Glenayre GL-T8541, Руководство пользователя, Страница: 20 / 90

GL-T8541 PA Glenayre Document Number: 9110.01002
DESCRIPTION 09/10/99
Page: 3-6 Copyright © 1997 Glenayre
Figure 3-3 PA Module Circuit Board Connecting Copper Jumper Straps
3.4.2 Isolator
The optional isolator (not shown) is connected to the RF output of the PA module. It
prevents intermodulation of the RF signal that may occur from nearby transmissions. A
sample detector circuit in the isolator reject load input monitors the reflected power present
at the isolator output connector. The sample is rectified and filtered, providing a dc voltage
proportional to the reflected power.
UHF 3 to 1 Combiner Board
Low Pass Filter and Directional Coupler
(Part of Combiner Board)
UHF
Dr
ive
r Bo
a
rd
UHF 3 to 1 Splitter
P
re a
m
p
key
P
re a
m
p
+
28V
PA
R
F
o
u
t
P
A
RF
Gn
d
PA
+
2
8
V
PA
A
G
C
PA
R
F
o
u
t
P
A
R
F
Gn
d
P
A
+
28V
PA
A
G
C
PA
R
F
o
u
t
P
A
R
F
Gn
d
P
A
+
28V
PA
A
G
C
Gnd
Splitter RF Input
P
A
RF
Inp
u
t
Gn
d
P
A
RF
Inp
u
t
Gn
d
P
A
RF
Inp
u
t
Gn
d
120
W
a
tt
UHF
PA
B
o
a
rd
120
W
a
tt
UHF
PA
B
o
a
rd
1
20
W
a
tt U
H
F
P
A
B
oar
d
PA-1 PA-2 PA-3
RF OUT
RF IN
Metering Board
to PA Interface
Ground
Connection Fuses
1-4
Fuses
6-8
Fuse
5
+dc Input
Connection
Metering Board
to Exciter
Interface