HDEEG Facility

The Geodesic EEG system can acquire a 256 channel EEG.

Acquisitions can be done through two available networks:

  • HydroCel GSN Sensor NETs, MR compatible (available sizes: 54-56 cm, 56-58cm)
  • HydroCel GSN Sensor NETs, not MR compatible (available sizes: 54-56 cm, 56-58cm)

Networks are connected to a Net Amps 400 amplifier:

Feature Net Amps 400
Coupling DC
Chip for A/D conversion ADS1298
A/D resolution 24 bits
On-board microprocessor Intel ATOM 1.6 GHz 32-bit
FPGA DSP FIR filter signal processor
Embedded operating system Linux
I/O connection Fiber optic ethernet
Digital (TTL) inputs 16 bits (8 supported in hardware)
Input impedance ≥ 1 G ohm
Sensitivity (AC model)/precision 0.023 µV/bit
Bandwidth DC to 2000 Hz
Input noise < 0.8 µVRMS
Input range ± 200 mV
Common mode rejection rate ≥ 90 dB
Isolation mode rejection rate ≥ 120 dB
Sampling rate supported 8 KHz* (available: 0.25, 0.5, 1 KHz)
Power consumption 15 Watts
*Amp Server PRO SDK is required to realize the highest sampling rates

Also available are:

  • 2 GES Clock Sync I/O
  • 2 MR compatible electrodes for ECG measurements
  • E-Prime Experiment Control System for stimulus presentation
  • Faraday Cage