Speech analysis is performed by synchronizing (36) with the initiation of glottal pulses produced during the voicing of phonemes, a pitch-independent transform that performs analysis entirely within a pitch period. Analysis is made of the three most dominant formant frequencies (48, 50, 52) of the sound sets involved in the enunciation of voiced phonemes. Peaks in the transform represent formant frequencies. Three peaks are selected from the transform identifying the frequencies with the first, second and third greatest amplitudes. Correlation of the waveform (27, 28) between successive pitch periods detects whether a sound is a vowel, a voiced sibilant, or unvoiced. Unvoiced sound sets are similarly analyzed but the analysis is synchronized with artificially generated synch pulses. Formant ratios are encoded (58).
METHOD AND APPARATUS FOR SPEECH ANALYSIS