Mixed Spectral Representation -- Formants and LPC Coefficients

A cascade formant model is well suited to describe certain speech segments such as vowel and vowel like sounds. The formant model is also useful because the relationship between formants and vocal tract configurations is well understood. However, this model is not adequate for other speech sounds such as stops fricatives and nasals. On the other hand, LPC analysis of order 10 to 16 can adequately describe the spectrum of any speech sound; however the relationship between the LOC parameters and the spectrum or vocal tract configuration is not obvious. This paper describes a speech analysis/synthesis scheme that uses formants and LPC parameters for different sections of a speech signal. Thus in some regions we have the benefits of the formant model, and in other regions, we can use the LPC representation to obtain a good description of the speech spectrum. The method of speech analysis described in this paper produces resynthesized speech of the quality of Multi-Pulse LPC.