G.726标准ADPCM编码方法研究与仿真

G.726标准ADPCM编码方法研究与仿真G.726标准ADPCM编码方法研究与仿真摘要摘要本设主要利用MATLAB，设计一个ADPCM编码系统，使其符合G.726标准。自适应差分脉冲编码调制（AdaptiveDifferentialPulseCodeModultion）采用自适应量化方法和自适应预测方法，对PCM语音信号进行再压缩，是一种有效的语音信号波形编码压缩方案。而本设计从自适应差分脉冲编码调制编码基础理论出发，实现了G.726标准语音压缩编码算法，并在该算法的基础上实现了自适应差分脉冲编码调制解码器程序。本文重点叙述标准中的各个算法模块的实现。该设计将编码算法从整体上划分为自适应量化和自适应预测两个模块：在自适应量化模块中，分别实现了输入PCM格式转换、差分信号计算、量化定标因子自适应、自适应速度控制、单音信号和转移（瞬变）检测以及自适应量化6个子算法；在自适应预测模块中，实现了反向自适应量化以及自适应预测和重建信号子算法。关键词：G.726标准；ADPCM；自适应量化；自适应预测G.726标准ADPCM编码方法研究与仿真G.726STANDARDADPCMCODINGANDSIMULATIONABSTRACTAdaptiveDifferentialPulseCodeModulation(ADPCM)isaneffectivealgorithmofspeechcoding.Itadoptsthemethodofadaptivequantizationandadaptivepredictiontocompresspulsecodemodulation(PCM)signal.Inthisthesis,weimplementedthealgorithmofspeechcompressioncodinginrecommendationG.726andaprogramofADPCMencoder.Otherwise,thisthesisdiscussedtheimplementationofADPCMdecoder.Eachalgorithmmoduleintherecommendationalgorithmhasbeenimplemented.Thispartisthekeypointinthisthesis.Wedividethealgorithmintotwomodules.Oneisadaptivequantization,andanotherisadaptiveprediction.Inadaptivequantizationalgorithm,sixsub-moduleshavebeenimplemented.TheyareInputPCMFormatConversion,DifferenceSignalComputation,QuantizerScaleFactorAdaptation,AdaptationSpeedControl,ToneAndTransitionDetectorandAdaptiveQuantizer.Inadaptivepredictionalgorithm,twosub-modules,InverseAdaptiveQuantizer,andAdaptivePredictorAndReconstructedSignalCalculator,areimplemented.Keywords:G.726Standard;ADPCM；AdaptiveQuantization；AdaptivePredicG.726标准ADPCM编码方法研究与仿真目录1引言........................................................................................................................................11.1课题背景及目的.........................................................................................................11.2国内外研究状况.........................................................................................................21.3课题研究方法.............................................................................................................21.4本文的仿真软件Matlab.............................................................................................61.5G.726标准简介.........................................................................................................61.6内容安排...................................................................................................................72ADPCM编码器的原理.......................................................................................................82.1G.726编码器算法总体概述........................................................................................82.2自适应预测语音波形编码器的设计.........................................................................83ADPCM编码器自适应量化模块的原理...........................................................................83.1输入PCM格式转换...................................................................................................93.2差分信号计算...........................................................................................................123.3自适应量化器...........................................................................................................123.4量化器定标因子自适应...........................................................................................133.5自适应速度控制........................................................................................................143.6单音和转移检测器......................................................................错误!未定义书签。4ADPCM编码器自适应预测模块的原理4.1自适应预测器和重建信号计算器...........................................................................174.2逆自适应量化器..........................................................................错误!未定义书签。5程序流程以及分析..............................................................................................................195.1encode()编码函数......................................................................................................195.2输入PCM格式转换.................................................................................................205.3差分信号计算...........................................................................................................215.4自适应量化器...........................................................................................................205.5逆自适应量化器.......................................................................................................235.6量化器定标因子自适应...........................................................................................255.7自适应速度控制.......................................................................................................265.8自适应预测器和重建信号计算器...........................................................................28G.726标准ADPCM编码方法研究与仿真5.9单音和转移检测器...................................................................................................315.10decoder()解码函数...................................................................................................306结束语...............................................................................................