| 摘要 |
PURPOSE:To set an optical pick up between specific tracks with a simple circuit constitution by detecting a track cross signal through an optical head movement and automatically driving the head in a direction in which a cross cycle thereof is increased. CONSTITUTION:A tracking error signal from the optical head is amplified 1, pulsated 2 and the cycle of a pulse waveform is counted 3. A counter 3 is cleared for ever edge of the pulse waveform, data before the clear is latched 4, 5, the difference between the respective latched data is is taken as a positive or a negative by a comparator 6, applied to a voltage generating circuit 7 to generate a position and negative voltage (g) and applied to as slide feeding motor 10. When the head is moved rightward or leftward to the track, the track cross signal is detected, the change in the cross cycle is taken out, thereby, the head is automatically driven in the direction in which the track cross cycle is increased.
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