GB415796A - Improvements in or relating to thermionic valve amplifiers and circuits therefor - Google Patents

Abstract

415,796. Valve amplifying circuits. WILSON, J. C., and BAIRD TELEVISION, Ltd., 58, Victoria Street, London. March 3, 1933, No. 6565. [Class 40 (v).] In order that an amplifier may be free from amplitudedistortion and phase-distortion throughout the range of frequencies used in television, the decoupling circuits whereby either the plates or the grids of successive valves are decoupled from one another are replaced or supplemented by distortion-correcting circuits. Thus, a point on the anode resistance of each of the screenedgrid valves of an amplifier (Fig. 1, not shown), may be connected to earth through a decoupling circuit (9, not shown) which, in order that it may correct distortion, consists of an inductance and condenser in series. In a modification, several points on the anode resistance may be earthed through condensers of different sizes or through large condensers in series with resistances. Alternatively, the grid-decoupling circuit 17, 18, Fig. 3, may be shunted by the correcting circuit 19. The grid-bias battery 20 may be transferred to the place of the condenser 18 (Fig. 2, not shown). In other modifications, several tapping-points on the anode resistances of the valves may be earthed through condensers or tuned circuits. Specification 381,254 is referred to.