Patent ID: 6384677
Filing Date: 2002-05-07
Classification: H04L

Abstract:
A power amplifier circuit having a negative feedback circuit for a transmitter, comprising:an input terminal for inputting an I-component test signal for an I-component baseband signal and a Q-component test signal for a Q-component baseband signal; an adder coupled to said input terminal for adding said I-component test signal and an I-component baseband feedback signal to generate an I-component summing signal, and adding said Q-component test signal and a Q-component baseband feedback signal to generate a Q-component summing signal; an oscillator for generating a carrier signal; a modulator for orthogonally modulating said carrier signal with said I-component summing signal and said Q-component summing signal; an amplifying circuit coupled to said modulator for amplifying the orthogonally modulated signal; a demodulating circuit coupled to said amplifying circuit for orthogonally demodulating said orthogonally modulated signal by using a part of an output of said amplifying circuit and said carrier signal to output said I-component baseband feedback signal and said Q-component baseband feedback signal; a phase control circuit for generating a phase control signal, to which said I-component and Q-component test signals and one of said I-component and Q-component summing signals are applied; a phase shifter coupled to said demodulating circuit, for changing the phase of said carrier signal outputted for said oscillator in accordance with said phase control signal; and said phase control circuit controlling said phase shifter so that the phase of said carrier signal meets a predetermined condition.