| 摘要 |
PROBLEM TO BE SOLVED: To provide a frequency discrimination circuit which can be effectively applied to a sampling frequency conversion device. SOLUTION: The frequency discrimination circuit 20 for discriminating the frequency of an input clock CKin having any one of a plurality of predetermined frequencies is provided with a frequency measurement unit 22 for counting reference clocks RefCLK in each of N (N is a natural number) periods of an input clock CKin and outputting a count value; a range judgment unit 23 for specifying to which frequency range out of a plurality of frequency ranges made to respectively correspond to a plurality of frequencies the count value belongs; and a continuous coincidence judgment unit 26 for judging whether the frequency range specified by the range judgment unit 23 is continuously the same only by the prescribed number of times. COPYRIGHT: (C)2009,JPO&INPIT
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