Linked Questions
21 questions linked to/from Why should I zero-pad a signal before taking the Fourier transform?
7
votes
1answer
6k views
What happens when N increases in N-point DFT [duplicate]
I am curious about DFT, and I wrote a simple MATLAB code to test what happens when $N$ increases. I took a rectangular signal with length $L=15$, an then found th DFT of 16, 32 and 64 points. I looked ...
0
votes
1answer
843 views
What does it mean when you zero pad data and why does one do it? [duplicate]
I am struggling to understand what effect zero padding data would have on EMG data. How does it improve the signals? Any help in simple terms that's not too mathematical would be greatly appreciated!
2
votes
1answer
338 views
What Is the Point of Doing the Zero Padding? [duplicate]
What are the advantages and disadvantages of doing Zero-padding, in particular the case of speech signals?
65
votes
7answers
107k views
How do I implement cross-correlation to prove two audio files are similar?
I have to do cross correlation of two audio file to prove they are similar.
I have taken the FFT of the two audio files and have their power spectrum values in separate arrays.
How should I proceed ...
9
votes
2answers
20k views
Why images need to be padded before filtering in frequency domain
In image processing books , we are told that Images need to be padded while doing filtering in the frequency domain. Why we need that zero padding ?
5
votes
3answers
5k views
Zero Padding in FFT
whats is the effect of pading zeroes to a sequence in FFT?
for eg: x[n]=[2 3 4 5] corresponds to X[K]=[14 -2+2i -2 -2-2i]
while x[n]=[2 3 4 5 0 0 0 0] corresponds to X[K]=[14 0.58-9.65i -2+2i -3.414+...
20
votes
2answers
6k views
Frequency-domain zero padding - special treatment of X[N/2]
Suppose we wish to interpolate a periodic signal with an even number of samples (e.g. N=8) by zero-padding in the frequency domain.
Let the DFT X=[A,B,C,D,E,F,G,H]
...
5
votes
3answers
6k views
Zero-pad before or after windowing for FFT
What's the correct way. Should I zero-pad a signal before or after applying a windowing function?
5
votes
3answers
10k views
Advantages/disadvantage of zero padding
I would like to know what are the advantages/disadvantage of zero padding with respect to frequency measurement and amplitude measurement
8
votes
2answers
9k views
FFT of size not a power of 2
My question is regarding the input size of a signal which is not a power of 2 and we have to take the fft of it. Some solutions say that suppose if we want to take the fft of 1800 we should zero pad ...
3
votes
3answers
3k views
disadvantages of FFT, it can not extract enough frequencies without enough samples
Let's say sampling rate is $Fs = 44\mathtt{kHz}$, now I have $N = 2048$ samples, then I can get $N/2 + 1 = 1025$ frequencies.
I'm confused by Matlab's FFT documentation that says the frequencies are ...
3
votes
2answers
1k views
The frequency response function (FRF) fails to detect the antiresonance of a system
I am trying to identify a vibrational systems by computing the frequency response function (FRF) of the system when a chirp signal is applied to its input. After comparing the FRF computed and the ...
1
vote
2answers
1k views
Mathematical justification for zero padding?
This question asks what's the point of zero padding. The accepted answer is certainly very insightful, but I don't understand a big chunk of it:
Zero padding allows one to use a longer FFT, which ...
0
votes
0answers
1k views
Autocorrelation and FFT : avoid zero-padding
Some posts evocate the computation of convolution or cross-correlation using FFT and zero-padding the temporal signal.
I want to compute the autocorrelation of a 3D array using FFTW (2 dimensions are ...
0
votes
2answers
657 views
What proportion of a padded FFT should be actual values
For a given signal, I've been told that you can pad the vector with $0$s at the end to get a larger DFT, and as a result get more precision in frequency bins.
What are the limits to this approach?
...