| 摘要 |
A band-switch control apparatus for an intermediate-frequency filter comprising: an adjacent interference-signal detecting unit for detecting an adjacent interference-signal, having a frequency adjacent to the desired frequency, superimposed on a reception signal having a frequency tuned to a desired frequency; a modulation-degree detecting unit for detecting a modulation degree of the reception signal; a bandwidth selecting unit for selecting a pass bandwidth of the intermediate-frequency filter corresponding to the amplitude of the adjacent interference-signal; and a band-narrowing suppression control unit for selecting a lower limit value of the pass bandwidth of the intermediate-frequency filter corresponding to the demodulation degree, the intermediate-frequency filter for passing, with a variable pass bandwidth, an intermediate-frequency signal obtained by frequency converting the reception signal, and changing the pass bandwidth selected by the bandwidth selecting unit to the lower limit value, if the pass bandwidth selected by the bandwidth selecting unit is smaller than the value. |
