Rx Paths Of Mjoelner Rf Asic - Nokia RH-47 Series Rf Description And Troubleshooting

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RX paths of Mjoelner RF ASIC

The balanced RX signal is amplified by the integrated LNA and the subsequent pre-gain
stage. After amplification the RX signal is down-converted.
The RX paths of Mjoelner RF ASIC consist of following sub units:
Separate LNAs for each of the two bands: GSM850 and GSM1900.
Two PRE-GAIN amplifiers, one for GSM850 and one for GSM1900.
Two passive I/Q mixers (MIX), one for GSM850 and one for GSM1900.
The BB signal paths consist of:
• Baseband amplifiers (BBAMP1). These amplifiers implement the initial channel
filtering.
• Low pass filters (LPF1).
• DC compensation / AGC amplifiers (DCN1). These amplifiers 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 are connected directly
to the ADC inputs of the UEM-ASIC. The common mode level is set equal to the VBEXT
reference voltage.
Issue 1 05/04
Company Confidential
7 - RF Description and Troubleshooting
Copyright © 2004 Nokia Corporation
Company Confidential
RH-47
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