Service manual

Neurodiagnostic Instruments Service Manual
3 - 58 Revision 2/18/05
Two analog to digital converters change the filtered
analog signals to a series of digital samples. These
samples are processed by a digital signal processor
(DSP) and transferred to the host PC via a Universal
Serial Bus (USB) port. Information for synchronizing
the data with stimulus events is placed into the data
stream as well.
The digital patient data samples are also mixed and
presented via a Digital to Analog Converter (DAC) to
an audio amplifier and speaker for listening.
Control and status information from the host PC to the
amplifier are exchanged along with the data on the
single USB interface cable.
Stimulus Artifact Suppression is implemented in the
amplifier and may be used to help counter the effects of
electrical stimulus on the measured patient signals. This
feature may be applied to individual channels or may be
enabled or disabled globally.
Testing
The Endeavor CR USB Diagnostics are the primary tool
for testing the amplifier system. The AutoTest checks
for proper communication between the base unit and
amplifier module, and the Headbox Test uses an
internally generated calibration pulse to check the signal
path integrity from the electrode input connectors on the
headbox to the host computer.