Gsm Transmitter Tunings; Tx Iq Tuning (Gsm) - Nokia RM-42 Service Manual

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RM-42
RF Troubleshooting and Manual Tuning Guide
9.
Check that RSSI level value is between the limits presented in this table. If not, try clicking the Tune button
again.
Band
GSM900
GSM1800
GSM1900
10. Make sure that the "Save to Phone" check box is checked and click Stop.
Next action
Repeat steps 3 to 7 for GSM1800 and GSM1900.

GSM transmitter tunings

Tx IQ tuning (GSM)

Context
The Tx path branches to I and Q signals at RF I/Q modulator. Modulator and analog hardware located after it
cause unequal amplitude and phase disturbance to I and Q signal paths. Tx IQ tuning tuning balances the I and
Q branches.
Tx IQ tuning must be performed on all GSM bands. GSM1900 uses the same values as GSM1800.
Steps
1. From the dropdown menus, set "Operating mode" to Local, "System mode" to GSM, and Band to GSM900.
2. From the Tuning menu, choose GSM -> Tx IQ Tuning.
3. Set Mode to Automatic and Edge to Off.
4. Click Start.
Wait until automatic tuning has finished and moved the sliders.
Values are written to the phone memory automatically.
9241872 (Issue 1)
Table 15 RSSI level values
Min
-115
-115
-115
Company Confidential
Copyright ©2005 Nokia. All Rights Reserved.
Nokia Customer Care
Max
-90
-85
-100
Unit
dB
dB
dB
Page 7–37

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