Compensation of Component Mismatch in RF Receivers using Digital Techniques

E.E. Seagraves and B.L. Walcott (USA)

Keywords

low-IF receiver, component mismatch, image rejection

Abstract

The quadrature IF receiver topology is utilized in direct conversion and low-IF receivers. In theory the quadrature IF topology eliminates the need for the image ļ¬lters re quired by the heterodyne topology. In practice mismatch in analog components between the I and Q signal paths al lows leakage of image energy into the desired signals band. This leakage limits the performance of the quadrature IF receiver. This paper utilizes a two-input two-output LTI equivalent model of the mismatched receiver. Based on the equivalent model an architecture to suppress the image leakage caused by the analog mismatch in the I and Q sig nal paths is proposed. The model-based image suppression is validated through simulation and shown to provide good performance.

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