GB385997A - Improvements relating to radio receiving apparatus - Google Patents

Abstract

385,997. Valve circuits for wireless reception. TOMLINSON, A. V., 65, Victoria Street, London.-(Union Switch & Signal Co.; Swiss vale, Pennsylvania, U.S.A.) July 8, 1931, No. 19647. [Class 40 (v).] A detector of the dry-surface contact type as described in Specification 381,206 is followed by one or more valves 4 which amplify the rectified high-frequency currents, which are subsequently eliminated by a byepass condenser 11 or other means. The detector is fed from a high-frequency valve 3a, the grid-bias of which is automatically controlled from the output of the valve 4 by a resistance 13 and condenser 16. Grid-bias for the output valve 4 is obtained from a resistance 12 shunted by a condenser 12a. According to modifications, the detector, valve 4, resistance 12 and condenser 12a are incorporated in a unit to plug in the socket of the detecting-valve in an ordinary circuit, Fig. 3 (not shown) ; the detecting-elements la, 1b are connected up for fullwave rectification and are followed by a single output valve, which may be a pentode, Fig. 4 (not shown), or a triode of large power capacity, Fig. 5 (not shown). Specification 385,998 is also referred to.