| 摘要 |
PURPOSE:To detect synchronized condition of motor accurately, by counting output signals from a phase comparator during 1/n interval of the period of reference signal. CONSTITUTION:A speed signal fed from a speed detector 5 is shaped through a shaper 6 into a rectangular wave, and the phase thereof is compared through a phase comparator 4 with the phase of a referential signal outputted from a referential signal generating section 3. Output signal from the phase comparator 4 is counted through a counter 15. The reference signal is frequency divided through a 1/3 frequency divider 17 and the output signals therefrom are fed to the clear terminal of the counter 15 and the set terminal of a latch 16. Outputs from the counter 15 are fed through AND gate 18 and NAND gate 19 to the base of a transistor 22 so as to detect synchronous condition of motor. |
