Questions tagged [signal-processing]
The subfield of electrical engineering that focusses on analysing, modifying, and synthesizing signals such as sound, images, and scientific measurements.
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What should the cross-correlation of two signals look like if their difference is non-significant?
I have some signal data from my lab that I want to present but I want to be able to say whether the signals I have are significantly different or not. I thought I could use cross-correlation. I ...
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Why need for 96kHz, 192kHz audio? [closed]
Human can hear 20-20,000 Hz waves, so by Nyquist theorem it's sufficient to sample audio with 40 kHz. Indeed, 44.1 kHz widely used. But what do we need higher sample rates for? 96 kHz, 192 kHz are ...
user22330
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Energy of a signal
"The energy" of a signal $x(t)$ is defined as :
$$E_s = \int_{-\infty}^{\infty}|x(t)|^2$$
Why is it called energy if it's not homogeneous to energy ?
What does it actually represent ?
Parseval's ...
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If halving signal strength is only a 3db drop, why can't cell phones be much lower powered?
My phone can receive a signal that's -90dBm. That's roughly one-billionth of a milliwatt. Cutting a signal's strength in half only drops the signal by 3dBm. Apart from slightly higher range, is there ...
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Why can't we use the Neyman-Pearson likelihood ratio directly?
If you have a bunch of events and would like to choose a cut to distinguish background and signal, you can take the likelihood ratio
$$
\lambda(\vec x) = \frac{f(\vec x| s)}{f(\vec x| b)}
$$
and the ...
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What does it mean to have two phase coherent signals at different frequencies?
Just as the title states, I don't understand what it means to have two different signals that are phase coherent but are at different frequencies.
I am attempting to implement a MSK modulator in ...
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Optical signal filters
Are there any optical filters which filter the signal's frequency and not based on the wavelength of the light? So what I mean is, if I have a modulated/pulsating light signal riding on a large DC ...
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What are some good resources for learning photonics?
Including the generation, transmission, modulation, signal processing, amplification, and detection/sensing of light, I am interested in getting a good understanding of photonics. Does anyone have any ...
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Bandwidth of telephone wire
Internet providers try to sell us the more and faster "fast internet" - 15Mb, 40Mb, 100Mb, and so on. But it's well known that the bandwidth the channel (in the most cases it's the telephone wire) ...
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Why is bandwidth, range of frequencies, important when sending wave signals, such as in radio?
So in wired/wireless networking and radio, signals are sent in form of wave. Then the concept of bandwidth comes in, which is the difference between highest frequency and lowest frequency in a signal. ...
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Compression vs Rarefaction in Sound Waves
I am currently looking into solutions for Sound Classification, and I came across Ludvigsen's methodology (if anyone wishes to refer to it).
The problem is that a sample graph of amplitudes in one of ...
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A sonar continuously emits x(t), a general but known waveform and is reflected by a target. hypothetical question
A sonar continuously emits x(t), a general but known waveform that is reflected by a target and received by the sonar. Both the sonar and the target move in the 3-dimensional space in a general but ...
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Why does a wall act as a low-pass filter?
Learning about the fourier transform and its connection to filtering/convolution got me curious about naturally occurring filters.
Why/how is it that brick walls naturally act as a low-pass filter (...
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Spatial Resolution in Magnetocardiography
In the science paper called Development of an optical cardio-magnetometer by George Bison, it is mentioned that spatial resolution of 10-20mm is required for mapping MCG signal(page 52). What does the ...
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Image Reconstruction:Phase vs. Magnitude
Figure 1.(c) shows the Test image reconstructed from MAGNITUDE spectrum only. We can say that the intensity values of LOW frequency pixels are comparatively more than HIGH frequency pixels.
$$
f(x,y)=...
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