Patent GB-914697-A (GB)
Title: Magnetic storage systems
IPC: G11C8/00
Filed: 1960-07-22
Abstract: 914,697. Magnetic storage devices. STANDARD TELEPHONES & CABLES Ltd. July 22, 1960 [July 24, 1959], No. 25623/60. Class 38 (2). [Also in Groups XIX and XXXIX] Binary information in the form of positive and negative electrical pulses is registered in discrete regions of a core 4, Fig. 1, having remanent properties by propagating a mechanical pulse along a magnetostrictive element 2, the electrical pulses being applied sequentially to a winding 8 on a non-remanent magnetic yoke 7 during the time period that the mechanical pulse exists between the extremities of the yoke and core. A further mechanical pulse in the magnetostrictive element then effects non-destructive read-out of the stored information by causing induced pulses in the winding 8 the polarities of which depend on the directions of magnetization of the discrete regions. The magnetostrictive element is formed of annealed nickel and is supported by rubber units 6 which prevent pulse reflection. Steel wool 17a is packed between the yoke extremities and the magnetostrictive element. An electrical pulse from a control signal source 5 is applied to a coil 3 to produce a mechanical pulse; alternatively a piezoelectric transducer may be used. As the mechanical pulse travels along the magnetostrictive element, gate 10 is opened to permit the sequential application of positive and negative pulses, representing binary one and binary zero, respectively, to winding 8. Corresponding flux pulses in one or other direction are produced in the yoke 7 and in the portion of the magnetostrictive element between the yoke extremities. The mechanical pulse 2a, Fig. 2, has the property of increasing the reluctance of the element 2 over the region where the pulse exists. Consequentially a flux pulse is diverted into a discrete region of the core (4a, as shown) at the position where the mechanical pulse exists at that time. Thus, as the mechanical pulse moves along the element 2 and serial input pulses are applied to winding 8, a series of characteristic remanent states in regions 4a to 4e are set up in the core 4. Non-destructive read-out is effected by transmitting a mechanical pulse and opening gate 11 at the same time to connect winding 8 to a read circuit 13. As the mechanical pulse passes a region 4a to 4e the localized flux through the element 2 is diverted through the yoke 7 and pulses are induced in winding 8 the polarities of which are characteristic of the remanent states. The core may be cleared by applying a magnetic bias or by reading in a series of binary zero signals. Fig. 4 illustrates an arrangement for storing information in a plurality of stores 23 to 26 each as shown in Fig. 1. For reading or writing, a signal from respective control circuits 19 and 20 is applied over an amplifier 22 to coils 27 to 30 to produce coincident mechanical pulses in the magnetostrictive elements. To write a binary word transmitted from a write amplifier 17 at any particular position of the mechanical pulses, gates 31 to 34 are opened by control signals from control circuit 20 to complete circuits to yoke windings 47 to 50. To read one or more stores at any particular position of the mechanical pulses, gates 35 to 38 are opened to connect the yoke windings to read amplifiers 21.