GB453261A - Improvements in or relating to circuit arrangements for suppressing disturbances in wireless receiving sets - Google Patents

Abstract

453,261. Wireless receiving systems. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, Emmasingel, Eindhoven, Holland. Feb. 13, 1936, No. 4433. Convention date, April 13, 1935. [Class 40 (v)] The low-frequency amplifier of a wireless receiver is disabled for the duration of a disturbing impulse by an electrical or mechanical switch device connected at a point lying before the final amplifying valve at which no direct voltages or currents are present. In one embodiment, Fig. 1, a relay R, operated by a rectifier 7 fed from a coil L coupled to the input of the signal detector 3, breaks the connection between the grid of a low frequency amplifier 5 and its feed condenser C1 when disturbances of greater than a predetermined amplitude are received. Alternatively the relay R may short-circuit the grid resistance R2. The relay R may be operated by an auxiliary receiver tuned to a frequency adjacent that of the main receiver. In a further embodiment disturbances received on an auxiliary receiver 8, 9, 10, Fig. 3, operate a glow discharge tube G arranged to reduce the resistance of a selenium cell L forming part of a potential divider L, R4 in the grid circuit of the valve 5. Disturbances received on the auxiliary receiver 8, 9, 10, Fig. 4, may control the alternating current resistance of a dynatron valve 11, forming part of a potential divider 11, R5, in the grid circuit of valve 5, in such a way that the signal across R5 is reduced when a disturbance renders the grid 12 of valve 11 more negative.