TRAK MODEL 9100 MODULAR FREQUENCY/TIME SYSTEM
3-8
TM4400013
Rev
D
3-3 INITIALSYNCHRONIZATION
With all signal connections made, antenna(s) installed, connected and power applied, the Model 9100
automatically performs initial synchronization. No operator intervention is necessary other than setting the
antenna cable delay, if different than the factory setting of 65 nanoseconds. Antenna cable delay can be
changed through the RS-232 interface using the SDC command. Propagation delay for common cable type is
provided in Table 2 of Appendix E.
Warning: Connecting the antenna(s) to the Model 9100 after power is applied may cause the GPS
receiver to take longer than normal to acquire satellites. If power is applied without
antenna(s) connected for greater than 1-hour, it is recommended that power be cycled
to allow the GPS receiver to perform normal satellite search.
At power up and for 20 to 45 minutes, the system front panel LEDs provide indication of the initialization stages.
These are the sequence of events and that occur.
a. All Power Supply green LEDS should be illuminated.
b. All FSU LEDs illuminate for 5 seconds, then the AUTO LED remains on and all others off, indicating
initialization of the FSU is complete.
c. The GPS REF modules FAULT, ONLINE and STANDBY LED illuminate for 20 seconds, then the FAULT,
ON LINE, and STANDBY LEDS of the GPS REF modules go out, indicating CPU initialization of the GPS
REF modules is complete.
d. Once the GPS REF module is initialized the LOCKED LED flashes until the GPS receiver acquires
satellites, oscillator warm-up is complete, and 1 PPS phase is within
±
400 nanoseconds of the GPS 1 PPS.
The TRACKING LED will normally illuminates within 5 to 10 minutes after power up. The module is
operational when the LOCKED LED remains ON. This normally takes 20 to 45 minutes.
NOTE: While the LOCKED LED flashes the 1 PPS, 5 MPPS and Composite outputs of the GPS
REF module are muted. If redundant GPS REF modules are installed and the backup GPS
REF locks first it will be placed on line until the primary module locks.