Research And Implementation Of The Mcu-based Digital Voice Processing

By the developing of communication and information technology, the market of communication terminal brings forward the needs of low cost telephone with DAM function. In order to meet the needs, this project designs and realizes a concise Adaptive Difference Pulse Code Modulation arithmetic, and applies it successfully to a low cost DAM project.This thesis introduces the course, the research actuality of speech compression code and the common speech code arithmetic, and analyzes the general theory, classifying and kinds of realization of speech code arithmetic; Then, the thesis introduces the designing of the low cost DAM, designing the system hardware structure and the coder arithmetic for meeting the DAM project, and comparing the system with some other ones using DSP chip; The thesis depicts the designing idea of the concise ADPCM, and describes it in detail with five module, for example, predictor and difference calculation, adaptive quantization and so on, then describes the data structure and coder function of it with C program language, and compares the arithmetic with G.726; The thesis dissertates emphatically the realization of the concise ADPCM arithmetic in system, introduces the data structure in assembler program, describes the flow chart of the program that implements the record and play voice, the coder and decoder of speech signal; Finally, the thesis summarizes the result of the project, and describes the evaluation to the voice quality and publishes the MOS score of it, and puts forward the next continued task of research.The thesis achieves the designing of the low cost DAM at last, and has made the test sample machine via repetitious simulation experiment and iterative debug, it now has gained expected purpose and should be applied to the mass production.