GB358145A - Improvements in ultra high frequency electronic oscillators - Google Patents

Abstract

358,145. Valve generating, modulating, and amplifying circuits. HOLLMANN, H. E., 54, Berliner Strasse, Charlottenburg, Berlin. July 10, 1930, No. 20946. Convention date, July 10, 1929. [Class 40 (v).] Relates to ultra-short wave oscillators of the kind in which the wave frequency is dependent on the speed of electronic oscillations within the valve, and consists in the inclusion in the plate circuit of an oscillatory circuit tuned to a comparatively low or audio frequency, which circuit is maintained in oscillation owing to a negative-resistance characteristic of the plate circuit, and serves to modulate the generated wave. The valve has its grid g maintained positive by a battery Eg, and its plate a slightly negative by a potentiometer p. The parallel wires connected to plate and grid are bridged by a condenser C connected between the halves l<1> of an aerial or radiator. The oscillatory circuit o is connected in the plate circuit beyond the chokes d<1> which exclude the short waves from the circuit o and the batteries &c. By suitable adjustment of the length d of the wires l, the plate circuit is given a negative-resistance characteristic, which enables it to maintain oscillations in the circuit o ; and a modulated wave is thus radiated from the aerial l<1>. In reception, the valve is kept in weak oscillation, and the circuit o causes the receiver to act similarly to a supergenerative receiver, enabling the signals to be heard in the telephones T.