數(shù)字信號(hào)處理所有實(shí)例及實(shí)驗(yàn)程序

1、6頁(yè)正弦曲線n=-5:5;x=inline('sin(pi*n/5',x=sin(pi*n/5,% subplot(2,2,1,stem(n,x,'r'line(-5 6,0 0axis(-5,6,-1.2,1.2xlabel('n'ylabel('x(n'14 頁(yè),卷積xn=1 1 1 1 ;hn=1 1 1 1;yn=conv(xn,hnstem(yn14頁(yè)functiony,ny=convu(h,nh,x,nx nys=nh(1+nx(1;nyf=nh(end+nx(end;y=conv(h,x;ny=nys:nyf;調(diào)用h

2、=ones(1,5;nh=-2:2;x=h;nx=nh;y,ny=convu(h,nh,x,nxsubplot(2,1,1;stem(ysubplot(2,1,2;stem(ny21頁(yè)程序和仿真圖a=0.8;ys=1;xn=1,zeros(1,30B=1;A=1,-a;xi=filtic(B,A,ys;yn=filter(B,A,xn,xi;n=0:length(yn-1;subplot(2,1,1;stem(n,yn,'.'title('(a'xlabel('n'ylabel('y(n'grid onys=0;xi=filtic

3、(B,A,ys;yn=filter(B,A,xn,xi;n=0:length(yn-1;subplot(2,1,2; stem(n,yn,'.'title('(b'xlabel('n'ylabel('h(n'axis(0,30,0,2 ;grid on6263頁(yè)function stab(Adisp('系統(tǒng)極點(diǎn)為'P=roots(Adisp('系統(tǒng)極點(diǎn)莫的最大值為'M=max(abs(Pif M<1 disp('系統(tǒng)穩(wěn)定'elsedisp('系統(tǒng)不穩(wěn)定'end調(diào)

4、用A=2 -2.98 0.17 2.3418 -1.5147, stab(A66頁(yè)B=1 0 0 0 0 0 0 0 0 - 1 ;A=1;subplot(2,2,1;zplane(B,A;H,w=freqz(B,A;subplot(2,2,2;plot(w/pi,abs(H;xlabel('omega/pi'ylabel('|H(ejomega|'axis(0,1,0,2.5;subplot(2,2,4;plot(w/pi,angle(H;xlabel('omega/pi'ylabel('phi(omega'% 69頁(yè)a=0.2

5、;B=1 0 0 0 0 0 0 0 0 -1 ;A=1 0 0 0 0 0 0 0 0 ,-a; subplot(2,2,1;zplane(B,A;title('(a零極點(diǎn)分布(¨a=0.2,N=8 'Hk,w=freqz(B,A,1024;subplot(2,2,2;plot(w/pi,abs(Hk/max(abs(Hk;xlabel('omega/pi'ylabel('|H(ejomega|'axis(0,1,0,1.5;title('(b·幅頻特性(a=0.2,N=8' a=0.9;B=1 0 0 0

6、0 0 0 0 0 -1 ;A=1 0 0 0 0 0 0 0 0 ,-a; subplot(2,2,3;zplane(B,A;title('(a 零極點(diǎn)分布(¨a=0.9,N=8”Hk,w=freqz(B,A,1024;subplot(2,2,4;plot(w/pi,abs(Hk/max(abs(Hk ;xlabel('omega/pi'ylabel('|H(ejomega|'axis(0,1,0,1.5;title('(b·幅頻特性¨a=0.9,N=8£©' % 79頁(yè)xn=1 1 1

7、 1;Xk16=fft(xn,16;magXk16=abs(Xk16;phaXk16=angle(Xk16;subplot(2,2,1k1=0:length(magXk16-1;stem(k1,magXk16,'.'xlabel('k'ylabel('|X(k|' title('16點(diǎn)幅頻特性 'subplot(2,2,2;stem(k1,phaXk16, '.'title('16點(diǎn)相頻響應(yīng)¦'Xk32=fft(xn,32;magXk32=abs(Xk32;phaXk32=angle(Xk

