Glottal-to-Noise Excitation Ratio – a New Measure for Describing Pathological Voices

In this article a new acoustic parameter for the objective description of voice quality is introduced. It is based on the correlation coefficient for Hilbert envelopes of different frequency bands. The parameter indicates whether a given voice signal originates from vibrations of the vocal folds or from turbulent noise generated in the vocal tract and is thus related to (but not a direct measure of) breathiness. Therefore it is named Glottal-to-Noise Excitation Ratio (GNE Ratio). GNE is compared to HNR (Harmonics-to-Noise Ratio) and NNE (Normalized Noise Energy), existing measures also sensitive to additive noise (turbulence). Experiments with artificial signals show that only the GNE is almost independent of frequency modulation noise (jitter) and amplitude modulation noise (shimmer).