Patent ID: 6304751
Filing Date: 2001-10-16
Classification: H04B

Abstract:
A method for correcting for output phase and magnitude imbalances between digitized in-phase and quadrature outputs of an image rejection mixer comprising the steps of:measuring a magnitude imbalance between the in-phase and quadrature outputs of the image rejection mixer;selecting a stored coefficient in response to said step of measuring;setting a zero of a finite impulse response filter with the selected coefficient; andpassing the in-phase output of the image rejection mixer through the finite impulse response filter to attenuate an image in a complex signal comprising in-phase and quadrature components,wherein said step of passing the in-phase output through the finite impulse response filter comprises the substeps of:passing the in-phase output through a delay element;adjusting the gain of the in-phase output to a level determined by the selected coefficient; andadding an output of the variable gain stage to the in-phase output of the image rejection mixer.