| 摘要 |
PURPOSE:To stop track-jump effectively by restraining the gain of tracking amplifier not to become high by a latch output when a false tracking signal to show an error of the optical disc is detected. CONSTITUTION:The output signal of an error detecting circuit 1 which receives reproduction RF signal reflected from an optical disc is retained by a latch circuit 2 for a time which approximately corresponds to one rotation of the optical disc. The tracking error signal is supplied to a tracking coil Lt through a tracking amplifier 6. The tracking amplifier 6 is controlled so that its gain becomes high when the tracking error signal of shock nature is detected at the detection circuit 3. Further, by supplying the output of the circuit 2 to an AND gate A through an inverter IV, the output of the circuit 2 is not supplied to the amplifier 6 when an output is made from the circuit 3. In this way, the track-jump is effectively avoided. |
