Large <1Hz, no 8-13Hz
Posted: Sun Jun 05, 2011 12:19 pm
Hi all,
I have an openEEG Modular EEG device (amplifier stage is modeeg; the digital stage has been adapted for usb etc.).
I use sintered Ag/AgCl-Electrodes. Impedace is checked and was below 15k.
I made a test acquisition with DRL and - of Ch1 connected to neutral positions (checkbone near the ear), + connected to Cz.
I find low 50 Hz noise, but large signal below 1Hz and almost no signal in the 8-13Hz range even when eyes closed.
I standard papers I read that the amplitude in the range 8-13Hz should be around 9µV.
Could anyone help me to make / check a standard recording in order to check if the hardware works as intended?
Further informations:
------------------------------
I attached the raw file in csv-reader format and a simple scenario which brings the data in the µV range and extracts/displays:
raw data
<1Hz
8-13Hz
power spectrum
The power spectrum does not display anything, but I can't find my error...
I have an openEEG Modular EEG device (amplifier stage is modeeg; the digital stage has been adapted for usb etc.).
I use sintered Ag/AgCl-Electrodes. Impedace is checked and was below 15k.
I made a test acquisition with DRL and - of Ch1 connected to neutral positions (checkbone near the ear), + connected to Cz.
I find low 50 Hz noise, but large signal below 1Hz and almost no signal in the 8-13Hz range even when eyes closed.
I standard papers I read that the amplitude in the range 8-13Hz should be around 9µV.
Could anyone help me to make / check a standard recording in order to check if the hardware works as intended?
Further informations:
------------------------------
I attached the raw file in csv-reader format and a simple scenario which brings the data in the µV range and extracts/displays:
raw data
<1Hz
8-13Hz
power spectrum
The power spectrum does not display anything, but I can't find my error...