8、32;subplot(2,2 ,3k2=0:length(magXk32-1;stem(k2,magXk32,'.'xlabel('k'ylabel('|X(k|' title('32 點(diǎn)幅頻特性'subplot(2,2,4;stem(k2,phaXk32, 'r'title('32點(diǎn)相頻響應(yīng)¦'82頁(yè)先定義函數(shù)function y=circonvt(x1,x2,Nif length(x1>Nerror('N must be >the length o f x1'

9、;endif length(x2>Nerror('N must be >the length o f x2'endx1=x1,zeros(1,N-length(x1; x2=x2,zeros(1,N-length(x2; m=0:1:N-1;x2=x2(mod(-m,N+1;H=zeros(N,N;for n=1:1:NH(n,:=cirshftt(x2,n-1,N; endy=x1*H'function y=cirshftt(x,m,Nif length(x>Nerror('N must be >thelength(x'endx

10、=x,zeros(1,N-length(x;n=0:1:N-1;n=mod(n-m,N;y=x(n+1;% 82頁(yè)h=1 2 3 4x=1 1 1 1y1=circonvt(h,x,4y2=circonvt(h,x,8subplot(2,2,1;n1=0:3;n2=0:7;h1=stem(n1,h,'.'line(0 6,0 0axis(0,6,0,6xlabel('n'ylabel('h(n'title('h(n'grid onsubplot(2,2,2;h1=stem(n1,x,'r'line(0 6,0 0a

11、xis(0,6,0,2xlabel('n'ylabel('x(n'title('x(n'grid onsubplot(2,2,3;h1=stem(n1,y1 ,'g'line(0 12,0 0axis(0,10,0,12xlabel('n'ylabel('y1(n'title('4點(diǎn)循環(huán)卷積'grid onsubplot(2,2,4;h1=stem(n2,y2,'.'line(0 12,0 0axis(0,10,0,12xlabel('n'ylabel

12、('y2(n'title('8點(diǎn)循環(huán)卷積'grid on% 89頁(yè)M=26;N=32;n=0:M;xa=0:M/2;xb=ceil(M/2-1:-1:0;xn=xa,xb;Xk=fft(xn,512;X32k=fft(xn,32;x32n=ifft(X32k;X16k=X32k(1:2:N;x16n=ifft(X16k,N/2;k=0:511;wk=2*k/512; %subplot(3,2,1;plot(wk,abs(Xk ;title('(aFTx(n'xlabel('omega/pi'ylabel('|X(ejome

13、ga|'axis(0,1,0,200subplot(3,2,2;stem(n,xn,'.' box ontitle(b三角波序列x(n;xlabel('n'ylabel('x(n'axis(0,32,0,15k=0:N/2-1;subplot(3,2,3;stem(k,abs(X16k ,'.'box ontitle('(c 16點(diǎn)頻域采樣'xlabel('k'ylabel('|X_1_6(k|'axis(0,8, 0,200n1=0:N/2-1;subplot(3,2,4;

14、stem(n1,x16n,'.' ;box on title('(d 16點(diǎn)DFTX_1_6(k'xlabel('n' ylabel('x_1_6(n'axis(0,32,0 ,15k=0:N-1;subplot(3,2,5;stem(k,abs(X32k ,'.'box ontitle('(e 32點(diǎn)頻域采樣'xlabel('k'ylabel('|X_3_2(k|'axis(0,16 ,0,200n1=0:N-1;subplot(3,2,6;stem(n1,x32n

15、,'.' ;box ontitle('(f 32點(diǎn)IDFTX_3_2(k'xlabel('n' ylabel('x_3_2(n'axis(0,32,0 ,15% 93頁(yè)Lx=41,N=5,M=10hn=ones(1,Nhn1=hn,zeros(1,Lx-Nn=0:Lx-1xn=cos(pi*n/10+cos(2*pi*n/5 yn=fftfilt(hn,xn,Msubplot(311stem(hn1xlabel('n'ylabel('h(n的波形'title('系統(tǒng)函數(shù)的波形'sub

