| 摘要 |
PROBLEM TO BE SOLVED: To increase or decrease gains depending on impedance variations of an antenna and achieve switching to the antenna hardly affected by human body interference and the like.SOLUTION: A plurality of antennae (ANT6-1 and 6-2) are switchably provided in a portable terminal device (2), and gains of amplifiers (10 and AGCAMP32) are increased or decreased depending on impedance variations of the antenna (ANT6-1 or 6-2) during operations. In a control part (12), an antenna state is determined by a difference between a set value of the reference amplifier and a set value of the amplifier during the operations. The antennae are switched on the basis of the result of this determination. |
