Uses the complex-valued Morlet wavelet to compute the continuous wavelet transform (CWT) of a 1D input signal. Wire data to the signal input to determine the polymorphic instance to use or manually select the instance.


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Inputs/Outputs

  • cu16.png normalization —

    normalization specifies how to scale the dilated wavelets.

  • ci32.png time steps —

    time steps specifies the number of samples to translate, or shift, the wavelet in the analytic wavelet transform (AWT). The default is -1, which specifies that this VI adjusts time steps automatically so that no more than 512 coefficients exist at each scale.

  • cmsdt.png signal —

    signal specifies the input signal.

  • ci32.png scales —

    scales specifies the number of scales of the dilated wavelet.

  • cu16.png scale sampling method —

    scale sampling method specifies the method to use to select the scales of the wavelets. scale sampling method affects the mapping style of the y-axis of the scalogram. Use the user defined scales input to specify a customized scale.

  • cerrcodeclst.png error in (no error) —

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

  • c1ddbl.png user defined scales —

    user defined scales specifies the scales to use to compute AWT coef. The scale must be positive and no greater than the length of signal. If you specify a value for user defined scales, this VI ignores the settings in the scale sampling method input and the scales input.

  • i2dcdb.png AWT coef —

    AWT coef returns the results of the analytic wavelet transform (AWT).

  • ifxdt.png scale info —

    scale info returns the time information and the scale (frequency) information, which this VI uses in the scalogram plot.

  • ierrcodeclst.png error out —

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

    • WA Analytic Wavelet Transform Details

    The AWT is a special case of the CWT with the complex-valued Morlet wavelet, also called the Gabor wavelet. The following equation defines the complex-valued Morlet wavelet:

    where is the standard deviation of the Gaussian envelope of the mother wavelet, and is the central frequency of the mother wavelet, which is in this VI.

    Examples

    Refer to the following VIs for examples of using the WA Analytic Wavelet Transform VI:

    • Scalogram with Analytic Wavelet Transform VI: labview\examples\Wavelet Analysis\WAGettingStarted
    • Spectrogram Ridge Detection VI: labview\examples\Wavelet Analysis\WAGettingStarted
    • Color Tables for Displaying the Scalogram VI: labview\examples\Wavelet Analysis\WAGettingStarted