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Document Type:Latin Dissertation
Language of Document:English
Record Number:53048
Doc. No:TL23002
Call number:‭3298472‬
Main Entry:Asif Mohammad
Title & Author:Simple and efficient solutions to the problems associated with acoustic echo cancellationAsif Mohammad
College:University of Missouri - Rolla
Date:2007
Degree:Ph.D.
student score:2007
Page No:68
Abstract:This dissertation is a collection of papers that addresses several important problems associated with acoustic/line echo cancellation (AEC/LEC), specifically double-talk and echo-path change detection. A double-talk detector is used to freeze AEC filter's adaptation during periods of near-end speech. This dissertation presents three different novel double-talk detection schemes. Simulations demonstrate the efficiency of the proposed algorithms. The novel normalized cross-correlation based double-talk detector proposed in Section 3, outperforms the best existing algorithms and is computationally of the order of magnitude simpler. Next, this novel double-talk detector is extended to the frequency domain adaptive algorithms and the proposed technique is also generalized for the multi-channel case. Echo-path variations in acoustic case are common. In general, a detector's increased sensitivity towards double-talk also increases its probability of falsely declaring echo-path changes as double-talk. This adversely affects the performance of the acoustic echo canceller (AEC) as the filter coefficients are frozen precisely when they should be adapting. To remedy this, an efficient explicit echo-path change (EPC) statistic is derived to help differentiate between echo-path variations and double-talk. The combination of the new double-talk and echo-path change statistics yield an effective low-complexity solution to the AEC adaptation control problem. The key to a good two-path method performance lies in the definitions of the download tests. A novel download test is also proposed that improves the overall performance of the system.
Subject:Applied sciences; Double-talk; Echo cancellation; Echo path change; Echo return loss enhancement; Two-path; Electrical engineering; 0544:Electrical engineering
Added Entry:S. L. Grant
Added Entry:University of Missouri - Rolla