GB247563A - Improvements in or relating to receiving apparatus for high frequency electric signals - Google Patents

Abstract

247,563. Westinghouse Electric & Manufacturing Co., (Assignees of Beers, G. L.). Feb. 10, 1925, [Convention date]. Void [Published under Sect. 91 of the Acts]. Thermionic heterodyne receivers, amplifiers, and detectors. - With the object of preventing radiation of locally-generated oscillations from a supersonic receiver, the loop aerial is connected at one end to the grid of the first detector 2, at the other end through a balancing condenser 5 to the plates, and at its middle-point to the filament through a coil 4 on which the local oscillations are impressed. The local oscillations may be produced by a separate oscillator, or, as shown, the coil 4 may be tuned and coupled to a coil 6 in the plate circuit of the valve 2. The supersonic beats are passed through a transformer 7 to an amplifier 8, and thence to the second detector 11. The local oscillations are preferably of about half the frequency of the incoming waves, so that their second harmonic combines with the incoming waves to produce the supersonic beats. The capacity of the condenser 5 should be substantially the same as that between the grid and filament of the valve 2.