Patent ID: 8095095

Claim:
A band switch control apparatus for an intermediate frequency filter comprising: an adjacent interference signal detecting unit configured to detect an adjacent interference signal superimposed on a reception signal having a frequency tuned to a desired frequency, the adjacent interference signal having a frequency adjacent to the desired frequency; a modulation-degree detecting unit configured to detect a modulation degree of the reception signal; a bandwidth selecting unit configured to select a pass bandwidth of the in frequency filter corresponding to an amplitude of the adjacent interference signal; and a band-narrowing suppression control unit configured to select a lower limit value of the pass bandwidth of the intermediate frequency filter corresponding to the demodulation degree, the intermediate frequency filter being configured to pass, with a variable pass bandwidth, an intermediate frequency signal obtained by frequency converting the reception signal, and change 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 lower limit value thereby increasing the pass bandwidth to the lower limit value.