TRACKING ERROR GENERATING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a tracking error generating device performing a constant tracking control even when a linear velocity is changed. SOLUTION: This tracking error generating device detects peaks of dark sides of middle areas 18, 19 equivalent to neighborhoods of the center of the light spot of a reflected light from an optical disk with envelope detecting circuits 22, 23 and computes the difference of detected peak values in a differential amplifier 29 to output it as a tracking error signal and also changes the time constant of the circuit 22, 23 in accordance with the linear volocity of a track by a time constant control circuit 25.