M.A. Thesis:

Study and Simulation of Adaptive Algorithms in Echo Cancellation of an Acoustic Signal for phone call

Abstract: Nowadays, by extension of application of communication system and ocoustic information transmation, echo cancellation in these system has gained significant attention. In exchange of acoustic information, exsitance of echo could lead in transmission untrue information into another side or it couse impossibility of conversation and unclearance of ocoustic message which recived. Different algorithms are used for cancellation of echo from acoustic signal, which have their advantage and disadvantage. Using an adaptive filters is a way of echo cancellation. In these filters because of long impulse response, reduction of complexity of calculation and fast convergence, adaption process were carried out in frequency domain. In this thesis, various adaptive algorithm such as LMS, NLMS, VSLMS, VSNLMS, RLS which can used for echo cancellation were simulated and studied, and in the end MAX-E adaptive algorithm which used in echo cancellation from data [3], were simulated for echo cancellation of acoustic signal. Determination steps of filter factors and calculation leading rate of the algorithm were studied and convergence behaviour the result of simulation were compared with similar methods and determined that used of MAX-E adaption algorithm for echo cancellation of acoustic signal lead in achieving desired result.

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