| 摘要 |
PURPOSE:To ensure a good reception for a car even when travelling in a region of weak electric field, by carrying out a switching reception with use of a whip antenna plus an antenna having plural feeding points. CONSTITUTION:When a car is travelling in the strong/medium electric field regions having a level higher than the threshold level of an FM receiver 16, an antenna switching circuit 15 selects a whip antenna 10 to receive an FM broadcast. If a multipath reception arises under such conditions, a detecting circuit 19 detects a reduction of the field level caused by the antenna 10 or an occurrence of echo distortion. Thus a control circuit 20 is actuated, and thus the antenna 10 is changed to a glass antenna 11 for reception by the circuit 15. |
