| 摘要 |
PROBLEM TO BE SOLVED: To achieve low distortion and high efficiency over a wide range of load impedance without using an isolator, and to detect the detection voltage of vector sum of a traveling wave signal from a balanced power amplifier and a reflection wave signal from a load without using a directional coupler. SOLUTION: The RF power amplifier is constituted of a balanced power amplifier system including first phase shifters 250a, b, a first RF power amplifier 60a, a second RF power amplifier 60b, second phase shifters 280a, b, and a power coupler 290. Transmission power Pout is detected by a first power level detector 200a connected to the output of the first RF power amplifier, a second power level detector 200b connected to the output of the second RF power amplifier, and an adder 210. A level control signal Vapc from a level control circuit 220 controls transmission power in response to a target transmission power level signal Vramp and the detection signal Vdet of the adder. COPYRIGHT: (C)2008,JPO&INPIT
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