Patent ID: 7787842

Claim:
A radio broadcast receiver for analog broadcasting, comprising: a frequency conversion circuit for receiving an analog radio broadcast wave and for outputting a reception signal having an intermediate frequency; a detection circuit for detecting the reception signal of the analog radio broadcast wave and for outputting a modulation signal as a detection signal in an audio range; an automatic tuning device for searching a broadcast frequency corresponding to a reception signal level of the reception signal by changing a reception signal frequency of the reception signal, the reception signal level being equal to or larger than a predetermined electric field intensity threshold value; and a noise amplifier for amplifying a noise component in the detection signal and for outputting a noise detection signal corresponding to a noise amount, wherein the noise component corresponds to a digital radio broadcast wave having a frequency adjacent to the broadcast frequency of the analog radio broadcast wave, the automatic tuning device controls the frequency conversion circuit to output the reception signal, which is converted to have the intermediate frequency from the broadcast frequency, the automatic tuning device selects the broadcast frequency of the analog radio broadcast wave when the reception signal level is equal to or larger than the predetermined electric field intensity threshold value and a noise detection signal level of the noise detection signal is equal to or smaller than a predetermined noise determination threshold value, and the predetermined noise determination threshold value is preliminarily set with respect to the digital radio broadcast wave.