Improvements in or relating to information storage systems

1,094,311. Controlled non-linear inductors; transistor circuits. ELLIOTT BROS (LONDON) Ltd. Dec. 31, 1964 [Jan. 6, 1964], No. 596/64. Headings H3B and H3T. The output signal obtained from a transfluxor when it is interrogated is delayed and then compared with an input signal representing the information required to be stored within the transfluxor to derive an error signal which is applied to the input winding of the transfluxor to modify the flux pattern stored therein such that the output signal becomes equal to the input signal. The transfluxor 1 is first blocked by passing a blocking pulse through input winding 7 to saturate the transfluxor in an anti-clockwise direction and then an analogue signal is applied to input terminal 25, switch 29 being opened, to set the transfluxor. During the next cycle of the 10 kc/s.s supply from multivibrator 18, Fig. 4, diode switch 28 is opened and switch 17 closed to enable an interrogation signal to be applied to interrogate winding 8. The alternating output signal produced in winding 8 is rectified by phase-sensitive demodulator 19, Figs. 7, 21 (not shown), controlled by the output of multivibrator 18, and passed to a delaying amplifier 20, Figs. 8 (not shown), and 9, wherein the output is delayed before being passed to output 21 and via feedback loop 22 to a differential amplifier unit 24, Figs. 9, 10. During the next cycle of the 10 kc/s. supply from the multivibrator switch 28 is closed and switch 17, Fig. 11 (not shown), opened so that an error signal proportional to the difference in amplitude of the analogue input signal and the output of the amplifier is supplied to input winding 7 to change the flux pattern in the transfluxor so that the output of the amplifier becomes more nearly equal in amplitude to the analogue signal. When this is achieved after successive cycles switch 29 is closed and the input signal removed. Circuitry.-Multivibrator 18, Fig. 4, provides two 10 kc/s. pulse trains phase displaced by 180 degrees relatively to each other to output terminals 37, 38 connected to demodulator 19. One of the trains is amplified by amplifier 39 to provide an output to energize the interrogate winding 8 through diode switching circuit 16, Fig. 3 and Figs. 5, 6 (not shown), controlled by two 5 kc/s. trains of opposite polarity pulses from bi-stable circuit 31 and amplified by 41. The delaying amplifier 20, Fig. 8, comprises a two input direct voltage amplifier 63 (also Fig. 9, not shown), connected to a common