Method for processing speech signal using sub-converting functions and a weighting function to produce synthesized speech

A speech synthesizing method comprising:

• a first step of receiving speech synthesis input information including phoneme series information and accent information representative of the contents of speech;
• a second step of generating and outputting a plurality of sound spectrum parameters corresponding to said speech synthesis input information;
• a third step of converting said plurality of sound spectrum parameters to a desired sound spectrum parameter by a predetermined parameter converting function constituted of a plurality of sub-converting functions and a weighting function for setting weighting coefficients on a space of vectors of said sound spectrum parameters, said weighting function including a radial basis function having a non-increasing output value for an increase in the distance between a central vector of the M-dimension defined on said vector space of said sound spectrum parameters and each said sound spectrum parameter;
• and
• a fourth step of synthesizing a speech waveform corresponding to said desired sound spectrum parameter by using said desired sound spectrum parameter,
• wherein said third step includes the steps of:
• converting said plurality of sound spectrum parameters by using said plurality of sub-converting functions to generate respective conversion outputs;
• giving said weighting coefficients to said conversion outputs to generate weighted conversion outputs;
• and
• calculating the sum of said weighted conversion outputs and outputting said sum output as said desired sound spectrum parameter.

An apparatus for synthesizing an input speech signal comprising:

• a receiver for receiving M-dimensional input vectors;
• a convertor for converting said M-dimensional input vectors to N output vectors in accordance with a predetermined parameter converting function, wherein said output vectors are representative of the phonemes in said input speech signal;
• and
• said parameter converting function comprises a plurality of sub-converting functions and a weighting function for setting weighting coefficients related to a predetermined space within which each of said M-dimensional input vectors exists.