Commercial products will ate themselves before their stu- be employed, and in each level increasingly require use of the dents take them to task. I say conversion, there can be no new symbols to give the docu- again, the new logic symbols are doubt as to what is required. All mentation immediate interna- not mere substitutions for pres- this can be achieved without tional status. But even more ently known alternative symbols words or even block diagrams! significant to any `digital practi- - except at the simplest level. 44 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com To my mind, they represent the your appetite as it were - and, where the function is completely need for a new endorsement sub- hopefully, to convince you that defined by the qualifying symbols ject for those studying digital this is not something that can be associated with inputs and electronics. ignored. outputs, thereby making a Now for the good news. The Symbol composition general qualifying symbol new logic symbols are logical! Symbols are used to represent redundant. They also offer a very clever binary logic elements. As Figure 2 depicts an example of means of simplifying circuitry in depicted in Fig. 1, a symbol com- a simple binary logic element: in a order that a circuit function can prises: an outline, a general qual- positive logic convention this be more easily comprehended. ifying symbol denoting the func- represents a Nand gate with one block Where a present-day dia- tion of the binary logic element, negated input (the familiar circu- gram and associated text is and input and output lines. The lar qualifying symbol indicates a circuit func- needed to explain outline is rectangular and the negation or inversion). tion, the new logic symbols - length: width ratio is arbitrary. In order to reduce the space equally straighforwardly repre- The preferred location of the gen- requirements on diagrams, sep- sent and fully define the circuit eral qualifying symbol is at top arate symbols for basic functions function without the absolute centre of the outline, although a may be abutted provided that need for words. Where a complex central location is also accept- there is no logic connection device was previously repre- able. between logic elements where sented by an annotated rectangle It is preferred to have input the common side/s of their out- which further reference required lines on the left of an outline and lines is in the direction of signal a it, to data sheet to explain many outputs on the right of an outline, flow, and that there is at least one such devices may now be fully so maintaining left -to -right flow. logic connection between the ele- defined by their symbol. There is Unless otherwise unavoidable, ments where the common side/s Fig .6. Examples of also great bonus. The another inputs and outputs should be of their outline is perpendicular to combinative devices 7400 logic can even - new symbols placed on opposite sides of an the direction of signal flow. and 7437. remove problems associated with outline. In special cases where a This is made plain by the exam- positive or negative logic conven- horizontal symbol is approved ple given in Fig.3. It will be seen Fig.7. Example of a more tions. What more could an engi- (e.g. counters and shift registers that there is 'at least one' logic exotic symbol - octal flip- neer ask for? - save something although vertical orientation is connection between element d flop with common enable, the simple! - still preferable if possible), a top - and each of elements a, b and c, 74LS377. The learning curve to -bottom data flow is preferred. although there is no logic connec- Because of my involvement in the Whilst a general qualifying tion between elements a and b or Fig.8. Even more information technical documentation indus- symbol is normally required b and c. in one symbol - the 74690 try, I have been aware of the within an outline in order to Another way employed of gain- 4 -bit synchronous counter forthcoming problem for some specify the function of that ing space is to embed one symbol with output registers and time. Apart from an engineer's element, there are circumstances inside another, as shown in multiplexed tri -state outputs. revised national standard, there seems nowhere for him to turn to for practical help in this situation for, with the best will in the world, a standard cannot be regarded as bedtime (or even cof- fee -time) reading. Not that this is in any way meant to detract from the value of any given standard, for such is needed to clearly define requirements. By virtue of the need to unambiguously define, however, such works >ct

cannot be informal in their EN approach and are inherently 2 different from the ideal teaching 1D document which takes one idea at EN23 MUX a time and develops it. R/C " G21 e Brief notes on the new stand- lii°LR R1çÇ2]]11 RCK 9 e ard may be found in such >CRTDIV 10 13 publications as The TTL Data ct R6 IC Book for Design Engineers razau M1(LOAD) 17 (Texas Instruments), but when it M2 [COUNT) le is taken into account that such a ENT G3 3CT=9-Z22 22 19 RCO treatise is far shorter than the ENP G4

actual standard, it is clear that it t CCK >C5/2,3,4. is far from exhaustive. It really Z r r r does need a full-length book to do 6 110 12 21 the subject justice. A= 1,50 (I) 6il 23V OA n Since the standards are e -` (27 16 weighty tomes, it might be sup- CS I1,1 c e Is posed that I cannot tell all in three D t et magazine articles. The aim here is therefore to give you a taste of the new logic symbols - to whet ELECTRONICS & WIRELESS WORLD MARCH 1985 45

www.americanradiohistory.com LOGIC SYMBOLS

Fig.4. Any symbol may be placed A polarity indicater is a trian- indicators show that a low voltage able (i.e. when no polarity indica- inside another providing that the gularly shaped qualifying symbol is required on the top two imputs tors are used). result is unambiguous and the placed on an input or output line to produce corresponding inter- relationship between the two is such that the apex points in the nal 1 -states, whereas the two The next point to note about Fig. clearly defined either by position direction of signal flow. The lower inputs require high levels 6 is that it is unnecessary to or by internal connection lines. polarity indicator on an input or on their inputs to produce inter- repeat a general qualifying output implies that the internal nal logic 1 -states. The internal symbol in an array of identical Logic convention 1 -state corresponds to an exter- negation symbols have their elements. The '&' general I think it fair to say that today nal L-Ievel (i.e. low level). Thus customary logic significance with qualifying symbol in the upper there is a general preference for a the polarity indicator effectively respect to the common element, element of the 7400 device is positive -logic convention, which converts between external physi- and the final output produces a taken to apply to all four implies that the H (high) level of a cal voltage levels and internal high level for a logic 1 -state. elements. The same applies for physical quantity - such as vol- logic states. the 7437, but here the buffer gen- tage - represents the logic If the decision is taken to Combinative devices eral qualifying symbol is included 1 -state of a binary variable, and employ polarity indicators on a Figure 6 depicts two simple in the upper element to signify its the L (low) level represents the circuit diagram then logic con- combinative devices, and serves driving capabilities. logic 0 -state. A negative -logic ventions become superfluous - to illustrate a number of points. This is also a useful point to convention is the converse of they no longer apply. By implica- Firstly it serves to show that the highlight the fact that the polarity this. Because the physical tion, if this is undertaken, there lowest level of representation indicator has the inherent prop- aspects of a circuit vary according should be no negation symbols on with the new logic symbols is at erty to indicate signal flow. As to the convention being applied, any inputs or outputs, since their device level: here are depicted such, its presence on a particular it is essential that the convention presence demands a logic con- the 7400 and 7437 devices, signal line can make the need for a is always clearly defined. Ideally vention. referred to as quad 2 -input posi- directional arrow (required to it should be stated on every dia- The use of polarity indicators tive Nand gates and quad Nand indicate non-preferred direc- gram, but in practical terms, it does not mean that negation sym- buffer driver respectively. Note tional signal flow) superfluous. should be sufficient to state the bols are a total anathema on dia- that the symbol for the 7400 convention in use within a single grams, and this is a potential employs external negation sym- Conclusion document or working environ- source of confusion. It must be bols and therefore this means That concludes this basic intro- ment. The only real justification remembered that you are dealing that it is necessary to qualify the duction to the new logic symbols. for using a negative -logic conven- with pure logic within a binary logic convention as positive - in the next article I shall consider tion is where a negative supply is logic element, and here polarity for in the negative logic conven- some of the more complex used for logic devices. has no significance! So negation tion we would have an Or gate aspects including dependency Providing that the logic con- symbols are always employed with negated inputs. On the other notation and the common control vention has been defined, the within elements to indicate nega- hand, the 7437 is shown with block, but in order to illustrate conventional circle may be used tion, even if polarity indicators polarity indicators on the out- the fact that the more complex as a qualifying symbol to indicate are employed externally. puts, signifying that two high logic symbols are far from direct negation. If the situation arises Figure 5 depicts legal and ille- inputs on any gate input produces substitutions of existing sym- where both logic conventions are gal use of polarity indicators. To a low on the output. The gates in bols, I leave you with a foretaste mixed - say at the interface the left of the diagram (a) a mix- both devices perform identical of two of the symbols to be dis- between two manufacturers' ture of polarity indicator and logic functions and are here rep- cussed in future parts. Figure 7 equipments - then a more com- negation qualifying symbols are resented in two different ways. It depicts an octal flip-flop with plex situation arises: one that shown: the presence of so much is necessary to become accus- common enable and Figure 8 causes endless confusion with as a single polarity indicator on a tomed to interpretting diagrams shows a 4 -bit synchronous coun- previous methods of logic repre- diagram bans the use of the nega- of either form, and both will ter with output registers and mul- sentation. tion symbol on any inputs or out- therefore be used in this series. tiplexed three -state outputs. The new logic symbology over- puts, since it implies no logic con- To avoid any confusion, it may These symbols employ both comes this problem in a very ele- vention in use. To the right of the be assumed that throughout this dependency notation and the gant fashion by the use of polarity figure (b) is shown a legal mixture series, a positive logic conven- common -control box, but more indicators. of the symbols: external polarity tion is used when such is applic- of that in due course!

LITERATURE RECEIVED

'The biggest variety of surface -mounting transistors and for £6.90. B&J Sound, Kirkby Individual pages may be retained in semiconductors in any retail shop' diodes is available from Ferranti Lane, Tattershall, Lincoln. the computer's internal memory or is the proud boast of Cricklewood Electronics Ltd., Fields New Road, LN4 4PD. EWW 260 on disc and may be called as Electronics. It certainly seems to be Chadderton, Oldham. OL9 ONP. required. Using this system, the bourne out in their stock list/ EWW 259 virual and physical address spaces catalogue which also lists the are divided into 32769 pages each passive components, hardware, of fixed size, 512 bytes. The series tools and other equipment that they also includes the N932091 floating stock. Telephone, mail-order and A new series of Unix -based point unitto provide 32 and 64 -bit credit-card purchases are acceptable A state-of-the-art home built computers, built around National floating point operations. The three as well as callers to the retail shop preamplifier is available as a kit Semiconductors' 32000 family of chips are really a single unit and as at Cricklewood Electronics Ltd., 40 from B&J sound. The design is processors and peripherals, is v.l.s.i. methods improve, they Cricklewood Broadway, London. modular and may be tailored to described in a brochure. The could be combined into a single NW2 3ET. EWW 259 meet specific requirements or for N932032 is a 3 -bit processor which circuit. The brochure -also discusses matching existing equipment. Kit is combined with a N932082 the implementation of Genix a lists are available along with details memory management unit to give super -set of Unix. National of a power supply and a guide tp 'Virtual memory', a method of Semiconductor (UK) Ltd., 301 the selection components. Full dividing the available memory into Harpur Centre, Horne Lane, A handy reference guide to 50-23 constructional details are available pages. Bedford MK40 1TR. EWW 257 46 ELECTRONICS & WIRELESS WORLD MARCH 1985

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ELECTRONICS APPLICATIONS TRANSDUCER APPLICATIONS Storage... The Gould 1421 Digital Storage Oscilloscope (DSO). A Dual -Purpose DSO for Electronics and Transducer applications. Compare the benefits of the low-cost 1421 and its suitability for two diverse application areas, with the performance of our competitors. The 1421 has a storage -U.; bandwidth up to 20MHz-in single and dual - channel modes. ö_ : Take a look at the heavyweight performance - e details of this compact, lightweight DSO: ,` - 771 No trace degradation with time. Storage of pre -trigger information. 2MHz 8 -bit ADC for transient capture. 20MHz repetitive signal storage. 1k store per channel. x10 post -storage expansion. Pen recorder output. Single channel trace hold for waveform comparison. Conventional 'scope operation up to 20MHz. And all the usual benefits of a Gould Digital Storage 'Scope. Ask for more details now from Gould Instruments Ltd., Roebuck Road, Hainault, Ilford, Essex IG6 3UE. Telephone: 01-5001000. Telex 263785.

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AFFORDABLE ACCURACY QUALITY MULTIMETERS FROM ARMOR ANALOGUE DIGITAL 1e 1096Z MC -6010 0.5% Accuracy. Standard Model 10ADC Range, 20K(UVDC, Buzzer, Battery Test 099.50 Scale _,.._..... _...... _ _...... _...... £10.00 HC-S0107 0..25% Accuracy. TR Test Facility 19 measuring ranges £39.50 11141028 All models have full functions and ranges and Low end voltage 8 current ranges, Jack for feature: Audioo/p Voltages £11.00 20 measuring ranges. 31, digit 0.5" LED display 1.1015 Low battery indication Rugged. Pocket sized meter, for general Auto zero & Auto polarity purpose use £7.50 ABS Plastic Casing E. Tilt Stand 16 measuring ranges DC AC 10amp Range Battery. Test Leads and Manual included with Overload Protection on all ranges. each model. Battery. Spare Fuse, Test Leads and Manual FULL APPLICATION FROM:- 7/2 DETAILS ON NC 7030 ARMON ELECTRONICS LTD 0.1% accuracy DER A HURON MOUIR, 109 WEMBLEY HILL ROAD, wlnlSLKY, 11111X LIIKX HAS 8A0 £39.50 Tt4PHOIIU 01-907 4321 MAX 923065 .,,.y PLIAIle ADD 15% to your order for VAT. PIP Free of Memo. Payment by cheque with order push button

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Introducing GPIB Having first been considered some 20 years ago, GPIB could probably be improved upon but it is so well established that it is likely to remain the foremost standard for connecting instruments to computers for many years yet,

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1 General-purpose interface bus, 'IEEE bus' and called HPIB by Alt -lough still re :ewers and GPIB, is a method used its designers, Hewlett Packard too expensive logic analysers, throughout the world for linking who started its development in for most enthusiasts, these are also expensive. Besides instruments and computers. 1965. The bus is also covered relatively cheap add-ons bring having the digital control and Providing a means for both by a British standard, BS 6146. automatic measurement and interface circuits necessary for setting up instruments and Carrying eight -bit parallel quality control - or at least the computer control, the majority reading information from them data and using eight control/ bus to provide them - within of bus -controllable instruments directly back into a computer handshaking signals, GPIB is the reach of even the smallest also have manual controls and ready for processing, the bus's generally much faster than a of organizations. Equally cheap readouts which increase their main applications are in serial link and, being designed instruments and software, not cost. We are still at the stage research and development and for a specific task, it has an to mention cables, may be a where most instruments are in automatic testing, edge over other common little harder to come by. designed for manual use with measurement and quality microcomputer buses where There are a few general- GPIB compatibility available as control systems. Controlling computer -controlled purpose microcomputers like an add-on. instrumentation by computer instrumentation is concerned. the Commodore Pet, 64, 4000 Incompatibility means But as with all such standards, 8000 700, RML Link 480Z, it is not theideal solution for all Sharp MZ80K and IBS750 that The standards mentioned above faster processing - applications; the main reason have built-in GPIB interfaces only specify electrical and reduced risk of human error - using it now, some 20 years and there are some mainly for mechanical parameters for increased accuracy through for - its conception, is the large design and research, Iike the linking units together they computer correction techniques after - number of GPIB-compatible HP Technical Computers range, don't say what data passing elimination of tedious - instruments and controllers that are designed with GPIB through the bus should look repetitive tasks control in mind. Lastly, there like. Sadly, this means that convenient data storage and available. - Cost of implementing the bus are computers and controllers there is no guarantee that a hard copy is high. One short-cut is to use whose hardware and software is system happily controlling a Internationally, GPIB is a microcomputer with an add- designed solely for use in GPIB GPIB instrument from one defined by the IEC625-1 on interface such as those applications. manufacturer will work with a standard and in America by available for the BBC GPIB-compatible similar instrument from another ANSI MC1.1 and IEEE488- microcomputer, QL, Apple, instruments, ranging from tape source. Suggestions for code 1978. It is often misnamed the IBM PC and DEC Rainbow. drives to communications and format convention - like ELECTRONICS & WIRELESS WORLD MARCH 1985 49

www.americanradiohistory.com G.P.I.B.

GPIB control signals IEEE 728, BS6146 part 2 and but it also dictates what goes data bus not only carries data IEC 625-2 have only recently where on the bus. There may bus also address and status Signal Description appeared. be more than one controller on information at rates of up to On the brighter side, GPIB a bus but only one is allowed to 250kbyte/s (higher rates are DAV Data valid, talker tells signal functions are defined, act at a time. Controllers vary possible under certain circum- listener that data its which means that one should be from a dedicated piece of stances) . Incompatibilities available able to resolve compatibility apparatus with special software, between products from different NRFD Not ready for data, from problems by rewriting the in which case the user will need manufacturers and, unready listener - to NDAC Not data accepted, from programs used to control the know little of how the bus according to Tektronix even listener while getting data instruments. Because of these works, to a microcomputer with between different instruments IFC Interface clear, from incompatibilities, many GPIB a GPIB interface which the user from the same manufacturer - controller to set ali product manufacturers freely has to program in a high or low- arise through differences in the devices to a known state provide documentation and level language. form of the data. For example, ATN Attention, from controller application notes relating to In the most basic system some systems may use Ascii to alert bus devices their own protocols and data there may be just a talker and a and others hexadecimal -form before handshake of a formats. There are no active listener. At the other end of the data. The table gives some idea message on the data bus elements in the bus itself, i.e. scale, although the standard of what the bus control signals SRO Service request, from any are. device needing service all signals passing along the bus only allows for 15 devices to be are produced within the connected to the bus on a cable There are large-scale from the controller integrated circuits, such as the REN Remote enable, from instrument or a computer with of up to 20m, there are Texas 9914, which reduce the controller to put devices a GPIB controller, which makes products called bus extenders complexity of implementing under bus control the task easier. and multiplexers which share GPIB and are gradually bringing E01 End or identity, from out an allocation. Not all the price of both The bus down talker to indicate that devices connected to the bus instruments and controllers. current data byte is the There are three terms used to need be measuring instruments; Using such an i.c., the GPIB last one describe devices connected to there are converters, for say section of a computer need only the GPIB - talkers, listeners RS232 to GPIB, floppy -disc consist of three i.cs, two of and controllers. Instruments are drives and printers to mention which are bus drivers. Software either talkers or listeners or but a few. and the cost of instruments for both. Because these terms are Essentially, the bus carries use on the bus are the biggest normally associated with an eight -bit parallel data word, headaches for most. Finally, note that two types humans, you may find it a little three data -transfer control of connector are found on GPIB unfriendly that GPIB talkers signals and five interface instruments, a 24 -way type on and listeners do so to the bus management signals. All control 1EEE488-based equipment or a and not to the user. signals are at t.t.l. level and 25 -way type defined in the IEC A controller talks and listens active low. The bidirectional standard. GPIB Instruments Prices are given here only as a 160dB common mode rejection and millivoltmeter covering 10kHz to guide and should be checked with 0.01% accuracy. With the interface 1.2GHz and giving readings in mV, suppliers. Value-added tax is not included the basic price is £210. dBmV and dBm; a single or dual - included. Other models offer 3i -digit display channel microwattmeter for Adret Electronique make and liquid crystal display. Amplicon 100kHz-50GHz which stores several GPIB instruments for use in Electronics Ltd., Richmond Road, calibration data for up to eight telecommunications: two signal Brighton, East Sussex BN2 3RL. sensors; and an f.m./a.m. Datron's Autocal precision generators, models 730A and 740A, EWW212 modulation meter. Also available: a multimeters covering 300Hz-180MHz and Ando make instruments for use 1MHz automatic bridge and an 100kHz to 1.12GHz respectively; a in optical fibre communications. adaptor for interfacing any Boonton universal r.f. generator of high Model AQ -1301 is a light source digital meter to GPIB. Euro spectral purity for up to 1.3GHz which can be swept from 0.6 to 1.6 Electronics Ltd., Lancaster Gate with pulse modulation capability, micrometres and is intended for House, 319 Pinner Road, Harrow, for use with radionavigation measuring characteristics of optical Middlesex HAI. 4HF. EWW215 systems; a 15-200kHz standard transmission systems. There is a Brown-Boveri make a frequency receiver; a 2kHz-18GHz choice of three optical power meters microprocessor-controlled portable signal source attenuation calibrator, of differing sensitivities, all of them multimeter (model M2110-01) with` with a dynamic range of -130dBm suitable for normal or laser light. a 4l -digit liquid crystal display. It to +20dBm; and a programmable Other models include an optical has seven operating modes, voltage and current reference wavelength meter for measuring the including one for testing capacitors standard. Racal -Dana Instruments centre -wavelengths of emission between 10pF and 3mF; it handles Ltd., Duke Street, Windsor, devices, an optical fibre direct current measurements up to Berkshire SL4 1SB. EWW210 reflectometer (model AQ -1720), an 20A and on a.c. ranges it measures Aim Instruments offer at optical spectrum analyzer (AQ - true r.m.s. values. British Brown- present just one GPIB model, a 1417B) and two optical loss Boveri Ltd., Normelec Division, low -distortion sine -wave oscillator measurement systems. Aspen Grovelands House, Longford Road, covering 9Hz to 330kHz. The Electronics Ltd., 2-3 Kildare Close, Exhall, Coventry CV7 9ND. LD0501 (985) has ten non-volatile Eastcote, Ruislip, Middlesex HA4 EWW216 9UR. EWW213 memories, a quadrature output and Brüel & Kjter's catalogue lists a liquid crystal display. It can also Bird: the model 4381-832 RF some 16 instruments equipped with be controlled from an RS232 Power Analyst digital wattmeter is a GPIB interface and several others interface. Aim Instruments, Edison available with a GPIB interface from which can be connected via a Road Industrial Estate, St Ives, Aspen Electronics Ltd., 2-3 Kildare special adaptor. The instruments Huntingdon, Cambridgeshire PE17 Close, Eastcote Ruislip, Middlesex include audio spectrum analyzers, 4NF. EWW211 HA4 9UR. EW*214 fast Fourier transform analyzers, a Amplicon's 4Z digit panel meter Boonton produce several filter set, a digital graphics is claimed to be the first to have an instruments suitable for GPIB recorder, an X -Y plotter, a digital integral IEEE interface. Features of control. For radio frequencies, cassette recorder, a portable the model 87 include led display, there is an autoranging thermal printer and diagnostic 50 ELECTRONICS & WIRELESS WORLD MARCH 1985

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PERFECTION 1 Montgomery Place Irvine, Ayrshire KAl2 8PN The great thing about the IC -M5 is the Telex 777582 quick and easy access to its functions. (mark: attn IBS) This is made possible thanks to the 16 button keyboard entry to all international and U.S.A. channels, semi -duplex, memories, THE ENGINEERS Z80 memory scan and priority functions. Private channels can be easily installed. COMPUTER WITH This VHF 5 watt marine transceiver is water-resistant and boasts features found on IEEE 488 no other unit, they include: all U.K. channels plus ten weather channels (U.S.A. only), and ten owner -programmable memories with internal lithium memory backup. Three built-in scanning systems for memories, all channel and weather channel scanning. Dual watch enables you to simultaneously monitor channel 16 and communicate one other channel of your choice. Easy -to -read digital readout, day or night. Ready to go with the accessories needed to get you operational. The IC -M2 and M12 handheld marine transceivers will still be available. ICOM The World S Thanet Electronics Ltd. Suppliers or Radio Communication Equipment to the Ministry of Defence. 143 Reculver Road, Herne Bay, Kent, England. Tel(02273) 63859/63850. Telex 965179. CIRCLE 85 FOR FURTHER DETAILS.

TURN YOUR COMPUTER INTO A REAL TIME IMAGE PROCESSOR WITH THE IMAGE III FRAME STORE

* 2 x Z80 CPU's (4MHz) * 64K DYNAMIC RAM OVERSEAS.. PRICE * UP TO 32K EPROM AGENTS * FLOPPY DISK CONTROLLER FOR 3", 5" £1,990.00 Disk Drives REQUIRED % and 8 * 2 x RS232 SERIAL I/O CHANNELS * I/O MAPPED VIDEO GEN. 80 Cols. 24 Lines IMAGE Ill isahigh resolution Frame Store which can capture and display pictures * 4 x PARALLEL I/O CHANNELS in real time from any 625/525 line video source. Once captured in the 512 x 512 * PARALLEL KEYBOARD PORT frame memory, the computer can access the stored image for processing or (POWERED) manipulation. The store utilizes 6 bit A/D and D/A converters to give up.to 64 grey * IEEE 488 INTERFACE levels per pixel. A major feature of this store is that if a lower resolution picture is * HARDWARE REAL TIME CLOCK to e.g. for 256 x selected then the store can be partitioned store multiple pictures, * 2 x 8 BIT SWITCHES MAPPED) 256 resolution, four pictures can be stored. This allows the computer to compare (I/O two or more pictures captured from the same or different video sources. * MONITOR PROGRAM IN PROM * PROM BASED SOFTWARE AVAILABLE The IMAGE Ill Frame Store tarns your computer into a low cost image processing such as ASSEMBLER/EDITOR, and XTAL system and opens up a rartge of possibilities such as Robotic Vision, Medical BASIC WITH IEEE DRIVERS Imaging, Factory Inspection etc. Alternatively the store can be used in applica- The IBS 750 is an Quality Product designed for reliability tions where picture data is arriving slowly e.g. weather satellite transmissions, Industrial and ease of use. It is normally supplied fully -built and tested but is ultrasonic imaging, enabling the user to have a steady displaywithoutthe need for also available in a number of partially -built options. long persistence display devices. The Monitor PROM contains 22 user commands which will assist in IMAGE Ill is available for the IBM PC, Apple and BBC computers. The interface writing and de -bugging of the SBC's console and printer requirements by just opening or closing links on the PCB. The same card connects directly to the expansion ports of the computer and software is sup- configured version of CP/M 2.2 is available for various Disk sizes. plied which demonstrates the features of the store. A complete Development System and Desk Top Computer based The TV Picture Store Board used in IMAGE Ill was developed by British Telecom on this board is available with a variety of Disk Drive sizes and Research Laboratories and is manufactured under licence by Eltime Ltd. This board case styles to suit users requirements and environment. can be purchased separately for OEM applications. Tel (0294) 75000/73333

Unit 029, Maldon Industrial Estate, Fullhridge Maldon, Essex CM9 7LP 59500 ELTIME LTD Tel: 0621 ...... CIRCLE 14 FOR FURTHER DETAILS. CIRCLE 30 FOR FURTHER DETAILS.

ELECTRONICS & WIRELESS WORLD MARCH 1985 51

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AThis portable data logger from Microdata stores up to 100 input channels on a standard tape cartridge ultrasound equipment. Brüel & Clarke -Hess's wideband volt- to 32 cells) £7,340. Lyons Price is likely to be £1,800. Already Kjmr (U.K.) Ltd., Cross Lances ampere -watt meters provide true Instruments Ltd., Ware Road, available is E.D.A.'s GPIB interface Road, Hounslow, Middlesex TW2 r.m.s. measurements independent Hoddesdon, Hertfordshire EN11 for the Apple II computer (£250). 2AE. EWW217 of wave-shape and power factor. 9DX. EWW226 E.D.A. (Software) Ltd., 10 Victory Burleigh Instruments make a Model 255, the cheapest, costs Datron's Autocal digital Road, Chertsey, Surrey. EWW231 meter which can measure the £1,885 with GPIB interface. Lyons multimeters feature bus control of E.I.P. specialize in microwave wavelength of any c.w. laser Instruments Ltd., Ware Road, almost every function except mains test and measurement instruments. operating between 0.4 and 4 Hoddesdon, Hertfordshire EN11 on/off. Prices range from £1,095 to The model 928 is a combined micrometres. Lambda Photometrics 9DX. EWW222 about £3,000 according to the sweeper and microwave source Ltd., Lambda House, Batford Mill, Cushman make an automatic optional extras fitted. These meters covering 1-18GHz, with a c.r.t. Hertfordshire AL5 5BZ. test set for mobile radio equipment, can be calibrated in situ using display. Model 545 is a ECECHa.,peeWW218n, model CE6488. Racal -Dana Datron's two automatic calibrators, microprocessor -based 10Hz-18GHz make a GPIB-compatible Instruments Ltd. Duke Street, which are claimed to provide levels counter with 12 -digit led display; signal conditioning system which, Windsor, Berkshire SIA 1SB. of accuracy previously obtainable and model 548A is similar, but with they say, can improve test sysyems EWW223 only in temperature -controlled an upper limit of 110GHz. The and save the user money. The PSC- Datacapture offer a compact laboratories. The 4000 (d.c.) costs source locking counters model 575 8000 is of modular construction, portable time -related measurement from £8,495 and the 4200 (a.c.) (up to 18GHz) and model 578 (up with up to 12 channels per 19in. system. The Datablock DB4000 from £15,995. Datron Instruments to 110GHz) can convert any mainframe. Each channel has plug- accepts a variety of sensor inputs, Ltd., Hurricane Way, Norwich conventional swept -frequency signal in modules for interfacing to strain can memorise hundreds of Airport, Norwich NR6 6JB. source into a synthesizer. Also gauges, thermocouples or other thousands of measurements to an EWW227 available is the model 451 925MHz- sensors. CEC Instrumentation Ltd., accuracy of 0.025% and can store 18GHz pulse counter. Racal -Dana Lennox Road, Basingstoke, data indefinitely on plug-in DI -AN Microsystems provide Instruments Ltd., Duke Street, Hampshire RG22 4AW. EWW219 exchangeable memory boards. It through their DMS550 system a Windsor, Berkshire SL4 1SB. Chase offer a pair of high- can measure and display up to 16 way of interfacing GPIB controllers EWW232 performance receivers covering 25- inputs at once. Prices start at to sensors and actuators both digital Electronic Development 300MHz and 25-1000MHz, for £3,385, including GPIB interface and analogue. Data transfer is Corporation manufacture an a.c. applications such as field -strength and software. Datacapture 1984, 21 possible at up to 250kHz. A calibrator covering 10Hz to 111kHz measuring, interference measuring Bridge Street, Hemel Hempstead, mother -board accommodates the with amplitudes from 0.lmV to and radio monitoring. The sets can Hertfordshire HP1 1EG. EWW224 user -configurable i/o modules: 111V (model 4500, £7,245) and a there is a of be used as selective r.f. voltmeters, Datalab have developed a range range ten at present. companion d.c. calibrator (model even in the presence of strong r.f. of filters especially suited to high- DI -AN Microsystems Ltd., Mersey 520A, £3,410). Lyons Instruments fields. Accessories include dipole, speed data acquisition and House, Battersea Road, Heaton Ltd., Ware Road, Hoddesdon, log -periodic and biconical aerials. waveform analysis systems. The Mersey, Stockport, Cheshire SK4 Hertfordshire EN11 9DX. EWW233 3EA. EWW228 Chase also supply a controller for DLF-100 is a series of finite Exact Electronics produce a r.f.i. and e.m.c.-measuring impulse response decimating filters, Difa's Sicos signal conditioning 20MHz programmable pulse and equipment, model EC5000. This which the company say will make system is built up of modules such function generator with a very wide has a 6in. monochrome display new data acquisition architectures as programmable filters and selection of waveforms and monitor and one or two 3iin disc possible and will improve precision amplifiers. A choice of operating modes. It also has a self - drives. The operating system and performance of existing systems. filter characteristics is available and calibration facility and non-volatile Basic language are compatible with Also available is a range of the frame can house up to 64 memory capable of storing 20 the BBC Micro. Chase Electrics waveform recorders. Model 912 channels. If only two channels are complete front panel settings. Ltd., St Leonard's House, St (about £5,000 with GPIB interface) required, there is a lower -priced Racal -Dana Instruments Ltd., Duke Leonard's Road, London SW14 has two channels, a split timebase alternative in the PDF3700 (from Street, Windsor, Berkshire SIA 7LY. EWW220 mode, signal capture at up to £1,900). Telonic Instruments Ltd., 1SB. EWW234 Boyn Valley CIL produce a variety of 5MHz, a 4Kbyte memory, Road, Maidenhead, Farnell Instruments: items with instruments with GPIB capability. expansion possibilities and an Berkshire, SL6 4EG. EWW229 GPIB control include the low-cost The Multi-Monitor TA880 is a output to drive an X -Y plotter. Dolch make a series of GPIB- DTS-12B two -channel 12MHz voltmeter, millivolt source, Accessories are available. The controllable logic analyzers having digital storage oscilloscope (£980); temperature indicator, modular 2000 series offers up to 30 up to 64 channels and covering a programmable auto -ranging bench thermocouple simulator and strain channels with wide dynamic range frequencies to 300MHz. power supply providing more than indicator all rolled into one. Other and sampling rates of up to 50kHz: Accessories include a probe for 1kW at up to 60V and up to 50A models include multi -channel a -to -d prices depend on facilities, typical tracing and recording GPIB activity. (AP60/50, £1,700); auto -ranging converters with 12 and 16 bit systems costing £60,000 or more. Dolch Logic Instruments Ltd., signal generators for 10Hz to 1GHz accuracy (prices from £475), a Data Laboratories Ltd., 28 Wates Foresters House, 4 London Street, or 2GHz (from £4,300); the thermocouple converter, a multi- Surrey CR4 4HR. Andover, Hampshire SP10 2PA. SSG520 10-520MHz synthesized function control and measurement Wayy,Scham, EWW230 signal generator, designed interface and a GPIB bus analyzer. Data Proof produce a scanner for E.D.A. expect to launch in May especially for maintenance of mobile CIL also offer a GPIB interface card comparing standard cells using the or June a 10Mbyte Winchester disc communications equipment (from for the Apple computer (£130). CIL method recommended by the U.S. drive which will allow any computer £3,000); and a test set for radio Microsystems Ltd., Decoy Road, National Bureau of Standards. with a GPIB interface to access the transmitters of up to 100W output Worthing, Sussex BN14 8ND. Model 160A (for up to 16 cells) disc without the need for a separate (model TTS20, from about EWW221 costs £4,280 and model 320A (up interface card or operating system. £3,900). Farnell Instruments Ltd., 52 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com THE ANSWER TO LOW COST 1 EEE 488 BUS CONTROL

The EDA Instrument Controller Prices: combines low cost with flexibility. EDA Instrument Controller Based on the Apple Ile £1950.00+VAT EDAIC is fitted computer, the 5mByte Winchester Disk p.o.a. as standard with an IEEE 488 bus controller, clock/ A3 Plotter p.o.a. calendar, 80 column x 24 IEEE 488 Controller Card line VDU, 128k user RAM, (Apple BASIC version) floppy disk storage, and £250.00 + VAT 80 column printer. Optional extras include (SSM PASCAL version) 5mByte Winchester disk £350.00 + VAT drive, A3 plotter, and a Available now from: range of parallel and serial interface ports. Programming is in E.D. A. BASIC or PASCAL and the IEEE 488 bus can be (Software) Ltd. controlled with simple to use 10 Victory Road, high level commands. Chertsey, The EDAIC is ideal for use in Surrey KT16 8BL factories and laboratories for test Telephone: 09328 63758 and process control work. Trade inquiries welcome.

CIRCLE 86 FOR FURTHER DETAILS.

