Abstract: In distinguishing between voiced and unvoiced speech elements use is made of the fact that the spectra of voiced sounds lie predominantly at or below about 1 kHz, and the spectra of unvoiced sounds lie predominantly at or above about 2 kHz. 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.

Abstract: Speech recognition is performed in several successive phases, with each word being separated into elements of equal length. Each element is represented by a vector consisting of eight coefficients. After the end of a word is recognized, the word is successively compared with all reference words in a speech recognition apparatus. The recognition process is speeded up through the utilization of common hardware for all phases and by avoidance of idle time. A cellular array processor is used whose processing elements operated predominantly as filters in the feature extraction phase, and each element compares two vectors in the comparison phase. By gradual transitions between ends and beginnings of words, the capacities of all processors are equally utilized. The exchange of data is practically limited to an exchange between adjacent processors and is thus very efficient.