| 摘要 |
PURPOSE:To execute rapidly and stably a track jumping action at the time of tracking retrieving by detecting that a track signal voltage comes to be a constant voltage level or below after passing through a positive negative converting zero cross point to an optical spot and a track groove position and completing a brake pulse. CONSTITUTION:A track error signal voltage 20, after passing through a zero cross characteristic which is the positive negative converting point of the track error signal voltage 20 at a mirror surface 17 to an optical spot and a track groove position, passes through the first maximal part peak value of the signal voltage 20 to appear next, comes to be a constant voltage value or below, and then, turns off a brake pulse. Namely, a peak detecting circuit 21 detects a peak F point to appear first after the track signal voltage 20 passes through a positive negative converting zero cross point B point on the mirror surface 17. Thus, even when a track pitch P is different, a stable tracking jumping action can be obtained in a short time.
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