PhysicalCommunications.jl

Description

PhysicalCommunications.jl provides tools for the development & test of the physical communication layer (typically implemented in the "PHY" chip).

Eye Diagrams

• buildeye(): Builds an eye diagram by folding x values of provided (x,y) into multiple windows of teye that start (are "triggered") every tbit:
  • buildeye(x::Vector, y::Vector, tbit::Number, teye::Number; tstart::Number=0)

Example plotting with Plots.jl:

#Assumption: (x, y) data generated here.
tbit = 1e-9 #Assume data bit period is 1ns.

#Build eye & use tstart to center data.
eye = buildeye(x, y, tbit, 2.0*tbit, tstart=0.2*tbit)

plot(eye.vx, eye.vy)

Test Patterns

The PhysicalCommunications.jl module provides the means to create pseudo-random bit sequences to test/validate channel performance:

Example creation of PRBS pattern using maximum-length Linear-Feedback Shift Register (LFSR):

pattern = collect(sequence(MaxLFSR(31), seed=11, len=1000, output=Bool)).

Example validation of maximum-length LFSR sequence:

_errors = sequence_detecterrors(MaxLFSR(31), pattern)

Test Patterns: Supported Sequence Generators (Types)

• SequenceGenerator (abstract type): Defines algorithm used by sequence() to create a bit sequence.
• PRBSGenerator <: SequenceGenerator (abstract type): Specifically a pseudo-random bit sequence.
• MaxLFSR{LEN} <: PRBSGenerator: Identifies a "Maximum-Length LFSR" algorithm.
  • Reference: Alfke, Efficient Shift Registers, LFSR Counters, and Long Pseudo-Random Sequence Generators, Xilinx, XAPP 052, v1.1, 1996.
• **MaxLFSR_Iter{LEN,TRESULT}: "Iterator" object for MaxLFSR sequence generator.
  • Must collect(::MaxLFSR_Iter) to obtain sequence values.

Test Patterns: Iterable API

• sequence(): Create an iterable object that defines a bit sequence of length len..
  • sequence(t::SequenceGenerator; seed::Integer=11, len::Int=-1, output::DataType=Int)
  • Must use collect(sequence([...])) to obtain actual sequence values.

Compatibility

Extensive compatibility testing of PhysicalCommunications.jl has not been performed. The module has been tested using the following environment(s):

• Linux / Julia-1.1.1

Disclaimer

The PhysicalCommunications.jl module is not yet mature. Expect significant changes.