16、plot(312stem(xnxlabel('n'ylabel('x(n的樣本值'title('x(n函數(shù)的波形'gtext('x(n函數(shù)的波形'subplot(313stem(ynxlabel('n'ylabel('x(n的卷積值'title(' y(n的波形'gtext('y(n函數(shù)的波形'實(shí)驗(yàn)一%實(shí)驗(yàn)1:系統(tǒng)響應(yīng)及系統(tǒng)穩(wěn)定性close all;clear all%=內(nèi)容1:調(diào)用filter解差分方程,由系統(tǒng)對(duì)u(n的響應(yīng)判斷穩(wěn)定性= A=1,-0.9;B=0.0

17、5,0.05; %系統(tǒng)差分方程系數(shù)向量B和Ax1n=1 1 1 1 1 1 1 1 zeros(1,50; %產(chǎn)生信號(hào)x1(n=R8(nx2n=ones(1,128; %產(chǎn)生信號(hào)x2(n=u(nhn=impz(B,A,58; %求系統(tǒng)單位脈沖響應(yīng)h(nsubplot(2,2,1;y='h(n'stem(hn; %調(diào)用函數(shù)stem繪圖title('(a 系統(tǒng)單位脈沖響應(yīng)h(n'box ony1n=filter(B,A,x1n; %求系統(tǒng)對(duì)x1(n的響應(yīng)y1(nsubplot(2,2,2;y='y1(n'stem(y1n;title('(b

18、系統(tǒng)對(duì)R8(n的響應(yīng)y1(n'box ony2n=filter(B,A,x2n; %求系統(tǒng)對(duì)x2(n的響應(yīng)y2(nsubplot(2,2,4;y='y2(n'stem(y2n;title('(c 系統(tǒng)對(duì)u(n的響應(yīng)y2(n'box on%=內(nèi)容2:調(diào)用conv函數(shù)計(jì)算卷積= x1n=1 1 1 1 1 1 1 1 ; %產(chǎn)生信號(hào)x1(n=R8(nh1n=ones(1,10 zeros(1,10;h2n=1 2.5 2.5 1 zeros(1,10;y21n=conv(h1n,x1n;y22n=conv(h2n,x1n;figure(2subplot(2,

19、2,1;y='h1(n'stem(h1n; %調(diào)用函數(shù)stem繪圖title('(d 系統(tǒng)單位脈沖響應(yīng)h1(n'box onsubplot(2,2,2;y='y21(n'stem(y21n;title('(e h1(n與R8(n的卷積y21(n'box onsubplot(2,2,3;y='h2(n'stem(h2n; %調(diào)用函數(shù)stem繪圖title('(f 系統(tǒng)單位脈沖響應(yīng)h2(n'box onsubplot(2,2,4;y='y22(n'stem(y22n;title('

20、;(g h2(n與R8(n的卷積y22(n'box on%=內(nèi)容3:諧振器分析=un=ones(1,256; %產(chǎn)生信號(hào)u(nn=0:255;xsin=sin(0.014*n+sin(0.4*n; %產(chǎn)生正弦信號(hào)A=1,-1.8237,0.9801;B=1/100.49,0,-1/100.49; %系統(tǒng)差分方程系數(shù)向量B和A y31n=filter(B,A,un; %諧振器對(duì)u(n的響應(yīng)y31(ny32n=filter(B,A,xsin; %諧振器對(duì)u(n的響應(yīng)y31(nfigure(3subplot(2,1,1;y='y31(n'stem(y31n;title(

21、9;(h 諧振器對(duì)u(n的響應(yīng)y31(n'box onsubplot(2,1,2;y='y32(n'stem(y32n;title('(i 諧振器對(duì)正弦信號(hào)的響應(yīng)y32(n'box on實(shí)驗(yàn)二% 時(shí)域采樣理論驗(yàn)證程序exp2a.mfigure(1Tp=64/1000; %觀察時(shí)間Tp=64微秒%產(chǎn)生M長(zhǎng)采樣序列x(n% Fs=1000;T=1/Fs;Fs=1000;T=1/Fs;M=Tp*Fs;n=0:M-1;A=444.128;alph=pi*50*20.5;omega=pi*50*20.5;xnt=A*exp(-alph*n*T.*sin(omega

