深入淺出通信原理101-200.docx

目 錄目 錄1101.正弦信號(hào)的傅立葉變換1102.直流信號(hào)的傅立葉變換3103.復(fù)指數(shù)信號(hào)傅立葉變換的另外一種求法6104.非周期信號(hào)的傅立葉變換6105.傅立葉變換的對(duì)稱(chēng)性（一）8106.傅立葉變換的對(duì)稱(chēng)性（二）10107.傅立葉變換的對(duì)稱(chēng)性（三）11108.序列的卷積12109.序列的卷積計(jì)算過(guò)程14110.利用matlab計(jì)算序列的卷積21111.序列卷積定義中k的取值范圍22112.單位沖激和單位沖激響應(yīng)序列23113.系統(tǒng)的輸出和輸入及單位沖激響應(yīng)的關(guān)系24114.連續(xù)信號(hào)的卷積32115.卷積積分的計(jì)算過(guò)程（一）33116.卷積積分的計(jì)算過(guò)程（二）35117.卷積積分的計(jì)算過(guò)程（三）39118.卷積積分的計(jì)算過(guò)程（四）44119.卷積積分的計(jì)算過(guò)程（五）46120.與沖激函數(shù)做卷積（一）47121.與沖激函數(shù)做卷積（二）48122.與沖激函數(shù)做卷積（三）50123.與沖激函數(shù)做卷積（四）51124.傅立葉變換的時(shí)移特性53125.利用向量旋轉(zhuǎn)來(lái)理解時(shí)移特性（一）53126.利用向量旋轉(zhuǎn)理解時(shí)移特性（二）54127.時(shí)間延遲后的信號(hào)頻譜（一）55128.時(shí)間延遲后的信號(hào)頻譜（二）58129.時(shí)間延遲后的信號(hào)傅立葉變換（一）60130.時(shí)間延遲后的信號(hào)傅立葉變換（二）62131.時(shí)間延遲后的信號(hào)傅立葉變換（三）63132.時(shí)域卷積定理65133.頻域卷積定理66134.維基百科給出的頻域卷積定理證明68135.利用卷積和計(jì)算卷積積分（一）69136.利用卷積和計(jì)算卷積積分（二）71137.利用卷積和計(jì)算卷積積分（三）74138.推導(dǎo)頻域卷積定理（一）76139.推導(dǎo)頻域卷積定理（二）77140.推導(dǎo)頻域卷積定理（三）78141.頻域卷積定理的兩種形式79142.利用傅立葉變換的對(duì)稱(chēng)性證明時(shí)域卷積定理79143.利用頻域卷積定理理解調(diào)制（一）80144.利用頻域卷積定理理解調(diào)制（二）81145.利用頻域卷積定理理解采樣（一）82146.利用頻域卷積定理理解采樣（二）83147.利用頻域卷積定理理解采樣（三）84148.利用頻域卷積定理理解采樣（四）88149.實(shí)際應(yīng)用中的采樣是理想采樣嗎（一）89150.實(shí)際應(yīng)用中的采樣是理想采樣嗎（二）90151.實(shí)際應(yīng)用中的采樣是理想采樣嗎（三）91152.平頂采樣和理想采樣的關(guān)系92153.從頻域看平頂采樣（一）94154.從頻域看平頂采樣（二）95155.從頻域看平頂采樣（三）95156.從頻域看平頂采樣（四）96157.從頻域看平頂采樣（五）96158.從頻域看平頂采樣（六）98159.從頻域看平頂采樣（七）99160.采樣在通信系統(tǒng)中的應(yīng)用101161.采樣在通信系統(tǒng)中的應(yīng)用（二）101162.奈奎斯特采樣定理102163.頻率混疊現(xiàn)象104164.以特定頻率對(duì)余弦信號(hào)采樣會(huì)發(fā)生混疊（一）106165.以特定頻率對(duì)余弦信號(hào)采樣會(huì)發(fā)生混疊（二）107166.生活中頻率混疊的例子（一）108167.生活中頻率混疊的例子（二）109168.生活中頻率混疊的例子（三）109169.對(duì)復(fù)指數(shù)信號(hào)采樣發(fā)生混疊的規(guī)律110170.余弦和復(fù)指數(shù)信號(hào)采樣發(fā)生混疊的規(guī)律對(duì)比（一）111171.余弦和復(fù)指數(shù)信號(hào)采樣發(fā)生混疊的規(guī)律對(duì)比（二）111172.余弦和復(fù)指數(shù)信號(hào)采樣發(fā)生混疊的規(guī)律對(duì)比（三）112173.余弦和復(fù)指數(shù)信號(hào)采樣發(fā)生混疊的規(guī)律對(duì)比（四）114174.余弦和復(fù)指數(shù)信號(hào)采樣發(fā)生混疊的規(guī)律對(duì)比（五）115175.什么是折疊頻率116176.抗混疊濾波器118177.從避免混疊的角度推出采樣定理119178.從頻域理解由抽樣信號(hào)恢復(fù)出模擬信號(hào)119179.從時(shí)域理解由理想抽樣信號(hào)恢復(fù)出模擬信號(hào)120180.如何由平頂抽樣信號(hào)恢復(fù)出模擬信號(hào)121181.什么是帶通信號(hào)？122182.帶通信號(hào)采樣定理122183.如何推導(dǎo)出帶通采樣定理（一）123184.如何推導(dǎo)出帶通采樣定理（二）124185.如何推導(dǎo)出帶通采樣定理（三）125186.如何推導(dǎo)出帶通采樣定理（四）126187.圖解帶通采樣定理中的采樣頻率126188.圖解帶通采樣定理中的采樣頻率（二）128189.以最低采樣頻率對(duì)帶通信號(hào)進(jìn)行采樣（一）129190.以最低采樣頻率對(duì)帶通信號(hào)進(jìn)行采樣（二）130191.