GB698950A - Electrical pulse shaping circuits - Google Patents

Abstract

698,950. Pulse shaping circuits. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Nov. 23, 1951 [Nov. 23, 1950], No. 28653/50. Class 40 (vi). A pulse-shaping circuit comprises a device to which periodically recurring input pulses are applied which are of such an amplitude that the state of conductivity of the elements of the device changes twice during the incidence of one of the pulses, the output pulses being maintained of constant duration by means of an integrating circuit which is fed with an output from the device and feeds a bias voltage back to its input. Fig. 1 shows a pulse-shaping circuit in which pulses from a source S such as shown at (a) in Fig. 2 are applied via a phaseshifting network T to a valve V1 so that at a level such as shown at (b) in Fig. 2 the valve conducts and at a further level (c) is passing maximum cathode current. Thus an output is obtained from valve V1 as shown at (d) in Fig. 2, part of this is integrated in capacitor C2 and is applied as a bias to the grid circuit of valve V1 to maintain the mean current through the valve substantially constant. The ratio t/T of the pulses shown in Fig. 2 is given by I/n which is equal to that fraction of the total current through resistor R4 which passes through valve V1 when no input is applied to it. The output pulses are thus of constant duration. The pulses to be shaped may be substantially sinusoidal so that when fed through a phase-shifter T the timing of the output pulses may be controlled.