Radio receiver and radio receiving method

A radio receiver comprising:

• one or more antenna to receive radio signals;
• a plurality of filters to selectively output signals in respective reception bands from the radio signals received by the antenna, adjacent reception bands partially overlapping each other;
• a plurality of down converters disposed correspondingly to the filters to conduct down-conversion from radio frequency to intermediate frequency on signals output from respective ones of the filters;
• a plurality of A/D converters disposed correspondingly to the down converters to convert the signals on intermediate frequency output from respective ones of the down converters to digital signals;
• a plurality of FFT units disposed correspondingly to the A/D converters to conduct fast Fourier transform on digital signals generated by respective ones of the A/D converters;
• extracting units which extract signal components of a boundary radio signal spreading across at least two reception bands adjacent to each other from transformed digital signals associated with the at least two reception bands adjacent to each other;
• a combining unit to combine the signal components extracted by the extracting units to restore the boundary radio signal;
• an IFFT unit to conduct inverse fast Fourier transform on the boundary radio signal restored by the combining unit;
• and
• a demodulation unit to demodulate the transformed boundary radio signal,
• wherein
• as regards down converters and FFT units which conduct processing on the at least two reception bands adjacent to each other, a ratio of a down conversion frequency difference between the down converters to a reciprocal of a frame length used in the FFT units is definite.