The CM1600 Measurement KEMO LTD., 12 GOODWOOD PARADE ELMERS END, BECKENHAM. KENT BR3 30Z and Control Interface TEL: 01-658 3838 TX: 8953189 KEMO G from IMS Electronics

AntiAlias Filters

Unique construction allows flexibility Four module positions, each with four channels Each module may be selected from an ever increasing list including: ± 10 volt outputs, 16 bit resolution ± 10V, 1V, 100 mV (Software Selectable) inputs, 16 bit resolution Thermocouple inputs (linearised) Single pole change over relays (mains rated) CHOICE OF IEEE -488 or RS 232C INTERFACE Z80 MICROPROCESSOR BASED Pulse Corrected Anti -Alias Modular Optional extras include: Dot matrix panel printer (as illustrated) and Multi -Channel System Filters 32K RAM for assistance in data acquisition NII ¡MS Electronics

NILNII II ! Unit R6, Riverside Industrial Estate, Bridge Road, Agents in: Australia, Austria, Belgulm, Canada, Finland, France, Germany, West Sussex BN17 5DF Greece, Holland, Hong Kong, Ireland, Italy, Japan, New Zealand, Norway. J Littlehampton, Scotland, South Africa, Sweden, Switzerland, Taiwan. SALES TELEPHONE (0903) 723492

CIRCLE 117 FOR FURTHER DETAILS. CIRCI.E 87 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MARCH 1985 5:3

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Sandbeck Way, Wetherby, West GPIB interface. Global Specialties event counter for £350. Harlyn bus interface for programmable Yorkshire LS22 4DH. EWW235 Corporation, Shire Hill Industrial Automation (Congleton) Ltd., 27 power supplies. Amplicon Fluke's large catalogue includes Estate, Saffron Walden, Essex North Street, Congleton, Cheshire Electronics, Ltd., Richmond Road, some 80 instruments with GPIB CB11 3AQ. EWW240 CW12 11IF. EWW244 Brighton, East Sussex BN2 3RL. control. Among these are power Gould have a range of digital Hendry Electronics specialize in EWW248 sources, thermometers, signal storage oscilloscopes with prices programmable variable power Infratek produce a three-phase generators, counters, calibrators, beginning at £2,950. For this you supplies. Units in their range can volt -ampere -watt meter which gives p.c.b. testers, data loggers, get a dual -trace oscilloscope (model handle maximum loads of up to true r.m.s. measurements from 0 instrument controllers, disc drives, 4035) with 20MHz bandwidth, a 1K 2000VA. Prices begin at £473 for a to 10kHz to an accuracy of 0.5%. printers and an X -Y plotter. A word store on each channel, a basic plug-in 30VA card, with GPIB Ranging is automatic or manual and recent addition to the range is the plotter interface and a cursor control costing £591 extra for a extends to 1kV, 30A and 90kVA 8840A digital multimeter (from measurement facility with single -channel interface. There is (optional accessories push the £735 with GPIB interface fitted): alphanumeric readout of time and also a high -power mil. spec. range. current limit even further). Seltek this has a 52 -digit vacuum voltage. An optional keypad (£340) Hendry Electronics Ltd., 2 Fitzalan Instruments Ltd., The Old Pied fluorescent display, fast auto - allows further manipulation of Road, Arundel, West Sussex BN18 Bull, High Street, Stanstead ranging and a built-in self -test stored traces. At £4,995 is model 9JS. EWW245 Abbotts, Hertfordshire SG12 8AB. routine. Fluke (GB) Ltd., Colonial 5110 which gives 100MHz Hewlett-Packard invented the EWW249 Way, Watford, Hertfordshire WD2 bandwidth, keyboard menu control GPIB (or rather, HPIB) and their 4TT. EWW236 Intepro Systems' instruments and battery -backed memory for instrumentation range is accordingly for the automatic testing of Frequency Devices' model 9016 eight panel settings and 16 all -embracing. Their 688 -page regulated power supplies programmable multi -channel filter waveforms. These instruments can catalogue lists more than 180 incorporate modular hardware and system is a 19in. enclosure with a act as talkers as well as listeners instruments with bus capability, software and can be configured and vacuum fluorescent digital display and can transmit waveforms to the plus 27 ready-made HPIB reconfigured easily by the user. and space for up to 16 filter cards. bus for analysis or for data measurement systems - Units are available to suit power At present cards are available in a acquisition. Gould Instruments applications of which include data supplies of 100W to 1kW and more. choice of three low-pass transfer Ltd., 2-8 Roebuck Road, Hainault, logging, data acquisition and Omnitest Ltd., Highcliffe House, functions. Price is £4,690. Lyons Ilford, Essex IG6 3UE. EWW241 control, network analysis, spectrum 411-413 Lymington Road, Instruments Ltd., Ware Road, Guildline make a digital platinum analysis, frequency stability Highcliffe, Christchurch, Dorset Hoddesdon, Hertfordshire EN11 resistance thermometer covering measurement, signal generator BH23 5EN. EWW250 9DX. EWW237 -200°C to +240°C with a resolution calibration, transceiver testing, Interface Technology make a GenHad produce a range of of 0.001° and an accuracy of 0.01°C. testing of circuits and components, automatic test equipment, among pressure recording and range of digital testing equipment, The model 9540 costs £2,760. A among which which are systems for board testing digital wattmeter, model 7200, telecommunications network is the model 488 IEEE bus monitor and controller (around and for examining and sorting gives direct digital measurement of surveillance. Hewlett-Packard Ltd., £6200). This can be triggered on a digital and linear components. power, voltage, current and energy, Nine Mile Ride, Easthamstead, GenRad Ltd., Norreys Drive, with 50 Wokingham, Berkshire RG11 3LL. specific device address and can p.p.m. accuracy at all record up to 511 Maidenhead, Berkshire SL6 4BP. power levels, for £22,870. Lyons EWW246 transactions, EWW238 including data and control line Instruments Ltd., Ware Road, Hitachi's range of oscilloscopes status. Microsystem Services, P.O. Hoddesdon, Hertfordshire EN11 includes the VC -6041, which costs Giga Instrumentation Box 37, Lincoln Road, Cressex manufacture a pair of 1-18GHz 9DX. EWW242 £4,897 with GPIB interface and can Industrial store 40MHz waveforms with its Estate, High Wycombe, microwave generators (models Gulton's Computrak 6100 Buckinghamshire HP12 3)j. GR1100/1300) for testing radar programmable recorder plots as two 4000 -word digital storage EWW251 sets. The YIG tuned oscillator can many as six channels at once on its channels. A time -axis averaging Itronic-Fuchs manufacture a be set to within 100kHz and the built-in thermal printer; adding function allows the user to average - internal pulse modulator provides chart out noise on input signals. An GPIB-controlled pneumatic switch grids, time and text system. Eight switch modules are 60dB of carrier suppression. Other annotations automatically. A data instrument with a more specialized housed in a compact unit, providing gives a purpose is the MF -68 automatic products are the GU1200/1300 summary print-out up to 64 lines of control. Expansion signal generators for 10MHz- permanent record of the telecomparator system. Linked to a system to 256 lines is possible. A typical 26.5GHz, also featuring a YIG configuration. Also available are television camera and an optical microscope, this uses the tv signal application is the testing of oscillator, and the GP2000 three free-standing thermal computer keyboards programmable sweep generator for printers. Gulton Ltd., Maple to make line -width measurements using the range. Racal -Dana Works, Old Shoreham Road, Hove, on i.c. wafers and masks, magnetic pneumatically -controlled artificial same fingers. Omnitest Highcliffe Instruments Ltd., Duke Street, East Sussex BN3 7EY. EWW243 heads and so on. Hitachi Denshi Ltd., (U.K.) Ltd., Garrick Industrial House, 411-413 Lymington Road Windsor, Berkshire SIA 1SB. Harlyn Automation manufacture Highcliffe, Christchurch, EWW239 Centre, Garrick Road, London NW9 Dorset instrumentation and control 9AP. EWW247 BH23 5EN. EWW252 Global Specialties make a nine - peripherals for use in automated digit, two -channel 225MHz data logging. The 3700 series ICS offer a speech synthesizer. Iwatsu's range includes the SAS - computing counter -timer with a MAPS data logger system includes The standard vocabulary includes 8130 and SM2100B high-speed 1.2GHz prescaler (model 6007/T); three mainframes (all with integral nearly 300 entries which are spoken waveform analyzers, with sampling an eight -digit counter -timer with GPIB interface) and an extensive in what the makers describe as a heads available for frequencies up to direct input to 520MHz (model choice of plug-in modules. The R6B natural masculine voice. Manual 12.4GHz; the SS5802 triple -trace 6006T); a universal 4k -digit mainframe, a 19in rack -mountable and automatic controls are provided 10MHz digital storage oscilloscope; wattmeter (model UDW4501) for up unit for up to six modules, with for editing and formatting the a 100MHz storage oscilloscope (TS - to 50kHz, with a dynamic range of 1MHz clock, costs £650. Modules spoken messages. Other products 8123) incorporating a special scan 100nW to 7.5kW; and a family of include a 10 -channel 2 -pole scanner are bus switches and expanders and converter tube and having low-cost true-r.m.s. digital with reed relays at around £295, a variety of bus input and output equivalent clock rate of 25GHz; the multimeters. All are available with and an eight -decade battery -backed modules; for example, a low-cost SC7501 12 -channel data -logging This waveform acquisition and processing package from Tektronix is aimed at applications such as fibre optic testing

www.americanradiohistory.com CARD HA ' 111

Our cards take the gamble out of systems integration! Take a look at our cards for LSI-II Q Bus, VME Bus, DEC Unibus,

STD Bus, IEEE 488 Bus, VERSA Bus, Multibus, IBM PC and Digital LSI-II SERIAL I/O Rainbow. Model 304 four channel serial I/O port for inter- You'll find we give more value or more functions, or save you facing Q Bus to asynchronous serial data chan- money or space in your backplane. nels. A direct replacement for the DLVI 1-J, totally software compatible. Each port may be indepen- Our technical support is by people who really know computer dently configured for RS232C, RS422 or RS423, at buses, our sales and service engineers are factory trained to know nine jumper selectable data rates from 150 to 38.4K baud generated by an on board clock. An our products. external dock may be provided for up to 250K baud data rate. Whether its serial I/O, analog I/O, digital I/O, comms, bubble Four level vector interrupt structure capability for memory, system fault analysis or bus conversion, our board level mutt user environments with the possibility to con- products you more, to help you build a better system. figure channel four as the system consul. All this give on a standard 8.9" x 52" card with despatch the For the best deal in cards call us, we'll see that YOU WIN. same day you order.

Amplicon Electronics Limited Richmond Road Brighton East Sussex BN2 3RL UK AY/ \ CIRCLE 94 FOR FURTHER DETAILS: Tel. Brighton (0273) 608331 Telex: 877470 AMPCON G.

www.americanradiohistory.com 4 aLi= THE CHOICE

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TA 880 DTR 1000 .SGA 1100

Multi monitor IEEE RS232 for Up to 10 sec. at 20 KHz audio " Multi purpose signal conditioning temperature, voltage, strain transient recorder for analysis and system for strain and temperature indicator and simulator playback - IEEE RS232 tacle no 99 measurements Circle no 102 circle no 9t

DTR 1681 DTR 1680 DTR 1682 IEEE RS232 ' and digital voltmeter Dual IEEE and RS232 digital Front panel programmable 16K s with 16K BASIC option for AC and voltmeter with 16K BASIC option BASIC 64K RAM IEEE and RS232 + DC to 0.01 % , clrcie no 97 for AC and DC to ± 0.01 % digital voltmeter circle nó 103 ` circle. no 100

POWER ON

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TALK A

CIL Electronics Ltd Worthing 204646 .1,

MFI 1010 DTR 3000 DTR 2000 Programmed to become a Signal processing computer with .Pocket computer programmable' specified instrument or system via data acquisition and audio large 'with various industrial RS232 for industry circle no 98 scale storage circle np 101 datalogging applications. 104 . Electronics moto Decoy Road, Worthing, Sussex BN 14 8ND Telex: 87515 WISCO G CIL CIL Tel Worthing (0903) 204646

P www.americanradiohistory.com

FOR THEFUTURE...

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PCI6380 ' PCI 1480 PCI 2080

Intelligent IEEE or RS232 interlace . . High speed 16 bit A -D ccnversion 8 channel relay closure unit to with 8 analogue inputs, ,4 outputs, :for computers with IEEE or RS232 operate from the IEEE or RS232 4 relay contacts circle ne 105 links círc,e no 108 links r irc le no 1 1 1

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PCI 3080; PCI 1002 PCI 1000 8 channel D -A converter designed 12.channel IEEE compatible Low cost 16 channel 12 bit IEEE , to opérate from the IEEE or RS232 thermocouple converter based on analogue to digital converter circle no : links circle no 106 the PCf 1000 circe no 109 112

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' IEEE -488 Bus analyzer record/ . High speed (20µS) large storage Low cost multifunction interfaces playback facilities and transparent intelligent 16 bit A -D for IEEE and for Commodore 20 to 80 series to BUS urr'e nr) 14)7 RS232 circle no 110 and SX64 circle no 113

wucrosystems itt. ' Decoy Road, Worthing. Sussex BN 14 8ND Telex: 8751 5 WISCO G ATT CIL cri Tel: Worming (0903) 2`10474

www.americanradiohistory.com VERSATILE INTERFACE BOARD FOR USE WITH OUR 6809 OR 6502 CONTROLLERS

Program in BBC BASIC, FORTH, PASCAL

100 Digital I/O Lines Real Time Calendar Clock RS422/423 Serial Channel Centronics Printer Port

8 Programmable Timers Full Technical Support 6502 and 6809 Development Systems Add: High Resolution colour graphics 12 Bit ADC IEEE Talker listener controller

Eprom Programmer 44a Hobson Street Cambridge Industrial Racking System Cambridge C81 IIYI. Microprocessor (0223) 324141 Systems Limited

CIRCLE 79 FOR FURTHER DETAILS.

SE 2650 BUS CONTROLLER THE IEEE 488 BUS CONTROLLER MEETS ALL THE DEMANDS OF TODAY'S MEASUREMENT AND CONTROL SYSTEMS - PLUS DESK TOP COMPUTING POWER AS AN ADDED BONUS. JUMP ON THE IEEE BUS

SE 2750 INTERFACE CONVERTER A COMPLETE SOLUTION TO YOUR INTERFACING PROBLEMS BETWEEN THE IEEE BUS, SERIAL, 8/16 BIT PARALLEL AND BCD DATA SYSTEMS.

Phone or send for details of the range of IEEE Bus compatible instruments from THORN EMI Datatech:- SE 2650 IEEE Bus Controller SE 2450 Frequency Response Analyser SE 1700 Programmable Digital Filter System THORN EMI SE 2550/60 Transient Recorders E=113 SE 2750 Interface Converter Datatech THORN EMI Datatech Ltd., SE 3000/ Instrumentation Division, Spur Road, Feltham, Middlesex, TW14 OTD, England 7000/9000 - Instrumentation Tape Recorders Telephone 01-8901477 Telex: 23995 SE 6400 - Galvanometric Recorders A THORN EMI company CIRCLE 65 FOR FURTHER DETAILS.

ELECTRONICS & WIRELESS WORLD MARCH 1985

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multimeter with built-in thermal been added. Marconi Instruments printer; and an A3 -size graphics Ltd., Longacres, St Albans, plotter (SR6602) with one pen or Hertfordshire AL4 OJN. EWW258 six. STC Instrument Services, Microdata offer a variety of data Edinburgh Way, Harlow, Essex acquisition and logging systems. CM20 2DF. EWW253 These can be housed in racks or Keithley offer a large choice of laboratory instrument cabinets, in GPIB instruments: among them are portable cases or in sealed suitcase - the model 195A six -function style enclosures for harsh programmable multimeter (ranges environments. Plug-in input cards include temperature in °F or °C) at accept signals from any commonly - £895; a programmable electrometer used analogue or digital transducer. and voltage source which can U . to 100 input channels are handle over 14 decades of current ossi , with some models. measurements and 17 of resistance Microd. to Ltd., Monitor House, (model 617); a nanovoltmeter Station ' oad, Radlett, Hertfordshire (model 181, £3,395), an WD7 :JX. EWW259 autoranging picoammeter (485, £1,020) and a microvolt multimeter MS (Mess + System Technik) (197, upwards of £700); a multi- produce a comprehensive system Testing mobile radio equipment with intruments by Racal -Dana function programmable current and for data acquisition, logging and process control. The ADP65 is voltage source which can source or recorder (PM4202, £740); an eight - have a full range of capable of handling 1000 Racal -Dana sink up to 100W (model 228); the analogue pen intelligent plotter (PM8151, GPIB components, which currently and 320 bitwise digital inputs, 30 705 and 706 system scanners with from £3,255); and a programmable include and 5z -digit multimeters; analogue and 160 digital outputs 4 50 and 100 -channel capacity and a power supply (PM1367, £905). Pye a 6z true r.m.s. a.c. plus 100 counter channels. Also -digit range of seven switching cards; and Unicam Ltd., York Street, measurement system; a 10kHz- available: the MDP82 series of the DAS Series 500 workstation for Cambridge CB1 2PX. EWW264 2GHz r.f. level meter; counter - data acquisition and control. signal and data i/o modules, an timers frequencies up to 3GHz, intelligent data recorder using Photodyne produce a fibre optic for Keithley Instruments Ltd., 1 multimeter and other fibre -probing some computing versions among Boulton Road, Reading, Berkshire standard audio cassettes and a high- them; r.f. generators covering speed cassette recorder capable of instruments. Several can be RG2 ONL. EWW254 interfaced to the GPIB through a 10kHz-104MHz or 3GHz; 48 - data rates up to 9600baud. Seltek channel spectrum analyzers; Kemo claim to offer the widest Instruments Ltd., The Old Pied special adapter. Lambda range of variable filters Photometrics Ltd., Lambda House, function and pulse generators; a Bull, High Street, Stanstead timing generator with real-time manufactured in Europe, with cut- Abbotts, Hertfordshire SG12 8AB. Batford Mill, Harpenden, clock; a of off frequencies between 0.001Hz EWW260 Hertfordshire AL5 5BZ. EWW265 series switching systems and 1MHz and bandpass response with driver and relay modules National Instruments specialize Photon Kinetics manufacture an to down to d.c. In most instruments automatic optical fibre analysis covering signal levels up 1kW each filter channel may be switched in computer-to-GPIB interfaces. and frequencies to 18GHz; a GPIB Cards and software are available for system (model FOA-2000) for into either high-pass or low-pass production and research. Lambda analyzer; and two 20 -column the IBM p.c. and DEC Rainbow, for -plotters, one with a mode. Many models are now Photometrics Ltd., Lambda House, thermal printer available with Cauer response for VME bus, Multibus, S-100, STD built-in clock. Racal -Dana and SBX buses and for DEC Q -bus Batford Mill, Harpenden, Duke Street, anti-aliasing applications in digital Hertfordshire AL5 5BZ. EWW266 Instruments Ltd., systems. Kemo Ltd., 9-12 and Unibus. The company also Windsor, Berkshire SIA 1SB. End, makes a GPIB tester, controller and PPM make some versatile EWW268 Goodwood Parade, Elmers for calibration, Beckenham, Kent BR3 3QZ. extenders. Amplicon Electronics switching systems data logging and process control. Rohde & Schwarz issue a EWW255 Ltd., Richmond Road, Brighton, measuring equipment catalogue East Sussex BN2 3RL. EWW261 These can be supplied as individual Kikusui's products include units or as complete systems. Bus which this year runs to over 430 storage oscilloscopes, Norma Messtechnik: products commands can be executed pages and includes signal programmable a.t.e. power sources include a 120MHz five -mode immediately or held as stored generators for frequencies up to and high -reliability power supplies. counter (D3655) and the System sequences. Chassis units are fitted 2.7GHz, test receivers and Oscilloscope prices begin at around 4000 family, comprising a precisions with modules selected from a wide modulation analyzers, £1,700 (including GPIB interface). digital multimeter, a true r.m.s. range of input and output devices. radiotelephone test sets, a set-up The DSS6522 two -channel model multimeter, a twin channel meter, a Software is available too. The for testing r.f. cables, r.f. step (£2,845), with a conversion speed precision wattmeter and a company also imports instruments attenuators, sweep generators, of 500ns, offers post -storage metallized -paper data printer with by Rotek, Ballantine and Valhalla, vector and network analyzers, logic expansion, an analogue X -Y output built-in timer. STC Instrument some of which it incorporates into analyzers, a group -delay measuring and a four -trace display. Telonic Services, Edinburgh Way, Harlow, its own systems. A typical set, meters of all kinds, relay Instruments Ltd., Boyn Valley Essex CM20 2DF. EWW262 automatic calibration set-up costs matrices for audio and r.f., a digital Road, Maidenhead, Berkshire SL6 Panasonic Industrial's principal £15,000 to £20,000. PPM Ltd., thermometer, a temperature a 4EG. EWW256 GPIB products are a 50MHz dual - Hermitage Road, St John's, Woking, controller, dot-matrix printer and LeCroy Research specialize in trace storage oscilloscope with Surrey GU21 1TZ. EWW267 a 16-function pneumatic interface. instruments for use in scientific linear interpolation, a yes/no EWW267 Rohde & Schwarz U.K. Ltd., research, in high-energy physics decision mode and a 2K memory especially. Available in modular (model VP -5730P), a fast Fourier Fluke's 8840A autoranging multimeter form, these units include fast data transform analyzer covering 0- loggers, amplifiers, triggering units, 40kHz and with a data memory of memory modules and transient 64Kwords (VS-331OP) and a 32 - waveform recorders capable of channel logic analyzer for sampling at up to 200 million microprocessor development, with samples per second. GPIB software clock speeds of up to 20MHz or is available. LeCroy Research 100MHz (VP -3620P and VP - Systems Ltd., Elms Court, Botley, 3662P). There are two graphics Oxford 0X2 9LP. EWW257 plotters: a six-colour A4 -size model Marconi Instruments. Products (VP -6801P40) and an eight -colour from Marconi with GPIB A3 version with a plotting speed of compatibility as standard or as an 450mm/s (VP -6802). Panasonic option are the following: a.m./ Industrial U.K. Ltd., 280-290 Bath f.m. r.f. generators for up to Road, Slough, Berkshire SL1 6JG. 1040MHz; a modulation meter for EWW263 up to 2GHz (model 2305); a radio Philips have an extensive range communication test set (model of GPIB instruments. Examples are 2955); four d.f.ms for frequencies timers, counters and r.f. up to 2GHz; a 10Hz-20GHz synthesizers for frequencies up to microwave counter with 0.1Hz 1GHz; an l.f. synthesizer (PM5190, resolution (model 2440); several £1,495); automatic digital items of p.c.m. test equipment; a multimeters (from £495 for the 4Z true r.m.s. voltmeter; and the 6500 digit PM2519/51); storage automatic microwave amplitude oscilloscopes (from £3,250 for the analyzer, to which new firmware PM3305C); a video generator and hardware enhancements have (PM5549); a digital cassette ELECTRONICS & WIRELESS WORLD MARCH 1985

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Technical Projects manufacture compare facilities. The 10MHz a versatile test set for rapid audio version is priced very competitively measurements. The 401D, which is at £395 plus £45 for the LC -03 aimed especially at the broadcast GPIB connector. Thurlby industry, measures level, noise, Electronics Ltd., New Road, St frequency, harmonic distortion and Ives, Huntingdon, Cambridgeshire spurious signals and there are add- PE17 4BG. EWW279 ons for phase measurement, rumble, wow and flutter and so on. Tri -Phenix manufacture a Display is on a fast -acting analogue programmable pulse generator peak programme meter. The offering repetition rates of up to optional GPIB interface controls all 20MHz and pulse widths down to front -panel fuunctions and provides 100ps. Price is £5,755. Also a digital output of the analogue available is a radar range simulator meter reading. Technical Projects for testing radar systems, model Ltd., Unit 2, Samuel White's PX219, at £9,855: this generates a Industrial Estate, Medina Road, return pulse capable of being The PM33O5 35MHz storage oscilloscope from Philips Cowes, Isle of Wight PO3 7LP. dynamically controlled to simulate EWW275 movement of the target. Lyons Instruments Ltd., Ware Road, Roebuck Road, Chessington, Surrey cepstrum analysis function. A data Tektronix: this manufacturer's Hoddesdon, Hertfordshire EN11 KT9 1LP. EWW269 logger, the Orion Delta 353OD, can GPIB range is very broad, with 9DX. EWW280 Scientific Atlanta have mn eight tasks with different levels components or ready -packaged introduced a signal analyzer (model of priority, handles up to 200 systems covering virtually every Wandel & Goltermann describe their large range of instruments for SD380) based on a mainframe channels (600 with slaves) and has need in testing, measurement or which accomodates expansion up to a powerful data processing ability. signal acquisition. A special feature the telecommunications industry in four channels and options such as The 4040 communications test set is consistency of command and data a catalogue of nearly 400 pages. data storage on 3zin. disc, speed is designed to meet all formats to make configuring and GPIB-compatible units include compensation for easy radiotelephone test requirements debugging simpler. One recent signal generators, level meters and interpretation of machine from audio to u.h.f. For radio addition is the TM5000 family, built spectrum and network analyzers; signatures. Features include real- testing and surveillance monitoring around two mainframes which can sets for measuring noise and time digital zoom, 3-D cascaded the Minilock measuring receiver can be fitted with any of seven distortion on radio links and waterfall display. Scientific Atlanta sweep and measure in the range intruments - counter -timers, a satellite systems; a data line test Ltd., Horton Manor, Stanwell 10kHz to 1GHz. Also in the range multimeter, a function generator set; p.c.m. digital signal Road, Horton, Slough SL3 9PA. are storage oscilloscopes, signal and so on. For setting up a system generators, analysers and test sets; EWW270 generators, a five -colour plotter and the EZ-Test software generator a harmonic analyzer for a.c. power a p.c.m. data transmission test set. package (about £1,000) enables the lines; and a remote switching Siemens manufacture a large Solartron Instruments, Victoria user quickly to create his own test system for frequencies up to family of instruments: a choice of Road, Farnborough, Hampshire software without having to learn a 160MHz. W & G Instruments Ltd., three multimeters and four power GU14 7PW. EWW272 special programming language. Progress House, 412 Greenford meters, pulse and function Systron-Donner's extensive Tektronix U.K. Ltd., P.O. Box 69, Road, Greenford, Middlesex UB6 generators, a generator-comparator range of instruments includes many Harpenden, Hertfordshire AL5 9AH. EWW281 for waveform curves storing up to with GPIB control as standard or as 4UP. EWW276 512 X 1024 a digital word Wavetek: most items in the points, an option. Among these are a Telonic-Berkeley have recently generator/comparator operating at current range are GPIB-compatible. modular optical communications introduced their TCD series tunable Examples are spectrum analyzers up to 2MHz, transient recorders system capable of handling video, bandpass filters. These are available with up to 64 channels, two with up to four channels, one of an MSF-synchronized clock, in three or five section versions them with built-in disc storage and frequency counters, a data line counter -timers and signal covering any one octave in the analyzer for telephony, a fibre -optic even an integral word -processor; generators covering frequencies range 32MHz to 3GHz. Telonic function and waveform generators reflectometer for locating fibre from 100Hz or so to 26GHz, pulse Instruments Ltd., Boyn Valley breaks and measuring the loss of for frequencies up to 50MHz; a.m./ generators, waveform analyzers and Road, Maidenhead, Berkshire SL6 f.m. r.f. generators; signal splices, d.c. voltage calibrators and programmable power supplies for 4EG. EWW277 programmable power supplies, a processing filters; signal switchers laboratory or stystems applications. Thom EMI Datatech make for up to 26.5GHz; microwave 30 -channel chart recorder, two X -Y Systron-Donner Ltd., St Mary's plotters and a thermal printer. several GPIB-compatible generators and measurement Road, Leamington Spa, instruments: a frequency response systems. Wavetek Electronics Ltd., Siemens Ltd., Windmill Road, Warwickshire CV3 1QN. EWW273 Sunbury -on -Thames, Middlesex analyzer (model SE2450) with a Tag Lane, Reading, Berkshire TW16 7HS. EWW271 Takeda Riken produce a range graphics option giving Nicholls, RG10 9LT. EWW282 of spectrum analyzers, from fast Nyquist or Bode plots on the Solartron make many GPIB Fourier transform analyzers for screen; a programmable transient Wayne Kerr manufacture several instruments. Digital multimeters acoustic and servo -system recording system (BE256) with a GPIB-controllable instruments for and precision voltmeters are applications to portable r.f. choice of memory sizes and testing components. The 4210 available with displays of up to 8Z analyzers covering frequencies up to sampling rates of up to 50MHz; an automatic LCR meter, with a basic digits. A logic analyzer (7610 20GHz. Also available are a floppy - eight -channel transient recorder accuracy of 0.1%, has percentage - series) has up to 48 channels with a disc digital data recorder, some with built-in screen display and deviation and binning facilities for 1Kbit memory for each, multiple microwave frequency counters and menu control (SE2550); and a automatic component grading, is timebases and the option of a signal generators for audio and signal conditioner (SE1700) with a able to polarize capacitors and can 400MHz input module. The model radio frequencies. Chase Electrics capacity of up to 256 channels. A identify the type of component 1200 signal processor is an Ltd, St Leonard's House, St pair of converter units make it plugged into it. The B905 autorrfatic advanced spectrum analyzer offering Leonard's Road, London SW14 possible to link GPIB to other precision bridge has auto -ranging, a logarithmic display format and a 7LY. EWW274 interface systems (SE2750) or to auto -trimming and displays results analogue signals (2A-488). Thorn on two five -digit l.c.ds. The 6425 precision component analyzer has PPM's model 8000 EMI Datatech Ltd., Spur Road, Feltham, Middlesex TW14 OTD. six -figure resolution and features a bus switching system EWW278 display screen with software - labelled function for Thurlby Electronics are to keys use when manual control is required. Wayne launch in April a range of programmable bench Kerr Instruments Ltd., Durban power Road, Bognor Regis, Sussex supplies with high -resolution PO22 9RL. EWW283 control: prices start at £395 for a 0- 30V, 0-2A supply. Already available Zelmtel produce a range of is a digital multimeter with systems for production testing of computing and data storage analogue and digital printed circuit functions, model 1905a, which with boards. Two of these, the 810 and IEEE interface costs £495. The the low-cost 310, can be enhanced IEEE bus itself can be examined by interfacing to GPIB instruments with Thurlby's LA-160 logic which then have access to the analyzer, which is usable with any systems' test points. Zehntel Ltd., conventional oscilloscope, comes Sentry House, 500 Avebury with 16 or 32 data channels and has Boulevard, Saxon Gate West, a 2000 word data acquisition Central Milton Keynes MK9 2NJ. memory with powerful search -and - EWW284 60 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com CIRCUIT IDEAS

VMOS squelch for pulse receivers This circuit uses the baseband p.p.m. (pulse-position modulation) output of a battery - powered v.h.f. a.m. telecommand receiver to switch on high current post -detector stages. Design requirements call for fast attack on receipt of the first 5Oms pulse in a five -bit sequence, followed by a hold ime of at least 1.5s to permit mmand activation. Using a cmos op-amp with buffer transistor gives low Capacitor C,, isolated from If D, is replaced by a short- standby current drain while the gate by D, during turn on, circuit, attack time is increased allowing up to 25OmA to be is charged towards the supply to around 2.4ms. In this case a switched. Time between a high rail through R2 aid D, for the lower drive -pulse slew rate can output from the comparator and pulse duration. When the be tolerated so the op -amp the buffer transistor switching comparator output goes low at quiescent current may be on is determined by R, and gate the end of a received pulse, C, reduced to 10µA for low -power capacitance of the transistor. A discharges through R, and D,, applications. fully -on gate threshold of 2.5V with the time constant R,C, N.E. Evans and gate capacitance of 10OpF determining time elapsed before Ulster Polytechnic give an attack time of O.13ms. load power dowr (around 1.8s). Co. Antrim

Bit -rate

24576 MHz generator

Originally designed for use with 470 470 a 6850 a.c.i.a., this circuit provides a cheap programmable bit -rate generator for most uarts with X16 or X64 clock inputs.

1/2 74LS393 Two four -bit counters in the LS393 are cascaded to form an 3 [KA Q eight -bit counter for dividing the crystal frequency down to 5 those shown in the table. The [LA Q0 seven lowest frequencies from the counter are fed to the LS151 eight -input data selector whose D- input may be used for 3 11 an alternative clock signal. Data CK8 select inputs of this i.c. can

9 either be connected to switches to a computer i/o port for 2 or CLRB software control of the data rate. OV 1/274LS393 P.J. Griffiths i 4 3 2 15 14 Uppingham 07 Do Leicestershire 74 LS151 Inputs Frequency (Hz) A B C W S C B A f/1 f/16 f/64 11 10 9 5 I6 7

0 0 o 9600 600 150 B OV 0 0 19.2k 1200 300 1 600 C 0 o 38.4k 2400 Rate select inputs 0 1 76.8k 4800 1200 To uart clock inpc t 1 0 o 153.6k 9600 2400 1 0 307.2k 19.2k 4800

1 1 o 614.4k 38.4k 9600 1 1 external clock

ELECTRONICS & WIRELESS WORLD MARCH 1985 61

www.americanradiohistory.com CIRCUIT IDEAS

From ilo port 4-5V RD MI LORO RFSH NMI address decoder ICta 74 LS138 DO -1 l..7 CK1 i D3 F8 J Y7 TRIG IC2 IC4a IC4b c.p.u. 06 74LS20 -F9 ISO 74LS32 b274LS74 address D7 G -EB CS1 +-AtI bus C. p u IC7a G E9 CK D data lCSb MI bus D2 G -DB D SET OS C D9 0- CK 0 7Ó/ RD c.p.u- D4 B ICS 74LS02 -CB IDRD control A l'O -C9 - bus `1 b,74LS74 ffE3ET 1 IC7b IC7d I19 Decoded W op - codes -J c.p.u. I 274LS74 74LS138 DO -7 '--' data bus CK G SET 0 SET IEI "`"---1Daisy chain FD-+ IC60 j _ G interrupt ED ICBb 1E0 -- D SET IC8a control K KK G -DD CLR CLR (used with INT --. J other three C -CD l 1i274LS109 1, 74LS109 "274 LS74 CK IC4c channels) B -70 D C6b 280-CTC A -6D á IC5 6 unused SET and CLR inputs 50 tied to+5V IC3 RESET O 40 I14d I19 speed to match c.p.u.

instructions has been executed. dumps all the register contents Instruction Correction is automatically into a reserved ram area and made for two -byte op -codes - then enters the monitor counter for Z80 those beginning with CB, DD, program which allows ram to be EI) or FI) - which have two examined and altered as simulator MI cycles. Counting is required. A continue command One function of a suspended during interrupt to the monitor reloads the CTC microprocessor simulator is to servicing so that, for example, and copies the register storage run a preset number of display handling interrupts can ram hack into the registers. A instructions of a program being be allowed to run without normally unused_ instruction, debugged and then stop so that affecting the test. LD L,L (op -code 6D). is register and memory contents Sixteen op -codes are decoded executed to clear. IC, and hence may be examined using a by IC,... If CB, DD, ED or FD remove SET from IC. monitor program. In Z80 is detected on the data bus at Finally, a return instruction is systems, the breakpoint is often the end of an MI cycle, the Q executed. This retrieves the implemented in software by output of IC, is clocked low by address of the next instruction replacing an instruction in the the trailing edge of the RI) from the stack, where it was test program with a Restart pulse. The RFSH refresh pulse, placed when the NMI was instruction (a single -byte Callao which always occurs after an recognized, and the test a fixed address). Ml cycle, clocks IC whose Q program continues from the For this approach, the test output goes high and prevents point where it was interrupted. program needs to be in ram and the second M1 pulse from The RET op -code is counted by working out exactly where to reaching the CTC (counter/ the CTC, but the monitor allows place the Restart code is timer circuit). Output Q is fed for this by adding one to the complicated by the varying back through IC;;, to ensure that number of instructions to be length of Z80 instructions. the next instruction is not also run. Up to 255 instructions may Also, a bug in the test program inhibited should the second byte be run. could prevent the restart code be CB, DD, ED or FD. Instruction counting is from being reached. In this When the CTC down -counter prevented during interrupt design, the test program does reaches zero, it sends a short servicing by IC, whose Q not need to be tampered with, positive pulse on its ZC/TO pin. output is set high when an so that routines in rom may This pulse is inverted to provide interrupt acknowledge cycle is also be single -stepped for the c.p.u. NMI signal. It also' detected (M1 and IORQ both demonstration purposes. (The sets the Q output of IC high low). Output Q of IC, goes low usual wait -state generation which in turn sets the Q output when op -code ED is detected, technique for single -stepping of IC,,, high to inhibit further and if the second byte is 4D, precludes the use of dynamic counting. Using the non- i.e. if the instruction is RETI, rams.) maskable interrupt means that then IC, is toggled, the SET A programmable counter the circuit works whatever bugs signal is removed from IC,h and provides the breakpoint by there may he in the test counting continues from the counting M1 (op -code fetch) program. The CTC channel next op -code. cycles and generating a non- used has its normal interrupts Clearing of the two JK maskable interrupt (NMI) when disabled. bistable elements of IC$ occurs the preset number of The NMI service routine whenever the processor is 62 ELECTRONICS & WIRELESS WORLD MARCH 19135

www.americanradiohistory.com 1 byte 1 byte 2 byte 2 byte op code op-code- op code fetch op -code fetch fetch fetch

M1

IC4aRD

RFSH Stays low DD, CB, if 2nd Ia! IED byte is ÉDorFD or FD CB, DD, ED, or FO ICSaa

ICSb 0 IC9 CK/TRIG

t t c.p.u. may insert memory or i o cycles between op-code fetch cycles, depending on the instructions

Next 2 memory read op -code RETI cycles to fetch-- fetch - op -code fetch return address (1 byte)

RO L

IC4a

(bi RFSH led in this section pulses on if a ED 40 D Strobe probe signal at the B input occurs IC6a This probe has proved during the window at A. invaluable in tracing Polarity of the window and ICBb relationships between read, probe inputs is selected by the ICSaD write and chip -select lines on respective switches. When a microprocessor -based circuit switch is high, its associated IC9 boards. It has two channels. circuit responds to active -high CK/TRIG Section A is the window input inputs and vice versa. and its led lights to indicate that D.J. Ford Next a window has occurred. Probe Welwyn Garden City LD L,L RET 2 memory read op -code mop-code--op-code---cycles to fetch-fetch-- input is fed to section B. The Hertfordshire fetch fetch return address (1 byte 1 1- indicated by the led. The three - RD 4-20mA indicator terminal i.c. provides a 4mA the IC4a Output from industrial process offset which is set using is a the left of it. lc) instruments often constant- potentiometer to RFSH current signal in the range 4- Voltage drop provided by the D 20tnA d.c. This simple device is zener diode ensures that there ICBa Q a monitor for such signals. Its is sufficient voltage to operate accuracy depends largely on the the led and i.c. The second ICSb meter used and with careful potentiometer is for setting to IC9 calibration, an error of ±1'.%, f.s. Rill -scale deflection at 20mA. I L CK/TRIG is possible. M.C. Polgreen RET Presence of a signal is Birmingham counted

reset. Connections from Q to J second byte of the instruction ensure that the devices remain BIT 5, L (op -code CB 6D). cleared until forced to change In the timing diagram, (a) state by a low on the SET shows removal of the second input. op -code byte, (b) resumption of Circuit IC,;,, is cleared by a CB counting after a RETI op -code. The low Q output instruction and (c) resumption inhibits latching of a following of counting after an LD L, L ED byte by IC1, and hence instruction. prevents IC,, from being If no use can be found for the toggled to its clear state by a three remaining CPC channels, SET 5, L instruction followed this device can be replaced by a by LD C,L (op -codes CB ED, chain of any desired number of 4D). Similarly, the high D- LS163 presettable four -bit output of ICr, keeps the K input counters. of ICa high after a CB byte so Peter Ferris that ICN. is not cleared by the London ELECTRONICS & WIRELESS WORLD MARCH 1985 63

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CIRCLE 50 FOR FURTHER DETAILS. 64 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com DIGITAL MULTIMETERS Right to the point

The point is accuracy, under all conditions. Something only a DMM with true RMS AC measurement can achieve. For £165', sorrething only Philips new PM 2518 can offer.

Look at the table and you'll see how important true RMS can be. Look at the PM 2518 and see how much more you get - DC accuracy of 0.1%, plus wide-ranging standard and optional facilities ;including "Backlite" display). u

true RMS 54 5V 5V 5V reading on PM 2518 5J 5V SV 5V ,01 reading on average detecting meter 5t1 5.55V 4.7V 3.2V

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PHILIPS Test & Measurïing Instruments PHILIPS CIRCLE 118 FOR FURTHER DETAILS.

