Method for forming the excitation signal for a glottal pulse model based parametric speech synthesis system

A method performed by a processing circuit for creating parametric models for use in training a speech synthesis system, wherein the system comprises at least a training text corpus, a speech database, and a model training module, the method comprising:

• a. obtaining, by the model training module, speech data from the speech database wherein the speech data comprises recorded speech signals and corresponding portions of the training text corpus;
• b. converting, by the model training module, the training text corpus into context dependent phone labels;
• c. extracting, by the model training module, for each frame of speech in the speech signal from the speech data, at least one of:
• spectral features, a plurality of band excitation energy coefficients, and fundamental frequency values using the context dependent phone labels;
• d. forming, by the model training module, a feature vector stream for each frame of speech in the speech signal from the speech data using the at least one of:
• the spectral features, the plurality of band excitation energy coefficients, and the fundamental frequency values;
• e. labeling, by the model training module, each frame of speech in the speech signal with the context dependent phone labels;
• f. extracting, by the model training module, durations of each of the context dependent phone labels from the labeled speech;
• g. forming, by the model training module, context dependent Hidden Markov Models (HMMs) using the feature vector streams and the context dependent phone labels from the labeled speech;
• h. performing, by a parameter generation module, parameter estimation of the speech signal, wherein the parameter estimation is performed comprising the feature vector streams, the HMMs, and decision trees;
• i. identifying a plurality of sub-band Eigen glottal pulses from the speech signal, wherein the sub-band Eigen glottal pulses comprise separate models used to form excitation during synthesis;
• and
• j. applying the identified plurality of sub-band Eigen glottal pulses from the speech signal to form an excitation signal, wherein the excitation signal is applied in the speech synthesis system to synthesize speech.