Research And Implementation Of Speech Coding Algorithm Based On ADPCM

Adaptive Differential Pulse Code Modulation (ADPCM) is an effective algorithm of speech coding. It adopts the method of adaptive quantization and adaptive prediction to compress pulse code modulation (PCM) signal. In this thesis, we implemented the algorithm of speech compression coding in recommendation G.726 and a program of ADPCM encoder. Otherwise, this thesis discussed the implementation of ADPCM decoder.G.726 is one of the algorithm recommendations of ADPCM, and it is on a basis of the ADPCM theory. Firstly, the thesis introduces the algorithm theory of ADPCM.Secondly, each algorithm module in the recommendation algorithm has been implemented. This part is the key point in this thesis. we divide the algorithm into two modules. One is adaptive quantization, and anther is adaptive prediction. In adaptive quantization algorithm, six sub-modules have been implemented. They are Input PCM format conversion, Difference signal computation, Quantizer scale factor adaptation, Adaptation speed control, Tone and transition detector, and Adaptive quantizer. In adaptive prediction algorithm, two sub-modules, Inverse adaptive quantizer, and Adaptive predictor and reconstructed signal calculator, are implemented.Finally,on a basis of comprehension of encoder flow and implementation of algorithm modules, an encoder program is be achieved using Object-Oriented...