SVT Fractional Octave Filtering VI

SVT Fractional Octave Filtering VI

Owning Palette: Weighting and Filtering VIs

Requires: Sound and Vibration Toolkit

Performs fractional octave filtering on scaled signal [EU] in accordance with either the ANSI S1.11-2014 standard or the IEC 61260-1:2014 standard.

You can use this polymorphic VI to perform fractional octave filtering on a single channel or on N channels. The data type you wire to the scaled signal [EU] input determines the polymorphic instance to use.

Details  

SVT Fractional Octave Filtering (1 Ch)

	coerce to nearest midband frequency? specifies if the midband frequency will be coerced to an exact midband frequency of a standard octave band. The default is FALSE.
	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.
	bandwidth specifies the bandwidth of the 1/n octave filters. 0 1 octave (default) 1 1/3 octave 2 1/6 octave 3 1/12 octave 4 1/24 octave
	midband frequency specifies the midband frequency of the octave bandpass filter. It could be any value between 20 Hz to 20,000 Hz.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	reset filter specifies if the octave filters have to be reset. The default is FALSE. The filters are automatically reset the first time this VI is called.
	filtered signal [EU] returns the filtered signal. t0 returns the start time of the waveform. dt returns the time interval, in seconds, between data points in the waveform. Y returns the data values of the waveform.
	actual midband frequency [Hz] returns the midband frequency actually used for octave bandpass filter design.
	error out contains error information. This output provides standard error out functionality.
	settled? returns TRUE when the octave filter is settled.

SVT Fractional Octave Filtering (N Ch)

	coerce to nearest midband frequency? specifies if the midband frequency will be coerced to an exact midband frequency of a standard octave band. The default is FALSE.
	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.
	bandwidth specifies the bandwidth of the 1/n octave filters. 0 1 octave (default) 1 1/3 octave 2 1/6 octave 3 1/12 octave 4 1/24 octave
	midband frequency specifies the midband frequency of the octave bandpass filter. It could be any value between 20 Hz to 20,000 Hz.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	reset filter specifies if the octave filters have to be reset. The default is FALSE. The filters are automatically reset the first time this VI is called.
	filtered signals [EU] returns the filtered signals. t0 returns the start time of the waveform. dt returns the time interval, in seconds, between data points in the waveform. Y returns the data values of the waveform.
	actual midband frequency [Hz] returns the midband frequency actually used for octave bandpass filter design.
	error out contains error information. This output provides standard error out functionality.
	settled? returns TRUE when the octave filter is settled.

SVT Fractional Octave Filtering Details

For both standards, the sampling frequency must be at least three times the highest midband frequency for octave analysis and at least 2.5 times the highest midband frequency for 1/3, 1/6, 1/12, or 1/24 octave analysis. Available bandwidths are 1/1, 1/3, 1/6, 1/12, and 1/24 octave.

To ensure a continuous filtering operation, call this VI the first time with reset filter (F) set to TRUE and then call it with reset filter (F) set to FALSE.

To design a standard octave filter, set coerce to nearest standard midband frequency? to TRUE.