TM 11-5895-1090-34/TO 31 R2-2TSC-152
CHAPTER 2
FUNCTIONING OF EQUIPMENT
Section I. INTRODUCTION
2-1.
General
the terminal and provides interface between up to four
upconverters and a single high power amplifier (hpa) for
This chapter describes the functioning of the amplifier-
multicarrier operation. The amplifier-mixer includes
mixer. It begins with a block diagram description of the
power combining circuitry which provides isolation
amplifier-mixer in section II. This is followed in section
between the multiple input ports, level setting controls
for the individual ports, a broadband amplifier providing
amplifier-mixer which is keyed to the unit schematic
adequate drive to the hpa, a fault alarm circuit, and a
diagram and assembly schematic diagrams.
selectable power monitoring circuit.
2-2.
System Application
The amplifier-mixer is part of the transmitting group of
Section II. BLOCK DIAGRAM FUNCTIONING
2-3.
General
bined signal output from shf combiner assembly Al is
fed shf drive assembly A2. Directional coupler DC1 in
A block diagram of the amplifier-mixer is shown in figure
each shf channel assembly samples the input power for
FO-1. As shown in the block diagram, the amplifier-
application to thermoelectric power monitor assembly
mixer consists of shf combiner assembly A1, shf drive
A7 via variable attenuator AT2 and coax switch S1.
assembly A2, amplifier assembly A3, transient
b. Shf drive assembly A2 consists of an input
suppressor assembly A4, rf low power alarm assembly
isolator (HY1), a 10-db directional coupler (DC1), a
A5, shf output assembly A6, thermoelectric power
diode detector (CR1) for rf input sensing, a gain set
monitor assembly A7, and power supplies PS1 and PS2.
attenuator (ATI) for initial adjustment of the unit, an
2-4.
Block Diagram Functioning
output level attenuator (AT2) which is adjusted by the
front panel OUTPUT LEVEL control, and a fixed output
(fig. FO-1)
attenuator (AT3).
c. Amplifier assembly A3 is a broadband
a. The amplifier-mixer receives 7900-to 8400-
amplifier (twt or fet) which provides a fixed gain
MHz shf inputs from up to four upconverters. These
approximately 40 db to the signal from shf drive
signals are routed via the front panel SHF CHANNEL
assembly A2. The amplified signal from A3 is fed to shf
COMBINER INPUT connectors CH1-CH4 to shf channel
output assembly A6.
assemblies AlAl-AIA4 in shf combiner assembly Al.
d. Shf output assembly A6 consists of an
Each shf channel assembly consists of input and output
input isolator (HY1), two 10-db directional couplers (DC1
isolators, HY1 and HY2, two manually operated variable
and DC2), a diode detector (CR1), a variable attenuator
attenuators AT1 and AT2, and a directional coupler,
(AT1), and an output filter (FL1) which reduces
DC1. Attenuator AT1 in each shf channel assembly is
harmonics and receive-band noise from the signal fed to
adjustable by means of front panel LEVEL ADJUST
the front panel SHF OUTPUT connector. Directional
controls CH1-CH4. The signals from output isolator
coupler DC1 and diode detector CR1 sample the shf
HY2 of each shf channel assembly are added in an in-
output for application to rf low power alarm assembly
phase, four-to-one power combiner.
The power
A5. Directional coupler DC2 samples the shf output
combiner provides a minimum of 18 db isolation
power for application to thermoelectric power monitor
between channels and each shf channel assembly adds
assembly A7 through variable attenuator AT1 and coax
at least 40 db of reverse isolation, providing 58 db
minimum isolation between input signals. The com-
2-1