22、*n*T;Xk=T*fft(xnt,M; %M點(diǎn)FFTxntyn='xa(nT'subplot(3,2,1;stem(xnt; %調(diào)用自編繪圖函數(shù)繪制序列圖box on;title('(a Fs=1000Hz'k=0:M-1;fk=k/Tp;subplot(3,2,2;plot(fk,abs(Xk;title('(aT*FTxa(nT,Fs=1000Hz'xlabel('f(Hz'ylabel('·幅度'axis(0,Fs,0,1.2*max(abs(Xk%=% Fs=300Hz和 Fs=200Hz的程序

23、與Fs=1000Hz完全相同F(xiàn)s=300;T=1/Fs;M=Tp*Fs;n=0:M-1;A=444.128;alph=pi*50*20.5;omega=pi*50*20.5;xnt=A*exp(-alph*n*T.*sin(omega*n*T;Xk=T*fft(xnt,M; %M點(diǎn)FFTxntyn='xa(nT'subplot(3,2,3;stem(xnt; %調(diào)用自編繪圖函數(shù)繪制序列圖box on;title('(a Fs=300Hz'k=0:M-1;fk=k/Tp;subplot(3,2,4;plot(fk,abs(Xk;title('(a T*FT

24、xa(nT,Fs=300Hz'xlabel('f(Hz'ylabel('·幅度'axis(0,Fs,0,1.2*max(abs(XkFs=200;T=1/Fs;M=Tp*Fs;n=0:M-1;A=444.128;alph=pi*50*20.5;omega=pi*50*20.5;xnt=A*exp(-alph*n*T.*sin(omega*n*T;Xk=T*fft(xnt,M; %M點(diǎn)FFTxntyn='xa(nT'subplot(3,2,5;stem(xnt; %調(diào)用自編繪圖函數(shù)繪制序列圖box on;title('(a

25、 Fs=200Hz'k=0:M-1;fk=k/Tp;subplot(3,2,6;plot(fk,abs(Xk;title('(a T*FTxa(nT,Fs=200Hz'xlabel('f(Hz'ylabel('·幅度'axis(0,Fs,0,1.2*max(abs(Xk% 2頻域采樣驗(yàn)證程序figure(2% 頻域采樣驗(yàn)證程序exp2b.mM=27;N=32;n=0:M; %產(chǎn)生M長(zhǎng)三角波序列x(nxa=0:floor(M/2; xb= ceil(M/2-1:-1:0; xn=xa,xb;Xk=fft(xn,1024; %102

26、4點(diǎn)FFTx(n, 用于近似序列x(n的TF X32k=fft(xn,32 ;%32點(diǎn)FFTx(nx32n=ifft(X32k; %32點(diǎn)IFFTX32(k得到x32(nX16k=X32k(1:2:N; %隔點(diǎn)抽取X32k得到X16(Kx16n=ifft(X16k,N/2; %16點(diǎn)IFFTX16(k得到x16(nk=0:1023;wk=2*k/1024; %subplot(3,2,1;plot(wk,abs(Xk;title('(aFTx(n'xlabel('omega/pi'ylabel('|X(ejomega|'axis(0,2,0,200

27、;subplot(3,2,2;stem(n,xn,'.'box ontitle('(b三角波序列x(n'xlabel('n'ylabel('x(n'axis(0,32,0,20k=0:N/2-1;subplot(3,2,3;stem(k,abs(X16k,'.'box ontitle('(c 16點(diǎn)頻域采樣'xlabel('k'ylabel('|X_1_6(k|'axis(0,8,0,200n1=0:N/2-1;subplot(3,2,4;stem(n1,x16n,&

28、#39;.'box ontitle('(d 16點(diǎn)IDFTX_1_6(k'xlabel('n'ylabel('x_1_6(n' axis(0,32,0,20k=0:N-1;subplot(3,2,5;stem(k,abs(X32k,'.'box ontitle('(e 32點(diǎn)頻域采樣'xlabel('k'ylabel('|X_3_2(k|'axis(0,16,0,200n1=0:N-1;subplot(3,2,6;stem(n1,x32n,'.'box ont

