A Hilbert transform and sine curve fitting-based method for estimating gain and phase errors in quadrature mixing structure

Abstract

To eliminate the influence of gain and phase imbalance between in-phase (I) and quadrature (Q) signals on receiver performance featuring the quadrature mixing, a method of estimating the imbalance parameters of I/Q signals is proposed based on the quadrature relation of I/Q channels in time domain. The method uses the output signal of channel I after Hilbert transform as the ideal reference signal to calculate the gain and phase error parameters of channel Q by sine curve fitting (SCF) and least square method (LSM). Experimental tests show that the proposed algorithm can estimate the I/Q imbalance parameters effectively and accurately.