Consistency Analysis of the Duration Parameter Within a Syllable for Mandarin Speech
Keywords:Consistency analysis, hidden Markov model (HMM), vector quantization (VQ), text-to-speech (TTS), speech synthesis
This work presents a study of Mandarin speech focusing on consistency analysis of the duration parameter within syllables. Identified as a result of inspection of the human pronunciation process, this consistency can be interpreted as a high correlation between the warping curves of the spectrum and the prosody intra a syllable. Through three steps in the procedure of the consistency analysis, the HMM algorithm is used firstly to decode HMM-state sequences within a syllable at the same time as to divide them into three segments. Secondly, based on a designated syllable, the vector quantization (VQ) with the Linde-Buzo-Gray algorithm is employed to train the VQ codebooks of each segment. Thirdly, the duration vector of each segment is encoded as an index by VQ codebooks, and then the probability of each possible path is evaluated as a prerequisite to analyze the consistency. It is demonstrated experimentally that a consistency is definitely acquired in case the syllable is located exactly in the same word. These results offer a research direction that the time warping process intra a syllable must be considered in a TTS system to improve the synthesized speech quality.
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