Synthesis filter optimization and coding: Applications to CELP [speech analysis]

Code-excited linear prediction (CELP) is examined for the coding of speech signals. The methodology is developed to allow for a joint optimization of waveform selection, waveform scaling, and pitch filter determination. Methods to accommodate high-pitch speakers (pitch lag smaller than the analysis frame size) are given. The requirements for coding the synthesis parameters into a bit stream at 4.8 kb/s are discussed. The coder has been tested at channel error rates of 0.001, with only minor degradations in the resulting speech. An adaptive postfilter has been added to achieve a small increase in perceived speech quality