Communications Toolbox

Specifying an Adaptive Equalizer

As mentioned earlier in Basic Procedure for Equalizing a Signal, you must create an equalizer object before you can equalize a signal. This section describes how to define an equalizer object and how to access its properties.

Defining an Equalizer Object

To create an equalizer object, use one of the functions listed in the table below.

For example, the code below creates three equalizer objects: one representing a symbol-spaced linear RLS equalizer having 10 weights, one representing a fractionally spaced linear RLS equalizer having 10 weights and two samples per symbol, and one representing a decision-feedback RLS equalizer having 3 weights in the feedforward filter and 2 weights in the feedback filter.

% Create equalizer objects of different types.
eqlin = lineareq(10,rls(0.3)); % Symbol-spaced linear
eqfrac = lineareq(10,rls(0.3),[-1 1],2); % Fractionally spaced linear
eqdfe = dfe(3,2,rls(0.3)); % DFE

Although the lineareq and dfe functions have different syntaxes, they both require an input argument that represents an adaptive algorithm. To learn how to represent an adaptive algorithm or how to vary properties of the adaptive algorithm, see Specifying an Adaptive Algorithm.

Each of the equalizer objects created above is a valid input argument for the equalize function. To learn how to use the equalize function to equalize a signal, see Using Adaptive Equalizers.

Duplicating and Copying Objects

Another way to create an object is to duplicate an existing object and then adjust the properties of the new object, if necessary. If you do this, it is important that you use a copy command such as

c2 = copy(c1); % Copy c1 to create an independent c2.

instead of c2 = c1. The copy command creates a copy of c1 that is independent of c1. By contrast, the command c2 = c1 creates c2 as merely a reference to c1, so that c1 and c2 always have indistinguishable content.

Accessing Properties of an Adaptive Algorithm

Accessing Properties of an Equalizer

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