On certain irregularities of voiced-speech waveforms

In the process of studying voiced speech signals, it is frequently found that waveforms exhibit irregularities with respect to their expected periodicity. The purpose of this study is to investigate the underlying causes of such irregularities. The phenomenon was investigated simultaneously by means of the following methods: 1) larynx-microphone signal representation, and 2) glotto-graphic signal representation. In order to establish whether the effect depends on the particular speaker, the phenomenon was studied on a number of different voices. Dependency on other causes, such as source-signal irregularities, sudden vocal-tract variations, etc., was also studied. In connection with this study, a method of evaluating the relative merits of various pitch extractors was developed and will also be described.