| 摘要 |
<p>PURPOSE:To improve the response characteristic of the whole of the system according to every operation, by making feedback gains of the feedback system and the jitter feedback system larger and smaller respectively in comparison with normal values at the motor starting time. CONSTITUTION:Speed feedback system 3 which performs the speed control on a basis of the output of frequency generator 5 proportional to the rotation frequency of motor 2 driving video disc 1 or the like and jitter feedback system 4 which performs the rotation control on a basis of the output of head 7 are provided. Further, switch 15 and gain setting equipments 16 and 17 switched by switch 15 are provided in, for example, speed control circuit 6, and rotation control circuit 8 is provided with switch 18 and gain setting equipments 19 and 20 also. Switches 15 and 18 are interlocked and switched by controller 21, and gain K12 at the start time is made larger than gain K11 at the nomal time in speed feedback system 3, and gain K22 at the start time is made smaller than gain K21 at the normal time in jitter feedback system 4.</p> |
