M-sequences in Julia?

KajWiik · February 13, 2022, 10:30am

Is there a package for generating m-sequences (Maximum length sequence - Wikipedia) in Julia? At least with a quick search I did not find anything.

KajWiik · February 13, 2022, 10:41am

And as always, a couple of minutes after asking you find it yourself :

github.com

JuliaTelecom/PhysicalCommunications.jl/blob/master/src/prbs.jl

#PhysicalCommunications: Pseudo-Random Bit Sequence Generators/Checkers
#-------------------------------------------------------------------------------


#==Constants
===============================================================================#

#Integer representation of polynomial x^p1 + x^p2 + x^p3 + x^p4 + 1
_poly(p1::Int) = one(UInt64)<<(p1-1)
_poly(p1::Int, p2::Int) = _poly(p1) + _poly(p2)
_poly(p1::Int, p2::Int, p3::Int, p4::Int) = _poly(p1) + _poly(p2) + _poly(p3) + _poly(p4)

#==Maximum-length Linear-Feedback Shift Register (LFSR) polynomials/taps (XNOR form)
Ref: Alfke, Efficient Shift Registers, LFSR Counters, and Long Pseudo-Random
     Sequence Generators, Xilinx, XAPP 052, v1.1, 1996.==#
const MAXLFSR_POLYNOMIAL = [
	_poly(64,64) #1: not supported
	_poly(64,64) #2: not supported
	_poly(3,2) #3
	_poly(4,3) #4

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ssfrr · February 13, 2022, 1:19pm

A couple years ago I also wrote this package with tools for measuring impulse responses, including with MLS:

It’s not maintained or published, but feel free to grab code if you want to.

KajWiik · February 13, 2022, 1:25pm

In fact this is exactly what I need, many thanks for sharing!