BioSemi.nl

Thanks, Parabelo, for the explanation about the odd harmonics being from the power lines...I wonder why only the odd harmonics? We are recording EEG on 64+3 channels. This is what our spectral analysis looks like for the entire recording: http://img338.imageshack.us/img338/7734/50hzandoddharmonicsno...

We have observed the same phenomenon noted by Parabelo: quite strong noise at 50, 150, and 250 Hz (we are sampling at 512 Hz). While it is the case that we are not recording in a room with magnetic shielding, we have made eery effort to keep potential sources of noise as far as possible away from th...