Questions tagged [coding]

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Approximating variable-length coding by "aggregating" fixed-length coding

Consider the problem where I want to quantize a univariate standard Gaussian with two bits, and the objective is to minimize MSE reconstruction loss. According to these slides, the Lloyd algorithm and ...
nalzok's user avatar
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Is it better to do fixed-length Lempel Ziv Encoding or variable length?

I performed variable-length LZW encoding in Matlab on a large set of text where my dictionary looks like this (size = 28): ...
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Z-Transform of a Precoder with XOR

I am reading a paper called "Design and Comparison of Three 20-Gb/s Backplane Transceivers for Duobinary, PAM4, and NRZ Data" and got stuck on seemingly easy thing, how the Z-domain ...
Mohamed Osama's user avatar
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Is this an appropriate Huffman code?

The problem is question 6.25 from Proakis, Communication Systems Engineering (2001) Design a ternary Huffman code, using 0, 1, 2 as letters, for a source with output alphabet probabilities given by {...
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Find rows that meet all criteria in SQL

I'm unable to create a SQL query that does the below: Say for instance Person A participated in Event 1 and Event 2. Person B participated in Event 1. Person B participated in Event 1 again Person C ...
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RS FEC correct more than t/2 errors sometimes... why is this happening?

According to the Reed-Solomon Wikipage, the RS code can correct up to $\lfloor\frac{t}{2}\rfloor$. While I was playing around with Reed-Solomon FEC (github repo), I noticed that sometimes the RS(544, ...
Emm386's user avatar
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1 answer
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What is the best coding strategy?

There is a dataset of $N$ elements, each represented by $K$ bits. Now due to hardware limitations to reduce memory for storage, they have to be reprocessed into $K'$ bits each, and $K'<K$. What is ...
c1119's user avatar
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Minimum distance question

I´m reading a paper on Miller codes and I´m having trouble calculating the minimum distance out of a state diagram. The paper states in Fig. 3. that "it is easy to verify that dmin for these ...
Elias4l's user avatar
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Other Examples of Complete Orthonormal Systems

I am interested in other examples of finite and complete orthogonal basis. I am not confident in my use of the term “complete”, so what I mean specifically is a set of basis vectors that can be used ...
Dan Boschen's user avatar
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Why is Line coding called "Line coding"?

Guys do you now why line coding also called digital base band modulation named "line coding" where does it come? and how is the name related to modulation
yohans hailu's user avatar
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1 answer
153 views

Optimal idle or frame sync symbols for OQPSK

Okay, everyone here knows that my thing was audio and that I have never gotten paid to do anything regarding communications systems. So, while I know a thing or two about DSP and even a little about ...
robert bristow-johnson's user avatar
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1 answer
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Shortened linear codes

I've been working on my linear code assignment in my coding theory course and I have encountered a problem I would like to get help with. the question is described below. I will try to expalin what I ...
Ran Greidi's user avatar
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Adding FEC to sporadic burst of Huffman-encoded words

This question may be interpreted as a second part of this other question. Basically, if we encode our data using Huffman's encoding and we want to introduce some FEC afterwards, unless we use a ...
user3141592's user avatar
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Having trouble interpreting z-transform description of a predictor from a codec paper

I've been looking at the opus paper (https://arxiv.org/pdf/1602.04845.pdf); in particular, in section 4.1, they describe the predictor for the current band energy based on energy from both the current ...
ferris's user avatar
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318 views

Optimal FEC option for extremely low SNR situation

I am new to this site, which I joined with the aim of finding someone to help me with a little doubt. I am trying to design a system that must be able to work at extremely low (the lower, the better, ...
user3141592's user avatar
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201 views

understanding FIR SRRC filter with memory implementation in C

I translated the Matlab QPSK receiver/transmitter into real-time C code that I have running on a PlutoSDR platform. QPSK receiver/transmitter I wrote the square root raised cosine filter for the TX ...
yellow_watermelon's user avatar
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Understanding of Reed Solomon code

We send the data in bytes to the RS Encoder block. The RS Encoder block encodes the data with the Reed Solomon (225,223) code. It waits for 223 bytes and after this encode them to make a codeword of ...
Anna Koroleva's user avatar
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1 answer
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Multi-bit gold code

Is the multi-bit gold code resulted from a xor of two different multi-bit m-sequences will still maintain its statistical property (bounded correlation, distribution of 1 and 0) ?
Eagle Shou's user avatar
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How to apply an offset to a complex exponential without chopping it off?

