GB429428A - Improvements in radio receiving systems and in valves used therein - Google Patents

Abstract

429,428. Valve circuits for wireless reception. ROBINSON, E. Y., Garvary, Dryden Road, Bush Hill Park, Enfield, Middlesex, and ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Crown House, Aldwych, London. Nov. 8, 1933, Nos. 31157 and 33212. [Classes 39 (i) and 40 (v)] In a receiver comprising two high-frequency amplifiers the gain of said amplifiers is controlled by potentials derived from the output of the first and the input to the second respectively. As shown the grid bias for highfrequency amplifying valves 1, 2 is derived from the load resistance 7 of a diode rectifier 6 incorporated in the valve 2 and fed through condenser 5 with the whole of the voltage from the secondary of the coupling transformer 12 from a tapping of which the grid of valve 2 is fed with high-frequency energy. Alternatively a condenser potential divider may be connected across the coil 12 for supplying the valve 2. In order to obtain a constant output from varying signals applied to the valve 2, the valve may be arranged to have a hyperbolic characteristic connecting grid volts and mutual conductance. In a further embodiment Fig. 3, (not shown), the valve 2 has a plurality of grids arranged for volume control by the method described in Specification 408,256 the anode being screened from the input grid and the gain of the valve varying hyperbolically with the bias on the gain controlling grid. The valve may contain one or more diodes and the anode may be led out of the valve at a point remote from the leads from the other electrodes, additional screens in the form of added flanges or the like being provided therein to reduce the capacity from anode to grid and anode to diode or diodes. Specifications 377,307, 408,531, and 413,390 also are referred to.