Comtech EF Data LTT1450G - Manual (Page 21)

LTT1450G Ku-Band Loop Test Translator Operation
TM063 - Rev. 1 Page 3-3
Menu Pushbutton The menu pushbutton scrolls the translator through the status and calibration menus.
This will be discussed in detail in the troubleshooting section.
3.3 Rear Panel Connectors and Adjustments
3.3.1 Tx and Rx RF I/O
For Model LTT1450G translators, the TX and RX RF input and output ports are as follows:
Input Output
Ku-Band J1 J2
3.3.2 REF IN
This BNC-type connector allows the operator to inject either a 5 or 10 MHz reference signal for the
purpose of synchronizing the translator to an external reference. The signal to be injected should be 50
ohm, AC or DC coupled, TTL in the range of 0 to +10 dBm. It is not required to indicate to the translator
whether the signal is 5 or 10 MHz, as the microcontroller will determine the frequency of the external
reference. When a signal is injected at the REF in port, the front panel EXT REF LED will light to
indicate that an external reference signal was detected. If the EXT REF light lights and the LO FAULT
LED is not lit, the translator has synchronized the selected bands local oscillator to the external
reference. When an external reference is detected, the microcontroller shuts off the internal 5 MHz
VCXO. If a proper reference is not present, then an LO fault in the 25 MHz PLO of the selected bands
LO will be indicated.
3.3.3 REF OUT
The REF OUT BNC connector contains the 5 MHz reference currently being used to synchronize the
selected bands LO. If an external reference is not present, this port is the internal 5.00 MHz reference. If
an external 5 or 10 MHz reference is present on J4, then J5 will be the external reference loop out of the
translator. If the external reference is 10 MHz, J5 will contain that reference divided by 2 or once again 5
MHz
3.3.4 Test Fault (J5)
The dB 9-pin connector contains summary fault form-C contact and phase lock loop voltages for the six
phase-lock loops found in the translator.
The pinout of this connector is as follows:
Pin # Signal
1 Summary Fault common
2 Summary Fault N.O.
3 Summary Fault N.C.
4 GND