User & Service Manual
Trex™ HD Monitoring Amplifier
43
9.4. Testing the Trex HD Monitoring Amplifier
The Trex HD Monitoring amplifier is fully assembled, tested, and calibrated before being shipped to you.
The following sections describe some tests you can perform to verify the performance of the Trex HD
Monitoring amplifier connections. The tests described in this section should be performed regularly to
ensure that the device is functioning as intended.
9.4.1. Calibration and Verification
There is no need to calibrate the software or the Trex HD Monitoring amplifier. All calibration is done at
the factory before the system is shipped. To verify that the Trex HD Monitoring amplifier is correctly
calibrated, perform the following procedure:
1. Connect the Trex HD Monitoring to a Natus computer and turn on the system.
2. Start Natus Database (XLDB).
3. To start a new study, click
New EEG
or
Sleep
.
4. Choose
Edit > Settings > Acquisition
.
5. On the
Acquisition
tab, set the
Reference Electrode
to
Common
.
6. Design four bipolar montages that take the difference of adjacent channels; for example, C3–CZ,
C4–T4, T5–P3, etc.
7. Apply a sine wave of 50 microvolts, peak-to-peak amplitude, 10 Hz to all channels of the group
using a signal generator. Ensure there is a 50 Ohm load on the generator output if the generator
is designed to deliver the specified level into this load.
8. Set the LFF filter to 0.1, the HFF filter to OFF, and the Notch filter to OFF.
9. Verify that no sine wave is greater than 50 microvolts peak-to-peak. 50 microvolts represents gain
match to 1%.
NOTE:
For more information on setting up a montage, consult the
NeuroWorks/SleepWorks User Manual.
9.4.2. Channel Test
While in
Acquisition
mode, a channel test may be performed to check whether a signal is being properly
processed from the amplifier to the display. A channel test applies a test signal to all channels. This
allows you to examine the waveforms on the screen to see if all channels are working.
NOTE:
A channel test does not validate the connection from the patient electrode to
the amplifier input.
To Run a Channel Test
1. Choose
Controls > Channel Test Signal
. The
Channel Test
toolbar appears above the
waveform window.
2. Use the Channel Test toolbar to select the desired wave
shape
,
amplitude
, and
frequency
.
3. To stop the channel test and save the current settings, click
Done
.