| 摘要 |
<P>PROBLEM TO BE SOLVED: To control changes in the receiving characteristics of an antenna so that always optimum receiving performance is maintained independently of variation in receiving environments such as a state whether a receiving apparatus is moved or not. <P>SOLUTION: When receiving quality is smaller than a threshold and smaller than preceding receiving quality during the movement of the receiving apparatus (A5: YES), the receiving characteristic of the antenna is switched. In a still state (A5: NO) on the other hand, when the receiving quality is smaller than the threshold and smaller than the preceding receiving quality and the preceding receiving quality is larger than the threshold (1) or when the receiving quality is smaller than the threshold and smaller than the preceding receiving quality, the preceding receiving quality is smaller than the threshold and the receiving characteristic of the antenna is switched in the preceding time (2), the receiving characteristic of the antenna is switched. <P>COPYRIGHT: (C)2007,JPO&INPIT |
