ni5660 Read Averaged Power Spectrum

NI PXI-5660

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ni5660 Read Averaged Power Spectrum

This VI computes the averaged power spectrum that corresponds to the spectral settings specified in the ni5660 Configure for Spectrum VI. The VI returns a cluster that contains the averaged power spectrum in V2rms, starting at frequency f0 and frequency interval df. You can perform RMS averaging with linear, exponential, or peak-hold weighting.

receiver info in is the instrument handle that you obtain from the ni5660 Initialize VI. The handle identifies a particular RF Signal Analyzer session.
number of averages specifies either the number of averages to complete for linear weighting, or the time constant for exponential weighting. The VI stops the averaging process and returns the final result after number of averages is complete.
Default Value: 10 averages
averaging weighting type specifies the type of weighting used by the VI:
  • Linear weighting specifies that each measurement has equal weighting during the averaging process.
  • Exponential weighting specifies that each new measurement has less weighting than old measurements and that the averaging is continuous. The averaging process computes the exponentially weighted average for measurement i as
      Avg [i] = 1/N * X + (N - 1)/N * Avg[i - 1]

    where X is the new measurement, Avg[i - 1] is the previous average and N is the number of averages.
  • Peak hold weighting specifies that the VI calculates and retains the maximum rms levels for each frequency bin across FFT records. The peak rms value for each bin is returned.
Default Value: linear
correction factor specifies the array of correction factors previously computed by the ni5660 Configure for Spectrum VI. Wire the correction factor output of the ni5660 Configure for Spectrum VI directly to this input. Do not modify the values.
error in accepts error information wired from previously called VIs.

The pop-up option Explain Error (or Explain Warning) gives more information about the error displayed.

status boolean is either TRUE (X) for an error, or FALSE (checkmark) for no error or a warning. The pop-up option Explain Error (or Explain Warning) gives more information about the error displayed.
code input identifies the error or warning. The pop-up option Explain Error (or Explain Warning) gives more information about the error displayed.
source string describes the origin of the error or warning. The pop-up option Explain Error (or Explain Warning) gives more information about the error displayed.
receiver info out passes a reference to your instrument session to the next VI. receiver info was obtained from the ni5660 Initialize VI.
Note  Do not modify the contents of this wire manually.
averaged power spectrum returns the averaged power spectrum in V2rms scaling, starting at frequency f0 with frequency interval df.
f0 returns the start frequency of the spectrum, expressed in Hz.
df returns the frequency interval between data points in the spectrum, expressed in Hz.
spectrum returns the averaged power spectrum.
spectral info out returns properties of the computed spectrum such as spectrum type, spectrum scale (linear or dB), the window type used by the VI to compute the spectrum, window size, and FFT size. Connect this parameter to subsequent VIs that contain the spectral info input parameter. Do not modify the values.
error out passes error or warning information out of a VI to be used by other VIs. The pop-up option Explain Error (or Explain Warning) gives more information about the error displayed.
status is TRUE (X) if an error occurred, or FALSE (checkmark) for no error or a warning. The pop-up option Explain Error (or Explain Warning) gives more information about the error displayed.
code identifies the error or warning. The pop-up option Explain Error (or Explain Warning) gives more information about the error displayed.
source describes the origin of the error or warning. The pop-up option Explain Error (or Explain Warning) gives more information about the error displayed.
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