Demodulator comprising a phase shift circuit for controlling outputs of

Abstract

A demodulator responsive to baseband signals from a coherent detector having an automatic equalizer part for supplying equalized signals to derive transmitted datum and a phase control part responsive to equalized signals. The automatic equalizer part includes a delay member with a plurality of taps and variable attenuators connected to the respective taps of the delay member. The phase control part is provided with a phase shift circuit such as a coherent detector and a control circuit for detecting phase variation components of equalized signals. Further, the control circuit feeds phase variation components detected to the phase shift circuit and simultaneously supplies error signals which are dependent on phase variation components to the respective variable attenuators of the automatic equalizer.