# Extracting frequency bands (alpha, beta, gamma etc.) from raw EEG data

**URL:** <https://neurobb.com/t/extracting-frequency-bands-alpha-beta-gamma-etc-from-raw-eeg-data/1052>\
**Category:** Software\
**Tags:** eeg\
**Created:** [May 16, 2019, 5:26am UTC](https://neurobb.com/t/extracting-frequency-bands-alpha-beta-gamma-etc-from-raw-eeg-data/1052 "2019-05-16T05:26:12Z")\
**Posts on this page:** 1\
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**Author:** ![wjcroft](https://neurobb.com/user_avatar/neurobb.com/wjcroft/32/33_2.png) [@wjcroft](https://neurobb.com/u/wjcroft)\
**Post date:** [May 17, 2019, 4:27pm UTC](https://neurobb.com/t/extracting-frequency-bands-alpha-beta-gamma-etc-from-raw-eeg-data/1052/3 "2019-05-17T16:27:01Z")

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If you just want SOME of the bands, for example if you are doing a neurofeedback program that rewards / inhibits certain bands – the alternative is to use band filters instead of FFT. This is a common approach used in VPL’s such as BrainBay, BioEra, Bioexplorer, OpenViBE, neuromore, etc.

An excellent C language IIR filter design library is Jim Peters FIDLIB. It’s actually the engine used by BioEra and BrainBay. A great feature of this library is that the filter type (bandpass, lowpass, highpass, notch; Butterworth, Bessel, etc.) and band edges can all be specified at runtime. This is how the VPL’s allow dynamic changing of these parameters.

[http://uazu.net/fidlib/](http://uazu.net/fidlib/)

> **[uazu/fidlib](https://github.com/uazu/fidlib)**
>
> Fidlib run-time filter design and execution library. CURRENTLY UNMAINTAINED. Consider daschuer/mixxxdj fork if this doesn't work for you. - uazu/fidlib

William

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