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1500 questions
14
votes
2 answers
Inverse polyphonic chord recognition
Polyphonic music transcription does not currently appear to be a solved problem.
How about the inverse of a small portion of the problem. Are there any kind of spectral characteristics (from an STFT) that can be used to eliminate some musical…
hotpaw2
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14
votes
4 answers
basic hsb skin detection, neon illumination
i hope this is the right place to ask. otherways sorry for my mistake and pleace advice me a better site.
i'm trying to implement a super simple skin detector using some range of hsb image. i'm using approach described here and here.
i'm try to use…
nkint
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14
votes
7 answers
The difference between DFT and DFS
In the literature, I've found that DFS and DFT are one and the same. If they are one and the same why to use two different names for them? If there is really a difference what is it and what is the significance of discrete Fourier series?
phanitej
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14
votes
3 answers
Designing Butterworth filter in Matlab and obtaining filter [a.b] coefficients as integers for online Verilog HDL code generator
I've designed a very simple low-pass Butterworth filter using Matlab. The following code snippet demonstrates what I've done.
fs = 2.1e6;
flow = 44 * 1000;
fNorm = flow / (fs / 2);
[b,a] = butter(10, fNorm, 'low');
In [b,a] are stored the filter…
Nicholas Kinar
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14
votes
1 answer
How can one improve the robustness of adaptive beamformers to signal mismatches?
Compared to standard (conventional) beamformers, adaptive beamformers such as minimum variance distortionless response (MVDR) have much better resolution and interference nulling capabilities. Briefly, the MVDR beamformer is as follows:
If…
Lorem Ipsum
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14
votes
1 answer
Estimating onset time of a tone burst in noise?
What techniques might one use to estimate the onset time of a sinusoidal tone burst in a noisy signal?
Assume the tone burst has a known fixed frequency (but unknown phase) and a very sharp rise time, and that the goal is to estimate the onset time…
hotpaw2
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14
votes
3 answers
What is IQ Data?
I have no background in telecommunication. Could anyone please explain to me what is the IQ data in telecommunication? It will be best to explain it with some basic analogies. Many thanks!!
sedter
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14
votes
2 answers
How can I change the formula to detect the barcode in every angle? - MATLAB
How can I change the formula to detect the barcode in every angle?
rgb = imread('barcode4.jpg');
% Resize Image
rgb = imresize(rgb,0.33);
figure(),imshow(rgb);
% Convert from RGB to Gray
Igray = double(rgb2gray(rgb));
% Calculate the…
Kim
- 143
- 5
14
votes
3 answers
STFT and DWT (Wavelets)
STFT can be successfully used on sound data (with a .wav soundfile for example) in order to do some frequency-domain modifications (example : noise removal).
With N=441000 (i.e. 10 seconds at sampling rate fs=44100), windowsize=4096, overlap=4, STFT…
Basj
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14
votes
4 answers
Are complex exponentials the only eigenfunctions of LTI systems?
Is there an example of an eigenfunction of a linear time invariant (LTI) system that is not a complex exponential? Justin Romberg's Eigenfunctions of LTI Systems says such eigenfuctions do exist, but I am not able to find one.
Vinod
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14
votes
2 answers
Improving SNR using DSP techniques
I am building an optical OOK (On off Key Ring) system without a carrier frequency. [However I have a guard time in between symbols, so a consecutive "1" messages will result in a pulse train as opposed to DC, see image]. Essentially, the presence…
Frank
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14
votes
1 answer
Comparison between Fourier transform, short-time Fourier transform and wavelets
What is the difference between the Fourier transform, short-time Fourier transform and wavelets?
student
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14
votes
4 answers
Is the discrete Gaussian kernel an eigenfunction of the DFT?
So the Gaussian function is an eigenfunction of the Fourier transform because it transforms into itself, right?
But this isn't true for the sampled Gaussian in the DFT because the tails of the function are truncated, right?
Wikipedia describes a…
endolith
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14
votes
6 answers
Compressive Sensing Through MATLAB Codes
I am new to the topic of compressed sensing. I read a few papers about it by R.Baranuik, Y.Eldar, Terence Tao etc. All these papers basically provide the mathematical details behind it, i.e., Sparsity, RIP, L1 norm minimisation etc. However, can…
USC
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14
votes
2 answers
FFT frequency resolution
I'm having some problems understanding the FFT. Is the frequency resolution in the spectrum calculated as
$\frac{\textrm{sampling rate}}{\textrm{number of FFT points}}$ or $\frac{\textrm{sampling rate}}{\textrm{0.5 * number of FFT points}}$?
Asking…
argh
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