Sunday, June 21, 2020

LFSR - linear feedback shift register


LFSR - linear feedback shift register
& fast algorithm ???

Every primitive polynomial will have an odd number of terms, which means that every mask for a primitive polynomial will have an even number of 1 bit. Every primitive polynomial also defines a second primitive polynomial, its dual. The dual can be found by subtracting the exponent from the degree of the polynomial for each term. For example, given the 6th-degree polynomial, x6 + x + 1, its dual is x6-6 + x6-1 + x6-0, which is equal to x6 + x5 + 1. In Table 1, polynomials 1 and 2, 3 and 4, 5 and 6 are the duals of each other.

http://www.johnkerl.org/doc/ffcomp.pdf
LFSRs.pdf
LFSR-notes.PDF


* reference
http://www.cs.fsu.edu/~xyuan/cda5125/347603_347603.pdf

Syndrome decode

Syndrome decoding in Wikipedia
Syndrome decoding in UCSD pdf (An introduction to error correcting codes part 1)