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The Effect of Voice over IP Transmission Degradations on MAP-EM-GMM Speaker Verification Performance

Maciejko W.

Archives of Acoustics

2015

Vol. 40, No. 3

407--417

Despite the growing importance of packet switching systems, there is still a shortage of thorough analyses of VoIP transmission effect on speech and speaker recognition performance. Voice over IP transmission systems use packet switching. There is no guarantee of delivery. The main disadvantage of VoIP is a packet loss which has a major impact on the performance experienced by the users of the network. There are several techniques to mask the effects of a packet loss, referred to as packet loss concealment. In this study, the effect of voice transmission over IP on automatic speaker verification system performance was investigated. The analyzed system was based on MAP-EM-GMM modelling methods. Four various speech codecs of H.323 standard were investigated with special emphasis placed on the packet loss phenomenon and various packet loss concealment techniques.

Optimization of μ-law companding Quantizer for Laplacian source using Muller’s method

Nikolić J., Perić Z., Aleksić D.

Przegląd Elektrotechniczny

2013

R. 89, nr 3a

206--208

The motivation of this paper is based on the fact that a straightforward solution to optimization of the widely used μ-law companding quantizer has not been proposed so far. We deal with this problem for the case of a Laplacian source and we apply Muller’s method for the optimization of the quantizer in question. Particularly, we use minimal distortion criteria and we apply Muller’s method in order to determine the key parameter of the μ-law companding quantizer. The optimization method we propose is very general and it is easily modified for non-Laplacian sources. It can be applied for speech compession, because speech signals are well modeled by Laplacian sources.

W artykule opisano sposób optymalizacji kwantyzatora kompansji u-law. Do tego celu zastosowano metodę Muller’a oraz kryterium minimalnych zakłóceń. Proponowana optymalizacja jest ogólna i może być zmodyfikowana dla źródeł nielaplasjanowych.

Estimation of the Fundamental Frequency of the Speech Signal Compressed by MP3 Algorithm

Milivojević Z. N., Brodić D.

Archives of Acoustics

2013

Vol. 38, No. 3

363--373

The paper analyzes the estimation of the fundamental frequency from the real speech signal which is obtained by recording the speaker in the real acoustic environment modeled by the MP3 method. The estimation was performed by the Picking-Peaks algorithm with implemented parametric cubic convolution (PCC) interpolation. The efficiency of PCC was tested for Catmull-Rom, Greville, and Greville two- parametric kernel. Depending on MSE, a window that gives optimal results was chosen.