GB562728A - Stable electric-oscillation generator and angular-velocity modulator - Google Patents

Abstract

562,728. Valve generating and modulating circuits. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. March 26, 1943, No. 4939. Convention date, March 27, 1942. [Class 40 (v)] An oscillation generator and angular-velocity modulator includes a source of stabilized oscillations of frequency Fs coupled to both first and second heterodyne converters, the output of the first converter is coupled to the input of the second converter by a coupling tuned to a frequency f and associated with a modulating means and the output of the second converter is coupled to the input of the first converter so that self-sustained oscillations are generated and modulated in angular velocity. The Figure shows two grid frequency changer valves 10, 40 fed from a source 50 and coupled by a circuit 26 tuned to frequency f and by condenser 49. Modulation is applied in pushpull to valves 60, 80 acting respectively as a capacitative and an inductive reactance and serving to vary the frequency of the circuit 26, thus modulating the signal produced by the self-sustaining oscillations. In a modification, Fig. 2 (not shown), pairs of frequency changers in cascade are used, connected in parallel channels and all fed in parallel from the source of stabilized oscillations. In one channel the coupling is tuned slightly above and in the other slightly below the frequency f and the modulated potentials are applied in push-pull to the two channels, while the output is taken from the two channels in parallel.