Physio Control LIFEPAK 9 - Page 31

Main PCB Assembly
(803715)
Description 1
The Main PCB Assembly, illustrated in Figure 1-4, consists of three major
circuits: the Preamp, the System Controller, and the Display/Recorder
Interface. The Preamp circuitry converts the ECG from the patient cable to
sampled ECG. The converted ECG signal is optically connected to the
System microprocessor which performs the initial ECG signal processing.
The System microprocessor is central to the System Controller circuitry. The
System Controller provides the interface between the operator inputs and the
instrument functions. The Display/Recorder Interface controls the CRT and
recorder displays according to the information supplied by the System
microprocessor.
The three major circuits control the functions listed in Table 1-2. Each
circuit is described in the following paragraphs.
Table 1-2 Main PCB Functional Circuits
Preamp
System Controller
Display/Recorder Interface
Isolated Power Supply
Front-End Protection
Lead Select
(© Optical Interface
Instruction Decoding
Instrumentation Amplifier
Filtering
DC Restore
Echo
Front and Rear Panel
Controls Interface
Audio Alarms
Charge Control
VO Protection
Display/Recorder Controller
System Clock
Address Decode
Display Gate Array
Video RAM
Font EPROM
Program EPROM
Program RAM
Recorder Power
Motor Speed Control
Printhead Control
Printhead Resistance Evaluation
© August 1993 Physio—Control
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