Parameterization of the glottal flow is a process where the glottal flow is represented in terms of a few numerical values. This study proposes a novel parameterization technique called the phase plane symmetry (PPS) parameter that utilizes the symmetrical properties of the phase plane plot. Phase plane is a way to graphically visualize the glottal source in a 2-dimensional space spanned by two amplitude-domain axes. A correctly normalized phase plane plot has also close ties to the normalized amplitude quotient (NAQ) parameter, and it is shown that the inverse NAQ value is represented as a single point in the phase plane plot. The experiments conducted in this study support that PPS is powerful in discriminating between various phonation types and within the same range of robustness as the NAQ parameter.
Bibliographic reference. Airaksinen, Manu / Alku, Paavo (2014): "Parameterization of the glottal source with the phase plane plot", In INTERSPEECH-2014, 96-100.