以最低采樣頻率對(duì)IQ調(diào)制信號(hào)進(jìn)行采樣131192.帶通采樣定理和奈奎斯特采樣定理的關(guān)系132193.帶通信號(hào)采樣前的抗混疊濾波器133194.帶通采樣定理規(guī)定的采樣頻率是最低的嗎（一）134195.帶通采樣定理給出的采樣頻率是最低的嗎（二）135196.帶通采樣定理給出的采樣頻率是最低的嗎（三）136197.帶通采樣定理給出的采樣頻率是最低的嗎（四）137198.帶通采樣定理給出的采樣頻率是最低的嗎（五）138199.什么是相139200.什么是相位（一）142III101. 正弦信號(hào)的傅立葉變換 f=1; subplot(1,2,1); t=-5:0.001:5; x=sin(2*pi*f*t); plot3(x,t,0*t); xlabel(x); ylabel(t); zlabel(y); set(gca,YDir,reverse); grid on; title(sinomega_0t的波形); subplot(1,2,2); xlabel(x); ylabel(omega); zlabel(y); axis(-10 10 -10 10 -10 10); set(gca,YDir,reverse); grid on; arrow3d(0,2*pi*f,0,0,2*pi*f, -1*pi,10, cylinder,0.3,0.5); arrow3d(0,-2*pi*f,0,0, -2*pi*f, 1*pi,10, cylinder,0.3,0.5); title(sinomega_0t的傅立葉變換); line(0 0,-10 10,0 0);102. 直流信號(hào)的傅立葉變換 subplot(1,2,1); t=-1.5:0.001:1.5; y=rectpuls(t,4); plot(t,y) axis(-1.5 1.5 -0.5 1.5); xlabel(time);ylabel(magnitude); grid on subplot(1,2,2); f=-4*2*pi:0.001:4*2*pi; xlabel(omega);ylabel(magnitude); axis(-4*2*pi 4*2*pi -0.5 1.5); grid on arrow(0,0,0,1); gtext(2pidelta(omega);2010-7-26 23:08 上傳下載附件 (50.77 KB) subplot(2,2,1); t=-1.5:0.001:1.5; y=rectpuls(t,1); plot(t,y) axis(-1.5 1.5 -0.5 2.5); grid on subplot(2,2,2); f=-4:0.001:4; X=sinc(f); plot(f,X) axis(-4 4 -0.5 2.5); grid on subplot(2,2,3); t=-1.5:0.001:1.5; y=rectpuls(t,2); plot(t,y) axis(-1.5 1.5 -0.5 2.5); grid on subplot(2,2,4); f=-4:0.001:4; X=2*sinc(2*f); plot(f,X) axis(-4 4 -0.5 2.5); grid on2010-7-26 23:08 上傳下載附件 (25.63 KB) 2010-7-26 23:08 上傳下載附件 (27.3 KB) 103. 復(fù)指數(shù)信號(hào)傅立葉變換的另外一種求法104. 非周期信號(hào)的傅立葉變換105. 傅立葉變換的對(duì)稱(chēng)性（一） subplot(2,2,1); t=-1.5:0.001:1.5; y=rectpuls(t,4); plot(t,y) axis(-1.5 1.5 -0.5 1.5); grid on subplot(2,2,2); f=-4*2*pi:0.001:4*2*pi; axis(-4*2*pi 4*2*pi -0.5 1.5); grid on arrow(0,0,0,1); subplot(2,2,4); t=-1.5:0.001:1.5; y=rectpuls(t,4); plot(t,y) axis(-1.5 1.5 -0.5 1.5); grid on subplot(2,2,3); f=-4*2*pi:0.001:4*2*pi; axis(-4*2*pi 4*2*pi -0.5 1.5); grid on arrow(0,0,0,1);106. 傅立葉變換的對(duì)稱(chēng)性（二）107. 傅立葉變換的對(duì)稱(chēng)性（三）108. 序列的卷積109. 序列的卷積計(jì)算過(guò)程% x(n) subplot(2,1,1); n=-12:1:12; x=0 0 0 0 0 0 0 0 0 0 0 0 1 1.2 0.8 -0.7 -0.5 0.4 1.4 0 0 0 0 0 0; stem(n,x); xlabel(n);ylabel(x);title(x(n) );% h(n) subplot(2,1,2); h=0 0 0 0 0 0 0 0 0 0 0 0 1 0.8 -0.5 -0.3 0 0 0 0 0 0 0 0 0; n=-12:1:12; stem(n,h) xlabel(n);ylabel(h);title(h(n) );2010-8-2 22:21 上傳下載附件 (34.46 KB) 2010-8-2 22:21 上傳下載附件 (12.86 KB) 2010-8-2 22:21 上傳下載附件 (39.73 KB) 2010-8-2 22:21 上傳下載附件 (6.68 KB) 2010-8-2 22:21 上傳下載附件 (39.55 KB) 2010-8-2 22:21 上傳下載附件 (8.08 KB) 2010-8-2 22:21 上傳下載附件 (40.42 KB) 2010-8-2 22:21 上傳下載附件 (9.32 KB) 2010-8-2 22:21 上傳下載附件 (38.53 KB) 2010-8-2 22:21 上傳下載附件 (13.52 KB) 2010-8-2 22:21 上傳下載附件 (39.53 KB) 110. 