User Guide

PAMS
System Module DB6
NHB–3
Technical Documentation
Original 26/97
Page 4–39
RF Blocks
Technical Summary
The RF module carries out all the RF functions of the transceiver. This module
works in the DCS1900 system .
The RF module is constructed on a 1.0 mm thick FR4 six–layer Printed Wire
Board.
Components are located on both sides of the PWB. All components with height
less than 2 mm are on side one and higher components are on side two.
EMC leakage is prevented with metallized plastic shield A on side one and
magnesium shield B on side two. Shield B conducts also heat out of the inner
parts of the phone thus preventing excessive temperature rise.
Technical Specification
RF Frequency Plan
VCXO
26 MHz
LO 2
PLL
LO 1
1st IF 2nd IF
13
f
f/2
f
f/2
f
f/2
CRFRT1930–
1990 313 87
3rd IF
100
400
200
RX:
1617–1677
TX:
1650–1710
1850–
1910
400
Maximum Ratings
The maximum battery voltage during the transmission should not exceed 8.5 V.
Higher battery voltages may destroy the power amplifier. This will be qua-
ranteed by hardware based limiting which has maximum value 7.6 ±0.3 V.
Power Distribution
All currents in the power distribution diagram are peak currents. Activity per-
centages are in SPEECH–mode 24.6 % for RXPWR , 15.8 % for TXPWR and