METHOD AND APPARATUS FOR SYNCHRONIZING OF SPREAD SPECTRUM POWER LINE COMMUNICATION

摘要

PURPOSE:To establish stable synchronization of a spread spectrum signal by effecting peak detection of a full-wave rectified correlation signal and varying the lock phase in a permissible range in the neighborhood of the detected peak position, thereby reducing the influence of correlation distortion. CONSTITUTION:A power line signal from a signal line 160 is separated in a coupler 108 into commercial power and a high frequency spectrum dispersion signal. The dispersion signal is provided with automatic gain 109 and multiplied in a multiplier 100 by a psuedo-random series generation signal from a signal line 151. The output of the multiplier 100 is converted through LPF 102 and a full-wave rectifier 110 into a wave detection correlation signal which is provided to a signal line 153. The peak of the of the phase of the wave detection correlation signal is detected through variation of the phase of the reference clock signal. After the peak has been detected, the wave detection correlation signal and a correlation signal obtaining by averaging the wave detection correlation signal through the LPF 301 are compared in a comparator 302, the output 154 of which is fed to a phase control circuit 103. The output of the circuit 103 is used to control a phase variation circuit 106, whereby the input spectrum diffusion signal is synchronized to the phase and frequency of the psuedo- random series.