利用matlab計(jì)算序列的卷積% x(n) subplot(3,1,1); n=0:1:6; x=1 1.2 0.8 -0.7 -0.5 0.4 1.4; stem(n,x); xlabel(n);ylabel(x);title(x(n) ); axis(-12 12 -2.5 2.5);% h(n) subplot(3,1,2); h=1 0.8 -0.5 -0.3; n=0:1:3; stem(n,h) xlabel(n);ylabel(h);title(h(n) ); axis(-12 12 -2.5 2.5);% x(n)*h(n) subplot(3,1,3); y=conv(x,h); n=0:1:9; stem(n,y) xlabel(n);ylabel(y);title(y(n)=x(n)*h(n) ); axis(-12 12 -2.5 2.5);111. 序列卷積定義中k的取值范圍112. 單位沖激和單位沖激響應(yīng)序列113. 系統(tǒng)的輸出和輸入及單位沖激響應(yīng)的關(guān)系2010-4-9 22:54 上傳下載附件 (19.36 KB) 114. 連續(xù)信號(hào)的卷積115. 卷積積分的計(jì)算過(guò)程（一）% x(t) 矩形脈沖 subplot(2,1,1); t=-3:0.001:6; x=rectpuls(t-2,2); plot(t,x); xlabel(t);ylabel(x(t);% h(t) 鋸齒脈沖 subplot(2,1,2); t=-3:0.001:6; h= (0.5*sawtooth(2*pi*0.5*t)+0.5).*rectpuls(t-1,2); plot(t,h); xlabel(t);ylabel(h(t);% x() subplot(2,1,1); tau=-3:0.001:6; x=rectpuls(tau-2,2); plot(tau,x); xlabel(tau);ylabel(x(tau);% h(-) subplot(2,1,2); tau=-3:0.001:6; h=(0.5-0.5*sawtooth(2*pi*0.5*tau) ).*rectpuls(tau+1,2); plot(tau,h); xlabel(tau);ylabel(h(-tau);注意：tau，不是tao。116. 卷積積分的計(jì)算過(guò)程（二）% x() subplot(2,1,1); tau=-3:0.001:6; x=rectpuls(tau-2,2); plot(tau,x); xlabel(tau);ylabel(x(tau);% h(t-) ，t=1 subplot(2,1,2); t=1; tau=-3:0.001:6; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); hold on; h1=(0.5-0.5*sawtooth(2*pi*0.5*tau) ).*rectpuls(tau+1,2); plot(tau,h1, :); xlabel(tau);ylabel(h(t-tau);% x() subplot(2,1,1); tau=-3:0.001:6; x=rectpuls(tau-2,2); plot(tau,x); xlabel(tau);ylabel(x(tau);% h(t-) ，t=2 subplot(2,1,2); t=2; tau=-3:0.001:6; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); hold on; h1=(0.5-0.5*sawtooth(2*pi*0.5*tau) ).*rectpuls(tau+1,2); plot(tau,h1, :); xlabel(tau);ylabel(h(t-tau);% x() subplot(2,1,1); tau=-3:0.001:6; x=rectpuls(tau-2,2); plot(tau,x); xlabel(tau);ylabel(x(tau);% h(t-)，t=3 subplot(2,1,2); t=3; tau=-3:0.001:6; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); hold on; h1=(0.5-0.5*sawtooth(2*pi*0.5*tau) ).*rectpuls(tau+1,2); plot(tau,h1, :); xlabel(tau);ylabel(h(t-tau);% x() subplot(2,1,1); tau=-3:0.001:6; x=rectpuls(tau-2,2); plot(tau,x); xlabel(tau);ylabel(x(tau);% h(t-)，t=4 subplot(2,1,2); t=4; tau=-3:0.001:6; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); hold on; h1=(0.5-0.5*sawtooth(2*pi*0.5*tau) ).