| 摘要 |
PURPOSE:To prevent occurrence of out of locking in the occurrence of a phase jump of an input clock by detecting the phase jump of the input clock so as to set a frequency division circuit for feedback specifically. CONSTITUTION:A phase jump detection circuit 4 monitors a phase difference between an input clock 5 and a feedback clock 7, outputs a set signal 8 to a frequency divider circuit 3 for feedback of a PLL circuit 2 if any phase jump takes place in the clock 5. Then the circuit 3 is set so that the phase of the clock 7 is in matching with the phase of the clock 5 and the occurrence of out of locking in the PLL circuit 2 in the occurrence of a phase jump in the input clock is prevented. |
