| 摘要 |
<p>PURPOSE:To correct a tracking error in a short time and simultaneously to prevent a reproduced image from fluctuating by controlling tracking with the aid of a synchronous detection servo in the starting period of a capstan motor and with the aid of an envelope servo in an ordinary period. CONSTITUTION:In the starting period of the capstan motor 4, a phase error signal Ss formed by the synchronous detection servo is supplied to an addition circuit 16 and integrated. Then, a speed reference is corrected by detecting the direction and the absolute value of a speed error. Next, when an envelope level ENV is detected, the ENV is changed corresponding to the scanning extending to plural tracks which is executed by rotating heads 1a and 1b at the starting period of the motor 4 and a maximum value without the dislocation of the track is detected. At this time, the tracking is controlled by switching a servo system to an envelope servo system. A switching circuit 14 is controlled corresponding to the muting period of the reproducing signal of a VTR.</p> |
