GE Medical Systems marquette Dash 2000, Service Manual, Page: 39 / 202

EQUIPMENT OVERVIEW: Theory of Operation
Revision A DASH 2000 Patient Monitor 2-17
2000 412-001
Acquisition PCB
Theory The acquisition PCB, or data acquisition system (DAS), located in the
monitor, is responsible for the acquisition of all vital-sign patient data.
Analog sensor/electrode input signals are amplified and conditioned by
hybrid assemblies, then converted to digital data. The digital patient
data is transferred across an isolation barrier via high-speed
opto-couplers to the processor PCB for analysis and display.
The DAS consists of two isolated (ECG/RESP and NBP, SPO2, TEMP,
IBP) and one non-isolated sections which are separated by a barrier that
is capable of withstanding up to 6000 VDC with respect to earth ground.
Isolation is accomplished by using a coupled inductor power supply and
opto-isolation for signals crossing the barrier.
PCB Block Diagram
Functional Circuits
Functional circuits on the acquisition PCB include:
¥ Isolated power supplies generation,
¥ Patient cable input connector interface,
¥ ECG defibrillator protection,
¥ Patient signal generation (hybrids interface),
¥ Analog-to-digital conversion (patient signals),
¥ Data acquisition system (DAS) processing, and
¥ DAS communication interface and isolation barrier.