| 摘要 |
PURPOSE:To permit stabilized PLL speed control even when a non-stabilized power source is employed, by a method wherein the control gain of a control system, controlling an average voltage supplied to a DC motor, is varied in accordance with a power source voltage. CONSTITUTION:A phase comparator 9 supplies a loop filter 10 with a phase difference signal between a reference frequency signal, outputted from a processor 8, and the output signal of a frequency generator 7. An adder 11 adds the output signal of the loop filter 10 to a signal, in which the output signal of the frequency generator 7 is converted into an analog voltage. A comparator 12 compares a triangular wave signal, outputted from a triangular wave generator 13, with the output signal of the adder 11 and drives a transistor 5 by the result of the comparation. The processor 8 outputs a control signal for determining a control gain in accordance with the output voltage of a power source circuit into the adder 11. |
