A fast search method of algebraic codebook by reordering search sequence

This paper proposes a fast search method of algebraic codebook in CELP coders. In the proposed method, the sequence of codebook search is reordered according to the criterion of mean squared weighted error between target vector and filtered adaptive codebook vector, and the algebraic codebook is searched until a predetermined threshold is satisfied. This method reduces the computations considerably compared with G.729 at the expense of a slight degradation of speech quality. Moreover, it gives better speech quality with smaller average search space than G.729A.