標題: 利用快速相等 NLMS 作分頻回音消除
Acoustic fast equivalent NLMS echo cancellation in subband
作者: 吳遠全
Wu, Une Chung
謝世福
S.F. Hsieh
電信工程研究所
關鍵字: 回音;重疊;陷波濾波器;分頻;多相法;echo;aliasing;notch filter;subband;polyphase
公開日期: 1997
摘要: 摘要: 由於適應性回音消除器的係數通常高達幾千個, 因此造成收
斂速度慢和運算複雜度高的問題. 本篇論文提出一個快速相等 NLMS 的演
算法, 它和 NLMS 有相似的收斂性但其運算複雜度較低. 對語音信號輸
入, 提出另一個演算法 DFENLMS 來改善 FENLMS 的收斂性.分頻適應性濾
波可以降低運算複雜度並增加收斂速度. 然而分頻濾波會有不可避免的重
疊問題, 因而造成分頻回音消除的殘餘回音信號上會有一個尖端成份. 我
們用陷波濾波器來消除這個尖端成份並且設計不同的陷波濾波器. 我們分
析了不同的陷波濾波器對系統表現和近端語音的影響. 最後我們提供能減
少乘法器的多項法來實現濾波器組和陷波濾波器.
Abstract: Thousands of tap weights of an adaptive FIR echo
canceller usually results in slow convergence speed and high
computational complexity. In thisthesis, a fast equivalent NLMS
(FENLMS) algorithm is proposed which has lower computational
complexity and similar convergence characteristic as compared
tothe NLMS algorithm. For speech signal, another decorrelation
FENLMS (DFENLMS) algorithm is proposed to improve the
performance of the FENLMS algorithm.Adaptive filtering in
subband can reduce the computational complexity and increases
the convergence speed. Howerer, aliasing is an unavoidable
problemin subband filtering, and a peak component will appear in
the residual echo signal. We use notch filters to cancel this
peak component and different notch filters are designed.
Analysis of differnet notch filters on system performanceand
andnear-end speech are given. Finally, the polyphase
implementations of filterbanksand notch filters are given to
reduce the number of multipliers.
URI: http://140.113.39.130/cdrfb3/record/nctu/#NT860435008
http://hdl.handle.net/11536/63027
顯示於類別:畢業論文