I es órldJUNE 1985 85p KMAZINUAR CO 1-00.1. Switched-mode power supplies Improving BBC data recording Look after your nicad batteries Ot n; C D'a ; 24.00 www.americanradiohistory.com CONGUIN SOFTWARE Low Cost IBM PC Based CAD Systems smARTWORK AUTOCAD An Electronic LIGHT -BOX allowing layout of General 2D drafting package with auto - component pads with auto or interactive dimensioning. Will support a variety of tracking. Artwork can be printed on Epson graphic displays and output devices. dot matrix printer or plotted on Houston Software from £1000.00. Instrument or Hewlett Packard plotters. Systems from £3495.00. smARTWORK Software only £895.00. Complete systems from £3500.00. SAM 2001 - XT An IBM compatible with 10Mbyte hard disk, will run all IBM software. Can be upgraded to run as fast as an AT. CEDS From £1995.00. A full PCB design system allowing the design of boards from schematic diagrams. Note: All prices exclude VAT and are Systemm expandable from basic manual subject to change without notice. placing and routing to auto -tracking and schematic capture. Also available with Terms: Strictly CASH WITH ORDER. technical drawing facilities and auto dimensioning. Software from £1200.00. High resolution colour systems from £6000.00. PSPICE Circuit simulation package allowing simulation of upto 120 transistors with unlimited number of nodes. Performs AC, DC and transient analysis. Can us CEDS schematic capture as input. Software from £950.00. Conguin Software, Freepost, Lancaster LA1 1BR. Phone: 0524 381423 CIRCLE I F'ORFURTHERINFORMATION www.americanradiohistory.com Editor ELECTRONICS 8 PHILIP DARRINGTON Deputy Editor GEOFFREY SHORTER, B .Sc. 01- 6618639 ire Technical Editor wor MARTIN ese ECCLES over 70 years in independent electronics publishing 01- 6618638 Projects Editor June 1985 RICHARD LAMBLEY 01- 6613039 OR 8637 News Editor Volume 91 number 1592 DAVID SCOBIE 01- 6618632 Drawing Office ROGER GOODMAN Fast camera interface 17 Look after your nickel cadmium cells 60 01- 6618690 by Safa S. Omran by Rod Cooper Taking one pixel from each line of a video camera NiCd cells are expensive to buy yet are often BETTY PALMER signal to feed a micro is a solution to the speed thrown away for lack of a few drops of water. Rod problem. This method uses eight. Cooper discusses more failure modes and Advertisement Manager suggests how to avoid them. BOB NIBBS, A.C.I.I. 01- 6613130 Sampled -data servos new analysis -a 34 MICHAEL DOWNING by D.M. Taub Cassette recording with the BBC micro 01- 6618640 Fourth instalment in this new tutorial series by David Stonebanks 64 derives the response of a servo system to Improved performance with conventional ASHLEY WALLIS sinusoidal input. recorders and an alternative digital method. 01- 6618641 Northern Sales Managing research and development HARRY AIKEN Valve disc preamplifier by R.E. Young 061 -872 8861 In which the 'small -team' approach to R & D by Richard Brice 73 contrasts with the hierarchical style of Simple design without overall feedback, using Midland Sales management. passive RIAA equalization. BASIL McGOWAN 021 -356 4838 Helical antennas for 435 MHz by James Miller 43 Power'85 Classified Manager Simple -to -make design having true circular List of exhibitors 75 BRIAN DURRANT polarization. Intended for satellite working, but 01- 6613106 excellent also for local and long distance IAN FAUX operations. Two -dimensional digital filter design 01- 6613033 by R.N. Gorgui -Naguib, K.M. Henein and 76 Switched -mode power supplies 49 R.A. King Production by K.L. Smith Thik detailed comparison of current design BRIAN BANNISTER This part of the d.c. supplies series explains the techniques follows the authors' earlier article on (Make-up and copy) theory, practice and design of switchers. one-dimensional filters. 01- 6618648 Reactivating Band Ili 57 Channel code and disc format 80 Current issue price 85p, back issues (if A report from the Mobile Radio Users' by John Watkinson available) £ 1.06, at Retail and Trade Association conference which discussed trunked Part of our definitive Compact Disc series, this Counter, Units 1 & 2, Bankside Industrial repeater networks and worsening interference continuation shows how the information is Centre, Hopton Street, London SE 1. Available on microfilm; please contact problems. organised on the disc surface. editor. By post, current issue £ 1.30, back issues (if available) £1.40, order and payments to EEP Sundry Sales Dept., Quadrant House, REGULARS The Quadrant, Sutton, Surrey SM2 5AS. Tel.: 01- 6613378. Editorial & Advertising offices: News Commentary 6 Circuit ideas 29 Wirelesswörld Quadrant House, The Quadrant, Sutton, New blood Trip for power switches Surrey SM2 5AD. End of ATS -1 Two -i.c. shortwave calibrator Telephones: Editorial 01- 6613614. Advertising 01- 6613130. See leader page. Towards a thinking computer Fast converter for repetitive signals Telex: 892084 BISPRS G (EEP) Sending