| 摘要 |
PROBLEM TO BE SOLVED: To improve a bit error rate in an weak electric field state during an AF search of an FM radio receiver having an RDS receiving function. SOLUTION: The bandwidth WF of a band-pass filter which band-limits an intermediate frequency signal is fixed to a wide bandwidth w<SB>W</SB>in a state of no adjacent-channel interference during the AF search without reference to whether receiving electric field intensity is large or small. Namely, the bandwidth is narrowed during normal reception for a weak electric field even in the absence of adjacent-channel interference to remove weak electric field noise, but widened during the AF search. Thus, the bandwidth is widened in the weak electric field state to improve a bit error rate of the AF search, thereby suitably detecting a PI code. COPYRIGHT: (C)2009,JPO&INPIT
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