CCS Technical Documentation
Troubleshooting
RH-13
Issue 1 11/02
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Nokia Corporation
Page 71
- This tuning has to be done simultaneously with AFC-tuning
If LP and AMP2 filter tunings fail it may be due to:
- Problems with lower band signal path (synthesizer etc.)
- VCTCXO component can be broken
- Safari can be broken or solder joints
UB RX AGC tuning
- UB TDMA minimum gain (around 0 dB), measured when lna is switched off
- UB LNA gain step, measured when lna is switched on. Result is gain difference between
lna on and off (around 20 dB)
- If UB TDMA minimum gain is lower than -2 further analysis is needed. Result 32752
means that the signal doesn't go through RX chain at all or it has a lot of attenuation.
If it fails there can be following problems:
- Rx chain is totally deaf or some gain is missing, start receiver troubleshooting
LB RX AGC tuning
- LB TDMA minimum gain (around 2 dB), measured when lna is switched off
- LB LNA gain step, measured when lna is switched on. Result is gain difference between
lna on and off (around 20 dB)
- If LB TDMA minimum gain is lower than -2 dB, further analysis is needed. Result
32752 means that the signal doesn't go through RX chain at all or it has a lot of attenu-
ation.
If it fails there can be following problems:
- Rx chain is totally deaf or some gain is missing, start receiver troubleshooting
TDMA TX tunings
If some TX tunings fails, start always TX troubleshooting!
TX IQ (TxIq)
- Purpose of the tuning is to tune DC offset and phase offset so low as possible (test limit
–40 dBc)
If tuning fails there can be following problems: