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AFT Create FIR Normalized 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 normalized least mean squares (NLMS) algorithm. If you specify a nonzero value for the leakage input, this VI creates an FIR adaptive filter with the normalized 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 Normalized 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 and less than 2. The default is 0.1. 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 adaptive filter becomes unstable if the step size value is greater than 2.
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 normalized LMS algorithm to create the adaptive filter. If the value is nonzero, this VI uses the normalized 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 Normalized 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 and less than 2. The default is 0.1. 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 adaptive filter becomes unstable if the step size value is greater than 2.
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 normalized LMS algorithm to create the adaptive filter. If the value is nonzero, this VI uses the normalized 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 Normalized LMS VI:

  • Use Adaptive Filter for Linear Prediction VI: labview\examples\Adaptive Filters\Getting Started
  • Online Order Waveform Extraction (DAQmx) VI: labview\examples\Adaptive Filters\Applications\Online Order Waveform Extraction

 

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