Spread spectrum communication system

摘要

A spread spectrum communication system has a plurality of transmit ends capable of simultaneous communications and at least one receive end. Each of the transmit ends modulates digital information by a PN code to provide a spread signal, modulates a carrier by the spread signal to provide modulated signal, and then transmits the modulated signal to the receive end. These transmit ends use the same PN code for spreading the respective digital information and use carriers having different frequencies from each other so that spectrums of at least two of the modulated signals overlap each other. The receive end receives signals transmitted from the transmit ends to provide a received signal, frequency-converts the received signal to provide a converted signal, and calculates a correlation between the converted signal and the PN code to recover the digital information transmitted from the desired transmit end. This receive end extracts a signal having a center frequency which corresponds to the carrier frequency of the desired transmit end to provide the converted signal.