Research Of Variable Rate Speech Coding Based On TMS320C6713

Speech communication is a basic and useful way to get information, and the key technique of speech communication is speech compress coding. To meet the needs of the third mobile communication system for higher speech quality and greater system capacity, it is trend of digital cellular and micro cellular network to improve utilization extent of band using variable rate speech coding. SC-VR-CELP model is high-quality variable bit rate speech coding algorithm, it is low average rate and good rebuild speech and better ability of anti-disturbance. To meet the requirement for data large dynamic range, high precision real-time processing, Texas Instrument high performance 32-bit floating-point DSP TMS320C6713 is selected. The principles and implementation of SC-VR-CELP algorithm on DSP processor are discussed in this paper.The principle of the algorithm of SC-VR-CELP is studied in this paper, Moreover some important technologies including VAD, Speech Classed,RDA,Linear-Prediction,Vector Quantization, Adaptive-codebook Search,and Fixed-codebook Search have been analyzed in detail. Then TMS320C6713DSK is selected as hardware platform, this paper introduces the structure and work principle for the TMS320C6713 and AIC23Codec.The programme of SC-VR-CELP algorithm is compiled using the C language and realized using VC6.0. The successful C procedure is transplanted to Code Composer Studio3.1 in order to be realized in the TMS320C6713 DSK. In the programming process a series of optimization work is performed to implement the algorithm better. The optimized method included DSP chip and c language and assembly language. Finally, the system is tested and the performance is analyzed. Through tested result, the system can availability implement encoding and decoding to the real-time voice. Quality of voice reconstructed is well understood.The rate and quality of SC-VR-CELP reach require of mobile communication, which can be applied mobile communication, and increase the system capacity in contrast to fixed speech coding .