AFT Create FIR Filtered-X LMS VI

LabVIEW 2013 Adaptive Filter Toolkit Help

Edition Date: June 2013

Part Number: 372357B-01

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Owning Palette: Filtered-X Adaptive Filter VIs

Requires: Adaptive Filter Toolkit

Creates a finite impulse response (FIR) adaptive filter with the filtered-x least mean squares (LMS) algorithm.

Note  National Instruments recommends that you create and destroy adaptive filters outside loop structures.


secondary path specifies the impulse response of the secondary path. The length of the secondary path array must be greater than zero.
filter length specifies the filter length of the adaptive filter. The value must be greater than or equal to 2. The default is 128.
step size specifies the step size of the adaptive filter. The value must be greater than zero. A large step size can improve the convergence speed of the resulting adaptive filter. However, a large step size might result in a large steady state error or cause instability in the resulting adaptive filter. The default is 0.01.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
filtered-x adaptive filter out returns the filtered-x adaptive filter that this VI creates.
error out contains error information. This output provides standard error out functionality.


Refer to the following VIs for examples of using the AFT Create FIR Filtered-X LMS VI:

  • Active Noise Control (Simulated) VI: labview\examples\Adaptive Filters\Applications\Active Noise Control
  • Use Filtered-X LMS Adaptive Filter VI: labview\examples\Adaptive Filters\Getting Started


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