Patent Document ID: 4763278
Application ID: 06484820

Base Claim:
1. A method for recognizing speech independent of the speaker thereof, said method comprising: receiving an analog input speech signal; conditioning said analog speech signal to produce a sequence of rectangular waveforms of polarity signs alternating between plus and minus polarities as a digital waveform signal; counting the number of polarity transitions in the digital waveform signal to obtain a zero-crossing count for each frame of the digital waveform signal; measuring the time duration intervals between zero-crossings of the digital waveform signal; providing a sequence of binary feature vectors based upon the measurements of the time duration intervals between zero-crossings of the digital waveform signal and corresponding to respective frames of the digital waveform signal; providing a vocabulary consisting of a relatively small number of words, wherein each of the words included in the vocabulary is represented by a plurality of binary reference vectors which have been organized in sequences with each of said binary reference vector sequences corresponding to a word acoustically distinct from the other words included in the vocabulary; comparing each of said binary feature vectors with each of said plurality of binary reference vectors; determining a distance measure with respect to each of said binary reference vectors for each successive binary feature vector in said sequence of binary feature vectors in response to the comparison therebetween; and recognizing words in accordance with the distance measures between each of said binary reference vector sequences and successively received binary feature vectors corresponding to respective frames of the digital waveform signal.

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Claim 4:
4. The method of claim 1, wherein said distance measure-determining step comprises a Hamming distance measurement.