Design of an inphase and quadrature phase and amplitude imbalance compensation in quadrature receivers

This paper presents a compensation technique for the amplitude and phase imbalance between the I and the Q components of a quadrature demodulator. The proposed scheme allows the implementation of a fully integrated self-aligned tuner for digital modulation systems such as QAM demodulation and receivers. It is based on a mixed signal analog/digital integrated circuit approach to automatically correct amplitude and phase imbalances resulting from mismatch of integrated circuit components. The approach presented uses the original signal information to create both a control signal for the amplitude and phase correction. It uses digital circuitry to compensate for mismatch errors, by means of an analog feedback mechanism, and perform high accuracy phase and amplitude quadrature correction.