Linked Questions

0 votes
1 answer
7k 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 <...
ravi3's user avatar
  • 1
0 votes
1 answer
393 views

Using Fourier to get the numerical FT of a Gaussian [duplicate]

I've been trying to find the FT of a more complicated function, but it seems my method is wrong. To check, I tried to calculate the FT of a Gaussian numerically. This is what I did: ...
123infinity's user avatar
0 votes
0 answers
128 views

Help with Frequency Identification with Fourier? [duplicate]

Note: This question has 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 should be ...
user3769181's user avatar
0 votes
0 answers
68 views

Frequencies for Fourier coefficients [duplicate]

I have been given the task of calculating the frequencies to which the fourier coefficients correspond. So my input is a discrete signal [1,4,0,1], which gives me <...
greedsin's user avatar
  • 101
0 votes
0 answers
35 views

Getting frequency domain data from time domain using Fourier transformation [duplicate]

I have a dataset following cosine function [e.g. cos(200t)] in time domain. In frequency domain two sharp lines should appear at -200 and +200. I have to do Fourier transform (or Fast Fourier ...
P Pyne's user avatar
  • 453
23 votes
6 answers
31k views

How do you find the frequency and amplitude from Fourier?

Edit This is a popular question with several answers. This edit organises the answers and gives links. Fourier just gives y values (ordinates) if you wish to read off frequencies and amplitudes you ...
Hugh's user avatar
  • 16.5k
23 votes
3 answers
5k views

How to make Fourier behave like FourierTransform?

I'm not very experienced with Fourier Transforms, so there may be something inherently wrong with attempting to do this, but how can I make the discrete Fourier behave like the continuous ...
EmpireJones's user avatar
22 votes
4 answers
7k views

How to calculate the Fourier Transform of a Gaussian pulse with a nonlinear chirp: Cos[ t + Exp[t^2] ]?

I have an optical pulse in time domain: Exp[-t^2] Cos[50 t - Exp[-2 t^2] 8 π]. The figure of this formula is I hope to calculate the Fourier Transform of this ...
user14634's user avatar
  • 771
16 votes
2 answers
15k views

Does Mathematica implement the fast Fourier transform?

Is there a fast Fourier transform in Mathematica? Although looking in the help I could not find one. I am looking to implement the equivalent of fft in MATLAB.
500's user avatar
  • 5,579
7 votes
3 answers
979 views

extracting phase from sinusoidal data

I am dealing with data which are essentially are sinusoidal with various degrees of noise. I have an interest in extracting the phase of the data and rather than simply fitting a sine wave, I would ...
alex's user avatar
  • 1,438
5 votes
2 answers
8k views

Using Mathematica to take Fourier transform of data

i'm trying to use Mathematica to take a discrete Fourier transform of 68 data points (0 to 67) to perform further analysis. My data points, when plotted, look like this: Pretty straightforward. Now, ...
amantonas's user avatar
10 votes
2 answers
802 views

Frequency of ticks in mechanical watches

I'm looking to find the frequency of a relatively large dataset (or a relatively short audio file) of a repeating sound, like so: Here are the original files, for those willing to play. :) eta2412 ...
DrMrstheMonarch's user avatar
8 votes
4 answers
737 views

Challenge: Computing the Fourier Series of a List Plot!

I have a bunch of data points (copied from Mathematica below), which I have 'ListPlotted' I would now like to compute the Fourier series of this function (after doing a Fourier transform I assume? Or ...
rdx's user avatar
  • 103
5 votes
1 answer
3k views

Differences between FFT and analytical Fourier Transform

In MATLAB, if I perform an FFT on a simple Gaussian spot with a phase grating: ...
user12800's user avatar
10 votes
1 answer
1k views

finding Frequency of Sinewave data using Fourier

CONTEXT I read 5 different related posts but I do not understand how to interpret mathematica's output for my situation. ...
Conor's user avatar
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