Teza doctorat (pdf) - Universitatea Tehnică

O. Buza, G. Toderean, J. Domokos, A. Zs. Bodo, Construction of a Syllable-Based Text-To-Speech System for Romanian
Number of zero-crosses is a characteristic used in determining voiced/unvoiced feature of
speech segments. Inside voiced segments number of zero-crosses is lower, while inside unvoiced
segments this parameter has much higher values.
Fundamental Frequency is an important parameter used in voice synthesis that
corresponds with the signal periodicity. This parameter must be computed on short segments of
time, because of speech signal variability. Fundamental frequency is calculated only for voiced
segments where the signal is almost periodical, while unvoiced segments are nonperiodical signals
and they have not fundamental frequency.
For computing this parameter we have developed a time-domain method based on local
maximum and minimum values of signal amplitude, as one can find in [9].
3. SPEECH SEGMENTATION
Finding an optimal approach for speech signal segmentation is an imperative in building
acoustic database of a voice synthesis system. This section presents a segmentation method that
have been designed and implemented by the authors, method which is capable to detect S/U/V
(Silence- Unvoiced- Voiced) components of speech signal, to divide these components in regions
with specific characteristics, and to associate regions with a known phonetic input sequence
(figure 2):
Speech signal
S/U/V Segmentation
Compaction
Region
Classification
Phonetic
Segmentation
Figure 2. Speech signal segmentation
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