| 摘要 |
PURPOSE:To stabilize the drive of a tracking servo circuit and also to eliminate the switching noises by detecting the dust and scratches on a track from the waveform of a tracking error signal, and setting a tracking control input signal when the presence of said dust and scratches are confirmed. CONSTITUTION:A differentiating circuit 8 and a comparator 10 detect clearly the states of the dust and scratches on a track. Then a tracking servo loop can be switched when the presence of the dust and scratches is confirmed on the track. Furthermore a control signal generating circuit 11 functions to elimi nate the track jumping actions, the unstable drive of a tracking servo circuit and the switching noises due to the dust and scratches on the track.
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