All Questions
Tagged with signal-processing information
10
questions
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Maximum bitrate density of a shared medium
I'm not a physicist, so my apologies if this isn't worded correctly, or if it even is a valid question.
I was recently learning how WiFi works and how the slowest devices on a channel can slow down ...
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9
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2
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What is meant by 2D fourier transform of an image?
I have some questions about this interesting concept I came across about 2D Fourier transform, please...
Firstly, the Fourier transform of a 1D signal (such as a sound recording) is as follows:
The ...
user315366
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Is it possible to use a distributed camera array to fake an interferometric sensor without phase data?
Astronomical interferometry is a technique which uses multiple small telescopes to mimic one giant telescope. It requires the phase of the light to be captured for it to work. It is widely used in ...
0
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Apparent superluminal signals, is it as simple a variation on the following?
I know that astronomers observe jets that apparently move faster than light but really don't. I think I can simulate something that looks superluminal using just a bunch of x-mas lights and i am ...
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2
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Multiple frequencies [closed]
could someone please inform me how it is possible to send multiple frequencies down one wire? I’m referring specifically to a communication protocol known as HART. It seems they send a 4-20mA signal ...
- 29
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High speed data transfer over a fiber optic cable
Can someone please explain how can we transmit very high speed data (e.g. $10~\rm Gbps$) over fiber optics, knowing the fact that the wave that travels through the fiber is an optical wave (in the ...
- 161
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What is the relationship between bitrate and bandwidth for optical channels? [closed]
I would like to know what the relationship between bitrate and the width of spectrum that needs to be assigned to an optical channel is; assuming the channel uses an OOK modulation format such as RZ ...
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Exceed Information limit with a Bigger Codebook? [closed]
I was reading about how there is an upper limit to how fast information can be transmitted over a given channel - the Shannon–Hartley theorem.
I was wondering how this theorem works with codebooks. ...
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5
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What is the interpretatation of individual contributions to the Shannon entropy?
If $X=\{ x_1,x_2,\dots,x_n\}$ are assigned probabilities $p(x_i)$, then the entropy is defined as
$\sum_{i=1}^n\ p(x_i)\,\cdot\left(-\log p(x_i)\right).$
One may call $I(x_i)=-\log p(x_i)$ the ...
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6
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2
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Why isn't data lost when sent over large distances?
I was thinking about how information is sent, for example through the atmosphere. There are plenty of obstacles, as well diffraction, etc.
Still, no information is lost. How is information sent to ...
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