Publication IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer SciencesVol.E89-ANo.2pp.469-478 Publication Date: 2006/02/01 Online ISSN: 1745-1337 DOI: 10.1093/ietfec/e89-a.2.469 Print ISSN: 0916-8508 Type of Manuscript: PAPER Category: Digital Signal Processing Keyword: transient analysis, complex-domain, adaptive filter, adaptive threshold, digital QAM system,
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Summary: The paper presents an adaptive algorithm named adaptive threshold nonlinear algorithm for use in adaptive filters in the complex-number domain (c-ATNA) in applications to digital QAM systems. Although the c-ATNA is very simple to implement, it makes adaptive filters highly robust against impulse noise and at the same time it ensures filter convergence as fast as that of the well-known LMS algorithm. Analysis is developed to derive a set of difference equations for calculating transient behavior as well as steady-state performance. Experiment with simulations and theoretical calculations for some examples of filter convergence in the presence of Contaminated Gaussian Noise demonstrates that the c-ATNA is effective in combating impulse noise. Good agreement between simulated and theoretical convergence proves the validity of the analysis.