| 摘要 |
PURPOSE:To restrain a track-jump by establishing an error circuit to detect the top level of an RF signal and by muting the tracking error signal and focus error signal by the output of the error detection output. CONSTITUTION:An RF signal reflected from an optical disc is inputted to an error detection circuit 1, and the circuit 1 detects the top level of the RF signal. The detection signal of the circuit 1 is retained by a latch circuit 2 for about a time corresponding to one rotation of the optical disc, and inputted to an AND gate through an inverter IV. The tracking error signal and focus error signal are supplied to a tracking coil Lt and focus coil Lf through amplifiers 6 and 7 respectively. Transistors Q1 and Q2 are connected by the output of the circuit 1. And, a shocking circuit 3 detects the level of abnormal cycle which is included in the tracking signal. The track-jump is restrained in this way. |
