CIRCUIT FOR REGENERATING THE CARRIER OF A SIGNAL MODULATED IN AMPLITUDE AND PHASE BY DIGITAL SIGNALS

摘要

A circuit for regenerating the carrier of a signal, modulated in amplitude and phase by digital signals, which estimates the phase error of the recovered carrier by a comparison made between base-band components obtained by quadrature demodulation of the signal and suitable decision thresholds. Actual location of the signal in regions of a cartesian signal plane is compared with its expected location, and correction signals are applied to a local oscillator regenerating the carrier in accordance to the region in which the signal is located.