Patent ID: 6989713
Filing Date: 2006-01-24
Classification: H03F

Abstract:
1. A low-distortion power amplifier comprising: a combining circuit for combining an input signal with another signal; a power amplifier for receiving an output signal of the combining circuit; a divider for branching an output signal of the power amplifier into plural branched signals; a distortion extraction circuit for extracting a distortion signal from one of the branched signals; at least two filter circuits for separating the distortion signal into distortion signals having different frequencies; at least two amplitude frequency characteristic adjustment circuits for adjusting amplitude frequency characteristics of the distortion signals that are output from the respective filter circuits; and at least two vector adjustment circuits for varying amplitudes and phases of distortion signals that are output from the respective filter circuits, wherein a signal obtained by combining together output signals of the vector adjustment circuits is input to the combining circuit as said another signal and the other branched signal is output from the low-distortion power amplifier.