Nokia 6260 RM-25 Service Manual page 203

RM-25
RF troubleshooting
Figure 132 Spectrum analyzer screen shot when performing IQ tuning, part 1
5. Adjust the 'TXI DC Offset' and the 'TXQ DC Offset' buttons in the TX IQ Tuning window so that the carrier level
(marker 2) reaches a minimum.
After this adjustment is done, the carrier (marker 2) should be at least 40dB below the lower side band
(marker 1).
6. Use the 'Amplitude difference' and the 'Phase difference' buttons in the TX IQ Tuning window to adjust the
upper side band (marker 3) to a minimum.
Now, marker 3 should also be at least 40dB below marker 1.
At this point, the spectrum analyzer screen should look similar to that of the figure below.
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