Patent ID: 7024608
Filing Date: 2006-04-04
Classification: H03F,H04L

Abstract:
1. A transmitter in which a nonlinear distortion is compensated, the nonlinear distortion being caused by amplifying a modulated signal obtained by modulating a baseband signal to have a radio frequency band, comprising: a quadrature demodulator which outputs a quadrature demodulated signal obtained by demodulating the modulated signal; a linear distortion compensation coefficient calculation unit for calculating and outputting a linear distortion compensation coefficient for compensating for a linear distortion contained in the quadrature demodulated signal; and a linear distortion compensation processing unit for multiplying the baseband signal by data of the linear distortion compensation coefficient and outputting a resultant signal, wherein the linear distortion compensation coefficient calculation unit comprises: a judgment circuit for judging a transmitted symbol according to the quadrature demodulated signal, and reproducing and outputting a data signal and an error signal for each channel; and a linear distortion coefficient calculation circuit for calculating and outputting an in-phase linear distortion compensation coefficient and a quadrature linear distortion compensation coefficient for each channel, respectively, by using the data signal and the error signal for each channel as an input.