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Questions tagged [crc]

Cyclic redundancy check. An error checking mechanism used for verifying data integrity in serial protocols.

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What is the hamming distance, and how do I determine it for a CRC scheme?

While studying for a class in computer networks, the prof talked about the hamming distance between 2 valid code words in a sample code. I have read about hamming distance, and it makes sense from the perspective of telling the difference distance…
naivedeveloper
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A few questions about CRC basics

I am an electronic engineer and have not found it important to consider CRC from a purely mathematical perspective. However, I have the following questions: Why do we add n zeros to the message when we calculate the CRC, were n is the degree of the…
quantum231
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Expected collisions for perfect 32bit crc

I'm trying to determine how my crc compares to an "ideal" 32bit crc. So I ran my crc over 1 million completely random samples of data and collected the amount of collisions, I want to compare this number to the number of collisions I could expect…
Tristan
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Python - eyeD3 Lame tag CRC check failed

I am trying to write a script to clean up mp3 file names using Python and eyeD3 but I am getting "WARNING:eyed3.mp3.headers:Lame tag CRC check failed" when I try to load an mp3 file using the following script import string import os import…
Jay Bell
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CRC checks for files

I'm working with a small FAT16 filesystem, and I want to generate CRC values for indidual XML files which store configuration information. In case the data changes or is corrupted, I want to be able to check the CRC to determine that the file is…
Danny
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Convert C CRC16 to Java CRC16

I am currently working on a project, having an embedded system sending data to a PC via radio. The packets get a crc16 checksum at the end and it's calculated based on this algorithm: uint16_t crc16 (const uint8_t * buffer, uint32_t size) { …
tellob
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Python CRC8 calculation

I have some bytes I want to calculate the CRC8 on in python. I don't have such an experience with that but I know, from the tech specs of my device, that this calculation has to be made with a 0x07 polynom, and a 0x00 initialization. Let's take an…
orestino
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Does the UDP protocol have some error detection?

The User Datagram Protocol provides some error detection. Someone says that it has checksum mechanics. But this protocol does not have a hand shaking process. So this protocol does not seem to worry about the data errors. How can it have a…
Manjitha Teshara
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Library for CRC16 checksum in Elixir

I need to calculate CRC 16 of a string in elixir. Is there an existing library for the purpose?
Kshitij Mittal
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Modbus Communication

I am using C# to communicate via modbus rs485 rs232 to 2 phase meters that among other log the power voltage. I have to send data over the bus so that i can receive the readings. I have connected a normal wire and shorted the send and receive. The…
Combinu
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How to calculate CRC 16 with polynomial x16 + x12 + x5 + 1

I am trying to interface with some system and in their specs they require to calculate CRC 16 for serial communication. Here is an extract from documentation "16 bit CCITT CRC of the message utilizing the standard polynomial, X16 +X12 +X5 +1. Seed…
fenix2222
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Why is the Frame Check Sequence at the end of an Ethernet frame and not somewhere else

An Ethernet Frame Check Sequence is always appended to the end of a frame in the Data Link Layer. Why is it appended to the end of the frame and not somewhere else? I thought about it and think it might have something to do with how e.g.…
Lukas_Skywalker
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XAPK File validation shows in correct data Information

While running APK expansion file sample I just skiped checking CRC32 to avoide crc bug algorithm and its working very fine!! But while XAPK File validation shows in correct downloaded data information 99% !!, how to avoid that and view full 100% by…
LOG_TAG
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What is a running CRC?

I have searched and am not able to find information on what it is and how it is computed. I have no idea why the question has been negative voted. Is it not clear and programming related? Or should I have asked: # Or you can compute the running…
Alan Haggai Alavi
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CRC-32 implementation in java.util.zip.CRC32

Which CRC-32 algorithm is used in the Java CRC-32 class ? The java doc does not give any details. What is the polynomail used and the initial value for calculaton ?
Dunxton
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