The Refa is a multi-channel amplifier system for stationary use. The Refa includes unipolar electrophysiological inputs (ExG) but can also include a number of bipolar electro-physiological inputs (BIP) and auxiliary inputs (AUX)
The unipolar electro-physiological inputs are configured as a reference amplifier: all channels are amplified against the average of all connected inputs. Using these channels, signals like: EEG, EMG, ECG, EOG, EGG etc. can be measured.
The bipolar electro-physiological inputs are used to measure two physiological signals differntailly to each other. Signals like ECG, EMG or EOG can be measured this way.
The auxiliary inputs can be used for measuring sensor signals like temperature, pH, respiration, movements, force, angle etc.. Each of these channels has a +5V and –5V output in order to use active sensors or sensor modules.
The Refa system can be delivered with different number of input channels. Refa’s with 24, 32, 40, 72 and 136 channels are available. It is also possible to cascade two Refa’s, resulting in a total channel count of 272 channels.
The Refa is delivered including an external power supply, which plugs into the mains socket. The Refa is connected to a PC by means of a bi-directional glass fiber. The systems with lower channel count (24, 32 or 40 channels) are deliverable with either a “head” or a “row” input configuration. The ‘head” configuration adheres to the electrode positions in the International 10-20 system as used in EEG (ElectroEncephaloGraphy) and EP (Evoked Potential) recordings.
The design of the Refa integrates the true DC reference amplifier. The active shielding guarantees optimal signal quality, no mains or other interference and no movement artefacts. Since the system includes no hardware filtering, all amplifier channels are identical and can be used for any desired signal.