| 摘要 |
<p>PURPOSE:To shorten the phase pulling time immediately after setting a speed of a capstan motor and to make it constant at the same time by a phase control of the magnetic recording and reproducing device. CONSTITUTION:The number of pulses of a pulse signal of a frequency in proportion to a rotating speed of the capstan motor 2 is stored by a counter 6. A 1st rotary position data of a rotary head 4 is stored in a storage circuit 16. A delay time is calculated by a delay time generating circuit 10 from a count data of the counter 6, the stored 1st rotary position data and a 2nd rotary position data of the rotary head 4. Then, the capstan motor 2 is started up in timing delayed by the above delay time on a pulse signal to be outputted from a head switching signal output unit 14 by a start-up control circuit 8. By this method, the phase drawing time can be shortened to be kept constant in simple constitution, and even when changes in external environment such as temp., etc., take place, the operational precision can be maintained.</p> |
