Fig 12 Receiver Fault Chart 1 - Nokia NPL-4 Series Troubleshooting Instructions

NPL-4/5/RM-104
Troubleshooting Instructions
- Check if AGC calibration is within limits
- Check if SNR reading is OK.
- Use an Oscilloscope to check levels of "RXI" and "RXQ".
The RF ASIC generates only single ended I and Q signals (RXI, RXQ). As the A/D converter
in UEM requires two differential signals, an artificial mid voltage is generated from
VrefRF02.
The BB part is used to measure those signals by means of RSSI reading. This works only if
correct calibration has been carried out in production.
RSSIreading [dBm] = 20log(U
If both RX and TX path seem to be faulty it has to be checked if the synthesizer is work-
ing.
Make sure that
Synthesizer is working
Yes
All 3 bands
Phoenix:
Phone:
Open RF Controls:
Active Unit:
Op. Mode:
Rx/Tx channel:
Signal Generator:
Level:
Frequency:
Phoenix:
Open RSSI reading
Check RSSI Level = -80dBm
No
Execute Rx Calibration in selected
band
Are calibration results within limits?
No
Are all 3 bands measured?
Yes
Copyright © 2005 Nokia Corporation. All rights reserved.
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Company confidential
/U
BB LSB
Figure 12: Receiver Fault Chart 1
No
local mode
Rx
Burst
default (mid)
–80dBm
calculated from
Phoenix + 67.71kHz
Yes
Yes
No
) - AGC
calibrated
see
Synthesizer Fault
Finding Tree
Selected band is working and
calibrated.
Are all 3 bands measured?
Yes
Rx chain is functional
and calibrated
Nokia Customer Care
Receiver
Fault Chart 1.
No Next band
Issue 2 05/05