User Guide

NSM–3
System Module
PAMS Technical Documentation
Page 37
Issue 1 12/1999
 Nokia Mobile Phones Ltd.
RF Module
This RF module takes care of all RF functions of EGSM/DCS1800 dual-
band engine. RF circuitry is located on one side of the 8 layer tranceiver–
PCB. PCB area for the RF circuitry is about 15 cm2. The RF design is
based on the first dualband direct conversion RF–IC ”Hagar”. So there is
no intermediate frequency and that means the number of component is
much lover than before and there shall be much less interference prob-
lems than previously.
EMC emissions are taken care of using metallized plactic shield, which
screens the whole transceiver. Internal screening is realized with isolated
partitions. At least the VCO is isolated. The baseband circuitry is located
on the same side of the same board.
Maximum Ratings
Parameter Rating
Battery voltage, idle mode 3.9 V
Regulated supply voltage 2.8 +/– 3% V
Voltage reference 1.5 +/– 1.5% V
Operating temperature range –10...+55 deg. C
Absolute maximum voltage 4.8 V
RF Characteristics
Item Values (EGSM / DCS1800)
Receive frequency range 925 ... 960 MHz / 1805 ... 1880 MHz
Transmit frequency range 880 ... 915 MHz / 1710 ... 1785 MHz
Duplex spacing 45 MHz / 95 MHz
Channel spacing 200 kHz
Number of RF channels 174 / 374
Power class 4 (EGSM900) / 1 (DCS1800)
Number of power levels 15 / 16