GB445030A - Improvements in or relating to radio and other modulated carrier wave receivers - Google Patents

Abstract

445,030. Valve circuits for wireless reception. MARCONI'S WIRELESS TELEGRAPH CO., Ltd, Electra House, Victoria Embankment, London.-(Assignees of Chittick, K. A.; 120, Wayne Avenue, Haddonfield, New Jersey, U.S.A.) Sept. 28, 1934, No. 27879. Convention date, Sept. 30, 1933. [Class 40 (v)] A carrier wave receiver has at least two A.V.C. systems one of them producing a control potential from signal energy in a point in the circuit where the selectivity is comparatively low and controlling the gain preceding said point. The selectivity of the receiver may also be controlled. The invention is described with reference to a superheterodyne receiver comprising R.F. amplifier 1, frequency changer 3, I.F. amplifier 5 and demodulator 7, the three latter being diode - pentodes. The tuned anode circuits 35, 87, 123 are coupled to coils 77, 113, 151 respectively each feeding the diode portion of the succeeding valve, the negative D.C. potentials produced across the load resistances 79, 115, 153 respectively being applied to the suppressor grids 15, 51, 99 respectively of the preceding valves 1, 3, 5. Delay voltages are provided in the diode circuits by the cathode resistances 75, 109, 147 respectively which also produce the steady grid voltages. Increasing negative bias on the suppressor grids reduces the amplification of the controlled valves and also their anode impedances to broaden the response of the associated tuned circuits.