Radio broadcast receiver, automatic tuning device for radio broadcast and method for receiving radio broadcast

An automatic tuning device of analog broadcasting for searching a broadcast frequency corresponding to a reception signal level of a 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, wherein the reception signal is outputted from a radio broadcast receiver having a frequency conversion circuit and a detection circuit, wherein the frequency conversion circuit receives an analog radio broadcast wave and outputs the reception signal having an intermediate frequency, and wherein the detection circuit detects the reception signal of the analog radio broadcast wave and outputs a modulation signal as a detection signal in an audio range, the device comprising:

• a noise amplifier for amplifying a noise component in the detection signal and for outputting a noise detection signal corresponding to a noise amount;
• and
• a controller, 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 controller controls the frequency conversion circuit to output the reception signal, which is converted to have the intermediate frequency from the broadcast frequency,
• the controller 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.

A method for receiving analog radio broadcast comprising:

• receiving an analog radio broadcast wave, converting the analog radio broadcast wave to have an intermediate frequency from a broadcast frequency of the analog radio broadcast wave, and outputting the converted radio broadcast wave as a reception signal having the intermediate frequency;
• detecting the reception signal of the analog radio broadcast wave and outputting a modulation signal as a detection signal in an audio range;
• searching the 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
• amplifying a noise component in the detection signal and 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 searching includes selecting 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.