Abstract
A qualitative study of mechanisms of jitter-induced shimmer in the voice
The Journal of the Acoustical Society of America, Vol.97(5_Supplement), pp.3421-3421
05/01/1995
DOI: 10.1121/1.412415
Abstract
Measurements of jitter and shimmer are typically applied to microphone signals to discern the level of perturbations in the oscillatory behavior of the vocal folds. Shimmer, the average cycle-to-cycle change in amplitude, is known to linearly increase as the extent of amplitude modulation of tissue displacement increases. Behavior under frequency modulation (FM), however, is nonlinear. This nonlinearity is often attributed to time aliasing, the superposition of jittered impulse responses (assuming the source-filter model of phonation). As a consequence, whenever jitter is present, any measurement of shimmer cannot be solely attributed to amplitude modulation of the vocal fold tissue. The present study attempts to characterize other sources of FM-induced shimmer by examining points earlier in the voice production process. An interactive computer simulation of the vocal fold and vocal tract system is used under conditions of FM1/2 subharmonic modulation of the tissue displacement. It appears that, in addition to time aliasing, shimmer may be generated from FM-induced perturbations in mucosal wave propagation and tissue displacement. The paper qualitatively describes and illustrates these jitter-induced shimmer mechanisms.
Details
- Title: Subtitle
- A qualitative study of mechanisms of jitter-induced shimmer in the voice
- Creators
- Darrell Wong - Denver Center for the Performing ArtsRobert LangeIngo R. Titze - University of IowaChwen Geng Guo
- Resource Type
- Abstract
- Publication Details
- The Journal of the Acoustical Society of America, Vol.97(5_Supplement), pp.3421-3421
- DOI
- 10.1121/1.412415
- ISSN
- 0001-4966
- Number of pages
- 1
- Language
- English
- Date published
- 05/01/1995
- Academic Unit
- School of Music; Communication Sciences and Disorders
- Record Identifier
- 9984719853802771
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