Strange spike at start of of EEG recording
My goal is to create a program that record the EEG signal during subject movement.
I'm using Cython Daisy with Cortex Mark IV and dry electrode. In my program, I used BrainFlow library to connect and recorded the EEG. However, When I apply a filter, there is a strange noise at the begining and ending of the recorded signal everytimes I start record a new session as follow
Raw signal
Notch filter at 50 and 60Hz
0.4-40Hz Butterworth band-pass 4th order
Could you provide some idea which cause this kind of problem?
Comments
Hi Goragodp,
Please read this thread about filtering out the DC offset.
https://openbci.com/forum/index.php?p=/discussion/201/large-millivolt-data-values-fbeeg-full-band-eeg
The transient / large excursions at the very start of EEG amplifier operation is normal and to be expected. Just ignore the first second after the session start.
Regards, William
Thank you for your explanation and reference resource.