OPTICAL INFORMATION PLAYER

摘要

The optical information read apparatus includes an optical head for producing two detected signals whose phases vary accoriding to a tracking error of the head. A tracking error detecting circuit produces an error signal corresponding to a phase difference between the two detected signals. The optical head is controlled in response to the tracking error signal. The tracking error detecting circuit has a test circuit for checking a correlation between the states of the two detected signals, and for making the tracking error signal invalid when there is no correlation between the states of the two detected signals.