The Stack Overflow podcast is back! Listen to an interview with our new CEO.

# 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.

244 questions
Filter by
Sorted by
Tagged with
5k views

### How does FFT work?

For five years I tried to understand how Fourier transform works. Read a lot of articles, but nobody could explain it in simple terms. Two weeks ago I stumbled upon the video about a 100 years old ...
73 views

### Imaginary Numbers and DFT

I'm not a math guy per se, but i am trying to understand the DFT. I get to the point where imaginary numbers are used with Euler's formula. What I don't understand is why we need an imaginary plane ...
3k views

### Solve Poisson Equation Using FFT

I am trying to solve Poisson equation using FFT. The issue appears at wavenumber $k = 0$ when I want to get inverse Laplacian which means division by zero. We have ${\nabla ^2}\phi = f$ Taking ...
70 views

### Determine the shift in tonal center of a piece of music.

Starting with a sampled audio signal of acapella vocals, I am interested in determining the shift in the tonal center of the music through the performance. As a choir progresses through a ...
186 views

71 views

### Value Proposition of Fourier Analysis?

I am a software engineer trying to wrap his head around Fast Fourier Transform (FFT). Specifically, I need to implement it as part of some software I am writing. Now I can handle the implementation of ...
53 views

### dimension after fast fourier transform

I am doing a frequency analysis. Reading some literature I have seen that when you perform an fft on a time history of a variable, the dimension of this variable remains the same also after the ...
100 views

96 views

### Intuition of fft over time to frequency

I understand how FFT (DFT) works. It acts as a change of basis. However, while many websites describe fft as a method that convert time domain stuff to frequency domain stuff, I still do not know why ...
120 views

### How to get the frequency of a time-domain signal with limited sample length?

Let's say there is a signal who only has one peak in its power spectrum. I would like to know the frequency at which the peak is (the magnitude of power is not important to me). But I only have very ...
Solve the following non-homogenous heat equation:$$\frac{\partial u}{\partial t} = a^2 \frac{\partial ^2 u}{\partial x^2} + \epsilon \sin(k_0x)$$ on the domain $-\infty \lt x \lt \infty$, with ...