GB238261A - Improvements in or relating to wireless receiving circuits - Google Patents

Abstract

238,261. Robinson, J., and Kinman, T. H. March 11, 1924. Thermionic amplifiers and detectors.-Relates to oscillating-valve receivers in which the grid condenser or leak resistance is so adjusted that the frequency of an exciting, pulsating or " squegger " effect is varied by the incoming signals. To increase the amplification, the frequency of the local oscillation is made equal to the signal frequency. In Fig. 2, the ordinary leak resistance of the oscillating receiver 3 is replaced by a two- or three-electrode valve 9, which shunts the grid condenser 4, and is in series with the aerial system 1, 2 across the grid and filament of the valve 3. The aerial circuit may be inserted across the grid and filament of the valve 9, or as shown in Fig. 4, the unearthed end of the aerial 2 may be connected to the grid only of the auxiliary valve 10. The pulsating or quenching frequency is made supersonic for telephony. For heat reception the circuit 13, 14, Fig. 5 is tuned to the supersonic frequency, and coupled to a local oscillator 15. Fig. 6 shows a circuit for obtaining both high and low frequency amplification. The valve 16, acting as a variable grid lead or pulsator across the grid condenser 4, serves also to amplify the low-frequency currents fed from the plate of the main valve 3 across the transformers 17, 18. Specifications 153,690 and 159,377 are referred to.