GB436922A - Improvements in or relating to modulated carrier wave circuit arrangements - Google Patents

Abstract

436,922. Valve modulating circuits. TELEFUNKEN GES. FUR DRAHTLOSE TELEGRAPHIE, 12, Hallesches Ufer, Berlin. Oct. 25, 1934, No. 30675. Convention date, Oct. 25, 1933. [Class 40 (v)] The output from a carrier - wave amplifier R is modulated by signal voltage applied through a transformer M both to the anode and to the screening grid, the circuit being so arranged that the variations in screen-grid voltage are not in linear relation with the anode voltage variations, but are designed to give linear modulation of the output of the valve R. As shown, a portion of the tapping on the transformer secondary is connected in suitable phase to the grid circuit of an auxiliary valve V, the plate circuit of which includes a resistance which lies in the screen-grid circuit of the main valve R. The Specification as open to inspection under Sect. 91 comprises other circuit arrangements in which the transformer secondary is connected across the anode and cathode and the screengrid is connected directly to a tapping on a potentiometer across the secondary. The H.T. source may be placed between the cathode and the potentiometer, and a further source with its negative end towards the screen-grid may be placed in the screen-grid lead. The tapping may be on the transformer secondary coil itself ; or the transformer may have separate secondaries for the plate modulation and screen-grid modulation respectively. This subject-matter does not appear in the Specification as accepted.