ELECTRONICS & WIRELESS WORLD MARCH 1985 6.1

www.americanradiohistory.com ALARIVIPHONE

meiee,_ Two views to aid construction of Mr Andersen's design. Potential constructors should read the note on page 69. Alarmphone This second part of Per Andersen's article details the circuitry for the emergency autodialler that requires no line connection

When the motor is running, the L1 activated. When H., is low, ICi3a width and output delay values coil in the pump monitor detects is constantly triggered supporting chosen require a steady signal for the magnetic field around it. a low fail signal to the line and at least two seconds before the Comparator IC22 converts this pump monitors. On switch -on output of IC19 goes low. Circuit signal to a square wave that is rec- RESET set RFD high. However, IC18c is coupled as an inverter trig- tified and taken through a couple when the motor stops, Has goes gering the reset input of the bist - of Schmitt trigger inverters to high activating the solenoid and able flip-flop IClad Line RFD now generate the stop signal (STOP). releasing ICi3a The ready -tone is goes low preventing IC13a from This is 'or -ed' to the fail signal picked up and amplified around generating the fail signal and trig- Block diagram shows how providing the term H0«. Under 70dB by ICisab presenting a sig- gering the set input of the dial circuits on the opposite page normal conditions STOP is high, nal of 1.5V r.m.s. at the input of .latch. If the ready tone is not and on page 68 relate. and therefore the solenoid is not the tone decoder, IC19. The band - detected within six seconds, the not-ready timer runs out supply- ing the fail signal to IClad, forcing Reset +24V Stop its output to stay high whatever Pump Power -up happens at the resent input, and monitor ALST deactivation the solenoid. The high output of the dial latch Fail I starts the 1.2Hz generator, IC13e, Fail Not -ready Solenoid Reset I ST Reset which controls the memory out- H off timer driver put buffer and address counter. is Line The buffered signal taken to the monitor RFD b.c.d.-to-d.t.m.f. tone converter 1 consisting of IC4, IC5 and D2 -D31, then to the driver stage and the Comp EDD Dial latch transmitter/loudspeaker. Comparator IC12 compares the outputs of the memory and dis- Read play address counters and upon equality, which means when the

Keyboard Write Alarm encoded number is dialled, the Memory logic generator output goes low triggering the dial +5V +5VS .24V Grid latch to stop the 1.2Hz oscillator. The EOD and RFD signals are +5VS now 'and -ed' for starting the Reset 4444 alarm generator, which will run 11 Address Driver Reset Display Dial logic Power supply minutes determined by IC,,. At DTMF stage RST the end of the period the ALST signal takes the reset input of the sh ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com PUMP MONITOR +5V +5V .24V

R34 2k2 R56 1k

C20a IC20b 8 22 D26 3 Sense 2. coil ,l I 1 2k2 33y 3, 6 R c231,j 35 D _ 32 25 ICJ 3k T2}i C37 R57 e- I I^V 2}2I-+ 1k HOFF L FAIL ALARM GENERATOR ALST CLR OD RFD D 2 .5 Vs CLR a(q - EDO t+SVS IC23 t - +5VS-41- R44 -/ 17- -1\Ati 8n 10n 10M -1 29 100n R45 R46 100k R41 devices R47 1k2 Semiconductor IC20d r-1/V\,- -AJA Tr6 1k , 74LS147 C,, 7407 820k C9_. 3 7489 C,8 LM3900 Il R42 5k1 74LS42 C19 LM567 R 5 48 1k MK5089 C21 74LS20 ST RST OUT s.2 74LS14 C22 LM311 OUT , 74LS30 C25 74L154 IC24 39 R,0 IC24 R3 74LS32 Diodes 1N4148, .--. 1k 5k1 s CV tr CV tr 9 74L121 execpt D, 1 N949 330k R11 74LS00 Tr, BC308 1 DTMF zs 74LS393 Tr2 3 BCY58 11 180k 2 DM8136 Tr, BSX45-10 10n C25+ 330n 10cy C28 74LS08 TR56 BC107 ,3za `26T T220n 2n2 16 1k res T T y

+5V +SV 1 1 1

I C16 _ Display te KEYBOARD C16 DIAL LOGIC LOGIC data D2 to D21

1 2 3 4 5 6 7 8 9 1011 1 12 13 14 1_4 1

17 1 DTMF IC1 13 mi 661 14

0 . 6k8 ICI 6 al 6Ó2 6

3 IC3 IC4 13 tii3 4 riö3 13 1u 7-+5VS 5 0-04 1 1L u 4 0 o 9 3 WE 12

ABC D

1 15 14 13

-4- .5V 95V

IC3 DIAL LATCH 1k fl IC7 COMP 3 Our9 5 471 IC12 au 11 8 RST- CLR 15 RESET flq' 2 T1 86 14 COD 5V C8 13 IC10 16+5V 7 12 RFD RES E T -a. - CLR 0 2 k2 33n IC16 7

15

o 1 t+SV IC14 0 Display Write - address .1. S1 Read

RESET RESET RST

www.americanradiohistory.com ALARMPHONE

not -ready timer low which gener- ates the fail signal which sets the LINE MONITOR machine in the stand-by mode. 6p8 2M C11T The alarm generator produces

R20 270k R26 1M a sound similar to certain police ICt sirens. This was chosen so that R21 C14 R1 10k whoever answers the call, prob- ably not you, is able to distinguish 24}0 C15 R1 MONITOR LATCH I 25 it from all the other telphone sig- 4 18 1M 1p 39k nals. The tone is easily made by V, OUT 5 680k RFD 18c taking the output the R14 10k IC19 R of first sec- C104 AV R17 ki 8 1p 1% C18d IC24 to 6 tion of the control voltage Gnd +5V R27 input of the second section 8n 22 22gc 7 12 r._ 11 C18 -1// thereby modulating it with this 125p 100n 470k . 16 1y 1% lower frequency. To write the telephone num- R28 680k 5V S ber, which can have up to 16 digits, into the memory you sim- IC14 ply St to 29 Z 470k take the write position and key the number at the key-

IC2 board. As a control the number is D24 V RST Vc, read out on the display. On com- OUI 11 FAIL pletion S1 is taken to the read Tr IC13a ALST position. Keyboard data goes NOT -READY RESET CV Gnd TIMER from IC1 (10 -to -4 line converter) HOFF via IC2 (4 -bit latch) to the mem- C19 T 22n CM.. 12p ory, IC3. Each time a key is L14 .i.. depressed, a strobe pulse of around lms is generated from the outputs of IC9. The. negative strobe is used for the write signal to memory and for unblanking of Circuitry requires a solenoid used digits at the display. The supply as well as 5V WAVEFORMS supplies; a battery charger is r positive strobe increments the included in this version. Output from alarm generator memory and display address, counters for each depression of a key. When S1 is taken back to the +2V -- Input to Schmitt trigger, `read' position the memory add- ress counter is reset because of OV IC20a the capacitor C3. The display add- ress counter remains at the num-

Output from op -amp, IC18b ber of digits that previously wa's entered. A read cycle therefore goes on until equality of the two +5V counters. Fms-4. On switching on the machine 4.0V g Outputs from one-shot, IC19 the necessary reset pulses, which

OV have a duration of about 200ms, IC6 IC10. Waveforms at various points 1200 msH are generated from and in circuit are identified in óVReset pulse .Output of IC6 The reason for designing a dis- circuit above and on page 67 play for the machine was the abil- by encircled numbers ity to control the number to be encoded. On a normal telephone you simply hang on and make a re -try if you get the wrong con- nection. In this case, you wouldn't know if the right num- ber was dialled, because the con- nection was made when you were not at home. This is where the display comes in. As it was the most expensive unit in this con- struction, it is designed in a way that makes it easy to leave out if not wanted. Or it could very eas- ily be reduced to eight* digits, if

* Or one digit, for that matter, with sequential readout. Mr Anderson has sug- gested the circuit on page 69 for this low- cost option. The original circuitry for an 8 or 16 digit display is available from the edi- torial office.-dop.ed. 68 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com Signal Explanation

ALT To the line monitor from enable the six -second the alarm generator to timer, whenever a pump notify that all functions malfunction took place. were completed, and to RFD Ready -for -dial goes from generate the FAIL sign. the line monitor to the BLNK From the keyboard logic dial latch to ndicate that to the display to shift the the ready -tone was blanking registers each detected. It also goes to time a key is depressed. the alarm generator, COMP From the keyboard logic where it will be used in to the dial latch to let it conjunction with the know that all digits from EOD signal, to generate the encoded number the alarm signal. were dialed. RST Clears the memory DTMF Tones from the tone address counter upon from the one the machine was Author's original 8 or 16 - dialer to the output power-up or when the developed for. But this will be digit display can be used to stage. function switch is taken fairly simple, as it is only a matter check the stored number; EOD The end -of -dial signal to the read mode. of changing the gain of the input alternatively this sequential a goes from the dial logic RESET Clears the display amplifier and the driver stage. single -digit circuit offers to the alarm generator to address counter upon low-cost option. The only thing to consider is that The inverters are type 7407. provide the alarm signal power -up. the tone decoder needs an input ET the line monitor for the transmitter, when RE Sets of around 1.5 to 2Vr.m.s., and latch HI after power -up, the dial sequence is that the transmitted d.t.m.f. sig- finished. and causes IC13b to FAIL From the line monitor to remain anactive until the nal must not suffer from any kind the pump monitor to FWD signal is received. of distortion. deactivate the solenoid, Clears the display The sense coil is easily made, when all functions are blanking registers during as it monitors 50Hz. In my case completed, or when the power -up. the coil from a scrapped relay was ready -tone did not occur STOP Message from the pump used with good results, but within six seconds from monitor to the solenoid almost anything will do. Some of driver to let i; activate the point where the the functions in the circuit could receiver was lifted off the the solenoid and Whilst many telephone be made in a simpler way, but hook. generate the HOFF exchanges in Europe will HOFF From the pump monitor signal. they were designed partly to keep handle dtmf dialling, only a to the line monitor to the expenses down, and partly minority of UK public because the components were exchanges (unlike private this is enough for local telephone the time it takes to make the dial available. branch exchanges) can at numbers. It was designed with 16 and deliver the alarm tone. The d.t.m.f. circuitry is sup- present. British Telecom digits to make it fit to the memory Proper switching from mains to plied from a separate regulator to expect that over two million capacity of the machine, and to battery will in such a case be secure optimum performance subscribers will be able to to secure storing of the and correct functioning of the dial use dtmf dialling by the end allow viewing of the number required of 1986 as a result of dialled at any time. memory contents. logic. As there are no adjust- continued expansion of The four data lines to the dis- It might be necessary to adjust ments in the machine, it should System X. As with modem play are buffered in ICI, and then the machine to different types of work immediately after careful designs, such equipment taken to the display data bus. telephones, as these could have assembling. must have BATB approval to Position of the digits are deter- diverging input/output levels be legal. mined by the 4 -to -16 line

decoder, which is controlled by MEMORY WRITE CYCLE MEMORY READ CYCLE the display address lines. The address is incremented by one Keyboard data J L Write enable, WE J each time a key is depressed, and 'tPLH this will enable the digits in turn Keyboard strobe Pump STOP from left to right. To keep unused 2 sec t-- digits blanked, the two 8 -bit shift PLH r Write enable, WE Ready for dial, RFD i registers, IC42, IC43, are coupled t lsec tPLH as blanking latches controlling - PIN Clock mem. ad. cntr Read data clock,IC46 BI on the displays. _J . the -terminal -0-2 sec The latches are reset during Clock displ. cntr Transfer data for dial power -up to provide a blank dis- ___n_51.41_51_41_ play before entering any digit. tPoi As the instrument is battery Blanking off, BLNK Increment address cntr. powered the supply circuit is sim- PHL ple. Only a couple of voltage Output IC12, COMP Propagation delay time regulators with the necessary tpLH & ttHL: in appropriate gates capacitors at the outputs are End -of -dial, E00 used. Of course a regular mains PLH -1yZmin- supply could be used to support Start alarm generator @MEL

the power in the stand-by mode, tPHL'" which will reduce the capacity of Stop alarm generator L_ the battery essentially. In this case the battery is only needed for Return to standby, FAIL less than two minutes, which is ELECTRONICS & WIRELESS WORLD MARCH 1985 69

www.americanradiohistory.com ri COMPACT DIGITAL AUDIO Principles of optical by J.R. Watkinson storage

Fig. 1. Objective lens of a C D pickup has a numerical This second article in our new series details aperture (n.a.) of 4.5, so the outermost rays will be the physics of the readout process inclined at about 27° to the normal, though refraction at the air/disc interface changes A fundamental goal of the com- indicator clusters for this to 17°. Light focused to a the domestic environment of the same spot on the information layer pact disc is that it should not reading. reasons. enters the disc through a require any special working envi- The first article (January issue) An alternative material is circle only O.7mm dia. giving ronment or handling skill. The introduced the idea through the polymethylmethacrylate good resistance to surface bandwidth required by digital thickness of the disc. This appro- (p.m.m.a.), one of the first opti- contamination. audio is such that high density ach causes the readout beam to cal plastics, known by the trade storage is mandatory if reason- enter and leave the disc through names of Perspex and Plexiglas, able playing time is to be the largest possible area of the and which is used extensively in obtained, and this implies short surface, see Fig. 1, which shows illuminated signs and aircraft Fig. 2. Step height is wavelengths. The advantage of dimensions involved. Despite the canopies. Makrolon is preferred designed to produce a phase optical playback is that the rea- minute spot size - around by some manufacturers because reversal in reflected light dout beam can be focused onto 1.2µm dia.- light enters it is less hygroscopic than compared to light which has the medium from a distance, through a p.m.m.a. reflected from the mirror 0.7mm dia. circle. surface so that destructive whereas magnetic recording Thus surface debris has to be In the readout process the interference reduces reflected requires intimate contact and three orders of magnitude larger depth of the steps is designed to power. Spot size here is implies a wear mechanism, a than the readout spot before the be l wavelength of the light used, symbolic only, the spot being need for periodic cleaning, and beam is obscured. The size of the Fig. 2, so that light reflected from a diffraction pattern. susceptibility to contamination in entry circle is a function of the the mirror surface travels X/2 fur- refractive index of the disc mate- ther than light reflected from the rial, the numerical aperture of the step surface, and so results in optical system and the thickness destructive interference. The of the disc. principle is optimized for one Because of readout through the wavelength, and so light source Objective fens thickness of the disc, surface must be monochromatic. ' scratches on the readout side are The wavelength in the medium tolerated very well. In extreme is determined by the refractive 27 = Siri 0.45 cases of damage, the scratch can index; the specified light source often be successfully removed has a wavelength in air of 780nm Air BB! with metal polish. Conversely, and the refractive index of 1.55 Disc the label side of CD is much more causes this to become 500nm Sin 27° -ii 17° Si - 1.55 vulnerable, as the lacquer coating within the disc. The step height is 12mm is only 30µm thick. For this rea- about one quarter of this figure at son, writing on the label side is 0.11 to 0.14m. As the incident 11 Information layer not recommended; pressure light cannot return the way it from a ballpoint pen could cause came because of interference, it mechanical damage to the infor- will exit at any angle that permits mation layer, and solvents from constructive interference as a dif- marker pens have been known to fraction pattern along a discra- penetrate the lacquer and corrupt dius. the disc. A common party piece is Dimensions of the track struc- to show off the error correction ture are closely comparable with system by writing on the readout those of the Philips Laservision side with a felt tip pen. This is disc, on whose optical technology relayively harmless as the disc the compact disc is based. Both base material is impervious to are diffraction -limited, i.e. the most solvents. dimensions involved are as small The base material of CD is a as permitted by the wave nature polycarbonate plastics material of light. produced by Bayer under the It is not possible to focus light trade name of Makrolon. With to a point even with a lens free excellent mechanical and optical from aberrations. When this is stability over a wide temperature attempted, the result is an Airy range, lends itself to precision disc whose size is a function of the moulding and metallization. It is wavelength and the numerical commonly used for automotive aperture of the objective. 70 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com is cut, the Fig. 3. Two levels of When the master exposure sensitivity of the effective spot size is about resist determine the size and 0.41.1m, determined by balancing edge slope of the steps on the the power of the cutting laser disc surface. A large against the sensitivity of the res- exposure results in large step ist. The resist has two sensitivity with gentle slope (a) while levels, a level where etching will less exposure results in just begin, and a level where smaller bump with steeper etching will go through to the and sloped sides (b). glass blank, Fig. 3. Increasing the exposure produces pits with gradually sloping edges, which release from the mould easily but are optically inferior to steeper edges. A compromise is reached by control of the exposure'. To achieve the very small effective spot size needed for cutting, the resist sensitivity is in Fig. 4. Amplitude response the area of the half -power level of of laser pickup. Maximum the Airy disc intensity function, operating frequency is about and a krypton laser with the short half of cut-off frequency Fe wavelength of 350nm is used. Theory This requires an aparture of about 0.7. It is the thickness of the res- Measurement with ist that determines the height of less than perfect focus the bumps on the finished disc, which should bel the wavelength of the player laser in the disc material. f Optimum size for the playback Maximum Equivalent Fc spot is rather larger than that of operating the cutting spot: for destructive frequency interference to cause complete cancellation in the reflected beam the energy reflected from the top be within the Marechal criterion2. the bit rate; these are different of a step should equal the anti - Clearly the n.a. and wavelength due to the channel code used and phase energy reflected from the must also be closely specified. is discussed later. mirror surface. This simplistic The cutter spot size deter- Fig. 5 shows the structure of a condition is never obtained in mines the reader spot size, which maximum frequency recording practice, and typically the pres- in turn controls the shortest and the relationship of the spot ence of a long bump reduces ref- wavelength of modulation along intensity function. lected power to about 25% of that the track that can be read. The The next article deals with the obtained from the mirror surface. optical cut-off frequency, where mechanisms necessary for track A larger spot in the player also the output falls to zero, is 2V X following and focus. eases the task of track following, (n.a.)/a., where V is the linear permits the use of a low-cost vis- track velocity. The minimum lin References and a velocity CD is ible wavelength laser ear of 1.2m/s so 1. Laser beam recording of video master smaller aperture, which in turn the cut-off frequency becomes discs. B.A.J. Jacobs Applied Optics July improves the depth of focus. 1978. 2. Principles of Optics. The specified wavelength of fc = 2 X 0.45 X 1.4/780 X 10-9 Born and Wolf (Per- 780nm and n.a. of 0.45 produce = 1.6MHz gamon). an Airy function where the half power level is at a diameter of The frequency response of the about 1µm. The first dark ring pickup falls linearly to the cut-off will be at a diameter of about frequency and Fig.4 that actual 1.9µm. measurements are only a little Intensity Allowable crosstalk between worse. It is necessary to limit the function tracks then determines the track maximum operating frequency to Half power pitch. The first ring outside the about half the cut-off frequency level central disc carries some 7% of otherwise immunity to noise and First dark ring Fig. 5 Structure of a the total power, and limits cros- crosstalk is impaired. Maximum at 1.86pm radius maximum -frequency stalk performance. Track spacing frequency is 720kHz, which rep- recording, related to the is chosen such that with a slightly resents an absolute minimum intensity function of an defocused beam, and a slight wavelength of 1.6661.1m, or a step objective of 0.45 (n.a.) with tracking error, crosstalk due to length of 0.833µm when the min- 780µm light. Spacing puts tracks in dark rings, the central spot seeing adjacent imum speed of 1.2m/s is use for a 1.666pm adjacent minimum reducing crosstalk. As the tracks is no worse than the limit. 75 minute disc. spot has an intensity Since objective aberrations will Standard one -hour discs have a function, it is meaningless to increase spot size and crosstalk, minimum step length of 0.972µm specify spot diameter without the CD specification requires that at a track velocity off 1.4m/s. The some reference, such as an the objective performance shall maximum frequency, 720kHz, intensity level. ELECTRONICS & WIRELESS WORLD MARCH 1985 71

www.americanradiohistory.com FEEDBACK

language of 'the calculus' of the editorial of current in a wire the Quad 405 specific design. If CAUSALITY fluxions' to describe such time connected to an e.m.f., the he doesn't like the 405, he is at The idea of causality as time delay interactions. In the limit interaction is too fast for human liberty to say so, but he should delayed control is essential to as the interaction time tends to reaction or contemplation. The not say that "it is quite logical reasoning (February zero we may use exact initial transient interaction incapable of using the current Editorial). Reasoning is a derivates and formulate our could be time expanded and dumping technique" without process of the mind so it is true laws using differential equations analysed in detail as it settles some experimental that causality, as "a necessary which then remain valid only for down to an assymptote which substantiation. Our model connexion", exists in the mind. pseudo instantaneous or corresponds to the classical circuit does this, and we are Conversely if the reasoning asymptotic steady state circuit laws. convinced that the design does corresponds to events in reality interactions. P.J. Ratcliffe incorporate a feedforward then causality can be said to Conversely however, some Stevenage novelty. There is a clearly exist there just as much. This is people may be misled into Herts discernible distortion null in the the working hypothesis for saying that since the time 405 (albeit not perfect) as the scientific theorizing, and interval tends to zero it is bridge components are varied, causality provides the essence negligible. Then the "constant and the unmodified amplifier is inherent in mechanistic conjunction" means that the CURRENT fairly close to optimum. We are 'explanation', conferring a change of flux and induced sceptical that a circuit of sense of 'understanding' in e.m.f. are so essentially DUMPING comparable performance and appreciation of this knowledge. simultaneous as to be Mr McLoughlin's replies to the simplicity (with the dumpers The problem of whether impossible to unravel. This is an letters regarding his article on biased off) can be produced reality is logical is itself beyond ingenious erroneousness. current dumping (Letters, 1984 without the feedforward reason: logic deals with The incorrectness of this February pp. 46, 49, 50) need technique. Mr McLoughlin relations between things that argument can be simply a response, since we feel some states that the 405 operates by already have the attribute of explained using a special case of our statements have been relying on the modification of 'existence'. When we come to as an example so that the truth misinterpreted. the feedback at h.f. provided by ask how does anything at all seems obvious. Consider the We think that the "incautious the inductor L. He argues that exist we have progressed 'thought experiment of comparisons with other "It is left to the usual negative beyond the confined circular increasing the size of the coil so arrangements", which "had to feedback from E (his Fig. 12) to structure of logic into the realm its separation from the magnet be withdrawn on grounds of reduce" the dumper distortion. of metaphysical speculation. at its centre is enormous (such instability" are important, for We would claim that there is no To demonstrate that causality as the radial distance to the the success of an electronic usual feedback from E, and that does exist in reality external to nearest star, about 4 light technique such as current the feedback from before L is any mental framework consider years). As an initial condition dumping often depends on the meant precisely to correct the an idea that occurred to me of we may suppose the magnetic practicalities of typical circuits. signal after L. This is error using Lenz's law of induction field has existed throughout all Should one think of current cancellation and is not for a system of magnetic space for all time upto the (god- dumping as dominated by associated with normal braking to support an elevator like) 'present'. When the coil feedback or by feedforward feedback, although it is used against free fall. moves relative to the magnet it error correction? We think most with feedback. The 405 may As the coil falls around the cuts lines of flux instaneously in of us would agree that without not embody the technique magnet (or vice versa) the its environment and an e.m.f. is feedback the majority of perfectly, as many of the details motion through the lines of flux induced. However the amplifiers would be impractical. show, but the primary claim induces a current which in turn information that the coil has However, current dumping that it uses an error cancelling produces a field tending to moved and produced an e.m.f. establishes a new concept in technique is in no way oppose the motion. and opposing magnetic field amplifier design that is clearly compromised. One could insist The important aspect of the propagating out at the speed of different from normal feedback, on sticking to a feedback -only interaction in this abstract light will take a definitely and is clearly traceable to explanation, but once one sees 'control system' is that the significant time (compared to a Black's original feedforward how the concept is clearly response tends to oppose the human lifetime) to read the concepts. We have never stated traceable to feedforward error stimulus. It can never cancel it magnet and reciprocally for this that "feedforward alone is the correction, then it seems to us exactly simply because of the to react and oppose the relative only correct explanation of only logical that subsequent chain of causality. (There is motion. (With such action at a current dumping". On the descriptions are based on the similar behaviour in a virtual distance explicitly formulated it contrary, we have always two intertwined techniques. earth feedback amplifier, virtual also becomes obvious that at insisted that current dumping J. Vanderkooy being the 'operative word'.) So each instant (God's point of is a blend of both error S.P. Lipshitz causality demonstrably exists in view) forces cannot possibly be feedforward and feedback (see University of Waterloo reality. 'equal and opposite' and so we our second paragraph), and we Ontario In formulating his mechanics, need a system of mechanics feel it is most improper to Canada Newton found the need to even more fundamental than represent our views in such a invent the mathematical Newton's) . biased manner. When we can vary the It is very clear from our AES degree of Humes "constant article that the inductor conjunction" then even the characteristics refer to those MORSEMAKER most stubborn of anti scientific inductors which we constructed After completing a Morsemaker psychodelic mind -destroyers for our model circuit. Thus (June, 1985), it was found that ought to agree (out of common "this damaging criticism of the some of the 4013 devices did courtesy) that "there must truly Quad 405" is wholly inaccurate. not change state in a reliable be some causal connection in There is nothing wrong with the manner, and the following reality, that is, external to any inductor in the Quad 405. Mr modifications were required mind: though as to the McLoughlin's theoretical before the unit would function mechanism, that needs further analyses of current dumping properly. elucidation." have descended to unjustified, An additional lOn capacitor For the example suggested in unsubstantiated criticisms of was connected in parallel with 72 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com i.c. 4013/1 via a wire link. Pin information processing and 4013/2 8 of i.c. 4013/1(b) was then manipulation, communications, connected to pin 4 of the 'one- machine intelligence, man - shot'. The extra i.c. and machine interface, data base associated components were networks, citizen's privacy, mounted on a small p.c.b., word recognition and machine located near the main board speech, software, from which is obtained the microelectronics, advanced necessary power supply. The information processing, expert delay -control spindle was systems - one could go on and brought to the outside of the on. instrument case, for Can it then be right that we 0V convenience. as a nation spend more money R.J. Canaway and skilled resource on teaching Maidenhead French and German in schools 500k Berks. than we do on IT? How much is `Character end that effort going to contribute to switch wiper our GDP in five years time? 10p .. How can we justify departments 4001 IT EDUCATION of Business Studies in schools In November, 1983, the but no departments of IT? Has commission of the European anyone considered whether we Pin 7 ED, Community issued the following should be giving over half of the ( 0V facts as part of its official school curriculum to IT journal no. C321, volume 26. education? Do we really believe that already existing between lOn capacitors already "Some 6% of the Community's that our present curriculum is pin 3 and earth of i.c. 4013/ incorporated across the supply gross domestic product (GDP) enabling our children to deal 2(a), directly to pins 3 and 7 on lines with several 471x 10V is produced by Information rationally with the world as it is the underside of the printed - electrolytic capacitors to Technology (IT) industries. A and as it will be? Do we really circuit board. Without this provide additional smoothing further 29% of GDP is produced believe that a child's job capacitor, "nonsense" and de -coupling at various by industries which apply IT in prospects could be anything but characters consisting of dots places on the p.c.b., a major way. Another 20% of improved by a far higher only, appeared. particularly as the device is GDP is derived from other understanding of the A lOn capacitor was powered by a battery, which industrial sectors with a high technologies of the future? connected between pins 11 and could develop internal information content". In other Let us acknowledge that we, 7 of i.c. 4013/3(b) on the resistance in the course of time, words, over half of the GDP of in Europe, are engaged in a underside of the p.c.b. Without adding to that exhibited by the Europe is derived from, or is battle with the Americans and this capacitor, a few dots were diode. heavily dependent on, IT. By the Japanese for mastery of the generated, followed by a Finally, a useful addition to 1990, IT will be the world's high addded-value industries of continous tone. Both capacitors the Morsemaker is an largest manufacturing sector. the future. Some we have lost are of the miniature, low - adjustable delay between The new information irrecoverably e.g. mainframe voltage ceramic type. characters which enables the technologies will be the key to computers. But, on the whole, With the two capacitors in character generation speed to industrial advance in our much of the rest is up for place, figures were generated be increased so that rhythm is lifetime and national (i.e. UK) grabs. And if this is true of correctly, but letters involving apparent, yet allows a slow participation in these advances Europe, how much more is it of more than one changeover, e.g. reader respite between demands national development the UK, with its tremendous CXPQY etc., were not characters. of the skills required to provide dependency on exports? produced, and also the This was achieved by the labour and intellectual It is conceivable that some "blocked" dit-dit-dah-dah interposing a 'one-shot' infrastructure to such advances. may regard the repositioning of frequently occurred. This was between the wiper of the Trite it may be, but no less IT in the curriculum as a cured by removing the lOn "character -end" switch and the true, that we are undergoing a deliberalising move; that the capacitor from pin 3 of the dot - SET pin 8 (previously isolated as revolution in industrial school may become less arts dash latch 4013/1(a). described below), of control - methodology. Moreover, in oriented. The latter is inevitable Randomising was also improved latch i.c. 4013/1(b). The pulse parallel, the very fabric of our but the former need not be so, on this particular model by from the switch activates the lives is being irreversibly with sensitivity and care. One shorting -out the diode 'one-shot', causing the output influenced by IT; our shopping, would not recommend the connected to pins 3,4,5, of i.c. to go high, this in turn holds recreation, home life and abolition of arts subjects, but 4025/5(b) which considerably the control-latch in the education are all affected - rather their de-emphasising. reduced the number of "character -end" mode for the and will increasingly become From my view in one of our consecutive 'repeats' in a string duration of the 'one-shot' pulse. more so. These facts and advanced technology of characters. The 'one-shot' was formed by conclusions are not in dispute. companies, some of the future Switching disturbances on the connecting two elements of a It is how we as a nation are can be seen - many others in positive supply line had been 4001 quad 2 input Norgate as addressing this present and the IT industries see likewise. previously observed on an shown in the sketch, the future that prompts me to write Surely it is time for a dialogue oscilloscope, and found to be remaining i.c. inputs being today. to start between the due to the effect of the series connected to pin 7 (OV). Small For I believe that our primary educationalists and the IT resistance of the safety diode on portions of the printed-circuit and secondary school education industrialists? Our children's the supply voltage regulation. track on either side of pin 8 of system is not reflecting the part in the future could be at Whilst there was no apparent i.c. 4013/1 were carefully importance of IT. IT is not stake. effect on the performance of removed (leaving pin 8 about a computer in every Ian Bilsland this unit, it was considered isolated), pin 7 of i.c. 4013/2 school. IT is about many Graphic Information Systems desirable to augment the 21.i and being re -connected to pin 7 of things, but, primarily: Limited ELECTRONICS & WIRELESS WORLD MARCH 1985 or 73

www.americanradiohistory.com CABLE T.V. HEAD END AND REPEATER AMPLIFIERS

SINGLE CHANNEL AUTOMATIC GAIN CONTROL AMPLIFIERS TAG4863 Gain 48dB, maximum output 63dBmV. Regulator + or - 8dB. Power requirement 14V 210mA. TAG4063 Gain 40dB, maximum output 64dBmV. Regulator + or - 16dB. Power requirement 14V 210mA.

SINGLE CHANNEL AMPLIFIERS TSS4663 Gain 28-46dB adjustable. Maximum output 63dBmV. Power requirement 14V 170mA. TSS3062 Gain 12-30dB adjustable. Maximum output 62dBmV. Power requirement 14V 26mA.

DRIVER AMPLIFIERS TS1030FM FM driver amplifier. 10dB Gain. Maximum output 30dBmV. Power require- ment 14V 10mA. TS1030B3 Band Ill driver amplier. 10d8 gain. Maximum output 30dBmV. Power requirement 14V 10mA. TS1030UHF UHF driver amplifier. 10d8 gain. Maximum output 30dBmV. Power require- ment 14V 10mA. TS1040S Single channel UHF driver amplifier. 10dB gain. Maximum output 40dBmV. Power requirement 14V 10mA. (Quote channel required).

DISTRIBUTIONAMPLIFIERS

7E2042 Domestic distribution amplifier. 1 input, 1 output. Gain 20dB. Maximum output 42dBmV.

TE1638 Domestic distribution amplifier. 1 input, 2 outputs. Gain 16dB. Maximum output: 2 at 38dBmV. TS2046 40-860MHz. Gain 20dB UHF. 18dB VHF. Maximum output 46dBmV. TS2846 40-860MHz. Gain 28d8 UHF, 22dB VHF. Maximum output 46dBmV. TS2845 Separate UHF/UHF inputs. Gain 28dB UHF, 22dB VHF. Maximum output 46dBmV. TS2054 40-860MHz. Gain 20dB UHF, 18dB VHF. Maximum output 54dBmV. TS2060 40-860MHz. Gain 20dB UHF, 18dB VHF. Maximum output 60dBmV. CHANNEL CONVERTERS TS5565 Gain 55dB UHF, 55d8 VHF, 42dB FM. Maximum output 65dBmV. TCUU UHF-UHF Single channel converter. Gain adjustable +2c113 -16dß. Maxi- mum output +26d8mV. Crystal controlled oscillator. Power requirement REPEATER AMPLIFIERS 14V 25mA. (Quote Channels required). TSC3660 Repeater. Gain 16-36dB UHF, 10-30dB VHF. Maximum output 60d8mV. TCUV As TCUU except UHF to VHF converter. (Quote Channels required). TSC3665 Repeater. Gain 16-36dB UHF, 10-30dB VHF. Maximum output 65dBmV. TCVU TCUU As except VHF to UHF converter. (Quote Channels required). TSC3060 Repeater. Gain 10-30d8 VHF. Maximum output 60dBmV. QUALITY AT LOW COST TAYLOR BROS (OLDHAM) LTD LEE STREET, OLDHAM - TEL. 061-652 3221 - TELEX 669911

CIRCLE 120 FOR FURTHER DETAILS.

HOME CONTROL BT STYLE PHONE CENTRE CONNECTORS

This kit enables you to control up to 16 different appliances by means of coded Line Jack Units - CIRCUIT ANALYSIS pulses in the mains wiring which maybe Master Unit (first decoded by special receivers anywhere in line unit) has bell on CBM/PET or COMMODORE the house. The transmitter may be con- capacitor and 64 trolled manually or by the computer inter- surge arrester. face your favourite An all machine code program for the rapid analysis of linear enabling micro to Flush or surface mounting. Screw con make your coffee in the morning, switch nectors. electronic circuits. lights anywhere in the house, or your Master (flush) 1101 E3.00 This package electric blanket in your bedroom. Just 1960 evaluates voltage gain, current gain, input Master (surface) 1121 £3.00 think of the possibilities and no wiring! 1960 impedance and output impedance in - Master (mini surface) 1960 1131 £3.50 magnitude phase angle This kit comprises a transmitter with pre - Secondary (flush) 1960 1 141 E2.65 form. drilled box and two receivers. Secondary XK112 £42 00 (surface) 1960 1161 £2.65 Additional Receivers Secondary (mini surf) 1960 1171 £3.00 Program features: XK111 £10.00 Dual outlet adaptor 1960 1 181 £4.20 Capacity 30 nodes, 100 passive components, 20 active sources. 4 -way line cord - with plug to spade ter minals 1960 1201 £2.00 Uses 32k RAM 4 -way line cord (960 130) £0.20 per m Handles transistors, F.E.T., Op-amp., transformer and transmission line. Cct model may be simple or complex. MICROPROCESSOR Simple, rapid, component value or parameter changes. TIMER KIT Hardcopy of all results, including graphs. ELECTRONIC LOCK KIT Graph axes may be LIN/LOG/db as appropriate with automatic Designed to con- scaling. With hundreds of uses indoors, garages, trol 4 outputs Maximum or minimum value of all circuit functions. car anti -theft devices, electronic equip- independently ment, etc. Only the correct easily switching on and Unity gain bandwidth and slope of voltage gain characteristic at changed four -digit code will open it! Re- off at preset times this frequency. quires a 5-15V DC supply. Output over a 7 -day 750mA. Fits into standard electrical wall cycle. LED dis- Bandwidth at 'x'db down on the response at any freq. box. play of time and day, easily programmed Hardcopy of component list and performance via 20 -way keyboard. Ideal summary. Complete kit (except front panel) for central Filing XK101 E11.50 heating control (including different of circuit details and last used parameter values for the switching Electric Lock Mechanism for use with times for weekends). Battery rapid loading of the circuit. existing door locks and the above kit. back -up circuit. Includes box. Comprehensive (Requires relay.) 12V AC/DC coil. 18 time settings. instructions with many examples. 1701 1501 £14.95 State model and disc drive number. Cassette to order. CT6000K £39.00 TOP QUALITY ... TOP SERVICE Xk114. Relay Kit for CT6000 Written by a design engineer for other engineers. BOTTOM PRICES! includes PCB, connectors and Many satisfied users. In use for two years. Fp FREE CAE ALOGUE ERAP 9 6 SAF one relay. Will accept up to 4 ange ati ai we.p 5 Europe. r666 elaawng GAFnS N,, 5,,,, Mon Gook 6r , Shag ones ºom swn +0.m mm 701 115 Additional Relays f165 s,eu veeEseaauoE var =nr S.J. BRANSON ELECTRONICS 111 Park Road 1 1- 13 Boston Road Peterborough PE 1 2TR London W7 3SJ Tel: (0733) 67604 ORDERS ENQUIRIES im 01-567 8910 01 579 9794 01-5792842 TECHNICAL AFTER 3pm CIRCLE 76 FOR FURTHER DETAILS. CIRCLE 24 FOR FURTHER DETAILS. 4 ELECTRONICS & WIRELESS WORLD MARCH 1985

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 5052 output; TTL output; external sweep mode. NEW TG502 SWEEP/FUNCTION GENERATOR Main generator features as TG501 plus iriierrial 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 thcndcrTelephone: (0480) 64646 Telex: 32250. ELECTRONICS LIMITED CIRCLE 6 FOR FURTHER DETAILS. Happy Memories E.M.S. POWER SYSTEMS Part type 1 off 25-99 100 up

4116 200ns 1 25 1.15 1.10 4164 150ns Not Texas 3.35 3.10 2.90 Aor 2114 200ns Low Power 1 75 1.60 1.55 2016 150ns 3 65 3.35 3.10 6116 200ns Low power 7.75 Call Call 6264 15Ons Low power 19.95 Call Call 2716 450ns 5 volt 3.85 3.45 3.30 2732 450ns Intel type 4 75 4.25 4.10 2732A 350ns 5.25 4.69 4.50 2532 450ns Texas type 3.85 3.45 3.30 2764 300ns Suit BBC 5 95 5.50 5.25 27128 300ns Suit BBC 14.20 13.65 12.60 Solve all your Power Problems by contacting E.M.S. Low profile IC sockets: Pins 8 14 16 18 20 24 28 40 Pence 12 13 14 16 18 24 27 38 E.M.S. specialise in systems to eliminate your Available now - The ROAM BOARD for the BBC Micro. Reads power problems. Roms via a Low Insertion Force Socket and saves their contents as files, then reloads a file into its sideways Ram as Products range from 35VA switched square wave required. Full details on request. Power Packs to 1KVA fully uninterruptible sine. wave systems. 74LS series TTL, large stocks at low prices with DIY discounts starting at a mix of just 25 pieces. Write or phone for list E.M.S. also manufacture chargers which range up to 60 amps. Please add 50p post & packing to orders under £15 and VAT to total. Access welcome, 24hr 'phone service on (054 422) 618 Non -Military Government & Educational orders welcome., £15 minimum. For further details please contact: E.M.S. Manufacturing Limited HAPPY MEMORIES (WW) Chairborough Road Gladestry, Kington High Wycombe Herefordshire HR5 3NY Bucks Tel: (054 422) 618 or 628 Tel: (0494) 448484

CIRCLE 59 FOR FURTHER DETAILS. CIRCLE 48 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com From SAure, u microphone

L L

Presenting a remarkable concern is pre- privacy buttons, In short, the AMS breakthrough from Shure setting the individual AMS 28 free discussion or single represents a major - microphones, mixer volume levels. speaking facilities - and advance in sound and logic technology all Its mixers (4- and many other important technology. For further combined in one totally 8 -channel available) capabilities. information or a integrated system of quite can easily be linked to The AMS offers a demonstration, simply astounding aural quality. control over 200 choice of four effective contact Shure at the Each microphone has separate microphones. types of microphone for address below. complete independence Which makes the all purposes: the within the system, AMS absolutely unintimidating Low - eliminating all ideal for Prof ile AMS22; the AMS28 unwanted conferences and Lavalier for wearing round sounds symposiums (though the neck; the adaptable it performs equally AMS26 Probe for table, AMS 24 impressively in floor stand or gooseneck churches, courtrooms, 1 mounting; and the AMS24 outside AMS 22 a specially tailored teleconferencing and Condenser 120 acceptance broadcasting). s;:t specifically window. And And advanced logic designed continuously analysing its terminals provide for the own local acoustic unprecedented gooseneck environment. allowing flexibility for unit. each channel to adapt including AMS by itself autonomously as audio conditions change. In fact, the AMS (Automatic Microphone System) is so simple to use that an operator's only HURE AMS 26 HW International 3-5 Eden Grove London N7 8EQ Tel 01-607 2717

CIRCLE 126 FOR FURTHER DETAILS.

