BLOCK-CONSTRAINED TRELLIS CODING QUANTIZATION METHOD AND METHOD AND APPARATUS FOR QUANTIZING LINE SPECTRAL FREQUENCY COEFFICIENT IN SPEECH CODING SYSTEM

摘要

PURPOSE: A BC-TCQ(Block-Constrained Trellis Coding Quantization) method and a method and apparatus for quantizing an LSF(Line Spectral Frequency) coefficient in a speech coding system are provided to reduce a memory size required for quantizing input signals and coefficients and decrease the quantity of computations and complexity in a codebook search process. CONSTITUTION: A DC component is removed from an input LSF coefficient vector(121). Inter-frame and intra-frame predictive coding is carried out for the LSF coefficient vector to generate the first predictive error vector. The first predictive error vector is quantized using BC-TCQ algorithm and inter-frame and intra-frame predictive compensation is performed to generate the first quantized LSF coefficient vector(122). Intra-frame prediction is carried out for the LSF coefficient vector from which the DC component was removed to generate the second predictive error vector. The second predictive error vector is quantized using BC-TCQ algorithm and intra-frame predictive compensation is performed to generate the second quantized LSF coefficient vector(123). One of the first and second LSF coefficient vectors, which has smaller Euclidean distance from the input LSF coefficient vector is selectively output(124).