Table of Contents
Advertisement
Chapter 7
Radio Frequency Distribution System
The Radio Frequency Distribution System (RFDS) distributes and manages the communications
network frequencies and mitigates interference between multiple radios, allowing them to operate
simultaneously. This results in improved radio reception performance across the frequency ranges
where multiple transmitters are broadcasting.
7.1
RFDS Theory of Operation
The RFDS module is made up of the following subcomponents:
•
Preselector (MTS LiTE, MTS 2, and MTS 4)
•
Duplexer (MTS LiTE, MTS 2, and MTS 4)
•
Cavity Combiners (MTS 4 and Expansion Cabinet)
•
Hybrid Combiner (MTS 2, MTS 4 uses either HC or CC)
•
Post Filter (MTS 4 only)
•
RX Splitter (Expansion Cabinet only)
The RFDS module supports the combining and filtering of multiple Base Radio transmitters to one or
more antenna outputs. The RFDS module supports up to triple receive diversity. Signals are filtered by
either the Duplexer or the Preselector, then amplified and distributed by the integrated Receiver
Multicoupler (RMC). In configurations with an Expansion Cabinet, the RX-splitter is used to distribute
the received signal.
The RFDS also conditions the transmit and receive signal using filters. After combining the Base Radio
transmitters in the Hybrid Combiner (or in the Cavity Combiner in the case of the MTS 4), the transmit
signals are filtered in the transmit path of the Duplexer, which supplies the antenna connector on the
cabinet.
MTS LiTE, MTS 2 and MTS 4, with or without Expansion Cabinet configuration, use different types of
RFDS modules. The following are the distinct differences:
•
MTS 2 supports Hybrid Combiners
•
MTS 4 supports Cavity Combiners or Hybrid Combiners
•
MTS LiTE/MTS 2 and MTS 4 do not use the same filters and mechanics for the filter tray
•
MTS LiTE support one RF channel
•
MTS 2 supports up to two RF channels
•
MTS 4 supports up to four RF channels
•
Expansion Cabinet supports eight RF channels (four in MTS 4 Prime Cabinet and four in MTS 4
Expansion Cabinet)
MTS 2 only has up to two carriers (the frequency that it sends out) and, as a result there are no Post
Filters for a non-duplexed operation. A non-duplexed operation is achieved using a Duplexer as the
Post Filter and not using the receive path of the Duplexer. This configuration does not allow room for a
third Preselector inside the cabinet; however, it is possible to situate one outside the cabinet, for
example, on the wall.
6802800U74-AN
Radio Frequency Distribution System
257
Hide quick links:
Advertisement
Table of Contents
Troubleshooting
