Description
2-35
1
2
3
4
5
RF amplification
This function receives the RF signal to be transmitted from the TRX function and takes its
level of + 12 dBm to a regulated output level of + 33.5 dBm, + 37.5 dBm, + 41.5 dBm or
+ 43.5 dBm. The output level is controlled by the synchronisation board.
The RF amplification function consists of:
• a variable attenuator, controlled by the slaving function, for controlling the output power,
• several amplification stages, controlled by the slaving function,
• a coupler for testing the RF signal on output ("RF TEST" socket),
• detectors sending information to the slaving function (levels, SWR) and to the alarm
function (temperature, power).
The amplified signal is then sent to the insulator via the "RF OUT" socket on the module.
Power slaving
This function carries out the power slaving of the RF amplification chain in order to supply a
regulated level on four stages.
The signals sent to the RF amplification function control:
• the variable attenuator,
• the amplification stages.
These signals are produced using:
• power and carrier commands (PA-ON) delivered by the SP function,
• information (level, SWR) detected by the amplification chain.
Monitoring
Using the information supplied by the various detectors in the module, the monitoring
function:
• transmits alarms to the control and configuration web interface:
- temperature alarm if the temperature inside the 3G PA-TRX module e 82
°
C
(the alarm disappears if the temperature drops below + 74
°
C),
- power alarm,
and lights up the "DEF" LED on the front of the 3G PA-TRX module,
• carries out module self-protective actions:
- switches to reduced power (+ 35 dBm) if the SWR on the module output exceeds 3
(returns to initial power level automatically when the SWR drops below 2),
- switches off the module if the temperature r 87
°
C (resets automatically
when the temperature drops below + 79
°
C again).
