| 摘要 |
PURPOSE:To obtain means for correctly detecting the synchronization with a reference signal irrespective of the rotating speed of a motor by setting the timing of a reference signal with a clock constant to constant irrespective of the frequency of the reference signal. CONSTITUTION:A sawtooth wave generator 6 outputs a sawtooth wave H in response to a signal G converted from the rotating speed of a motor into a frequency. A peak holding circuit 7 holds the peak voltage of the wave H, and outputs it to a comparator 9 through a divider 8. The comparator 9 compares the wave H with the output J of the divider 8, and outputs a signal K. A monostable multivibrator 10 converts the signal K into a signal L having the prescribed width W and inputs to the clock input terminal CK of a shift register 11. On the other hand, a motor reference signal F is input to the data input tarminal D of the register 11. An AND gate 12 outputs a synchronization detection signal when the outputs OUT1-OUTN of the registers 11 are all ''H''. |
