Studies of the line spectral frequency vector quantization in mixed excitation linear prediction
Xiao Dong Xiao Dong · Applied Acoustics · 2012
Line Spectral Frequency(LSF) is one of the most important parameters of the speech perception, it is also an effective expression of Linear Predication Coefficient (LPC) in a linear prediction model, and it reflects the modulation model of the acoustic tube. In standard Mixed Excitation Linear Prediction (MELP), LSF is hierarchically quantized using a 4-level codebook redundantly. In this paper, firstly, an improved codebook choosing algorithm is proposed by generating a 2-level codebook to replace the original 4-level one, so that to reduce the redundancy. Secondly, the method for perceptual quantization and appraisement is suggested to improve the speech quality, which is based on the experimental result that the speech quality is related to the quantization precision of LSF.