TM 11-5895-1090-34/TO 31 R2-2TSC-152
tiometer R3 on transient suppressor assembly A4. A
switch A1S1.
e. Power monitoring is accomplished by a
reduction in rf output level below this preset threshold
actuates a FAULT lamp on the front panel. The second
thermoelectric power monitor A7 in conjunction with
channel of the comparator accepts an analog signal
five-pole coaxial switch (A1S1). The coaxial switch can
from diode detector CR1 of shf drive assembly A2 which
select a signal from any of the four channel couplers or
is proportional to the rf drive power present at the input
from the shf output coupler A6DC2. The coaxial switch
of the amplifier- mixer. This channel of the comparator
is controlled by manual operation of front panel channel
will inhibit the FAULT lamp when rf drive is not present.
select switch S3. Front panel SHF MONITOR meter M1
g. Transient suppressor assembly A4 mounts
has full- scale markings of 15 milliwatts and 11.8 dbm.
the miscellaneous components used in the amplifier-
Three power ranges (X10, X1, and X0.1) are selected by
mixer.
front panel SHF MONITOR meter switch S1. The meter
h. Power supply PS1 furnishes +15 vdc and -
switch also has a CAL (calibrate) position which permits
zeroing of the SHF MONITOR meter by front panel CAL
15vdc to thermoelectric power monitor assembly A7 and
ZERO control R1.
rf low power alarm assembly A5. A second identical
f.
Rf low power alarm assembly A5, with
power supply (PS2) provides +30 vdc for operation of
coaxial selector switch A1Si. The + 15 vdc, -15 vdc,
adjustable threshold, alerts the operator in the event that
and +30 vdc voltages, as well as intermediate power
rf output level falls below a preset level. The rf low
amplifier (ipa) current, may be selected by front panel
power alarm assembly includes a dual channel
STATUS MONITOR meter switch for monitoring on the
comparator. One channel of the comparator accepts an
STATUS MONITOR meter.
analog signal from diode detector CR1 of shf output
assembly A6.
This signal is compared with an
adjustable threshold which is preset by poten-
Section III. DETAILED ANALYSIS
2-5.
General
coax switch S1 (c below). The level of the sampled
A detailed analysis of each assembly comprising the
input power fed to coax switch S1 is controlled by AT2,
amplifier-mixer is given in paragraphs 2-6 through 2-13.
which is a manually adjustable attenuator.
b. Power combiner DC1 combines the shf
The overall schematic diagram for the amplifier-mixer is
shown in figure FO-2.
input signals from the four shf channel assemblies
(A1A1thru A1A4). The combiner provides at least 18-db
2-6.
Shf Combiner Assembly A1
isolation between channels and each shf channel
assembly adds at least 40 db of reverse isolation,
providing 58-db minimum isolation between input
signals. The combined signal output from shf combiner
Shf combiner assembly A1 consists of four identical shf
assembly Al is fed to shf drive assembly A2 (para 2-' 7).
channel assemblies (A1A1 thru A1A4, power combiner
c. Coax switch S1 is a single pole, five-throw
DC1, and coax switch S1). These items are described
in a, b, and c below.
coaxial switch which is used to select a sample of the
four input signals (CH1-CH4) or the shf output signal for
application to thermoelectric power monitor assembly
a. Each of the four 7900-to 8400-MHz shf
A7 (para 2-12). The coax switch requires +30 vdc for
signals connected to front panel SHF CHANNEL
operation. This voltage is applied to the appropriate
COMBINER INPUT connectors CH1-CH4 are applied to
section of the switch by the front panel channel select
one of four shf channel assemblies, A1A1 through
switch.
A1A4. In the shf channel assembly, the input shf signal
passes through input isolator HY1, variable attenuator
2-7.
Shf Drive Assembly A2
AT1, directional coupler DC1, and output isolator HY2 to
power combiner DC1 (b below). The level of the signal
fed to DC1 is con- trolled by variable attenuator AT1,
which is manually adjusted by the front panel CH1-CH4
Shf drive assembly A2 consists of isolator HY1,
LEVEL ADJUST controls. The 10-db directional coupler
directional coupler DC1, diode detector CR1, gain set
(DC1) samples the input power for application to
attenuator AT1, output level adjust attenuator A2, and a
thermoelectric power monitor assembly A7 (para 2-12)
fixed output attenuator (AT3). The combined shf signal
via
variable
attenuator
AT2
and
2-2
