The signlms function creates an adaptive
algorithm object that you can use with the lineareq function
or dfe function to create an
equalizer object. You can then use the equalizer object with the equalize function to equalize a signal.
To learn more about the process for equalizing a signal, see Adaptive Algorithms.

alg = signlms(stepsize) constructs
an adaptive algorithm object based on the signed least mean square
(LMS) algorithm with a step size of stepsize.

alg = signlms(stepsize,algtype) constructs
an adaptive algorithm object of type algtype from
the family of signed LMS algorithms. The table below lists the possible
values of algtype.

Value
of algtype

Type of Signed LMS Algorithm

'Sign LMS'

Sign LMS (default)

'Signed Regressor
LMS'

Signed regressor LMS

'Sign Sign LMS'

Sign-sign LMS

Properties

The table below describes the properties of the signed LMS adaptive
algorithm object. To learn how to view or change the values of an
adaptive algorithm object, see Access Properties of an Adaptive Algorithm.

Property

Description

AlgType

Type of signed LMS algorithm,
corresponding to the algtype input argument.
You cannot change the value of this property after creating the object.

StepSize

LMS step size parameter,
a nonnegative real number

LeakageFactor

LMS leakage factor, a real
number between 0 and 1. A value of 1 corresponds to a conventional
weight update algorithm, while a value of 0 corresponds to a memoryless
update algorithm.

Referring to the schematics presented in Equalizer Structure, define w as
the vector of all weights w_{i} and
define u as the vector of all inputs u_{i}.
Based on the current set of weights, w, this adaptive
algorithm creates the new set of weights given by

(LeakageFactor) w + (StepSize) u^{*}sgn(Re(e)),
for sign LMS

(LeakageFactor) w + (StepSize) sgn(Re(u))
Re(e), for signed regressor LMS

(LeakageFactor) w + (StepSize) sgn(Re(u))
sgn(Re(e)), for sign-sign LMS

where the * operator denotes the complex
conjugate and sgn denotes the signum function (sign in MATLAB^{®} technical
computing software).