29、itle('(f 32點(diǎn)IDFTX_3_2(k'xlabel('n'ylabel('x_3_2(n'axis(0,32,0,20實(shí)驗(yàn)三% 用FFT對(duì)信號(hào)做頻譜分析clear all;close all%實(shí)驗(yàn)內(nèi)容(1=x1n=ones(1,4; %產(chǎn)生序列x1(n=R4(nM=8;xa=1:(M/2; xb=(M/2:-1:1; x2n=xa,xb; %產(chǎn)生長(zhǎng)度為8的三角波序列x2(nx3n=xb,xa;X1k8=fft(x1n,8; %計(jì)算x1n的8點(diǎn)DFTX1k16=fft(x1n,16; %計(jì)算x1n的16點(diǎn)DFTX2k8=fft(x2n,8

30、; %計(jì)算x2n的8點(diǎn)DFTX2k16=fft(x2n,16; %計(jì)算x2n的16點(diǎn)DFTX3k8=fft(x3n,8; %計(jì)算x3n的8點(diǎn)DFTX3k16=fft(x3n,16; %計(jì)算x3n的16點(diǎn)DFT%繪制頻譜特性曲線k1=0:length(X1k8-1subplot(2,2,1;stem(k1,X1k8,'.' 繪制8點(diǎn)的DFT的幅頻特性曲線title('(1a 8µãDFTx_1(n'xlabel('¦Ø/¦Ð'ylabel('·ù¶&#

31、200;'axis(0,8,0,1.2*max(abs(X1k8;k2=0:length(X1k16-1subplot(2,2,3;stem(k2,X1k16,'.' 繪制16點(diǎn)的DFT的幅頻特性曲線title('(1b16µãDFTx_1(n'xlabel('¦Ø/¦Ð'ylabel('·ù¶È'axis(0,16,0,1.2*max(abs(X1k16figure(2subplot(2,2,1;stem(k1,X2k8,

32、'.' 繪制8點(diǎn)的DFT的幅頻特性曲線title('(2a 8點(diǎn)DFTx_2(n'xlabel('¦Ø/¦Ð'ylabel('幅度'axis(0,8,0,1.2*max(abs(X2k8subplot(2,2,2;stem(k2,X2k16,'.' 繪制16點(diǎn)的DFT的幅頻特性曲線title('(2b16點(diǎn)DFTx_2(n'xlabel('¦Ø/¦Ð'ylabel('幅度'axis(0,1

33、6,0,1.2*max(abs(X2k16subplot(2,2,3;stem(k1,X3k8,'.' 繪制8點(diǎn)的DFT的幅頻特性曲線title('(3a 8點(diǎn)DFTx_3(n'xlabel('¦Ø/¦Ð'ylabel('幅度'axis(0,8,0,1.2*max(abs(X3k8subplot(2,2,4;stem(k2,X3k16,'.' 繪制16點(diǎn)的DFT的幅頻特性曲線title('(3b16點(diǎn)DFTx_3(n'xlabel('¦

34、16;/¦Ð'ylabel('幅度'axis(0,16,0,1.2*max(abs(X3k16%實(shí)驗(yàn)內(nèi)容2 周期序列的頻譜分析=N1=8;n=0:N1-1; %FFT的變換區(qū)間N=8x4n=cos(pi*n/4;x5n=cos(pi*n/4+cos(pi*n/8;X4k8=fft(x4n,8; %計(jì)算x4n的8點(diǎn)DFTX5k8=fft(x5n,8; 計(jì)算x5n的8點(diǎn)DFTN2=16;n=0:N2-1; %FFT的變換區(qū)間N=16x4n=cos(pi*n/4;x5n=cos(pi*n/4+cos(pi*n/8;X4k16=fft(x4n,16; %計(jì)算

