New answers tagged dft
2
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Why do DFT frequency buckets need to be divided by sample period?
I might be late to this question but the problem with frequency bins isn't about normalization. After your FFT, each frequency bin is calculated as
$$ f_k = \frac{k}{N} \cdot f_\mathrm{s} $$
where $f_\...
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Reconstructing the original signal from its DFT
I need to reconstruct $x(t)$ from its DFT $X(k)$.
I don't want to sound flip here but the way to do this would be to use the inverse DFT, i.e.
$$x[n] = \frac{1}{N} \sum_{k=0}^{N-1} X[k]e^{j2\pi\frac{...
- 42.5k
0
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Scaling Property in DFT
But 1/ab is scaling the magnitude.
Here limits are for the indices.
0
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Finding Discrete Fourier Transform (DFT) for different DFT size
This exercise is aimed at showing that zero-padding in the time domain interpolates the frequency domain. Since this is homework, I'll give you the beginning of the solution.
Just like you did, start ...
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0
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Real discrete Fourier transform
This is a very well presented question. I always had problems with DFT stuff, but what I learned using it is that complex numbers decrease your work by more than half:
you do not deal with $a$ and ...
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Accepted
What's the distribution of the DFT of a real-valued, zero-mean, normally distributed random vector?
As the DFT of real $X$ is conjugate symmetric, $\hat{X}$ is not N-dimensional jointly Gaussian and neither your two distributions is correct.
Representing the N-dimensional DFT by a $2N$ dimensional ...
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FFT: Sinewave frequency displacement when zero-padding
The Fourier transformation (FFT is a faster method with the same result) attempts to replace an infinitely long signal with a combination of a finite number of sin and cos functions. The frequencies ...
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6
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Accepted
FFT: Sinewave frequency displacement when zero-padding
(I show only positive frequencies):
which is part of the problem here :-)
You would get the expected behavior if you used a complex sine, i.e. $x[n] = e^{j2\pi\frac{n}{N}}$ but a sine wave actually ...
- 42.5k
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