About electrode voltage bias
Алексей Скородумов <[email protected]>
| Newsgroups | gmane.comp.science.openeeg.general |
|---|---|
| Message-ID | <[email protected]> |
Hi! I'm trying to redesign the openEEG analog board. I'm wondering about the electrode DC shift. Can anyone explain what is the nature of the charge accumulation on gold-plated electrode surface? I understand it has something to do with the sweat ion adsorbtion to electrode surface. So the shift would depend on contact area, sweating, contact surface roughness, etc. How do material properties and signal currents influence this process? I understand that positive/negative shift is defined by anion/cation proportion in the ion film covering the surface. Is this effect influenced by material properties (gold plating) or sweat composition, that is - is the shift predictable (within some probability distribution) based on electrode material, or is it random, depending on the test subject? Can't one get rid of this effect by shorting the input to AGND for some time once in a while? Some sources say the DC offset may be up to 300mV (not sure if it means +/-150mV or +/-300mV). Any comments (as well as literature references) are welcome. Alex ------------------------------------------------------------------------------ HPCC Systems Open Source Big Data Platform from LexisNexis Risk Solutions Find What Matters Most in Your Big Data with HPCC Systems Open Source. Fast. Scalable. Simple. Ideal for Dirty Data. Leverages Graph Analysis for Fast Processing & Easy Data Exploration http://p.sf.net/sfu/hpccsystems