Theory of Magnetostrictive Delay Lines for Pulse and Continuous Wave Transmission

Developments in the Logical Organization of Computer Arithmetic and Control Units

http://ieeexplore.ieee.org/iel5/10324/32761/01538238.pdf

A Theory of Pulse Transmission Along a Magnetostrictive Delay Line

The paper describes two magnetostrictive delay-line stores which have been developed for use in data processing. The use of transistors has enabled the stores to be constructed in the form of compact plug-in units using printed wiring. One delay line has a delay time of 100 microsec and the other has a delay of 1 millisec. Both use a repetition rate of 1 Mc/s. They therefore store 100 and 1000 binary digits, respectively. The lines use Permendur wire to transmit a longitudinal stress wave. The 1 millisec line has a temperature-compensating device which adjusts the distance between the transducer coils in order to keep the delay time-constant to within ±0.1 microsec over a temperature range of 20°C. The recirculation path of the store is provided by a transistor circuit. The small output signal from the receiving coil of the line is amplified by multi-stage negative-feedback amplifier. Output pulses from the amplifier are shaped by a transistor clipping stage and then lengthened by a novel circuit utilizing the hole-storage effect. The output of the pulse lengthener is gated by clock pulses. This arrangement permits the delay time of the line to vary by 0.6 microsec without affecting the timing of the gated pulses. These pulses are lengthened by a further hole-storage circuit and they supply an output to external circuits via an emitter-follower. The output pulses are of 8 volts amplitude and have rise and fall times of 60 millimicrosec. The output pulses are also fed via `write? and `erase? gates to the transistor amplifier which drives the sending coil of the line. A companion paper describes circuits for performing logical operations in association with these delay-line stores.

Magnetostrictive delay-line stores operating at 1 Mc/s using transistor circuits

Earlier papers have described transistor circuits for use as computer elements. This paper describes the development of these, and various gating circuits, as the standard elements from which a digital computer has been constructed. The application of the standard circuits to the arithmetic unit of the computer is illustrated by two examples: an adder of unusual logical design to suit the interleaved-word storage system, and a multiplier system which forms the signed product of two 31-digit binary words in six word-times. A general description of the computer, and details of the magnetic-drum store, are given in accompanying papers.

Transistor arithmetic circuits for an interleaved-digit computer

The transistor is gradually establishing itself as a useful circuit element, but although individual circuits have proved to be adequately reliable their collective reliability in a more complex apparatus has not hitherto been proved. Accordingly a digital fast multiplier?an important part of any large-scale computer?has been constructed using transistors throughout. Operating at a basic frequency of 125kc/s, the multiplier computes the product of two 32-digit serial numbers in about 4 millisec. The logical design has a novel feature in that the digits of the multiplier are taken in pairs instead of singly. The multiplier can be divided into three parts: the generator of timing waveforms, the arithmetic unit and the storage system. Point-contact transistors are used throughout except in the amplifiers associated with the storage system, where junction units are used. The actual storage elements are magnetostrictive delay lines; some of the results of an investigation into their operation are included as appendices. Out of a total of 84 point-contact transistors, 12 junction transistors and 568 crystal diodes, 3 point-contact units have failed in 7 months of daily operation. No selection of transistors is required. The total power consumption is 50 watts. It is concluded that transistors of the types at present available are well suited to computer circuits and that both the construction and maintenance of the apparatus are facilitated by their use.

https://ieeexplore.ieee.org/iel5/5242809/5242945/05243152.pdf

R.E. Hayes

Papers

A transistor digital fast multiplier with magnetostrictive storage