GB458031A - Improvements in wireless receiving circuits - Google Patents

Abstract

458,031. Valve circuits for wireless reception. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, Emmasingel, Eindhoven, Holland, and MEYER, L. W., 28, Sundorne Road, Charlton, London. June 6, 1935, No. 16476. [Class 40 (v)] The amount of retroaction in the circuit of a back-coupled amplifying valve or local oscillator is varied electrostatically in accordance with signal strength for automatic volume control. In one embodiment, the anode coil 20, Fig. 1, of the local oscillator 18 of a superheterodyne receiver is shunted by a valve 16 in series with a condenser 22, the impedance of the valve 16 being lowered as the signal strength increases by connecting its control grid to the junction of the resistances 12, 13 in the anode circuit of the leaky-grid second detector 10. In a second embodiment, Fig. 2, the anode current of a detector valve 23 is passed through a coil 29 and determines the position of the armature 30 carrying one of the electrodes 31 of a variable condenser 31, 32 shunting the reaction circuit 24, 25. Provision may be made for maintaining constant the critical reaction setting over the tuning range such as, for example, a compensating condenser operated by the tuning control. Specification 445,098 is referred to.