*rectpuls(tau+1,2); plot(tau,h1, :); xlabel(tau);ylabel(h(t-tau);% x() subplot(2,1,1); tau=-3:0.001:6; x=rectpuls(tau-2,2); plot(tau,x); xlabel(tau);ylabel(x(tau);% h(t-)，t=5 subplot(2,1,2); t=5; tau=-3:0.001:6; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); hold on; h1=(0.5-0.5*sawtooth(2*pi*0.5*tau) ).*rectpuls(tau+1,2); plot(tau,h1, :); xlabel(tau);ylabel(h(t-tau);117. 卷積積分的計(jì)算過(guò)程（三） tau=-3:0.001:6; subplot(7,1,1); x=rectpuls(tau-2,2); plot(tau,x); xlabel(tau);ylabel(x(tau); subplot(7,1,2); t=0; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); xlabel(tau);ylabel(h(t-tau); subplot(7,1,3); t=1; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); xlabel(tau);ylabel(h(t-tau); subplot(7,1,4); t=2; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); xlabel(tau);ylabel(h(t-tau); subplot(7,1,5); t=3; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); xlabel(tau);ylabel(h(t-tau); subplot(7,1,6); t=4; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); xlabel(tau);ylabel(h(t-tau); subplot(7,1,7); t=5; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); xlabel(tau);ylabel(h(t-tau); tau=-3:0.001:6; subplot(7,2,1); x=rectpuls(tau-2,2); plot(tau,x); xlabel(tau);ylabel(x(tau); axis(-3 6 0 1); subplot(7,2,2); h= (0.5*sawtooth(2*pi*0.5*tau)+0.5).*rectpuls(tau-1,2); plot(tau,h); xlabel(tau);ylabel(h(tau); axis(-3 6 0 1); subplot(7,2,3); t=0; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); xlabel(tau);ylabel(h(t-tau); axis(-3 6 0 1); subplot(7,2,4); t=0; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2).*x; plot(tau,h); xlabel(tau);ylabel(x(tau)h(t-tau); axis(-3 6 0 1); subplot(7,2,5); t=1; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); xlabel(tau);ylabel(h(t-tau); axis(-3 6 0 1); subplot(7,2,6); t=1; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2).*x; plot(tau,h); xlabel(tau);ylabel(x(tau)h(t-tau); axis(-3 6 0 1); subplot(7,2,7); t=2; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); xlabel(tau);ylabel(x(tau)h(t-tau); axis(-3 6 0 1); subplot(7,2,8); t=2; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2).*x; ha=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,x,: ,tau,ha, : , tau,h); xlabel(tau);ylabel(x(tau)h(t-tau); axis(-3 6 0 1); subplot(7,2,9); t=3; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); xlabel(tau);ylabel(x(tau)h(t-tau); axis(-3 6 0 1); subplot(7,2,10); t=3; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2).