OSCILLOSCOPES NEW EQUIPMENT GOULD OS4000 DIGITAL STORAGE. Dual HAMEG OSCILLOSCOPE 605. Dual Trace 60MHZ Trace £650 Delay Sweep. Component Tester £515 GOULD 053300B. Dual Trace 50MHZ Delay HAMEG OSCILLOSCOPE 203.5. Dual Trace 20MHZ Sowter Sweep£400 ComponentTester £201 TELEUIPMENT D83 Dual Trace 50MHZ Delay Sweep £400 BLACK STAR FREQUENCY COUNTERS. P&P £4 PHILIPS PM3370 Dual Trace 150MHZ Delay Meteor 100 -100 MHZ £95 Sweep £375 Meteor600-600MHZ £121 COSSOR CDU150 Dual Trace 35MHZ Delay Meteor 1000 - 1GHZ £105 Transformers Sweep £200 BLACK STAR JUPITOR 500 FUNCTION With 40 years experience in the design and manufacture of several hundred S.E. LABS SM111 Dual Trace 18M HZ AC or external GENERATOR Sine/Square/Triangle 0.1HZ - thousand transformers we can supply DCoperation £175 500KHZ. P&P £4 £110 Ex-MINSTRYCT436 Dual Beam6MHZ £75 AUDIO FREQUENCY HUNG CHANG DMM 6010. 3} digit. Hand held 28 ranges including 10 Amp AC/DC. Complete with TRANSFORMERS OF EVERY TYPE SIGNAL GENERATORS batteries & leads. P&P £4 £33.50 HEWLETT PACKARD 620A 7-11GHZ £950 MULITMETER type U4324. 33 ranges. Complete YOU NAME IT! WE MAKE IT! HEWLETT PACKARD618B3.8-7.6GHZ... £950 with batteries and leads. P&P £4 £16 MARCONI TF1060/2450 - 1250M HZ £150 OUR RANGE INCLUDES MARCONI TF2008 AM/FM 10KHZ - OSCILLOSCOPES PROBES. Switched X1; X10. P&P Microphone transformers (all types), Microphone Splitter/Combiner transfor- 510MHZ £1,200 £2 £11 mers. Input and Output transformers, Direct Injection transformers for Guitars, MARCONI TF1 O66B/1. AM/FM 10-470MHZ. £900 MARCONI TF995A/2. Multi -Secondary AM/FM 1.5 . output transformers, Bridging transformers, Line transformers, TANDON Line transformers to G.P.O. Isolating Test Specification, Tapped impedance MARCONITF1144H/410KHZ 2MHZIDMHZ 5'/," FLOPPY matching transformers, Gramophone Pickup transformers, Audio Mixing Desk DISC DRIVES'/, HEIGHT transformers (all types), Miniature transformers, Microminiature transformers for Single Sided Double Density £75 PCB mounting, Experimental transformers, Ultra low frequency transformers, MULTIMETERS DoubleSided Double Density £100 Ultra linear and other transformers for Transistor and Valve Amplifiers up to 500 PHILIPS OMM 2517.4 digit. Auto ranging etc . £95 Brand New. Complete with information p&p £5. watts, Inductive Loop Transformers, Smoothing Chokes, Filter, Inductors, Ampli- Complete with Batteries, Leads (Un -used) P&P .£S fier to 100 volt line transformers (from a few watts up to 1,000 watts), 100 volt line AVO 8 Mk5. Complete with Batteries, leads & transformers to speakers, Speaker matching transformers (all powers), Column carrying case. P&P £7. £90 STEPPER MOTORS Loudspeaker transformers up to 300 watts or more. AVO TEST SET No1. (Very similarto AVO 8X) ..£80 Type 1. 200 Complete with Batteries, leads & carrying case. Stepsoz4 Phase (5 wire) 12/24V 25 We can design for RECORDING QUALITY, STUDIO QUALITY, HI-FI QUALITY OR P&P £7 inch. 1. 20ìa £15 P.A. QUALITY. PRICES OUR ARE HIGHLY COMPETITIVE AND WE SUPPLY LARGE AVO MULTIMINOR. Complete with Batteries, leads Type 2.6/12 Steps 3 Phase 12/24V. 1'/." dia. £2 ea 5 OR SMALL QUANTITIES AND EVEN SINGLE TRANSFORMERS. Many standard & carrying case. P&P £3 £22.50 for£7.50 are in stock and normal dispatch are short and sensible. Type 3. 24 Steps 4 wire 5V 3.3A 0-250rpm 0- OUR CLIENTS COVER A LARGE NUMBERg OF BROADCASTING Oe AUTHORITIES, MARCONI TF2600 VALVE VOLTMETER 12 ran es 200PP52'/,"dia £10ea MIXING DESK MANUFACTURERS, RECORDING STUDIOS, HI-FI ENTHUSIASTS, 1mV-300VFSD Type 4. 200 Steps 120V (3 wire) 25oz inch. 2'/,' BAND AND PUBLIC GROUPS, ADDRESS FIRMS. Export is a speciality and we KINGSHILL dia £4 have overseas clients in the STABILISED PSU Model 500. 0- COMMONWEALTH. E.E.C., USA, MIDDLE EAST, etc. 60V; 0-0.5Amps. Current Limiting. Metered. P&P P&P and VAT extra Send for our questionnaire which, when completed, enables us to post quota- tions by return. £7 £40 VARIAC 5 AMP. Input 240V; Output 0-265V. This Cased. P&P £7 IS A VERY SMALL SAMPLE 0F STOCK, Or CROYDON RESISTANCE BOX MANAGIN 0.1 SAE TelephoneP for LISTS - Please check availability -1111 Ohms (4decade) Un -used. P&P £7... £25 before ordering. Carriage all units £10 VAT to be added to Total of Goods & E. A. Sowter Ltd All above Instruments in Working Order and Carriage Supplied with Manual (' No Manual) Manufacturers and Designers - E. A. SOWTER LTD. (Established 1941) : Reg. No. England 303990 The Boat Yard, Cullingham Road, Ipswich IPI 2EG, Suffolk STEWART OF READING P.O. Box 36, Ipswich, IPt 2EL, England Phone: 0473 52794 end 0473 219390 '"" 110 WYKEHAM ROAD, READING, BERKS RG6 1 PL e_ Telex 987703G Sowter Telephone: 0734 68041 Callers welcome 9 a.m. to 5.30 p.m. Monday to Saturday inclusive CIRCLE 115 FOR FURTHER DETAILS. CIRCLE 73 FOR FURTHER DETAILS. 76 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com RAEDEK ELECTRONICS SERVICING THE TELECOMMUNICATIONS AND ELECTRONICS INDUSTRIES

102 PRIORY ROAD, SCRIBERS LANE, HALL GREEN, BIRMINGHAM B28 OTB TEL: 021-474 6000 TELEX 311033 CHACOM-G Atn: CROSAL VALVES - National, Varian, Mullard, RCA, ITT ...

42426 26.50 EF80 2.75 53.5441 21.50 20394 18.00 6646 1.60 6164 3.00 12EC1 1.0 5763 4.50 7203 (547) 39.50 AH205 70800 EF85 4.70 515550 90.00 2C39WA 39.40 6848.5 275 6165 100 7501 2.80 57% 29.50 7203 (EIN) 49.00 3.00 482114 85.00 EFB6 2.60 5155538 375.00 2021 2.80 68E6 1.90 61B6A 3.65 6341 12.00 5814 7233 6.75 AH221 48.00 EF89 2.30 515750 (5101E) 23.80 2E26 750 6846 2.00 61064 4.20 9001 3.50 58225 X0.00 7234 72.50 12.00 AH238 35.00 EF91 2.95 5118II4 29.50 2142 95.50 6BJ6 125 6JE6C 4.95 90CG 12.00 5817 7217 3.20 AH2511 90.00 EF92 2.20 NT2 2.50 2155 225.00 6BK4C 415 82664 3.85 90CV 11.20 58664 112.00 7262A 26.00 120.00 442532 31.50 EF93 1.60 PCL305 1.85 2K25 111.00 6616 68.50 6,1148 6.20 15062 6.50 58674 7289 39.01 170.00 AJ2256 7.50 EF91 1.60 PL509 550 3300Z 82.00 8611074 3.60 6JK6 2.20 15002 3.10 5866 7308 7.50 BD512A 31.50 EF95 2.70 PL519 575 35002 79.50 6618 2.20 61648 3.95 15003 495 5869 1000 7322 801.00 8K66 90.00 EF183 2.75 QQV02ó 19.50 3828 1500 68646 93.95 61S6C 3.95 15004 1.50 53701 20.60 7360 9.00 BK148 110.00 EF184 2.00 5.50 38524 3.00 68M8 3.60 6K6GT 2.75 212E 170.00 5870ST 20.00 746641 80.01 60182 485.00 EFL20 2.95 0 0003-12 0 50 38W2 300 6658 3.75 6K8 1.85 2904 115000 58764 21.60 7527 73.30 BK481 111.0 EK90 1.90 503ó5 52.50 3C23 23.75 6805 2.95 6(11 2.55 3504 22.50 5879 3.90 75274 110.01 BK486 375.00 EL31 3.50 Q03125 49.00 3045 24.50 B6R8A 2.95 6KD6 5.90 3506 22.50 5896 14.90 7531 23.50 11.25 6K4864 525.00 EL36 2.30 004.250 59.00 3CX10045 39.0 6606 2.75 6(08 2.00 5726 34.50 58944 7543 201 5754 35.00 45.00 BK7703 250.00 E178 4.95 R1169 80.00 300100847 495.00 6BZ6 2.50 6068 3.90 58910 7551 5.50 815 18.50 6.50 8.00 BLT119 320.60 EL81 10.95 RG31250 35.00 3CX150047 398.00 601 1.85 6KG6 6.00 5920 7558 BT5 51.50 EL83 11.50 RG32504 15.50 4ó5A 52.50 6044 1.65 6KM8 3.50 710 29.90 5963 1.90 75814 18.25 6T58 5150 ELM 2.95 RGI-1250 18.00 4-1254 57.00 6047 3.50 6(58 5.50 7401 66.80 5965 2.29 7586 11.50 6TI7 152.00 EL86 2.80 RG4-300 90.00 4-2504 76.0 6C6&1 190 6(X8 8.00 780P 103.50 5991 20.00 7587 38.10 805 42.00 6005 1.90 87174 142.00 E191 9.10 6M126 1360.00 4100A 80.00 6CF6 1.90 613GC 3.50 75914 5.03 2.90 BT19 36.00 E1360 795 RR3250 15.00 41008 13.30 6057 2.25 616 METAL 15.00 807 6011 29.90 77235E 28.65 8189 295.00 EL500 2.90 RR31250 34.50 FOOL 86.00 6016 9.95 6114 4.95 810 50.00 6012 9.90 77354 26.01 811A 11.90 5011 20.00 BT95 129.90 E1503 39.00 6888A 12.00 1832 34.50 8CJ3 2.30 6158 2.00 781501 GE 48.01 812A 19.90 6021 3.70 67125 72.50 E1505 6.00 54075 195.00 1C35Á 8500 BCJ6 10.95 6108 1.95 78156 AL 18.00 10.50 BT127 95.00 EL519 6.75 51076 215.00 ICX25tIB 6CK6 11.50 6M11 4.80 813 1545 28.50 6058 7868 1.20 3.70 C1K 20.00 EM 9.95 51092 195.00 IEIM/AMPI 19.00 6016 3.30 6MJ8 3.50 813 IRCA) 85.00 6063 7903 115.01 C3J 22.50 EL303S 9.95 51102 210.00 40X2508 INATI 80345 2.30 6011 2.55 8298 17.20 6065 725 7905 13.50 C3JA 29.80 EL821 9.95 51113 220.00 39.50 BCN6 1.95 6547 3.00 8334 61.50 6073 5.50 7984 13.50 10.00 C3JL 30.00 EM84 2.00 SC1/40 5.00 40X3504 15M1 70.03 8006 2.211 6SL7GT 1.95 843 6080 120 8008 18.80 C16J 120.00 E532 16.25 SK410 29.50 4CX3504 IAMP) 6CW4 6.50 8S57GT6 2.85 815 18.30 6083 72.00 8020 35.01 13.10 C01907 17.70 EN91 2.80 SK800 16.50 68.00 6CW5 2.80 6Sß7 3.80 8576 708.00 8064 8092 8.20 CK5687WA 4.10 E592 3.30 S1(8004 19.50 40X350F 720 6005 3.80 603 1.50 8664 15.50 6085 8.60 8056 15.01 420.00 01016 18.00 F735 1.85 SKfi06 7.50 4CX15034 110.00 6CY7 3.00 6284 200 868 24.00 60944 8068 1301 19.00 DQ4 31.50 Q41 2.45 SK850 32.00 4C01500B 370.00 6CZ5 3.15 604 1.95 8724 6101 2.20 8072 89.20 12.50 21.50 062010 1.80 EZ80 1.95 SP41 3.60 4CX10oo00 6048 2.30 6VBGT 1.95 922 6130 8117 165.01 17.80 7.50 DR2160 750 EZ81 165 SSR-13 120 785.0 8006 2.45 604 2.00 927 61484 8121 90.00 14.70 7.50 DR2110 9.00 EZ90 2.00 T160L 34.50 4021 57.00 6008 1.50 BX5GT 1.85 930 61486 8122 90.00 18.50 49.00 DX453 12.00 F517 21.50 T29884D0 589.00 4032 6435 6018 2.00 60.8.6 3.00 931A 6155 8163 8201 DX4534 17.50 FG105 95.00 TB2 Y300 112.00 /PRBOC 250.00 6DK6 3.95 629 2.95 931B 25.00 6156 59.00 8164 332.00 631 18.80 61596 12.50 DX555 96.00 GX1.11 15.00 10550 125.00 401504 42.50 6035 2.30 167 8.50 8233 1.01 35.80 6201 6.50 0151 1.85 GXU4 37.50 1.11.15 25.00 55004 225.00 6DW48 230 1K7 10.85 935 8278 39.00 10510 110.00 1295 E551 44.0 GXUS 120.00 016831 14.50 5484 3.50 605 1.20 8067 2.00 6227 82984 1.50 10526 111.0 6267 2.60 75.60 EBOCC 14.00 GZ31 3.50 VR75 5.15 5401.5 2.50 6E48 2.45 8F07 2.00 8321101M) 2050 2.85 6293 14.00 E80F 13.10 KT66 6.90 06150 495 58251M 24.00 6E115 1.85 9SP4 88.00 61211(AMP) 68.00 2.85 5.50 15.70 E801 12.95 KT77 8.15 XC12 1.30 5022 123.00 6EH7 2.75 12476 130 20504 63604 8416 1690.00 E81CC 3.20 KT88 1595 001-2500 51.50 50015004 535.60 6EJ7 2.00 12417 1.90 /532U 250.00 6126 8117 555 215.00 18.00 E88CC 390 KU72Z 280.00 062-50 36.00 5022 76.0 6EL4A 1.15 12406 2.00 48336 6142 8422 20.00 4818 25.00 12.00 E886 925 15017 890,0 062-6400 1520 564 6.00 6E58 2.10 124074 1.60 6481 8436 80.60 18.00 E90CC 8.50 M8223 550 065-500 24.50 5R4074/6 375 fiEVI 2.85 12ÁV6 2.00 4875U 215.00 6528 8511 33.01 14.50 7.25 E92CC 6.50 648224 5.95 051275 137.00 5R4WGB 17.90 6E3.86 3.00 124X7 1.80 5517 6550A 8552 8.20 12.50 E1301 23.50 M01901 10.00 001276 269.00 5SR8 6.00 6FG6 2.00 12AX7WA 4.80 5544 6886 8.50 8553 280.03 E1860 8.50 M17815 96.00 X131-16004 29.50 51.1108 2.50 6548 16.50 12644 2.90 5515 95.00 6689 9.25 8808 27.50 110.00 9000 E188CC 750 M18536 220.0 061-320 72.50 SUPI 40.0 6517 2.25 12648 2.00 5551A 6693 8643 68.70 55524 8779 19.50 E5070 27.50 ML/3711 215.0 061-8100 95,0 50404 2.75 6FS5 2.25 12647 3.0 144.0 8751 1735 5557 21.50 6856 52.50 E891 1.95 MU7235 86.0 06028 69.40 52101 1.90 6085 2.80 128E6 3.00 8791 233000 EBC91 1.30 NIB8/ 44.50 2803U 19.50 6486 3.50 66E5 2.90 1266474 2.50 5559 51.50 6857 66.80 8814 23.0 16.85 9120 EBF89 1.50 518841 50.0 ZT1011 29.50 64J8 2.50 6GF5 2.10 12BY74 2.40 5581 6858 8874 165.0 103.50 EC90 1.85 NL601 86.50 20100551 13.50 6AK5 2.70 6GH8A 180 12BZ6 3.70 5582 21.0 6859 890641 55.0 20.65 8.20 ECC32 2.50 516641 130.50 ZM100 18.15 61K5W 2.90 6GJ5A 3.0 12DK6 1.50 5583 68838 8908 10.50 21.50 3.90 ECC40 12.10 51676 162.0 ZM101 18.15 6ÁK6 1.95 6GJ7 1.85 12DW7 1.25 5832 6922 8950 9.50 19.50 ECC70 3.70 51714 29.90 ZM1020 15.65 6415 1.95 BGK6 1.95 12E1 25.0 5636 7.0 6939 901 6.0 5642 8.70 6973 3.70 ECC/31 1.60 51740 52.50 042 3.10 6415W 1.90 6GW8 3.90 12608 12.0 9677M 31.0 ECC82 1.60 517400 66.80 0A2WA 5.50 641.15 9.10 66X6 3.0 126574 4.0 5644 17.0 6975 66.0 98444 420.0 2.85 7011 ECC83 1.60 5170 99.29 043 5.15 64M6 2.95 6606 3.0 121(76T 1.80 5651 1.50 9950 40.00 ECC85 2.20 51760 103.50 OB2 3.95 6.558.5 2.70 668 3.0 12SL7GT 3.95 5851 2.90 7015 50.0 16411 118.0 120.0 EC88 2.00 5140 17.35 0B2WA 595 64054 1.95 BHAB 3.05 13E1 155.0 5865 7017 66.50 2.75 7018 18.50 80091 3.0 511343 17.70 OB3 2.50 6Á05W 1.90 6868 3.05 20PE11 25.0 5670 ECC189 2.10 5110224 30.0 OC3 2.50 6408 2.29 6HE5 1.0 23PE13A 21.0 5684 28.80 7022 66.90 ECF80 2.20 511038 150.0 OD3 4.95 6AR5 12.90 6HF5 3.85 20PE11 25.0 58845E 39.50 7023 101.50 fCF86 2.50 5110524 144.0 16214 10.0 6456 5.50 61105 1.95 20PE15 22000 5896 3.30 7025 2.50 6.20 7027 ECF801 1.85 511020 144.01 10354 38.0 8.4570 7.20 61168 2.50 20PE19 25.0 5718 480 1.80 7034 42.50 601181 2.50 5110614 485.0 16634 62.0 6AU58T 450 6HS6 3.95 20PE20 27.50 5716 ECL82 3.60 511025 21.0 18638 58.0 8ÁU64 1.80 6826 2.75 21126 3.10 5727 20 7056 2.50 115.0 iC133 2.50 512923 525.0 IP21 104.50 6AV6 2.55 625 3.15 301506 5.0 5749 2.50 7136 ECL86 3.90 513140 19.20 1P29 30.0 BANTA 2.65 6J5GT 2.95 10(66 550 5750 1.90 7189A 2.10 3540 8.50 5151434 23.90 245154 21.10 BAZB 3.80 816 2.20 10(G6Á 5.75 5751 3.30 7199 4.20

R. F. POWER TRANSISTORS - Many other types available on request SD1202 7.50 SD1212-4 6.00 2N3375 11.30 2SC644 0.25 2SC1176 18.00 2SC1967 15.00 BER91 2.00 MRF245 30.00 MRF648 30.85 PT9847 16.00 SD1212-7 4.00 253553 200 2SC884 0.28 2SC1209D 0.64 2SC1968 17.50 BER96 2.00 MRF247 30.10 MRF750 6.50 SD1005 8.20 SD1214 8.70 2N3632 10.00 2SC703 36.00 2SC1213A 0.40 2SC1968A 22.00 BFY90 150 MRF260 5.50 MRF846 46.00 S01008 2.10 SD1216 11.00 253733 13.20 2SC710 0.45 2SC1213C 0.40 2SC1969 3.20 BLW29 10.00 MR6264 11.00 MRF901 2.75 SD1012-3 10.00 SD1219 18.00 1219-4 18.00 2N3866 1.20 2SC7100 0.28 2SC1239 2.50 2SC1970 1.50 BLW60C 15.00 MRF309 42.00 MRF904 2.95 S01012-4 10. 50 S D 253926 11.26 2SC715D 0.40 2SC1241 15.00 2SC1971 4.00 BLW60CF 15.00 MRF316 55.00 MRF91 1 2.50 601013 10.00 501220-1 9.50 2N3927 11.82 2SC715E 0.40 2SC1251 10.00 2SC1972 11.00 BLW64C3 65.00 MRF317 73.00 MRF5175 22.50 501014-6 10.50 SD1222-5 11.00 254416 0.75 2SC717P 0.38 2SC1260 1.11 2SC19713 7.50 B1W78 61.80 MRF321 35.00 MR F5176 30.00 501015 17.50 SD1222-STUD MRF5177 43.00 SD1018-6 13.00 11.00 2N4427 1.20 2SC730 4.10 2SC1303 5.00 2SC2001 0.45 BLWBO 10.25 MRF323 35.00 255090 13.90 2SC731 3.95 2SC1306 1.00 2SC2026 0.75 81W81 14.90 MRF326 63.00 MRF8004 2.00 SD1019 23.10 SD1224-2 13.00 10.95 255109 2.25 2SC732 0.25 2SC1307 1.50 2SC2053 0.80 81W90 13.00 MRF327 70.00 PT3134A 1.50 501019-5 23.10 601229-F1 255160 4.80 2SC741 2.50 2SC1311 0.40 2SC2097 36.00 BLW98 110.00 MRF329 58.06 P131348 2.75 SD1020 1.50 SD1229-STUD 255190 1.50 2SC821 6.60 2SC1311E 0.32 2SC2099 15.00 BLX39 13.75 MRF412 18.51 PT3134C 12.00 SD1074 16.10 10.95 12.75 255589 6.00 2SC288 0.30 25C1314 25.00 26C2100 24.00 BLX65 2.45 MRF421 36.85 PT31340 12.50 SD1076 18.50 001244-6 255590 8.50 2SC29B 0.25 2SC1316 0.40 2SC2103 18.00 BLX67C 9.50 MRF422 42.00 PT3134E 30.00 801077 1.60 001256 6.95 255591 8.90 2SC890 8.50 2SC13688 1.00 2SC2105 15.00 BLX67CF 9.50 MRF426 23.00 PT3161A 1.75 SD1078 26.50 001262 15.00 255643 13.00 2SC891 18.00 2SC1383B 0.50 2SC2116 160 BLX68C3 10.00 MRF4274 21.00 PT31618 1.75 SD1080 1.55 SD1270 3.75 255913 2.50 2SC900 0.18 2SC1424 1.35 2SC2118 9.00 BLX68CF 10.50 MRF428 57.00 PT3161C 8.50 SD1080-6 7.50 SD1272 10.95 2SC900F 0.19 26C1509 6.00 2SC2221 5.50 BLX694 20.00 MRF428A 75.00 PT3161D 14.00 SD1080-7 7.50 SD1272-2 1095 2N5945 10.90 13.75 255946 15.63 2SC908 4.50 2SC1546 0.45 2SC2233 0.90 BLX94A 36.00 MRF433 16.21 PT3161F 30.00 SD1068 26.00 SD1278 2SC9'1A 18.00 2SC1568 0.45 2SC2237 16.00 BLX98 132.00 MRF449A 10.50 PT3503 6.95 SD1089 28.50 SD1278-1 13.75 256080 6.00 12.75 256081 8.75 260345 0.21 2SC1589 5.00 2SC2281 13.00 BLY87C 7.50 MRF450 11.90 PT42614 16.00 SD1098 40.10 SD1285 1.25 256082 9.00 2SC945R 021 2SC1622 0.33 2SC2283 9.00 BLY88C 11.00 MRF453 14.00 P142618 24.00 SD11152 7.50 SD1300 256083 12.00 2SC952 0.60 2SC1623 0.30 2SC2287 1130 81.0880F 11.00 MRF453A 14.00 PT4261C 60.00 SDI 115-7 2.10 SD1303 2.50 256084 13.20 2SC982 0.30 2SC1688 16.68 2SC2289 12.50 BLY89C 13.00 MRF454 21.00 PT43160 12.00 SD1127 2.50 S01316 2.10 8.00 2SC994 2.50 2SC1674 0.25 2SC2290 27.50 8LY90 45.00 MRF454A 24.00 P14316D 18.00 SD1131 3.25 SD1317 8.00 256094 21.00 256095 8.50 28C998 3.90 2SC1675 0.20 2SC2347 0.30 BLY91CF 11.00 MRF455 16.00 PT4316E 25.00 SD1133 950 SD1405 2SC1001 9.90 2SC1678 1.25 2SC2369 2.00 BLY94 45.00 MRF455A 21.00 PT4316F 30.00 501133-1 10.00 S01407 27.50 256255 3.45 55.00 2SC382 0.65 2SC1011 15.00 2SC1729 18.00 2SC2370A 18.00 MRF208 12.00 MRF458 19.95 PT5661C 14.00 S011341 2.50 501407MP 5D1410 19.65 2S04513 0.22 2SC1070 1.15 2SC1730 0.25 2SC2379 15.00 MRF212 12.00 MRF466 24.50 PT6751 24.00 S01134-2 10.00 10.00 21.00 2SC4588 0.36 2SC10961 0.90 2SC17400 0.20 2SC2395 15.00 MRF221 12.05 MRF472 4.40 P118820 15.00 6011348 501410-1 2.20 21.00 2SC4561C 0.22 2SC1096M 0.90 2SC1765 7.75 2SC2407 1.00 MRF229 3.50 MRF476 PY8831 2.75 SD1134STUD S01410-3 2SC460 0.25 2SC1'17 E1.50 2SC1815Y 0.28 2SC2420 18.00 MRF231 12.36 MRF475 4.201 7T8837 10.00 7.10 SD1412 36.00 10.25 2SC4606 0.25 2SC1120 12.50 2SC1906 0.33 2SC2494 16.00 MRF232 13.50 MRF477 12.50 PT8838 15.00 SD1135 SD1412-3 24.00 18.00 2SC4616 025 2SC1121 24.00 2SC1907 0.30 2SC2509 6.00 MRF233 14.30 MRF492 27.50 7T88548 18.00 S01135-3 12.00 001413 11.70 36.00 2SC535 0.38 2SC1122 18.00 2SC1945 3.50 2SC2531 1.30 MRF234 16.00 MRF497 18.50 PT8861A 15.00 SD1136 601414 33.00 2SC535A 0.36 2SC11628 0.90 2SC1946 18.75 2SC2538 1.10 MRF237 3.10 MRF515 2.60 PT8864A 30.00 SD1143 9.45 501416 S 10.00 D 1418 30.00 2SC5356 0.38 2SC1165 6.95 2SC1946A 16.50 2SC2539 15.00 MRF238 12.60 MRF517 3.50 PT8874 18.00 D 1143-1 S 2.50 SD1421 36.00 2SC535C 0.35 2SC1'69 4.85 2SC1947 9.88 2SC2540 24.95 MRF239 20.00 MRF620 18.00 P19795 12.50 SD1144-1 2SC540 14.95 2SC1176 14.00 2SC1955 7.20 2SC2545E 0.29 MRF240 18.80 MR161 25.70 PT9797 14.00 601158 7.95 SD1428 24.00 2SC608 0.75 2SC1'77 17.25 2SC1966 11.00 BER90 1.50 MRF243 35.00 MRF646 26.20 PT9841 16.00 S01201 7.35 S01429 1198

TERMS: C.O.W. POSTAGE/PACKING: Add f1 to order under 150 value. VAT All prices are excluding VAT, please add 15% to order and postage. GUARANTEE: All goods are of current production and solo with manufacturer's warranty. ENQUIRIES: Are welcomed for other types/brands of valves. Please send SAE

CIRCLE 40 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MARCH 1985 îî

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cassette have very computer - sounding noises, not too Music on the BBC Micro dissimilar to those available on the BBC's own internal sound generator, even when more Music 500 than three voices and stereo positioning A virtually unlimited variety of are used. So the synthesizer is fully waveforms and envelopes are not demonstrated except by available for playing on eight one's voices arranged over seven own trial and error methods. The is of high stereo positions in the Music sound output quality and is best transmitted 500, a synthesizer add-on for through hi-fi the BBC Microcomputer. The a good system but it could have been easy to hardware comes in a metal - cased box, roughly the same ' install a low -power audio shape and size as a floppy disc amplifier to give, for example, drive. It contains its own power .` headphone output. My supply. It connects to the computer is in a different room computer through a ribbon from my stereo equipment and . . initially I recorded the output on cable which plugs into the a 1MHz-bus port and has itself a portable stereo cassette player . before being parallel socket for that bus. The able to hear it. The . negative aspects of this review audio output is from a 5 -pin might be of a temporary nature; DIN socket and a stereo :rEnvelopes for the notes can is due to lack of any partly .the there has been mention of a amplifier must be connected to :be. defined in several ways from graphics facilities. Music can make the output audible. keyboard add-on for the Music a simple attack -decay-sustain - only be entered. as a computer 500. The present programming Supplied with the Music 500 release sequence to complex program through the computer language and rather poorly - is a cassette which includes geometrical and pitch -bending keyboard. Not, for example, as AMPLE, a music programming printed handbook make no envelopes. Waveforms and notes on a stave. There are reference to this so both must language, some examples of envelopes are assigned limited facilities to actually hear be updated when the keyboard preset waveforms and independantly to sound envelopes or the waveforms, is issued. The keyboard will envelopes and a selection of channels and may be used in tunes being produced without music produced by the system. also allow the synthesizer to be any combination. writing a program and then played 'live'. Music 500 was There is also a utility to enable Musically, notes are entered running it. There is no list of the programs to be transferred developed for Acorn by Hybrid using their letter names, specific waveforms or envelopes Technology Ltd., Acorn to disc. Ample works rather like familiar to musicians. The so that one could make the Forth. It enables commands to Computers Ltd., Fulbourn sequence 'CDEFGABC' would output sound like a trombone, a Road, Cherry Hinton, be defined in terms of existing play a C major scale. Sharps flute or an organ. The pre- words and these new words are Cambridge CB1 4JN. and flats are entered with a plus programmed examples on the EWW100 used in turn within the or minus sign before the note definitions of other words. and key signatures may be Eventually the whole program defined at the beginning of a A system for music Then two keys are used to executes on the command of a piece, after which only By way of contrast, The Music increase or decrease the value single word - 'play'. accidentals need to be entered. System (TMS) includes no of that parameter. There are 16 channels of One convention that takes some hardware and relies on the The Music Editor section of sound, normally used in pairs to getting used to is that upper- BBC's internal sound generator the software works rather like a allow a maximum of eight case letters are used for the and computer keyboard. For word -processor for music. voices. More channels can be next note above the current one £25 it offers two discs (also Entering music is by positioning assigned to a particular voice at but lower-case is used to available on cassette) and a one cursor at the note value and the expense of having fewer descend. 'AG' would play A handbook. The programs are all then moving a second cursor to voices. Each channel in a pair followed by the G above but Ag inter -linked through a menu the note position on the stave. can have its own waveform and would be used to play A page and it is possible to use Key and time signatures are the frequencies may be varied followed by the G below it. the Editor for entering music, entered at the beginning of a so that one channel will Hence, if we were to enter the Synthesizer module for piece and subsequent notes are modulate the other. `cdefgabc' instead of getting a creating new sounds, the automatically given the correct Programming words are scale, each note would be Keyboard programme for sharps and flats. As in Music available for frequency followed by the one a seventh playing `live' music. There is 500 there is automatic bar modulation, ring modulation below and that sequence would also a printer driver program to checking to ensure that the note and synchronized waveforms. descend about seven octaves! enable the printing of music values given to each bar agree Harmonics up to the 16th can The synthesizer has a pre-set scores and a 'linker' which with the time signature. The be assigned to a channel, each pitch which may be altered to allows seperately programmed music editor works on one voice with its own amplitude. The tune it to a different pitch. music to be strung together into at a time but may be switched wave is then converted to its Numbers are assigned to longer compositions. Each instantly to either of the other geometrical form for storage; relative note lengths and the section of the software is menu voices. Music may be entered the geometrical form can also speed of the music is governed driven and uses an icon system one voice at a time or be defined directly, without by a 'tempo' instruction. similar to that of, say the Apple in parallel, working on all voices harmonic analysis. A noise The language is very Macintosh, so that there is together by rapidly switching channel, to produce percussion comprehensive and it is hardly any need to type at the between them. The program sounds, is not directly available possible to reproduce almost keyboard at all. Typically a will position the cursor at the but can be simulated by any sound that can be cursor is used to point at an correct place when switching introducing a random element imagined; but it is also quite icon, or pictorial representation between voices. One facility into the waveform generation. difficult to learn and use. This of the parameter to be altered. which illustrates the 78 ELECTRONICS & WIRELESS WORLD MARCH 1985

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thoroughness of the program is clefs, key and time signatures, the provision for 'first time' and accidentals and bar lines appear 'second time' bars in a repeated as they would on conventionally section. Notes may be sounded printed music. as they are entered and sections All this is documented in the of a piece played at any time instruction manual which is during their development. very well laid out with all The Synthesizer module is an functions clearly illustrated. envelope generator and again is TMS also has its drawbacks; programmed graphically with a it only covers a range of four representation of the envelope octaves and is restricted to the shape on the screen. Pitch and envelope commands available to amplitude parameters can be the internal sound generator on easily changed at will and the BBC computer, The elements from one envelope can cassette version has fewer be transferred to another. Up to facilities than the disc, 30 envelopes can be stored especially in that it cannot use glass graded index type give a either in a form to be replayed the fourth (percussion) channel. FOR INTERFACE transmission distance of at least through the rest of TMS or to However the system is under FIBRES 1km. The company can also be incorporated into a Basic constant revision and there is mention of the extension of the provide the optical cables program. One p.c.b. offers both system with a music keyboard terminated at the required The Keyboard module allows transmission and reception of the and a Midi synthesizer. lengths or a termination kit for computer to be used as a serial data along an optical 'real time' So we have two very installation in the field, if instrument using the fibre. Although primarily contrasted systems; the Music required. Applications include QWERTY keys to play the notes intended for R9232C links, the 500 has superb but expensive installation in areas of high with envelopes previously interface can also be used with but the programming electrical interference, where defined in the Synthesizer hardware t.t.l. levels and R9422/3. Full language without any graphics optical cable can replace module. It is even possible to duplex facilities are available 'record' efforts a is quite difficult to use RS232C cables. Transmissions one's with set but the board may be used in of keys which will a compounded by the poorly are unaffected by r.f.i. and are emulate simplex mode if a separate produced but, we hope, free from lightning damage and tape recorder so that it is control signal is needed, such temporary manual. The Music are therefore very suitable for possible to 'rewind' the memory as the 'busy' signal from a System, at about £25, is at the installation in hazardous areas. and play-back or re-record a printer. Fibres are connected to section. A metronome icon opposite end of the scale with Arthur Ford Ltd., Park Lane the board by S.M.A. Works, Old Basford, ticks away in the corner of the excellent software. and a connectors. screen to preserve the tempo. manual that is very easy to use Nottingham NG6 OEU. of the 200 micron A piece so recorded can be but the system is restricted by Fibres EWW204 stored on tape or disc as a file. the hardware available on the bias and offset currents are as Finally the printout module will computer. Both systems are HIGH-SPEED OP -AMP low as 10nA and offset voltage enable music programmed into planned to be extended with is guaranteed to be less than the music editor to be printed live -performance keyboards and With the precision necessary for 601.V. The gain bandwidth out on a Epson or Star Delta TMS may get an external high fidelity audio equipment as product is 63MHz and the dot-matrix printer. It is possible synthesizer add-on. The Music well as signal conditioning in device is fully output short to print one voice at a time or System is based on programs instrumentation the Raytheon protected. Typical all voices together and there is orginally developes by System circuit OP -47 is a low -noise device, applications include low provision for a very high Software but has been extended available in a TO -99 metal can and enhanced in cooperation impedance microphone resolution print-out giving or an 8 -pin plastic dil package with Island Logic. System, 12 amplifiers, professional quality superb printed music or and in military or commercial Sheffield audio amplifiers, spectrum medium resolution which prints Collegiate Crescent, temperature ranges. much faster. Treble and bass S10 2BA. EWW101 analysers and precision Power -supply rejection and instrumentation amplifiers. common -mode rejection are Raytheon Semiconductors, typically 120dB with a spectral Ogilvie Road, High Wycombe, Voice 2 Rar 13 ilFr-ee space 293 )_ noise density of 3nV/Hz. Input Bucks HP12 3D9. EWW200 Polume 1p0®ID©ElOEIe El] 1Ell E17 EE 1 jEnvelope i _= 4 Op4?

