Information recording and reproducing apparatus

摘要

An apparatus operates for recording and reproducing information on and from a recording medium formed with a track and pre-pits. The track has a wobble. The pre-pits are in a predetermined phase relation with the wobble of the track. The apparatus includes a pickup for reproducing a signal from the recording medium. A limiter operates for limiting an amplitude of the signal reproduced by the pickup in response to a limiting level, and thereby processing the signal reproduced by the pickup into a limiting-resultant signal. A filter operates for suppressing components of the limiting-resultant signal, and thereby processing the limiting-resultant signal into a filtering-resultant signal. The components have specified frequencies, and are caused by the pre-pits. The limiting level for the limiter is generated in response to the filtering-resultant signal. A signal caused by the wobble of the groove is extracted from the filtering-resultant signal.