| 摘要 |
PURPOSE:To restrain the generation of wow and flatter upon high-speed rotation, by a method wherein a gain in a rotating number control system is regulated in accordance with a DC voltage from a phase comparator in a reference signal generating circuit. CONSTITUTION:A phase comparator 1 compares the phase of a reference signal Fin with the phase of a dividing signal from a divider 5 and outputs a DC voltage VC in accordance with a phase difference. A voltage control oscillator 3 changes an oscillating frequency based on the DC voltage VC. On the other hand, a rotating number control circuit 7 outputs a control signal in accordance with a frequency difference between the frequency signal of a frequency generator 11 and the frequency signal of the voltage control oscillator 3 to a motor driving circuit 12 through a gain regulator 13. In this case, the gain of the gain regulator 13 is changed by the DC voltage VC from the phase comparator 1. According to this method, a rotating number control characteristic, having the optimum gain for the rotating speed of a motor 9, may be obtained at all times. |
