GB801548A - Demodulator - Google Patents

Abstract

801,548. Phase-sensitive circuits. BENDIX AVIATION CORPORATION. Jan.24, 1956 [Feb. 10, 1955], No. 2358/56. Class. 38 (4). In a demodulator arrangement, Fig. 2, wherein an input signal, Fig. 7, at terminals 20, 21 produces a differential current flow in output or load windings 35, 36 according to the phase of the input signal compared with a reference voltage, Fig. 6, applied at terminals 38, 39, and its magnitude, the currents through the load windings which are equal during alternate halfcycle, Figs. 11, 12, are rendered unequal as in Figs. 14, 15 by the application of the input signal to a transistor 29. Diodes 32, 33 are rendered conductive alternately during alternate half cycles and the current flow in the corresponding load winding is determined by the input signal and bias network 30, 31. An additional bias network and resistor in a modification, Fig. 3 (not shown), form a voltage divider from the collector circuit whereby the transistor is biased to reduce the no-signal current through the ineffective load winding when the current through the other winding is increased. In further modifications. Figs. 4, 5 (not shown), the reference voltage is applied to the two halves of the bridge circuit through two separate transformers, and in the latter Figure the provision of an artificial centre tap allows a two-terminal output to be taken.