Patent ID: 6693956
Filing Date: 2004-02-17
Classification: H03F,H04L

Abstract:
A power amplifier having a negative feedback circuit for a transmitter, comprising:an input terminal for inputting an I-component baseband signal and a Q-component baseband signal; an adder, coupled with said input terminal, for adding said I-component baseband signal to an I-component baseband feedback signal to produce an I-component adding signal and adding said Q-component baseband signal to a Q-component baseband feedback signal to produce a Q-component adding signal; an oscillator for generating a carrier signal; a modulator for orthogonally modulating said carrier signal by said I-component adding signal and said Q-component adding signal; an amplifier circuit, coupled with said modulator, for amplifying said modulator signal; a demodulator circuit, coupled with said amplifier, for orthogonally demodulating part of an output of said amplifying circuit and said carrier signal and outputting said I-component baseband feedback signal and a Q-component baseband feedback signal; and a phase controller, coupled with said input means, for comparing a phase of a selected one of said I-component baseband signal and said Q-component baseband signal with a phase of said adding signal corresponding to said selected component baseband signal for detecting if a phase shift exists, wherein said phase controller adjusts the phase of said carrier signal so that said phase shift can be made smaller, when said phase shift exists.