METHOD FOR PERFORMANCE IMPROVEMENT OF PITCH POST FILTER IN VOICE SIGNAL PROCESS DECODER

摘要

PURPOSE: A method for performance improvement of pitch post filter in voice signal process decoder is provided to gain an accurate pitch delay by normalizing energy level of a recovered residual signal used as an input of a pitch post filter to a constant level. CONSTITUTION: A first process(S10) produces an average energy of a recovered residual signal. A second process(S20) sets up a pitch section in a sub-frame by using a recovered pitch delay. A third process(S30) produces an average energy every pitch delay section. A fourth process(S40) calculates a ratio of the average energy to an inner energy of the pitch section. A fifth process(S50) performs energy increase or decrease of a signal in the pitch section according to the magnitude of the energy ratio.