Egsm (Egsm900) Transmitter; General Instructions For Egsm Tx Troubleshooting - Nokia 616 Service Manual

TFE-4/RV-1
TF4 Technical Information
• Two PREGAIN amplifiers, one for EGSM900 and one for GSM1800.
• Two passive I/Q mixers (MIX), one for EGSM900 and one for GSM1800.
The resulting BB signal is further amplified in the BB chain. For this purpose no external
circuitry is required:
• Base band amplifiers (BBAMP1). That amplifiers implement the initial channel
filtering.
• Low pass filters (LPF1).
• DC compensation / AGC amplifiers (DCN1). They implement gain steps from 0dB
to 24dB in 6dB steps.
• Attenuators (AGC). They implement gain steps from -48dB to 0dB in 6dB steps,
yielding a total gain range of 72dB together with DCN1.
• Bi-quad filters (LPF2).
• DC compensation amplifiers (DCN2).
The differential base band outputs are internally DC coupled and can be connected
directly to the ADC inputs of the RF converter chip. The common mode level is set equal
to the VBEXT reference voltage.

EGSM (EGSM900) Transmitter

General instructions for EGSM TX troubleshooting

Apply a RF-cable to the RF-connector and connected to the measurement equipment
(GSM Test equipment, Powermeter, Spectrum Analyzer, or similar). Be sure to use at least
a 10dB attenuator, otherwise the results may be incorrect.
Step 1: Setting up Phone and Phoenix
• Start Phoenix Service Software
• Open the FBUS connection
• Select File /Scan Product (Ctrl-R)
• Wait until phone information shows in the lower right corner of the screen.
• Set operating mode to local mode
• Activate RF-Controls
• Select Maintenance/ Testing/ RF Controls. Wait until the RF Controls window
pops up
• Select:
Page 8b-54
Company Confidential
Band
Active unit
Operation mode
RX/TX Channel
TX PA Mode
TX Power Level
TX Data Type
Copyright © 2005 Nokia Corporation.
Company Confidential
Nokia Customer Care
GSM 900
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Issue 2.0 Mar/2005