| Summary: | 碩士 === 國立臺北科技大學 === 電機工程系研究所 === 99 === Acoustic echo usually arises when sound from a loudspeaker is picked up by the microphone in the same room. In this thesis, two acoustic echo cancellation algorithms are proposed to anticipate the sound signal and cancel it out in order to improve the voice quality on a telephone call. The first one is the variable step size improved proportionate affine projection (VSS-IPAP) algorithm, and the second one is the variable step size improved Gauss-Seidel pseudo proportionate affine projection (VSS-IGSPPAP) algorithm. Four pseudo room space environments are simulated by different sparseness room impulse responses (RIR) in the experiment. The relative system distance (SD) and echo return loss enhancement (ERLE) are often used as the measure criteria to compare different acoustic echo cancellation algorithms. The experimental results show that both proposed algorithms are able to achieve superior performance than the well-known normalized least-mean-square (NLMS) algorithm and other traditional acoustic echo cancellation algorithms. However, like the affine projection (AP) algorithm, the VSS-IPAP algorithm always suffers a large amount of computational load. On the contrary, the proposed VSS-IGSPPAP algorithm not only provides fast convergence speed in different sparseness room impulse response (RIR) situations but also consumes low computational cost.
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