Radio receiver and intermediate frequency selection method

A radio receiver comprising:

• an oscillator that has a variable oscillation frequency;
• a quadrature demodulator that includes a frequency mixer and generates an intermediate frequency signal having an intermediate frequency lower than the frequency of a radio frequency signal, the frequency mixer mixing the radio frequency signal with an oscillation signal outputted from the oscillator;
• an analog filter that bandlimits the intermediate frequency signal;
• an analog-to-digital converter that receives an intermediate frequency signal inputted through the analog filter and converts the received intermediate frequency signal to a digital signal;
• a received signal processing section that generates a demodulated signal from the intermediate frequency signal converted to the digital signal;
• and
• a mode control section that switches the operating mode of the quadrature demodulator between a zero intermediate frequency mode and a low intermediate frequency mode in accordance with radio wave reception conditions, the zero intermediate frequency mode providing the intermediate frequency signal having a zero intermediate frequency, the low intermediate frequency mode providing the intermediate frequency signal having a low intermediate frequency higher than the zero intermediate frequency;