摘要:

The paper describes the principles of operation and the construction of storage units with a very short access time for reading. One form of the store which has been constructed has a capacity of 200 000 bits of permanent information and another has been built with a capacity of 100 000 bits, the whole contents of which may be changed in under one minute. The technique employed permits the construction of very large stores at low cost. Each digit cell is formed, basically, by two sets of windings which form the primary and secondary of a transformer and the two binary states are determined by the presence or absence of a piece of linear ferrite material coupling the windings. The access time is largely determined by the physical size of the store and the speed of operation of the associated circuits; a time of 100 millimicrosec is typical.

DOI:10.1049/pi-b-2.1960.0170

出版商:IEE    

年代:1960

数据来源: IET

摘要:

The paper describes a transistor switch technique which is of particular importance in applications where a large number of switches have to be connected in series and where the propagation time of information through these switches has to be a minimum. It is thus of importance in parallel addition, and its use in this connection has been successfully demonstrated, yielding an addition time over 24 digits of 200 millimicrosec. The technique is reasonably economical, and the paper also shows how it can be used in conjunction with more conventional logical circuits to provide a simple arithmetic unit.

DOI:10.1049/pi-b-2.1960.0171

出版商:IEE    

年代:1960

数据来源: IET

摘要:

Improvements in storage systems using currently available square-loop ferrite cores are considered. These enable the normal cycle time of 6–10 microsec to be reduced to less than 2 microsec. Effort has been concentrated on the word-selected two-core-per-digit arrangement, and the most promising techniques are those which involve partial-flux switching. A system is developed suitable for a store of 1024 words of 52 digits with a cycle time of about 1.6 microsec. In a smaller store of, say, 100 words, a cycle time of approximately 0.6 microsec is feasible.

DOI:10.1049/pi-b-2.1960.0172

出版商:IEE    

年代:1960

数据来源: IET

摘要:

The possibility that a matrix of electroluminescent cells could be used for storage of information in digital form has long been realized. The problems involved in reading information from a simple type of permanent store are discussed. It has been shown that the read-out time is limited by the afterglow of the phosphor, and, for a particular (ZnS, Cu, Cl) phosphor, it is 25–30 microsec per digit. A theoretical calculation of the discrimination ratio, i.e. the ratio of the output signal from a ‘1’ to the interference signal obtained when a ‘0’ is selected, shows that it should be possible to operate matrices with as many as 642cells. This conclusion is not borne out by measurements made on experimental panels; these suggest that 322is about the maximum. Results obtained in the paper are regarded as preliminary since arbitrary choices have had to be made concerning some aspects of the operation of the matrices. There is little doubt that considerable improvement in performance is possible.

DOI:10.1049/pi-b-2.1960.0173

出版商:IEE    

年代:1960

数据来源: IET

摘要:

The paper shows the need for a selection and testing machine in the light of recent developments in the automatic assembly of components on to printed-wiring boards. The advantages of a programmed machine are given and the flexibility and simplicity obtained are illustrated.The general operation of the machine is outlined. Examples of the method of coding and the technique of programming on to punched-paper tape are included. The build-up of the electronic control from a number of relatively simple basic circuits is shown.Finally, the range of components handled, details of the test bridges, and the overall speed and reliability are given.

DOI:10.1049/pi-b-2.1960.0176

出版商:IEE    

年代:1960

数据来源: IET

摘要:

Techniques at present in use for the recording of single-shot phenomena by cathode-ray oscillographs are reviewed. Cathode-ray tubes are discussed, with particular attention to the conflicting requirements of high writing speed, wide bandwidth and high sensitivity. These requirements can be met to a large extent by the use of very small spot size and travelling-wave techniques. An account is given also of associated circuits including high-speed time-bases, amplifiers and calibration equipment.

DOI:10.1049/pi-b-2.1960.0177

出版商:IEE    

年代:1960

数据来源: IET

摘要:

The paper describes a new measuring system, using 100 line/in optical gratings, which contains no moving parts and has been incorporated in both continuous-path and co-ordinate-setting control systems.By a method of cyclic switching of four photocells and subsequent filtering of the combined photocell signals, an a.c. waveform is produced which can be compared in phase with a reference waveform, to determine the magnitude and direction of relative displacement between two gratings, and to provide linear interpolation within the pitch of the gratings.Details of the optical, mechanical and electronic design are given, and the effects of variables on the accuracy of the system are discussed.Interpolation accuracy within ±2 × 10−4in using 100 lines/in gratings has been achieved in practical systems.

DOI:10.1049/pi-b-2.1960.0178

出版商:IEE    

年代:1960

数据来源: IET