User's Manual Part 2

CL1TC-4 400W DVB-H Transmitter Alarms
Product Manual, Rev. 1 128
NOTE: The transmitter output is automatically muted as a result. Transmission is restored
when the alarm is cleared.
10.4 GPS Alarms
Pl
ease note that the internal GPS receiver is located on the modulator board.
10.4.1 GPS Comm Error
GPS Comm
Error - set when communications with the GPS receiver has failed.
10.4.2 GPS Antenna Undercurrent
GPS An
tenna Undercurrent – set when the antenna current value is low (antenna open).
10.4.3 GPS Antenna Overcurrent
GPS An
tenna Overcurrent – set when the antenna current value is high (antenna short).
10.4.4 GPS Quality Low
GP
S Quality Low – set by the internal GPS when the quality of the received GPS signals fall
below a minimum reception level or the number of available satellite is too low. The event
that contributes to a GPS Quality Low alarm is:
• PLL Status Unlocked
But, the GPS Quality Low alarm is only triggered when the GPS Max Holdover Time expires.
Once a PLL Status Unlocked event occurs, the GPS reference signals will be considered to be
in “Holdover” mode and the Holdover time counter begins. Once the Max Holdover Time is
exceeded the system controller will declare a GPS Quality Low alarm.
A PLL (Phase Locked Loop) Status Unlocked event can be the result of an antenna under-
current (antenna open) or antenna over-current (short), a poor GPS 3D Fix (minimum
requirement is 4 satellites). In general, conditions that result in a poor GPS signal quality.
Note: The GPS alarm is set at the system start-up and will be reset when the GPS receiver
obtains a 3D fix (4 satellites tracked).
Note: The GPS PLL Status and 3D Fix Status can be viewed from the Web-GUI interface;
from the Status drop down menu select GPS Status.
Note: It is recommended that the user set the modulator to mute on this alarm in SFN or
MFN mode.