Implementation of fast QMF-IIR filters based-on SBC technology on DSP
Chen Hai · Journal of Zhejiang University(Engineering Science) · 2002
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.