example3_11.m

西交大刘树棠写的《数字信号处理》那本书的所有源代码

x=[1,1,1,1,zeros(1,4)];
n=0:7;
N=8;
X=dft(x,N);
magX=abs(X);
phaX=angle(X)*180/pi;
subplot(2,2,1);stem(n,magX);axis([0,8,0,5]);
xlabel('k');ylabel('|x(k)|');
title('amplitude of DFT(N=8)');
subplot(2,2,2);stem(n,phaX);axis([0,8,-200,200]);
xlabel('k');ylabel('degree');
title('phase of DFT(N=8)');

x1=[1,1,1,1,zeros(1,12)];
n1=0:15;
N1=16;
X1=dft(x1,N1);
magX1=abs(X1);
phaX1=angle(X1)*180/pi;
subplot(2,2,3);stem(n1,magX1);axis([0,16,0,5]);
xlabel('k');ylabel('|x(k)|');
title('amplitude of DFT(N=16)');
subplot(2,2,4);stem(n1,phaX1);axis([0,16,-200,200]);
xlabel('k');ylabel('degree');
title('phase of DFT(N=16)');