| 摘要 |
PURPOSE:To return a reproducing position to a signal track in which the latest position index information written in a storage means has been recorded, by executing a search, when the reproducing position on a disk by a pickup has been deviated from the signal track, exceeding a prescribed time. CONSTITUTION:For instance, a strong impact is given from the outside, the time when a light beam projected from an optical pickup 3 has been deviated from a signal track of a CD 1 is long, an off-state of a transistor 21 passes through a prescribed time corresponding to a charging time constant of a time constant circuit 26, and when a terminal voltage of a capacitor 25 reaches an 'H' level, a microcomputer 7 sets position index information of a sub-coding signal written in a RAM 17, as a target, and generates a control signal for driving the light beam of the optical pickup 3. In this case, the position index information written in the RAM 17 is that which has been recorded in signal track immediately before the light beam is deviated from the signal track, therefore, the optical pickup 3 is controlled so that the light beam returns to the signal track.
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