| 摘要 |
<p>PURPOSE:To make a vacuum column, a loop sensor, etc., small-sized and reduce the power consumption of a reel motor by switching the constant of a compensating filter circuit in accordance with the rotation state of a capstan to control the response of a reel motor. CONSTITUTION:For example, before the mode where a magnetic tape 1 is run forward or backward, only a switch 35 is turned on and switches 34 and 36 are turned off. Consequently, a detection signal 15 obtained by detecting the loop position (Xx or x2) of the magnetic tape in a vacuum column 13 by a loop sensor 14 is supplied to a PWM converting circuit 18 through a compensating filter circuit 32, which has an optimum constant which is so selected that an optimum response is attained as shown by a broken line in case of forward running/backward running, and the switch 35. The rotation of a capstan motor 12 is controlled most suitably for forward/backward running. Thus, most suitable reel rotation control is possible with respect to power consumption and steady- state deviation.</p> |
