Tx Power Level Tuning (Gsm) - Nokia RM-235 Service Manual

RM-235
RF troubleshooting
I DC offset / Q DC
offset
Ampl
Phase
GSM1800/GSM1900
I/Q DC
Ampl
Phase

Tx power level tuning (GSM)

Context
Because of variations at the IC (Integrated Circuit) process and discrete component values, the actual
transmitter RF gain of each phone is different. Tx power level tuning is used to find out mapping factors
called 'power coefficients'. These adjust the GSM transmitter output power to fulfill the specifications.
For EDGE transmission, the bias settings of the GSM PA are adjusted in order to improve linearity. This affects
the PA gain and hence the power levels have to be aligned separately for EDGE transmission.
Tx power level tuning has to be performed on all GSM bands.
Steps
1. Connect the phone to a spectrum analyzer.
Phoenix service software.
2. Start
3. From the Operating mode drop-down menu, set mode to Local.
4. Choose Tuning→GSM→Tx Power Level Tuning .
Issue 1
Min
-6
-1
85
-6
-1
95
COMPANY CONFIDENTIAL
Copyright © 2008 Nokia. All rights reserved.
Typ
-4
0
90
0.5
0
100
Max
6
1
95
6
1
110
Unit
%
dB
°
%
dB
°
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