| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a phase comparison circuit which can perform a high-speed frequency change, besides has a small size, and further can reduce the spurious response. <P>SOLUTION: The phase comparison circuit is equipped with a distributed frequency divider which generates a fractional-divided signal produced by dividing a clock signal into fractional division based on a control signal from a control circuit, a first integer divider which generates a first integer-divided signal produced by dividing the distributed frequency signal into the integer division, a second integer divider which generates a second integer-divided signal produced by dividing a reference clock signal into the integer-divided process, a first selection circuit which outputs selectively any one of the fractional-divided signal and first integer-divided signal based on a switching signal, a second selection circuit which outputs selectively any one of the fractional-divided signal and second integer-divided signal based on a switching signal output from the control circuit, and a phase comparator which generates a comparison signal for comparing frequency and phase differences between output signals output from the first and second selection circuits, respectively. <P>COPYRIGHT: (C)2007,JPO&INPIT |