35、x4n的16點(diǎn)DFTX5k16=fft(x5n,16; %計(jì)算x5n的16點(diǎn)DFTfigure(3k3=0:length(X4k8-1;subplot(2,2,1;stem(k3,X4k8,'.' %繪制8 點(diǎn)的DFT幅頻特性title('(4a 8µãDFTx_4(n'xlabel('¦Ø/¦Ð'ylabel('幅度'axis(0,8,0,1.2*max(abs(X4k8k4=0:length(X4k16-1subplot(2,2,3;stem(k4,X4k16,

36、9;.' %繪制16點(diǎn)的DFT幅頻特性title('(4b16µãDFTx_4(n'xlabel('¦Ø/¦Ð'ylabel('幅度'axis(0,16,0,1.2*max(abs(X4k16subplot(2,2,2;stem(k3,X5k8,'.' %繪制8 點(diǎn)的DFT幅頻特性title('(5a 8µãDFTx_5(n'xlabel('¦Ø/¦Ð'ylabel(

37、9;·幅度'axis(0,8,0,1.2*max(abs(X5k8subplot(2,2,4;stem(k4,X5k16,'.' %繪制16點(diǎn)的DFT幅頻特性title('(5b16µãDFTx_5(n'xlabel('¦Ø/¦Ð'ylabel('·幅度;axis(0,16,0,1.2*max(abs(X5k16%實(shí)驗(yàn)內(nèi)容(3 模擬周期信號(hào)頻譜分析=figure(4Fs=64;T=1/Fs;N=16;n=0:N-1; %FFT變換區(qū)間N=16x6nT=

38、cos(8*pi*n*T+cos(16*pi*n*T+cos(20*pi*n*T; %對(duì)X6(t16 點(diǎn)的采樣X(jué)6k16=fft(x6nT; %計(jì)算x6n的16點(diǎn)DFTX6k16=fftshift(X6k16; %將零頻率移到頻譜中心Tp=N*T;F=1/Tp; %頻率分辨率Fk=-N/2:N/2-1;fk=k*F; %產(chǎn)生16點(diǎn)DFT對(duì)應(yīng)的采樣頻率subplot(3,1,1;stem(fk,abs(X6k16,'.'box on%繪制8點(diǎn)的DFT幅頻特性title('(6a 16µã|DFTx_6(nT|'xlabel('f(Hz&

39、#39;ylabel('·幅度' axis(-N*F/2-1,N*F/2-1,0,1.2*max(abs(X6k16N=32;n=0:N-1; %FFT變換區(qū)間N=32x6nT=cos(8*pi*n*T+cos(16*pi*n*T+cos(20*pi*n*T; %對(duì)X6(t16 點(diǎn)的采樣X(jué)6k32=fft(x6nT; %計(jì)算x6n的16點(diǎn)DFTX6k32=fftshift(X6k32; %將零頻率移到頻譜中心Tp=N*T;F=1/Tp; %頻率分辨率Fk=-N/2:N/2-1;fk=k*F; %產(chǎn)生16點(diǎn)DFT對(duì)應(yīng)的采樣頻率subplot(3,1,2;stem(fk,

40、abs(X6k32,'.'box on%繪制8點(diǎn)的DFT幅頻特title('(6b 32點(diǎn)|DFTx_6(nT|'xlabel('f(Hz'ylabel('幅度' axis(-N*F/2-1,N*F/2-1,0,1.2*max(abs(X6k32N=64;n=0:N-1; %FFT變換區(qū)間N=32x6nT=cos(8*pi*n*T+cos(16*pi*n*T+cos(20*pi*n*T; %對(duì)X6(t16 點(diǎn)的采樣X(jué)6k64=fft(x6nT; %計(jì)算x6n的16點(diǎn)DFTX6k64=fftshift(X6k64; %將零頻率移到頻

41、譜中心Tp=N*T;F=1/Tp; %頻率分辨率Fk=-N/2:N/2-1;fk=k*F; %產(chǎn)生16點(diǎn)DFT對(duì)應(yīng)的采樣頻率subplot(3,1,3;stem(fk,abs(X6k64,'.' box on%繪制8點(diǎn)的DFT幅頻特title('(6a 64點(diǎn)|DFTx_6(nT|'xlabel('f(Hz'ylabel('幅度' axis(-N*F/2-1,N*F/2-1,0,1.2*max(abs(X6k64gtext(模擬周期信號(hào)頻譜分析IIR實(shí)驗(yàn)四function myplot(B,A%計(jì)算時(shí)域離散系統(tǒng)損耗函數(shù)并繪圖H,W

