数字信号处理99511

数字信号处理实验报告班级学号姓名实验一：频谱分析与采样定理程序T=0.0001;F=1/T;L=0.02;N=L/T;t=0:T:L;a=16;f1=0:F/N:F;f2=-F/2:F/N:F/2; %%%%%%%%%%%%%%%%%%x1=cos(100*pi*16*t);y1=T*abs(fft(x1));y11=fftshift(y1);figure(1),subplot(3,1,1),plot(t,x1),title('正弦信号');subplot(3,1,2),plot(f1,y1),title('正弦信号频谱');subplot(3,1,3),plot(f2,y1),title('正弦信号频谱');%%%%%%%%%%%%%%%%%%%%x2=exp(-16*t);y2=T*abs(fft(x2));y21=fftshift(y2);figure(2),subplot(3,1,1),plot(t,x2),title('指数信号');subplot(3,1,2),plot(f1,y2),title('指数信号频谱');subplot(3,1,3),plot(f2,y21),title('指数信号频谱');%%%%%%%%%%%%%%%%%%%%%%x3=x1.*x2;y3=T*abs(fft(x3));y31=fftshift(y3);figure(3),subplot(3,1,1),stem(t,x3),title('两信号相乘');subplot(3,1,2),stem(f1,y3),title('两信号相乘频谱');subplot(3,1,3),stem(f2,y31),title('两信号相乘频谱');结果实验二 卷积定理程序x=[30213];%原始序列y=[30213];%直接计算圆周卷积或线性卷积z=conv(x,y);figure(1),subplot(311),stem(x);axis([1904]);subplot(312),stem(y);axis([1904]);subplot(313),stem(z);axis([19030]);%利用FFT计算N=10;%N=8时x1=[xzeros(1,N-length(x))];y1=[yzeros(1,N-length(y))];X1=fft(x1);Y1=fft(y1);Z1=X1.*Y1;z1=ifft(Z1);figure(2),subplot(321),stem(x1);subplot(322),stem(real(X1));subplot(323),stem(y1);subplot(324),stem(real(X1));subplot(325),stem(z1);subplot(326),stem(real(Z1));N=5;%N=5时x2=[xzeros(1,N-length(x))];y2=[yzeros(1,N-length(y))];X2=fft(x2);Y2=fft(y2);Z2=X2.*Y2;z2=ifft(Z2);figure(3),subplot(321),stem(x2);subplot(322),stem(real(X2));subplot(323),stem(y2);subplot(324),stem(real(X2));subplot(325),stem(z2);subplot(326),stem(real(Z2)); 结果实验3程序wp=0.2*pi;ws=0.3*pi;Rp=1;Rs=15;Ts=0.02*pi;Fs=1/Ts;wp1=2/Ts*tan(wp/2);ws1=2/Ts*tan(ws/2);[N,Wn]=buttord(wp1,ws1,Rp,Rs,'s');[Z,P,K]=buttap(N);[Bap,Aap]=zp2tf(Z,P,K);[b,a]=lp2lp(Bap,Aap,Wn);[bz,az]=bilinear(b,a,Fs);[H,W]=freqz(bz,az,50);L=length(W)/2+1;figure(1),plot(W(1:L)/pi,abs(H(1:L))),grid,xlabel('角频率(\pi)'),ylabel('频率响应幅度');x=[-4,-2,0,-4,-6,-4,-2,-4,-6,-6,-4,-4,-6,-6,-2,6,12,8,0,-16,-38,...-60,-84,-90,-66,-32,-4,-2,-4,8,12,12,10,6,6,6,4,0,0,0,0,0,-2,...-4,0,0,0,-2,-2,0,0,-2,-2,-2,-2,0];y=filter(bz,az,x);figure(2),subplot(2,1,1),plot(x),title('原始信号');subplot(2,1,2),plot(y),title('滤波后信号');结果实验4程序wp1=3000*pi;ws1=6000*pi;wsam1=30000*pi;fsam1=wsam1/(2*pi);passrad=(wp1+ws1)/2/fsam1;A=3.3;wdelta=(ws1-wp1)/fsam1;N=ceil(2*pi/wdelta*A);w1=hamming(N+1);L=N/2+1;n=1:1:N+1;hd=sin(passrad*(n-L))./(pi*(n-L));if