Nokia 6600 Rf Troubleshooting And Manual Tuning Manual page 33

NHL-10
RF Troubleshooting
The spectrum analyzer screen should now look similar to that of the figure below (GSM900
case).
Figure 4: Spectrum analyzer screen shot when performing IQ tuning
Ref Lvl Ref Lvl
35 dBm 35 dBm
35
27.5 dB Offset
30
20
10
0
-10
-20
-30
-40
-50
-60
-65
Center 897.4 MHz
Date: 14.JAN.2002
The purpose of this tuning is to reduce the frequency components at marker 2 (carrier leakage)
and marker 3 (+67kHz / upper sideband) as much as possible. 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, the carrier (marker 2) should be at least 40dB below
the lower side band (marker 1).
Next, 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.
ISSUE 2 01/2004
Marker 1 [T1]
33.35 dBm
897.33229000 MHz
1
30 kHz/
13:11:55
COMPANY CONFIDENTIAL
Copyright © 2003 Nokia. All Rights Reserved.
CCS Technical Documentation
RBW 3 kHz
VBW 3 kHz
SWT 3 s
1 [T1]
2 [T1]
3 [T1]
2
3
RF Att 30 dB
Unit dBm
33.35 dBm
A
897.33229000 MHz
-6.76 dBm
897.40000000 MHz
-10.74 dBm
897.46771000 MHz
1MA
Span 300 kHz
33