| 摘要 |
PROBLEM TO BE SOLVED: To compare phase of a reference clock signal with that of a clock signal. SOLUTION: A clock frequency converter of the phase comparator, that detects a phase difference between the phase of a 1st clock signal and a phase of a 2nd clock signal, selects the frequency of the 2nd clock signal to be a frequency of multiples of 2n (n is a natural number) of the 1st clock signal, a 1st sample and hold circuit 6 allows a level of the 2nd clock signal to follow or hold a level of the 1st clock signal. A 2nd sample-hold circuit 7 holds the level of the 2nd clock signal 7 when the 1st sample-hold circuit 6 is in a follow operation, and follows the level of the 2nd clock signal, when the 1st sample- hold circuit 6 is in a holding operation. A selector 8 selects the output of the 1st sample and hold circuit 6 or the 2nd sample-hold circuit 7 in the holding operation and provides an output.
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