A 4.8 k bps homomorphic vocoder using analysis-by-synthesis excitation analysis

A novel homomorphic vocoder producing good quality speech at 4.8 kb/s is presented. In this homomorphic vocoder framework, the real cepstra containing vocal tract information are vector quantized and the excitation signals are obtained applying an analysis-by-synthesis method using a weighting filter which is derived from the cepstrum. Informal listening tests show that this vocoder is fully competitive with the code-excited linear predictive coder in producing good-quality speech at 4.8 kb/s