Patent ID: 8913690
Filing Date: 2014-12-16
Classification: H03C,H03F,H04B,H04L

Abstract:
1. An amplifier circuit, comprising: a quadrature modulator that quadrature-modulates an IQ baseband signal; an amplifier that amplifies the quadrature-modulated signal; a distortion compensation section that compensates for distortion to be caused in the amplifier based on first compensation coefficients; a quadrature modulation error compensation section that compensates the IQ baseband signal outputted from the distortion compensation section for a quadrature modulation error; an updating section that updates second compensation coefficients that are used for compensation in the quadrature modulation error compensation section; an error estimation section that estimates an error, which is caused by that the IQ baseband signal outputted from the quadrature modulation error compensation section is quadrature-modulated by the quadrature modulator; and a prediction section that calculates a prediction value of an output of the amplifier after updating of the second compensation coefficients, wherein the updating section updates the second compensation coefficients, based on the error estimated by the estimation section, the error estimation section estimates the error, based on the IQ baseband signal before compensated by the distortion compensation section, and the IQ baseband signal obtained by quadrature demodulation of the output of the amplifier, the prediction section calculates the prediction value, based on the error estimated by the estimation section, and the IQ baseband signal obtained by quadrature demodulation of the output of the amplifier before updating of the second compensation coefficients based on the error estimated by the estimation section, and the distortion compensation section calculates the first compensation coefficient, based on the prediction value.