| 摘要 |
<p>A tracking-servo-system controller in an optical-disk player according to the present invention uses a high-pass filter (1) to extract from a readout signal an alternating-current component which is not affected by variations in the reflectance of a disk, and produces a control signal for initiating a pull-in operation of the tracking servo system based on the alternating-current component. Firstly, a comparator (2) detects a zero crossing of the alternating-current component. Secondly, a pulse generator (3) produces a pulse on the zero crossing. Thirdly, a D flip-flop (4) is activated by the pulse. An output of the D flip-flop is sent as the servo control signal to the tracking servo system. The tracking servo system starts the pull-in operation on the zero crossing of the alternating-current component. It is thus possible to achieve a stable servo irrespective of variations in the reflectance of the disk. <IMAGE></p> |
