Vector quantization of glottal pulses
Thomas Eriksson, J. Linden, Jan Skoglund · 1995
An efficient codebook driven voiced excitation coding method producing natural sounding speech is proposed. It can be incorporated as an essential part in a complete speech coder working at low bit rates. The inter-pulse correlation of such a coding scheme is investigated and exploited using linear predictive vector quantization and finite state vector quantization (FSVQ). A new and more robust FSVQ method that is able to more efficiently exploit this correlation is proposed. The new method dynamically combines two memoryless vector quantizers. This dynamic combination method is not restricted to pulse codebooks but can be employed for any coding scheme with inter vector correlation. 1. INTRODUCTION Most modern speech coders are based on the source-filter concept which tries to separate the excitation source waveform from the spectral characteristics of the vocal tract. For voiced speech, the excitation waveform essentially describes the airflow through the vocal folds. For coders op...