| 摘要 |
An antenna switching apparatus which detects an antenna of good reception with high precision and suppresses control errors in antenna switching. A comparator compares a noise component obtained from a selected antenna with a threshold for noise detection. When noise detection occurs a predetermined number of times within a predetermined time, an antenna switching control unit outputs an antenna switching control signal to switch to another antenna. If all antennas are switched within a predetermined time, a noise switching count analyzing unit outputs a sensitivity control signal, deciding that the threshold should be changed. A noise detection sensitivity setting unit, when supplied with the sensitivity control signal within a predetermined time, increases the threshold to lower the noise detection sensitivity of the comparator. When the predetermined time elapses without the sensitivity control signal being supplied, the noise detection sensitivity setting unit decreases the threshold to lower the noise detection sensitivity of the comparator. The noise detection sensitivity is thus varied and adjusted to the actual reception quality, whereby an antenna of good reception is detected with high precision and control errors in antenna switching are suppressed.
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