ADAPTIVE CODEBOOK SEARCHING METHOD BASED ON CORRELATION FUNCTION IN CODE-EXCITED LINEAR PREDICTION CODING

摘要

PURPOSE: An adaptive codebook searching method based on a correlation function in code-excited linear prediction coding is provided to design an adaptive codebook with a scalar gain while having multi-tap structure. CONSTITUTION: A past excite signal is modeled through a second-order smoothing filter. A factor that minimizes the sum of squares of error signals is calculated. An excite signal is obtained using the calculated factor. A pitch delay and a gain value are obtained from the excite signal. A gain vector is estimated from the past excite signal and a three-dimensional gain vector is represented in scalar from the estimated value. Multi-gain is modeled into single-gain using correlation of the excite signal.