Electrode Noise Levels

edelic · Post by **edelic** » Fri May 13, 2005 7:56 am

Hi!

What is the typical noise level introduced by Biosemi's Active electrodes?
Thanks!

walrus · Post by **walrus** » Fri Apr 14, 2006 6:40 pm

I'm also interested in this question. I have to analyze some data based on single trial basis.

I found that for some subjects the noise level can be as large as 50 uV. After performing skin preparation (I know Biosemi does not need this), the noise level is still high.

May I ask how to reduce the noise?

Post by **Coen** » Tue Apr 18, 2006 11:08 pm

When measured with the electrodes in saline (salt water), the electrode noise is very close to the noise level of the electronic circuitry (a few microvolt peak-to-peak, see specs).

Please explain how you have determined the electrode noise when measuring on a subject skin. In other words: which method did you use to differentiate between noise and physiological signals (background EEG, muscle activity, etc.) ?

Best regards, Coen (BioSemi)

walrus · Post by **walrus** » Thu Apr 20, 2006 12:19 pm

I just asked the subject to fully relax and look at the signal of bipolar lead (EMG).

As you said, maybe the subject was not relaxed enough so that there are some physiological "noise".

If we do have concern about noise, may we put the active electrodes in saline water to do a simple test? (as you said in your reply)

Or what's the standard way to measure noise?

By the way, I got good result of my previous study. Thanks for your help.