| 摘要 |
A system for carrying out automatic fine tuning detection comprising a generating section for generating a video intermediate frequency signal from a radio wave, a filtering section connected to the generating section for filtering the video intermediate frequency signal supplied from the generating section, the filtering section having low and high frequency regions having different gains from each other, a subtracting section connected to both the generating section and filtering section for subtracting an output signal of the filtering section from the video intermediate frequency signal supplied by the generating section, an extracting section connected to the filtering section for fetching the output signal of the filtering section and subsequent extraction of a video carrier wave signal component from the output signal and a multiplying section connected to the subtracting section, the extracting section and the generating section for multiplying an output signal of the subtracting section by an output signal of the extracting section and subsequent conversion into a voltage signal to be fed back to the generating section to thereby control a frequency of the video intermediate frequency signal at a predetermined value.
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