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The effects of high input-impedance on EEG data quality

EGI has long been known for the ability to collect high quality EEG data with no abrasion to the scalp.  While some might think that this is made possible because of the design of the Nets, it is actually due to the technology of modern amplifiers.   The entire family of EGI ampliers are high-input impedance amplifiers. In EGI's published paper "Scalp electrode impedance, infection risk and EEG data quality", it is shown that when the amplifier's "input-impedance is high enough (200 MΩ), there is negligible signal attenuation when using electrodes without abrasion." Further, "circuit analysis suggests that, for this input impedance, scalp-electrode impedances up to 200 kΩ still allow for accurate signal acquisition."

The input impedance of the Net Amps 400, which represents EGI's newest technology platform, is ≥ 1.0 GΩ.  This is higher than the previous generation of EGI's amplifier, the Net Amps 300, which has an input impedance of ≥ 200 MΩ. 

All current iterations of EGI techology, including the GES 400, the GES 400 MR and the GTEN 100 systems, are all built upon the NA 400 technology platform. 


Additional Info

  • Product Type: GES 400, GES 400 MR, GES 300, GTEN 100
  • Information Type: Theoretical Background
Last modified on Tuesday, 31 January 2017 20:41

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