| 摘要 |
PURPOSE:To shorten the pull-in time of a tracking servo and to eliminate the detection of a pick-up moving direction by generating a sufficiently large driving signal at the pick-up in the direction to suppress the relative speed of the pick-up to a track automatically at the time of an off-track condition. CONSTITUTION:At the period B1-B3 of an off-track condition, a tracking servo is loaded, at the period A0-A3 of an off-track condition, a tracking driving signal has a code reverse to the code of a tracking error signal at the time of the on-track condition immediately before the off-track condition is obtained and an absolute value is V (V>0). Consequently, when the pick-up is moved to the track and the off-track condition is obtained, a driving force V functions at the pick-up in the direction to stop the movement automatically. Thus, at the time of the on-track condition, the average force of the servo functions and at the time of the off-track condition, the driving force functions in the direction to stop the action of the pick-up to the track, and when V is made larger, the pull-in time of the tracking servo is shortened.
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