Signal communication system capable of recognizing reception of reception desired signal

Abstract

An input information signal is phase-modulated in a DQPSK (differentially encoded quadrature phase shift keying) modulation system. The resultant modulated signal is supplied to an input terminal of a first multiplier. A first M-bit random number generator receives transmission timing data and initial value data from a first initial value generator and generates an M-bit random numbers beginning at the initial value data. A first phase generator generates phase data corresponding to the random number and supplies the phase data to the other input terminal of the first multiplier. A first multiplier generates a first multiplied signal by multiplying the modulated signal from the phase modulator and the phase data from the first phase generator. The first multiplied signal is transmitted through a wireless or wire transmission path. A reception signal from the transmission path is supplied to one input terminal of a second multiplier. A second M-bit random number generator, a second initial value generator and a second phase generator are the same as the first M-bit random number generator, the first initial value generator and the first phase generator in configuration. The second phase generator supplies the same phase data as that of the first phase generator to the other input terminal of the second multiplier. The second multiplier generates a second multiplied signal by multiplying the reception signal and the phase data from the second phase generator. The second multiplied signal is supplied to a phase demodulator and/or phase judgement circuit.

Dependencies are inferred from the claim text.