TA 20°C .1111111 inn r y 4 g E G r , VA CL 110 111111111111111111 Mi I " ha. . i b . 4 h 30 IIISiIiIIIIIIIIIIIIIIIlil t ë a auto sound auto bar mi-m2 01 10 10 100 Load Resistance Ito ti

ELECTRONICS & WIRELESS WORLD MARCH 1985 79

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ETHERNET NODE ON A CHIPSET All the logic, protocol and control functions needed to implement the interfacing of a processor to a Ethernet network are incorporated in three chips from AMD. The devices are: 8990 network controller, 7991A serial interface adaptor and 7995 Ethernet transceiver. At the data link level the set supports buffer management, data encapsulation, framing and package control, c.r.c. generation and checking, and serial/deserialization. At the physical level, there is 10Mbit/s data rate. carrier-sense multiple access with collision detection and tranceiver interface compatibility. Dage (GB) Ltd, Eurosem Division, Rabans Lane, Aylesbury, Bucks HP12 3RG. through an interface, line and/ MULTI -STANDARD TAPE RECORDER or battery supply, will accept EWW106 reels up to the 14in. NAB to be Based on modular technology, designed easy to use and standard, six tape speeds and a the Stellavox TD9 tape recorder has claimed for it 'the highest variation control, inside or can cope with magnetic formats sound quality'. It may be outside oxide winding, a of 0.25in, 0.5in and 16mm film. quickly adapted to the required monitor speaker and it may be All tape transport functions are format. Amongst its features rack installed. There is a wide controlled by a microprocessor are: Synchronization, with, or variety of accessories. Future with feedback data from opto - without time -code for film or Film Developments, 114 electronic tensiometers. The video, a locator, pre -view Wardour Street, London W1V recorder is ergonomically facilities, computer control 3LP. EWW108 FLEXIBLE STORAGE SYSTEM A multipurpose data storage available to other disc images. Ram Tape -PC has its own system is designed for use with More than 30 double -sided, power supply, is provided with a 16 AMP P.C.B. the IBM-PC or other compatible double -density disc images can host adaptor card and a disc computers. The Ram Tape -PC be stored on the tape cartridge, containing the software drivers RELAY combines a 400Kbyte ram, which can be loaded from the and utilities to access the organised as a 'silicon disc', tape onto the electronic disc to various functions. Menu -driven Using Silver Cadmium Oxide with 13.5Mbytes of storage on a provide access speeds up to 50 software simplifies the operation contacts for long life, the Zettler in tape cartridge. The software times faster than with flexible for inexperienced users. Euro A2735 relay is 28mm high and configures the first part of the discs. The electronic disc may Electronics Ltd, Lancaster Gate will switch 16A at 250V a.c. ram as a double -sided disc with also be loaded from any other House, 319 Pinner Road, Normally supplied with one from the drive in the system to provide Harrow, Middlesex HAI. 4HF. changeover contact, the relay direct access computer. The remaining ram is the same rapid access. The EWW109 can handle up to 415V 3500VA. 100 000 operations are claimed at 250V/ 16A a.c. with pick-up and drop -out times of 7ms and 2ms respectively. High isolation between coils and contact is provided. Direct coil voltages can be selected from a range between 5 and 76V Normally open contacts can be supplied to special order. Sterling Components Ltd, Sterling Road, Slough, Berks. EWW107 ZETTLEia AZ 735-03-E 250164» GC I{ cv25r

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RESISTANCE BOXES whereas the precision box uses Two boxes offer decades of 350mW resistors with a resistors selected by dial maximum total voltage of 150V. switches which also indicate the Both are designed for value chosen. The 1065 box laboratory, industrial and offers power resistors over the academic use. range 0.1 to 120KQ, while 1066 They are housed in metal cases has precision wire -wound and are easily transportable. resistors for a range of 1 to Switch contact resistance has 1.2MQ decade and 0.01% for been kept to a minimum by the the others. The power resistors user of multi -wafer switches in the other box have an overall each with four parallel, silver- accuracy of 1% with the 0.1Q plated, self -wiping contacts. decade at 5%. These are 10W Time Electronics Ltd., Botany power rated and the box has a Industrial Estate, Tonbridge, maximum voltage of 500V d.c. Kent TN9 1RH. EWW203

PAGED requires. Messages are MESSAGES transmitted to the pager directly through Telex or Datel, or by A radiopager with the ability to telephone to a central display and store messages up radiopaging bureau, which will to 70 characters long has been forward the message through a launched by British Telecom. computerized system. Various Message Master can display options are available depending names and addresses, on whether the user wishes to telephone numbers, share use the Message Master in a PLUG-IN CIRCUIT BREAKER prices or travel information, and number of the 40 zones which Fitting a standard 13A socket fuse and is slim enough to fit up to ten messages with a total make up the national system. It and providing in turn a single two side -by -side in a double of up to 300 characters may be costs £75 a quarter and a futher 13A socket, the Power Breaker - socket. The Power Breaker is kept in the internal memory for £9 to use the bureau. 20 incorporates an residual available at a number of retail reference. When a message has British Telecom Radiopaging,. current circuit breaker shops and hardware stores and been received the pager will 4th Floor, 23 Howland Street, (r.c.c.b.) to provide a high at electrical wholesalers. bleep and flash a light, though it London W1P 6HQ. degree of protection against Suggested retail price is just may he muted if the user so EWW208 damage and electric shock. The under £20. B & R Electrical device is built in accordance Products Ltd., Temple Fields, to or read from in 1Oms with the relevant British Harlow, Essex CM20 2BG. 64K EEPROM conventional `Read' mode is Standards. It has a `power on' EWW205 Organized as an 8K byte device available as are a `deselected' indicator light, a test button and the HN58064P is an electrically mode and a low powered will cut out automatically if erasable and programmable rom `standby'. Different versions of plugged in to an incorrectly from Hitachi. It uses a single the device offer access times of wired socket, for example 5V supply. Latches are 250, 300 or 450ns. The device if the live and neutral provided on -chip for addresses is housed in a conventional 28 - wires are reversed. It and data. Depending on the pin plastic package. It is works on 220/240V status of the chip enable, specified to operate for over a.c. mains, incorporates output enable and write enable 10000 erase/write cycles. a 13A lines, six different modes of Hitachi Electronic Components operation can be selected: chip (UK) Ltd., 221 Station Road, erase takes about 20ms, Harrow, Middlesex HAI. 2XL. individual bytes can be writtin EWW 209

ELECTRONICS & WIRELESS WORLD MARCH 1985 SI

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DIGITAL THERMOMETER Claimed to be the smallest and cheapest hand-held electronic thermometer on the market, the Vixen is only 103mm long, costs less than £30 and is guaranteed for three years. It operates within a range of -120 to 820° with an accuracy of 0.2% and incoporates automatic cold -junction compensation. The thermometer uses NiCr/ NiAl, type K, thermocouples through a standard miniature connector, enabling many standard thermocouples from a variety of sources to be used. The device has a battery life of 6000 hours which is claimed to be the equivalent of over four IMAGE FRAME STORE FOR MICRO processor's memory map. years normal service life. The Additional circuitry is needed display indicates low battery A high -resolution video frame preference to a p.1.1. as the for use with other processors. and open -circuit thermocouple. store is provided by the Eltime store is only locked to the Applications include robotic A Fahrenheit version is Image III. The single p.c.b. incoming video for the duration vision, medical imaging, factory available. Vixen Hytech Ltd., may be used in conjunction with of one field and this enables the inspection and security 17 Amberley Road, Bostal a BBC micro, to capture and device to capture a field from surveillance. Additionally the Heath, London 9E2 09G. EWW display pictures in real time several different sources whose store can be used to capture 201 from any 625 or 525 -line video synch timings are not locked to pictures which arrive slowly source. The highest resolution each other and which may have such as weather satellite is 512 by 512 pixels stored in a different interlace scans, or pictures and ultrasonic scan 64Kbit dynamic ram. Every none at all. images. Thus a display can be pixel can be accessed and Software is provided with held steady without the need for altered by the assignment of up details of how to configure the a long -persistence c.r.t. As well to 64 grey -scale levels. If a system for different resolutions, as the BBC micro, versions are lower resolution is selected, the capture pictures and read or available for use with the Apple store can be partitioned to write to individual pixels. An and IBM PC. Image III costs retain multiple pictures, e.g. for additional board can provide a just under £2000. It was 256 by 256 resolution, four full frame, the equivalent of two developed at the BT Research pictures can be stored. Pictures fields. Three boards can be Laboratories and is from the same or different combined in parallel to give an manufactured under licence sources can be compared. RGB colour store. The board from BT by Eltime Ltd., Unit A gated oscillator is used to interfaces directly with any of D29, Maldon Industrial Estate, synchronize incoming frames to the 6800 series of processors Fullbridge, Maldon, Essex CM9 the store, this is used in and occupies iK in the host 7LP. EWW EWW202

COMMODORE MODEM standard of Prestel and radio tranceiver or c.b. set for modem is supplied with Micronet. The modem has a the radio transmission of data. cassette software which can be A 300 -Baud modem to plug plug to fit a BT telephone Switches are provided to select adapted to select the character directly into the user port of socket, though it is not BT local/on-line, Originate/answer, bit lengths, parity bits etc. as either a Commodore 64 or Vic approved, and includes a socket self test and full/half duplex. required. £49.50 inclusive from 20 home computer has been for the telephone which is used Leds indicate when the modem Intelnet Ltd., Unit C2, developed by Intelnet. It uses for dialling. It also has a jack is on-line and whether it is Faircharm Trading Estate, power drawn from the computer for connection with an amateur receiving or transmitting. The Creekside, London 9E8 3DX. and requires no external EWW206 supplies or batteries. Model s-.- 2074/V21 uses a 10 -pole switched capacitor filter i.c. to remove noise from the line and tNTELNET frequencies are very stable as Model 2064 y21 aooSboud Plug-in they are derived from crystal MODEM oscillators. It operates to 'LINE CCITT V21 recommended tones for data communication at 300 - Baud and may be used for inter - computer communication as well as commercial databases (Distel, Maplin, Estelle, for example) which operate the V21 standard. It is not compatible with the V23 82 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com QUALITY CO TKROMTS CRIoKLEWOOD! This list contains nly a OF which is constantly being quoted updated. T are for "one -offs" -quantity discounts by negotiation. Official orders from Schools, L D Colleges, Goods Dept etc welcomed. WE SPECIALISE IN CREDIT CARD PHONE CR ORDERS. A quick call will check stock position and current prices. Add 60p p&p + 15% VAT to all orders. All in -stock items despatched same day unless notified. 40 CRICKLEWOOD BROADWAY LONDON NA/V2 3 ET PRICES SUBJECT SEND FOR FREE TO CHANGE ¡ t9y_ CATALOGUE 01-452 0161/01-450 0995 TIx:914977

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BC213L 15p 8S521 491' ZTX752 45p PW06(600) LM391N80 UPC 1185 2030114 OOP 68/35V 21p 7441 39e 74LS109 45p 4002 229 558, 254427 130214 180 8Ú104 232P ZTX 753 47p 1 39p 175p 3959 305p 4PDT 37917

CIRCLE 20 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MARCH 1985 83

www.americanradiohistory.com LOW SERVICE BUSINESSI]IIFISM1i SYSTEMS LTD PRICES 5S, MAPLE DRIVE, EAST GRINSTEAD, WEST SUSSEX, PH19 3UR ADVICE

The PC -16 16 -bit computer provides PERFECT COMPAT BILITY 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 (640dots WINCHESTER DRIVE 12MB complete DRIVES - MEGABYTES FOR 128K £449 X 300 lines) £389 with controller £915 MICROPOUNDS! MOTHERBOARD'N', 8 -slot £329 12in HI-RES GREEN MON £89 IBM COMPATIBLE KEYBOARD (83 51" Half height 500 kB 40/80 £119 key) MULTIFUNCTION card with 128K 64K RAM EXTEND MODULE £59 £89 5i" Half height 1 MB 40/48 £125 (expandable to 256K) one PLL-port, DS/DD FLOPPY DRIVE (500 KB KEYTRONIC 5150 K/BOARD £175 51' Half height 1.6 MB 40/80 £159 one 5ER-port (2nd option) Clock/ unformatted £175 KEYTRONIC 5151 K/BOARD £210 51" Half height 2 MB 40/80 £199 Calendar with backup £259 WINCHESTER DRIVE SWITCHING POWER SUPPLY ....£105 3' Half height 500kB £119 MONOCHROME adaptor with CONTROLLER £425 ADD SERIAL PORT KIT £23 3' Half height 1 MB £125 printer port £239 512K RAM BOARD comes with FLOPPY DRIVE CONTROLLER ...£109 8' Full size 1.6 MB £309 - 8' Half size 1.6MB MULTI I/O CARD - one pll, one 128K RAM installed fully IBM £282 serial port, one games port, floppy compatible £299 MR521 Half height 12.75 MB Hard Disk drive controller, clock calender with unformatted £492 battery backup £299 All brand new, boxed, with bu,lt 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 CWO. DEALER ENQUIRES WELCOME. FOREIGN enquiries if possible by telex please. However, French & German speaking staff at your disposal. MONEY BACK GUARANTEE. SEND E1.00 for our latest catalogue of over 3000 items, computers, peripherals, consumables, robotics, etc CO JE,, TEL: (0342) 313427.24631/2 TLX: 257547:* CIRCLE 116 FOR FURTHER DETAILS. There are better ways of measuring hum, ripple and other small signals The Waugh Instruments Micro Amplifier extends the measurement mvatn/dv %um* Power aIVMa capabilities of your oscilloscope to 10011V/div from DC-2MHz 2 OnOita 2örc differential or single ended input. For details of thisand other iv" tx t0 &rtrWOc<° amplifiers contact: - 20 ele A Peter Waugh at Waugh Instruments, Otter House Weston Underwood, Olney, Bucks. MK46 5JS (0234) 712445.

CIRCLE 38 FOR FURTHER DETAILS. Toroidal VIDEO TERMINAL BOARD Transformers * 80 characters x 24 lines as manufacturers we are able to Requires ASCII encoded keyboard and monitor to offer a range of quality Toroidal make fully configurable intelligent Transformers at highly competitive terminal. Uses 6802 prices and fast delivery. micro and 6845 controller. Program and character generator (7 X 9 matrix with descenders) in two 2716 Mail Order Price List EPROMs. Full scrolling at 9600 baud with 8 switch 15VA 6.92 30VA 7.18. 50VA 8.86. 80VA 9.92. 120VA 10.59. 160VA 12.10. 225VA 13.69. 300VA 14.77. 500VA 19.20. 625VA 22.09. 750VA 26.17. 1KVA 38.82. 1.2KVA 44.06 selectable rates. RS232 interface. price includes p+p & vat. Available from stock in the following voltages: -6-0-6,9-0-9,12-0-12,15-0-15. Bare board with 2 EPROMS and program listing - 18-0-18,22-0-22. 25-0-25, 30-0-30,35-0-35,40-0-40,45-0-45,50-0- £48 plus VAT. Assembled and tested -£118 Send 50,110,220,240(max.10 amp). Primary 240 volt. for details or CWO to: Quantity Prices and delivery on request (we also manufacture conventional El type transformers) A M Electronics AIR,- Airlink Transformers. MA Wood Farm, Leiston, Suffolk IP164HT Unit 6, The Maltings, Station Road, ELECTRONICS Tel: 0728 831131 LINK Sawbridgeworth, Herts. Tel: 0279-724425. J CIRCLE 72 FOR FURTHER DETAILS. CIRCLE 53 FOR FURTHER DETAILS. 84 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com LANGREX SUPPLIES LTD House, Fallsbrook Rd., Streatham, London SW 16 6ED RSTClimax Tel:01-677 2424 Telex: 946708 RST

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Rl8 3.00 VL5631 15.00 5022 160.00 6F6 3.00 13E1 170.00 5727 7.05 AZ41 2.60 EABC80 1.25 EF8045 12.60 KT66 15.00 PCC 189 2.50 R19 9.24 XG1-2500 55.00 9180E 1650.00 6F23 1.44 19114 27.50 5749 2.50 BK448 111.90 EAC9I 3.50 EF8055 15.00 KT77 Gold P1212005 1.44 020 230 XG2-6400 SRIGY 3.50 6E28 1.60 19H5 17.50 5751 1.00 BK484 155.35 EAF42 2.50 E1190 1.75 uon 8200 P00006 1.60 RG3-250 32.68 111.90 5U4G 3.00 6F33 33.50 2489 67.25 5763 1.50 BS90 58.00 EAF801 2.00 EK90 1.50 KT88 Gold PCE82 2.00 RG3.250A 32.68 XG5-50 30.00 5U4G8 2.50 6H1 11.11 30015 2.00 5814A 4.00 BS810 60.00 EB41 1.00 EL32 2.50 Lion 20.00 PCF80 200 RG3-1250 59.50 X026400 5V40 2.50 6H2N 2.75 301217 2.00 5840 4.00 EB91 1.50 51.33 4.00 PCF82 130 30018 2.00 12.00 8T5 58.95 KTW6I 2.50 RG1-1250 61.60 162.00 5Y3GT 2.50 6H3N 2.75 5842 EBC33 230 EL34MU1 1.00 P12F86 2.50 30F5 1.60 5876A 31.50 BT17 151.00 KTW62 2.50 004-3000 99.45 XRI.1600A 5Z3 4.00 6H6 3.00 EBC41 2.50 ELM 2.50 PCF87 2.00 30FLI/2 1.38 5079 BT19 44.05 KTW63 2.50 553.250 40.00 53.75 5240 2.50 6J4 5.50 5.00 E8081 1.50 EIAI 2.60 PCF200 3.25 30FL12 1.00 5886 17.50 8T29 349.15 M8079 12.34 RR3-1250 45.75 XR1-3200 81.97 SZ4GT 2.50 6 6 0.93 58C90 1.25 ELA2 2.50 PCF201 3.25 30F111 2.00 8169 354.00 M8080 8.25 SIIE12 65.00 )(RI -3200A 6.301.2 1.75 6 7 4.75 5963 1.50 E13F80 1.50 30L1 1.50 gym EL91 5.25 9.02 PCF801 - 129.90 M8081 2.50 S130 6.00 XII -6400 6AB4 1.75 6 IN 2.S0 5965 3.50 EBF83 1.75 EL83 6.00 P121802 2.50 301.15 2.00 CBL31 4.00 M8082 5130P 6.00 165.00 6487 3.00 6K601 2.75 6005 2.25 E5189 1.50 E1.84 2.25 9.69 P12F805 1.70 301.17 2.00 6021 4.51 CL33 4.00 M008i 0.58 STV280-30 Y01120 395.00 6AC7 3.00 607 3.00 CY31 3.00 E8131 10.00 EL86 2.75 PCF806 1.70 14.00 YD1240 490.00 6AF4A 4.25 6K8 3.00 30P4 2.50 6057 10.23 EC90 1.25 EL90 2.25 M8091 10.43 PCF800 1.70 12.34 CI 20.00 M8096 STV280-80 Z759 25.00 6Á07 3.00 6KD6 7.00 40P19 2.11 6058 EC9I 8.00 EL91 f.N 6.01 PCL82 2.00 30PL1 3.M 6059 6.00 C3A 2200 M0097 21.00 ZMI000 0.00 6AH6 5.08 61.6Cr 3.00 E1292 1.75 EL95 2.00 8.10 PCL83 3.00 6AK5 5.99 30PL01 1.M 6061 6.00 C3JA 22.00 M8098 8.15 SU41 5.00 ZM1001 8.00 6L6GA 3.00 E12157 410.00 E1156 30.00 PCL&1 2.00 SU42 6AK6 2.50 30PLI5 1.11 6063 3.75 DAII 25.00 508099 10.00 ZMI020 9.00 6L6GC 3.50 ECC33 4.50 E1.360 8.50 8.00 PCL85 2.50 35W4 1.11 6064 0.50 0A42 18.70 MBI00 TD03-10 35.00 ZM1021 9.00 6AL5 1.S0 6L6GT 3.00 E121235 4.50 EL500/504 3.60 9.52 PCL86 2.50 50125 1.50 6067 10.23 0A101 1.75 M8136 10.23 TD03-10F 35.00 ZM1022 9.00 6AM4 4.44 61.7 2.50 E121240 5.50 E1.509 10.00 PC1805/85 2.50 7581 6.05 6072 6.11 DAF96 1.75 M8137 ]0.23 1T15 50.00 ZM1023 9.00 6AM5 9.N 6N2P 2.50 E121281 1.75 51921 13.00 P0500 6.00 75C1 4.50 6000 11.011DET24 0ET22 35.00 M8140 6.00 TT21 30.00 2M1040 19.36 6AM6 6.02 6N3P 3.50 5121282 1.75 51.822 13.97 PE0640N 45.00 31.50 4.75 05AI 7.50 6097A 235.08 49.00 M8141 6.50 Tr22 ZM1041 16.66 6ÁN5 6N7 3.11 ECC83 1.75 EM34 7.50 PFL200 2.50 60.00 85A2 6.45 60978 280.00 DF91 1.75 M8142 8.75 TT100 ZM1042 17.77 6ANBA 3.54 6P25 4.44 ECC84 1.75 5/480 2.50 PL36 2.50 TY2-125 65.00 3.11 2.25 90AG 12.96 6144* 8.25 DF96 1.75 M8144 7.50 I63GT 6AQ5 6Q7 3.75 ECC85 1.75 EMBI 2.50 PL81 1.75 TY4-400 80.00 90AV 12.96 61468 12.00 0091 1.75 MBI49 6.50 1824 25.60 6A06 0.66 6R7 3.25 ECC06 2.50 5M84 2.00 PL81A 2.00 TY4- 500 6AS7G 8.75 90C1 6.11 61598 19.00 0092 2.00 M8161 9.39 105.00 18354 N.M 65A7 3.00 0096 ECM 2.11 EM85 2.75 PL82 1.50 TY5-500 214.00 11363 64.00 6A16 1.25 tS5C7 11.51 6189 9.50 1.75 M8162 10.40 2.75 9 ECC89 2.60 EM07 2.50 PL83 2.50 TY6-800210.00 1.75 5.00 90CV 15.15 6201 11.40 01.92 2.00 M8163 0.25 IRS 6AU5GT 6SF7 2.50 ECC91 8.93 EN32 17.46 PL84 2.00 TY6-5000A 2.50 300 92A0 20.00 6442 20.00 0L94 1.75 M6190 155 1.75 6AU6 6SH7 ECC189 2.10 EN9I 6.50 5.00 PL5045 2.50 490.00 1.54 92AV 28.00 68838 8.25 DL% 1.75 M8195 10./5 114 1.75 6AV5GA 6517 3.25 51212807 1.75 EN92 6.96 P1.508 2.50 TY6-50008 1.50 9341 8.15 6973 4.00 DLSIO 14.00 M81% 7.50 2*S15 11.50 6AV6 65K7 3.50 DLS15 12.50 ECC808 3.00 EYSI 2.75 P1509 6.00 395.00 21239Á 44.00 6AX5GT 3.00 65K7GT 3.44 15082 6.50 7025 3.00 ECF00 1.50 EY81 2.50 7.60 PL519 6.00 TY6-5000W 70.80 667 3.25 15083 8.35 7551 6.25 DL516 12.50 M82122a 11.37 21243 6SN7GT 3.00 D1.S19 12.50 E12F82 1.50 E183 2.50 P1.001 1.50 425.00 2021 315 688 3.25 65 (27 3.40 150122 3.25 7586 15.00 ECF06 2.54 EY04 9.11 PL802 6.00 TY7-6000A 1.50 150124 6.4 7587 23.00 DM70 2.00 M8224 6.30 2E26 8.25 6BA6 6SR7 1.00 2.00 ECH35 3.M E186 1.75 PY33 2.30 525.00 2112 98.60 6847 5.80 2.75 211 35.4 7609 56.00 DM71 M822S 1.l0 6557 4.75 E120012 3.50 EY88 1.75 PY81 1.50 TY76000W 2J55 175.M 66ASA 1.11 3.50 723AB 125.80 7868 6.00 DM160 11.03 61250 E123481 3.08 EY500A 3.04 M8248 PY82 1.50 525.00 704 383;00 66124 1.N 803 25.00 7895 12.00 DY87 1.50 MD2901 115.00 2 6U8A 2.25 E123483 2.50 EY002 1.75 PY83 2.50 TZ40 25.00 005 IS.M 8005 IIO.N DY802 130 2.50 2 70B 336.00 68E6 1.50 6V6G1 2.25 E55L 45.00 ECH84 2.50 E235 1.75 MUI4 PY88 2.00 1218-20 3.50 1 25 125.00 68006 2.50 6X4 2.80 807 3.75 0068 11.04 ECL90 1.51 EZ40 2.50 MX119 55.4 PY500A 4.00 U19 13.75 }400Z 2.25 811A 1033 8122 100.00 E80CC 8.81 MX123 72.00 85.00 6816 6X501 1.75 ECLeI 1.75 0241 2.50 6,x,45 PY800 1.S0 U25 2.50 }500Z 85.00 61304 4.50 812* 29.30 8136 2.50 E8012F 11.27 56.70 7B7 2.50 ECL81 1.51 F241 1.50 PY801 1.50 U26 2.50 3A5 3.N 61316 85.00 7125 4.80 813 valve 65.00 8417 6.4 E80F 14.19 MXI51 17.25 13.73 6CI93 3.80 EZI1 1.50 QF451 /2.50 U37 12.00 3624 11.00 6BL7GT 1.50 2.51 033A 193.16 18042 11.53 E80L MX152 131.15 7C6 000 Z9 2.00 00V02-6 31.00 UABC80 1.25 3828 15.35 68506 115.00 704 7 1. M 866A 20.03 I8015 10.49E81CC 1'511 E0 50X161 151.25 KIM FW4500 3.50 UAF42 2.50 20.05 6BN6 2.00 872A 20.00 5811.13.27 ECUS1.54 50X163 20.25 00V03.1023.50 3829 7R7 4.25 E810F 35.48 E121.86 1.75 FW4-800 3.50 tJQV03-20A UBII 3.00 38240M 17.50 6BQ7A 3.50 7S7 3.50 922 6.00 Tested 50X144 25.52 931A 18.50 EF37A 5.00 35.00 18.38 UBC4I 2.25 6.00 7Y4 - E82CC 8.10 G1.37IK 147.60 3B241M 17.50 6807 2.25 5x-Eq9pasent E83CC 8.40 EF39 2.7S G551K 12.00 04X166 QQV06-40A 128109 1.50 3C23 25.00 68R0A 3.50 724 2.00 1624 4.00 412X2508 6.50 50.00 E140 500 17.50 MX168 .75.00 UC1281 1.75 6657 6.00 1625 3.50 E86C 8.25 G100.250 N7tl I5.00 3C45 24.50 11E3 55.80 CV Devices E88C 8.25 EF41 3.50 G240.20 12.00 pp V07-50 69.74 UCCBS 1.85 3CX100A5 68W6 1.00 12AH8 5.00 2050 5p Large stocks OA2 3 25 8.42 EF12 1.51 0100.1K 17.50 QQtn1206-404 UCF80 2.00 17.00 68W7 1.50 I.50 4212E 300.00 Prices on E8812 0A3 2.54 12A16 E90CC 9.47 EFSO 2.51 GN/ 75.00 UCH42 2.50 3E29 45.00 6BX7GT 5.M 12A17 1.75 4212H 300.00 application 11*.,, OA4 6.00 QU37 1230 UCH81 2.50 5544 81.97 E9OF 9.90 EF54 5.00 GNIA 9.60 081 135 304 2.01 6BZ6 2.75 124U6 2.50 E91H 6.25 EF55 3.51 GS16 16.41 QV0312 6.00 UCL82 L75 3V/ 1.75 1.25 124127 1.75 5545 145.04 083 2.50 QV04-7 6C4 E92CC 8.75 EFM 1.75 01112 15.00 3.50 UCL83 2.75 465A 44.60 6C96A 2.51 12AV6 2.50 5551A 114.90 9.10 EF83 1.80 GU50 24.00 035 QV08-100I7130 4.125* 44.00 5.00 12AV7 3.50 E99F 2.50 6CD6GA 5552A 155.35 GQ51 14.110INTEGRATED 7495 0.73 74136 0.51 74175 1.02 TBAS2OQ 2.30 CIRCUITS 7496 0.82 74141 4.80 74176 1.16 TBA530 1.98 7400 0.16 7423 0.33 7460 0.10 7497 3.15 74142 2.30 74178 1.36 TBA540Q 1.30 SADPI 55.08 VCR517B 10.00 7401 0.17 7425 0.30 7470 0.30 74100 1.54 74143 2.44 74179 1.36 TBASSOQ 3.22 BASES CRTs PI 10.00VCRSI7C 10.00 7402 0.17 7427 0.00 7472 0.33 74107 0.45 74144 2.60 74180 1.21 TBA56000 3.22 2AP1 B.50 SCPIA 00.00 7403 0.17 7428 0.43 7473 0.38 74109 0.73 74115 1.00 74190 1.90 18A673 1.20 B7Gutukirted 0.25 26P1 9.00 15.00 5 I5A 7404 0.18 7430 0.17 7474 0.38 74110 0.51 74147 2.00 74191 1.91 TBA700 1.52 87G skirted 0.35 38P1 13.00 SI1P7 25.00 7405 0.10 7432 0.30 7475 0.54 74111 0.71 74148 1.76 74192 1.90 TBA720Q 2.30 B9A unakined 3DPI 5.11 0.25 0G7-5 63.31 7406 4./3 7433 0.10 7476 0.42 74116 1.85 74150 1.80 74193 1.10 TBA75Q 2.07 B9A 3EG1 10.00 CRT sockets sinned 0.35 DG7-31 58.07 7407 0.43 7437 0.32 7480 0.56 74118 1.00 74151 0.94 74194 1.25 TBA80Ó 1.20 IntOcul 0.35 3FP7 6.00 Prices on 0.54 067-32 58.07 7400 0.20 7438 0.32 7482 0.75 74119 74154 1.80 - 74193 1.11 18A920 Loctd 0.55 3GP1 6.01 007-36 2.4 65.00 appGuuon 7409 0.20 7440 0.32 7483 1.00 74120 0.83 74155 0 90 74196 1.35 TBA920Q 2.90 Nuvistorbese 2.00 3 PI 0.00 13113-91 56.83 1/C sockets 7410 0.17 7441 0.90 7484 1.05 74121 0.43 74156 0.90 74197 1.35 184990Q 2.98 Valve screening 3 P2 8.00 0007-11 113.12 7412 0.29 7442 0.72 7486 0.39 74122 0.62 74157 0.75 71198 2.78 TCA270Q 2.90 si:es 0.40 3 P7 N.00 Texas can'saU VCR97 12.00 7413 0.32 74/7*50 1.17 7490 0.60 74123 1.18 74159 2.20 74199 2.30 TCA760A 1.38 3 PI 15.00 low profile VCRI38 12.00 7416 0.32 7450 0.18 7491 0.82 74125 0.58 74170 2.40 1M570 2.34 35.00 3511 VCR138A 12.50 8 pin 1051 7417 0.32 7451 1.18 7492 0.60 74126 0.58 74172 4.40 TM630S 3.50 20.00 3WPI VCR139A 0.00 14 pin 1051 7420 4.18 7453 0.18 7493 0.60 74128 1.63 74173 1.12 TM700 3.90 16 pin lOp 7422 0.20 7454 0.18 7494 0.82 74132 0.71 74174 1.60 TBA480Q 1.54

Terms of business: CWO. Postage end packing valves and semiconductors 50p per order. CRTs f1.50. Prices excluding VAT, add 15%. Telephone 01-677 2424/7 Price ruling at time of despatch. Telex 946708 those advertised. Prices correct when going to p ess. In some cases prices of Mullard and USA valves will be higher than E. & O.E. Account facilities available to approved companies with minimum order charge £10. Carriage and packing f1.'30 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 lifted. S.A.E. WWI CIRCLE 54 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MARCH 1985 85

www.americanradiohistory.com RRRRRRRR ¶CO1VIPUTER WBACANES . f THD ' ILADDIB' 8' OM OP COMPUTER AND ILICTROIIIO E SIP HOT LINE DATA EAU OMPOTIR aJS' All In one quality Computer rPa rRECHARGEA"LE 9ATTERIES cabinet with Integral switched Dry Flt Maintenance FREE by Sonnenschein. mode PSU, Mains filtering, and twin fan cooling. A300 07191318 12v 3 AH same a R8 891.770 NEW Originally made for the famous DEC POPS computer £13.98 A300 07191202 6.0.8 1.8 AH same as RS 891 DISTELdial up date bese Made to run 24 £4.99 Miniature PCB mount 3.8v 100 THE ORIGINAL FREE OF CHARGE system costing thousands of pounds 382 EX EQUIP bargeine. e Mah as R8 891.477 NEW £1.00 SAFT VR2C 1.2v "C" 1000'e of stock items and One off hours per day the PSU is fully screened and will deliver size NICADB In 18 cell ex equipment pack Good condition ON LINE NOW- 300 baud full du iexCCITTtones,8bit massive +6v DC et 17 amps, +18v DC at 1 amp and -18v is fully_ with , - easily spilt to single cells £10.50 + pp £1.90 word. no parity O1 DC et 6 amps, The complete unit enclosed -6t 1888 removable top lid filtering, trip switch, 'Power' and 'Run' LEDs mounted on Ali front panel, rear cable entries, etc. etc. Units are in good but used condition - supplied for EX -STOCK INTEGRATED CIRCUITS FILTERS and tech. man. MAINShang caused 240v operation complete with full circuit 2732 ex equip £3.28. 27128 - 250ns NEW £12.00. Cure those unnerving ups and data glitcnaa profeaelenal finish for Only 8118-200 £4,50. 8118-250 £3.98, by mains interference. Give your system that wide 15y8" deep 10.5" high. 8284LP-150 £22.00. 4184-200 £3.80, 4884-150 £4.00, 81215A As recommended by 2X81 news letter, matchbox £49.95 + Carr 1000 load 11.15 eDiim..t19" 11.5"d 4110-300, £1.20 2114 £1.75.8800 £2.80, 8821 £1.00, size up to watt hdFANS etc. Internal dim. 88A09 £8.00, 88809 £10.00, 881809E £14.80 L2127 compact completely cased unit with 3 pm fitted Alive availableea t LESSOPSU, 8 insurance £9.50. 08088AH-2 412,00, D8088 £20.00, 280A £2.99. socket U to 750 watts 55. 19"w. 18"d. 10.8"h. EIP IS. Carriage

ABLE BARRIER SHATTERED ON 16" Keep your hotV i PRICE with our range of BRAND NEW professional cooling fans ETRI 55X1J01 Dim. 92 x 92 x 26 mm. Rab CASED COLOUR MONITORS Miniature 240 v equipment fan complete with A scoop purchase from a major London Hotel enables us to offer this special finger Guard £9.96. converted DECCA 100 COLOUR video TV at a super low price of £99.0011 Low COULD J113AR Dim 3" x 3" x 2.5" compact modular construction, 18' high definition NEW VLSI enough to suit any budget!! Solid state very Quiet running 240 v operation. special modification micro PIL tube, which eliminates convergence problems and our own SUHLER 88.11.22. 8.18 v DC not seen on monitors miniature reversible fen Uses a brushleu results in 80 + column text definition and picture quality servo motor for extremehr high air flow, costing three times as much!! In fact we guarantee you will be delighted with this almost silent running and guaranteed 10,000 product, the quality has to be seen to be believed. Supplied complete end ready to hr life. Measures only 62 x 82 x 22 mm plug direct toe BBC MICRO COMPUTER or any other system with a TTL ROB Current coat £32.00. OUR PRICE ONLY output. Other features include internal audio amp and speaker, compact with data. £12.88 oompfete dimensions only. 52cm W x 34 H x 24 D, auto degaussing circuit, attractive teak MUFFIN -CENTAUR standard 4" x 4" x 1.25" fan suppled tested EX EOUIPMENT 240 v et +_ finished case. 30 day guarantee. £8.25 or 110 v et £4.96 Or BRAND NEW 240 v ONLY £99.00 + £10.00 CARR. at £10.50.1000% of other fans Ex Stock Also available unmodified complete with mod data (Mod costs less than £1 2.00) Eí0.00. li for Details. Poet is Packing on all fans £1.b 'T EPROM COPIERS SPECIAL 300 RAU F F BUDGET RANGE Another GIGANTIC purchase of these EX BRITISH TELECOM, BRAND VIDEO MONITORS The 2. The "Complete Tool - to make the FINAL amazing SOFTY NEW or little used 2B data modems allows US At a price YOU can afford, our range of EX kit" for copying, writing, modifying and luting and for YOU to join the exciting world of data monitors EPROMS of the 2516, 2716, 2532, 2732 REDUCTION, EQUIPMENT video 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 etc.ONL 195.00 Modulator, ZIF socket for data base, pre tested and set for up to 80 col use on pounds each, the 2B has all the standard requirements BBC micro. Even where MINOR screen 15 more!! "GANG OF EIGHT' intelligent Z80 controlled business or hobby communications. All this and burns MAY exist - normal data displays are gang programmer for ALL single 5v rail 300 baud full duplex" CALL, ANSWER and AUTO modes unaffected. i000,j EPROMS upto 27128. Will copy 8 27128 in Full remote control Standard RS232 serial interlace SOLD TO OATS typ. 3 MINUTES!! Internal LCD display high input. ONLY CCITT tone standards ONL " Built in test switching 12" KQM 320-321, bandwidth and checkingroutines for IDIOT PROOF NOW x lines. Supplied with full data 240v Mains operation will display up to 132 columns 25 operation. ONY1395.00 + 996300. ,£29.95 Housed in attractive full enclosed Modular ' 1 year full guarantee EIGHT PLUS" same spec. as construction 2 a only "GANG OF n1 Just 2 wireS to comma. line brushed alloy one, pi £32.95 above but with additional RS232 serial inter- Direct isolated connection OREEN screenEJ9, face for down line loading data from Computer Order now - while stocks last. Carriage and Ins. £10.00 24" KOM large screen black 8 white etc. ONLY 6 445.00 + P163.00. monitor fully enclosed in light alloy case. Data on request. sheets 2V a il E31grT oCarrialubs etc. 5Q SUPER PRINTER SCOOP ge £ 10.00 "RAND NEW The Do Everything Printer at a pprrice Met will cif ice NEVER be repeated. Standard CILNTRONfC5 DATA MODEMS NTRON S interlace tor connection °RIC, DRAGON etc. Superb ormt quality with lull revolution with 739-2 addressable Cdirect DEC CORNER Join the communications HIGH DEFINITION PROPhicaORTIONAL(S9ACED our super range of DATA MODEMS with MODE for WORD` PROCESSOR applicationsl 56132 PDP 1140 System comprising of CPU. prices and types to suit all applications colmuch single sprocket or Dali 124K memory + MMU 16 line RS232 and budgets!! more. v MdON aPLAY ELEcT110i! Cut nterface, RP02 40 MB hard disk drive. at the ridiculous price of INLra Hale + VAT Complete wltn Most modems are EX BRITISH ILr lull manual eta Limited quantity -Hurry white clocks last. TU10 9 track 800 BPI Mag tape drive. dual TELECOM and are made to the highest Options Interface able (lapedM for BBC, ORIC, rack system. VT52 VDU etc. etc. Tested standard for continuous use and reliability. el, -DRAGON RONICc pq £12.60 span ribbon and running £3750.00 RS232 interfaces are standard to all our £3.50 each BBC graphics amenscreen dump utility program Ca so modems, so will connect to ANY micro etc. Carriaoe and Ina £ 10.00 + VAT BA11-MB 3.5" Box, PSU, LTC £385.00 with an RS232 serial interface. DH11-AD 16 x RS232 DMA HUNDREDS OF interface £2100.00 DATEL 2B see SPECIAL OFFER centre of PRINTERS DLV11-J 4 x EIA interface £310.00 this ad. EX STOCK FROM £49.00. Call Sales Office for Details. DUP11 Sych. Serial data i/o £850.00 MODEM 13A, 300 baud. Compact unit only 00200 Dllog - multi RK 2" high and same size as telephone base. £495.00 Standard CCITT tones. CALL mode only. controller 1 large AO 3 pen drum plotter and Tested with data. ONLY E48.00 + 1114.80. only CALCOMP 1036 DZ11-B 8 line RS232 mux board £850.00 MODEM 20-1, 75-1200 baud. Compact unit offline 915 magtape controller. Good working order. LA36 Decwriter EIA or 20 ma loop £270.00 for use as subscriber end to PRESTEL, LAXX-NW LA180 RS232 serial interface MICRONET or TELECOM GOLD. Tested with £2500.00. and buffer option £130.00 data. £29.95 + 17E1.50. LAX34-AL LA34 tractor feed £85.00 MODEM 20.2. same as 20.1 but 1200-75 MS11-JP Unibus 32 kb Ram £80.00 baud 599.00. M811 -LB 128 TRANSDATA 307.9300 baud acoustic DISK DRIVE SPECIALS Unibus kb Ram £450.00 coupler. Brand new with RS232 interface. SIEMENS F_ DD -100.5 51/4" 40 track single sided. Ex new equipment tested, MS11-LD Unibus 256 kb Ram £850.00 195.00 + I 64.50. guarañtëed working. Complete with data£75.00 MSC4804 Obus (Equiv MSV11-LI DACOM D8L2123 Multi Standard Modem, SHUGART SA400 51/." 35 track, single sided, Ex equipment, guaranteed 256 kb £499.00 switchable CCITT or USA BELL 103 standard. working 655.00 PDP11 /05 Cpu, Ram, i/o, etc. £450.00 V21 300.300. V23 75-1200, V23 1200-75 or PDP11/40 Cpu, 124k MMU £1850.00 1200-1200 half SHUGART SA800, SA850 8" drives plus spares EX Stock call for prices. duplex. Hard RT11 ver. 3B documentation ka £70.00 Auto answer via MODEM or CPU. CALL or disk drives. RK05-J 2.5 Mb disk drives £850.00 ANSWER modes plus LED status indication. Large quantities of HARD DISK drives currently EX STOCK including: KLBJA PDP 8 async i/o £175.00 Dim 2.5" x 8.5''*9'. BRAND NEW fully DRE series 30 mb Front Load for DEC, NOVA etc FROM 4295.00 MISE PDP 8 Bootstrap option £75.00 ONLY F248.00 + 9914.50. DIABLO 44/DRE 4000 A, B 5+5 mb cartridge drive FROM £995.00 Made by SE LABS for BT this VT50 VDU and Keyboard - RuaranteedATEL 2412 CDC HAWK 5+5 mb cartridge drive as new condition FROM £795.00 two part unit is for synchronious data links at current loop £175.00 1200 or 2400 baud using 2780/3780 CDC 9782 80 mb DEC RM03 compatible FROM £2900.00 VT52 VDU with RS232 interface £250.00 protocol. Many features include Auto answer, PERTEC D3422 5+5 cartridge drive FROM £495.00 2 or 4 wire working etc etc. COST OVER Large quantities of spares and controllers available for S100, DEC, HONEYWELL, 1000's of EX STOCK spares for DEC £800. OUR PRICE (I55.00. DATA GENERAL. Call sales office for details. PDPS, PDPBA, PDP11 systems 8 DATE L 4800. RACAL MPS4800 hiqh speed IN HOUSE disk drive refurbishing service - call for competitive quotations!! peripherals. Call for details. All types of good condition F293.00 CARR 610.00 Computer equipment and spares wanted ADD VAT TO ALL PRICES for PROMPT CASH PAYMENT.

