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<div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62925b11e74b9677e8d94831/bg1.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x1 h3 y2 ff1 fs0 fc0 sc0 ls0 ws0">《数字信号处理》</div><div class="t m0 x2 h4 y3 ff1 fs1 fc0 sc0 ls0 ws0">课程大作业</div><div class="t m0 x3 h5 y4 ff1 fs2 fc0 sc1 ls0 ws0">班级：</div><div class="t m0 x3 h5 y5 ff1 fs2 fc0 sc1 ls0 ws0">学号：</div><div class="t m0 x3 h5 y6 ff1 fs2 fc0 sc1 ls0 ws0">姓名：</div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div>
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<div id="pf2" class="pf w0 h0" data-page-no="2"><div class="pc pc2 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62925b11e74b9677e8d94831/bg2.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x4 h6 y7 ff1 fs3 fc1 sc0 ls0 ws0">目录</div><div class="t m0 x4 h7 y8 ff1 fs4 fc0 sc0 ls0 ws0">一、设计目的<span class="_ _0"> </span>3</div><div class="t m0 x4 h7 y9 ff1 fs4 fc0 sc0 ls0 ws0">二、设计要求<span class="_ _0"> </span>3</div><div class="t m0 x4 h7 ya ff1 fs4 fc0 sc0 ls0 ws0">三、设计步骤、实现方法、结果分析<span class="_ _1"> </span>3</div><div class="t m0 x5 h7 yb ff1 fs4 fc0 sc0 ls0 ws0">1、时域采样<span class="_ _2"> </span>3</div><div class="t m0 x5 h7 yc ff1 fs4 fc0 sc0 ls0 ws0">2、数字低通滤波器设计<span class="_ _3"> </span>6</div><div class="t m0 x5 h7 yd ff1 fs4 fc0 sc0 ls0 ws0">3、数字高通滤波器设计<span class="_ _3"> </span>9</div><div class="t m0 x5 h7 ye ff1 fs4 fc0 sc0 ls0 ws0">4、合成噪声<span class="_ _2"> </span>11</div><div class="t m0 x5 h7 yf ff1 fs4 fc0 sc0 ls0 ws0">5、数字滤波器设计<span class="_ _4"> </span>12</div><div class="t m0 x4 h7 y10 ff1 fs4 fc0 sc0 ls0 ws0">四、心得体会<span class="_ _0"> </span>15</div><div class="t m0 x4 h7 y11 ff1 fs4 fc0 sc0 ls0 ws0">五、完整代码<span class="_ _0"> </span>16</div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div>
<div id="pf3" class="pf w0 h0" data-page-no="3"><div class="pc pc3 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62925b11e74b9677e8d94831/bg3.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x4 h8 y12 ff1 fs5 fc0 sc1 ls0 ws0">一、<span class="_ _5"> </span>设计目的</div><div class="t m0 x6 h7 y13 ff2 fs4 fc0 sc0 ls0 ws0">1<span class="ff1 sc1">、<span class="_ _6"> </span><span class="sc0">学会<span class="_ _7"> </span><span class="ff3">MA<span class="_ _8"></span>TLAB<span class="_ _9"> </span><span class="ff1">的使用，掌握<span class="_ _7"> </span></span>MA<span class="_ _8"></span>TLAB<span class="_ _7"> </span><span class="ff1">程序设计方法；</span></span></span></span></div><div class="t m0 x6 h7 y14 ff2 fs4 fc0 sc0 ls0 ws0">2<span class="ff1 sc1">、<span class="_ _6"> </span><span class="sc0">掌握使用<span class="_ _7"> </span><span class="ff3">MA<span class="_ _8"></span>TLAB<span class="_ _9"> </span><span class="ff1">对语言信号采集的方法；</span></span></span></span></div><div class="t m0 x6 h7 y15 ff2 fs4 fc0 sc0 ls0 ws0">3<span class="ff1 sc1">、<span class="_ _6"> </span><span class="sc0">掌握数字信号处理的基本概念、基本理论和基本方法；</span></span></div><div class="t m0 x6 h7 y16 ff2 fs4 fc0 sc0 ls0 ws0">4<span class="ff1 sc1">、<span class="_ _6"> </span><span class="sc0">掌握<span class="_ _7"> </span><span class="ff3">MA<span class="_ _8"></span>TLAB<span class="_ _9"> </span><span class="ff1">设计<span class="_ _7"> </span></span>IIR<span class="_ _7"> </span><span class="ff1">数字滤波器的设计方法；</span></span></span></span></div><div class="t m0 x6 h7 y17 ff2 fs4 fc0 sc0 ls0 ws0">5<span class="ff1 sc1">、<span class="_ _6"> </span><span class="sc0">学会用<span class="_ _7"> </span><span class="ff3">MA<span class="_ _8"></span>TLAB<span class="_ _9"> </span><span class="ff1">对信号进行分析和处理。</span></span></span></span></div><div class="t m0 x4 h8 y18 ff1 fs5 fc0 sc1 ls0 ws0">二、<span class="_ _5"> </span>设计要求</div><div class="t m0 x6 h7 y19 ff2 fs4 fc0 sc0 ls0 ws0">1<span class="ff1 sc1">、<span class="_ _6"> </span><span class="sc0">使用手机录制一段自我介绍音频，命名为“<span class="ff3">.wav”</span>。</span></span></div><div class="t m0 x6 h7 y1a ff2 fs4 fc0 sc0 ls0 ws0">2<span class="ff1 sc1">、<span class="_ _6"> </span><span class="sc0">利用<span class="_ _7"> </span><span class="ff3">Matlab<span class="_ _7"> </span></span>软件对“<span class="ff3">.wav”</span>音频信号进行数字信号采样，分别对</span></span></div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div>
<div id="pf4" class="pf w0 h0" data-page-no="4"><div class="pc pc4 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62925b11e74b9677e8d94831/bg4.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x7 h7 y1b ff1 fs4 fc0 sc0 ls0 ws0">采样后的信号进行时<span class="ff3">/</span>频域分析，并提供仿真图（包括语音信号的</div><div class="t m0 x7 h7 y1c ff1 fs4 fc0 sc0 ls0 ws0">时域波形和频谱图）和分析说明；</div><div class="t m0 x6 h7 y1d ff2 fs4 fc0 sc0 ls0 ws0">3<span class="ff1 sc1">、<span class="_ _6"> </span><span class="sc0">设计数字滤波器，对“学号<span class="ff3">.wav”</span>音频信号分别进行低通滤波（截</span></span></div><div class="t m0 x7 h7 y1e ff1 fs4 fc0 sc0 ls0 ws0">止频率<span class="_ _7"> </span><span class="ff3">4000Hz</span>，阻带衰减<span class="_ _7"> </span><span class="ff3">20dB</span>，过渡带宽<span class="_ _7"> </span><span class="ff3">0.1<span class="ff4"></span></span>）与高通滤波</div><div class="t m0 x7 h7 y1f ff1 fs4 fc0 sc0 ls0 ws0">（截止频率<span class="_ _7"> </span><span class="ff3">3000Hz</span>，阻带衰减<span class="_ _7"> </span><span class="ff3">40dB</span>，过渡带宽<span class="_ _7"> </span><span class="ff3">0.1<span class="ff4"></span></span>），提供</div><div class="t m0 x7 h7 y20 ff1 fs4 fc0 sc0 ls0 ws0">时<span class="ff3">/</span>频域仿真图（包括所设计滤波器的损耗函数曲线以及滤波后的</div><div