This function can be used to apply a Fourier filter to any data consisting of x- and y-columns. Supported filter types are:
Band reject (band block)
where any of them can have the form
Butterworth (order 1 to 10)
Chebyshev type I or II (order 1 to 10)
Optimal "L"egendre (order 1 to 10)
Bessel-Thomson (any order)
The cutoff value(s) can be specified in the units frequency (Hertz), fraction (0.0 to 1.0) or index of the data points.