42、=freqz(B,A,1000;m=abs(H;plot(W/pi,20*log10(m/max(m;grid on;xlabel('omega/pi'ylabel('幅度(db'axis(0,1,-80,5;title('損耗函數(shù)曲線'function tplot(xn,T,yn %時(shí)域序列連續(xù)曲線繪圖%xn:信號(hào)數(shù)據(jù)序列;yn:繪圖信號(hào)的縱坐標(biāo)名稱n=0:length(xn-1;t=n*T; plot(t,xn;xlabel('t/s'ylabel(yn;axis(0,t(end,min(xn,1.2*max(xn;funct

43、ion st=mstg %產(chǎn)生信號(hào)序列向量st,并顯示st的時(shí)域波形和頻譜%st=mstg 返回三路調(diào)幅信號(hào)相加形成的混合信號(hào),長(zhǎng)度N=1600N=1600 %N為信號(hào)st的長(zhǎng)度。Fs=10000;T=1/Fs;Tp=N*T; %采樣頻率Fs=10kHz,Tp為采樣時(shí)間t=0:T:(N-1*T;k=0:N-1;f=k/Tp;fc1=Fs/10; %第1路調(diào)幅信號(hào)的載波頻率fc1=1000Hz,fm1=fc1/10; %第1路調(diào)幅信號(hào)的調(diào)制信號(hào)頻率fm1=100Hzfc2=Fs/20; %第2路調(diào)幅信號(hào)的載波頻率fc2=500Hzfm2=fc2/10; %第2路調(diào)幅信號(hào)的調(diào)制信號(hào)頻率fm2=50

44、Hzfc3=Fs/40; %第3路調(diào)幅信號(hào)的載波頻率fc3=250Hz,fm3=fc3/10; %第3路調(diào)幅信號(hào)的調(diào)制信號(hào)頻率fm3=25Hzxt1=cos(2*pi*fm1*t.*cos(2*pi*fc1*t; %產(chǎn)生第1路調(diào)幅信號(hào)xt2=cos(2*pi*fm2*t.*cos(2*pi*fc2*t; %產(chǎn)生第2路調(diào)幅信號(hào)xt3=cos(2*pi*fm3*t.*cos(2*pi*fc3*t; %產(chǎn)生第3路調(diào)幅信號(hào)st=xt1+xt2+xt3; %三路調(diào)幅信號(hào)相加fxt=fft(st,N; %計(jì)算信號(hào)st的頻譜%=以下為繪圖部分,繪制st的時(shí)域波形和幅頻特性曲線= subplot(2,1,1p

45、lot(t,st;grid;xlabel('t/s'ylabel('s(t'axis(0,Tp/8,min(st,max(st;title('(a s(t的波形'subplot(2,1,2stem(f,abs(fxt/max(abs(fxt,'.'grid;title('(b s(t的頻譜'axis(0,Fs/5,0,1.2;xlabel('f/Hz'ylabel('幅度'% IIR數(shù)字濾波器設(shè)計(jì)及軟件實(shí)現(xiàn)clear all;close allFs=10000;T=1/Fs; %采樣

46、頻率%調(diào)用信號(hào)產(chǎn)生函數(shù)mstg產(chǎn)生由三路抑制載波調(diào)幅信號(hào)相加構(gòu)成的復(fù)合信號(hào)stst=mstg;%低通濾波器設(shè)計(jì)與實(shí)現(xiàn)=fp=280;fs=450;wp=2*fp/Fs;ws=2*fs/Fs;rp=0.1;rs=60; %DF指標(biāo)(低通濾波器的通、阻帶邊界頻N,wp=ellipord(wp,ws,rp,rs; %調(diào)用ellipord計(jì)算橢圓DF階數(shù)N和通帶截止頻率wpB,A=ellip(N,rp,rs,wp; %調(diào)用ellip計(jì)算橢圓帶通DF系統(tǒng)函數(shù)系數(shù)向量B和Ay1t=filter(B,A,st; %濾波器軟件實(shí)現(xiàn)% 低通濾波器設(shè)計(jì)與實(shí)現(xiàn)繪圖部分figure(2;subplot(2,1,1;m

