| 摘要 |
<p>PURPOSE:To decrease the servo loop gain of an APC control circuit and to suppress the damping level by decreasing apparently the relative lead amount of a rotary detecting signal to a reference signal in synchronizing with a transversal shaking preventing pulse. CONSTITUTION:When the 2nd capacitor C2 is discharged by the input of the transversal shaking preventing pulse P, a potential of a connecting point between the 2nd resistor R2 and the 3rd resistor R3 is decreased, the charging period of the 1st capacitor C2 is delayed, resulting that a quasi-stable period tau of the 1st monostable multivibrator 3a is prolonged. This quasi-stable period tau approaches the substantial quasi-stable period tau0 attended with the potential increase at the connecting point. Thus, the reduced amount tauD of the phase difference is maximized immediately after the generation of the transversal shaking preventing pulse P having the largest actual lead phase amount and the amount of reduction tauD approaches gradually (0) as the lead amount is decreased, resulting in suppressing the servo loop gain.</p> |
