| 摘要 |
PROBLEM TO BE SOLVED: To generate a multiplied output, corresponding to the 2n-fold frequency of an input signal only through a digital circuit in a frequency multiplier circuit. SOLUTION: On the basis of a reference clock, for example, the cycle of an input signal A is counted by a counter circuit 13 of a cycle-measuring circuit part 11 and that count value C is latched by a latch circuit 14. Also, low-order 5-bit data Db of these latch data D and a count value E of a counter circuit 51 for performing count operation with a multiplied output from a counter circuit 43 as a clock are compared by a level comparator 21. According to the compared result, a data selector 31 is controlled, and the frequency-dividing ratio of the counter circuit 43 inside a frequency divider circuit 41 for dividing the frequency of the reference clock is switched over.
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