FilterContinuousVariableEx

Filters a continuous variable using the specified frequency filter. Returns a reference to the new variable with filtered values.

Syntax

FilterContinuousVariableEx(contVar, filterType, filterImplementation, filterOrder, freq1, freq2, ripple=1.0)

Parameters

Parameter	Type	Description
contVar	variableReference	Reference to the variable.
filterType	string	The type of the filter. Should be `'Lowpass'`, `'Highpass'`, `'Bandpass'`, `'Bandstop'` or `'Notch'`.
filterImplementation	string	Filter implementation. Should be `'IIR Butterworth'`, `'IIR Chebyshev'`, `'FIR Bartlett'`, `'FIR Blackman'`, `'FIR Hamming'` or `'FIR Hann'`.
filterOrder	number	The number specifying the filter order. Use 1 to 12 for IIR filters, 4 and higher for FIR filters. If FIR filter order is odd, order+1 is used.
freq1	number	Filter frequency parameter (in Hz). See comments below.
freq2	number	Filter frequency parameter (in Hz). See comments below.
ripple	number	Filter ripple. Used for `IIR Chebyshev` filter only.

Return

Returns reference to the new continuous variable with filtered values.

Note

Python only.

If the filter type is Lowpass or Highpass, freq1 is a cutoff frequency and freq2 is not used.

If the filter type is Bandpass or Bandstop, freq1 is the minimum of the frequency range and freq2 is the maximum of the frequency range.

If the filter type is Notch, freq1 is the center of the Notch filter and freq2 is the width of the Notch filter. Standard Notch filter is used.

Examples

The following sample script applies Hamming FIR band-pass filter to the variable ContChannel01. The result of filtering is then saved in a continuous variable Cont1BandFiltered. The filter order is 51 and the frequency band is from 1000 Hz to 2000 Hz.

Python

import nex
doc = nex.GetActiveDocument()
var = doc["ContChannel01"]
doc["Cont1BandFiltered"] = nex.FilterContinuousVariableEx(var, "Bandpass", "FIR Hamming", 51, 1000, 2000)