SVL Exp Avg Sound Level VI

SVL Exp Avg Sound Level VI

Owning Palette: Sound Level VIs

Requires: Sound and Vibration Toolkit

Computes the exponential averaged sound level of scaled signal [EU]. scaled signal [EU] should have a zero DC component. Wire data to the scaled signal [EU] input to determine the polymorphic instance to use or manually select the instance.

The Sound Level VIs return respective sound pressure levels in dB rms relative to the reference. By default, a sound pressure level of 20 uPa rms is used as the reference for conversion to dB. In contrast, peak and peak-to-peak sound pressure levels are referenced to 20 uPa pk.

Details  

SVL Exp Avg Sound Level (1 Ch)

	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). t0 specifies the start time of the waveform. dt specifies the time interval in seconds between data points in the waveform. Y specifies the data values of the waveform.
	exponential mode specifies the exponential averaging mode. The Custom option enables you to specify any positive time constant. 0 Slow t = 1 s 1 Fast (default) t = 125 ms 2 Impulse t = 35 ms rising and 1.5 s falling 3 Custom
	time constant specifies the time constant in milliseconds used for exponential averaging if exponential mode is set to Custom. In all other cases, this parameter is ignored. The default is 125.00 ms.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	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.
	exp avg sound level [dB EU] returns the exponential averaged sound level expressed in decibels.
	unit label returns the selected engineering units.
	actual time constant [ms] returns the time constant actually used for the selected exponential averaging mode. Slow mode returns 1000 ms. Fast mode returns 125 ms. Impulse mode returns 35 ms.
	error out contains error information. This output provides standard error out functionality.
	maximum sound level [dB EU] returns the maximum value from exp avg sound level [dB EU]. The default is 0. The maximum value returned is the greatest value measured since averaging last restarted.

SVL Exp Avg Sound Level (N Ch)

	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 virtual channels in National Instruments Measurement & Automation Explorer (MAX). t0 specifies the start time of the waveform. dt specifies the time interval in seconds between data points in the waveform. Y specifies the data values of the waveform.
	exponential mode specifies the exponential averaging mode. The Custom option enables you to specify any positive time constant. 0 Slow t = 1 s 1 Fast (default) t = 125 ms 2 Impulse t = 35 ms rising and 1.5 s falling 3 Custom
	time constant specifies the time constant in milliseconds used for exponential averaging if exponential mode is set to Custom. In all other cases, this parameter is ignored. The default is 125.00 ms.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	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.
	exp avg sound levels [dB EU] returns the exponential averaged sound levels expressed in decibels.
	unit labels returns the selected engineering units for each channel.
	actual time constant [ms] returns the time constant actually used for the selected exponential averaging mode. Slow mode returns 1000 ms. Fast mode returns 125 ms. Impulse mode returns 35 ms.
	error out contains error information. This output provides standard error out functionality.
	maximum sound levels [dB EU] contains the maximum sound level [dB EU] for each channel. The maximum value returned is the greatest value measured since averaging last restarted.

SVL Exp Avg Sound Level Details

You can attenuate the DC component with hardware AC-coupling filters and with software high-pass filters. This VI returns the exponential averaged sound level computed after each individual sample of the time record.

The SVL Exp Avg Sound Level VI returns the sound level as an array that is the same size as the original time record.

The SVL Exp Avg Sound Level VI requires a continuous input data stream. An internal mechanism automatically detects any sampling discontinuity and resets the filters.