GL-T8541 PA
Glenayre Document Number: 9110.01002
DESCRIPTION
09/10/99
Page: 3-2
Copyright © 1997 Glenayre
3.2.3 PA Front
The PA module and exciter are held in place by front panel screws. Two small handles are
mounted to the front panel of the PA which are used when sliding the PA out of the chassis.
3.2.4 PA Rear
With the fan panel closed, only the fan is visible from the back. With the fan panel open,
the metering board, its dc power distribution, the PA I/O connectors, exciter I/O connec-
tors, and the wiring for the cooling fan are all accessible.
3.3 Conceptual Description
This RF power amplifier unit is functionally located between the exciter and antenna. The
task of RF amplification belongs to the PA unit. Modulated RF is sent from the exciter to
the PA input for amplification. A control voltage from the exciter is used in the metering
board to generate an AGC (automatic gain control) signal. The AGC voltage is applied to
the final amplifier stages in the PA and controls the PA output power. A dc sample propor-
tional to the amount of RF output is sent to the metering board and compared to a reference
level generated by the exciter. The error voltage produced is the AGC signal. Any change
in the output power or AGC reference will produce a corresponding change in the AGC lev-
el. In this way, the AGC circuit maintains control of the RF output power in the presence
of power supply and thermal variations.
Table 3-1 Power Amplifier Assemblies
Assembly
Part Number
PA assembly
2100.00135
Driver board
2000.00050
1 to 3 RF splitter
2000.00145
PA board
2000.00027
3 to 1 RF combiner
2000.00106
Metering board
2000.00601
