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Figure 3-9 Microcontroller function flow diagram
Lead fault control:
This block accepts signals from the digital module and the lead fault
logic interface to control a series of light-emitting diodes (LEDs)
used to indicate the status of the lead wires attached to the patient.
This block does not perform any radio transmission function.
RF module:
The RF module includes the VCO, synthesizer, TCXO, buffer
amplifier, power amplifier, and antenna filter. The TCXO provides a
reference for the synthesizer. The synthesizer also accepts an input
from the VCO. The output of the synthesizer loop drives the buffer
amplifier and the power amplifier which, when connected to the
antenna filter, provides power to the dipole antenna port (
RF Out
).
Digital module:
The digital module accepts 9-volt DC battery input (
Battery
Connector
) and produces operating voltages for the ECG sub-
system (
ECG Power
). Reverse battery protection and regulation are
performed by Q1, U1, U2, U27, and U31. The low-battery detection
circuitry is U1 and Q24.
