A/D box

The ActiveTwo A/D Interface forms an ultra-compact, low power front-end (close to the subject) in which up to 280 sensor-signals are digitized. These sensor inputs can be active electrodes measuring EEG, EMG or ECG, or by using the optional buffer box, normal passive electrodes and a range of additional active sensors measuring parameters like respiration, skin conductance, temperature, pulse and force can be used.  Each A/D interface channel consists of a low-noise, DC-coupled, post amplifier with first order anti-aliasing filter, a Delta-Sigma modulator with an over sampling rate of 64, a decimation filter with sharp, fifth order sinc response and high resolution 24-bit output.   The digital outputs of all the AD converters (up to 280) are digitally multiplexed and sent to the PC via a single optical fiber.

Here are some of the benefits of the unique A/D Interface design:

• Special input stage matched with the output of active electrodes.
• Power-supply to active electrodes has auto-shutdown for optimal safety.
• Synchronized 24-bit sampling, no skew, zero-reference principle.
• Expandable (16 up to 280 channels).
• Up to 16 kHz sample-rate per channel (up to 512 kSamples/sec total throughput).
• DC measurement.
• Battery power-supply offers extremely high rejection of all kinds of interference.
• Low power design offers more than 5 hour battery life (280 channel system).
• Fiber optic link ensures optimal patient safety.

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