| 摘要 |
PROBLEM TO BE SOLVED: To provide a motor controller which can suppress the occurrence of audible noise and electromagnetic noise with inexpensive constitution. SOLUTION: A motor M is controlled based on the PWM control signal of specified frequency within an audible frequency band. At this time, generated audible noise is attenuated by the noise attenuating waves outputted from a noise attenuating wave outputting circuit 40. The noise attenuating wave output circuit 40 is equipped with a photocoupler 41 which detects the phase of the PWM control signal and outputs a signal of the same phase as the detected phase, an amplifier 42 which inverts the phase of the output signal of the photocoupler 41, and a piezoelectric buzzer 43 which generates acoustic waves (noise attenuating waves), based on the output signal of the amplifier 42. |
