矢量量化法用于改进的多带激励声码器一种极低比特率语音编码方案

Improved Multi-Band Excitation Vocoder with Vector Quantization-An Extremely Low Bit Rate Speech Coding Strategy

在低比特率语音编码方法中，改进的多带激励编码方法可得到低噪声和稳健性强的重建语音，但运算量很大．作者在改进的多带激励编码研究中，将矢量量化方法引入频谱幅度的量化，不仅降低了运算量而且降低了编码比特率，使得在１．３５～１．８ｋｂｉｔ／ｓ的编码比特率下的重建语音，与４．８ｋｂｉｔ／ｓ编码比特率下（按自激励声码器编码方法）重建的语音质量相比毫不逊色．

Among the low bit rate speecd coding methods, IMBE coding is a type characterized by low noise and high robustness, yet it is also the most complicated in computation. Based on vector quantization introduced into IMBE coding for spectrum amplitudes, the authors developed a coding strategy more efficient not only in bits spent but also in computation. With the VQ-IMBE coding, a bit rate as low as 1 350～1 850bit/s can be achieved without losing reconstructed speech quality in comparison with that obtainable with the self exited vocoders.