Effect of the vocal tract filtering on the measurement of vocal cycle perturbations. Issue 18 (1st July 2020)

• Record Type: Journal Article
• Authors: Bennane, Y.; Kacha, A.
• Is Part Of: Electronics letters. Volume 56:Issue 18(2020)
• Page Start: 964
• Page End: 966
• Publication Date: 2020-07-01
• Subjects: speech -- transfer functions -- speech processing -- jitter -- amplitude modulation -- acoustic signal processing; glottal excitation signal -- vocal tract filtering -- vocal cycle perturbations -- cycle‐to‐cycle variation -- cycle length -- cycle amplitude -- phonatory excitation -- vocal jitter -- amplitude modulation -- speech signal -- vocal tract transfer function -- glottal excitation cycles -- vocal perturbations -- vocal tract model; Electronics -- Periodicals; 621.381
• DOI: 10.1049/el.2020.0620
• Languages: English
• ISSNs: 0013-5194

Abstract

Abstract : Jitter and shimmer appear as symptoms of disordered voices and they are defined as the cycle‐to‐cycle variation of the cycle length and cycle amplitude, respectively. The frequency modulation of the phonatory excitation, i.e. vocal jitter, causes amplitude modulation (shimmer) of the speech signal due to the action of the vocal tract transfer function. In this Letter, the authors investigate the extent to which the vocal tract filtering affects the accuracy of measurement of vocal cycle perturbations of the phonatory excitation. To achieve this goal, the direct digital synthesiser is used to generate a series of glottal excitation cycles with the desired amount of vocal perturbations that crosses the vocal tract model to produce a set of 231 stimuli of sustained vowels [a]. Praat is used to measure the amount of perturbations. Results show that the values of the input shimmer inserted in the glottal excitation are smaller than the values measured by Praat. An undesired amount of shimmer is generated in the speech signal when the glottal excitation signal perturbed with jitter crosses through the vocal tract.