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(34)¡¡A MODEL TO REPRESENT PROPAGATION AND REDIATION
OF HIGHER-ORDER
¡¡¡¡¡¡¡¡MODES FOR 3-D VOCAL-trACT CONFIGURATION
¡¡¡¡¡¡¡¡¡¡Proceedings 1998 International Conference on Spoken Language Processing,Fr1R14,1998-12.
For the representation of acoustic characteristics of three-dimensional vocal-tract
shapes, it is necessary to consider the effects of higher-order modes. This paper
proposes an acoustic model of the vocal-tract which incorporates the coupling
of the higher-order modes, including both propagative and evanescent modes. A
cascaded structure of acoustic tubes connected asymmetrically is introduced as
a physical approximation of the vocal-tract. The acoustic characteristics, which
are dependent not only on the vocal-tract area function but also on the vocal-tract
configuration, can be investigated by the proposed model. Preliminary results
of numerical computations for relatively simple configurations suggest that additional
resonances at frequencies above 4.3kHz are formed by the propagative higher-order
modes, while those at frequencies below 3kHz are influenced by the evanescent
higher-order modes. These results are also confirmed by the FEM simulations.
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