Patent GB-916234-A (GB)
Title: Electric circuits comprising memory elements
IPC: B26B21/40
Filed: 1959-07-22
Abstract: 916,234. Circuits employing bi-stable magnetic elements. WESTERN ELECTRIC CO. Inc. July 22, 1959 [Aug. 4, 1958], No. 25088/59. Class 40 (9). [Also in Group XIX] A shift register or delay line comprises a conductor 20, Fig. 1, having a magnetically preferred helical flux path along its axis, or a ferro-electric slab 90, Fig. 2, binary information being registered along the conductor or slab by the stable polarization state of discrete portions of the material such as A, B and C in Fig. 1. Each portion is divided up by pairs of coils or electrodes into a number of segments, and each segment is sufficiently small as to be unable to remain in a stable state to which it is set if the segments on both sides are in the opposite stable state. Two or more adjacent segments in the same state, however, have a sufficient overall dimension to sustain a stable polarization. Initially, all the segments throughout the conductor or slab are in the same " 0 " remanent state, and information from an input pulse source 69 is applied to a first portion (A in Fig. 1) comprising the first three segments. If the input pulse represents a binary " I," the remanent state of the first portion is brought to a corresponding stable condition. The registered information is then stepped along the conductor or slab by the application of stepped advancing pulses # 1  to # 5 . The first advance pulse # 1  restores the first segment to a stable " 0 " state, and switches the fourth segment to state " 1 " which is stable as the adjacent second and third segments are in this state. The portion of the conductor or slab registering the input information then comprises segments two, three and four. Likewise the second advance pulse # 2  restores the second segment to stable state " 0 " and switches the fifth segment to stable state " 1," and so on for pulses # 3  to # 5 . When the input information reaches the last three segments (portion C in Fig. 1), lead-out is effected by a pulse which restores all three segments to state " 0." The arrangement shown in Fig. 1 uses either a ferro-magnetic conductor or a conductor wound with a ferro-magnetic wire or tape, and provides a helical flux path as described in Specification 877,731. The input pulses are applied to windings 66, 67 and 68 which are paired with advance windings 21, 22 and 23 respectively to define the first three segments. Similar advance winding pairs such as 24, 31 and 55, 63 define the remaining segments of the conductor, each winding of a pair having the opposite switching effect to its partner. All the advance windings are connected to selected phases of an advance pulse source 65 whereby the advance pulses # to # 5  shift the information along the conductor as previously described. Read-out is effected by energizing windings 70, 71, 72 simultaneously from a source 73, and if the portion C is in state " 1 " a voltage is induced between the ends of conductor 20 which is detected by an output circuit 76. Non-destructive read-out when information is in position B is also possible, an auxiliary readout source 75 being connected to a single winding 74 which when energized drives the associated segment partially to state "0." The alternative embodiment, Fig. 2, using a ferro-electric slab is basically similar, but in this case each advance pulse appears, on two wires as positive and negative components respectively. This feature is necessary so that two capacitors in series, such as 91 and 94 which define the first, and fourth segments respectively, may have their respective stable states changed in opposite senses. The various capacitors 91-103 are decoupled by resistors 115-127, 105-107 and 109-111, and the output voltage is read across resistor 112 by a circuit 114.