GE Dash 3000 Service Manual page 46

2-26
Equipment overview: Theory of operation
The DAS block diagram with Nellcor 05 DAS PCB assembly consisting of
three sections:
Section
ECG/Respiration Separately isolated section includes a 7.3728MHz 68HSC05
microcontroller, A/D conversion, signal processing hybrids and
DC-DC isolation converter.
Main DAS Separately isolated section includes a 22.1184MHz Motorola
MC68332 microcontroller with FLASH and SRAM memory, an
Analog Devices ADSP-21062 32-bit floating point digital signal
processor running at 12.096MHz, A/D conversion, signal
processing hybrids/modules and DC-DC isolation converter.
Non-isolated circuits Includes serial and parallel host interfaces and NBP pump, valves,
and over-pressure circuitry.
The DAS design includes the Nellcor MP100 Module technology. Nellcor
SPO2 is classified as motion-resistant. It uses advanced digital signal
processing algorithms to extract very low-level SPO2 signals in the
presence of artifact induced noise.
The DAS contains all circuitry necessary to support the MP100 Module.
The Nellcor MP100 Module contains:
All SPO2 front end circuitry, such as the digitally programmable

photodetector signal conditioning, A/D conversion, digitally
programmable back-to-back LED IR/RED emitter drive and on-board
diagnostic / sensor identification signal processing circuits.
A digital signal processor (DSP), clock circuitry, and program

memory. The Nellcor SPO2 algorithms executes on the DSP. No
external memory interface is provided. The DSP is "reset-able" by the
DAS CPU.
A UART for communication of commands and data.

Parameter functions of the DAS with Nellcor OxiMax SPO2,
four BP channels and Dinamap SuperSTAT NIBP
Except for the SPO2 parameter and additional 2 IBPs, the DAS with the
Nellcor OxiMax SPO2 parameter supports the same parameters as DAS
with the GE Ohmeda SPO2 parameter. Refer to
Probes and cable
The DAS is intended for use only with Nellcor digital probes. It is not for
use with non-Nellcor probes or with Nellcor R-cal (resistor id) probes. An
adapter cable is used to interface the probes to the DAS front panel
Nicolay connector.
Dash 3000/4000/5000
Description
"ECG" on page 2-20.
2000966-542D