《数字音频技术》PPT课件

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1、第六章数字音频技术Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.音频信号Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright200

2、4-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.6.1.1音频信号的特点1、声音信号的形式声音在物理学上称之为声波，是通过一定介质（如空气、水等）传播的一种连续振动的波。声源所引起的空气压力变化，被耳朵的耳膜所检测，然后产生电信号刺激大脑的听觉神经，从而使人们能感觉到声音的存在。语音信号：语言的物质载体，具有复杂的语法和语义，难于识别。非语音信号：音乐，自然界的声音，信息量低，识别简单。Evalua

3、tiononly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.音频信号1、声音信号的形式在自然界，声波与水波一样都是一种振动波Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0

4、.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.音频信号用声音录制软件记录的英文单词”Hello”语音的实际波形。Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspo

5、se.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.音频信号2、模拟音频信号的物理特征频率：体现音调的高低，单位Hz幅度：体现声音的强弱，单位dB谐波：体现音色的优美程度。可听频率带宽（音频）：20Hz~20kHzEvaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.N

6、ET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.音频信号频带带宽应用抽样频率窄带语音300Hz~3.4kHz3.1kHz电话通信8kHz宽带语音54Hz~7kHz7kHz电话会议、视频会议16kHz数字音频广播（ＤＡＢ）信号20Hz~15kHz15kHz声音广播和电视伴音广播32kHz高保真立体声音频信号20Hz~20kHz20kHzVCD、DVD、CD唱片、HDTV伴音44.1kHz或48kHz按声音所占频带区分音频信号：Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5C

7、lientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.音频信号2、模拟音频信号的物理特征Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5