Physically oriented glottis models with inverse filtered waveform matching properties

A low-dimensional physically oriented model of the glottal source is discussed. The model relies on a lumped mechano-aerodynamic scheme based on the mass-spring paradigm. The vocal folds are represented by a mechanical resonator plus a delay line which takes into account the vertical phase differences. First, a simple flow model based on Bernoulli’s law is assumed, and the properties of the system are discussed. The class of models under consideration is shown to be able to reproduce a broad range of phonation styles, and to provide interesting control properties. Secondly, an extended flow model is introduced with the aim of reproducing realistic glottal source waveforms obtained by inverse filtering. The new flow model is based on a general parametric nonlinear model. For this new scheme, the principal characteristics of the flow-induced oscillations are retained, and the overall model is suited for an identification approach where real inverse filtered glottal flow signals are to be reproduced. A data-driven identification procedure is outlined, where the parameters of the model are tuned in order to accurately match the target waveform. A set of inverse-filtered glottal flow wave forms with different characteristics are used to test the effectiveness of the approach. The results demonstrate that the model can reproduce a wide range of target waveforms.