| 摘要 |
<p>PURPOSE:To eliminate synchronization errors and to improve accuracy by calculating a control quantity from the rotation frequency and the rotation phase error of a capstan motor and adjusting the control quantity of the capstan motor to the phase error so that the level of a video signal may become maximum. CONSTITUTION:A CPU 211 obtains the difference between count values latched by a latch 213 and a latch 214, detects the phase error between a reference signal 100 and a P-CTL signal from the difference, mixes a speed error with the phase error by an operation, prepares a motor control signal to rotate a capstan motor 22 in a prescribed phase at a prescribed speed and rotates the capstan motor 22 based on the control signal. The CPU 211 shifts the control quantity of the motor control signal by a prescribed quantity, seeks for a point where the peak level is maximum, sets the level at a target value, changes the phase quantity of the motor control signal so as to obtain the target value. Thus, the synchronization errors can be eliminated and the accuracy can be improved.</p> |
