Harmonic coding has reached a state of maturity where real-time implementation can already be envisaged. However, there is still a long way before one can say that harmonic coding concepts are fully explored. This paper attempts to pinpoint the weakest features of harmonic coding and improving them. One of the main criticisms pointed to harmonic coders is the heavy dependence of the output quality on the performance of the pitch estimation and voicing decision algorithms. Pitch and voicing estimation, therefore, was one of the first problems addressed in this study. Another one is phase encoding, which we have previously reported as a major source of degradation at 4. 8 Kb/s. Finally, since the coder is sensitive to pitch and voicing decision, an important question concerns its performance with noisy speech input. All these problems are addressed on the present study. Keywords: sinusoidal / harmonic coding; speech coding.
Bibliographic reference. Marques, J. S. / Trancoso, Isabel M. / Abrantes, A. J. (1991): "Harmonic coding of speech: an experimental study", In EUROSPEECH-1991, 235-238.