All prices quoted are for U.K. Mainland, paid cash with order in Pounds Sterling PLUS VAT. Minimum order value £2.00. : Minimum Credit Card order£ 10.00. Minimum BONA FIDE account orders from Government Depts., Schools, Universities and : established companies£20.00. Where post and packing not indicated please ADD £1.00 + VAT. Warehouse open Mon -Fri L. 11 9.30-5.30. Sat 10.30-5.30. We reserve the right to change prices and specifications without notice. Trade, Bulk and Export 'I Ç1 -To i19.1 f 32 Biggin Way, Upper Norwood, London SE1 XE L IL I I i U /V_ -1- Telephone 01-6/9 4414 Telex 27924 CIRCLE 89 FOR FURTHER DETAILS.

86 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com FRS - PRINTERS - PRINTERS - PRINTERS PRINTERS - PRINTERS - PRINTERS - PR/ SUPER DEAL? NO - SUPER STEAL!! GE MODEL 30 GE TERMIPRINTER The FABULOUS 25CPS TEC Starwriter f9 RANONSW pt ONLY£4 + 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- PRICE for a professional printer for direct A massive purchase of these desk top processor electronics has a printer -terminals enables us to offer you full DIABLO/OUME connection to your micro. The printer offer a interface with these quality 30 cps printers at a SUPER command compatability fractionn Of standard RS232 serial LOW PRICE against their original cost of and full control via CPM Wordstar etc. its original switchable rates of 110, 200 and 300 over £ 1000. Unit comprises of full OWERTY, 'Many other features include bi directional COSt. baud. Upper and lower case characters electronic keyboard and printer mech with printing, switchable 10 or 12 pitch, full width 381,mm paper handling with 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 butter, standard RS232 serial interlace with hands take. fed paper from enables full width - up to 13.5" 120 column standard fan fold sprocket paper, upper - lower case, standard RS232 Supplied absolutly BRAND NEW with 90 day guarantee a td FREE daisy wheel 4" to 9.5". Many other features such as for more informatics. serial interface, internal vertical and and dust cover. Order NOW or contact sales office numeric keypad, electronic keyboard, auto horizontal ribbon Optional extras RS232 data cable £10.00. Tech manual £7.50. Tractor feed tab settings, standard motor on/off and FREE floor stand. adjustable baud rates quiet operation plus £140.00. Spare daisy wheel £3.00 Carriage & Ins. (UK Mainland) £1C.00. Supplied in good S/H working condition - many other features. supplied complete with manual. working with manual ONLY E95.00 Guaranteed 11*00 or complete untested 05.00, optional floor stand £ 12.50 PROFESSIONAL NEY8OARD OFFER CARRIAGE 6 INS. 110.00 Carr &Ins £10.00. An advantageous purchase of brand new surplus allows a great OWERTY, full travel, chassis keyboard offer at fractions of their ongmal costs. i ALPHAMERIC 7204/60 full ASCII 60 key upper, lower + control key, parallel TTL output plus strobe. Dim t 2" x 6' +5 & -12 DC. L,,.50. EXTEL PRINTERSTELETYPEASR33 , DEC LA34 Uncoded keyboard with 67 quality, GOLD, normally open swr ches on EX NEWS SERVICE compact, quality I/0 TEREITNALS I ;:'. `4"' standard X, Y matrix. Complete with 3 LED indicators 8 i/o cable - ideal micro E + + conversions etc pcb DIM 15- x 4.5" MPS Carriage on keyboards C3.0). built 50 column matrix printer, type AE11. FROM l95 CAR VAT Unit operates on 5 BIT BAUDOT code Fully fledged industry standard ASR33 data from current loop, RS232 or TTL serial terminal. Many features including ASCII TS interlaces. May be connected direct to keyboard and printer for data I/O auto data 110 EQUIPMENT micro, or comms receiver via simple filter detect circuitry. RS232 serial interface. 8 bit paper tape punch and reader for purchasing programme which enables us to bring you the best possible network to enable printing of most world baud, Due toour massive bulk off line and ridiculously s, s, Sub -assemblies. data preparation bargains. we have thousands of I.0 s, Transistors, Relays, Cap P.C.B wide NEWS, TELEX and RTTY services. cheap and reliable data storage. Supplied in surplus to our requirements. Because we don't have sufficent stocks of any Switches. etc. etc. Supplied in tested second hand condition good condition and in working order one item to include in our ads we are packing all these items into the 'BARGAIN PARCEL OF A with 50 and 75 baud xtals, data sheet and be worth Options: Floor standE 12.50 + VAT LIFETIME-. Thousands of components at -giveaway pricesi Guaranteed to large paper roll. ONLY E49.95. at least 3 times what you pay. Unbeatable valued Sold by weight KSR33 with 20ma loop interfaceE 125.00 + Dimensions 15" D x 5" H x 10" W Sound proof enclosureE25.00 + VAT 2.5kIs £4.25 + pp £1.25 5kIsE5.90+£1.80 CARR 16.00 Spare paper rolls £4.50 each Okls 110.25 + pp £2.25 20 kls 117.50 + £4.75 20,000 FEET OF ELECTRONIC AND COMPUTER GOODIES ENGLAND'S LARGEST SURPLUS STORE- SEEING IS BELIEVING!! D.C. POWER SUPPLY SPECIALS DUAL DISK DRIVE/ SEMICONDUCTOR Experimentors PSU Ex -GPO. All silicon electronics. Outputs give +5v @ 2 amps WINCHESTER CASES +12v @ 800 ma -12v @ 800 ma +24v @ 350 ma and 5v floating @ 50 ma. 'GRAB BAGS' Dim 160 x 120 x 350 mm. All outputs are fully regulated and short circuit proof. Very smart, fully enclosed case unit Mixed Semis amazing value contents Supplied in NEW or little used condition. Complete with circuit. full include transistors, digital. linear. I.C.'s trac Only £15.50 +2 £2.50 pp custom made to accept two or two diodes, bridge recs., etc. etc. All devices FARNELL 5 Volt 40 amps. Type number We -40A. This miniature switching PSU height 51/4" floppy disk drives guaranteed brand new full spec. with manu- measures only 160mm wide 175mm deep and 90mm high, yet delivers a massive winchesters such as the facturer's markings, fully guaranteed, 40 amps!! Fully regulated and smoothed with over voltage protecticn etc. 120 or RHODIME R0200 or TANDEM 50+12.00 100+15.15. with circuit at a fraction of 240 volts AC input. Supplied BRAND NEW and boxed series etc. An internal switched TTL 74 Series A gigantic purchase of an the current list price. Only £130.00 + £3.00 carr & ins. "across the board' range of 74 TTL series LAMBDA LMCC 5V BRAND NEW 240v AC input with 5 volts DC at 8 to 10 mode PSU supplies all the required I.C.'s enables us to offer 100+ mixed amps fully regulated output. Completely enclosed unit measures or ly 9" x 4" x 5" voltages to enable you to plug in "mostly TTL" grab bags at a price which two £29.99 your drives and go!! or three chips in the bag would nnormally LAMDA LMCC5V 110v AC input with 5 volts DC at 8 to 10 amps fully regulated Other features include mains filter, cost to buy Fully guaranteed all I.C,'s full output. Slightly smoke damaged, hence ONLY £10.95 spec 100+ 16.90 200+ E 11.30 300+ 119.50 PERIPHERAL SYSTEM SUPPLY. Runs almost any system. Fully cased unit internal cables with standard drive supplied in a brand new or little used condition. Outputs give 5v @ 11 amps "+" connectors, space for internal PCB. 15-17v C 8 amps'-" 15-17v @ 8 amps and "+" 24v @ 4 amps. All outputs are standard fan cut out and mounting, NORTH STAR HORIZON the 5 volt is fully regulated. Fan cooled. Supplied crowbar protected and output air Pro with 5" floppy tested with circuit. £55.00 + £8.50 carr. filter. Overall dimensions S100 system dual of POWER EX STOCK - 28cmWx30cmDx19cmH drives, software, manuals etc. 1000's other SUPPLIES £850.00 Call sales office for details CALL SALES OFFICE FOR DETAILS ONLY E55.00 +E6.00 CARR.

ULTRA COMPACT 300 BAUD PROFESSIONAL 6 FOOT LOGICAL KEYBOARD 19" RACK CABINETS Heavy duty unit in attractive satin alloy full travel keys in a LARGE 19" equipment cabinet. Totally case. 55 are laid out ACCOUSTIC MODEM COUPLER logical format of: - enclosed with locking front and rear A Major manufacturer's over production and 3 bulk buy doors. An internal sub tram 63" high is pre i special enables us to this BRAND drilled for standard 19" offer NEW . i , ®rlWID0 E i G TRANSDATA 307A ultra compact, BT APPROVED, equipment etc. Other tiillJ features include internal 300 baud full duplex accoustic modern at a fraction of A , i 12" cooling fan, two- iQ ...._ manufacturer's list price. The unit operates on the { j ton e blue and gley Di1©© Liuq standard CCITT V21 frequencies with RS232 finish with alloy trims. ">: Making a very useful keyboard, ideal for interface via 25 way 'D' skt. 4 Mounted on heavy persons unfamiliar with or confused by the Combine the adjustable cup sys-em, which duty castors, mains standard OWERTY layout. All keys generate i fits almost any phone with the benefit of panel etc. And at a the equivalent ASCII outputs and various "No jacks or phone cables" and a light liiI/O/ill: current cost from control codes shown in data. A 7 bit latched weight of only 1.2 Kg IMHOFS of over parallel TTL output with strobe enables and you have a truly £500 A snip at ONLY direct connection to any similar micro port portable modem!! Supplied complete with £125. Supplied in NEW etc. Many other features such as internal data, 90 day guarantee and -eady to use. -O- or little used condition. 240v to 5v PSU, MAINS ON/OFF switch. Carriage £22.00. Supplied In NEW or little used condition with Ext. Dim 72.5"h x data £49.95 + £3.00 pp ONLY £25.95 Post and packing £4.50 ONLY 23.5"w x 26'd 1000's of other EX STOCK items including POWER SUPPLIES, RACKS, RELAYS, TRANSFORMERS, TEST EQUIPMENT, CABLE, CONNECTORS, HARDWARE, MODEMS, TELEPHONES, VARIACS, VDU'S, PRINTERS. POWER SUPPLIES, OPTICS, KEYBOARDS etc. etc. Give us a call for your spare part 34 requirements. Stock changes almost daily.

won't forget, ALL TYPES and QUANTITIES of electronic surplus purchased for CASH e" CIRCLE 90 FOR FURTHER DETAILS.

ELECTRONICS & WIRELESS WORLD MARCH 1985 87

www.americanradiohistory.com The Archer -Single Ioacdmputer The SDS ARCHER - The Z80 based single board computer chosen by professionals and OEM users. FEATURES * High quality double sided plated through PCB * 4 Bytewide memory sockets - upto 64k * Power-fail and watchdog timer circuits * 4 Parallel ports with handshaking * Bus expansion connector * CMOS battery back-up * Counter -timer chip * 2 serial ports * 4 MHz. Z80A Telephone or write for full technical description and price information.

OPTIONS * SDS BASIC with autostart and "user program in ROM" facility * SDS DEBUG MONITOR: a powerful 8k byte development aid * On board 120/240 volt mains power supply * Attractive two tone instrument case herwood Da &'stern Ltd Sherwood House, The Avenue, Farnham Common, Slough SL2 3JX.TeI.02814-5067

CIRCLE 43 FOR FURTHER DETAILS.

COMPONENT PACKS (pantechnic) All Brand New exc ept where marked Price: £1 per pack Order 12 you get one extra FREE Please add £ 1 post if order under £20

35 - 4 battery model motors 1 - 5 13 amp ring main junction boxes operated 2 - 5 13 amp ring main spur boxes 36 - 2 air spaced 2 gang tuning condensons 3 - 25 13 amp fuses for ring mains 37 - 2 solid diaelectrlc 2 gang tuning condensors design manufacture and supply 4 - 5 surface mounting switches 38-10 compression trimmers 5 - 3 flush switches intermediate type 39 - Long 8 medium wave tuner kit 6 - 5 in flex line switches 40 - . 465 KC IF transformers 7 - 4 in Ilex line swithces with neons 4t - rocker switches 10a mains SPST 42 rocker 10a mains POWER AMPLIFIERS 8 - 2 80 watt brass cased elements - switches SPOT 10e 9 - 2 mains transformers with 6v la secondaries 43 - rocker switches SPOT 10 - 2 mains transformers with 12v (a secondaries 44 - rocker switches 10a SPOT HIGH POWER ASSEMBLIES 45 - 24 hour time switch mains operated 11 - 1 extension speaker cabinet for 6;' speaker 12 - 5 octal bases for relays or valves 46 - 6 hour clockwork time switch CONTROL CIRCUITRY 13 - 12 glass reed switches 47 - 2 lever switches 4 pole changeover up and 14 - 4 0CP 70 photo transistors ditto down 15 - 25 assorted gemanium transistors 0C45 etc 48 - 6v operated reed switch relays 16 - 4 tape heads, 2 record. 2 erase 49 - 1 neon valves - make good night lights 17 - 2 ultra sonic transmitters and 2 ditto receivers 50 - . 12v DC or 24v AC 4C0 relays for application in 18 - 2 15000 mid computer capacitors 51 - . 12v 2C 0 very sensitive relay 12v 4C 19 - 2 I. d.r. similar ORP 12 52 - . 0 relay 20 - 5 Jiff micro switches 53 - mains operated relays 3o 8a changeovers 21 - 2 mains interference suppressors (second hand) INDUSTRY 22 - 2 25 watt crossover units 54-1 rows o132 gold plated IC sockets (total 320 23 - 1 40 watt 3 way crossover unit sockets) PUBLIC ADDRESS 24 -250 screws and self tappers 55 - locking mechanism (with 2 keys) 56 - miniature Uniselector with circuit for electric 25 - 1 of each wafer switches - 6p 2 way; 4p 3 way; 2p 6 way; 1p 12 way jigsaw puzzle HI-FI 26 - 2 tape deck counters 57 - dolls house switches 58 telephone handsets 27 - 1 6 digit counter 12v - flat to make transformer 28 - 1 6 digit counter mains voltage 59 - solenoids - current 29 - 1 BOAC in flight stereo unit (s. h.) etc x 30 - 2 NICAD battery chargers 60 - ferrite rods 4' 5' - 16' dia available 61 - ferrite slab aerials LW 8 MW 31 - 1 key switch with key 32 - 2 humidity switches 62 - 200Q ear pieces 33 - 2 aersol cans of ICI Dry Lubricant 63 - Millard Thyristor trigger module ( 34 - 96 x 1 metre length colour-coded wires 64-1 assorted knobs spindles OFF THE SHELF 65 - dill thermostats CUSTOMISED C A D DESIGNED Most items available in quantity at good discounts. Access & Barclay cards welcome

tel. 01.361.8715 132 High Road telex 266 873 New Southgate N.B. ELECTRONIC SUPPLIES PANTEC G LONDON N11 1PG. 34 America Lane, Haywards Heath, Sussex RH16 3QU (24hr phone ordering 0444 454563) CIRCLE 47 FOR FURTHER DETAILS. CIRCLE 67 FOR FURTHER DETAILS. 88 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com It's OUT - NOW! it's the LATEST, it's the LARGEST and, it is the most COMPREHENSIVE CATALOGUE of ELECTRONIC COMPONENTS and SERVICING EQUIPMENT ever produced by for YOUR COPY of the HRS HRS for the Spring 1985 Catalogue Radio, TV and Video Service Department - call us on 021 - 771 2525

The stock range: aerial & audio equipment, batteries, sables, capacitors, cartridges & styli, cassette recorder spares & tapes (audio & video), cathode ray tubes, computer accessories, connectors, domestic appliance spares, eht rectifiers, fuses, hardware, hobby kits, holders, indicators, integrated circuits, loucspeakers, multimeters, oscilloscopes, power supplies, production aids. recorder spares, remote control units, resistors, security equipment, semiconductors, service aids, signal generators, soldering equipment, sound equipment, storage systems, switches, tools, transformers, tv spares, valves, wound components. HRS Electronics Limited Great Barr St., BIRMINGHAM B9 4BB Telephone: 021 - 771 2525 Telex 339992

CIRCLE 114) FOR FURTHER DETAILS.

12 CHANNEL GRAPHIC EQUALISER kit No 242 The mother board contains the Technical specification Fre- DC - 20 MHz Bandwidth. * Component Comparator. 2 slide potis (13,5 x 9cm) on quency resp. :10 Hz - 100 khz 2 mV/div Sensitivity. * 14 Trigger Functions. is the circuit Equalisation: 14 Hz, 28 Hz, 56 which plugged * X Mode. board (18 x 7,5cm). So the Hz, 100 Hz, 210 Hzz, 500 Hz, 2 EXTRA FORM. -Y only cables used are those for knz, 4 khz, 8 khz, 16 khz, 22 khz. pwr supply in/out signals!! Harmonic dist. :0,02% Max. Triple DC Output Source. Starting Price £297* Both pcboards are connected out signal: 7v rms Input res. with special connector/pins. :47 kout: 100R Powr supply: All polis with pins for pcboard ±15v DC, 100mA Master insertion. So, no cables, no volume with isolation. Ics confusion... used: (6x2) and one for input vol. output ampi. Signal vol- tage easily adopted for any combination.

Lengths ahead

3030 SINGLE TRACE DC -- 15 MHz Bandwidth. * Component Tester. 5 mV/div Sensitivity. 200 ns/div. Sweep Speed. Starting Price £179*

For the full form on both models, and our complete range, just give us a call. '(exc. VAT) At\ C & A ELECTRONIC O.E. PO Box 25070 Athens 10026 Crotech instruments Limited GREECE TeI:5242867. TIx:210798 CAGR 2 Stephenson Road, St. Ives, Huntingdon, Cambs. PE17 4WJ Telephone: (0480) 301818 32/30/10/4/1 CIRCLE 16 FOR FURTHER DETAILS. CIRCLE 91 FOR FURTHER DETAILS. Si) ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com INVERTERS TRANSFORMERS EX -STOCK 12/24 V DC -240V AC MAINS ISOLATORS 50/25V or 25-0-25V 30/15V or 15-0-15V 100W ...... £05.15 Pri/See 120Vx2 2x25V Tap Secs Volts 2x15V Tap Secs. Volts 250W 1172.70 Tap Secs) available 5, 7, 8,10,13, available 3, 4, 5, 6, 8, 9, 500W £196.19 11S44 159 559 (60-1000VA 44117 OP B0680 Pip 81615 321 as 2X.2369 VOLTAGE 2090494 LM747 T1661 11, 369 10,12,15,18,20,24,25.27 1000W £396.72 4419 Sp 80681 Yp 81758 41p 2N.2484 2Á4 REGULATORS Wp 149749 VA Price P&P 15, 17, 20, 25, 30, 33, 40, 44132 111 80682 459 81869 229 7150871 450 24.2646 Yp 2804110 2109 1611458 30 or 15-0-15V 7805 359 20 5.82 1.60 20-0-20 or 25-0-25V 2000W £779.90 40107 tip 80%32 1099 81070 229 11S90 159 24.2901 209 Z80BP10p1M 481400 7812 359 30V 15V Price P&P AC126 17p 80465 000 8í872 230 TIS91 110 2X.2905 200 Z040í0 íM1 M-515131 60 9.49 1.80 50V 25V Price P&P 4000W £1160.00 71593 208 110 7815 359 A0127 159 00592 100, 131960 Np 2N.2906 Z8080í0 IMP 1009 1 1.40 0.5A 7818 356 100 11.08 2.00 0.5 4.13 4C126 15p 89180 lOp 81963 411 2X.2907 18p 2409510 MIp M-51515BL 7624 1 2 4.72 1.40 CONSTANT VOLTAGE 401286 239 81181 110 89964 319 V%t 010 ap 2X.2926 1,9 358 280001001 2719 200 15.66 2.25 1 2 5.03 1.50 7º05 359 Á0141K 309 81103 209 8X966 12p VN_10KM 100 29.3019 210 ,Opp M-51516 2110 1.84 2 A 4 6.99 1.60 TRANSFORMERSI% 7912 109 250 16.97 2.64 2 4 8.69 40142K 3n9 85104 299 61940 259 VN.10KM 606 2X.3053 189 Z80Á51012P, N-515170 mains 7915 449 311p 1.90 3 M 6 8.10 1.85 Spike-Ireestable 401538 230 81 105 219 1391St 219 84 464í 559 2X.3051 359 71 350 23.47 2.70 3 A 6 10.36 109 *0176 119 81191 Sp 81062 210 VII 664F 1009 24.3055 359 1918 28060491 943112 1099 4 8 14.10 2.12 4 P 8 9.67 1.90 250VA £172.40 7921 SUP 500 2913 2.95 M 401760 219 81195 5p 89479 269 9X.8041 115p 79 3055H 50p me M83730 2609 £196.69 78105 280 6 P 12 18.01 2.20 5 S 10 11.95 2.00 500VA 40167 159 BF196 Op BFR90 529 06.8989 114 28 3440 54 U83756 2X0 750 4128 3.70 80429 1209 78012 289 4901327 710 6 £338.40 901878 211 81197 7p 81491 111 24 3442 85p LEO 1000 53.00 4.00 8 S 16 24.52 2.70 12 13.52 2.00 1KVA 811500 1108 9p 78115 180 4655 ZIp 90184 170 89198 Ip 81429 20, 24 3702 8 £594.50 009 78118 28p LEO 3mm 690 419 10 20 3023 3.00 16 .18.10 2.26 2KVA 601888 230 99199 Op 81%84 Zap 80526 2N 3703 9p NE556 1500 68.37 4.70 78124 28p 33 80118 409 81200 Up 81605 215 80801 959 2N 3701 90 040560 119 3.20 10 20 20.88 2.26 3KVA £840.00 79105 48p LEO 37nm EFL 2000 82.27 5.10 12 24 36.18 40119 419 81240 99487 15p 80806 114 26.3705 9p 545570 1109 lIp 79L 120 10p 12 24 2320 2.50 4KVA £1266.00 80142 Op 8F241 111 8F488 150 8U807 950 26 3780 9p 06760036 3000 115.35 OA 2, 3107 791.15 480 1E04117 GRN 144 60/30V or 30-0-30V 15 £1531.00 90149 Up 86255 129 89789 6E11 9p 6000 203.65 OA 30 26.60 300 5KVA 23p 1.143098 100p LIP 66760235 90161 229 B6256 lip 89717 359 01060 28.3708 99 Pri 2x120V. 2x30V Tap 20 11743.00 0483178 220p LED58m RED 240V 40 35.64 4.83 6KVA 40162 np BF257 lop 81V18 40p 2N.3771 85p 144 115 or sec only. LM3177 180p 5/ Secs. Volts available 41121 25p Elf 2513 lSp 81041 211 MJ2500 100P 29.3772 94 06760234 AUTOS 7.5KVA £2073.00 293239 4209 LED 5mm YEl 1100 6, 8, 10, 12, 16, 18, 40125 25p 89259 lip B1150 lIp MJ2501 1100 28.3773 104 400/440 to 200/240V CT LM723 32p 105, 115, 220, 230, 240V 10 KVA £3347.00 40126 250 89262 26p 81151 180 0122955 659 263019 op le 06760339 7811090 5709 LED 588 GXN VA Price P&P 20, 24, 30, 36, 40, 48, 60, 46127 269 89263 259 91152 180 MJ3000 115p 29.3666 689 For step-up Sr down AVOs & MEGGERs 1840581 5209 180 ÁF139 220 81270 110 8/156 254 0J3001 1161 24.3903 lip 5461106 'lap 60 9.50 1.80 24-0-24 or 30-0-30V. £138.70 780010 1600 VA Price P&P 8Mk6(latest) 41239 229 81273 159 89157 260 4906296 309 24 3904 111 0476115 10p 790310 2159 100 11.08 2.00 Price P&P £68.40 91112 709 81311 itp 81164 259 90304 308 24 3905 lip 728000 52p 60V 30V 80 4.84 1.40 DA211 LCD 6709 40113 Np 269 59090 459 00340 259 29 3906 119 791109C TA 7120 559 200 15.68 2.25 81324 0.5 1 4.70 1.50 150 7.01 1.60 042000 LCD £72.80 00350 004 TA -7137P 830 85215 1000 81336 209 82148 150 2x4031 25p 18.97 2.40 250 1 1.50 AS217 1000 81337 Op 5L149 159 841520 309 24 4036 259 74-7146P 2 7.15 350 11.84 2.00 DA117 AUTO £157.00 84JE29558 904 ÁU110 110p 81338 21p 8N200 149 2N 4037 25p OPIO alp 350 23.47 2.70 2 4 9.20 1.90 Gen £116.40 7A -193P 4119 500 13.30 2.24 Megger 4Y102 2041 81367 13p 89101 Up 26 1058 139 ELECTRONICS 500 29.23 2.95 A 1009 04103 0028 1000 26.4413 760 74-7200 248p9 3 6 13.31 2.00 1000 24.14 2.80 Batt Megger £85.50 41106 81371 17 370 2X.6111 Y 86414 85X20 lop 0029 lop 2X.1444 760 TA -7201 1111 1000 52.98 4.00 84145 109 119 1009 4 8 15.15 2.20 1500 0035 1004 VALVES 00179 TA -7203 28.17 3.20 Transistor Tester 8 8148 101 13 15p 28 5061 21p 1X0 TT169 Bí120 l0%2669 0X112 651 2000 8227 5.00 0036 1209 24.5294 309 TA -7204 1148 5 10 19.16 2.20 2000 42.14 4.00 04154 69 131121 lq N%29 lIp 08.96 609 0R160 1119 S £61.30 129 Bí106 Mp 0015 SOP 2X.5296 0p 58p 18-7205 Np 3000 115.37 OA IA157 «422 219 0166 7X192 11610 6 12 21.66 2.65 3000 71.64 4.80 P&P £2 VAT 155, 0071 569 26 5299 34404 TA -7110 205088101 139 13E423 155 Bí109 479 6000 228.75 OA 30.72 3.00 09103 16p 89440 151 01116 9800192809 0072 50P 2N.6107 489 3186 50p 16-72204P 8 16 5000 108.30 OA 00200 1009 74 6109 489 1201 081058 110 0X451 lip 01119 UN 0887 50p 24/12V or 12-0-12V 10 20 35.76 3.30 CASED AUTOSI240V cable WW MODEM PROJECT 802058 24p 81455 180 07120 lily 01802 150 14.7310 920088 1049 1000 12 24 41.22 3.50 80107 10 99158 111 801006 1109 36. 128 559 E48000 Sop 2 x 12V Secs. Pri. 240V UP 115V USA skt outlets Transformers T1, T2 R20100 100p 270p BC108 Ip 89459 lIp 80104 1559 39. 743 659 E891 up pm..., 18-7609 74450 lip 12V 24V Price P&P VA Price P&P £6.90, pain inc VAT, P&P 00109 1p 81461 009 90105 Up E0F80 45p 94X01114 MINIATURES 1804443 769 480 .15 2.41 .90 10125 lIp 81462 129 60110 1109 5131e9 500 1305 series 70X1200 0.3A 20 80111 1460 1464444 709 784395 600 METAL OXIDE ''/.W 80218 11p 81469 341 E0082 404 1 5 Amp TIP29 15p CMOs 3.19 1.20 Sec V Pri P&P 80 9.3521 1.50 BC140 119 81470 219 60124 Np E0063 139 784396 Yp 5 RESISTORS 11/100 111294 220 784520 1000 2 1 4.25 1.20 / 80141 148 86471 289 80126 lIp 90084 40p 3-0-3 .2A 3.11 .90 150 12.10 1.90 784530 104 90142 IN, 81479 309 0U204 159 E0085 409 2 12 20, 33, 47, 75, 390, 430, 11,290 250 918853 4 4.91 1.60 6x2 lAx2 3.45 1.20 250 14.73 2.00 90143 199 81493 10p 8U205 70p 60981 490 TBA510 1009 71P30 258 3 51012 560, 1k, 161, 1k3, 80147 Op 89494 lop 8U212 75p 48119 9p 504131 521 188580 1109 6 7.69 1.60 9-0-9 .1 2.59 .90 500 24.14 2.20 71P300 308 188750 1489 00148 61 61595 169 902084 809 01200 LOP 50180 574 90'3 4 1k6, 1k8, 2k, 3k, 3k9, 15k, 24p LINEAR 8 A 8.98 1.60 9x2 .33x2 2.41 .90 1000 3374 280 00149 ap 89596 169 0712080 1000 715314 80103 320 60082 54 1134000 350 16k, 24k, 27k, 715310 309 716-2145 2099 11348103 800 10 5 9.82 1.80 39k, 56k, 80157 Bp 81597 lip BU325 55p BY126 60 ECL84 579 M 8,9x2 5x2 3.36 1.20 2000 60 47 450 71532 240 AN-240 150p 188020 ßp 82k 100k, 110k, 120k, BC159 69 89615 309 80326 Np 81127 0p EC105 579 12 p 6 10.89 1.90 427 1.40 715328 240 AN-360 1200 708920 1000 8,9x2 14x2 3000 86.80 5.70 130182 M 81758 up 80406 Np 9E133 Bp E0155 190 130k, 150k, 200k, 220k, 115320 289 -7110 1489 784950 1049 16 S 8 12.97 2.12 .90 00102L M 01869 np 804060 Np BY164 444 E980 310 AN 15x2 .24x2 2.41 EDUCATIONAL METERS 11033 609 1600 76A990 1009 300k. P&P 20p. BC183 Op 89870 tip 4407 759 80176 859 0180 Up AN -7114 20 10 17.46 2.44 12-0-12 .05 3.11 .90 270k, 71P34 SOP 1100 Front finger screw 801831 60 89872 039 1301070 159 130179 354 9189 430. 404-7215 708270 489 711418 22p 149 704300 2014 30 15 21.69 2.64 3.39 1.20 BRIDGE RECTIFIERS 80164 69 81960 Sap 1513412 Np 61182 319 9X163 450 444-7120 20x2 .3x2 terminals 78x98mm í3P410 250 4X3-1270 704940 1009 801611 6p 89963 Up 804080 809 60184 319 EF184 53E134 44.45 229 60 30 OA 20x2 .15x2 1.50 .50 1A 400V .32 BC212 Ip 89964 34 80409 Np T14424 8X107 329 1900 0000 7041170 1090 0-10A DC - £3.98 71542C 250 60p 83 41 4.50 002121 Op 89966 Up 901426 1250 81196 008 0136 600 813.1350 7041412 5120 20,12,0 0_30v DC 2A 200V .45 409 £3.98}'p&P 80213 Ip 89440 25p 80500 1119 11547 81206 110 XLB/ 50p 30OP 70X2002 Mp 71545 96/48V. Pri 2 x 120V 12,20 .9 4.13 1.30 354 100V £2.60 002131 4 89451 269 90526 Np UP 91207 lip 9195 508 03-8910 1042003 154 íI590 7082020 1Yp PLEASE AN15%VAT 16 80214 69 81662 21p 911001 Np 6Op 80208 189 EL500 009 3000 Seca 2 x 36/48V 15,20-2 14x 2 5.60 1.60 52 100V 13.20 1200 AFTER 802141 Ip 89P79 25p 60806 1219 TIP51 139210 209 61504 1000. 813-8913 1082030 100 ALL ITEM; PIP 1206 60,72,84,96,36-0-36 15,27x2.5x2 4.83 1.40 12..54 500V £3.40 80237 7p 81P90 629 50607 Np 17P52 BY223 729 0195 34 400p 0082522 NP TIP53 1200 4E5-3600 80238 4 89X91 99p 131225 1219 E107 319 0042530 1Np or 48-0-48V 15,27x214x2 7.30 1.60 71P54 1489 1189 80300 180 139429 20p 01060 24 61226 18p EY88 429 0709 1062532 111105 050 80382 109 016134 206 14712500 100 6E226 329 1235 459 CA270 400 1062540 1809 72/96 36/4V Price p&p 0-7.5-15V 0-5A2.53.90 50P ARRIE ELECTRONICS LTD 80302 lip 89485 20p 48122501 110p 715106 071216 208 EZ80 50p 083046 OOP T062560 lap 4A 6.901.40 71P101 088 083048 1106 1862593 0.5A 1 5.37 1.20 0-7.5-15V BC303 l48 136407 159 7412955 550 9y099 209 E781 559 100,80327 111110 74 Ip 131488 15p 913000 1159 80476 109 G234 1489 083060 2006 1042500 lap 2 A 4 14.69 2.20 0-27V 14 1.50 .50 it 211, Stratford Workshops ap 709 8C528 Op 09989 ND 843001 1150 115111 80410 159 PC97 100p 043060E UP0-5554 Np 71P112 400 3 M 6 17.79 2.40 9-0-9V 1A 2.20.60 BC337 1p 89117 34 049298 309 99%55/350 P0048 429 CA3066 560 050-5564 Np Mord Road, London E15 2SP 115115 450 1559 3.20 80338 Ip BFY18 489 9129304 309 348 PCF80 50p 083089E UPC-57502 5 P 10 3223 3.20 100V/45210W 11P116 450 99955/600 1900 80557 N 89841 280 MJE340 250 P09200 134 CUOMO 10W .90 el: 01-555 0228 (3 lines) 509 3Mp 010-5774 809 6 12 40.36 3.50 60132 1509 81X51 119 006520 UM T11111 311 p0965 t ppp 5 466 083130E UPC WW 6 130034 1809 B9Y52 110 MJE520 308 71P1204 BY%55/MO PC6802 15p Np -59242 8 16 44.03 3.75 14 DAY WIND SERVICE 411 807142 1284 81152 16p 48125215580 NO TIP122 329 PC406 loop 0431481Mp Np 470 BCY59 28p 89157 259 710122 BY%70/300 p018 1510 CA3269E 311 Ú0C-100180 711126 170 80070 109 89164 26p 0028 1Xp 219 019 CA30409 re 9209 75 FOR FURTHER DETAILS. 00171 109 81190 469 0039 004 715126 569 89470/500 P0/84 04 083210E Np UP0-10254 CIRCLE T14141 00172 lip 81190 469 0036 10042 569 Up PCL85 55p XA-11NW 2309 7/P142 80112 169 61.949 450 00365 1X9 MP 81X80180 poros 559 1189 Ú0C-10260 65P 60125 Sep BL140 161 0071 506 í1P142 311 PCL8fi 55p HA-1301 1519 604 7/P115 654 080-10284 801211 110 8110 439 0071 509 8Y071300 P11200 559 X4-73NW 71P146 999 00121 1110 01101 439 0072 609 009 PLL200 959 1111 2Np 71P295 I41p 80131 Up 80420 15p 00200 1300 0890 49 5142 809 99-1339 2609 UPC -10311 TIP2955 114 80131 Np 85X20 169 0ÁM 4p 5183 356 69-1342 1]4 1480 TIP3055 459 'UPC 138132 NI 85%29 tap 920108 1489 0021 11 PLB3 326 H-41366 /Tap -103280 71513 139 BY N -Á1366W1 iM SALE AUCTION 80136 219 85X06 lip 920108 IMp 00202 71 PLB4 508 05C-1155 80136 219 67709 119 71043 159 04974 11 PL95 1489 1600 71541 15p HA -13óB 1200 80138 210 01119 lap 1X04443 14p N 901 41 11500 114 80139 219 81116 559 769 11581 454 N 4002 N PL501 70p HA-I377 140p UPC -í156N TIS60X 154 44-1397 2409 HYp DAY 1 12 March, 85 80140 40p 87120 1489 TIP29 22p 8.4003 M 61509 1500 - X8-1397 234 0P0-11814 80140 21p 07100 1190 131294 Z2D T1591 18p N 4003 N 61809 1709 60144 Mp 8Ú100A 1180 71591 181 8 4004 N ,180 up 44-1391 0409 1159 90150 350 0010 lap 7/530 Np 71593 209 X.1005 y pm lap 441398 2489 0P0-118248 Tektronix 491 19-1351 Np Electronic Test Equipment including: 80157 319 00105 000 71P30 359 4006 49 118008 1809 1500 00166 319 00112 114 711800 24p 061108 608 41008 N 04-1355 1400 UPC -1113526 2609 00175 300 81111 1159 711314 249 VN.4641 808 6.5440 2p LA -3301 1409 7313 Oscilloscopes, 1209 -13500 Spectrum Analysers, 7704A, 00175 Mp 60124 1100 TIP320 240 VN6681 000 4.5402 Op LA -3301 UPC 1509 10179 320 60121 Np 71P32 219 VN 8861 1150 4 5402 10p LA -3361 115p 10179 ßp 00104 lop 116320 210 VN.8691 1109 4.5403 lIp LA 3361 1159 HP.Logic and Network Analysers, 8640 and other Signal 80181 Yp BÚ205 7óp 716330 219 1VN18/071 1109 0.5404 lip LA -40301 2Np 80183 Alp 00208 75p 11134 60p 178208 110 0.5401 lop LA -1032 1409 1óp 11134 MD Zí4101 111 X.5/05 109 LA -1032 1459 Generators, Oscilloscopes. Telequipment Osciloscopes. 130947 bop OÚ208 COMPUTER 108 O0í87 319 832089 000 11P410 229 174109 120 0.5406 130 LA -4050 1309 176202 271 2114 19-4051 lap 80201 330 802084 300 11P420 250 95407 130 200 Marconi Equipment. Plotters, Power Meters, etc, etc. MO 802080 1100 13P428 020 178300 13p 0.5408 131 2516 2000 14-4100 1209 80202 JAPANESE 55p 7420 250 170301 lip 2532 370p LA -4101 1104 80203 429 4325 TRANSISTORS 80214 Yp 80326 Up 71547 480 278303 148 2716 30p IA -410258 404 109 80222 31p BÚ406 Np 71P40 a0 714303 24 2732 258324 55p Equipment including: Qty. new 14" Colour 4159 Computer 130225 310 804060 Np TIP50 508 11X304 119 2764 LA -4112 NS 25850] Up 60232 310 90407 75p 7IP51 1289 214320 210 21128 1100 L9-4120 2119p 25875/ NO 80234 320 604070 100 71152 lap 274326 219 4116 750 LA -4140 709 250,499 011 Video Monitors, Texas and Motorola Computer Systems, 3500 19-/201 120p 00235 219 80100 Np 7Ip53 120oo0 774500 139 ZEXERS 4164 2501060 100 1809 80236 329 601090 Np 11554 1100 174501 139 6116 4009 10.4120 2501061 210p 800MV 1.074400 1489 Drives, Altos Computer systems, Emulators, 80137 24 80409 804 IIP105 654 111502 lap 626115 2009 2501096 219 40MB Disk 7 a 80254 240 89367 13p 714106 650 218503 tip 6502 3206 LA -4120 1484 2501161 1199 297 to 390 BP 14-4422 1300 80144 550 89311 17p 21P107 65p 1T%504 25p 6802 1409 2501172 109 Printers and 826919RS 19-4430 1109 5 Portable Andromeda Computer Systems, 80245 609 09421 lip TIMID 470 114550 240 6809 500p 2501306 Np 81X61 Range 80433 219 Bí420 16p 711111 Sop 6821 1500 04-4460 1709 2501307 IMP 207 to 39V 3209 80134 380 131421 14 71P11 400 29.696 209 6840 LA -141 184 2001870 1219 I.C's etc. 6850 1209 80435 31p 61422 2SP 71P1165 450 2N.697 rep 121 1300 1_4-5112 2501969 1301 80437 219 81423 15p 71P116 /SP 24.698 IIp 0004 4800 1.171301 260 2502028 75p 489 0085 530p 149311 359 500 lots. 80138 311p 81440 169 7P117 500 2° 699 2002029 1209 Components and General Surplus. In all some 80439 IN 86457 17p 71/P120 430 26 7064 22p 0155 4709 148311 350 2502070 1208 45p 80440 Yp 81455 lop í3P121 460 2N.708 129 0156 3800 134335 00441 Up 81458 199 TIP122 47p 2N 911 280 8250 1800 10339 409 2N.9 366 8251 4700 103 60p 80442 Op 81459 1/9 TIP125 470 LOW PROFILE 5800 80533 64Bí461 up 11P126 569 26.93030 109 500.675 8253 14838080 100p DAY 2 13 March, 85 80534 AN 81462 84 111121 569 1°.1131 204 8255 600p 1171381 1500 - 60535 31P 51469 309 11514/ 909 24.1132 28p 8 p77 6p 8288 100p LM382 1000 80536 300 81470 9p 111142 900 24.1813 249 74 P,n Ip 413.1015 149381 SNP 90537 400 09471 250 115145 55p 2X.1711 240 169ín 90 2904 191109 Olt Fork Lift Trucks, Bearings, Hardware, Cable and Wire, 18611 300 138539 Up B1479 309 71P146 900 29.0102 509 120 485-3600 80675 400 88493 110 111111 1489 2N.2160 3006 20 6,1 180 5700 10723 40p OIL 00876 Up 81494 169 1182955 44 2N.2218Á 240 22 8,1 109 5/0256402 L11741 Motors, Howden Universal Tension Tester, Fry's Flow 00677 319 81595 16p 1153054 4 2x.2219 24p 2414n 110 1ó4p lip 0678 481 85566 160 7143055 42p 2N.2221 239 20 011 N, 2800010 8610 148741 MET believed unused, Optical Test Stations, 80679 YO 81597 109 71583 484 24.2222 250 40011 809 2800050 5480 48p Soldering Line, Gilt PCBs and General surplus, in all some 450 lots. PLEASE PHONE US FOR TYPES NOT LISTED HERE AS WE ARE HOLDING 3000 ITEMS AND QUOTATIONS ARE GIVEN FOR LARGE QUANTITIES. Suitable entries still accepted for both days. Please add 50p P&P and VAT at 15%. Govt, Colleges, etc. Orders accepted. Closing date for entries 28 February, 85. Please allow 7 days for delivery. All brand-new Components. All values are new and boxed. Catalogues available from the Auctioneers. Price £1.50 at: LTD INDUSTRIAL AUCTIONS LIMITED GRANDATA Bromyard Road Industrial Estate, 9 & 12 THE BROADWAY, PRESTON ROAD, WEMBLEY, MIDDLESEX, ENGLAND Ledbury, Herefordshire. Telephone: 01-904 2093 & 904-1115/6 Telephone Ledbury 5456 Telex No: 932 885 (Sunmit) CIRCLE 21 FOR FURTHER DETAILS. 90 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com DGS001 2 -MOTOR, HIGH QUALITY REPLACEMENT NSLEY-HOOD SOLENOID CONTROLLED 0 CASSETTE DRIVE. CASSETTE HEADS 300 SERIES AMPLIFIERS Fully solenoid controlled cassette mechanism suitab:e for Hi-Fi or a digital use. With a logic control board the deck can be operated by lightweight touch / contrors or output from a micro. Ideal for Do your tapes lack treble? A worn head could be the problem. applications under Fitting one of our replacement heads could restore performance automatic control such to better than newt Standard mountings make fitting easy and as telephone answering our TC1 Test Cassette helps you set the azimuth spot-on. We are machines, data loggers, the actual importers which means you get the benefit of lower automatic background music systems, remote control recorders prices for prime parts. Compere us with other suppliers end seal and microcomputer program The following is a list of our most popular heads, all are suitable 35 Watt Complete Kit. MosFet 0/P £79.50 and data storage. Two motors and three solenoids control all functions including for use on Dolby machines end ere ex -stock. 45 Watt Complete Kit. MosFet 0/P £83.50 search in fast forward and rewind. HC20 Permalloy Stereo Head. This is the standard head fitted as Reprints of Original Articles from 'Hi -FI News' £1 no VAT. Standard fittings include reed switch for auto off, 3 digit counter, original equipment on most decks fá.11 stereo R/P and erase Head. HM90 High Bete Permalloy Head. A hard-wearing, higher per- Overall size 176mm x 130mm X 75mm. formance head with metal capability £8.06 LINSLEY-HOOD 100 -WATT MOSFET DGS001 Cassette Mechanism. C37.25 Quantity prices on HS16 Sendust Alloy Super Head. the best head we can find. POWER AMPLIFIER request. Longer life than Permalloy, higher output than Ferrite, fantastic INF140. Full technical specification and drawings C1. frequency response £9.91 The very latest amplifier design, published in 'Wireless World' by H0551 4 -Track Head for auto -reverse or quadrophonic use, Full the renowned John Linsley -Hood. This may now be taken as AM VARICAP DIODE BARGAIN Super wide range the SMV2012 specification record and playback head £9.73 standard by which the rest are judged! Our kit, approved by varicap diodes in matched sets to eliminate tracking errOrsl the designer, has massese heat sinks and power supply Please consult our list for technical data on these and other and Matched pair only 25p. Matched 4 only 60p. Special includes all components needed to build. Case size 412mm Purpose Heads. wide, 254mm deep and 145mm high. Automatic switched SET OF 4 COILS to use with above to make long, medium and MA481 Latest version Double Mono (2/2) Record/Play heed. speaker protection is included as standard. Cost of all parts is short wave AM tuner. Normally 30p each. OUR PRICE FOR THE Replaces R484 £8.90 over £120. Our complete stereo kg price £105.50. SET ONLY 55p SM166 Standard Mounting 2/2 Erase head. Compatible with INF10 and Application circuit using coils matched pair of above or H0551 4 Track head. £ 5.90 SMV2012 varicaps. 35p LINSLEY-HOOD CASSETTE RECORDER H524 Standard Erase Head. Semi double gap, high 168A IF Transformer 30p effi- CIRCUITS CFU455F2 IF Filter 50p ciency £1.50 Complete record and replay circuits for very high quality low Suitable PC Board £1.50 H561 Metal Tape Erase Head. Full double gap £4.90 noise stereo cassette recorder. Circuits are optimised for our Push Button PC Mounting Wavechange Switch £1.60 HS16 Head. Super Quality Sendust Alloy Switched bias and COMPLETE STEREO TUNER MODULE HART TRIPLE -PURPOSE TEST equalisation to cater for chrome and feric tapes. Very easy to Three band LW/MW/FM Stereo Tuner fully assembled on PCB assemble on plug-in PCBs. Complete with full instructions, 165 x 85mm. Supplied with Ferrite rod aerial and band switch CASSETTE TC1 Complete Stereo Record/Play Kit £25.26 fully wired. Facility provided to drive tuning meter and stereo One inexpensive test cassette enables you to set up VU level, VU Meters to suit E2.30 each LED. Only needs 12v DC supply. FM sensitivity. 2.5uV. Prise head azimuth and tape speed. Invaluable when fining new Reprints of original Articles 75p. No VAT. only £7.99 Inc. VAT and post. heads. Only £4.66 plus VAT and 50p postage. STEREO 10W POWER AMPLIFIER MODULE Tape Head Demagnetiser. Handy size mains operated unit STUART TAPE RECORDER CIRCUITS Ready built and tested music centre power amplifier module prevents build up of residual head magnetisation causing noise on playback E4.54. Complete Studio quality record/Play electronics to complete and ready to use. Mains input 220/240v with power to Pole Type for inaccessible heads 64.85 bring that old valve machine back to life. Full details spare for tune and tape deck. Size 190 x 110 x 85mm. ONLY Curved in our REPRINT £1.30 (No VAT). £8.90 plus Vat and Post. Send for your free copy of our LISTS. Overseas please send 2 AUTOMATIC 10 -CASSETTE AUTO PLAYERS IRCs to cover surface Post or 5 IRCs for Airmail. PW WINTON STEREO AMP Suitable for background music systems. Lenco type PACIO Please add pad cost of post, packing and insurance as follows: HiFi Kit giving 50 Watts per plays each casette forward and backwards before changing to Super Mosfet Amplifier INLAND OVERSEAS the neat. Any cassette may be rejected at the touch of a button. channel at .014% distortion, housed in attractive Orders up to E10 - 50p Please send sufficient to cover Full Kit is normally £109. Mains powered, Wood finish case with perspex top cover, play E1 wood veneered cabinet. Orders C10 to E49 - Surface or Air Post as of througn any high quality stereo amplifier system. Orinally over Orders OWN E50 - 1.50 SPECIAL OFFER, NOW ONLY £89. Reprint required. descriptive articles 85p (No VAT) £500 each! Our price for ex -demonstration models only £230. One only Brand New £310.

