GB763237A - Improvements in and relating to signal voltage amplitude limiters and phase discriminators - Google Patents

Abstract

763,237. Non-linear circuits; phase discriminators. GENERAL ELECTRIC CO. April 13, 1953 [April 15, 1952], No. 10014/53. Classes 40(5) and 40(6) In a circuit for deriving limited signals from applied A.C. input, a pair of reversally connected diodes 6, 7, Fig. 1 are arranged to shunt the circuit and are biased in opposite senses in accordance with the wave shape of the applied signal. A.C. fed in at terminal 2 is applied to selsyn 1, the output of which is fed over resistor 3 to the diodes 6, 7. The A.C. is also fed over transformer 10 to rectifiers 11, 12 to develop bias voltages B, C, Fig. 4, the magnitude of which is determined by ganged potentiometers 8, 9. A signal S, derived from the selsyn is limited by the bias applied to the diodes 6, 7 curve F, Fig. 4 so that a limited signal LS is fed out at terminals 5. The circuit may be made phase-selective, Fig. 2 by arranging that the diodes 6, 7 are only biased off during alternative half-cycles curves D, E, Fig. 4. As a result, signals which are in-phase are limited in the manner described with respect to Fig. 1 but out-of-phase signals are suppressed since neither diode 6, 7 is biased. Signals which are intermediate in phase will be passed in part and partly suppressed so that a pair of oppositely connected circuits may be connected in opposition, Fig. 3 the outputs being rectified by diodes 21, 22 feeding loads 23, 24 to develop a D.C. signal at terminals 27 with a polarity and magnitude varying with the phase and amplitude of the applied A.C. or as a, phase of a constant amplitude phase modulated signal.