Patent GB-842389-A (GB)
Title: A memory system for an electric signal
Inventor: MUROGA SABURO
IPC: G11C11/20
Filed: 1956-08-31
Abstract: 842,389. Circuits employing bi-stable magnetic elements. NIPPON TELEGRAPH & TELEPHONE PUBLIC CORPORATION. Aug. 31, 1956, No. 26679/56. Class 40 (9). [Also in Group XIX] A magnetic or dielectric memory matrix has selected storage elements set to remanent states representing binary zero or binary one by coincident alternating currents applied to column and row conductors, the remanent state of each element being determined by the relative phase position O or # of the column current. As shown in Fig. 1, signals from a controlling circuit 4 cause equipment 5 to transmit a binary word to a register 1 which translates each digit into a high-frequency alternating current having a relative phase of O or #, Fig. 2a and 2b, depending on whether the digit is zero or one respectively. The binary word is then applied to the memory column conductors 11-16, and a word line in the matrix is selected by a controlling signal passed from 4 to a selective circuit 2 which applies an alternating signal of the waveform shown in Fig. 2 c to a row conductor 21- 26. This alternating signal comprises a lowfrequency alternating current of rectangular waveform modulated by high-frequency currents having the same frequency and amplitude as the current in the column conductors, the positive half cycles being modulated by zerophase high frequency, Fig. 2 a, while the negative half cycles are modulated by #-phase high frequency, Fig. 2 b. In consequence, a resultant signal having a waveform shown in Fig. 2 d or Fig. 2 e is produced at each of the memory elements subjected to coincident signals. If the appropriate column lead is energized by a binary zero signal then a resultant with high positive peaks, Fig. 2 d, is produced, while high negative peaks, Fig. 2 e, are peculiar to a binary one. These peaks have sufficient amplitude to overcome the coercivity of those storage elements in the opposite stable state of remanence to the binary registration required, and drive the elements so as to effect the appropriate word registration. To read-out the recorded information, a row conductor is re-energized by current having the Fig. 2 c waveform. If an interrogated magnetic core is in the binary zero state, then positive half cycles of row conductor current will only drive it further into saturation, but negative half cycles will tend to reverse its stable state and so permit a high-frequency output current of zero phase to be induced in the associated row conductor. Similarly positive half cycles produce a #-phase output when the core is in the binary one state. The spurious read-out signals which occur during the half cycles when the core is driven further into saturation are neutralized by an opposing high frequency of slightly larger amplitude, this frequency being applied by the selective circuit 2 to the register over lead 10 with relative phases of # and zero during respective positive and negative half cycles of the modulated row current. It is stated that interrogation does not destroy the recorded information since the induced currents in the column windings have the effect in the next half cycle of restoring the core to its original remanent state, and that zero and phase high-frequency signals may be provided by parametrically excited oscillators. An alternative arrangement of matrix conductors is also described, Fig. 4 (not shown).