Demodulator for psk-modulated signals.

摘要

A demodulator is disclosed for a PSK-modulated transmission signal in which the time average value of the frequencies thereof are equal to the carrier frequency. A mixer receives and mixes the PSK-modulated transmission signal with a signal from a local variable frequency oscillator (1) and the output thereof is converted (5) to a square wave which is used to reconstruct the original digital modulation data. A pulse counter (8) receives and counts the square wave signal for every period of time which is n times a time slot of a digital signal and a subtractor (11) provides a difference between the count value from the pulse counter and a reference count number. The subtractor output is converted (12) to an analog signal which controls the local oscillator frequency.