An 800 bit/s vector quantization LPC vocoder
An 800 bit/s vector quantization LPC vocoder
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800 bit/s 矢量量化 LPC 声码器
DOI：
10.1109/tassp.1982.1163960
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
A. Gray
中科院分区：
文献类型：
--
作者：
D. Wong;B. Juang;A. Gray
研制了一种800bit/S的矢量量化线性预测编码声码器。应用最近发展的LPC矢量量化理论，将LPC系数编码的比特率降低了4倍。为了提高算法效率，采用了分支搜索技术和清浊码本分离技术。应用差分编码以将基音和增益参数的比特率降低三分之一。形式主观评价表明，800bit/S声码器保留了线性预测编码系统的大部分可懂度。在不同的传输误差和声学条件下，该算法也具有较强的鲁棒性。非正式的听力比较显示，质量是可以接受的，有时非常接近2400bit/S LPC语音。800bit/S声码器的计算成本相当于甚至低于2400bit/S LPC-10。由于800bit/S的设计只在量化和编码算法上有所不同，因此保证了与任何LPC-10声码器的兼容性。可以通过去除编码中的帧到帧冗余来实现进一步的比特率降低。
An 800 bit/s vector quantization linear predictive coding (LPC) vocoder has been developed. The recently developed LPC vector quantization theory is applied to reduce the bit rate for LPC coefficients coding by a factor of four. Branch search techniques and separation of voiced and unvoiced codebooks are applied for better algorithm efficiency. Differential coding is applied to reduce the bit rate for the pitch and gain parameters by one third. Formal subjective evaluation shows that the 800 bit/s vocoder preserves most of the intelligibility of an LPC system. It is also robust under different transmission error and acoustic conditions. Informal listening comparisons show the quality to be acceptable and sometimes very close to 2400 bit/s LPC speech. The computational cost of the 800 bit/s vocoder is equivalent to or even lower than the 2400 bit/s LPC-10. Compatibility with any LPC-10 vocoder is guaranteed because the 800 bit/s design only differs in the quantization and encoding algorithms. Further bit rate reduction can be achieved by removing frame to frame redundancy in the code.