Motorola MTR2000 T5544 Instruction / Field Service Manual page 162

1
DESCRIPTION
The CLN1233 Exciter Module is described in this section. A general description, identification of inputs and out-
puts, a functional block diagram, and functional theory of operation are provided. The information provided is
sufficient to give service personnel a functional understanding of the module, allowing maintenance and trouble-
shooting to the module level. (Refer also to the Maintenance and Troubleshooting section of this manual for de-
tailed troubleshooting procedures for all modules in the station.)
General Description
Overview of Circuitry
Motorola Inc., 2005
All Rights Reserved
Printed in U.S.A.
MODEL CLN1233 (132 to 174 MHz)
The Exciter Module (in conjunction with the Power Amplifier Module)
provides the transmitter functions for the station. Contained within a met-
al module housing, the exciter board generates a low-level modulated RF
signal which is input to the power amplifier module for further amplifica-
tion and output to the transmit antenna. The Exciter Module interfaces
directly with the Station Control Module, which provides control signals
and monitoring, and routes transmit audio to the exciter.
These Exciter Modules differ only in the range of operation, as shown in
the title of this section. Unless otherwise noted, the information provided
in this section applies to all models.
The exciter board contains the following circuitry:
• Frequency Synthesizer Circuitry – consisting of a phase-locked loop
and VCO, generates a modulated RF signal at the transmitter carrier
frequency
• RF Isolation Switch – allows the SCM to turn on/off the exciter out-
put signal to the power amplifier module
• A/D Converter Circuitry – converts analog exciter status signals to
digital format for transfer, upon request, to Station Control Module
• Local Power Supply Regulation/Filtering – accepts +8V, +10V and
+15V inputs and outputs +5V, +10V, and +15V operating voltages.
Government & Enterprise Mobility Solutions
1301 E. Algonquin Road, Schaumburg, IL 60196
EXCITER MODULE
68P81096E22-C
09/30/05-UP