| 摘要 |
PROBLEM TO BE SOLVED: To correctly retrieve only an analog system radio broadcast wave in a radio broadcasting receiver which is not provided with any circuit which detects a digital system radio broadcast wave. SOLUTION: An FM detection circuit 14 detects an analog system radio broadcast wave. A noise amplifier 3 amplifies noise components higher than those of a voice band included in a detection signal to be output from the FM detection circuit 14. A microcomputer 4 commands a local oscillation frequency to a local oscillator 7, and when an SD signal input from an FM demodulating part 10 is an H level, and an S meter signal is a decision value or more, IF count is commanded to an IF counter 11a. When an IF count value is in a proper range, a noise detection signal is input from the noise amplifier 3, and when it is a predetermined noise decision value or less, it is decided to be an analog system radio broadcast wave, and seek is stopped. COPYRIGHT: (C)2008,JPO&INPIT
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