| 摘要 |
<p>PURPOSE:To eliminate a need for providing a head, etc., independently in order to detect the rotation of a drum and to reduce the number of parts by controlling the rotational speed of a drum motor by using a pilot signal included in a reproduced signal obtained from a head. CONSTITUTION:The pilot signal is detected from among the reproduced signals RF obtained from the heads 18 and 19. The frequencies of this pilot signal and a first reference signal AFCCK are compared with each other, and the drum motor 20 is controlled corresponding to thus obtained frequency difference. Accordingly in a state that the rotational speed of the drum is converged within a specific range, the pilot signal and a second reference signal APCCK are phase-compared with each other, and the drum motor is controlled corresponding to thus obtained phase difference. As a result, the number of parts can be decreased and the constitution can be simplified, and also the drum can be accurately driven in rotation. Thus an excellent drum control circuit for tape reproducing device with helical scan system can be obtained.</p> |
