CLOCK REPRODUCING CIRCUIT

摘要

A clock reproducing circuit for reproducing a clock signal accurately from a PSK modulated signal so as to sample the I's aperture point. The phase of th e PSK modulated signal is rotated by a phase rotation circuit (1) by a predetermined angle according to the transition angle between adjoining reception points, and the phase difference due to the time difference betwee n the zero cross point position at which the adjoining reception points of the phase-rotated PSK modulated signal intersect the I-axis or the Q-axis and th e time center position of the adjoining reception points is detected by a phas e difference detecting circuit (2). According to the phase difference detected , the oscillation frequency of a voltage-controlled oscillator (5) is controll ed to accurately reproduce the clock to be sampled at the I aperture.