| 摘要 |
PURPOSE:To automatically regulate a bias voltage by setting the bias voltage so that the displacement from a reference voltage of a phase servo error voltage becomes 0 or within a limited value, thereby following the bias voltage to a torque load. CONSTITUTION:A digital trap 12 output a trapezoidal digital signal to gradually rise a voltage from the fall of a frequency signal FG through a variable delay circuit 20, and a latch circuit 13 latches the output at the rise of the signal FG. On the other hand, a digital phase comparator 15 outputs a phase difference signal between the frequency signal FG and a reference signal REF, and a latch circuit 17 latches the output. A mixer amplifier 15 adds the outputs of the latch circuits 15, 17 and supplies it to a motor M. A comparator 21 compares the output of the latch circuit 17 with a reference value RO to control the delay amount of the circuit 20. |
