SVFA Power Spectral Density Subset VI
- Updated2025-12-02
- 10 minute(s) read
Owning Palette: Baseband Subset VIs
Requires: Sound and Vibration Toolkit
Computes a subset of the power spectral density of scaled signal [EU] . The subset is defined by frequency range . Each block of data corresponds to a single FFT block and has to be passed individually to this VI. Wire data to the scaled signal [EU] input to determine the polymorphic instance to use or manually select the instance.
| SVFA Power Spectral Density Subset (1 Ch)SVFA Power Spectral Density Subset (N Ch) |
SVFA Power Spectral Density Subset (1 Ch)
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desired units
specifies if the results are expressed in EU^2/Hz or EU/sqrt(Hz).
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scaled signal [EU]
specifies the scaled signal expressed in the selected engineering units. To obtain a properly scaled signal, you can use the SVL Scale Voltage to EU VI or define a virtual channel in National Instruments Measurement & Automation Explorer (MAX).
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window
specifies the time-domain window used. The default is Hanning.
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frequency range
specifies the frequency band of analysis. The valid range for the start frequency and for the stop frequency is between 0 and the Nyquist frequency.
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dB On specifies whether the results are expressed in decibels. The default is FALSE. | ||||||||||||||||||||||||||||||||||||||
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error in describes error conditions that occur before this node runs. This input provides standard error in functionality. | ||||||||||||||||||||||||||||||||||||||
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averaging parameters
specifies how the VI computes the averaging. The specifications of the parameters include the type of averaging, the type of weighting, and the number of averages.
Note
When you set
averaging mode
to
No averaging
, the VI ignores the
weighting mode
,
number of averages
, and
linear mode
settings.
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restart averaging specifies if the selected averaging process has to be restarted. The default is FALSE. When you call this VI for the first time, the averaging process restarts automatically. | ||||||||||||||||||||||||||||||||||||||
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power spectral density [EU^2 rms / Hz]
returns the power spectral density.
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unit label returns the selected engineering units. | ||||||||||||||||||||||||||||||||||||||
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spectrum info
returns information about the spectrum needed by the Spectrum Extended Measurements VIs, the Display VIs, and the Tone and Distortion VIs.
Note
You must wire
spectrum info
when performing extended measurements. Do not modify the
spectrum info
values. If you want to view the information, you can right-click the
spectrum info
wire and select
Custom Probe»Spectrum Info
from the shortcut menu.
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error out contains error information. This output provides standard error out functionality. | ||||||||||||||||||||||||||||||||||||||
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averages completed returns the number of averages completed by the VI at that time. | ||||||||||||||||||||||||||||||||||||||
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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 . |
SVFA Power Spectral Density Subset (N Ch)
|
desired units
specifies if the results are expressed in EU^2/Hz or EU/sqrt(Hz).
|
||||||||||||||||||||||||||||||||||||||
|
scaled signals [EU]
specifies the scaled signals expressed in the selected engineering units. To obtain a properly scaled signal, you can use the SVL Scale Voltage to EU VI or define a virtual channel in National Instruments Measurement & Automation Explorer (MAX).
|
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|
window
specifies the time-domain window used. The default is Hanning.
|
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|
frequency range
specifies the frequency band of analysis. The valid range for the start frequency and for the stop frequency is between 0 and the Nyquist frequency.
|
||||||||||||||||||||||||||||||||||||||
|
dB On specifies whether the results are expressed in decibels. | ||||||||||||||||||||||||||||||||||||||
|
error in describes error conditions that occur before this node runs. This input provides standard error in functionality. | ||||||||||||||||||||||||||||||||||||||
|
averaging parameters
specifies how the VI computes the averaging. The specifications of the parameters include the type of averaging, the type of weighting, and the number of averages.
Note
When you set
averaging mode
to
No averaging
, the VI ignores the
weighting mode
,
number of averages
, and
linear mode
settings.
|
||||||||||||||||||||||||||||||||||||||
|
restart averaging specifies if the selected averaging process has to be restarted. The default is FALSE. When you call this VI for the first time, the averaging process restarts automatically. | ||||||||||||||||||||||||||||||||||||||
|
power spectral densities [EU^2 rms / Hz]
returns the power spectral density for each channel.
|
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unit labels returns the selected engineering units for each channel. | ||||||||||||||||||||||||||||||||||||||
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spectrum info
returns information about the spectrum needed by the Spectrum Extended Measurements VIs, the Display VIs, and the Tone and Distortion VIs.
Note
You must wire
spectrum info
when performing extended measurements. Do not modify the
spectrum info
values. If you want to view the information, you can create a custom probe.
|
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|
error out contains error information. This output provides standard error out functionality. | ||||||||||||||||||||||||||||||||||||||
|
averages completed returns the number of averages completed by the VI at that time. | ||||||||||||||||||||||||||||||||||||||
|
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 . |