| 摘要 |
PURPOSE:To select an antenna with high received electric field intensity at all times by starting searching operation in response to a sudden decrease in received electric field intensity and searching for and selecting an antenna which has a large received electric field. CONSTITUTION:When the intensity of the received electric field varies abruptly and the output of a level detecting circuit 7a drops, a monostable multivibrator 14 operates and a pulse generating circuit 16 is triggered. This pulse generating circuit 16 searches for an antenna 1 or 2 which has large received electric field intensity according to the trigger signal. An antenna switching driving circuit 56 switches an antenna switching circuit 3 according to the level comparison result of a level comparing circuit 55 to select an antenna having a high reception level automatically.
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