| 摘要 |
A variable directivity antenna (2) has directivity direction variable stepwise along the circumference of a circle centered about it. A tuner (8) selects a desired one from high frequency signals received at the antenna (2). The tuner (8) detects the level of the received signal and supplies it to a control unit (10). The control unit (10) searches for reception signal levels, equal to or higher than a threshold level, of the received signal received in antenna states in which the directivity of the antenna (2) is placed in different ones of directivity directions, and detects a signal-to-noise ratio of the signal received from directions adjacent to each of the searched directivity directions corresponding to the searched signal levels. The control unit (10) employs the searched directivity direction for the highest signal-to-noise ratio as the direction to which the antenna (2) is directed to receive the signal.
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