I saw in old thread some posted:
Spectral monitoring of EEG signals is pretty straightforward. Normally, the time domain signal is broken into short epochs of a few seconds and an FFT is performed on that data array. The data from the FFT is binned into frequency ranges according to standard EEG definitions: Delta, (0-4Hz), Theta (4-8Hz), alpha (8-12Hz) , etc. The Peak power value in that frequency range and/or the cumulative power (total power in that bin) is reported. Then the next segment of EEG data is processed and this continues either in real-time or on a prerecorded file of EG. This process is duplicated for each channel of data corresponding to different locations on the brain.
I need to get a ratio of the power levels of two bands, 0-5 Hz and 20-40Hz, of a single channel EEG. How do bin the output of FFT? Am I using the correct Vi for this (FFT Spectrum (Mag-Phase) VI )? The Spectal Measurements Express VI look like it might be able to do this too but I cannot figure how to bin the ranges. Can I get the area under the plot some how?
We are are using a NI PCI-6221 with a NI BNC2090A box and of course the proper saftey precautions for the subjects.
Thanks for your help.