Fourier Transform e^(-t)
显示 更早的评论
Hi. Why in MATLAB, why do we have to add a Heaviside function when doing Fourier transforms? For example when doing a Fourier transform of something simple, e.g. e^(-t), I get an error.
.
%%Error code
syms x w X
f = exp(-x)
X=fourier(f, x, w)
ezplot(X)
.
To fix this I need to write f = exp(-x)*heaviside(x);
Why is this?
回答（3 个）
Torsten
2015-4-10
0 个投票
Because your f is not integrable over IR, but only over IR+.
Or what is integral_{t=-oo}^{t=0} exp(-t) dt ?
Best wishes
Torsten.
3 个评论
himesh
2015-4-10
Torsten
2015-4-10
I mean that
integral_{t=-oo}^{t=00} exp(-t) dt
does not exist, but only
integral_{t=0}^{t=oo} exp(-t) dt.
For the Fourier transform to exist, it would be necessary that
integral_{t=-oo}^{t=00} exp(-t) dt < oo
which is not the case.
Best wishes
Torsten.
himesh
2015-4-11
sarath sai krishna babu gunupudi
2019-9-22
0 个投票
Display the expression after computing Fourier Transform of u(t).
Save u(t) function in variable x and Fourier transform in variable xf.
hategekimana shadrack
2021-12-14
0 个投票
Use matlab to calculate the Fourier series of the following periodic signals.
a. Draw the Amplitude spectrum of signal.
类别
在 帮助中心 和 File Exchange 中查找有关 Discrete Fourier and Cosine Transforms 的更多信息
2021-12-14
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
