METHOD OF PERFORMING SEQUENTIAL OPTIMIZING PROCESS FOR SEARCHING ALGEBRAIC CODE-BOOK OF VOICE CODING SYSTEM FOUNDATION

摘要

PURPOSE: A method for performing a sequential optimizing process for searching algebraic code-book of a voice coding system is provided to check contributions relating to each pulse location according to a code vector supplied from the algebraic code-book, and to decide threshold values of each track relating to the contributions to retrieve a pulse combination only, over the threshold values among each pulse according to the code vector, so as to perform a code-book searching process at a high speed. CONSTITUTION: A pulse contribution checker checks contributions relating to 40 pulse locations in each track supplied from a code-book(22). The pulse contribution checker stores contributions relating to each pulse location in a predetermined memory(24). A threshold value decider decides threshold values(t) relating to each track by using the contributions(26). A comparator checks whether the contributions are over the threshold values(28). If the contributions are less than the threshold values, a contribution of a next pulse location is inputted to perform the step 'S28'(29). If the contributions are over the threshold values, pulse combinations composed of pulse locations which are over each threshold value are generated(30). Mean squared errors(MSEs) relating to each pulse combination are calculated(32). A pulse combination having a minimal MSE is decided(34). An optimum code vector is generated by using the decided pulse combination(36).