LIGHT CLOCK GENERATING CIRCUIT AND OPTICAL DISK UNIT

摘要

A light clock generating circuit capable of detecting a wobble signal with high accuracy even at an operation changeover from reproducing to recording, and generating a proper light clock with little jitter. Light clock is generated from a wobble signal obtained by changing stepwise by a gain control circuit a VGA gain in the latter stage of split light receiving element during a specified period immediately after record starting involving a changeover from reproducing to recording to thereby suppress a change in wobble signal from immediately before record starting to immediately after record starting and slow down a gain change in constant wobble signal amplitude AGC. Accordingly, light clock with little jitter restricted in high-pass fluctuation of wobble frequency even at a reproducing/recording changeover can be generated.