Computes the single-sided time-cepstrum of a univariate time series by using a sliding window. You can use the resulting time-cepstrum to detect time-varying periodic components of a time series. Wire data to the Xt input to determine the polymorphic instance to use or manually select the instance.


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Inputs/Outputs

  • cu16.png method —

    method specifies whether this VI uses the FFT-based or the autoregressive (AR) model-based method to compute the real cepstrum. The default is FFT.

  • cdbl.png quefrency offset —

    quefrency offset specifies the offset, in seconds, of the quefrency. This VI returns the real cepstrum at a certain time whose quefrency is larger than the offset value. The default is 0.

  • c1ddbl.png Xt —

    Xt specifies the univariate time series.

  • cnclst.png time-quefrency sampling info —

    time-quefrency sampling info specifies information about the density and the size of the time-cepstrum.

  • ci32.png time steps —

    time steps specifies the sampling period, in number of samples, along the time axis in the joint time-quefrency domain. The default is -1, which specifies that this VI adjusts time steps automatically so that no more than 512 rows exist in the cepstrogram.

  • ci32.png quefrency bins —

    quefrency bins specifies the number of bins along the quefrency axis of the cepstrogram to sample the time series in the joint time-quefrency domain. quefrency bins must be greater than 0. The scale info output contains the actual sampling period, in seconds, along the quefrency axis of the cepstrogram. The default is 512.

  • cnclst.png window info —

    window info specifies the information about the sliding window that divides the time series Xt into subsequences.

  • ci32.png type —

    type specifies the time-domain window that this VI applies to the time series.

  • ci32.png length —

    length specifies the length of the window in samples. The default is -1, which indicates that the window length equals the length of the input time series.

  • cerrcodeclst.png error in (no error) —

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

  • cnclst.png AR setting —

    AR setting specifies the settings for the autoregressive (AR) model. This option is valid only when the method is AR Model.

  • cu16.png AR method —

    AR method specifies the method this VI uses to estimate the autoregressive (AR) model.

  • ci32.png AR order —

    AR order specifies the order of the autoregressive (AR) model. The value of AR order must be greater than 0. The default is 4.

  • cdbl.png sampling rate —

    sampling rate specifies the sampling rate, in hertz, of the univariate time series Xt. The default is 1.

  • i2ddbl.png cepstrogram —

    cepstrogram returns the time-quefrency representation of the time series Xt. Each row corresponds to the real cepstrum at a certain time. The number of rows in cepstrogram equals the signal length divided by time steps.

  • ifxdt.png scale info —

    scale info returns the time scale and quefrency scale information of the time-quefrency representation, including the time offset, the time interval between every two contiguous rows, the quefrency offset, and the quefrency interval between every two contiguous columns of the cepstrogram.

  • idbl.png overlap —

    overlap returns the overlap, in percentage, of the sliding window this VI applies to the time series.

  • ierrcodeclst.png error out —

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

    • Examples

    Refer to the Bearing Time-Cepstrum Analysis VI in the labview\examples\Time Series Analysis\TSAApplications directory for an example of using the TSA Time-Cepstrum VI.