The spectra of voiced sounds lie predominantly at or below about 1 kHz. The spectra of unvoiced sounds lie predominantly at or above about 2 kHz. It is known to determine the lower- and higher-frequency energy components contained in a sound or sound element, to compare these energy components, and to use the result of the comparison to make a voiced-unvoiced decision. Since the distributions relative to voiced and unvoiced segments are overlapped, false decisions are liable to occur. The invention is predicated on the fact that a change from a voiced sound to an unvoiced sound or vice versa always produces a clear shift of the spectrum, and that without such a change, there is no such clear shift. From the lower-and higher-frequency energy components, a measure of the location of the spectral centroid is derived which is used for a first decision. Based on the difference between two successive measures, a second decision is made by which the first can be corrected.
Method of and arrangement for distinguishing between voiced and unvoiced speech elements.