AUTOMATIC PARAMETRIZATION OF DIFFERENTIATED GLOTTAL FLOW - COMPARING METHODS BY MEANS OF SYNTHETIC FLOW PULSES

The automatic parametrization of the first derivative of glottal how i s studied. Representatives of the two types of methods used most often for parametrization were tested and compared. The chosen representati ves are all based on the Liljencrants-Fant model. As numerous tests we re needed for a detailed comparison of the methods, a novel evaluation procedure is used which consists of the following stages: (1) use the Liljencrants-Fant model to generate synthetic flow pulses; (2) estima te voice source parameters for these synthetic flow pulses; and (3) ca lculate the errors by comparing the estimated values with the input va lues of the parameters. This evaluation procedure revealed that in ord er to reduce the average error in the estimated voice source parameter s, the estimation methods should be able to estimate noninteger values of these parameters. The proposed evaluation method was also used to study the influence of low-pass filtering on the estimated voice sourc e parameters. It turned out that low-pass filtering causes an error in all estimated voice source parameters. On average, the smallest error s were found for a parametrization method in which a voice source mode l is fitted to the flow derivative, and in which the voice source mode l is low-pass filtered with the same filter as the flow derivative. (C ) 1998 Acoustical Society of America.