| 摘要 |
PURPOSE:to improve the operability and to simplify a device by selecting a transmission frequency, which has the highest reception strength or has a level higher than a prescribed value, from plural transmission frequencies of traffic information transmission on a basis of the level of the reception strength by one operation of one selecting switch. CONSTITUTION:When a traffic information private switch 41 is operated, a successive sending circuit 39 supplies plural local oscillation frequency information stored in a traffic information frequency memory 45 to a local oscillating part 25 successively. The local oscillating part 25 supplies signals having frequencies corresponding to supplied local oscillation frequency information to determine a reception frequency. Traffic information transmitted with this frequency is received by an antenna 11 and is amplified by a high frequency amplifying part 13 and is selected by a frequency converting part 15 and is amplified as an intermediate frequency signal by an intermediate frequency amplifying part 17. The intermediate frequency signal amplified by the intermediate frequency amplifying part 17 is converted to a DC level signal proportional to the strength of this intermediate frequency signal by a signal level detecting part 37, and the converted DC level signal is outputted to a maximum value detecting part 43.
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