Nokia Mobile Phones NSE-5 Series Service Manual page 144

NSE–5
Service Software Instructions
The TX I/Q tuning is performed in the following 7 steps:
Connect the GSM/PCN signal tester or spectrum analyzer to
the phone antenna connector. When using spectrum
analyzer: The recommended spectrum analyzer settings are:
span 200 kHz, resolution bandwidth 10 kHz, video bandwidth 1
kHz, sweep 500 ms, input attenuation 30 dB.
Select PCN band on the GSM/PCN signal tester or GSM/PCN
Spectrum analyser. Select the PCN band in WinTesla in menu
Product, Band and PCN.
Select the menu Tuning and Tx I/Q.
Choose the option EEPROM values to tune the TX I/Q values
in the phone, and select OK.
Adjust the TX I DC Offset and TX Q DC Offset stepwise until
the carriers are suppressed as much as possible (Refer to the
drawing below). When tuning adjust the values slowly step by
step.
Adjust the Amplitude difference and the Phase difference
stepwise until the side bands are suppressed as much as
possible (Refer to the drawing above). When tuning adjust the
values slowly step by step.
Store the selected values to the phone by pressing OK.
Page 44
PAMS
Technical Documentation
Issue 1 07/99