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Shyam Telecom Limited Page
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Next Generation
Signal Enhancement
a. DONOR Antenna
Donor antenna of appropriate bandwidth & gain interfaces the BTS on
one side and repeater system on other side through RF cable.
Figure 10: Donor Antenna (Patch Panel)
It receives signals from the base station and transforms electromagnetic
waves into RF signals in the DL and vice versa in the UL. The antenna
with more than 10-12 dB gain transfers received signals to the repeater
and transmits uplink signals amplified by the repeater.
b. Duplexer
The main function of
duplexer
is to isolate the uplink frequency from the
downlink frequency, i.e. isolate transmit path from receive path. Two
duplexer units are provided in the repeater, one in the Donor antenna
side and other in the server antenna side. Each duplexer
transfers/receives signals from respective antenna for further connectivity
to low noise amplifier. The bandwidth of the duplex filter
depends on the
operator’s frequency band
(25MHz, 15MHz, 10MHz, 9MHz, or full
Band etc.).
c. Low Noise Amplifier (LNA)
This module is provided after duplexer before the converter. The
LNA
provides compensation for the losses suffered by the stream of weak
signals as it passes through splitter/combiner & duplexer (passive
devices). Two LNAs are provided, one each in the UL & DL directions.
d. Converter Module
The basic block of
converter
module comprises of L.O., frequency mixer,
filter and intermediate amplifier. The low noise amplified signals are
converted to IF in frequency mixer with frequency fed from LO. The