I am trying to encode a bitstream as offset in a complex exponential, but when I do, the sinusoids get chopped off. Do I need to apply a lowpass to the bitstream or is there a more elegant way? ...
neolith's user avatar
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Transition table / matrix for convolutional encoder K=3 understandings

Im trying to understand convolutional encoder $K=3$ , and I almost understand it but still confused about what's called transition matrix which in other words it means what input value ($0$ or $1$) ...
Maher's user avatar
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3 votes
1 answer
932 views

Finding preferred pair of $m$-sequence for Gold code

I would like to find a preferred pair of $m$-sequence of degree 34 (not a multiple of 4) for Gold code. However, I am lost when I am checking William Wesley Peterson's table in his Error-correcting ...
Eagle Shou's user avatar
1 vote
1 answer
892 views

Differential Encoding for M-PSK

Confused about a few topics w.r.t. differential encoding/decoding. First, consider the below BER curve taken from wikipedia ( https://en.wikipedia.org/wiki/Phase-shift_keying ) comparing BPSK/QPSK and ...
user67081's user avatar
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1 vote
1 answer
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Most reliable way to decode PAM2 signal with unknown signal levels?

I assume this is pretty much a standard problem. I have a PAM2 signal that comes from a complex envelope (i.e., it is not zero-centered) and is heavily imposed by noise. This shows 20 different ...
divB's user avatar
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-1 votes
2 answers
79 views

Can we broadcast two messages using NOMA?

Is it possible for a transmitter to broadcast two messages to a set of receivers at the same time using superposition coding (Non-Orthogonal Multiple Access - NOMA)? A transmitter has two messages $...
Azz's user avatar
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2 votes
2 answers
583 views

Interleaving or randomisation?

I am trying to implement a digital communication system as a learning exercise. For error correction, I am using two concatenated codes (RS and convolutional). However, I read that, in order to reduce ...
user3141592's user avatar
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1 answer
370 views

What's the difference between quantization and coding?

From what I understand quantization takes an analog signal and assigns numerical values to it as convert it to a discrete signal. However coding converts a signal into binary. It seems like coding is ...
Leftover Salad's user avatar
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1 answer
347 views

Bandwidth and BER of FM0 encoding

What is the bandwidth (i.e., the lowest possible bandwidth) and BER for FM0 encoding? To be precise, this is my example of an FM0 encoded waveform: There is always a transition between each bit. For ...
divB's user avatar
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2 answers
831 views

Definition of Perfect Code (and example of Hamming Code)

Let's consider the following sentences about coding a message before transmitting it in a communication system (here you find the complete pdf) First question: can you explain me these two ...
Kinka-Byo's user avatar
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1 vote
0 answers
250 views

Capacity achieving codes for BPSK at low SNR

I don't know a lot about comm system design. I have an AWGN channel and low SNR (-3dB). Bandwidth is constrained to some maximum, B. I would like to know good choices of modulation and coding to ...
rhz's user avatar
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1 answer
35 views

How good is the Leech lattice for AWGN coding or MSE quantization of Gaussian sources?

Anyone know where to find graphs showing how well it works vs other schemes? thanks
Christian Chapman's user avatar
-1 votes
1 answer
70 views

STBC Rank Criteria Explanation

I am learning about space-time block coding and I am trying to understand why the rank criteria is a good measure of diversity gain. I know that we want to maximize the distance between codewords $X_i,...
rytse's user avatar
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1 vote
1 answer
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What is the Asymptotic Equipartition Property (AEP)?

I am currently studying about Polar Codes in 5G standard and while reading my paper I found something called AEP which is required for channel coding. I surfed the web but didn't found a satisfying ...
Himanshu Sharma's user avatar
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1 answer
103 views

Prefix code of symbol pairs

An input sequence consists of two symbols, each independently and randomly chosen from a set of symbols with known associated probabilities. Each symbol is independently encoded using a prefix code ...
Olli Niemitalo's user avatar
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1 answer
37 views

Randomized prefix code

An input symbol is randomly chosen from a set of symbols with known associated probabilities and encoded using a prefix code that minimizes the expected codeword length. Is it possible to further ...
Olli Niemitalo's user avatar
10 votes
2 answers
3k views

FFT vs DFT Run Time Comparison (Complexity Analysis) in MATLAB

So we were given an assignment to plot the time taken by the FFT algorithm by MATLAB and a DFT algorithm written by me in MATLAB.G The expected output should have been the DFT algorithm following the ...
Abhinav Jain's user avatar