Patent ID: 8072261

Claim:
A power amplifier for amplifying a modulated signal including an amplitude-modulated component and a phase-modulated component, comprising: a decomposing circuit for decomposing said amplitude-modulated component into two control signals; a mixing circuit for mixing one of the decomposed control signals with said phase-modulated component; an amplifying circuit for amplifying the other of the decomposed control signals; an RF amplifier for amplifying a signal output from said mixing circuit, amplitude-modulating the amplified signal with an output signal from said amplifying circuit, and outputting the amplitude-modulated signal; a signal generating circuit for extracting said amplitude-modulated component of said modulated signal and extracting and outputting the phase-modulated component of said modulated signal, said signal generating circuit including said decomposing circuit; and a first pulse modulator for pulse-modulating one of the decomposed control signals; wherein said mixing circuit comprises a mixer for mixing said phase-modulated component extracted by said signal generating circuit and a rectangular-wave signal output from said first pulse modulator, with each other; said amplifying circuit comprises a second pulse modulator for pulse-modulating the other of the decomposed control signals, a switching amplifier for current-amplifying a rectangular-wave signal output from said second pulse modulator, and a low-pass filter for smoothing an output signal from said switching amplifier; and said RF amplifier amplifies an output signal from said mixer, amplitude-modulates the amplified signal with an output signal from said low-pass filter, and outputs the amplitude-modulated signal.