数字信号处理实验.doc

function y=circonvt(x1,x2,N)if length(x1)N error(N =x1 )endif length(x2)N error(N =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:N H(n,:)=cirshift(x2,n-1,N);end y=x1*H;function y=cirshift(x,m,N)if length(x)N error(N =x )endx=x zeros(1,N-length(x);n=0:1:N-1;n=mod(n-m,N);y=x(n+1);clc;clear alln=0:1:11;m=0:1:5;g1=1 2 3 4 5;g2=2 2 0 1 1;y1n=conv(g1,g2);ycn=circonvt(g1,g2,5);ny1=0:1:length(y1n)-1;ny2=0:1:length(ycn)-1;subplot(2,1,1);stem(ny1,y1n);subplot(2,1,2);stem(ny2,ycn);function y=circonvt(x1,x2,N)if length(x1)N error(N =x1 )endif length(x2)N error(N =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:N H(n,:)=cirshift(x2,n-1,N);end y=x1*H;function y=cirshift(x,m,N)if length(x)N error(N =x )endx=x zeros(1,N-length(x);n=0:1:N-1;n=mod(n-m,N);y=x(n+1);clc;clear alln=1:2:17;m=0:1:5;x1=1 3 5 7 9 11 13 15 17;x2=1 -2 3 -2 1;y1n=conv(x1,x2);ycn=circonvt(x1,x2,9);ny1=0:1:length(y1n)-1;ny2=0:1:length(ycn)-1;subplot(2,1,1);stem(ny1,y1n);subplot(2,1,2);stem(ny2,ycn);function Y=overlapsav(x,h,N)Lx=length(x);M=length(h);M1=M-1;L=N-M1; h=h,zeros(1,N-M); x=zeros(1,M1),x,zeros(1,N-1);a=floor(Lx+M1-1)/(L)+1;Y=zeros(1,N);for k=0:a-1 xk=x(k*L+1:k*L+N); b=fft(xk,N); C=fft(h,N); Z=b.*C; Y(k+1,:)=ifft(Z,N);endY=Y(:,M:N);Y=(Y(:)clc;clear allx=1 2 3 4 5 6 7 8 9 10;h=1 0 -1;N=6;Y=overlapsav(x,h,N);Y = Columns 1 through 8 1.0000 2.0000 2.0000 2.0000 2.0000 2.0000 2.0000 2.0000 Columns 9 through 122.0000 2.0000 -9.0000 -10.0000 Y=fftfilt(x,h,N)Y = 1.0000 2.0000 2.0000clc;clear allx1=1 3 5 7 9 11 13 15 17;x2=1 -2 3 -2 1;y=conv(x1,x2);stem (y);clc;clear allx1=1 3 5 7 9 11 13 15 17;x2=1 -2 3 -2 1;N=length(x1) + length(x2)-1;n=0:N-1;x1=x1,zeros(1,N-length(x1);x2=x2,zeros(1,N-length(x2);X1=fft(x1);X2=fft(x2);Y=X1.*X2;y=ifft(Y);subplot(221),stem(n,x1,.);xlabel(n);ylabel(x1(n);title( x1(n);grid;subplot(222),stem(n,x2,.);xlabel(n);ylabel(x2(n);title( x2(n);grid;subplot(223),stem(n,y,.);xlabel(n);ylabel(y(n);title( y(n);grid;clc;clear allx1=1 3 5 7 9 11 13 15 17;x2=1 -2 3 -2 1;N=length(x1) + length(x2)-1;n=0:N-1;x1=x1,zeros(1,N-length(x1);x2=x2,zeros(1,N-length(x2);y0=conv(x1,x2);Y=x1.*x2;y1=ifft(Y);subplot(121),stem(y0,.);subplot(122),stem(n,y1,.);clc;clear allx1=1 3 5 7 9 11 13 15 17;x2=1 -2 3 -2 1;N=length(x1) + length(x2)-1;n=0:N-1;x1=x1,zeros(1