GB644899A - Improvements in or relating to impulse oscillation generators - Google Patents

Abstract

644,899. Pulse generating circuits. COMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL. Jan. 14, 1948, No. 1192. Convention date, Feb. 24, 1947. [Class 40 (vi)] In a relaxation oscillator comprising a thyratron valve the pulse repetition frequency is maintained constant by means of a delay line the delay of which determines the interval between the pulses. The Figure shows a pulse generator in which upon the discharge of capacitor C through the thyratron Th a positive pulse produced across resistor Z passes down the delay line L and triggers the thyratron to discharge capacitor C which has been charged in the interval via resistor R. The delay line is terminated at each end in its characteristic impedance. In a modification, Fig. 2 (not shown), the delay line is connected with one end in the grid circuit of the thyratron and the other end short-circuited, so that a negative pulse propogated down the line is reflected as a positive pulse to trigger the thyratron. The interval between pulses is thus equal to twice the one-way delay of the line. In a further modification, Fig. 3 (not shown), a transformer is connected between the anode and control grid of the thyratron, and the delay line, which is opencircuited at the distant end, is connected in parallel with the anode winding of the transformer. The interval between successive pulses is equal to twice the one way delay of the line. The oscillator may be synchronized by applying the synchronizing signal to a second control grid of the thyratron.