POWER AMPLIFIER WITH PRE-DISTORTION CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a power amplifier with a pre-distortion circuit, which can be operated with high efficiency and obtain a large amount of distortion suppression even around the saturation output power of the power amplifier. SOLUTION: A peak factor detector 122 outputs the PAR (Peak Average Ratio) of an input signal. A second level detector 119 detects the instantaneous electric power and average power of an output signal from the power amplifier 117. A second control circuit 120 obtains a reference power B on the basis of the PAR detected by the peak factor detector 122 and controls a variable phase shifter 112 and a variable attenuator 113 on the basis of an optimum condition so as to maximize the amount of distortion suppression when the average output power of the power amplifier 117 is equal to or larger than the reference power B. COPYRIGHT: (C)2004,JPO&NCIPI