Personal callers are always very welcome but 24hr SALES LINE ALL PRICES EXCLUDE VAT it please note that we are closed all day Saturday (0691) 652894 I UNLESS STATED Multi-Function Calibrator 9822

50 ppm ACCURACY (20 ppm optional) IEEE -488 INTERFACE SELF -TEST FEATURE AUTOCAL

0-1000V AC/DC VOLTAGE 5 ppm RESOLUTION 0-10 AMPS AC/DC CURRENT 6 AC WAVEFORMS 10 ohm -10M ohm RESISTANCE 25% OVER RANGE ON DC BI -POLAR OUTPUT ZERO OFFSET MODE

TIME ELECTRONICS Botany Ind. Est., Tonbridge, Kent, England DIRECT SALES T (0732) 355993 Telex: 95481

CIRCLE 122 FOR FURTHER DETAILS. ELECTRONICS & WIRELESS WORLD MARCH 1985 91

www.americanradiohistory.com Appointments

DISPLAYED APPOINTMENTS VACANT: £ 19 per single col. centimetre (min. 3cm). Advertisements LINE advertisements (run on): £4.00 per line, minimum £25 (prepayable). accepted up to 12 BOX NUMBERS: £5 extra. (Replies should be addressed to the Box Number in the noon Tuesday 5 advertisement, c/o Quadrant House, The Quadrant, Sutton, Surrey SM2 4AS). March for April PHONE: IAN FAUX, 01 661 3033 (DIRECT LINE) Issue 1 Cheques and Postal Orders payable to BUSINESSPRESSINTERNATIONAL LTD. and crossed.

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£7,000-£30,000 + CAR e Where * does your interest lie: Graphics; CAD; Robotics; Simulation; Image and Signal Processing; Medical; Automation; Avionics; Acoustics; Weapons; Comms; Radar; Opto and Laser? * Experienced in: VLSI; Microprocessor Hardware or Software: Digital and Analogue circuitry; RF and Microwave techniques'? * There are hundreds of opportunities in: Design: Test: Sales and Service for Engineers and Managers * For free professional guidance: Call: 0638 742244 (till 8pm most evenings) or write (no stamp needed) to ELECTRONIC COMPUTER AND MANAGEMENT APPOINTMENTS LIMITED FREEPOST, The Maltings, Burwell, Cambridge. CB5 8BR.

At H.M. Government Communications Centre we're using the very latest ideas in electronics technology to design and develop sophisticated communications systems and installations for special Government needs at home and overseas. Electronics With full technical support facilities on hand, it's an environment where you can see your ideas progress from initial concepts through prototype construction, tests and evaluation, to the pre-production phase, with a chance to Engineers influence every stage. Working conditions are pleasant, the surroundings are attractive, and the career prospects are excellent. Ideally we're looking for men and women who have studied electronics to degree level or equivalent and have £10,039 had some experience of design, whether obtained at work or through hobby activities. Appointments will be made as Higher Scientific Officer (£7435-£10,039) or Scientific Officer (£5909-£8153) according to qualifications and experience. Communications For further details please write to the address given below. As our careful selection process takes some time, it would be particularly helpful if you could detail your Design in qualifications, your personal fields of interest and practical experience, and describe the type of working environment most suited to your career plans. High Tech Country The Recruitment Officer, HMGCC, Hanslope Park, Buckinghamshire MK19 7BH. (2448)

92 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com UNIVERSITY OF LIVERPOOL INSTITUTE MEDICAL AND Senior Development Engineer OF DENTAL BIO -ENGINEERING Granada houses and manages one of a number of small Technical Development Laboratories TECHNICIAN whose work is funded and directed jointly by all the Independent Television Companies. The GRADE 3 (ELECTRONICS) function of these laboratories is to investigate new techniques, theories, and equipment in relation to broadcasting in its widest To assist with circuit design, sense. construction and maintenance of A vacancy exists for a Senior Development Engineer in the above laboratory. Suitable electronic control equipment in a applicants require basic knowledge of colour television principles and some knowledge of any medical research laboratory. of the basic technologies encompassed within the general framework of broadcasting. These Candidates must possess O.N.C., include colorimetry, optics, magnetic recording and digital and analogue circuit design. Work Intermediate T.E.C., or is undertaken in a purpose-built laboratory and applicants will be responsible for complete appropriate equivalent as projects from specification to final documentation. minimum qualification plus three This is a specialised appointment providing freedom of expression for men or women of ability. years experience which should Commencing salary is £12330, with the usual large company benefits including re -location include general workshop skills. assistance, contributory pension scheme and free Life Assurance. This post is available for Iwo Written applications including a full cv together with all other relevant information should be years. sent by 1st March to Salary within range £5399 - £6325 per annum. Bob Connell, Ref: A26, Application forms may be Granada Television Ltd., Quay Street, obtained from the Registrar, the Manchester M60 9EA. University, P.O. Box 147, Liverpool, L69 3BX. Quote Ref: RV/938/EWW 24s GRANADA TELEVISION An equal opportunity employer (2479) J SALES ENGINEER A small division of a large electronics Group involved in the manufacture and marketing of R.F. Test Equipment requires an enthusiastic self - motivated Sales Engineer. Existing knowledge/experience of R.F. Test Equipment and advantage. Potential involvement in U.K. and overseas markets. Analogue Write to:Radio Telephony Test Systems Enterprise House Central Way Engineers North Feltham Trading Estate Feltham Middlesex TW14 ORT Required for challenging work in or telephone Mr G Varrall Mr R Belcher 01-844 1811 State of the Art Technology (2500) AN OPPORTUNITY TO DEVELOP YOUR SKILLS TELECO If you have high frequency circuit design experi- ence relevant to one of the areas listed below, we would be most interested to hear from you. * WIDEBAND AMPLIFIERS A StINAT COMPANY * FAST ADC/DAC Teleco is a proven innovative company providing Measurement -While -Drilling (M.W.D.) services to * SEMI/CUSTOM ANALOGUE major oil companies worldwide. As a result of highly successful technical advances coupled with increased * FAST PULSE CIRCUITS international growth, we are experiencing a period of expansion. Presently we have vacancies for:- ELECTRONICS TECHNICIANS GOULD The successful candidates will possess practical e experience of digital and analogue as well as systems having formal qualifications such as ONC or equivalent We are located at Hainault which is on the edge of C & G qualifications in Electronic Engineering. the Green Belt close to all the facilities of London. Included in the total package of company benefits are Gould designs and builds Europe's leading competitive salary, contributory pension scheme and good working digital storage oscilloscopes. We offer good conditions. Applicants should realise that relocation to the Aberdeen area is essential, and working conditions, competitive salary, flexible that all positions are shore based. working hours and assistance with relocation. Removal assistance will be provided. Telephone: Mrs. Pat Lawson on Interested candidates should write enclosing a C.V. 01-5001000 stating salary requirements for the attention of:- GOULD INSTRUMENTS LTD. Miss F. Skinner, Assistant Personnel Manager (2485) TELECO OILFIELD SERVICES LTD. Electronics Barclayhill Place, Portlethen, Aberdeen AM. 4PF. Agency enquiries are not requested.

ELECTRONICS & WIRELESS WORLD MARCH 1985 )

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THE UNIVERSITY OF SUSSEX SCHOOL OF BIOLOGICAL SCIENCES Electronic Engineers -- Electronics Technician Grade 5 An electronics technician is What you want, where you want! required to work in the Experimental Psychology Group TJB Electrotechnical Personnel Services is a specialised appointments on an SERC research project on We have clients throughout Al and speech recognition. The service for electrical and electronic engineers. post is for two years in the first the UK who urgently need technical staff at all levels from Junior Technician instance. The successful applicant will work with the Laboratory to Senior Management. Vacancies exist in all branches of electronics and technical staff interfacing audio and digital devices to BBC micros allied disciplines - right through from design to marketing - at salary and to a VAX -11/780. Experience levels from around £6,000 -£20,000. with these machines would be an advantage, but some training will If you wish to make the most of your qualifications and experience and be given. we will be pleased to help you. Salary within the scale for move another rung or two up the ladder Technicians Grade 5 £6,581 - All applications are treated in strict confidence and there is no danger of £7,684 per annum, depending on age and experience. your present employer (or other companies you specify) being made aware Closing date for applications.) February Path 1985. Applications in writing to the of your application. Laboratory Superintendent, School of Biological Sciences, University of Susses, Faimer, Brighton BN1 90G. (24961 TJB ELECTROTECHNICAL Please send me a TJB Appointments Registration form: PERSONNEL SERVICES, EXPERIENCED AUDIO/ELECTRONIC ENGINEER 12 Mount Ephraim, Name Tunbridge Wells, Experienced Audio Electronic Engineer Address required for progressive company specialising Kent. TN4 8AS. in P.A. Studio Installations. Design 8 Servicing of Professional Audio Equipment. Digital experience an asset. Tel: 0892 39388 (861) (24 Hour Answering Service) Phone 01-609 8282 (2475'

Imperial Chemical Industries PLC Agricultural Division : Billingham : Cleveland Catalysts Group Micromerîtics Technologist The Catalysts Group of Imperial Chemical Industries PLC, Agricultural Division, requires an Experimental Officer working on the provision and development of micromeritic services for the Division. The job consists of operating and maintaining manual and automatic equipment for the measurement of surface areas, pore size distributions, mercury and helium densities of pellets and powders. Significant skills are required in the interpretation of the data obtained and in communicating these to the experimental and scientific staff of the Division. The work will be in a laboratory environment and also involves the use of computers for control, calculation and data presentation. The successful applicant must be self -motivated and capable of independent work. He/she should have a first degree in physics, physical chemistry or materials science and be interested in the utilisation of computers for improving the efficiency of the service provided. Interpretation of the results with respect to the particular material properties will be needed. Their relevance to the particular system being considered will need to be discussed with the customers of the micromeritics service. Previous experience with computers and electronics would be an advantage. Remuneration will be commensurate with qualifications and experience. The Company operates house purchase, profit sharing and contributory pension schemes and offers financial assistance towards ^iy removal expenses. 41110' Applications giving details of age, qualifications and experience should be sent as soon as possible to: Mr M AJ W Pegg, Personnel Department, Imperial Chemical Industries PLC, Agricultural Division, (2495) PO Box No.1, Billingham, Cleveland TS23 1 LB.

9.) ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com Appointments t t Dolby Laboratories Dolby Laboratories manufacture a range of professional audio noise reduction equipment which is used by major recording companies, the cinema industry and broadcasting authorities throughout the world. TEST DEPARTMENT SUPERVISOR Reporting to the Production Manager the person appointed will be responsible for planning the flow of products through the department, providing technical support and ensuring high quality. The 17 staff test and trouble -shoot analogue circuits to component level, using ATE where appropriate. The position, which is both demanding and rewarding, would suit a graduate engineer aged 25-40 with supervisory experience in a similar environment. PRODUCTION ENGINEER (ELECTRONICS) The person appointed will join a small team which is responsible for technical support to the production department as well as interfacing with sales and design engineers on product improvement and new developments. The successful applicant - aged between 25 and 35 - will be an electronics engineer with an enthusiastic, practical approach backed up a degree or HNC and several years experience in electronic equipment manufacturing. A keen interest in audio electronics and experience with ATE and CAM would be an advantage. Salaries will be commensurate with qualifications and experience and assistance towards relocation is given in suitable cases. The company operates a free life insurance and pension scheme. For application form write or phone: Sarah Kennedy, Dolby Laboratories Inc., 346 Clapham Road, London SW9 9AP. Tel: 01-720 1111 2474

HARROW HEALTH AUTHORITY Northwick Park Hospital & Clinical Research Centre. Watford Road, Harrow, Middlesex. Tel: 01-864 5311 ELECTRONICS TECHNICIAN Electronic Engineers UNIVERSITY OF SUSSEX (MPT Grade IV) Technicians Technician required to service and and Electronics calibrate a wide range of equipment used for medical, surgical and engineering Technician purposes. The successful applicant will In the Arts and Social Studies Area. Duties work closely with medical, nursing and will include maintenance and repair of other professional staff. The major part asking for installation They're and printers, computer terminals of the work involves basic maintenance and checking of wiring, installation of and repair of the equipment. computers, ordering and keeping stock of spare parts. An interest in computing is O.N.C. or equivalent and three years you in Alexandria. desirable. previous experience is the essential Salary within Grade 4 £6,106 - £7,024 per qualification for this post. Voluntary Service Overseas is looking for experienced annum, according to age and experience. Salary: £5404 - £7104, plus London Application form from Susan Cory -Wright, and qualified Electronic Engineers and Technicians to Weighting £623. work with and help train members of third world Personnel Office, Sussex House, University of Sussex, Falmer, Brighton For further details and application form Applications must be received by communities in Egypt (University of Alexandria Research BN1 9RH. please contact the Personnel Department, April, 1985. (P499) Centre) and in Sri Lanka (Chilaw Diocesan Industrial 10th Ext. 2001. Centre). Closing date: 6th March 1985 (2491) Applicants should be aged between 20 and 65, without dependants and willing to accept no more than the 'local' rate of pay. If you have the right qualities and experience and 're free to go. please believe you're needed you Civil Aviation College (Gulf States) DOHA, QATAR urgently! Required Soonest: (For more information, complete and return the now.) AVIATION ELECTRONICS INSTRUCTOR L University Degree in Electronics or Electrical Engineering or SOcoupon equivalent. 2. Qualified and Experienced in the Installation and Maintenance of m interested in volunteering. my Aeronautical Radio Systems and Electronics Air Navigational Aid qualifications or experience are V ÁRI( Ground Equipments. 3. Minimum ten (10) years teaching experience in an ICAO recognized training centre. SERVICE 4. Salary and allowance up to U.S. Dollars 3400 per month. Name Applications to: OVERSFAS The Principal Civil Aviation College (Gulf States) Address P.O. Box 4050 Why not? DOHA State of Qatar EIVW/3/85 (2489) Post to Enquiries Unit. Voluntary Service Overseas. 9 Belgrave Square.

London SW 1 X 8FW (S A E appreciated ) Charity No 313757 (2480)

ELECTRONICS & WIRELESS WORLD MARCH 1985 95

www.americanradiohistory.com EXPERIENCED CUT THIS OUT! AGENTS REQUIRED MAINTENANCE Clip this advert and you can stop hunting for your next For London & South/South ENGINEER appointment. We have a wide selection of the best East to sell PMR and Radio Required for Microwave. Micro appointments in Digital, Analogue, RF, Telephone Systems. Townhouse Studios. processor, Computer, Data Comms and Medical Elec- Apply in writing with c.v. to: tronics and we're here to serve your interests. Phone ARE Communications Barbara Jeffries, townhouse Studios, 150 Goldhawk Road, London W12. Call us now for posts in Design, Test, Sales or Field 01-992 9142 (247G) Service, at all levels from £6,000-£16,000. (2481) `Technomar& Engineering & 'technical Recruitment 11 Westbourne Grove, London W2. Tel: 01-229 9239. 119351 Carlton Television Carlton Television, part of Carlton Communications PLC, has vacancies for Broadcast Television Engineers to work on and maintain our range of state 1 u CAPITAL APPOINTMENTS LTD (tt of the art equipment to broadcast standards. 1 f THE UK's No. 1 ELECTRONICS AGENCY Experienced and time -code computer editing systems I ¡illlgl If you have HNC/TEC or higher qualifications and are and C -format one -inch VTR's would be considered looking for a job in design, test, customer service, technical an advantage. I I,I sales or similar fields: Salary by negotiation according to experience. I Telephone now for our free jobs list I We have vacancies in all areas of the UK Salaries to £15,000 pa Applications in writing only to: 1 Neil Wilson I 01 808 3050 Carlton Television (24hours) St John's Wood Studios I St John's Wood Terrace LTD I CAPITAL APPOINTMENTS LONDON NW8 (2477) 76 WILLOUGHBY LANE, LONDON N170SF I 1291) tlV. Your short circuit to a better career We are now looking for highly professional Electronics Engineers who want 1985 to be the most NOW SHORTLISTING: To Stuart Tait, their careers. Waiting on our sophis- Lansdowne Appointments Register, challenging year of Engineers ticated database are vacancies all over the country, Electronics Park House, 207-211 The Vale, with in: especially in high technology industries. And if you want experience LONDON W3 7QB to name your ideal position, our experienced advisers will Design/ Please send me a Lansdowne even make discreet approaches on your behalf. Development Appointments Register job finding pack. Joining Lansdowne Appointments Register is FREE Applications NAME and is as simple as filling in this coupon or calling us. We will Project Control then send you one of our highly developed profile forms, Technical Management ADDRESS which will enable us to accurately pinpoint the career move Test you seek. Quality Assurance Commissioning Over the last 12 years, we have helped literally Field Service thousands of people to further their careers. In fact, we've all posts are open to men and women and our service is for and joh-seekers. been so successful at finding the right jobs and the right completely confidential companies people that many companies talk to us before they even O1-743 bother to advertise vacancies - many never do! Lansdowne If you want to short circuit the system - contact us Appointments Register now, and join the people who have already found the fast Jobs for professionals: Professionals for jobs. route to a more successful career. G321 (2488)

96 ELECTRONICS & WIRELESS WORLD MARCH 1985

www.americanradiohistory.com THE PAPUA NEW GUINEA UNIVERSITY OF TECHNOLOGY Appointments DEPARTMENT OF ELECTRICAL AND COMMUNICATION ENGINEERING SENIOR TECHNICAL INSTRUCTOR Applications are invited for the above position which will be available from July 1985. Applicants should have a higher certificate/ diploma/degree qualification and relevant industrial experience. Preference will be given to candidates with a teaching qualification and PICCADILLY RADIO experience in digital communication systems.

Salary: Senior Technical Instructor I - K16,820, II (K1 = an Senior Technical Instructor - K17,870, Stg. seeks 0.9182). Level of appointment will depend upon qualifications and experience. The initial contract period is for three years. Other benefits include gratuity of 24% taxed at 2%, appointment and repatriation fares, leave fares ENGINEER for the staff member and family after 18 months of service, settling -in and settling -out allowance, six weeks leave per year, education fares and assistance towards school fees, free housing. Salary protection plan and medical benefits schemes are available. Detailed applications (two copies) w th to HNC/HND to perform varied tasks in a friendly and curriculum vitae together with the names and Qualified addresses of three references and indicating challenging environment. ILR2 salary plus shift allowance. earliest availability to take up appointment, should be received by: the Registrar. Papua New Guinea, University of Technology, Private Mail Bag, Lae, Papua New Guinea, by 30 March 1985. Apply:- Chief Engineer, Applicants resident in United Kingdom should also send one copy to the Association of Piccadilly Radio, P.O. Box 261, Commonwealth Universities (Appts) 36 Gordon Manchester M60 1Q11. Square, London WC1H OPF, from whom further general information may be obtained. (2520) Piccadilly Radio - An Equal Opportunities Employer (2498)

Broadcast Television Electronic Carlton Television Maintenance Engineer As a result of continual expansion, Carlton Television A vacancy exists in our videotape post -production has a vacancy for a broadcast Vision Control department for a suitably qualified person The Engineer, to work on operations both within our 2 applicant should have an appropriate acacemic studios and on Outside Broadcasts. qualification and be conversant with modern television post production equipment. MPC has a Previous experience of broadcast colour cameras and range of state of the art equipment such as ADO, associated equipment is essential. Mirage and FINS 4000. Shift working is required The salary will be negotiated according to experience. and remuneration will be based upon qualifica- tions and experience. Applications in writing only to: Please apply in writing only Neil Wilson with full details to John Beedle Carlton Television The Moving Picture Company St John's Wood Studios St John's Wood Terrace 25 Noel Street, London WI. (2484) L J LONDON NW8 (2478)

EALING HEALTH AUTHORITY F.W.O. Bauch Limited EALING HOSPITAL - GENERAL WING ELECTRONICS TECHNICIAN I A vacancy exists for an Electronics Major suppliers of professional audio equipment to the Technician in this Acute/Maternity Unit. Accountable to the Unit Works Officer the recording and broadcasting industries have vacancies for successful applicant will be able to demonstrate technical, supervisory and SERVICE ENGINEERS in their well equipped professional professional abilitiegand will be audio laboratory in responsible for this E.M.E. Department Boreham Wood. which serves the District. Applicants should possess an H.N.C. or equivalent in Relevant electronic experience and an interest in sound Electronic Engineering and will be paid on the following scale: Applicants must recording would be an advantage. possess a current driving licence. £9925 - £11489 including London in Weighting. Apply writing with full C.V. to Christine Melhuish For an informal discussion contact Mr C H Jones, Unit Works Officer, Personnel Department Tel: 01-574 2444 Ext. 304/5. Job description and application forms available from Personnel Department, Ealing Hospital - FW.O. Bauch Limited Genereral Wing, Uxbridge Road, Southall, Middx. 49 Theobald Street, Boreham Wood, Hertfordshire WD6 4RZ Tel: 01-5742444 Ext. 344. Closing date for receipt of application Telephone 01-953 0091, Telex 27502 forms 13th March 1985. (2502) (2497)

ELECTRONICS & WIRELESS WORLD MARCH 1985 97

www.americanradiohistory.com Appointments Telecommunications Engineering

UNIVERSITY OF LIVERPOOL Technicians COMPUTER LABORATORY Openings in Servicing and Maintenance TECHNICIAN GRADE 5 Up to £8,873 to undertake installation and repair work. Ability to fault diagnose and repair Our business is to install and electronic equipment (both digital and analogue based) to component level maintain the communications expected. Opportunities also exist for participating in work of small team, equipment used by the Police developing advanced micro -electronic and Fire Brigades in r interfaces includin Ethemet Products. England Experience in micro -electronic and Wales - some of the latest construction desirable. Successful candidate will be expected to plan his own you will find in operation work schedules based on objectives anywhere. travelling defined by the Section Manager. Progress reporting, indentification of potential We have a number of vacan- will norm- delays and record keeping are important aspects of the work. cies at our Service Centres in various ally be in- Applicants should possess a current parts of the country, for Telecommuni- volved. Reg- driving licence. O.N.C. or appropriate equivalent is minimum qualification plus cations Engineering Technicians with istered disabled seven years relevant experience. practical skills in locating and diagnos- persons can of Salary within range £6581 - £7684 per a apply. annum. ing faults in wide range of equipment course Application forms may be obtained from from computer-based data transmission The Home Office is an equal the Registrar, the University, P.O. Box to FM and AM radio systems. opportunities employer. 147, Liverpool, L69 3BX. Salary will be on a £6501 Quote Ref: RV/956 (25111 The work provides excellent scale opportunities for extending your techni- to £8873 a year with generous leave cal expertise, with specialised courses allowance and pension scheme. and training to keep you up to date on Good prospects for promotion. MORE JOBS developments and new equipment. If you are interested in work- There are also opportunities for day ing with us, please write for further FOUND IN release to gain higher qualifications. details and application forms Applicants, male or female, quoting reference WW/1 to: must be qualified to at least City & Miss M Andrews, Home Office, WireIgarrolld Guilds Intermediate Telecommuni- Directorate of Telecommunica- cations standard a tions, Horseferry House, Dean Remember to look at our and possess current driving licence. Some o RyleStreet, LondonSW 1 P2AW. "Appointments extra" 12 517) supplement for four more Directorate of pages of vacancies. í Home Office Telecommunications

AMPEX is a company at the forefront of magnetic recording technology, which manufactures Professional Video Equipment, Instrumentation Recorders, Disk Drives, Terminals and Magnetic Media. AMPEX INTERNATIONAL TRAINING, based in Reading, England, is currently expanding and there are several vacancies for Instructors to conduct quality maintenance courses on AMPEX products. Applicants should be men or women who have experience in one or more of the following areas: Digital Processing, Professional Video Recording, Digital Magnetic Recording, Microprocessor Based Equipment. Teaching experience is not essential, as appropriate training will be given. An attractive salary is offered, together with the usual large company benefits. AMPEX For application forms, please contact: INTERNATIONAL Maureen Brake, Personnel Department, or John Watkinson, Training Manager. TRAINING

AMPEX, ACRE ROAD. Reading (0734) 875200 READING RG2 OOR. Ñ 98

www.americanradiohistory.com picRProfessionveal First choice for job hunters & Exeçutï Recruitment

