Questions tagged [information-theory]

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2
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3answers
252 views

Is there a proof that equal bandwidths have equal information-carrying capacity?

Consider a continuous channel, band-limited to the $[f_{\text{min}},\,f_{\text{max}}]$ frequency window. A well-known statement says that, as far as the dependence on the frequencies, the information-...
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2answers
127 views

What are the fundamental reasons that suggest us to minimise transmission power for energy-efficient radio link design?

My question in short: Under which scenarios minimising transmission power is beneficial in terms of transmitter energy-efficiency? is there any fundamental reason to keep a low-power oriented design ...
2
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1answer
220 views

Mutual information of $ \infty $-PAM

I'm trying to compute using matlab the mutual information for an $ \infty $-PAM input (the limit of a very dense PAM constellation) for a range of snr and I got stuck. I'm working with a real-valued ...
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3answers
600 views

Is concept of “bit” in computer programming similar to the concept of “bit” in information theory?

until today I knew that one bit is a variable, or a space in memory that can hold a value of either One (high) or Zero (low). This is the concept I learned from studying computer programming, ...
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1answer
70 views

Can somebody help me with some very basic questions about the fundamentals of information theory?

I just started to study information content of the source and there are some very fundamental topics I am not really clear on. These might be a long question or a series of questions. Please help me. ...
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2answers
445 views

What is the entropy for these cases?

This question stems from an article, "Entropy estimation of symbol sequences" download link where the abstract mentions the need for using symbols in information theory. Random chains of ...
4
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1answer
262 views

Image registration / fusion optimal similarity metrics

I have a theoretical question about optimal similarity metrics for comparing data sets. In reading this linked paper, pp. 488-489 [1], I read the following 2 interesting statements. On page 488: ...
1
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1answer
192 views

Filters performance analysis

I am working on some experimental data which, at some point, need to be time-integrated and then high-pass filtered (to remove low frequency disturbancies introduced by integration and unwanted DC ...
0
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1answer
296 views

Relation between SER and the channel capacity

Is there a relation between Symbol Error Rate (SER) and the channel capacity? What is {Modulation Order x (1-SER) / symbol duration [bps]} called?
1
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1answer
299 views

Dominant eigenvectors of an unknown matrix

Do you have any idea about how we can find the principal eigenvectors of an unknown matrix ${H}$? The elements of $H$ are unknown in general. If you are familiar with channel estimation procedure in ...
2
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1answer
218 views

Effect of noise and entropy

Relation of Entropy and SNR : Based on this question and answer, I had another question that struck me and I am curious to know, if somebody can shed some light, on the following situation: $y= ...
3
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1answer
178 views

Difficulties in understanding mutual information concept

What does mutual information (MI) convey? If 2 signals are independent then MI is zero; What does this imply and mean in the case of mutual information of error, and in general definition of MI and ...
3
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1answer
110 views

Conceptual question on entropy and its relation to information

Learning Informative Statistics: A Nonparametric Approach paper presents an approach to parameter estimation by entropy minimization. There are other related works "Minimum-entropy estimation in semi-...
0
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1answer
131 views

How to Detect a Inhomogeneity Region in Image

I have an image that includes object and background. However, the object appears some inhomogeneity region due to illumination. My work is that how to detect inhomogeneity region. Which is feature can ...
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2answers
470 views

Confusion about shannon's entropy of the grayscale image after lossy compression

I have a .pgm format 480 * 640 gray scale image named 'columns.pgm'. Using PCA (principal component analysis), by preserving 40 principal components I compressed original image with 1218 KB to 301 KB ...
0
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1answer
93 views

Entropy when having symbols with same probability

I am trying to work out this problem: Assume that we are transmitting data from a dictionary of 15 symbols. Let the probability of sending one symbol be the same as that of sending any other symbol....
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0answers
367 views

Extracting features from a signal: a 21st century approach?

I have a discrete signal of random length (let's say between 500 and 800 in time). This signal has an important information which I want to collect and to put it together in a feature vector to train ...
0
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1answer
42 views

Capacity computation in Costa sheme

I can not understand the following sentences, could you please anyone guide me ? "Comparing with the embedding in audio signals, the usable bandwidth is greatly reduced, from 22.05 kHz to 4 kHz. ...
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2answers
111 views

Transmission Line Information Loss

Suppose we have a communication channel that has a bit-error rate of 50% and the bits are flipped at random such that the receiver has no efficient way to tell which bits have been flipped and there ...
11
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1answer
3k views

Relationship between entropy and SNR

In general any form of enropy is defined as uncertainty or randomness. In a noisy environment, with increase in noise, I believe that entropy increases since we are more uncertain about the ...
3
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2answers
1k views

Meaning of channel capacity in the AWGN channel

I understand the concept of channel capacity as the maximal rate of the channel code I can apply without making a mistake in the receiver, in that sense the capacity is between 0 and 1. What I don't ...
2
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2answers
367 views

Conceptual definition of entropy

What is the conceptual difference between Kolmogorov-Sinai entropy, Shannon entropy and Boltzmann entropy? Are they interchangeable and mean the same? Where can I find a good lucid explanation about ...
5
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1answer
2k views

Why is mutual information symmetric but conditional entropy isn't?

Conditional entropy $H(X|Y)$ tells us how much the average uncertainty about a channel input $X$ is after observing channel output $Y$, and mutual information $I(X,Y)$ measures how much information ...
3
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1answer
300 views

Mathematical model of equivalent-time sampling, the resulting unevenly spaced periodic signal, and its interpretation

I sample a continuous signal $s(T)$ over time. This leads to $s[t]$, which depends on several factors of which some are (pseudo-) periodic. I am interested in the effect of one such periodic factors ...
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0answers
96 views

transmitting data using phase modulation of two sine waves passed through distortion

I have two sine signals with frequencies f1 and f2, and phase p1 and p2. I modulate the phase of these signals to transmit two symbols simultaneously, chosen from the set [0,1,2,3]. For example, I ...
2
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2answers
215 views

Entropy Of A Symbol

Does the entropy of a symbol represent the most optimal average number of bits that can be used to represent a symbol? For example take the example of tossing a coin: $$ H_{source} = -p_{head} ...
5
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1answer
138 views

Does any error correction code still work in such situation?

I'm looking for a kind of error correction code or solution that can correct my codeword in this case: My message holds $k$ bits, and $2k$ bits codeword (rate is $1/2$) is produced by the generator ...
6
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2answers
6k views

What are some typical lossless compression ratios?

A client was trying to send me 250 GB worth of files. After attempting various ways of sharing the data, he sent me a zipped folder only 4 GB in size. That sounds like too much compression to me--I ...
2
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1answer
1k views

What is Shannon's source entropy

Suppose that ${X_n; Y_n}$ is a random process with a discrete alphabet, that is, taking on values in a discrete set for $n$ data length. They correspond to the input and output of a communication ...
6
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1answer
166 views

Issues related to entropy

I have long been faced with the confusion regarding entropy and would be obliged if the following are answered in less technical jargon. Following the link Different kinds of entropy raises the ...
5
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1answer
148 views

Mutual Information, is this calculation correct or should I contact the author about fixing it?

Background information According to Cover's text book on information theory Mutual Information is calculated as: $$(1) I(W;C) = \Sigma_k\Sigma_i P(C_k,W_i)log(\frac{P(C_k,W_i)}{P(C_k)P(W_i)}) $$ ...
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2answers
4k views

What is the meaning of Mutual Information beyond the numerical calculation?

Beyond the raw equation for calculating mutual information, what does it mean in physical terms? For example: From Information Theory, we know that entropy is the smallest loss-less compression scheme ...