| 摘要 |
PURPOSE:To suppress a reactive power loss and the like of a motor by adding the output of an envelop detection circuit sensing the amplitude fluctuation of a rotation detector (FG) to the output of an F/V converter and thereafter comparing the resultant thereof with a reference level by a comparator. CONSTITUTION:The output of an envelop detection circuit 11 sensing only the amplitude fluctuation of an FG signal is inputted to a composer 13 connected to a speed comparator 6 via an amplifier 12, and is added to the output of the speed comparator 6. Thereby, an unnecessary F/V error signal due to the assembling accuracy of the FG itself and the voltage fluctuation of a power supply which is sensed as the amplitude fluctuation of the FG signal can be removed or suppressed at a lower level. Thereby, without deteriorating the control performance of a motor 1 for a video disc, a VTR and the like which is required a high speed control response, the reduction of the reactive power loss and the suppression of the unnecessary speed fluctuation thereof can be attained. |
