Note: This page has been translated by MathWorks. Click here to see

To view all translated materials including this page, select Country from the country navigator on the bottom of this page.

To view all translated materials including this page, select Country from the country navigator on the bottom of this page.

Adaptive lattice filter

The `dsp.AdaptiveLatticeFilter`

System
object™ computes output, error, and coefficients using a lattice-based FIR adaptive
filter.

To implement the adaptive FIR filter object:

Create the

`dsp.AdaptiveLatticeFilter`

object and set its properties.Call the object with arguments, as if it were a function.

To learn more about how System objects work, see What Are System Objects? (MATLAB).

`alf = dsp.AdaptiveLatticeFilter`

`alf = dsp.AdaptiveLatticeFilter(len)`

`alf = dsp.AdaptiveLatticeFilter(Name,Value)`

returns a
lattice-based FIR adaptive filter System
object, `alf`

= dsp.AdaptiveLatticeFilter`alf`

. This System
object computes the filtered output and the filter error for a given input and
desired signal.

returns an `alf`

= dsp.AdaptiveLatticeFilter(`len`

)`AdaptiveLatticeFilter`

System
object with the `Length`

property set to
`len`

.

returns an `alf`

= dsp.AdaptiveLatticeFilter(`Name,Value`

)`AdaptiveLatticeFilter`

System
object with each specified property set to the specified value. Enclose each
property name in single quotes. Unspecified properties have default values.

**For versions earlier than R2016b, use the step
function to run the System object algorithm. The arguments to
step are the object you created, followed by
the arguments shown in this section.**

**For example, y = step(obj,x) and y = obj(x) perform equivalent operations.**

`[y,err] = alf(x,d)`

`[`

filters the input `y`

,`err`

] = alf(`x`

,`d`

)`x`

, using `d`

as the desired
signal, and returns the filtered output in `y`

and the filter error in
`err`

. The System object estimates the filter weights needed to minimize the error
between the output signal and the desired signal. You can access these coefficients by
accessing the `Coefficients`

property of the object. This can be done
only after calling the object. For example, to access the optimized coefficients of the
`alf`

filter, call `alf.Coefficients`

after you pass
the input and desired signal to the object.

To use an object function, specify the
System
object as the first input argument. For
example, to release system resources of a System
object named `obj`

, use
this syntax:

release(obj)

[1] Griffiths, Lloyd J. “A Continuously
Adaptive Filter Implemented as a Lattice Structure”. *Proceedings
of IEEE Int. Conf. on Acoustics, Speech, and Signal Processing,* Hartford,
CT, pp. 683–686, 1977 .

[2] Haykin, S. *Adaptive Filter
Theory*, 4th Ed. Upper Saddle River, NJ: Prentice Hall,
1996.