| 摘要 |
PURPOSE:To avoid a wow deterioration at a stationary time by counting the number of reverse rotation in a direction which changes a phase difference between a recorded track and a rotary head locus and adding a means for stopping the operation to change the phase difference when the number of reverse rotation exceeds a specified value. CONSTITUTION:In the magnetic recording/reproducing device of a helical scan system, the phase difference between the recorded track and the rotary head locus is changed, and simultaneously a reproducing output amplitude fro the rotary head is sampled and measured. An output comparison with respect to a measured value is carried out to change the phase difference in the direction of the bigger output amplitude, thereby carrying out tracking operation automatically. A direction deciding logic 14 outputs a direction reversing pulse, and a direction FF16 counts the number of the direction reversing. When the number of reverse rotation exceeds the specified value, a stopping/starting circuit for automatic tracking operation 104 stops the tracking operation which changes the phase difference. Thus, the wow deterioration at the stationary time can be avoided.
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