Identification of Stationary Parts of Speech Sounds
Frank A. Muller · The Journal of the Acoustical Society of America · 1956
An attempt has been made to identify vowel and fricative sounds experimentally with two parameters. These parameters are unique functions of a short-time power spectrum of the sound and vary continuously for any continuous variation of the spectrum. In this respect they differ from formant data. Such parameters can be derived in a multitude of ways. The parameters actually chosen should be comparatively insensitive to spectral differences that are found to be immaterial for aural identification. Weighted averages of the logarithm of the power spectrum turn out to have this property when the weighting functions are chosen adequately. A set of two parameters unite stationary speech sounds in a two-dimensional picture. The vowel part of it resembles the familiar vowel triangle, but in this picture the fricatives are added.