fft.m

来自「现代谱估计实验」· M 代码 · 共 27 行

x=load('BBB.TXT');
fs=200;
n=length(x);
r=fft(x)/n;
r=fftshift(r);
f=linspace(-fs,fs,n);
subplot(311);
plot(x);
grid on;
subplot(312);
plot(f,abs(r));
set(gca,'XTick',-fs:50:fs');
axis tight;
grid on;
s=zeros(1,fs);
for i=1:fs
    s(i)=1/n*(abs(r(i))^2);
end
subplot(313);
plot(s);
axis([0 200 0 0.01]);