A Step Size Control Method Improving Estimation Speed in Double Talk Term

Takuto YOSHIOKA  Kana YAMASAKI  Takuya SAWADA  Kensaku FUJII  Mitsuji MUNEYASU  Masakazu MORIMOTO  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E96-A   No.7   pp.1543-1551
Publication Date: 2013/07/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E96.A.1543
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Digital Signal Processing
echo canceller,  double talk,  step size control,  block length control,  target error level control,  

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In this paper, we propose a step size control method capable of quickly canceling acoustic echo even when double talk continues from the echo path change. This method controls the step size by substituting the norm of the difference vector between the coefficient vectors of a main adaptive filter (Main-ADF) and a sub-adaptive filter (Sub-ADF) for the estimation error provided by the former. Actually, the number of taps of Sub-ADF is limited to a quarter of that of Main-ADF, and the larger step size than that applied to Main-ADF is given to Sub-ADF; accordingly the norm of the difference vector quickly approximates to the estimation error. The estimation speed can be improved by utilizing the norm of the difference vector for the step size control in Main-ADF. We show using speech signals that in single talk the proposed method can provide almost the same estimation speed as the method whose step size is fixed at the optimum one and verify that even in double talk the estimation error, quickly decreases.