Method for searching codebook in CELP Vocoder using algebraic codebook

摘要

PURPOSE: A method of searching a codebook of a code excited linear prediction (CELP) vocoder using an algebraic codebook is provided to search the algebraic codebook with a small amount of calculations using a search tree restricting method. CONSTITUTION: A method of searching an algebraic codebook of an algebraic CELP vocoder using a depth-first tree search method includes a step(100) of searching up to a specific level of trees in order to predict a tree where an optimum pulse is positioned, a step(200) of selecting a predetermined tree according to the search result and removing other trees, and a step(300) of searching only the selected tree to select an optimum algebraic code.