Pitch and band-pass voicing strengths coefficients joint quantization algorithm
Tang Kun · Journal of Tsinghua University(Science and Technology) · 2008
A joint quantization algorithm based on index allocation was developed to improve the precision of pitch quantization and speech quality for low-bit-rate vocoders.The algorithm divides the code index space according to the band-pass voicing strengths coefficients(BPVC) mode.The size of the code book for the pitch is enlarged in the all-voiced mode so that the pitch can be more exactly quantized.Experiment results show that the algorithm reduces the pitch quantization error by 20% compared to the vector quantization algorithm which remarkably improves the synthesized speech quality.