| 摘要 |
PURPOSE:To discriminate whether a motor rotates at a target speed or not in a short time by correcting the variation in the counted output in response to a phase difference between a reference signal and a speed detecting pulse in response to the variation in the actual phase difference. CONSTITUTION:A reference signal fref and a speed detecting pulse f1 from a speed detector 1 are taken at a timing by time division pulses P1, P2, differentiated by a differentiator 3, and output as clock pulses CP1. CP2. The pulses CP1, CP2 are applied to a counter 4 to obtain a phase difference CD between the reference signal fref and the pulse f1. When the counted data CD is negative in the polarity, the complement of the data CD is obtained, 1 is added to the complement by an adder 7, and the sum is output as a counted data OD. When the counted data CD is positive in the polarity, it is output as the data OD. |
