| 摘要 |
<p>PURPOSE:To realize control extending to wide range which includes very low speed and to easily change the rotating speed of a capstan motor by controlling a reference signal and a control signal so that the phases thereof are made to synchronize each other and simultaneously controlling the capstan motor so that it is always a closed-loop state. CONSTITUTION:The frequency of the control signal (c) recorded on a magnetic tape 513 is in proportion to the rotating speed of the capstan motor 504. Therefore, the frequency of the signal (c) and the frequency of the reference signal (h) when a digital command value is taken as a reference digital command value become equal and a phase detection digital value corresponding to the detection digital signal (p) of a phase detector 206 becomes smaller or larger than a prescribed digital value according as the phase of the signal (c) is delayed or advanced from a prescribed value. Then, the digital command value is selected so as to be (+) or (-). Thus, phase error is made small by controlling the traveling speed of the magnetic tape 513. By making a selection term in proportion to the phase difference, the control of phase synchronization is accurately executed.</p> |
