M900/M1800 BTS3X Series Base Transceiver Station
Hardware Description Manual
3 Board
Issue 01 (2006-11-18)
Huawei Technologies Proprietary
3-23
!
Use only the settings described in
.
!
Huawei recommends that MAIN and DIVERSITY be set to 100 mA and 200 mA respectively.
3.6 EDU
3.6.1 Functions
The EDU is designed for wide coverage and low loss.
It realizes the following functions:
!
Combining and filtering of transceiving duplex and transmitting signals
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Filtering of receiving signals
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Low-noise amplification
!
Dividing of receiving signals for TRXs
It also provides the TMA feeding. Each TRX uses independent antenna. The transmitting
combiner is unnecessary. The receiving mode is 1-into-2.
The EDU supports the following frequency bands:
!
GSM900
!
GSM1800
!
GSM1900
The maximum input power of its single port is 100 W.
3.6.2 Structure and Principle
The EDU has multiple panel types, but the structure and the principle of the EDU are the
same in any cases. For details, see
Figure 3-17
EDU structure
TA
feeder
Divider
Duplexer
Alarm and control
unit
Transmitting
input
Receiving
output
Low noise
amplifier
EDU
Test
coupler
TA
feeder
Divider
Duplexer
Receiving
output
Transmitting
input
Low noise
amplifier
Test
coupler