Filter Design Toolbox

Algorithms

For adaptive filter (adaptfilt) objects, the algorithm string determines which adaptive filter algorithm your adaptfilt object implements. Each available algorithm entry appears in one of the tables along with a brief description of the algorithm. Click on the algorithm in the first column to get more information about the associated adaptive filter technique.

• LMS based adaptive filters
• RLS based adaptive filters
• Affine projection adaptive filters
• Adaptive filters in the frequency domain
• Lattice based adaptive filters
• Subband adaptive filter

Least Mean Squares (LMS) Based FIR Adaptive Filters

adaptfilt.algorithm String	Description of the Adapting Algorithm Used to Generate Filter Coefficients During Adaptation
adaptfilt.adjlms	Use the Adjoint LMS FIR adaptive filter algorithm
adaptfilt.blms	Use the Block LMS FIR adaptive filter algorithm
adaptfilt.blmsfft	Use the the FFT-based Block LMS FIR adaptive filter algorithm
adaptfilt.dlms	Use the delayed LMS FIR adaptive filter algorithm
adaptfilt.filtxlms	Use the filtered-x LMS FIR adaptive filter algorithm
adaptfilt.lms	Use the LMS FIR adaptive filter algorithm
adaptfilt.nlms	Use the normalized LMS FIR adaptive filter algorithm
adaptfilt.sd	Use the sign-data LMS FIR adaptive filter algorithm
adaptfilt.se	Use the sign-error LMS FIR adaptive filter algorithm
adaptfilt.ss	Use the sign-sign LMS FIR adaptive filter algorithm

For further information about an adapting algorithm, refer to the reference page for the algorithm.

Recursive Least Squares (RLS) Based FIR Adaptive Filters

adaptfilt.algorithm String	Description of the Adapting Algorithm Used to Generate Filter Coefficients During Adaptation
adaptfilt.ftf	Use the fast transversal least-squares adaptation algorithm
adaptfilt.qrdrls	Use the QR-decomposition RLS adaptation algorithm
adaptfilt.hrls	Use the householder RLS adaptation algorithm
adaptfilt.hswrls	Use the householder SWRLS adaptation algorithm
adaptfilt.rls	Use the recursive-least squares (RLS) adaptation algorithm
adaptfilt.swrls	Use the sliding window (SW) RLS adaptation algorithm
adaptfilt.swftf	Use the sliding window ftf adaptation algorithm

For more complete information about an adapting algorithm, refer to the reference page for the algorithm.

Affine Projection (AP) FIR Adaptive Filters

adaptfilt.algorithm String	Description of the Adapting Algorithm Used to Generate Filter Coefficients During Adaptation
adaptfilt.ap	Use the affine projection algorithm that uses direct matrix inversion
adaptfilt.apru	Use the affine projection algorithm that uses recursive matrix updating
adaptfilt.bap	Use the block affine projection adaptation algorithm

To find more information about an adapting algorithm, refer to the reference page for the algorithm.

FIR Adaptive Filters in the Frequency Domain (FD)

adaptfilt.algorithm String	Description of the Adapting Algorithm Used to Generate Filter Coefficients During Adaptation
adaptfilt.fdaf	Use the frequency domain adaptation algorithm
adaptfilt.pbfdaf	Use the partition block version of the fdaf algorithm
adaptfilt.pbufdaf	Use the partion block unconstrained version of the fdaf algorithm
adaptfilt.tdafdct	Use the transform domain adaptation algorithm using DCT
adaptfilt.tdafdft	Use the transform domain adaptation algorithm using DFT
adaptfilt.ufdaf	Use the unconstrained fdaf algorithm for adaptation

For more information about an adapting algorithm, refer to the reference page for the algorithm.

Lattice Based (L) FIR Adaptive Filters

adaptfilt.algorithm String	Description of the Adapting Algorithm Used to Generate Filter Coefficients During Adaptation
adaptfilt.gal	Use the gradient adaptive lattice filter adaptation algorithm
adaptfilt.lsl	Use the least squares lattive adaptation algorithm
adaptfilt.qrdlsl	Use the QR decomposition RLS adaptation algorithm

For more information about an adapting algorithm, refer to the reference page for the algorithm.

Presenting a detailed derivation of the Wiener-Hopf equation and determining solutions to it is beyond the scope of this User's Guide. Full descriptions of the theory appear in the adaptive filter references provided in the Selected Bibliography.

Using Adaptive Filter Objects

After you construct and adaptive filter object, how do you apply it to to your data or system? Like quantizer objects, adaptive filter objects have a filter method that you use to apply the adaptfilt object to data. In the following sections, various examples of using LMS and RLS adaptive filters show you how filter works with the objects to apply them to data.

• Examples of Adaptive Filters That Use LMS Algorithms
• Example of Adaptive Filter That Uses RLS Algorithm

Adaptive Filters in the Filter Design Toolbox

Examples of Adaptive Filters That Use LMS Algorithms