GB595200A - Stabilised harmonic electronic oscillator - Google Patents

Abstract

595,200. Valve generating circuits. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Jan. 16, 1945, No. 1358. Convention date, May 15, 1943. [Class 40 (v)] In a frequency multiplying circuit a gasfilled valve generates pulses under the control of a fundamental frequency, the pulses being applied to synchronize an oscillator operating at a harmonic frequency, the gas-filled valve being extinguished after an interval less than the half period of the harmonic frequency. The fundamental frequency, applied to the grid of gas-filled valve 1 causes it to fire to generate a positive pulse on the cathode, the pulse being terminated when capacitor 11 discharges to the ionizing potential of valve 1. The positive pulse is applied over a blocking condenser to the screen grid of the oscillator valve 12, the associated circuit 21, 22 being tuned to a harmonic of the fundamental frequency. The cathode of valve 1 is positively biassed over resistors 7a, 27 and the recharging time of capacitor 11 may be varied by adjusting resistor 5. In a modification, Fig. 3 (not shown), the pulse from valve 1 is applied to the grid of valve 12, the tuned circuit being coupled to the screen grid over a capacitor shunted by a resistor. The oscillator stage 12 may comprise two valves in push-pull and the pulse excitation may be derived from the anode circuit of valve 1 and applied to the cathode circuit of the oscillator. Alternatively, the pulse may be generated across an impedance in series with capacitor 11.