The Cancellation of Acoustic Echo in Room by using IIR Filtering Response
Date Issued
2005
Date
2005
Author(s)
Jiang, Yu-Pei
DOI
zh-TW
Abstract
ABSTRACT
Upon the digital signal processing and adaptively active control, this study adopts the (IIR) infinite impulse response digital filter as the systematic structure which combines with the (NLMS) normalized least-mean-square algorithm so as to carry on an optimize operation. To set up the acoustic-echo cancellation system for this study, the combination of the LabVIEW program and A/D-D/A converter data acquisitive equipment with personal computer is used as the required platform.
For the experiment of the acoustic-echo cancellation, an enclosure with highly reflective walls is used as the experimental site, and the selected input signals both of pure-tones and random. The system performances are identified by comparing the methods to set up the parameter of system, its operation performance and their influence on the effectiveness of echo cancellation for various frequencies.
Experimental results show that the ERLE by 20 to 50 decibels for various frequencies form low to high pure-tone sounds are reached. The reductions of echo power spectrum by more than 60 decibels are reached. As regards to the case of randomly acoustic echo, either the ERLE by 2 to 10 dB or the reduction of centre frequency by 3 to 15 dB is achieved. Moreover, for the case of narrow-band acoustic echo, either the ERLE by 13 to 18 dB or the reduction of centre frequency by 10 to 17 dB is achieved.
Subjects
適應性主動控制
無限濾波響應
IIR
adaptively active control
Type
thesis
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