摘要
研究了子带编码(SBC)技术,阐述了一种32kbit/s的语音编码方案,介绍了子带编码方案的总体设计思想.在相同的比特速率下,子带编码器能获得明显优于整个频带编码的信号质量.要使滤波器具有很陡峭的带通特性,以防止采样率降低,即抽取过程中产生混叠现象,对一般的数字滤波器来说运算量比较大,但子带编码采用正交镜像滤波器QMF以及抽取、内插方法可以大大改善带通滤波器的特性.设计仿真了其关键技术QMF-IIR滤波器组,并由DSKPlus开发板实现,取得了较好的效果.
A 32 kbit/s Subband Coding(SBC) based on speech code system and the implementation of IIR filter on DSKplus are presented in this paper. At the same bit rate, Subband Coding can reach higher signal quality than fullband Coding. In order to prevent the overlap caused by the attenuation of sampling rate, a filter should steep bandpass characteristic. For a simple digital filter, the computation complexity is too high. But using quadrature mirror filter and interpolation technology, Subband Coding can greatly improve the characteristic of bandpass filter charaeteristics. This assumption was simulated in MATLAB System View and its implemented on DSK Plus, yielded the expected effect. At the end of this paper, some methods to improve the performance of the speech code system are offered.
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2002年第6期650-654,共5页
Journal of Zhejiang University：Engineering Science
基金
浙江省综合信息网重点实验室开放课题基金资助项目(J30174).
