ENEL 573 Lecture 1: CRC Error Detection
27 Sep 2018
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Document Summary
Most practical error detection schemes will have a few error patters that are not detected; the stronger the code, the more patterns are caught. The addition based checksums aren"t particularly strong since any error pattern that sums to zero will be missed. We can do better with error detection based on division: polynomial codes are a stronger form of error detection that uses division to generate a cyclical redundancy check (crc) Crc error detection is based on the division of bit sequences, not addition. This division makes use of binary finite field arithmetic. This field of math represents bit sequences using polynomials. The bits in a sequence are the coefficients of the polynomial. Addition, subtraction and multiplication are like normal algebra except with modulo 2. Addition example: (( " + ( + 1) + (( 1 + (, = ( 1 + ( " + 2( + 1 5672 ( 1 + ( " + 0( + 1.