class="t m0 x7 h7 y21 ff1 fs4 fc0 sc0 ls0 ws0">频谱图）和分析说明；</div><div class="t m0 x6 h7 y22 ff2 fs4 fc0 sc0 ls0 ws0">4<span class="ff1 sc1">、<span class="_ _6"> </span><span class="sc0">给“<span class="ff3">.wav”</span>添加一段幅度大小为<span class="_ _7"> </span><span class="ff3">0.1</span>，频率<span class="_ _7"> </span><span class="ff3">f<span class="_ _7"> </span></span>为<span class="_ _7"> </span><span class="ff3">9000Hz<span class="_ _7"> </span></span>的正弦噪</span></span></div><div class="t m0 x7 h7 y23 ff1 fs4 fc0 sc0 ls0 ws0">声，合成一段有噪声的音频，统一命名为“<span class="ff3">noisy_signal.wav”</span>。</div><div class="t m0 x7 h7 y24 ff1 fs4 fc0 sc0 ls0 ws0">对添加噪声后的信号进行时<span class="ff3">/</span>频域分析，并提供仿真图（包括语音</div><div class="t m0 x7 h7 y25 ff1 fs4 fc0 sc0 ls0 ws0">信号的时域波形和频谱图）和分析说明；</div><div class="t m0 x6 h7 y26 ff2 fs4 fc0 sc0 ls0 ws0">5<span class="ff1 sc1">、<span class="_ _6"> </span><span class="sc0">设计合理的数字滤波器，滤去音频信号中的噪声，提供时<span class="ff3">/</span>频域仿</span></span></div><div class="t m0 x7 h7 y27 ff1 fs4 fc0 sc0 ls0 ws0">真图（包括所设计滤波器的损耗函数曲线以及滤波后的频谱图）</div><div class="t m0 x7 h7 y28 ff1 fs4 fc0 sc0 ls0 ws0">和分析说明，并将数字滤波后的数字信号转换成<span class="_ _7"> </span><span class="ff3">wav<span class="_ _7"> </span></span>格式音频文</div><div class="t m0 x7 h7 y29 ff1 fs4 fc0 sc0 ls0 ws0">件，统一命名为<span class="_ _7"> </span><span class="ff3">denoised.wav</span>。</div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div>
<div id="pf5" class="pf w0 h0" data-page-no="5"><div class="pc pc5 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62925b11e74b9677e8d94831/bg5.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x4 h8 y2a ff1 fs5 fc0 sc1 ls0 ws0">三、<span class="_ _5"> </span>设计步骤、实现方法、结果分析</div><div class="t m0 x6 h7 y2b ff2 fs4 fc0 sc0 ls0 ws0">1<span class="ff1 sc1">、<span class="_ _6"> </span>时域采样</span></div><div class="t m0 x7 h7 y2c ff1 fs4 fc0 sc1 ls0 ws0">（<span class="ff2 sc0">1</span>）<span class="_"> </span>设计流程</div><div class="t m0 x8 h7 y2d ff1 fs4 fc0 sc0 ls0 ws0">利用‘<span class="ff3">audiore<span class="_ _a"></span>ad’<span class="ff1">函数对录制的‘</span>xx.wav’<span class="ff1">音</span></span></div><div class="t m0 x7 h7 y2e ff1 fs4 fc0 sc0 ls0 ws0">频文件进行采样，调用格式为</div><div class="t m0 x9 h9 y2f ff5 fs6 fc0 sc0 ls0 ws0">[voice,fs]=audioread(<span class="fc2">'xx.wav'</span>);%<span class="ff1">声音读取</span></div><div class="t m0 x7 h7 y30 ff1 fs4 fc0 sc0 ls0 ws0">采样后的采样值保存为‘<span class="ff3">voice’</span>，‘<span class="ff3">fs’</span>为采样频率，得到</div><div class="t m0 x7 h7 y31 ff1 fs4 fc0 sc0 ls0 ws0">‘<span class="ff3">fs=48000’;voice<span class="_ _7"> </span></span>中包含两个声道，将两个声道的音频分别提 </div><div class="t m0 x7 h7 y32 ff1 fs4 fc0 sc0 ls0 ws0">取出来，保存为‘<span class="ff3">v1’‘v2’</span>。