Linked Questions
44 questions linked to/from What do the X and Y axis stand for in the Fourier transform domain?
2
votes
1answer
109 views
Using ''Module' and 'Table' to Plot 'Fourier'
I'm trying to make a function that outputs a plot given a particular parameter, whilst using the Mathematica functions Module, Fourier, and Table. This is what I've come up with thus far.
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2
votes
0answers
100 views
Why does Mathematica Fourier transform of finite sequence of numbers require parameters? [closed]
I apologize if this is a basic question, but here goes: The Discrete Fourier transform of a sequence of N complex numbers is uniquely defined by eq.1 in this wiki page,
https://en.wikipedia.org/wiki/...
2
votes
0answers
81 views
Determining Periodicity with Fourier?
Note: This question has previously been marked as a duplicate of What do the X and Y axis stand for in the Fourier transform domain?. While the answer will likely have an overlap, so the question ...
1
vote
3answers
403 views
DFT: Fourier Plot Not Giving Expected Result
I'm trying use Mathematica to compute the Discrete Fourier Transform (DFT) of a table of data points and then plot the result. As a test run, I took values from the function $x=f(t)=\sin(2\pi t) $ for ...
1
vote
1answer
514 views
DFT: why are frequencies mirrored around the frequency axis?
I want to apply Mathematica's DFT procedure, Fourier[], to a Gaussian. Why a Gaussian? Because I know the analytical result.
So I define
...
1
vote
1answer
420 views
Get frequency axis in Fourier transform (and save them)
I am trying to get the Fourier transform of a light-curve (with an even number of points, 300, and equally spaced in time, 6.9 seconds) and my problem is to get the frequency on the x-axis.
I can ...
1
vote
2answers
384 views
Parseval identity in one side Fourier Transform
Is there any posibility to apply Parseval identity(energy in time domain is equal to freq. domain) on One/Single-side Fourier transform?
In other word for "standard" FT the test Mathematica can be
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1
vote
2answers
226 views
DataRange in plotting Fourier
I'm trying to estimate a frequency spectrum of a given discrete function. I have a file which is filled of values of Sine-function $sin(t)$, where $t$ runs from $0.0$ to $100.0$ and a discrete step is ...
1
vote
1answer
79 views
Fast method for numerical integral (Fouriertransform?)
I want to numerically compute following integral (as fast as possible):
\begin{equation}
f(x) = \left| \int e^{ \mathrm{i} p x / 2} f(p) \ \mathrm{d}p\right|^2 ,
\end{equation}
where $f(p)$ is given ...
1
vote
0answers
38 views
Taking Fourier transform with WolframAlpha gives unexpected result [duplicate]
I have noticed that WolframAlpha's definition of the Fourier Transform is different than the one in my book of formulas. In my book the Fourier transform of $f(t)$ is defined as:
$$\int_{-\infty}^{\...
1
vote
1answer
104 views
Finding frequency of oscillation of an particle by Fourier analysis of the trajectory [duplicate]
I am trying to find the resonant frequency of a particle by Fourier analysis of the trajectory.
Here is the data file.
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1
vote
0answers
96 views
Taking numerical Laplace transform of a tabulated data with Mathematica?
I am relatively new to the use of Mathematica in the context of numerical evaluations, therefore I would greatly appreciate a detailed answer and would like to express my gratitude towards any help in ...
1
vote
0answers
216 views
Perform a Fourier Transform on a wavelength scan
I have a plot of the power transmitted through a device as a function of wavelength, from 1500 to 1600nm. There is some Fabry-Perot noise, plus I suspect some other regularities. I would like to ...
0
votes
1answer
187 views
Finding frequency from Fourier transform [closed]
I tried to find frequency using Fourier Transform, but notice that my code have some mistakes which I can't find.
So, my code is below:
...
0
votes
1answer
5k views
Discrete Fourier Transform: help on how to convert x axis in to the frequency when I have a set of data samples [duplicate]
I have a huge data set (400000 sample) and when I plot them
ListLinePlot[Au4, PlotRange -> {All, All}]
I used the following code to Fourier transform it
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