User Manual

Band Selective Compact Repeater Block Diagram
Figure 5-3 shows a block diagram of the band selective compact repeater.
This diagram is applicable to repeaters for e.g. NMT, TACS/ETACS and
AMPS/DAMPS systems.
Downlink signal path
The signal from the base station is received via the repeater BS antenna
and is forwarded through a combiner (CMB) to the ANT input of a duplex
filter (DPX). The signal from the LO output of the duplex filter is, via
the P126 port, fed to the BSC board. On the BSC board, the signal is
amplified in a low noise amplifier (LNA) and is then entered the band
selective amplifier circuitry.
The first mixer stage in the BSC amplifier, which is controlled by a
synthesizer, converts the received frequency down to the IF frequency.
The signal is then filtered by a SAW bandpass filter and, not shown in the
RCC
BSC - UL
PA
LNA
P121
P122
BSC - DL
PA
LNA
P126 P128
P130
P112 P119
P130
DPX
MS
P118
BSC - CU
P124
CMB
BS
ANT
HI
LO
HI
LO
ANT
DPX
BS
MSC
PSM
BAND SELECTIVE COMPACT REPEATER
BS
antenna
Base station
Telephone line
Modem
Modem
Battery
External alarm sensors
MS
antenna
Figure 5-3. Block diagram
Functional Description ALR Compact Repeater ALLGON Systems AB
5 - 6 Rev. P1D 2000-05 VD203 67/EN - User’s Manual