LOCAL OSCILLATOR PHASE CONTROL CIRCUIT FOR A RECEIVER OF DATA SIGNALS TRANSMITTED BY SINGLE SIDE-BAND AMPLITUDE MODULATION

摘要

A feedback circuit for controlling the phase of a local oscillator provided with frequency adjusting means and delivering a local carrier wave for demodulating a data signal transmitted by single side band amplitude modulation, the said feedback circuit comprising at least one sign multiplier (21) producing the product of the sign of the local demodulation carrier shifted by a phase difference of pi /4 multiplied by the sign of the data signal to be demodulated, followed by a sign coincidence auto-correlator (22) which controls the said frequency adjusting means and correlates two versions of the signal delivered by the sign multiplier (21), one of the two versions being delayed relative to the other by an odd multiple of one fourth of the period of the carrier used for the amplitude modulation on transmission.