对‘<span class="ff3">voice’‘v1’‘v2’</span>进行快速傅里叶变换，</div><div class="t m0 x7 h7 y33 ff1 fs4 fc0 sc0 ls0 ws0">并绘制出时域波形和频谱。</div><div class="t m0 x7 h7 y34 ff1 fs4 fc0 sc1 ls0 ws0">（<span class="ff2 sc0">2</span>）<span class="_"> </span>实现方式</div><div class="t m0 xa h9 y35 ff5 fs6 fc3 sc0 ls0 ws0">1.<span class="_ _b"> </span><span class="fc0">%%<span class="ff1">声音读取 </span></span></div><div class="t m0 xa h9 y36 ff5 fs6 fc3 sc0 ls0 ws0">2.<span class="_ _b"> </span><span class="fc0">[voice,fs]=audioread(<span class="fc2">'xx.wav'</span>);%<span class="ff1">声音读取 </span></span></div><div class="t m0 xa h9 y37 ff5 fs6 fc3 sc0 ls0 ws0">3.<span class="_ _b"> </span><span class="fc0">v1=voice(:,1);<span class="_ _a"></span>%<span class="ff1">抽取第一声道 </span></span></div><div class="t m0 xa h9 y38 ff5 fs6 fc3 sc0 ls0 ws0">4.<span class="_ _b"> </span><span class="fc0">v2=voice(:,2);<span class="_ _a"></span>%<span class="ff1">抽取第二声道 </span></span></div><div class="t m0 xa h9 y39 ff5 fs6 fc3 sc0 ls0 ws0">5.<span class="_ _b"> </span><span class="fc0">%sound(voice,fs);<span class="_ _a"></span>%<span class="ff1">立体声音播放 </span></span></div><div class="t m0 xa h9 y3a ff5 fs6 fc3 sc0 ls0 ws0">6.<span class="_ _b"> </span><span class="fc0">%sound(v1,fs);<span class="_ _a"></span>%<span class="ff1">播放第一声道 </span></span></div><div class="t m0 xa h9 y3b ff5 fs6 fc3 sc0 ls0 ws0">7.<span class="_ _b"> </span><span class="fc0">%sound(v2,fs);<span class="_ _a"></span>%<span class="ff1">播放第二声道 </span></span></div><div class="t m0 xa ha y3c ff5 fs6 fc3 sc0 ls0 ws0">8.<span class="_ _b"> </span><span class="fc0"></span></div><div class="t m0 xa h9 y3d ff5 fs6 fc3 sc0 ls0 ws0">9.<span class="_ _b"> </span><span class="fc0">%%<span class="ff1">傅里叶变换 </span></span></div><div class="t m0 xa h9 y3e ff5 fs6 fc3 sc0 ls0 ws0">10.<span class="_ _c"> </span><span class="fc0">fft1=fft(voice,N)/N;%<span class="_ _a"></span>voice%<span class="ff1">傅里叶变换 </span></span></div><div class="t m0 xa h9 y3f ff5 fs6 fc3 sc0 ls0 ws0">11.<span class="_ _c"> </span><span class="fc0">mag1=abs(fftshift(fft1));%<span class="_ _a"></span><span class="ff1">取模 </span></span></div><div class="t m0 xa h9 y40 ff5 fs6 fc3 sc0 ls0 ws0">12.<span class="_ _c"> </span><span class="fc0">f1=(-N/2:1:N/2-1)'*fs/N;%<span class="_ _a"></span><span class="ff1">双边变换 </span></span></div><div class="t m0 xa ha y41 ff5 fs6 fc3 sc0 ls0 ws0">13.<span class="_ _c"> </span><span class="fc0"></span></div><div class="t m0 xa h9 y42 ff5 fs6 fc3 sc0 ls0 ws0">14.<span class="_ _c"> </span><span class="fc0">fft2=fft(v1,N)/N;<span class="_ _a"></span>%v1%<span class="ff1">傅里叶变换 </span></span></div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div>
