| 摘要 |
PROBLEM TO BE SOLVED: To suppress the excessive temperature rise of an antenna tuner at an antenna tuner side without controlling a transmitter side.SOLUTION: A protection circuit of an antenna tuner 2 configured such that variable impedance circuits 6 and 7 each having a capacitor and a coil are interposed and connected between a transmitter 1 and an antenna 3, and impedance between the transmitter and the antenna is matched includes: temperature detection means 84 for detecting the internal temperature of the antenna tuner; output detection means 85 for detecting the size of a transmission output to be output from the transmitter; and protection means 9, 21, 23, 86 and 87 for, when the internal temperature of the antenna tuner detected by the temperature detection means exceeds a predetermined threshold, and the transmission output detected by the output detection means is equal to or less than a predetermined threshold, controlling the transmission output not to be supplied to the coil. |
