Re:Linear Feedback Shift Registers
by kurthr on Monday November 20, 2017 @03:11AM
(#15738532)
LFSRs are an interesting topic since they see so much use in hardware testing, scrambling, and orthogonal coding. Typically they are used as MLS-Maximum Length Sequences. These sequences and the generating polynomials were (I think?) shown to be related groups by Galois. Look for Golomb and Rice coding if you're interested in this math.
It's a bit odd that they only show the Galois generation method in this blog and not the more commonly used Fibonacci feedback method which takes the current state and generate the next bit each clock (rather than modifying multiple bits each shift).
Note that Gold and Kasami codes are related to MLS... and if you recognize those names from NASA, it's because they developed those high auto-correlation codes for GPS and interplanetary communication.
https://en.wikipedia.org/wiki/Maximum_length_sequence
It's a bit odd that they only show the Galois generation method in this blog and not the more commonly used Fibonacci feedback method which takes the current state and generate the next bit each clock (rather than modifying multiple bits each shift).
Note that Gold and Kasami codes are related to MLS... and if you recognize those names from NASA, it's because they developed those high auto-correlation codes for GPS and interplanetary communication.