Pulsar LPA100, Системное руководство

Страница: 61 / 66

Copyright © 2001 Pulsar Technologies, Inc.
Chapter 10. 100W Combiner Module
10
10.1 100W Combiner Module
description
The function of the 100W Combiner Module, in
essence, is to take the outputs of eight Power
Amplifiers and combine them to form one 100W
output. The 100W Combiner Modules are
completely passive, meaning they require no
power.
The power combiner modules must have equal
amplitude and in-phase carrier frequency signals.
This is to ensure minimum loss in the combiner
circuit. Whatever difference there is between the 2
input signals (4 modules in chassis plus input
from the other 50W chassis) is dissipated as heat
through the high wattage resistors on this module.
In normal operation all of the 12.5W Power
Amplifier modules are putting out equal
amplitude, in-phase signals and there is almost
zero loss in the combiner circuit.
If all the Power Supply modules are not turned on
within a few minutes of one another, the Power
Combiner module balance resistors will heat up.
This is normal since only part of the Power
Amplifier modules would be energized causing
imbalance in the Power Combiner module. This
heating will disappear after all Power Supplies are
turned on and all the Power Amplifier modules are
energized.
10.2 100W Combiner Modules
Test Points
10.2.1 Preliminary checks
In order to check that all eight of the 12.5W Power
Amplifiers are balanced with one another, their
output levels must be checked on the input test
points of the 50W Power Combiner modules in
both chassis. Measure between each one of the
50W Power Combiner's four input test points
(orange, yellow, white, & blue - see Figure 10-1)
TP4 PA#1 IN1, ORANGE
TP3 PA#2 IN2, YELLOW
TP1 COMMON, BLACK
INJECT/EJECT
LEVER
COMPONENT SIDE
SOLDER
SIDE
TP2 PA#4 IN4, BLUE
TP5 PA#3 IN3, WHITE
TP6 OUTPUT, RED
Figure 10–1. 50W Combiner Module
Schematic CA30-CMBMN
Part List CA40-CMBMN