TM 11-6625-2398-15-2
dials always rotate at a 36: 1 ratio. Gear train 1A1A1A13
5-6. Test Points
is mechanically coupled to synchro 1A1A1A13B3 and
(fig. 6-1)
resolver 1A1A1A13B1.
Monitoring of the IFF set video and adjusted IFF azimuth
c. Azimuth Data. When FREQ SELECT switch
signals can be accomplished from test points on the front
1A1A1S5 is set to either 60 Hz or 400 Hz, primary power
panel of interface adapter unit 1A1A1. The following is a
is coupled from the contacts of relay 1A1A1K1 50 the
listing of the test points and the signal available for
rotor of synchro 1A1A1A3B3 and to rear panel jack
monitoring:
1A1A1J6. The output of synchro 1A1A1A13B3 will
Interface adapter unit
depend on the degree of displacement that gear train
IFF signal
test point
1A1A1A13 has moved the rotor of synchro
Computer target start .................................... 1A1A1TP1
Computer target end .................................... 1A1A1TP2
1A1A1A13B3. The stator voltage of synchro
Computer target present ............................... 1A1A1TP3
1A1A1A13B3 is applied to ANT ROTATION switch
Computer true friend ..................................... 1A1A1TP4
1A1A1S3. The setting of this switch allows for
Undecoded mode C video ............................. 1A1A1TP5
clockwise, counterclockwise, or a stationary mode of
IFF zero time trigger ..................................... 1A1A1TP6
operation of the IFF set antenna.
Clockwise or
IFF display video .......................................... 1A1A1TP7
counterclockwise operation is accomplished by switching
Buffered receiver video ................................. 1A1A1TP8
stator S1 and S3 outputs. Stationary operation is
Adjusted IFF azimuth S1 .............................. 1A1A1TP9
accomplished when ANT ROTATION switch 1A1A1S3
Adjusted IFF azimuth S2 .............................. 1A1A1TP10
Adjusted IFF azimuth S3 ............................... 1A1A1TP11
is set to STA position. This provides an open circuit to
Adjusted IFF azimuth RI ............................... 1A1A1TP12
the IFF set antenna drive circuit, and keeps the IFF set
Adjusted IFF azimuth R2 ............................... 1A1A1TP13
antenna stationary. As the RPM CONTROL transformer
is varied, gear train 1A1A1A13 rotates the synchro rotor
5-7. Enables
so that the resultant stator output voltage drives the
(fig. 6-1)
antenna at any speed between 5 and 25 rpm. ANT
Front panel toggle switches on the interface adapter unit
ROTATION switch 1A1A1S3 couples the stator voltages
can be used to enable functions in the IFF set by
to rear panel jack 1A1A1J10 via the SYNC/RSLVR SEL
providing grounds when interface adapter unit 1A1A1 is
switch in the SYNC position. When the SYNC /
connected in a test-bed configuration. These functions
RSLVR SEL switch is set to RSLVR and the FREQ
and associated switches are listed below.
SELECT switch is set to 4000 Hz, primary ac power is
supplied to a 4 kHz
1A1A1U1 via
Function
Interface adapter unit switch
transformer 1A1A1T2. The 4 kHz generator 1A1A1U1 is
External sif on ............... EXT SIF switch 1A1A1S7
a nonrepairable assembly that accepts the primary ac
External mode 4 on ...... EXT M4 switch 1A1A1S8
power and provides a 4 kHz, 26 vrms output. This
SIF tail on ..................... SIF TAIL switch 1A1A1S9
output is supplied to resolver 1A1A1A13B1 through
External mode C on ...... EXT MODE C switch 1A1A1S10
contacts of FREQ SELECT switch 1A1A1S5. When the
External test target on ... EXT TEST TGT 1A1A1S11
4 kHz, 26 vrms is supplied to stator windings 1A1A
Trigger control on. ......... TRIG CONTROL switch 1A1A1S12
1A13B1-S1 and 1A1A1A13B1-S3, resolver 1A1A1A13B1
Inhibit gate ..................... INHIBIT GATE switch 1A1A1S13
operates similarly to synchro 1A1A1A13B3. Resolver
1A1A1A13B1 stator voltage is also supplied at rear panel
5-8. Hybrid Attenuator 2A1
jack
1A1A1J10
as
a
reference
voltage.
Counterclockwise operation of the IFF set antenna is
a. General. The hybrid attenuator contains two
accomplished when ANT ROTATION switch 1A1A1S3 is
subassemblies, hybrid coupler 2A1HY1 and variable
positioned at CCW.
This reverses resolver
attenuator 2A1AT1. The hybrid attenuator can be used
1A1A1A13B1-R2 and -R4 rotor outputs. The output of
separately to couple RF to or from the IFF set and
resolver 1A1A1A13B1 is supplied at rear panel jack
external test equipment, or it can be used alone as a
1A1A1J10.
Springloaded momentary ROTATION
variable attenuator. When the hybrid attenuator is used
ENABLE switch 1A1A1S2, provides power for rotation of
to couple RF, cable 2A1W3 connects attenuator 2A1AT1
the IFF set antenna when interface adapter unit 1A1A1 is
to hybrid coupler 2A1HY1. This permits up to 25 db
connected in a test-bed configuration.
ROTATION
attenuation of the difference channel RF below the sum
ENABLE ON indicator lamp 1A1A1DS2 lights to indicate
channel RF, when performing receiver testing of the IFF
the IFF set antenna drive circuits are being actuated
set.
by
ROTATION
ENABLES
switch
1A1A1S2.
b. Attenuator 2A1AT1. Attenuator 2A1AT1 is a
two-terminal,
nonrepairable,
wideband
variable
attenuator with direct reading dial. The dial is calibrated
5-2
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