Does The Phone Give Realistic Rssi-Values; Is Hinku Asic (N7500) Receiving Rf-Power Correctly From The Wcdma-Antenna Connector - Nokia RM-42 Service Manual

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4.1.3.3.2.3 Replace Retu
4.1.3.3.3 Replace VCTCXO G7501

4.2 Does the phone give realistic RSSI-values?

Attach the phone to the product specific test jig and a signal generator to the RF-coupler. Coupler
attenuation should be also taken into account during measurements.
Use the signal generator to supply -90 dBm RF-level to the phone via the antenna coupler. Set
generator RF-level to -90 dBm + Cable and coupler attenuation. This measurement should be
performed in a RF-shielded environment because existing WCDMA-network base stations can disturb
this measurement otherwise.
• Set RF-generator frequency to 2141.0 MHz (unmodulated signal).
• Use Phoenix testing & tuning software to perform WCDMA receiver activation and RSSI
measurement for channel 10700. Procedure is explained in sections "WCDMA RX chain activation
for manual measurement" and "WCDMA RSSI measurement".
• "Rx Power Measurement" tool should show quite exact -90 dBm RSSI level. Remember to take into
account attenuation between the phone and signal generator.
Increase signal generator RF level to -60 dBm. Phoenix "Rx Power Measurement" tool should show
•
now quite exact RSSI level -60 dBm.
• If RSSI-levels are not as expected separate the phone into parts and place to the module jig.
Connect the signal generator to the module jig WCDMA RF connector (Notice that there are three
antenna connectors in the module jig, one for GSM, one for WCDMA and one for Bluetooth. Make sure
that all connections are made to the correct RF-connector).

4.2.1 Is Hinku ASIC (N7500) receiving RF-power correctly from the WCDMA-antenna connector?

WCDMA receiver has to be active before measurements. Procedure is explained in section
•
"Receiver troubleshooting".
• Connect an RF-generator to the WCDMA-antenna connector
• Set RF-generator frequency to 2141.0 MHz (unmodulated signal)
• Measurements can be done with a spectrum analyser and an RF probe. Remember to make correct
frequency settings to the spectrum analyser (Centre frequency should be set to the same
frequency as the RF-generator). RBW = VBW = 10 kHz, Span = 0, sweep time = 100 ms.
• Connect the probe to T7500 output. There are two output pins because of balanced output. The RF
level should be roughly -85...-90 dBm in both output pads when input signal level in WCDMA
antenna connector is -50 dBm.
4.2.1.1 Does duplex-filter (Z7502) work properly?
• WCDMA receiver has to be active before measurements. Procedure is explained in section
A-98
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Appendix A: RF Troubleshooting