# Questions tagged [fast-fourier-transform]

Use this tag for questions related to the fast Fourier transform, an algorithm that samples a signal over a period of time (or space) and divides it into its frequency components.

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### Siegman Discrete Fourier Transform notation misunderstanding

I was reading A.E. Siegman's Fiber Fourier Optics paper and came across the following equation which was described as the DFT:enter image description here and I don't understand why it's that equation ...
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### FFT in Python without numpy yields other result than with numpy

I tried to find an implementation of the FFT algorithm in Python without the use of the numpy library. I found one and it seemed to work, but when I tested it on a more realistic sample it failed and ...
1answer
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### How does scaling in frequency domain affect real space?

I have a 3 dimensional array of real data corresponding to measurements in physical 3D space, and its corresponding data in spectral space. I want to scale certain specific frequencies in the ...
0answers
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### Fast Fourier transform of the Gaussian function

As I know, the Fourier transform of the Gaussian function is also Gaussian. The simple verification for that is shown below. http://mathworld.wolfram.com/FourierTransformGaussian.html But fast ...
1answer
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### Can FFT be used to cluster sound waves based on their similarity?

I am new to this so apologies if the question appears trivial. Say we have n sound files and we want to cluster them to identify which ones are more similar. I ...
0answers
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### circulant matrix inversion using fast fourier transform

I am Huda. May I know, if I have a circulant matrix, can I calculate its inversion using fast fourier transform? If yes, I really need an explanation. Thank you.
0answers
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### 2D FFT with unit stride data access?

I am trying to design a large 1D FFT by splitting N into two smaller FFTs of sizes N1 and N2. This is common approach stemming from the Cooley Tukey Algorithm. My FFT is taking time sampled data in ...
0answers
15 views