Pulsed residual excited linear prediction

Linear predictive coding of speech has been widely used at 16 kb/s in the form of adaptive predictive coding (APC) down to 4.8 kb/s in the form of code-excited linear prediction (CELP). Since its invention in 1984 there have been many variations of CELP which differ mainly in the way the final excitation signal (codebook) is produced and quantised. These variations either produce better speech quality or lower complexity. Three new excitation types, all of which are based on a pulsed residual, are proposed. The new pulsed residual excitations improve the speech quality significantly. In addition a novel mathematically equivalent codebook search method which reduces the search complexity significantly is described.