A self-calibrating quadrature mixing front-end for SDR

Abstract

A quadrature mixing front-end is well-suited toward software define radio (SDR) applications, due to its low complexity and the inherent flexibility that it affords the radio front-end. Its performance is, however, severely affected by gain and phase mismatches between its two signal paths, as well as the presence of unwanted DC offsets. This paper presents solutions for a self-calibrating quadrature transceiver. Practical implementation results indicate a significant improvement in the image and offset rejection capabilities of such a calibrated transceiver.