Gsm Rx Chain Activation For Manual Measurements/Gsm Rssi Measurement - Nokia RM-579 Service Manual

RM-578; RM-579
RF troubleshooting
The main RX troubleshooting measurement is RSSI reading. This test measures the signal strength of the
received signal. For GSM RSSI measurements, see
RSSI measurement .

GSM RX chain activation for manual measurements/GSM RSSI measurement

Prerequisites
Make the following settings in Phoenix service software and in the signal generator:
Setting
Phoenix Channel
Signal generator
to antenna
connector
Steps
1. Set the phone to local mode.
2. Activate RSSI reading in Phoenix (Testing→GSM→RSSI reading )
Results
Measuring mode set to Sum vector , the reading should reflect the level of the signal generator (-
With the
losses) +/- 5 dB.
When varying the level in the range -30 to -102 dBm the reading should then follow within +/-5 dB.
Now select the measuring mode to
the signal generator level.
Next actions
RSSI-reading AND TX troubleshooting is failing: replace N7520.
TX is OK and RX is failing: replace N7505.
Issue 3
GSM850
190
881.66771 MHz
(67.71kHz offset)
at -60dBm
Q branch and I Branch . In each case the reading should be 3 dB below
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GSM RX chain activation for manual measurements/GSM
GSM900
37
942.46771 MHz
(67.71kHz offset)
at -60dBm
GSM1800
700
1842.86771 MHz
(67.71kHz offset)
at -60dBm
GSM1900
661
1960.06771 MHz
(67.71kHz offset)
at -60dBm
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