Performs time-varying filtering on a signal. Wire data to the signal input to determine the polymorphic instance to use or manually select the instance.

Note This VI does not support the LabVIEW Real-Time Module.

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


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Inputs/Outputs

  • c1dcdb.png signal —

    signal specifies the input signal.

  • cnclst.png threshold settings —

    threshold settings specifies the parameters to process the Gabor coefficients. You can change the front panel values of threshold settings.

  • cdbl.png threshold —

    threshold specifies the amplitude of the threshold for the Gabor coefficients.

  • cdbl.png noise level —

    noise level removes the small particles in the joint time-frequency representation plot. The functionality to remove small particles requires NI Vision. If you do not have NI Vision installed, this VI ignores this input.

  • cerrcodeclst.png error in (no error) —

    error in describes error conditions that occur before this node runs. This input provides standard error in functionality.

  • cbool.png open front panel? (T) —

    open front panel? specifies to display the Time Varying Filter dialog box, where you can set the parameters for the time-varying filter and see the results. If open front panel? is FALSE, this VI uses threshold settings to generate the specification for the time-varying filter. The default is TRUE, which means this VI displays the Time Varying Filter dialog box so you can set the parameters for the time-varying filter and see the results.

  • i1dcdb.png filtered signal —

    filtered signal returns the filtered signal.

  • inclst.png threshold settings out —

    threshold settings out returns the actual parameters to threshold the Gabor coefficients in this VI.

  • idbl.png threshold —

    threshold returns the actual threshold.

  • idbl.png noise level —

    noise level returns the actual noise level.

  • ierrcodeclst.png error out —

    error out contains error information. This output provides standard error out functionality.

    • TFA Time Varying Filter Details

    The time-varying filter is suitable for transient signals whose frequency evolves over time. This VI converts the time-domain signal to the joint time-frequency domain with the Gabor transform, removes noise in the joint time-frequency domain, and then reconstructs the time-domain signal with the Gabor expansion by using the Gabor coefficients after thresholding.

    Examples

    Refer to the Time Varying Filter VI in the labview\examples\Time Frequency Analysis\TFAFunctions directory for an example of using the TFA Time Varying Filter VI.