Level 3 Service Manual
GALAXY ASTRAL GEO GEO WAP
Version E
Mitsubishi Electric Telecom Europe SA
Date: 04/00
ZA le Piquet 35370 Etrelles
Phone: +33 2 99 75 71 00
16/29
Fax: + 33 2 99 75 71 47
3.5.3
Power Control.
APCCNT is the reference waveform voltage for a TX burst (provided by IC300).
TX1SW : This control signal is used to switch on/off the preamplifiers. ( TR702 and TR712 )
H.Level : Pre Amp is active.
L.Level : Pre Amp is not active.
TX3SW :This control signal is used to switch on/off the operational amplifier of the APC Loop (IC710).
H. Level : Detecting Circuit and comparison Error AMP is active.
L. Level : Detecting Circuit and comparison Error AMP is not active.
RF signal is rectified by voltage doubler Schottky barrier diodes D700. This level is compared with
APCCNT. The result of the comparison is used to vary the gain of the HPA IC702.
The APCCNT signal input from the base band circuit (IC300) contains the burst shaping information
and the power level to be set among the 15 power levels defined by the GSM, or the 16 power levels
defined by the DCS specifications. It controls the output power level by a feed-back loop (Automatic
Power Control ).
E-GSM
DCS
PCL 5
→
+33 dBm
PCL 0
→
+30 dBm
PCL 19
→
+5 dBm
PCL15
→
+0 dBm