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AFT Create FIR LMS VI

LabVIEW 2013 Adaptive Filter Toolkit Help

Edition Date: June 2013

Part Number: 372357B-01

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Owning Palette: Adaptive Filters VIs

Requires: Adaptive Filter Toolkit

Creates a finite impulse response (FIR) adaptive filter with the standard least mean squares (LMS) algorithm. If you specify a nonzero value for the leakage input, this VI creates an FIR adaptive filter with the leaky LMS algorithm. You must manually select the polymorphic instance you want to use.

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

Examples

Use the pull-down menu to select an instance of this VI.

AFT Create FIR LMS (Real)

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. Use the AFT Estimate Maximum Step Size for FIR LMS VI to estimate the maximum step size value. The default is 0.01.
leakage specifies the leaky factor of the adaptive filter. The valid value range is [0, 0.1]. If the value is zero, this VI uses the standard LMS algorithm to create the adaptive filter. If the value is nonzero, this VI uses the leaky LMS algorithm to create the adaptive filter. The default is 0.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
adaptive filter out returns the adaptive filter that this VI creates.
error out contains error information. This output provides standard error out functionality.

AFT Create FIR LMS (Complex)

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. Use the AFT Estimate Maximum Step Size for FIR LMS VI to estimate the maximum step size value. The default is 0.01.
leakage specifies the leaky factor of the adaptive filter. The valid value range is [0, 0.1]. If the value is zero, this VI uses the standard LMS algorithm to create the adaptive filter. If the value is nonzero, this VI uses the leaky LMS algorithm to create the adaptive filter. The default is 0.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
adaptive filter out returns the adaptive filter that this VI creates.
error out contains error information. This output provides standard error out functionality.

Examples

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

  • Convergence Speed and Computation Time of Adaptive Filters VI: labview\examples\Adaptive Filters\Getting Started
  • Fetal ECG Signal Extraction VI: labview\examples\Adaptive Filters\Applications\Fetal ECG Signal Extraction

 

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