Patent ID: 8442157
Filing Date: 2013-05-14
Classification: H04L

Abstract:
1. A wireless apparatus comprising: an analog-to-digital converter (A/D) which samples an in-phase signal component and a quadrature signal component from a quadrature-modulated signal of analog form alternately; a digital quadrature demodulation unit which applies digital quadrature demodulation to an output signal of said A/D converter and outputs an in-phase signal and a quadrature signal; and an error detection unit which, based on said in-phase and quadrature signals output from said digital quadrature demodulation unit, detects a time difference error between sample timing of said in-phase signal component and sample timing of said quadrature signal component and an amplifier which amplifies a modulated signal produced by quadrature-modulating a transmit signal; a distortion compensating coefficient computing unit which computes a distortion compensating coefficient so as to reduce a difference between said transmit signal as a reference signal and said in-phase and quadrature signals demodulated by said A/D converter and said digital quadrature demodulation unit from said modulated signal amplified by said amplifier; and a distortion compensating coefficient storage unit whose stored contents are updated by said computed distortion compensating coefficient; and a distortion compensating unit which applies distortion compensation to said transmit signal by using said distortion compensating coefficient.