| 摘要 |
PURPOSE:To form an optimum feedback loop in response to the characteristic of a rotor by switching a clock frequency of a counter generating a trapezoidal data while decoding data of plural bits from the most significant bit of the counter. CONSTITUTION:The counter 41 starts counting synchronously with a reference signal representing the reference of the phase of the rotor, and the counter 41 uses a clock frequency switching means to decode data of plural bits from the most significant bit of the counter 41 thereby switching the frequency of the clock signal of the counter 41. Thus, the rate of change in the content of the counter 41 varies with the elapsed time. The count of the counter 41 is used as a phase error signal in response to the phase shift in the rotor, the relation between the phase shift of the rotor and the phase error signal is decided to have an optional characteristic. |
