| 摘要 |
PURPOSE:To make a device compact, by converting a pulse width modulation signal in compliance with a rotating signal pulse outputted from a controller into a clock pulse with a voltage level converter and a voltage control oscillator, and by comparing the clock pulse with the rotating pulse. CONSTITUTION:A controller 33 outputs a PWM (pulse width modulation) signal based on the rotating signal pulse from a rotation detector 31. A voltage level converter 34 integrates this PWM signal and give it to a voltage control oscillator 35. The voltage control oscillator 35 generates a clock pulse as the oscillation frequency is controlled with the DC voltage. A digital frequency servo circuit 37 compares the clock pulse with the rotating signal pulse and gives the output signal, depending on the difference of its cycle to a drive circuit 39 through an integration circuit 38. |
