| 摘要 |
<p>PURPOSE:To suppress the generation of jitters by increasing and reducing the loop gain when the disturbance is large and small respectively. CONSTITUTION:The pulse showing the revolution of a drum 2 is supplied from the magnet bars 3 (3A, 3B) and a pulse generator head 5. While a reference signal separated from a video signal is supplied to a phase loop 6 and added with the speed error signal given from a speed loop 8 to be supplied to a gain switching circuit 10. The disturbance is detected by an acceleration sensor 11 and then discriminated 12. Then the resistance terminals 22 (22A-22D) connected to a terminal 23 of the circuit 10, and the output phase is compensated by a filter 13 to give the control drive 14 to a drum motor 1. In such constitution, the anti-rolling characteristics can be improved and the generation of jitters are suppressed for a servo circuit.</p> |
