# Questions tagged [fourier-transform]

The Fourier transform is a mathematical operation that decomposes a function into its constituent frequencies, known as a frequency spectrum.

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### How to understand the relationship between the filter time constant and the half-power cutoff frequency

I learned that the time constant can be computed as $\frac{1}{2 \pi f_0}$, where $f_0$ is the half-power cutoff frequency of a high-pass filter. However, I was wondering how the time constant and the ...
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### detection of periodicities in n-dimensional signals

Generally speaking, what analyses are necessary and sufficient for the detection of periodicities in an n-dimensional signal amounting to a discretely sampled density distribution over n-dimensional ...
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### interpolate 1D signal depending on 3D parameter space

I have a 1D array of data d(x,p) in which a number of "bumps" or "dips" appear and/or move in the spacial dimension x, depending ...
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### Amplitude of frequency bin in FFT doesn't match time-domain amplitude

I have a sinusoidal current that I am sampling at about 357k SPS. The current signal is about 3A pk-pk @ 750hz (top figure). I am wondering why when I take the fft using numpy/scipy's fft function, ...
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### Get I and Q components from a signal (multple frequency signal)?

Is there anyway to get the I and Q components from a signal in the time domain? The signal has multiple frequencies. So far I have been doing this in a SIMPLE situation: Fast fourier transform to ...
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### Software to extract frequency spectrum data from an audio file

I've been trying to learn how computers recognize musical notes, and I found apps like spectrogram which shows the frequency spectrum of a sound, but what I need is the data which is plotted or the ...
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