Patent GB-1109004-A (GB)
Title: Parametric computers
IPC: G11C19/12
Filed: 1965-06-25
Abstract: 1,109,004. Parametron stores. INTERNATIONAL BUSINESS MACHINES CORPORATION. 25 June, 1965 [1 July, 1964], No. 26937/65. Heading G4C. [Also in Division H3] A parametric oscillator or parametron which resonates at the frequency of an input signal and is pumped by a higher frequency, e.g. twice the signal frequency, has its stable phase of operation, O or # radians, as established by the phase of the input signal, reversed at intervals by a disturbance of the pumping signal, this disturbance involving a change of pumping signal phase either with or without a reduction of amplitude or interruption of the pumping signal. Thus in a single parametron which is set into a particular stable phase relation by an input signal, the stable phase of the oscillation is reversed, e.g. O to # radians, or # to 2# radians, with each disturbance of the pumping signal. For binary storage a given sequence of phase changes, e.g. the sequence O, #, 2#, 3# radians, denotes a binary zero, while a similar sequence in the same time positions but displaced by # or - #, e.g. the sequence - #, O, #, 2# denotes a binary one. A change from one phase sequence to the other is effected by an input signal of appropriate phase when the pumping signal is disturbed. No change of phase sequence takes place if the input signal is either in phase or in antiphase with the exciting parametron oscillation. A basic arrangement is shown in Fig. 4 in which a parametron 21 has three inputs 21a, 21b, 21c and performs a majority-type logic operation in terms of the stable phase relationships, O or # radians, of the three inputs. This oscillator is pumped directly from a second harmonic pumping source 22. A further parametron 20 used as a memory oscillator is provided, this parametron being connected to the pumping source 22 and to parametron 21 by respective delay lines 23, 24, each introducing a delay of one-eighth of the signal frequency (one-quarter of the pumping frequency). When the pumping signal is disturbed by a substantial change of phase, receipt of this disturbance at parametron 20 causes it to establish a phase sequence characteristic of the phase of a signal source 21a. This phase sequence, delayed by 24, acts in conjunction with inputs 21a, 21b to determine the phase sequence of parametron 21 when the pumping signal is next disturbed. Due to the operational delays between parametrons 20, 21 caused by the delay lines, any phase sequence passed back from parametron 21 to parametron 20 is either in a O or # radian relationship with the oscillations of parametron 20 and so is without effect when the next pumping signal disturbance reaches this parametron. For low frequency operation using several parametron stages, a four-phase pumping source 22<SP>1</SP> may be used instead of delay lines 23. An extension of the Fig. 4 arrangement is used to form a shift register, Figs. 5a, 5b, 5c, the output parametron 27 being connected directly to the pumping source 30, and the parametron stages between the output 27b and the input 25a being connected in series with one-eighth signal cycle pumping and signal delay lines 29, 32, 28, 34. The graphs show how a previously established binary one phase sequence 40 in parametron 25 is extended to the phase sequence 45 of parametron 26 when a pumping disturbance takes place at time t 1 , parametrons 26 and 27 both being initially in the binary zero phase sequence state. Similarly at time t 2  the phase sequence 50 of parametron 27 is brought to the same state as that of the preceding stages. In this arrangement the pumping disturbance is an instantaneous reversal of phase as shown at 43, 48 and 53. Other pumping characteristics are described including phase reversal after a period of pump signal interruption, Fig. 8 (not shown) and a complex signal in which similar characteristics are obtained by combining two adjacent frequencies, Fig. 9 (not shown).