A low-complexity 3.6kb/s speech coding algorithm based on mixed excitation is presented in this paper. It uses the parameter encoding and mixed excitation technology to ensure the quality of speech. Through adopting the scalar quantization of Line Spectrum Frequency (LSF), the algorithm reduces the storage and computational complexity. Meanwhile, improved frame type with dynamic Unvoiced/Voiced (U/V) thresholds make a reduction of the traditional U/V decision error and the sudden transformation of U/V frame. A modified bit allocation table is introduced and the PESQ-MOS test shows that the synthetic speech quality has been improved and reached the quality of communication, especially for high frequency female speakers with new frame type.
SWITCHED UNIFORM SCALAR QUANTIZATION ADAPTED TO MEAN AND VARIANCE FOR SPEECH CODING
