| 摘要 |
PURPOSE:To produce a tracking actuator control signal to detect dust or flaw on a track and to cope with it by splitting the frequency band of a tracking error signal. CONSTITUTION:A high pass filter 16 receives a tracking error signal as an input signal, the frequency band of the signal is split to detect only the high frequency component of the tracking error signal to form an output signal caused by the effect of dust and flaw. Then a control signal generating circuit 17 outputs a control signal restoring a tracking actuator to a prescribed position for a prescribed period only when a signal is outputted from the high pass filter 16 and shields an input signal from a servo amplifier 12 while the control signal is outputted. Then the signal selection circuit 14 passes the signal when the output signal of the control signal generating circuit 11 is inputted. Thus, the presence of dust and flaw on the track is detected clearly and track jump, instability of the tracking servo circuit and switching noise caused by dust and flaw are avoided.
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