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 f orm of code-excited linear prediction (CELP). Since its invention in 1 984 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 comple xity. Three new excitation types, all of which are based on a pulsed r esidual, are proposed. The new pulsed residual excitations improve the speech quality significantly. In addition a novel mathematically equi valent codebook search method which reduces the search complexity sign ificantly is described.