User Guide

NPL-4/5
System Module and User Interface Nokia Customer Care
Page 84 Copyright © 2004 Nokia Corporation. All rights reserved. Issue 1 05/04
Figure 40: Power Amplifier
RF ASIC Helgo
The RF ASIC module includes:
- TFBGA88
- Balanced I/Q demodulator and balanced I/Q modulator
- Power control operational amplifier, acts as an error amplifier
- The signal from VCO is balanced, frequencies 3296 to 3980 MHz
- GSM850/EGSM900 and GSM1800 low noise amplifier (LNA) are integrated.
The Helgo can be tested by test points only.
AFC function
AFC is used to lock the transceiver’s clock to the frequency of the base station.
Antenna
The NPL-4 (GSM850/GSM1800/GSM1900) and NPL-5 (EGSM900/GSM1800/GSM1900)
transceivers have their own internal antennas.
EGSM
out
DCS/
PCS
out
EGSM
in
DCS/
PCS
in
Power
detector
EGSM
Power
control
DCS/PCS
Power
control
Mode
EGSM900 GSM1800/1900
900900
GSM1800/1900 GSM1800/1900
GSM850/EGSM900
GSM850/EGSM900