
5-4
GTX 327 MAINTENANCE MANUAL
Rev B
190-00187-05
5.7.1
ATC-1400A and Oscilloscope Default Settings
Configure the ATC-1400A switches as shown in Figure 3-1.
•
Set RF Level to –50 dBm
•
Set XPDR MODE switch to position A
•
Set PRF to 500 Hz
•
Turn SLS to OFF
Set the Oscilloscope to the following initial settings:
•
EXT TRIG (Sync to ATC-1400A)
•
CH 1 VERTICAL SENS 20 mV/Div
•
HORIZONTAL SWEEP 100 ns
•
DELAYED SWEEP center on first pulse
5.8
STANDARD TEST SIGNALS
5.8.1
Input Voltages
Unless otherwise specified, all tests will be performed with power input voltages and RF signal as follows:
•
GTX 327 DC power input voltage per aircraft system of 13.75 Vdc or +27.5 Vdc. Note that
the GTX 327 will operate on any DC voltage b11 and +33 Vdc.
•
GTX 327 Panel Lighting input per aircraft voltage with unit configured accordingly.
5.8.2
RF I/O
The standard input test signal shall be 1090 MHz at –50 dBm with the PRF set to 500 Hz. The XPDR mode
switch on the ATC-1400A must be either in mode A or C. Set the ATC-1400A RF Level to –50 dBm except for
tests necessary to measure MTL, Dynamic Range or SLS performance.
5.9
POWER ON CHECK
Adjust the power supply voltages before connecting the unit. Verify that the GTX 327 has been correctly
configured for the Panel Lighting voltage that will be used in the aircraft. Refer to the GTX 327 Installation
Manual, 190-00187-02, for details.
1.
Set the main power supply voltage to +27.5 Vdc or the actual aircraft voltage.
2.
Set the panel lighting supply voltage as appropriate for the aircraft and apply this voltage to J3271
pin 23 or pin 24 through the test harness as specified in Figure 2-3.
3.
Connect the GTX 327 to the Test Harness along with the RF coax connection and apply DC power.
4.
Turn on the GTX 327 and complete the following tests:
The document reference is online, please check the correspondence between the online documentation and the printed version.