Magnetostrictive delay-line stores and some logical applications

Four types of magnetostrictive delay-line stores, two of which have delay of 100 microsec and the others 900 microsec, are used in the Highgate Wood electronic telephone exchange to perform storage and logical functions. These stores were developed separately for use in three sections of the exchange. Techniques employed in the design of these stores include the use of thermionic valves and transistors. One type of store operates at a frequency of 1 Mc/s and the others at 500 kc/s. The reasons for the choice of a magnetostrictive delay-line store and of the materials used are given. The first half of the paper deals with the design and construction of the stores and with practical problems. The second half deals with some typical applications, including storage, counting, subtraction, persistence checking, timing and pulse exchange.