Component Development Field Service Engineers N Herts £13,000-£14,500 tax-free Iraq High-technology market leaders, my clients' advanced systems incorporate World leader in hospital laboratory automation, producing broad range of the very latest component developments, created by themselves and in scientific/medical instrumentation for use in clinical pathology, needs conjunction with major manufacturers. additional Engineers to install systems, attend to routine/emergency maintenance and assist in training. A two-year renewable contract on Component Engineers single status, it demands t he expertise of experienced Engineers aged 25-35, To advise designers on applications and evaluate new types. Electronics qualified to HNC Electronics with a background in the servicing of qualification, knowledge of component systems (BS9000, MIL, STDs), computer -controlled equipment, ideally medical instrumentation. People experience in electronics test, evaluation or defect analysis. Knowledge of with laboratory experience in biochemistry or haematology and knowledge hybrids, packaging, interconnections, material properties, HP45/IEEE of electronics also considered. Tax-free salary, bonus, free furnished bus programming, radiation hardness an advantage. accommodation, car, medical and life insurance, two months' annual leave, air fares paid. Induction training in France. Team Leader - Send full cv and passport size photograph to Colin Hodsdon, PER Overseas, 4th Floor, Rex House, 4-12 Regent Street, Component Evaluation London SW 1Y 4PP. To head team dedicated to hybrid evaluation and defect analysis. Qualifications and expertise as for Component Engineer. Section Leader - High -Tech Expansion Electrical Standards Newcastle-upon-Tyne To head laboratory team responsible for calibration of all electrical/ Expansion, consolidation and major market initiative with innovative electronic instrumentation, development of new methods, and liaison with high-tech product range are together creating a number of new key external calibration labs. Electrical/electronic apprenticeship, HNC/HTC appointments with this successful Tyneside company, part of a publicly plus knowledge of concepts of traceability and compliance with quoted group, assembling electronic and electrical light current control and MOD/BCS requirements. monitoring devices. Negotiable salaries and large company benefits, including relocation to North Hertfordshire. Send full cv stating salary requirements, to Lynda Bubb, PER, 56-62 Park Senior Software Development Engineer Street, Luton LU13JB. To update programs for requirements of computer remote control systems to MINOS standard. Qualifications: experience in real-time data programs using Coral 66. Knowledge of peripherals an advantage. UK travel. Test Equipment Engineers To £8,900 Merseyside Microprocessor Hardware Engineer Major new contracts at leadingelectronics manufacturer are creating new To develop micro -based equipment for extreme environments. key appointments for Test Equipment Engineers. HNC or preferably Qualifications: degree in electronics plus D + D of microprocessor degree-qualified in electrical/electronics engineering, you must have had equipment for mining industry. Experience of software writing for 8-bit experience of software and hardware application and procurement related processors an advantage. to large-scale computer -controlled test equipment. Knowledge of circuit logic and ATE programming techniques including high level Machine Code and Assembler languages would be an advantage. The company Product Manager - offers the full range of benefits you would expect of a large, successful organisation, together with excellent working conditions. Generous Control & Monitoring Devices relocation assistance will be available. To develop remote control and monitoring plant for use in hazardous Send full cv to Howell Williams, PER, 3rd Floor. Graeme House, environments, eg, mining and petrochem industries. Qualifications: degree Derby Square, Liverpool L2 7SP. in electronics plus experience in similar role, knowledge of microprocessor equipment development and applications, ideally including exposure to mining industry needs. Systems Engineers Negotiable salaries, pension/life assurance, generous holiday allowances, excellent prospects. Attractive salary Lake District area Phone Aidan Lynn, PER Newcastle, on (0632) 618418, for job description Leader in design, development, testing and manufacture of advanced and application form. electronic systems needsadditional Systems Engineers for multi - disciplined teams involved in all aspects of systems design and implementation, including move towards hypertechnology programmes. Degree or equivalent in relevant discipline plus two years' practical experience, ideally including top -down structured design. Major JOB HUNTERS international group package, with relocation expenses. Send full cv to Pam James, PER, Victoria House, Ormskirk Road, This is a small selection of our current vacancies. For free weekly details Preston PRI 2DX. of over 450 executive -level appointments, phone (0742) 704585, or Test & Installation Engineers complete this coupon and send it to PER, Moorfoot, The Moor, Sheffield S I4PQ. 24 hour answering service (0742) 750197. Attractive package Cheshire New technological era and expansion are creating key appointments with Name: highly successful international leader in analytical instrumentation for earth sciences, nuclear industry, environmental pollution control, high Address. purity metals and semiconductor industries. Role includes test, commissioning, installation and servicing of systems on -site in UK and overseas. HNC Electronic Engineering plus two years' experience as Occupation technician, installation engineer, test or electrical engineer or graduate in physics, chemistry or metallurgy with related experience. Knowledge of Date of Birth: computer software/applications an asset. Salary level: Send full cv to Dorothy Thompson, PER, 75 Sankey Street, Ref: E&WW Warrington WA ISL. (2503)

ELECTRONICS & WIRELESS WORLD MARCH 1985 gt

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:..,+:.:_4 ,..::...:.::..:. . ., : .:.¢.,.:.:.>n.,£::<<::....:...... :.:,>...... __>:;: :.. ... :v<.., . .. :>á :: e> £20.00-P/HR. THE UNIVERSITY OF LEEDS 1) Microwave Amplifier Design ELECTRONICS Canada. 6 months +. £20 P/HR. Manager, Production 2) High Frequency Trigger TECHNICIAN Amplifier Design. 100 MHZ. Essex. 6 months +. Dept. of Physiology Engineering Services 3) RF Designers. M.O.D. Herts/ Required to assist in the construction of Essex. 6-12 months. (2516) maintenance of electronic equipment associated with research and teaching of Phone or write: biological studies (under the supervision of We have established a new management Roger C.Eng., M.I.E.E., M.I.E.R.E. Howard, the electronics engineer). Must be capable of position in the Technical Operations Department CLIVEDEN CONSULTANTS working from circuit diagrams and sketches. O.N.C. or 92 The Broadway, Bracknell, Berkshire Applicants should hold equivalent e at our Nottingham Production Centre - one of the Tel: 0344 489489 qualifications and have 3-5 years relevant in experience (including training period). most modern studios the UK. Salary will be grade 3 £5,399 - £6,325 p.a. The person appointed will be responsible for CLIVEDEN Applications stating age. qualifications and full experience, together with the name and the CAR, VT and Vision Control sections and for address of 2 referees, should be addressed to Mr. S. Stainthorp. monitoring their technical performance. Dept. of Physiology. Medical and Dental Building. We want someone who combines engineer- University of Leeds. Leeds L52 9IT. 125151 ing competence with managerial ability- qualified to at least HND or equivalent with a minimum of five years engineering experience with a studio centre or an equipment manufacturer: experience at or above supervisory level is essential, with the BCS LABORATORY DEPUTY HEAD skill to organise and control technical resources in Due to expansion we have a vacany for on experienced a cost-effective manner. An understanding of standatds engineer to carry out calibration on DC and LF TV production an asset. operations would be instrumentation in our laboratory, which is approved by Candidates' likely age range will be 30-40. the British Calibration Service. The salary and benefits are attractive and This position would ideally suit someone in the reflect the ability and experience required for the calibration gield wishing to futher their career prospects. position. If you have the necessary qualities, why Experience in this type of environment is a necessity. not send us your CV? Personnel Department, An attractive salary, pension and BUPA benefits will be Central Independent Television plc, offered, also relocation expenses where applicable. East Midlands Television Centre, Apply in writing giving details of employment to date: Nottingham NG7 2NA. Mr. J. Macalister An equal opportunities employer. GMR Ltd., Unitig, (25, 0) Salisbury Square, Radford, . Nottingham. i2518t . CCENTRAL mee>

SATELLITE RECEPTION RESEARCH ASSISTANTS BORED ? job! Monitoring Service Then change your 1) Test Engineer With the advent of satellite communications, broadcasting and news agency organisations To work on inter active video are switching from conventional means to satellites for their transmissions. Satellite Recep- systems and data acquisition equipment. Berks. To £10,500. tion Research Assistants will be involved in the Monitoring Service's work in this field. 2) Field Service Engineers Duties include frequency scanning and the compilation of transmission schedules. To work on mobile radio communications. Berks. To £7,500. in communications with C and G Intermediate Telecommunications Extensive experience 3) Test Engineers Technicians Certificate or equivalent qualification and a thorough grasp of satellite Working an analogue digital control communications are essential. Knowledge of major broadcasting systems, familiarity with systems for radio and news agency transmissions and the ability to recognise a range of languages an advantage. microprocessor equipment. Surrey. To Applicants will be required to take written tests and appointment will be subject to 4) Service Engineer satisfactory hearing tests: Shift work involved. To work on computer peripheral equipment. Berks. To £2500 Salary £7,867-£9,761. Plus 10% shift allowance. Based Caversham Park, Reading. 5) Technical Author Relocation expenses considered. Naval hardware systems. Surrey. To £11,000 Write or telephone immediately for application form (enclosing addressed, foolscap 6) Junior Electronics Development envelope and quote ref. 2037/WW), to Senior Personnel Officer, BBC Monitoring Service, Involved in the design of colour and Caversham Park, Reading, Berkshire RG4 STZ. Tel: (0734) 472742. Ext. 212. monochrome TV monitors. HNC/ HTC+. Bucks. To £10,000. Hundreds of otter Electronic We are an equal opportunities employer and Computer vacancies to £12,500 Phone or write: Roger Howard, C.Eng.. MILE., M.I.E.R.E. CLIVEDEN CONSULTANTS 92 The Broadway, Bracknell, Berkshire

Tel: 0344 419489 (1640 ) o (2507) CLIVEDEN

100 ELECTRONICS & WIRELESS WORLD MARCH 1985

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THE SERVICES SOUND AND VISION CORPORATION DESIGN AND BROADCAST AND DEVELOPMENT ENGINEER ELECTRONIC ENGINEERS Experienced engineer required to join small electronics company involved in Required for Broadcast operations and engineering in the Services Sound design and manufacture of telecomms products and Vision Corporation for BT and other PeT which provides radio and television services to authorities. the British Forces and their dependants abroad. Candidates (preferably Applicants should have experience in line aged 22 - 35) should be educated to HND standard in electrical and equalisation equipment, filters, SMPS electronic engineering and have work experience in the broadcasting or and automatic testing using related industry. microprocessor techniques. Qualifications to degree or HNC with suitable experience. Attractive salary + for your The work, often overseas, includes the operation, maintenance and usual benefits to right person. installation of the full range of professional radio studio equipment and Application to include current c.v. to: Medium Wave and VHF broadcast transmitters. Kenton Research Ltd. Europe Trading classified Estate, Erith, Kent DAS 1QL Telephone: (032 24) 419 33 Good salary and allowances paid together with fringe benefits. There are (2519) adverts also prospects of promotion to higher grades and opportunities for training and transfer to Television and other departments of the SSVC. ring Please apply in writing to: Mrs Anna Sive, Personnel Officer The Services Sound and Vision Corporation, Chalfont Grove Narcot Lane, Gerrards Cross, Bucks SL9 8TH (2504) Ian Faux

B10 -EN G1NEER1N G 01 661 OPPORTUNITIES 1N 3033 SAUDI ARABIA General Arabian Medical and Allied Services Ltd. are management consultants and agents for the recruitment of staff to the Riyadh Al Kharj Hospital Programme in Saudi Arabia. The programme comprises three hospitals including the 600 bed Riyadh Armed Forces Hospital and provides a very high standard of health care to members of the Armed When replying to classified Forces of Saudi Arabia and their families. advertisements, readersare The Department of Medical Physics and Bio -Engineering has programme - wide responsibilities and with a mainly British staff of more than 40, is the recommended to take steps largest department of its kind in the Middle East. Avery wide range of to protect their interests clinical support and development work is undertaken by our well qualified before sending money professionals. Successful candidates will have the opportunity to widen their experience in a busy modern department with excellent facilities (2519) allowing them to achieve the high standard of work expected of them. Further expansion of the department's activities, including a commitment BUSINESS OPPORTUNITY( to provide technical support for medical equipment on the Kingdom's fleet of Lockheed C-130 Hercules "flying hospitals" and air ambulances has SOUTH SHROPSHIRE DISTRICT COUNCIL created the need for additional qualified bio -engineering technicians SWITCHBOARD AND MEDICAL ELECTRONICS TECHNICIANS TELEPHONE INSTALLATION The Council need to replace their present ANAESTHETIC EQUIPMENT MAINTENANCETECHNICIANS switchboard arrangements and telephone installation for the Council Offices, Stone House, SALARY c £16,230 -- £18,234 pa tax free Incl. bonus Corve Street, Ludlow. A specification giving details of the Council's The above posts are offered on the Medical Physics Technical Officer requirements and a form of tender is available from the undersigned. (Bio -Engineering) grade, equivalent to the NI -IS grade Ill MPT. Qualifications Completed forms of tender must be received by to OTEC or equivalent level is essential; HTEC and/or some years not later thon 12 noon on Monday 18th March of 1985. relevant experience is highly desirable. G. Collet, Chief Executive, Stone House, Corve Sheet, Ludlow, Shropshire. There are also Locum positions available for medical physics technical Tel: Ludlow 2381 Ext. 22. officers fora period of not less than three weeks. !2S

Benefits ARTICLES FOR SALE Contracts are normally offered for a two-year initial term and include free fully furnished accommodation; four weeks leave after every six DRIOTWICH STANDARD months' service; free air fares (including leave flights); free health FREQUENCY RECEIVER care and extensive recreational facilities. The bonus will be paid on completion of the contract. Salaries for these single status positions are paid in Saudi Riyals and the sterling salaries quoted are calculated at the current rate of 4.1 Saudi Riyals =El. For further information apply with a detailed C.V. or telephone for an application form. Susan Grice, Recruitment Officer, Outputs, 1MHz, 10MHz Phase locked crystal oscillator. Complete GAMA INTERNATIONAL LTD., with ferrite rod aerial, usable throughout 6 Duke of York Street, London SW 1Y 6LA. U.K. Now available in updated version. £185 00 Telephone: 01-839 6843. R.C.S. Electronics, Wolsey Road, Ashford, (2508) Middx. Phone 53661. (2656)

ELECTRONICS & WIRELESS WORLD MARCH 1985 101

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ARTICLES FOR SALE WANTED SERVICES

BRIDGES waveform/transistor analyysers. Cali- brators, Standards. Millivoltmeters. Dymamome- PCB Fault Location and ters. KW meters. Oscilloscopes. Recorders. Sig- Repair. Jaecrow Systems nal generators - sweep, low distortion, true WANTED Services, 29/31 Lower Coombe RMS, audio, FM, deviation. Tel. 040 376236. (1627) Test equipment, receivers, Street, Croydon, Surrey CR9 1 LX, valves, transmitters, com- Britain's leading maintenance cable and company, now offers a fast board QUARTZ CRYSTALS OSCILLATORS AND ponents, diagnosis and repair service UK stocks of standard FILTERS of all types. Large electronic scrap and quan- and overseas, using the latest items. Specials supplied to order. Personal and export orders welcomed SAE for lists please. tity. Prompt service and Portable Battery or Mains Oscilloscope. SE Laborato- ATE. Ask for full details, without OEM support thru:- design advice, prototype cash. Member of A.R.R.A. ries 111 Oscilloscope - Solid State - General pur- obligation Ring: 01-680 9191. pose - Bandwidth DC to 18/20MC/S at 20M V/CM - quantities, production schedules. Quote ref: EW385 (24711 Electronics. Merriott, Somerset TA16 Sual Channel - Golledge Rise time 19NS Calibrated Sweep Calibrator - 5NS. Teh 0460 73718 (2472) - - M&BRADIO Display 10CMS=8CMS - Power AC - 95 Volts to 100- 86 Bishopsgate Street 190 Volts to 260 or 24 Volt DC battery - Size. Leeds LS1 4BB W.25.5.CM - 1125.SCCMS - 56CMS Deep - PROFESSIONAL DESIGN SERVICE. Ana- ENCAPSULATING EQUIPMENT FOR.coils, WT11.4KGS -Carrying handle - Tested in fair condi- logue/RF circuit/System design. Specialising in 435649 £120.00. microwave oscillator components, degassing silicone" 0532 tion with operating instructions amplifier, and network transformers, design. MOTOROLA 6805/6809 series micropro- rubber,. resin, epoxy. Lost wax casting for brass,, (99561 bronze, silver, etc. Impregnating coils, transfos' cessor design/development capability. All work Vacuum equipment, low cost, carried out to a high standard by competent profes- mers, components. sional engineers. Trontech Electronic Design Ser- used and new. Also for CRT regunning metallic-. vices Ltd., Unit 8B, Rose Industrial Est., Boume & Development. Barratts, Mayo ing. Research End, Bucks. 06285 28835 (2439) Road, Croydon CRO 2QP. 01-684 9917. (9678) WANTED MORSE READING PROGS.Work on clean sig- SURPLUS ELECTRONIC TURN YOUR SURPLUS i.cs transistors etc. into nals without hardware interface. ZX81 1K UNEX- cash,unrnediate settlement. We also welcome the PANDED MEMORY. Translated code with word COMPONENTS AND opportunity to quote for complete factory clear- and line spaces for easy reading Automatic scroll EQUIPMENT ance. Contact COLES-HARDING & CO, 103 action. £7 incl. (2532) South Brink, Wisbech, Cambs. 0945 We also welcome the opportunity to quote for 584188. (9509) complete factory clearance B. BAMBER ELECTRONICS 5 STATION ROAD, LITILEPORT, CAMBS. Latest Bulk Government Release - Cossor Oscillo- DESIGN AND DEVELOPMENT SERVICE. RF Phone: Ely (03531 860185 scope CDU150 ( CT531/3) £150 only. Solid stale general transmitters and receivers. Telemetery U.H.F. OPTOELECTRONICS to 35MHz at 5MV/CM Dual 12483) purpose bandwidth DC - V.H.F. Anologue and digital circuits, control sys- (8.10cm) Full Channel - High brightness display tems. Full manufacturing facilities. RCS Electron- DATA BOOK 1984 base with gated mode Risetime 1085 delayed time - Dr. graticule Beam finder Calibrator ics, Wolsey Road, Ashford, Middx. Phone Eric Price by Texas £6.00 - Illuminated - - Falkner on 53661. (2637) 1KHz squarewave - Power 100 - 1208.200V - 250 DIGITAL ELECTRONIC CIRCUITS * MICROCOMPUTERS volts AC - Size W 26CM - 41 CM deep - WT 12.5 K.G. colour blue protection cover front by N.M. Morris carrying handle - - & SYSTEMS polarized viewer and camera adaptor plate FOR PCB PRICE: £5.45 * PERIPHERALS containing THE BEST SERVICE - probe (1) - Mains lead. Tested in Fair condition with AVAILABLE * INSTRUMENTATION operating instructions - £150.00. MICROELECTRONICS: offer, phone, A PRACTICAL INTRODUCTION by For fastest, best CASH Communication Recievers. Racal 500KC/S to 30MC/S oa,cuit Design & Development Analogue R.A. Sparkes PRICE: £8.50 in 30 bands 1MC/SWIDE - RA17 MK11 £125. RAt7L Digital and COMPUTER APPRECIATION £150. RA117E £200. New Metal Louvred Cases tor *Artwork Layout above £25. All receivers are air tested and calibrated in SOLDERING IN ELECTRONICS by Oxford (0865) 55163 PCB artwork layout and mechanical detailing. P.O. with dust cover operation R.J. Klein Wassin Wassink PRICE: £51.00 our workshop - supplied - approved standard. Telex 838750 instructions - circuit - in fair used condition. Racal (24921 OPTICAL FIBER COMMUNICATIONS Synthesisers (Decade frequency generators) MA350B *Board Manufacture Solid State tor use with MA79 RA217 - RA1218 Prototype to semi-production, excellent rates. BY G. Keiser PRICE: £9.50 - - Etc £100 to £150. MA250 - 1.6MC/S lo 31.6 MC/S £100. MA1350 for use with RA17 receiver £100. *Wiring & Assembly DIGITAL IMAGE ANALYSIS ARTICLES FOR SALE MA259G Precision Irequency standard 5MC/S - PCB assembly, wiring and cable forming. Flow solder- by S. Levialdi PRICE £26.00 1MC/S - 100KHz £100 to £150. Panoramic Adaptor ing facilities available. RA66 £150. RA137 and RA37 £40 to £75 LF convertors *Test IC DESIGN & VLSI 10 to 980KC/S. RA218 Independent SSB unit £50 RA98 SEMI -CUSTOM Full test facilities available. by P.J. Hicks PRICE: £13.50 Eurocard Power Supplies SSB-ISM Covertor £50. RA121 558-ISB convertor £75. SBB EC964/7K Solid stale - single channel - - One or all services available. 5v 4 1A, 1.5A, 3A, and 5A 400 to 535KHz INTRODUCTION TO MOS LSI mains or battery -1.610 27.5 MC/S and Please telephone Chelmsford DESIGN by J. Mayor PRICE: £18.50 Options: ±12v G 100mA for RS232, £100 with manual Plessey PR1550 Solid Stale 6OKC/S 102451 357935, or write to HCR 30MC/S £400. Creed 75 Teleprinters Fitted tape The Industrial Unit, 12 or 15v main output, - - Electronics, Crowbar, for 50 and 75 bauds 'Molts AC Road, Chelmsford. HANDBOOK OF BATTERIES & punch and gearbox - Parker Front Panel with IEC mains SKT. supply - in original transport tray sealed in polythene 130nins from Liverpool Street St) (1169) FUEL CELLS by D. Linden PRICE: £63.00 Teleprinter con- Prices from £15 for IA kit (£23 built) - lik new £15EA. Redilon 1711 Audio vertor receiver solid state - supply 110 or 240AC - THE DESIGN & DRAFTING OF + VAT for details contact: Made for use with above teleprinter enabling print-out DESIGN AND MANUFACTURE. ANALOGUE, by D. Lindsey of PRINTED CIRCUITS Sleevemain Ltd., dept WW, P.O. Box of messages recieved from audio input communica- DIGITAL, RF AND MICROWAVE CIRCUIT AND PRICE: £41.50 tion receiver £15 with circuit tested. Redilon TT10 Con- SYSTEM DESIGN. Also PCB design, mechanical 512, Windsor, Berks SL4 4NU. (2501) but includes transmit facilities £20. vertor as above design and prototype/small batch production. Ad- stocks always changing Tektronix - * ALL PRICES INCLUDE Oscilloscopes - enmore limited, 27 Longshot Estate, Bradmel, 465 100MC/S £750. FM Recorder Sanghmd Sabre POSTAGE - Basks. Tel: Bracknell (0344) 52023. (656) * 111 14 channels £350. Transtel Matrix printers - AF11R- S level Baudot Code- up to 300 Roods - for 65002 CMOS MICROCONTROLLER. print out on plain teleprinter paper £50 to £100 Trans- SMALL BATCH PCBs, produced from your art- THE MODERN telAHllR - As above but also 8level ASCII (CCITT No Uses BBC Computer as host. Boild stand- new £100. Army field tele- work. also DIALS, PANELS, LABELS. Camera 2 and CCITT No. 5) Like work undertaken. FAST TURNAROUND. De- alone controllers simply quickly. Bare phone sets. Type F - L and J - Large quantity in stock Winston Promotions, 9 Hatton Plaste, London boards or built & tested. Large s.a.e. for. £6 to £15 depending on type and quantity P.O.R. Don tails: BOOK CO. 8RU. Tel. 01-405 412710960. or technical manual £2.50: Nikam' 10 Telephone Cable - half mile canvas containers ECIN (9794) BRITAIN'S LARGEST STOCKIST details £20. Night viewing infra -red AFV periscopes Twin Lacey - of British and American Electronics Ltd 25 Suffolk Drive. Eyepiece - 24 volt dc supply £100ea. Original cost to Technical Books Green. Wilmslow Cheshire SK9 government over £11 000ea. Static inventors - 12 or V11)Ell DESIGN, develupmeul :nid consultants 4DE (2512) 24 volt input -240 volt AC sinewave output -various delay lines. Whirs.s. utter I rirs and amplifie s P.O.R. XY Milers and pen recorders various wattages design. drrel,,pment ,nid manufacture full test 19-21 PRAED STREET - P.O.R. Ferrograph series 7 Tape recorders mono £100, stereo £150. Signal Generators various - Meddles. l,mtan Faraday Trchnology Ltd.. Must LONDON W2 1 NP TF995/A3 £60. TF801 D/Bs -10 M C/S to 485M C/S £90 2 Iirawpton hulustnul Estate, Newcastle. TF144H/A4 £90. TF1060/2 £60 HP606A - £90 £140 0t,dforrl'hlre- Ter Newcastle 1117821 1)615111. Telephone: 01-402 9176 Sullivan Decade capacitor £49, FM/AM Genera- HP608 £50 HP614A £100 HP618B £100 HP62OA £100. meter £100 121511 Closed Saturday 1 p.m. tor £89. Sweep Generator (TV) £69. Thermocou- Marconi TF106413/5 £100 TF791 Deviation ples £2.50 ea. Chan Recorders, 2, 6, 20 channel. TF893A Power meter £50 Aerial mast assembly 30ft Please allow 14 days for 1611 whip aerial to mount on top - Data Logger. Anemometer. Small earboxes £5 ea. high complete with guyropes - insulators - Base and Spikes etc.. in heavy reply or delivery Dexion Guillotine £18. Valve testers. Ignition Ana- duty carrying bag - new £30. Racal frequency counter 12245) lyser £39. Centrifuge. Wow/Flutter meter. W -K IMPROVE YOUR PROSPECTS Type 836 £50 Tektronix plugs -ins -1 Al £ 50, 1A2 £40. micrometer Video Oscillator. Large stage, oper- 1A4 £100 M£50. All items are bought direct from H.M. ated microscope £89. Stereo headsets £6. Tek- Government being surplus equipment: Price is Ex with skills that employers want - learn VINTAGE VALVE SPARES - Valves, Radios, tronix Calibrator/Time Mark Generator £79. Cali- works. S.A.E. for enquiries. Phone for appointment the easy way with modern home study Amplifiers, Service Data. Antique Wireless bration Digital Voltmeter £85. Vibration Analyser for demonstration of any items. Also availability or Courses from Ideal Schools. Newsheet sample upon request. Mail Order Only. £65. Film Processor £75. Matrix Programmer £30. price change. V.A.T. and carriage extra. Vintage Wireless Co., Cossham Street, Mangots- Cassette Micro -manometer £49. Bransom Ultra- MODERN ELECTRONICS Siren Proportional Temper- field, BRISTOL BS17 3EN. Tel: 0272-565472 sonic Generator £29. TRADE AND QUANTITY Train for success in the fastest ever Distortion Meter £75. EXPORT (2471) ature Controller £45. Colour DISCOUNTS GIVEN growing industrial sector. TSR Simulator Main Alternator Control £45. Dyna- tron Pulse Analyser £39. Stabilised PSU's Creed JOHNS RADIO (0274) 684007 COMPUTER PROGRAMMING Spot-welding Heads, WHITEHALL WORKS, CALCOMP FLAT bed plotter 8" X 6" ex Teleprinter Terminal £65. The demand for Programmers is capacitance, D.C., etc. welding, thermocouples, 84 WHITEHALL ROAD, increasing constantly -don't miss out! ministry hever beem used since with con- circuit connections. dissimilar metals etc. etc. EAST BIRKENSHAW, BRADFORD For free booklet write today to troller and all cables and plugs day 01-878 £45. General Radio UHF Admittance meter £25, BD11 2ER (2774) 948 1049 (2513) Multiple Battery Substitution PSU £35. Surface 2090 eve/w.e. IDEAL SCHOOLS Guage (Micro -inches) £29. Switched 1,2,3 4,5 KV EHT Supply £30. etc. etc. WANTED: REDUNDANT TEST EQUIPMENT - °,(Ref.EW2) RECEIVING AND TRANSMITTING EQUIPMENT - T All standaro IDEAL . WAVEGUIDE, Flanges and dishes. VALVES - PLUGS - SOCKETS SYNCHROS sizes and alloys (new material only) from stock. ETC. ;tEW Special sizes to order. Earth Stations, 01-228 040 376236 (2016) (2743) ! Tel:041-248 5200 7876, 22 Howie Street, London SW 114AR. (2099) 102 ELECTRONICS & WIRELESS WORLD MARCH 1985

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WANTED: Ex. -RAF Air - publications, CIRCOLEC manuals, ect., from 1938 onwards relating THE COMPLETE ELECTRONIC SERVICE to transmitters - receivers, navigation TW ELECTRONICS LTD Artwork, Circuit Design, PCB Assembly, Test & Repair Service, Q.A. equipment and radar. Excellent price paid. THE PCB ASSEMBLERS Consultancy, Prototypes, Final Assembly. Full PCB Flow Soldering M. Gee 29 Studland House Aston Street Service. London E14 7NL Phone 01-254 9083 even- More and more companies are investi- gating the advantages of using a profes- Quality workmanship by professionals at economic prices. ings. (2514) sional subcontractor. Such an undertak- Please telephone 01-646 5686 for advice or further details. ing requires certain assurances. WANTED: Recording Equipment of all ages TAMWORTH MANOR TW are able to satisfy all of them - and variety. Microphones, outboard, etc. Dan quality, competitive pricing, firm delivey 302-310 COMMONSIDE EAST, MITCHAM Alexander 965 Hilldale Berkeley, Ca. 94708 and close co-operation with the cus- (1391) USA (415) 5271411 (2493) tomer. Assembled boards at 100% inspected before flow soldering and reinspected SURPLUS STEWART OF READING after automatic cropping and cleaning. E C COMPONENTS Every batch of completed boards is is- We offer good prices for test equipment, 110 WYKEHAM ROAD We buy large and small parcels components, redundant computers, READING RG61PL sued with a signed certificate of confor- mity and quality - our final assurance. of surplus I/C, transistors, capa- PCB's connectors. Immediate settle- TEL NO: 0734 68041 ment. For further details, contact us at our new citors and related electronic works: stock. Immediate settlement. TIMEBASE TOP PRICES PAID FOR ALL TYPES OF SURPLUS Blenheim Industrial Park Tel: 01-208 0766 94 Alfriston Gardens Bury St. Edmunds Sholling, Southampton SO2 BFU TEST EQUIPMENT, Telex: 8814998 COMPUTER EQUIPMENT, Suffolk 1P33 3UT Telephone: 107 031431 323 (2491) COMPONENTS Telephone: 0284 3931 (1466) 11832) etc. ANY QUANTITY. (2616) FREE P.T.H. PROTOTYPE of the finest quality with EVERY P.C.B. artwork designed by us. Com- BUSINESS OPPORTUNITY petitive hourly rates, and high standard of work. TO MANUFACTURERS, WHOLESALERS Halstead Designs Limited, 34, High St., Halstead, BULK BUYERS. ETC. PROFITABLE DISTRIBUTORS of spe- Essex. Tel. (0787) 477408/474554. (2126) electrical and electronic service cialised VALVES, PROJECTOR Lamps, 6000 types, list LARGE QUANTITIES OF RADIO. TV AND tools and equipment, catering equipment 75p, world wide export. Cox radio (Sussex) Ltd., and hardware for sale. Profits c. £10,000 The Parade, East Wittering, Sussex. Phone ELECTRONIC COMPONENTS FOR DISPOSAL, p.a. Reply Smallfield, Cody & Co, 24 Port- (0243) 672023 (1991) SEMICONDUCTORS, all types, INTEGRATED CIRCUITS, TRANSISTORS, land Place, London WIN 4AU. (2495) DIODES, RECTIFIERS, THYRISTORS, etc. RESISTORS, C/F, M/F, W/W, etc. CAPACITORS, SILVER MICA, POLYSTYRENE, C280, C296, DISC CERA- The Publishers take all IBM MICS, PLATE CERAMICS, nrpps etc. reasonable care to ensure that i:;;:`MIM ELECTROLYTIC CONDENSERS, SPEAKERS, CONNECTING WIRE, ctascifjed advertisements are CABLES, SCREENED WIRE, SCREWS, NUTS, CHOKES, TRANSFOR- 'p p' MERS, etc. genuine, but readers must satisfy `0386-832152si ALL AT KNOCKOUT PRICES - Come and pay us a visit ALADDIN'S CAVE themselves that they will be a obtaining what they require ' TELEPHONE: 445 0749/445 2713 before entering into transactions, HIM R. HENSON WilliemaP.C.B.ortwork, 40 Weatbourna LTD. particularly if they involve large 21 Lodge Lane, North Finchley, London, N.12 Hone bourne, hern, \Norce, (5 minutes from Tally Ho Corner) 11613) sums of money. -2,19

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www.americanradiohistory.com ITT Model 350 TELE FAX Facsimile transmitter/receiver. Microprocessor controlled (80851 CCITT Group 2 machine for transmitting documents over an ordinary phone line. BRAND NEW AND COMPUTER APPRECIATION BOXED £350.00 16 Walton Street, Oxford OX1 2HQ TEKTRONIX Model 4601 hard copy unit for 400 series graphicsterminals £95.00 Tel: Oxford (0865) 55163 Telex: 838750 TEKTRONIX Model 611 graphics storage display. For use with any DAC computer output. £150.00 IBM PERSONAL COMPUTER Model XT, with single floppy & 10MB Winchester AS FACIT Model 4020 high speed paper tape reader. Parallel TTL interface £225.00 NEW £2,700.00 FACIT Mode14070 PAPER TAPE PUNCH. BRAND NEW £350.00 UNITRON Model 2200 microcomputer. APPLE II/e & CP/M compatible machine with 6502 & Z80 CALCOMP Model 563 AO drum plotter. 0.1 mm step size £650.00 processors, 64kbyte memory, detached keyboard with numeric pad and floppy disc interface. CALCOMP Model 763 AO plotter. As above, but high speed P O A BRAND NEW & BOXED £350.00 CALCOMP Model 1036 AO graph plotter. High speed 3 colour plotter with Type 915 magnetic COMPAQ PLUS. IBM PC COMPATIBLE portable computer with 10MB hard disk, single floppy tape unit for optional off-line use,&selectable for 7/9 track, 800/1600 b.p. i. etc P.O.A. disc, 640k bytes, graphics, comprehensive software etc. AS NEW £2,900.00 C.I.L. Model 6000, 2 pen AO high speed graph plotter P.O.A. ROCKWELL AIM 65/40 single board 6502 development system with display, keyboard, power HEWLETT-PACKARD Model 75C portable computer £350.00 supply and cassette recorder £525.00 HEWLETT-PACKARDModel 85 desk top computer with integral graphics display, printer & tape PHILIPS P2000 SYSTEM comprising, 48K Z80 processor with integral tape drive, twin 51" floppy drive. Includes printer interface (82949A), ROM drawer (82936A). 16K expansion (82903A) & I/O disc drives, HONEYWELL Model L32120cps matrix printer. Runs CP/m £850.00 ROM (150031 £850.00 OLYMPIA BOSS MICROCOMPUTER, small Z80 based business system with 80 col. screen, 64k GOULD-BRYANS Model 50000 graph plotter. 380mm x 280mm plotting area with 0.1m resolu- byte memory, twin 51" floppy disc drives, HONEYWELL. Model L32 120cps matrix printer. Runs tion and vector plotting speed of 35cm/s. With intelligent controller providing 112 character set at CP/M £550.00 4 orientations RS 232 interface. NEW £985.00 MANNESMANN/TALLY Model M8OMC matrix printer. With microprocessor control, 200cps bidi- HEWLETT-PACKARD Model 41 C calculator with printer £125.00 rectional PRINTING WITH U/L case, self test. Compact but heavy duty machine. BRAND NEW & GENERAL DATACOMM (IAL) Model LDM-1 private line modem £150.00 BOXED £125.00 GENERAL DATACOM Model TDM 12404line statistical multiplexer as used with above modem. CENTRONICS Model 730-2 matrix printer £95.00 280 controlled. Manufactured 1981 £150.00 CENTRONICS Model 702 matrix printer, 132 col. 165cps, bidirectional printing with self test. In SONY U-matic video recorder with stereo sound £150.00 good ex -demo condition £225.00 DEC LSI-11 /23 processor with MMU £500.00 DEC boxes & power supplies. Various models available (BA11 MF, SB11 AA, BA11 LX) all with 22 bit Please note VAT & CARRIAGE extra on all Items Visitors by appointment. please.' Technical manuals are addressing or easily modified &variousoptionalprocessorsetc P.O.A. available from us for many items stocked. CIRCLE 92 FOR FURTHER DETAILS.

INDEX TO Wirelessa1d ADVERTISERS Appointments Vacant Advertisements appear on pages 92 - 103 PAGE PAGE PAGE AEL Crystals 4 Farnell Instruments Inside front cover Omnitest Ltd 24 Airlink Transformers 84 Field Electric Ltd 1 AM Electronics 84 Fylde Electronics 36 Pantechnic 88 Amplicon Electronics 55 Philips Personal Computers 4 Andelos Systems 42 Gemini Microcomputers 40/41 P.M. Components 22/23 Antex Ltd Inside back cover Gould Instruments 48 Pye Unicam 65 Armon Products Ltd 48 GNC Electronics 14 Aspen Electronics 14 Grandata Ltd 90 Automation & Control Tech 27 Greenwood Electronics 27 R. Henson Ltd 30 Radford Electronics 4 Barrie Electronics 90 Hameg Oscilloscopes 4 Radiocode Clocks 1 Beckenham Peripherals 24 Happy Memories 75 Raedek Electronics 77 Black Star Ltd 64 Harris Electronics 24 Research Communications 24 Branson, SJ. 74 Harrison Bros 48, 64 Bull, J. (Electrical) Ltd 88 Hart Electronics 91 Henrys/Audio Electronics 39 Service Trading Co 12 74 C&A Electronics 89 Hi -tech 15 S.J. Branson Cambridge Kits 64 HRS Electronics 89 Sherwood Data Systems 88 Cambridge Micro Processor 58 HW International 76 Special Products (Distributors) 40 76 Carston Electronics 14 Henson, R. Ltd 30 Stewart of Reading 64 CIL Electronics 56/57 Strumech Engineering Clark Masts Ltd 30 ILP Electronics 9, 35 Surrey Electronics 42 Computer Appreciation 104 IMS Electronics 53 Sowter, E.A. Ltd 76 Conguin Software back cover Industrial Auctions Ltd 90 83 Interface Quartz Devices Ltd 36 Cricklewood Electronics Taylor Bros 74 89 Irvine Business Systems 51 Crotech Instruments Technomatic Ltd 28/29 Cymbernetic Applications 9 Television 30 Keithley Instruments 21 Thandar Electronics 35, 75 5 Dataman Design Kemo Ltd 53 Thanet Electronics 51 Micro 48 Dedicated Processors Kimberry Ltd 30 Thorn EMI Datatech 58 84 Digitask Business Systems TK Electronics 74 86/87 Display Electronics Langrex Supplies 85 Triangle Digital Service 12 Time Electronics 91 EDA Software 53 42 Thurlby Electronics 16 Electronic Brokers 10/11, 13 Martin Associates Co 47 Electronic Equipment Company 9 Midwich Computer Monolith Electronics 14 Ellmax Electronics 27 Vigilant Communications Ltd 42 Electrovalue 40 Eltime Ltd 51 Newrad Instruments Case's 1 EMS Manufactures 75 Northern Amateur Radio Society Association 14 Waugh Instruments 84 Essex Electronics 64 Number One Systems 12 Withers Communication(R) 36

OVERSEAS ADVERTISEMENT AGENTS Japan: Mr Inatsuki, Trade Media - IBPA (Japan), B.212. Azabu Jack Mantel, The Farley Co., Suite 650, Ranna Building, France and Belgium: Pierre Mussard, 18 - 20 Place de la Heights, 1.5.10 Roppongi, Minalo-ku 106. Cleveland, Ohio 4415 - Telephone (216) 621 1919. Madeleine, Paris 75008. 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, 111 Eighth Avenue, New York, N.Y. 10011.

104 ELECTRONICS & WIRELESS WORLD MARCH 1985

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