| 摘要 |
<p>PURPOSE:To eliminate the tracking dislocation of a rotating head even when the pulse intervals of sample holding pulses are not the same, and to execute a correct tracking by switching the gain of a tracking dislocation signal in response to a measuring signal from a measuring circuit, and outputting it to a control circuit. CONSTITUTION:The pulse intervals of second holding pulses p2 applied from a delay circuit 12 are measured, and a pulse interval measuring circuit 16 is provided which outputs the measuring signal indicating a measured value. Further, a gain switching circuit 17 is provided which is set between a second sample holding circuit 8 and a driving circuit 13, switches the gain of the tracking dislocation signal in response to the measuring signal from the pulse interval measuring circuit 16, and outputs the signal to the driving signal 13. Thus, even when the pulse intervals of the sample holding pulses are not the same, the tracking dislocation is eliminated, and the correct tracking can be attained.</p> |