*x; ha=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h,tau,x,: ,tau,ha, : ); plot(tau,x,: ,tau,ha, : , tau,h); axis(-3 6 0 1); subplot(7,2,11); t=4; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); xlabel(tau);ylabel(x(tau)h(t-tau); axis(-3 6 0 1); subplot(7,2,12); t=4; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2).*x; ha=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,x,: ,tau,ha, : , tau,h); xlabel(tau);ylabel(x(tau)h(t-tau); axis(-3 6 0 1); subplot(7,2,13); t=5; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2); plot(tau,h); xlabel(tau);ylabel(x(tau)h(t-tau); axis(-3 6 0 1); subplot(7,2,14); t=5; h=(0.5-0.5*sawtooth(2*pi*0.5*(tau-t) ).*rectpuls(tau-t+1,2).*x; plot(tau,h); xlabel(tau);ylabel(x(tau)h(t-tau); axis(-3 6 0 1);118. 卷積積分的計(jì)算過(guò)程（四）% x(t) 矩形脈沖 subplot(3,1,1); t=-3:0.001:6; x=rectpuls(t-2,2); plot(t,x); xlabel(t);ylabel(x(t); axis(-3 6 0 1);% h(t) 鋸齒脈沖 subplot(3,1,2); t=-3:0.001:6; h= (0.5*sawtooth(2*pi*0.5*t)+0.5).*rectpuls(t-1,2); plot(t,h); xlabel(t);ylabel(h(t); axis(-3 6 0 1);% x(t)*h(t) 卷積結(jié)果 subplot(3,1,3); t=-3:0.001:1; y1=0*t; plot(t,y1); hold on; t=1:0.001:3; y2=0.25.* (t-1).*(t-1); plot(t,y2); t=3:0.001:5; y3=0.25.*(t-1).*(5-t); plot(t,y3); xlabel(t);ylabel(x(t)*h(t); axis(-3 6 0 1);119. 卷積積分的計(jì)算過(guò)程（五）120. 與沖激函數(shù)做卷積（一） t=-5:0.001:5; subplot(3,1,1); f=(1-0.1*sin(2*pi*t).*rectpuls(t,1); plot(t,f); axis(-5 5 0 1.5); xlabel(t);ylabel(f(t); subplot(3,1,2); axis(-5 5 0 1.5); arrow(0,0,0,1); xlabel(t);ylabel(delta(t); subplot(3,1,3); f=(1-0.1*sin(2*pi*t).*rectpuls(t,1); plot(t,f); axis(-5 5 0 1.5); xlabel(t);ylabel(f(t)*delta(t);121. 與沖激函數(shù)做卷積（二） t=-5:0.001:5; subplot(4,1,1); f=(1-0.1*sin(2*pi*t).*rectpuls(t,1); plot(t,f); axis(-5 5 0 1.5); xlabel(t);ylabel(f(tau); subplot(4,1,2); axis(-5 5 0 1.5); arrow(0.3,0,0.3,1); xlabel(t);ylabel(delta(t-tau); subplot(4,1,3); f=(1-0.1*sin(2*pi*t).*rectpuls(t,1); plot(t,f, :); axis(-5 5 0 1.5); t=0.3; ft=(1-0.1*sin(2*pi*t).*rectpuls(t,1); arrow(0.3,0,0.3,ft); xlabel(t);ylabel(f(tau)delta(t-tau); subplot(4,1,4); t=0.3; ft=(1-0.1*sin(2*pi*t).*rectpuls(t,1); plot(0.3,ft, o); hold on ; t=-5:0.001:5; f=(1-0.1*sin(2*pi*t).*rectpuls(t,1); plot(t,f, :); axis(-5 5 0 1.5); xlabel(t);ylabel(f(t);122. 與沖激函數(shù)做卷積（三） t=-5:0.001:5; subplot(3,1,1); f=(1-0.1*sin(2*pi*t).*rectpuls(t,1); plot(t,f); axis(-5 5 0 1.5); xlabel(t);ylabel(f(t); subplot(3,1,2); axis(-5 5 0 1.5); arrow(3,0,3,1); xlabel(t);ylabel(delta(t-t_0); subplot(3,1,3); f=(1-0.1*sin(2*pi*t).*rectpuls(t-3,1); plot(t,f); axis(-5 5 0 1.5); xlabel(t);ylabel(f(t)*delta(t-t_0);123. 與沖激函數(shù)做卷積（四） omega=-5:0.001:5; subplot(3,2,1); F=sinc(2*omega).