Cross Spectrum (Real-Im) VI

Computes the averaged cross power spectrum of the input signals. Results are returned as real and imaginary parts.


icon

Inputs/Outputs

  • cdbl.png window parameter —

    window parameter specifies the beta parameter for a Kaiser window, the standard deviation for a Gaussian window, and the ratio, s, of the main lobe to the side lobe for a Dolph-Chebyshev window. If window is any other window, this VI ignores this input.

    The default value of window parameter is NaN, which sets beta to 0 for a Kaiser window, the standard deviation to 0.2 for a Gaussian window, and s to 60 for a Dolph-Chebyshev window.

  • cbool.png restart averaging (F) —

    restart averaging specifies whether the VI restarts the selected averaging process. If restart averaging is TRUE, the VI restarts the selected averaging process. If restart averaging is FALSE, the VI does not restart the selected averaging process. The default is FALSE.

    When you call this VI for the first time, the averaging process restarts automatically. A typical case when you should restart averaging is when a major input change occurs in the middle of the averaging process.

  • cmsdt.png time signal X —

    time signal X is the time waveform X.

  • cmsdt.png time signal Y —

    time signal Y is the time waveform Y.

  • cu32.png window —

    window (Hanning) is the time-domain window to apply to the time signal. The default window is Hanning.

    0Rectangle
    1Hanning (default)
    2Hamming
    3Blackman-Harris
    4Exact Blackman
    5Blackman
    6Flat Top
    74 Term B-Harris
    87 Term B-Harris
    9Low Sidelobe
    11Blackman Nutall
    30Triangle
    31Bartlett-Hanning
    32Bohman
    33Parzen
    34Welch
    60Kaiser
    61Dolph-Chebyshev
    62Gaussian
  • 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 averaging parameters —

    averaging parameters defines how the averaging is computed. The specifications of the parameters include the type of averaging, the type of weighting, and the number of averages.

  • cenum.png averaging mode —

    averaging mode specifies the averaging mode.

    0
    No averaging
    (default)
    1
    Vector averaging
    2
    RMS averaging
    3
    Peak hold
  • cenum.png weighting mode —

    weighting mode specifies the weighting mode for RMS and vector averaging.

    0
    Linear
    1
    Exponential
    (default)
  • cu32.png number of averages —

    number of averages specifies the number of averages used for RMS and vector averaging. If weighting mode is exponential, the averaging process is continuous. If weighting mode is linear, the averaging process stops after this VI computes the selected number of averages.

  • ibool.png averaging done —

    averaging done returns TRUE when averages completed is greater than or equal to the number of averages specified in averaging parameters. Otherwise, averaging done returns FALSE. averaging done is always TRUE if the selected averaging mode is No averaging.

  • icclst.png real part —

    real part returns the real part of the averaged cross power spectrum and the frequency scale.

  • idbl.png f0 —

    f0 returns the start frequency, in hertz, of the spectrum.

  • idbl.png df —

    df returns the frequency resolution, in hertz, of the spectrum.

  • i1ddbl.png real part —

    real part is the real part of the averaged cross power spectrum.

  • icclst.png imaginary part —

    imaginary part returns the imaginary part of the averaged cross power spectrum and the frequency scale.

  • idbl.png f0 —

    f0 returns the start frequency, in hertz, of the spectrum.

  • idbl.png df —

    df returns the frequency resolution, in hertz, of the spectrum.

  • i1ddbl.png imaginary part —

    imaginary part is the imaginary part of the averaged cross power spectrum.

  • idbl.png averages completed —

    averages completed returns the number of averages completed by the VI at that time.

  • ierrcodeclst.png error out —

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

    • Typically, time signal X is the stimulus, and time signal Y is the response of the system. Each time waveform corresponds to a single FFT block. You have to pass each time waveform individually to this VI.