User`s manual

Cerebus® User’s Manual
Revision 13.00 / LB-0028 Page 12
Hardware
Neural Signal Amplifier
The Amplifier receives analog signals directly from the electrodes or via headstages (e.g. unity-gain voltage
followers) depending on the impedance of the electrodes. The analog signals are amplified, filtered (1
st
-order high-
pass at 0.3 Hz and 3
rd
-order low-pass at 7,500 Hz), and digitized (30 kHz, 16-bits at 250 nV resolution), converted
into the optical domain and then transmitted to the NSP via a fiber-optic link, which is immune to electromagnetic
field interference. At a later stage, digital filtering will allow these two signals to be separated and recorded in
different data files.
Figure 2 – Neural Signal Amplifier
The Amplifier ground is not connected to the earth ground. The Amplifier ground is isolated and floating. There are
ESD shunt circuits that will conduct differences of 1000 V or more. The Amplifier can be connected to earth ground
via any one of the four ground pins located on the input side of the Amplifier.
Amplifier Power Supply (APS)
The APS consists of five analog and digital supply channels with monitoring, sequencing, and emergency shutdown
controls.
Figure 3 - Amplifier Power Supply
The On/Off switch is located on the back of the unit. Once it is switched on, the APS will start a power-up sequence
of analog and digital supplies ending with the green ON LED illuminating. When the power switch is turned off this
sequence is reversed and the output of the APS is tied to ground. In the event of an error in voltage or power
delivery, the APS will shut down and a red error LED will turn on. After checking all Amplifier and patient cable
connections for any inadvertent shorting, turn off the APS and turn it back on to reset the error.