Patent ID: 8260233

Claim:
An FM receiver comprising: an intermediate signal generation circuit for generating an intermediate signal, a received signal being subjected to frequency conversion for shifting a carrier frequency of an FM signal intended to receive to a predetermined intermediate frequency; a band pass filter for passing the FM signal intended to receive converted to the intermediate signal, a predetermined pass characteristic parameters including a passband width and an attenuation slope being variably settable; a received intensity detection circuit for detecting a received electric field intensity based on the intermediate signal; a modulation degree detection circuit for detecting a modulation degree of the FM signal intended to receive; an adjacent-channel interference detection circuit for detecting an interference of an adjacent-channel signal on the FM signal intended to receive; a bandwidth control circuit for setting the passband width to a basic bandwidth in accordance with an interested reception condition, the bandwidth control circuit being a hard-wired circuit for performing a predetermined control being carried out with respect to the band pass filter in accordance with the interested reception condition composed of a combination of the received electric field intensity, the modulation degree, and an intensity of the interference of the adjacent-channel signal; a storage part for storing a control program in which is stored a control procedure for controlling the attenuation slope in accordance with the intensity and the modulation degree with respect to the band pass filter; and a microcomputer executing the control program and controlling the band pass filter to vary the width of a transition band in accordance with the attenuation slope.