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Owning Palette: Frequency-Domain Measurements Express VIs

Installed With: Sound and Vibration Measurement Suite

Performs fractional-octave analysis, including 1/1, 1/3, 1/6, 1/12, and 1/24 octave for a single channel or N channels. You also can apply A-, B-, or C-weighting to the octave spectrum.

Dialog Box Options

Block Diagram Inputs

Block Diagram Outputs

Dialog Box Options

Parameter	Description
Octave Spectrum	Displays the octave spectrum for a single channel or N channels.
Filter settled	Returns TRUE when all octave filters are settled.
Input	Specifies if the measurement operates 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	Specifies the configuration settings. Bandwidth—Specifies the bandwidth and has the following options: 1 Octave 1/3 Octave (Default) 1/6 Octave 1/12 Octave 1/24 Octave Weighting—Specifies one of the following weighting types to apply to the octave spectra: Linear (Default)—Applies no weighting to the octave spectrum. A Weighting—Applies A-weighting to the octave spectrum. B Weighting—Applies B-weighting to the octave spectrum. C Weighting—Applies C-weighting to the octave spectrum. Frequency Range—Specifies the frequency range parameters for the octave analysis. Choose Frequency Values—Specifies the way you select the Low frequency (Hz) and High frequency (Hz) values. Frequency List allows you to select from a list of values. Arbitrary Values allows you to specify an arbitrary frequency range. Low frequency (Hz)—Specifies the frequency of the lowest octave band. This option appears when you select Frequency List from the Choose Frequency Values pull-down menu. Low frequency (Hz)—Specifies the frequency of the lowest octave band. This option appears when you select Arbitrary Values from the Choose Frequency Values pull-down menu. High frequency (Hz)—Specifies the frequency of the highest octave band. This option appears when you select Frequency List from the Choose Frequency Values pull-down menu. High frequency (Hz)—Specifies the frequency of the highest octave band. This option appears when you select Arbitrary Values from the Choose Frequency Values pull-down menu. Total band power (dB)—Displays the total band power of the octave spectrum.
Averaging	Specifies the averaging parameters. Averaging type—Specifies the averaging type. Weighting mode—Specifies the weighting mode from the following options: Linear—Applies equal weighting to all the data. Exponential (Default)—Applies more weight to the most recent data. Equal Confidence—Applies more weight to the most recent data, using a specific time constant for each band. Peak—Maintains the peak level for each band. Exponential Averaging—Specifies the exponential averaging parameters. Response mode—Specifies the exponential averaging mode from the following options. This option is available only when you set Weighting mode to Exponential. Slow—time constant = 1 s Fast (Default)—time constant = 125 ms Impulse—time constant = 35 ms rising and 1.5 s falling Custom—Any strictly positive Time constant (s) Time constant (s)—Specifies the time constant, in seconds, for exponential averaging if you set Response mode to Custom. Equal Confidence Averaging—Specifies the equal confidence averaging parameters. Level (dB)—Specifies the confidence value in decibels to use if you set the Weighting mode to Equal confidence.

Block Diagram Inputs

Parameter	Description
input signal	Specifies the input signals.
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.
restart averaging	Specifies whether to restart the selected averaging process. The default is FALSE. When you call this Express VI for the first time, the averaging process restarts automatically.

Block Diagram Outputs

Parameter	Description
octave	Returns the octave spectrum.
total band power	Returns the total band power in the octave spectrum.
unit label	Returns the unit label for the input signal.
error out	Contains error information. This output provides standard error out functionality.
filter settled	Returns TRUE when all octave filters are settled.
octave info	Returns octave information.