Apparatus for demodulating phase modulated WAVE

摘要

An apparatus for demodulating a phase modulation wave reduces an error rate of a demodulating circuit to perform a delay detection of an n-phase shift keying modulation wave without raising a clock frequency. When converting the received n-phase shift keying modulation wave into a rectangular wave, a waveform converting circuit for converting the n-phase shift keying modulation wave into a rectangular wave of a duty ratio which is larger or smaller than 50% is used. The rectangular wave is clocked through parallel registers of different lengths, outputs of the registers being operated on by exclusive-OR gates with the rectangular wave. Outputs of the gates are applied to respective one of a pair of counters, operated by a common clock signal, during periods of equality of outputs signals of the gates to provide a function of discriminating reproduction. A parallel/series converting circuit arranges upper bits and lower bits for reconstruction of each symbol of an original data message.