Convergence improvement of the LMS adaptive noise canceller using low distortion filter banks

Abstract

This paper presents a subband least mean square LMS noise canceller with improved convergence behaviour. This improvement is achieved by modifying and optimizing an existing multirate filter bank that is used to improve the performance of full-band LMS adaptive filters. The optimized oversampled subband noise canceller offers a simplified structure that without employing cross-filters or gap filter banks reduces the total input/output distortion in speech signals. Issues of increasing convergence speed and decreasing the residual noise at the system output are addressed. Performances under white and colored environments are evaluated experimentally in terms of mean square error MSE performance. Compared to an equivalent oversampled scheme, fast initial convergence and better noise reduction performance can be obtained with this approach.