| 摘要 |
<p>PURPOSE:To obtain a stable capstan control by providing a phase comparison means that performs the operation of phase comparison between the pulse of positive polarity and the signal of two field periods of an oscilator output after the lead-in of a phase, and a means that supplies the output error signal of the phase comparison means to a motor. CONSTITUTION:In reproducing, switches SW1-SW3 and a switch SW5 are switched to each of contact P side of them. A reproducing control signal S20 is reproduced by the differential characteristic of a control head 20 and the signal is supplied to an amplifier 21 and is converted to a positive polarity pulse signal S21 and a negative polarity pulse signal S22. Furthermore, by inputting the signals S21 and S22 to a positive polarity pulse sampling circuit 41, generating a signal S23, for example, using a flip-flop which is set at the trailing edge of the negative polarity pulse signal S22 and is reset at the trailing edge of the positive polarity pulse signal S21 in its inside, and taking AND between the signal S23 and the positive polarity pulse signal S21 at an AND circuit, it is finally converted to a signal S24. Thereby, the stable reproducing of a capstan control signal can be obtained.</p> |
