lsj31.m

西交大刘树棠写的《数字信号处理》那本书的所有源代码

f0=50;T=1/f0;
N=16;
t=T:T:N*T;

x=sin(2*pi*t);
subplot(3,2,1);
stem(t,x);
X=dft(x,N);
magX=abs(X);
f=1./t;
subplot(3,2,2);
stem(f,magX);grid;
title('fs=50Hz');

f1=100;T1=1/f1;
t1=T1:T1:N*T1;
x1=sin(2*pi*t1);
X1=dft(x1,N);
magX1=abs(X1);
subplot(3,2,3);
stem(f,magX1);grid;
title('fs=100Hz');

f2=150;T2=1/f2;
t2=T2:T2:N*T2;
x2=sin(2*pi*t2);
X2=dft(x2,N);
magX2=abs(X2);
subplot(3,2,4);
stem(f,magX2);grid;
title('fs=150Hz');

f3=200;T3=1/f3;
t3=T3:T3:N*T3;
x3=sin(2*pi*t3);
X3=dft(x3,N);
magX3=abs(X3);
subplot(3,2,5);
stem(f,magX3);grid;
title('fs=200Hz');

xx=[x,zeros(1,16)];
XX=dft(xx,32);
magXX=abs(XX);
tx=T:T:2*N*T;
fx=1./tx;
figure;
stem(fx,magXX);grid;