Butterworth IIR Filter

C/C++ Equivalent: NISCOPE_VAL_BUTTERWORTH_FILTER

The input waveform is filtered with a Butterworth IIR algorithm. The type of the filter is specified by Filter Type as any of the following values:

  • lowpass
  • highpass
  • bandpass
  • bandstop

The order of the filter is specified by the Filter IIR Order property or the NISCOPE_ATTR_MEAS_FILTER_ORDER attribute. Also, a number of points equal to Percent Waveform Transient property or the NISCOPE_ATTR_MEAS_FILTER_TRANSIENT_WAVEFORM_PERCENT attribute divided by 100 times the input size are eliminated from the beginning of the filtered waveform so the transient response of the filter does not affect further measurements.

Units

Volts

X Units

Seconds (nonlinear time delay)

Resulting Array Size

inputSize × (1 – Percent Waveform Transient property / 100)

or

inputSize × (1 – NISCOPE_ATTR_MEAS_FILTER_TRANSIENT_WAVEFORM_PERCENT attribute / 100)

Related Topics

Butterworth Filters