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1500 questions
12
votes
5 answers
Why is random noise assumed to be normally distributed?
From residual in the linear regression to noise in signal processing are assumed to be normally distributed? By considering them as normally distributed we are kind of telling the pattern in the noise but shouldn't noise be considered random. This…
zeal
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12
votes
2 answers
Subtracting sensors output that have mutual inductnace between them
Background: The software that i use to anaylze my signals is matlab. I have two audio signals that were recorded using two magnetic sensors. Lets call one sensor A and the other one B. A and B have mutual inductance between them.
While sensors A…
user1017064
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12
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2 answers
Bounds of the derivative of a bounded band-limited function
Let $f(t)$ be a function with properties:
$$\begin{array}{ll}
t\in\mathbf{R}&t\text{ is in reals}\\
f(t)\in\mathbf{R}\text{ for all } t&f(t)\text{ is in reals}\\
|f(t)|
Olli Niemitalo
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12
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9 answers
Where is the flaw in this derivation of the DTFT of the unit step sequence $u[n]$?
This question is related to this other question of mine where I ask for derivations of the discrete-time Fourier transform (DTFT) of the unit step sequence $u[n]$. During my search for derivations I found one which is amazingly simple. I first saw…
Matt L.
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12
votes
3 answers
Transmit data through sound between 2 computers (very close distance)
I'm writing an example on transmitting data through sound betwwen 2 computers. Some requirements:
The distance is very close , i.e the 2 computers are basically adjacent to each other
Very little noise (I do not think my teacher would turn on a…
Dang Manh Truong
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12
votes
1 answer
What is an exact measure of sparsity?
I am currently working on compressed sensing and sparse representation of signals, specificly images.
I am frequently asked "what is sparsity definition?". I answer "if most elements of a signal are zero or close to zero, in some domain like Fourier…
MJay
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12
votes
2 answers
Filtering vs Compression Paradox
Filtered signal leads to bigger compressed files.
#1. Original Situation
I have an original signal as a column data matrix n channels data x:mxn (single), with m=120019 the numer of samples and n=15 the number of channels.
Also, i have the filtered…
Brethlosze
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12
votes
1 answer
Applying A-weighting
I want to calculate the loudness of a given signal and I've come across this thread. I'm slightly confused about the A-Weighting aspect of it. I can't post images, but I think this site has the formula I need. (Wa = 10log...)
What I don't understand…
TryNCode
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12
votes
3 answers
What does correcting IQ do?
Some software (for example SDR Sharp) has a "Correct IQ" option. This is used to get rid of the DC spike in the middle of the display. What does this setting do to the signal? What is wrong with the IQ values that needs to be corrected?
Ken - Enough about Monica
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12
votes
1 answer
Are there preferred patterns for creating texture on objects to aid computer vision?
In the comment to this answer using a laser diode and diffraction grating to provide texture on a surface was suggested to aid in height calculations in a computer vision system.
I believe the pattern that I'm familiar with is projecting a…
Stephen
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12
votes
4 answers
DFT - Removing window effect in spectral domain with convolution
I was thinking about the DFT windowing subject and a thought came to my mind. A DFT will yield the spectrum of a signal convoluted with spectrum of the window used, therefore having a main lobes and side lobes.
I figured it would be possible to…
Pier-Yves Lessard
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12
votes
2 answers
How to demodulate an OFDM signal
I'm looking at decoding an OFDM signal which consists of 6 carriers (or tones) which are BPSK modulated and a pilot tone which aids tuning. This is the first time I have worked with OFDM so I need to know if I'm approaching this in the right…
IanW
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12
votes
3 answers
How to detect "fast" changes in signal processing
I'm working on a project where we measure the solderability of components. The measured signal is noisy. We need to process the signal in real time so that we are able to recognize the change that begins at the time of 5000 milliseconds.
My system…
Petr
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12
votes
2 answers
Pedestrian counting algorithm
Currently I am developing a pedestrian counter project (using OpenCV+QT on Linux). My idea about the approach is:
Capture Frames
Do Background Subtraction
clear noises (erode, dilate)
find blobs (cvBlobslib) - foreground objects
For each blob, set…
bahadir
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12
votes
1 answer
What's the advantage of adaptive IIR filter against FIR?
Adaptive IIR filters is not straightforward, and may be unstable. Many people say that adaptive IIR filters use less coefficients than FIR filters. What I'm curious about is how many coefficients can IIR save?
I tried to use adaptive IIR filters to…
Alexander Zhang
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