| 摘要 |
PROBLEM TO BE SOLVED: To effectively suppress the higher harmonic components of an output signal even when an input signal frequency varies. SOLUTION: This frequency multiplication circuit is provided with a plurality of filters 2 and 3 connected so that the same input signal Sin can be input in parallel, wherein their cut-off frequency or band pass frequency is different; a plurality of frequency multiplication parts 4 and 5 connected to the plurality of filters 2 and 3 for multiplying the frequency; a plurality of band-pass filters 6 and 7, respectively connected to the plurality of frequency multiplying parts 4 and 5, and equipped with band-pass filters different from each other, according to the output of the corresponding frequency multiplying parts; a signal detection part (included in full-wave rectifier circuits 4 and 5) for detecting a plurality of signal intensity, by a plurality of paths 1 and 2 from the output of the filter 2 (3) to the output of the band-pass filter 6 (7) and a selection part (voltage comparison circuit 8 and a selection circuit 9) for selecting the output of the band-pass filter (6, 7) of the path, in which the detection level of the plurality of signal intensity detected by the signal detecting part is the highest. COPYRIGHT: (C)2008,JPO&INPIT
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