| 摘要 |
PURPOSE:To surely receive traffic information, etc., by revising a frequency band during reception into a special frequency band for a prescribed time and holding the level of the reception signal to a specific frequency band when the level is a prescribed value or over. CONSTITUTION:A microcomputer 9 outputs a 10ms muting control signal to a PLL circuit 8 at an interval of 60sec to revise a reception data of the PLL circuit 8 thereby receiving a highway radio broadcast during the period only. A DC voltage proportional to the electric field of the received wave is extracted from an intermediate frequency amplifier circuit 4 and inputted to a comparator 5, a vehicle during driving approaches a radio sending point and reaches an excellent receiving state, the DC voltage is larger than the set voltage to the comparator 5, and the microcomputer 9 receiving the signal is operated to revise the reception data of a broadcast wave A into the reception data of the highway radio broadcast.
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