Computes the single-sided, scaled, auto power spectrum of a time-domain signal.


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Inputs/Outputs

  • c1ddbl.png Signal (V) —

    Signal specifies the input time-domain signal, usually in volts.

    The time-domain record must contain at least three cycles of the signal for a valid estimate.

  • cdbl.png dt —

    dt is the sample period of the time-domain signal, usually in seconds.

    Set dt to 1/fs, where fs is the sampling frequency of the time-domain signal. The default is 1.

  • i1ddbl.png Power Spectrum (V^2 rms) —

    Power Spectrum returns the single-sided power spectrum.

    If the input Signal is in volts (V), Power Spectrum has units of volts-rms squared (Vrms²). If the input Signal is not in volts, Power Spectrum has units of the input signal unit-rms squared.

  • idbl.png df —

    df is the frequency interval of the power spectrum in hertz, if dt is in seconds.

    • This VI computes the power spectrum using the following equation.

    where n is the number of points in the Signal and * denotes the complex conjugate. This VI then converts the power spectrum into a single-sided power spectrum.

    Related Information

    Output Units for FFT-Based VIs

    Examples

    Refer to the following example files included with LabVIEW.

    • labview\examples\Signal Processing\Transforms\FFT and Power Spectrum Units.vi