FOCUSING GAIN CONTROL CIRCUIT OF REPRODUCING APPARATUS IN AN OPTICAL DISK

摘要

A circuit is for compensating the sensitivity variation of the focus error which is generated by the distance between a focus and a track. The circuit comprises a track error detecting means (400) for converting the distance between the focus and the tracks into the electric signal, a gain control signal generating means (200) for generating the control signal being in reciprocal proportion to the magnitude of the detected track error, an envelope detecting means (100) for detecting the envelope of the modulated high frequency in the search mode, and a gain control means (300) for controlling the focus loop gain according to the gain control signal.