Compensation of Component Mismatch in RF Receivers using Digital Techniques

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

Keywords

lowIF 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 filters 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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