text to Wireless World ' Centronics -to -RS232 converter Subscription rates: 1 year £ 15 UK and Coming to this screen shortly... , £21 outside UK. Student rates: 1 year £ 10 UK and £ 14 outside UK. 69 °`Feedback, Distribution: Quadrant House, The Books D.c. supplies .... Quadrant, Sutton, Surrey SM2 5AS. 20 Telephone 01- 6613248. Electro reductionism Subscriptions: Oakfield House, Relativity Perrymount Road, Haywards Heath, Energy transfer Sussex RH16 3DH. telephone: 04444 coter shows the 70cm 459188. Please notify a change of Communications 23 Front address. aerial ma de by James Miller for USA: S102.70 airmail. Business Press Costly DEF the RSGB's headquarters International (USA). Subscriptions Office, V.h.f. changes New Products 84 205 E. 42nd Street, NY 10017. Radar up -date Fast tape storage station at Potters Bar. USA mailing agents: Expediters of the JAS -1 in 1986 256K s.ram Photography by Grahame Printed World Ltd, 527 Madison Avénue, Circuit diagrams on a micro Richardson. Suite 1217, New York, NY 10022, 2nd class postage paid at New York. © Business Press International Ltd 1983. ISBN 0043 6062. www.americanradiohistory.com i ' Comes in a 16K EPROM and 40tk disc for the BBC EI o Complete Wordwise style integrated A editor with special debugging aids Assembles for 7 different MPU families .. right now - FREE updates take this up to 11 -"' ETA Nestable Macros (with parameters), ' ASSEMBLER Nestable IF /ELSE /ENDIF conditional assembly Specially integrated Macro Library facilities fully is both an Editor and a very special Assembler. Macros and IF /ELSE /ENDIF Conditional Assembly are META Meta can Assemble all these 16K EPROM, but the tables supported, and both are nestable. Macros may also pass Most of META resides on a instruction sets right now: defining the language the Assembler is to translate Assembler parameters, and contain local labels. There's also a range of for ANY instruction set - you specify which you want to use EQU pseudo -ops for data setup, all of which may have a list 65xx series incl. cmos can also in your source code. of arguments seperated by a comma. Disc datafiles The large box on the right details all the instruction sets be inserted into the object code. A complex integrated Macro 68xx /63xx series incl. that have been coded for META right now: all these are Library system is also included - you can invoke a routine 00,01,02,03,05 supplied free with META. The other 4 instruction sets will be and pass parameters by just giving its name. in fast (we 6809 65816 supplied as soon as they are written and tested as A FREE Source code is Assembled two passes don't ... inferior UPGRADE. Were on Freepost, so you won't even have to use the groaning slow BPUT & BGET as do some 8048 series pay postage. Assemblers. Instead portions of the source code are META contains a fully integrated Editor. This follows effectively *LOADed in at top speed.) The resultant object 8080/8085 RAM, user or Wordwise as closely as possible in its philosophy (ie cursor code may be sent to disc files, sideways the down Z8 keys used to move text - quickly - up and down about printer port (full details and examples in manual), or central editing line etc), and includes Global /Selective Search/ the RS423. META Z80 Replace, Markers (copy,save,delete, find marked text), load Remember that all instructions sets supported by the Library etc) text to cursor, character count and heaps of other features. have access to all the above features (Macros, And Free updates ('Real manual and If an error is detected during assembly, the Editor is right META comes complete with a comprehensive Soon Now') include: BBC game there: on the bad line with a plain English error message function key strip. 16K of source code for a 6502 describing the fault. is included free and the META system disc, which 68000 8088/8086 well Complex expressions are allowed by the Assembler, demonstrates many of the features of this assembler. (as Z8000 Micro Nova including brackets to 8 levels (!). All calculations are to 32 as being a neat game!) bits. CRASH BARRIER FREEPOST METNA55EMBLER £69'9s FLITWICK All inclusive. Free updates included in price - BEDFORD updates expected to be available early July. META is available right now. MK 45 1YP Dealer enquiries, as the saying goes, are welcome. (0525) 717148 Generous discounts to educational institutions. CIRCLE 83 FOR FURTHER DETAILS. COMPUTER APPRECIATION 16 Walton Street, Oxford OX1 2HQ Tel: Oxford (0865) 55163 Telex: 838750 £50.00 UNITRON Model 2200 Microcomputer, Apple 11/E and CP /M compatible machine with 6502 and TEKTRONIXModel4601 harda copy unit for 400 series graphic terminals computer output £75.00 Z80 processors, 64 Kbyte memory, detached keyboard with numeric pad and floppy disc TEKTRONIX Model 611 Graphics storage display. For use with any DAC £225.00 interface. BRAND NEW AND BOXED £325.00 FACh Model 4020 High speed paperand tape reader.