ActiveTwo - Hyper-Sampling Edition
  • ActiveTwo - Hyper-Sampling Edition

  • Hyper Sampling EEG System with up to 262,144 Hz sampling

  • Product No: NS-1076
  • Manufacturer: Biosemi
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BioSemi sets new standards with its latest hyper-sampling active electrode EEG system. The ActiveTwo is now available as a hyper-sampling system built upon the successful ActiveTwo AD-box with 8 special 1-channel modules (8 channel EEG system). The system looks the same as a standard ActiveTwo with exception of the top: the hyper-sampling version uses only the 8 EX (external) inputs on the top, the 8 SCSI (86-pole) connectors are not present on the hyper-sampling version.

Its main application is EEG/ABR on subjects with cochlear implants, as cochlear implants generate vast amounts of high frequency interference covering the EEG. When the high frequency interference is sampled accurately together with the EEG, the interference can be calculate out of the signal and the clean EEG will be recovered. Currently, the high frequency interference is smeared out to lower frequencies in the EEG bandwidth, and EEG cannot be recovered. No other EEG amplifier can measure such a signal with this accuracy (fast slew rate, minimal ringing).

Thanks to the ActiveTwo system's latest active electrode technology, setup time is fast and does not require skin preparation. The ActiveTwo system is compatible with MEG/MCG and suitable for EEG, ECG as well as EMG measurements, allowing graphical programming (LabVIEW) on PC, Mac and Linux operating systems. The ActiveTwo is battery powered with high-speed fibre optic data transfer, isolates the subject optically and galvanically from the mains power supply. The BioSemi ActiveTwo system is specifically designed to be used in research applications only. The system benefits from freely configurable hardware and completely open-source software.


System Features

  • Latest SAR (Successive-Approximation-Register) ADC technology providing up to 262,144 Hz sampling rate.
  • Second generation active electrode: smaller size, less weight and strain-relief.
  • Flexible coloured electrode labelling system.
  • 24-bit ADC per channel.
  • Improved digital resolution, with a LSB (Least Significant Bit) value of 31.25 nV.
  • Full DC operation, largest input rangein the industry (524mVpp).
  • User selectable sample-rate, high sampling available.
  • Full range of auxiliary sensor inputs available.


Technical Specifications

Analog-to-Digital conversion: 4x oversampling 24 bit SAR converter with integrated decimation (anti-aliasing) filter
Resolution: LSB = 31.25 nV (same as standard ActiveTwo)
Input range: +/- 262 mV (0.5 V pk-pk, same as standard ActiveTwo)
Sample rate: 262,144 Hz (16x standard ActiveTwo)
Bandwidth: 87 kHz (30x standard ActiveTwo)
Noise: see spectrum and 0.1-10 Hz plot (noise density same or lower than standard ActiveTwo)
Additional specifications: Same as the ActiveTwo, see more on the ActiveTwo product page.


Noise Specifications

The Hyper-Sampling ActiveTwo EEG system has undergone several tests to ensure the quality of the EEG data. We're proud to present the increased signal quality by illustrating the noise specifications of the Hyper-Sampling ActiveTwo in the following plots:

Noise Spectrum of the Hyper-Sampling ActiveTwo

Noise spectrum, EX1 vs EX2 (50 and 150 Hz spikes due to mains interference)

Pink Noise plot of the Hyper-Sampling ActiveTwo

1/f noise (Pink Noise), EX1 vs EX2, 0.1 to 10 Hz.

Slew rate plot of the Hyper-Sampling ActiveTwo

Response to a 20 kHz, 40 mVpp square wave as a simulated high-frequency interference signal. The plot shows a 1.0 millisecond epoch, Y-axis in microVolt, each square dot is an actual sample. The plot shows the fast slew rate of the complete system (very steep edges) and the minimal ringing of the decimation filter.

Noise Spectrum of the Hyper-Sampling ActiveTwo

Noise Spectrum of the Hyper-Sampling ActiveTwo

Pink Noise plot of the Hyper-Sampling ActiveTwo

Pink Noise plot of the Hyper-Sampling ActiveTwo

Slew rate plot of the Hyper-Sampling ActiveTwo

Slew rate plot of the Hyper-Sampling ActiveTwo

Please note: Important! This product is for research applications only. Not a medical device as defined in EU directive 93/42/EEC. Not designed or intended to be used for diagnosis or treatment of disease.