Spread spectrum communication system for error compensation of carrier frequency

摘要

A transmitter and a receiver of a spread spectrum communication system for compensating carrier frequency offsets between the transmitter and the receiver. The transmitter includes: a first multiplier for multiplying a pseudo noise signal and input data intended for transmission; a differential encoder for differentially encoding a signal outputted from the first multiplier; a modulator for modulating a signal outputted from the differential encoder; a second multiplier for multiplying the signal modulated by the modulator and a transmitting carrier and for outputting a spread spectrum signal; and an antenna for propagating the spread spectrum signal in the air. The receiver includes: a generator for generating a receiving carrier corresponding to a frequency offset signal; a first multiplier for multiplying a spread spectrum signal received from the transmitter and the receiving carrier and outputting the multiplied signal as a first low frequency signal; a second multiplier for multiplying the spread spectrum signal by a modified carrier in which the receiving carrier is modified by a given phase, and outputting the multiplied signal as a second low frequency signal; a differential detector for detecting a phase rotation amount between each complex digital signals; a correlator for correlating a pseudo noise code with the phase rotation detected by the differential detector; and a frequency offset measurer for measuring a frequency offset between the spread spectrum signal and the receiving carrier by using the signal from the correlator and outputting the frequency control signal for adjusting the receiving carrier signal.