*rectpuls(omega,1); plot(omega,F); axis(-5 5 0 1.5); xlabel(omega);ylabel(F(omega); subplot(3,2,2); F=sinc(2*omega).*rectpuls(omega,1); plot(omega,F); axis(-5 5 0 1.5); xlabel(omega);ylabel(F(omega);% 00 subplot(3,2,3); axis(-5 5 0 1.5); arrow(3,0,3,1); xlabel(omega);ylabel(delta(omega-omega_0);% 0 subplot(3,2,4); axis(-5 5 0 1.5); arrow(-3,0,-3,1); xlabel(omega);ylabel(delta(omega-omega_0); subplot(3,2,5); F=sinc(2*(omega-3).*rectpuls(omega-3,1); plot(omega,F); axis(-5 5 0 1.5); xlabel(omega);ylabel(F(omega)*delta(omega-omega_0); subplot(3,2,6); F=sinc(2*(omega+3).*rectpuls(omega+3,1); plot(omega,F); axis(-5 5 0 1.5); xlabel(omega);ylabel(F(omega)*delta(omega-omega_0);124. 傅立葉變換的時(shí)移特性125. 利用向量旋轉(zhuǎn)來(lái)理解時(shí)移特性（一）126. 利用向量旋轉(zhuǎn)理解時(shí)移特性（二）127. 時(shí)間延遲后的信號(hào)頻譜（一）% f(t) t=-1.5:0.001:1.5; y=rectpuls(t,1); subplot(2,1,1);plot(t,y) axis(-1.5 1.5 -0.5 1.5); grid on% f(t-t0) t=-1.5:0.001:1.5; y=rectpuls(t-0.1,1); subplot(2,1,2);plot(t,y) axis(-1.5 1.5 -0.5 1.5); grid on% f(t)的頻譜 f=-4:0.2:4; X=sinc(f); xlabel(x); ylabel(omega); zlabel(y); axis(-1.5 1.5 -4 4 -1.5 1.5); set(gca,YDir,reverse); grid on; hold on; for i=1:41 line(0,X(i),f(i),f(i),0,0); end line(0 0,-4 4,0 0);% f(t-t0)的頻譜 f=-4:0.2:4; t0=0.1; X=sinc(f).*exp(-i*2*pi*f*t0); x=real(X); y=imag(X); xlabel(x); ylabel(omega); zlabel(y); axis(-1.5 1.5 -4 4 -1.5 1.5); set(gca,YDir,reverse); grid on; hold on; for i=1:41 line(0,x(i),f(i),f(i),0,y(i); end line(0 0,-4 4,0 0);128. 時(shí)間延遲后的信號(hào)頻譜（二） f=-4:0.2:4; X=abs(sinc(f); stem(f,X); hold on; f=-4:0.01:4; X=abs(sinc(f); plot(f,X, : )129. 時(shí)間延遲后的信號(hào)傅立葉變換（一）130. 時(shí)間延遲后的信號(hào)傅立葉變換（二）131. 時(shí)間延遲后的信號(hào)傅立葉變換（三）% x(t)的頻譜 f=-4:0.001:4; X=sinc(f); xlabel(x); ylabel(f); zlabel(y); plot3(X,f,0*f); grid on; line(0 0,-4 4,0 0); axis(-1.5 1.5 -4 4 -1.5 1.5); set(gca,YDir,reverse);% x(t-t0)的頻譜 f=-4:0.001:4; t0=0.1; X=sinc(f).*exp(-i*2*pi*f*t0); x=real(X); y=imag(X); xlabel(x); ylabel(f); zlabel(y); plot3(x,f,y); grid on; line(0 0,-4 4,0 0); axis(-1.5 1.5 -4 4 -1.5 1.5); set(gca,YDir,reverse);132. 時(shí)域卷積定理133. 頻域卷積定理134. 維基百科給出的頻域卷積定理證明135. 利用卷積和計(jì)算卷積積分（一）136. 利用卷積和計(jì)算卷積積分（二）137. 利用卷積和計(jì)算卷積積分（三） t=-3:0.001:1; y1=0*t; plot(t,y1); hold on; t=1:0.001:3; y2=0.25.* (t-1).*(t-1); plot(t,y2); t=3:0.001:5; y3=0.25.*(t-1).*(5-t); plot(t,y3); xlabel(t);ylabel(x(t)*h(t); axis(-3 6 0 1); t=1:0.2:3; %delta=0.2 x=rectpuls(t-2,2); t=0:0.2:2; %delta=0.2 h= (0.5*sawtooth(2*pi*0.5*t)+0.5).*rectpuls(t-1,2); t=1:0.2:5; %delta=0.2 c=0