Hi all. I need to plot a Fast Fourier Transform(FFT) of a sinc function

200 次查看(过去 30 天)
Venu Kumar Yadav Hosur
Venu Kumar Yadav Hosur2015-4-18
评论: Image Analyst ,2015-4-18
Hi everyone. I need help on Fast Fourier Transform. By using FFT plot a Sinc function & find the normalization & then also plot the inverse F.F.T of Sinc function and find out the normalization.
Thank you.
  2 个评论
Image Analyst
Image Analyst 2015-4-18
I would ask your instructor for clarification on what "find the normalization" means. It's not standard terminology, or at least I'm not familiar with it. Maybe he means "normalize the curve before you plot it" or something like that. If so, does he want the y height normalized to 1, or the area under the curve?

请先登录,再进行评论。

回答(1 个)

Youssef  Khmou
Youssef Khmou 2015-4-18
Let us consider non causal function, we can use built in function as follows :
Fs=42;Ts=1/Fs;
t=-1:Ts:40*Ts-Ts;
f=5;
y=sinc(pi*t*f);
figure;
plot(t,y);
xlabel('x');
ylabel(' magnitude');
N=512;
fy=(fft(y,N));
figure;
fr=(0:N-1)*Fs/N;
%fy=fy(1:floor(end/2));
%fr=fr(1:floor(end/2));
plot(fr,fftshift(abs(fy)));
xlabel(' frequency x^{-1}');
ylabel(' magnitude');
The width of range is approximately pi*f=15.70.
the second part requires ifft function.

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by