Second International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications (MAVEBA 2001)
The aim of this work is to investigate quantitatively the capability of the Continuous Wavelet Transform (CWT) as a tool to estimate (calculate) Jitter and Shimmer, assessing the error between these indices calculated in each Wavelet decomposition and the ones for the original signal, for several dilatation levels. It were generated 2 synthetic vowel /a/ with the fundamental frequency of 120Hz for male and 220Hz for female, by an autoregressive 22 coefficients all-pole model, and introduced Jitter and Shimmer on the signal using five different percent variations. The signals were decomposed by CWT in 8 levels of dilatation (1,2,4,8,16,32,64 and 128), using the Mexican Hat, Meyer and Morlet real bases. Jitter and Shimmer were calculated for the original signals and all the 8 levels of decompositions and then the errors between the indices in the decompositions and the original signals were calculated. It can be concluded that CWT can be used as a tool for preprocessing the signal to measure Shimmer preferentially, and Jitter, instead of using the original signal to do that. The Mexican Hat base provided the lowest errors for Shimmer analysis, where the best dilatation level was 8 (error below 0.1%). In addition, the errors associated with Shimmer index, in general, are lower than the ones associated with Jitter index.
Index Terms. Speech processing, Continuous Wavelet transform, Acoustic analysis of voice, Fundamental frequency analysis.
Bibliographic reference. Parraga, Adriane / Zaro, Milton A. / Schuck Jr, Adalberto (2001): "Quantitative assessment of the use of continuous wavelet transform in the analysis of the fundamental frequency disturb of the synthetic voice", In MAVEBA-2001, 134-137.