GB589606A - Improvements in or relating to pulse-operated thermionic valve circuits - Google Patents

Abstract

589,606. Pulse generating circuits. REID, D. G., and CHADWICK, C. C. July 20, 1944, No. 13951. [Class 40 (v)] In a circuit for converting irregular pulses into regular pulses, a single pulse converting valve is triggered into an operative condition by the leading edge of an input pulse, which is also fed over a delay line and separate channel to trigger the valve back to its initial condition. The intermediate electrodes of the valve may be coupled by a resistance capacity combination having a time-constant considerably greater than the length of the required pulses. The anode of diode V3a is biassed a few volts negative while lower end of resistance R2 is connected to a large negative bias potential, the suppressor grid of valve V1 being held sufficiently negative to cut off the anode current. Upon receipt of a positive pulse over coupling condenser C1 diode V3b conducts, carrying the suppressor grid sufficiently more positive for anode current to flow, the screen current thereby falling and potential rising. This rise is transmitted over coupling condenser C2, the suppressor grid potential rising until it is held near earth potential due to diode V4a conducting. The pulse passes down a delay line DN to a phase-reversing valve V2 feeding over coupling condenser C6 an amplified negative pulse through diode V4b to the suppressor grid of valve V1 to restore the valve to its initial condition. The output pulse is taken from the anode of valve VI and diodes V5 a, b are included for D.C. restoration. Valve V2 may be replaced by a transformer. For producing shorter pulses, condenserresistance combinations C1, R1 and C6, R8 may be arranged to differentiate the controlling pulse. When the controlling pulse is negative, valve V1 is normally conducting, resistance R2 being connected to a positive potential, the direct pulse being applied over diode V4b and the delayed pulse over diode V3b.