Motorola MTR2000 T5544 Instruction / Field Service Manual page 172

VHF 30/40 W Power Amplifier Modules
A/D Converter Circuitry
4
Analog signals from various strategic operating points throughout the PA
module are fed to an A/D converter, which converts them to a digital sig-
nal and, upon request by the Station Control Module, outputs the signal to
the Station Control Module via the SPI bus.
For example, the directional coupler generates a dc voltage proportional to
the reflected power. This signal is converted to a digital signal and sent to
the SCM. If the sense line indicates an impedance mismatch (high VSWR),
the PA is either cut back in power or shut down completely.
68P81096E26-B
09/30/05