tailieunhanh - Báo cáo hóa học: " Hindawi Publishing Corporation EURASIP Journal on "

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Hindawi Publishing Corporation EURASIP Journal on | Hindawi Publishing Corporation EURASIP Journal on Audio Speech and Music Processing Volume 2007 Article ID96101 5 pages doi 2007 96101 Research Article Wavelet-Based MPNLMS Adaptive Algorithm for Network Echo Cancellation Hongyang Deng1 and Milos Doroslovacki2 1 Freescale Semiconductor 7700 W Parmer Lane Austin TX 78729 USA 2 Department of Electrical and Computer Engineering The George Washington University 801 22nd Street . Washington DC 20052 USA Received 30 June 2006 Revised 23 December 2006 Accepted 24 January 2007 Recommended by Patrick A. Naylor The M-law proportionate normalized least mean square MPNLMS algorithm has been proposed recently to solve the slow convergence problem of the proportionate normalized least mean square PNLMS algorithm after its initial fast converging period. But for the color input it may become slow in the case of the big eigenvalue spread of the input signal s autocorrelation matrix. In this paper we use the wavelet transform to whiten the input signal. Due to the good time-frequency localization property of the wavelet transform a sparse impulse response in the time domain is also sparse in the wavelet domain. By applying the MPNLMS technique in the wavelet domain fast convergence for the color input is observed. Furthermore we show that some nonsparse impulse responses may become sparse in the wavelet domain. This motivates the usage of the wavelet-based MPNLMS algorithm. Advantages of this approach are documented. Copyright 2007 H. Deng and M. Doroslovacki. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. INTRODUCTION With the development of packet-switching networks and wireless networks the introduced delay of the echo path increases dramatically thus entailing a longer adaptive filter. It is well known that long adaptive filter will cause two problems .