TWO-PHASE/FOUR-PHASE MODULATED COMB-SHAPED SPREAD SPECTRUM COMMUNICATION SYSTEM

For the communication between a transmitter (2) and a receiver (3) through a transmission channel (4), an expansion transmission frame is provided on the transmission side. To constitute the expansion transmission frame, first basic series comprising a two-phase or four-phase chip is preapared. A finite period series is formed of one or more basic series. The spectrum of the finite period series is comb-shaped. Then the expansion frame is constituted of the finite period series and one or more chips which is duplicate or are duplicates of each end of the finite period series and is or are added to each end outside of the finite period series. On the reception side, a matching filter of the finite period series before expansion is provided for demodulation. In short, the invention simplifies the construction of the communciation device by using a two- or four-phase signal.