| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a constitution of a multiple PLL circuit which suppresses the generation of transitional vibration such as vibration generated by overshoot and slip even if a phase of an input signal is abruptly changed, in the case of a step signal during drive control of a motor in which a frequency of the input signal is changed. <P>SOLUTION: When a phase difference detected by a second phase comparison circuit 24 of a second PLL 21 is beyond a prescribed range, the motor 22 of the second PLL 21 is controlled by a first PLL 11, not via a loop adder 26, and on the other hand, when the phase difference is within the prescribed range, signal routes of the first and second PLLs 11, 12 are switched by a signal route switching part 33 so that the multiple PLL circuit is constituted by connecting the first PLL 11 and the second PLL 21 via the loop adder 26. <P>COPYRIGHT: (C)2011,JPO&INPIT |
