Receiver Troubleshooting; Introduction To Receiver (Rx) Troubleshooting; Gsm Rx Chain Activation For Manual Measurements/Gsm Rssi Measurement - Nokia N900 Service Manual

RX-51
Cellular RF troubleshooting

Receiver troubleshooting

Introduction to receiver (RX) troubleshooting

RX can be tested by making a phone call or in local mode. For the local mode testing, use Phoenix service
software.
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 . For a similar test in WCDMA mode, see WCDMA RSSI measurement .

GSM RX chain activation for manual measurements/GSM RSSI measurement

Prerequisites
Make the following settings in Phoenix service software:
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
The reading should reflect the level of the signal generator (-losses) +/- 5 dB.
When varying the level in the range -30 to -102 dBm the reading should then follow within +/-5 dB.
Issue 1
GSM850
190 37
881.66771MHz 942.46771MHz
(67.71kHz offset) (67.71kHz offset)
at -60dBm at -60dBm
Figure 26 Phoenix GSM RSSI reading window
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Copyright © 2009 Nokia. All rights reserved.
GSM RX chain activation for manual measurements/GSM
GSM900 GSM1800
700
1842.86771MHz
(67.71kHz offset)
at -60dBm
GSM1900
661
1960.06771MHz
(67.71kHz offset)
at -60dBm
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