# Bandpassing EEG's using Mathematica's Bandpass Function

Let's say we have an EEG signal approximated using a fractional Brownian motion:

EEG[hurst_,t_low,thigh_,tinc_]=RandomFunction[
FractionalBrownianMotionProcess[hurst], {tlow, thigh, tinc}, 1]


for some parameters hurst_, tlow_, thigh_, tinc_.

The literature on EEG's state that alpha waves are obtained by using a bandpassing filter in the range 14-40 Hz, more or less...

data = EEG[0.4,0,1,0.01]
BandpassFilter[Flatten[data[[2, 1]]], {0.14, 0.40}];


My question is with regards to the BandpassFilter parameters. Does choosing 0.14 and 0.40 effectively yield the 14-40Hz range? Basically, what are the units of the BandpassFilter function in Mathematica

• You need a factor of π and also need to mention the SampleRate. See my answer here for an example. – rm -rf Aug 24 '14 at 20:17