| 摘要 |
PURPOSE:To adjust optionally the band width by deviating the 1st and 2nd local oscillating frequencies so as to shift the center frequency of the 1st and 2nd intermediate frequency signal from the center frequency of the 1st and 2nd filters. CONSTITUTION:The center frequency of the 1st intermediate frequency outputted from the 1st frequency converter 21 is shifted higher or lower by an optional frequency from the center frequency of the 1st filter 22 in either direction. The center frequency of the 2nd intermediate frequency signal outputted from the 2nd frequency converter 23 is shifted by an optional frequency from the center frequency of the 2nd filter 24 in the other direction. Thus, the band width of the signal outputted corresponding to the quantity of frequency shift of the 1st and 2nd intermediate frequency signal is changed and the band width as the filter is varied optionally.
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