Automatic speech recognizer for real time operation

Abstract

A speech recognizer identifies an unknown utterance as a variable length string of stored reference patterns in a single pass through the time frame sequence of utterance feature signals. A plurality of reference pattern levels are used to permit strings of varying lengths. As each utterance time frame portion is received, its acoustic feature signals are time registered with the reference pattern feature signals at each reference pattern level to form reference pattern endframe registration path and registration path correspondence signals. Responsive to the plurality of level reference pattern end frame registration path signals, reference pattern strings are selected for the current utterance frame. The utterance is identified as the selected reference string with the best correspondence to the utterance from the registration path signals of the reference levels of the last utterance time frame.