You are here: NI Home > Support > Product Reference > Manuals > Sound and Vibration Measurement Suite 7.0 Help

Owning Palette: Frequency-Domain Measurements Express VIs

Installed With: Sound and Vibration Measurement Suite

Performs a peak search in the frequency domain. You can detect a single or multiple peaks in a magnitude spectrum or power spectrum. You can specify the magnitude threshold and frequency range to fine-tune the peak search.

Dialog Box Options

Block Diagram Inputs

Block Diagram Outputs

Dialog Box Options

Parameter	Description
Spectra	Displays the input spectra. Use the Zoom button to zoom in and out of the display. Use the Cursor button to move the cursors. You can use the two green, vertical cursors to set the Start and the Stop range.
Autoscale	Automatically adjusts the scales of the graph to display the data.
Peaks	Displays the measured peaks in a table.
Input	Specifies whether to operate on a single channel or on N channels. Input signal—Configures the measurement for a single channel or N channels. Changing this selection changes the data types of the input signals and computed measurements.
Configuration	Contains the following options: Search Settings—Specifies the number of peaks to find and the threshold used for the peak search. Search type—Specifies if the peak search locates the maximum peak or all the peaks that are above the Threshold. Threshold—Specifies the level a valid peak must exceed. You also can use the orange, dotted, horizontal cursor on the Spectra graph to set the Threshold. Search Range—Specifies the start and stop frequency, in hertz, for the range used to limit the peak search. You also can use the green, vertical cursors on the Spectra graph to set the search range. Start frequency (Hz)—Specifies the lowest frequency of interest for the peak search, in hertz. Stop frequency (Hz)—Specifies the highest frequency of interest for the peak search, in hertz.

Block Diagram Inputs

Parameter	Description
input spectrum	Specifies the input spectra to use in the peak search measurement.
spectrum info	Contains the spectrum information. The Power Spectrum Express VI and the Zoom Power Spectrum Express VI return this information. Wire the output from these VIs to the spectrum info input.
error in	Describes error conditions that occur before this Express VI runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
frequency range	Specifies the frequency range used to limit the peak search.
peak search settings	Specifies the criteria for the peak search. You can choose to return the maximum peak or multiple peaks. You also can specify the threshold a peak must exceed to be considered a valid peak.

Block Diagram Outputs

Parameter	Description
peaks	Returns the maximum or multiple peaks measured.
unit label	Returns the unit label for the input signal.
error out	Contains error information. This output provides standard error out functionality.
number of peaks	Returns the number of peaks that satisfied the search criteria.