Nokia 301 Service Manual page 173

RM-839; RM-840; RM-841
System Module
• Antenna
The TX features 5 RF outputs, 2 outputs are high power, small signal polar modulated outputs for the GSM
system, with low sensitivity to PA harmonics. The low band output covers the 850 and the 900 MHz GSM
bands, the mid band output covers the 1800 and 1900 MHz bands.
The UMTS outputs are vector modulated single ended high power driver amplifiers, with excellent EVM and
adjacent channel leakage performance. Together with external UMTS power amplifier modules the bands I,
II, V and VIII can be addressed. There is one driver for all low bands (850 and 900 MHz bands), one driver for
the mid band (1700 - 1900 MHz bands) and one driver for the high band (2100 MHz band).
For transmitter section, the modulated signal first is filtered to suppress the spurs out of working band, and
then gets amplification by the Pas, GSM PAs are integrated in FEM while 3G PAs are discrete. Some output
energy of 3G PAs will be feed back to the transceiver after rectification by the power detector for reporting
the power level of the output RF signal to the transceiver.
Issue 1 NOKIA INTERNAL USE ONLY Page 6 – 35
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