CLOCK EXTRACTION DEVICE FOR DISK REPRODUCING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a clock extraction device for a disk reproducing device for securing the stable reproducing operation of an information signal by automatically securing a desired operation point though the reading speed of the information signal of a disk-like information recording medium is changed remarkably. SOLUTION: A speed detector 6 detects the reading speed of the information signal with input from a voltage-controlled oscillator 5 and a gain commanding device 7 designates a gain corresponding to the speed to switch the output current value of a charge pump 4 so that the loop gain of the clock extraction circuit may become the desired operation point. A frequency comparator 8 detects a frequency difference between an information signal from a light pickup 2 and output from the oscillator 5 and controls a charge pump 4 so as to reduce the difference. A phase comparator 3 controls the pump 4 similarly so as to eliminate the phase difference of the same input.