47、yplot(B,A; %調(diào)用繪圖函數(shù)myplot繪制損耗函數(shù)曲線yt='y_1(t'subplot(2,1,2;tplot(y1t,T,yt; %調(diào)用繪圖函數(shù)tplot繪制濾波器輸出波形%帶通濾波器設(shè)計(jì)與實(shí)現(xiàn)= fpl=440;fpu=560;fsl=275;fsu=900;wp=2*fpl/Fs,2*fpu/Fs;ws=2*fsl/Fs,2*fsu/Fs;rp=0.1;rs=60;N,wp=ellipord(wp,ws,rp,rs; %調(diào)用ellipord計(jì)算橢圓DF階數(shù)N和通帶截止頻率wpB,A=ellip(N,rp,rs,wp; %調(diào)用ellip計(jì)算橢圓帶通DF系統(tǒng)函數(shù)系

48、數(shù)向量B和Ay2t=filter(B,A,st; %濾波器軟件實(shí)現(xiàn)figure(3;subplot(2,1,1;myplot(B,A;subplot(2,1,2;yt='y_2(t'tplot(y2t,T,yt;%高通濾波器設(shè)計(jì)與實(shí)現(xiàn)=fp=890;fs=600;wp=2*fp/Fs;ws=2*fs/Fs;rp=0.1;rs=60; %DF指標(biāo)(低通濾波器的通、阻帶邊界頻 N,wp=ellipord(wp,ws,rp,rs; %調(diào)用ellipord計(jì)算橢圓DF階數(shù)N和通帶截止頻率wp B,A=ellip(N,rp,rs,wp,'high' %調(diào)用ellip計(jì)算橢

49、圓帶通DF系統(tǒng)函數(shù)系數(shù)向量B和Ay3t=filter(B,A,st; %濾波器軟件實(shí)現(xiàn)figure(4;subplot(2,1,1;myplot(B,A;subplot(2,1,2;yt='y_3(t'tplot(y3t,T,yt;FIR實(shí)驗(yàn)五信號(hào)產(chǎn)生函數(shù)xtg程序清單function xt=xtg(N%實(shí)驗(yàn)五信號(hào)x(t產(chǎn)生,并顯示信號(hào)的幅頻特性曲線%xt=xtg(N 產(chǎn)生一個(gè)長(zhǎng)度為N,有加性高頻噪聲的單頻調(diào)幅信號(hào)xt,采樣頻率Fs=1000Hz %載波頻率fc=Fs/10=100Hz,調(diào)制正弦波頻率f0=fc/10=10Hz.N=1000;Fs=1000;T=1/Fs;Tp=

50、N*T;t=0:T:(N-1*T;fc=Fs/10;f0=fc/10; %載波頻率fc=Fs/10,單頻調(diào)制信號(hào)頻率為f0=Fc/10;mt=cos(2*pi*f0*t; %產(chǎn)生單頻正弦波調(diào)制信號(hào)mt,頻率為f0ct=cos(2*pi*fc*t; %產(chǎn)生載波正弦波信號(hào)ct,頻率為fcxt=mt.*ct; %相乘產(chǎn)生單頻調(diào)制信號(hào)xtnt=2*rand(1,N-1; %產(chǎn)生隨機(jī)噪聲nt%=設(shè)計(jì)高通濾波器hn,用于濾除噪聲nt中的低頻成分,生成高通噪聲= fp=150; fs=200;Rp=0.1;As=70; % 濾波器指標(biāo)fb=fp,fs;m=0,1; % 計(jì)算remezord函數(shù)所需參數(shù)f,m,devdev=10(-As/20,(10(Rp/20-1/(10(Rp/20+1;n,fo,mo,W=remezord(fb,m,dev,Fs; % 確定remez函數(shù)所需參數(shù)hn=remez