User's Manual

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.
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.
229 | Radio Frequency Distribution System
6802800U74-AD | September 2014 |
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Applicant: Motorola Solutions
Equipment Type: ABZ89FC5827 / 109AB-5827
Exhibit D2