DT-4500 Series C- and Ku-Band Down Converters
MN/DT4500.IOM
Introduction
Revision 2
1–3
1.2.1
Applications
The DT-4500 is a down converter. It converts the input RF frequency to an output
IF frequency. The DT-4500 operates over the RF frequency range with a typical
gain of 35 dB. The RF output level is +10 dBm @ 1 dB compression. This permits
longer cable runs and compensates for splitting networks without requiring
options such as external line amplifiers.
The phase noise performance exceeds the Intelsat phase noise mask for IBS and
IDR services by more than 9 dB. This allows high capacity earth stations to add
more demodulators and still meet transmission standards. The close-in phase
noise is also very low. This makes the converter ideal for low bit rate digital
circuits such as those used in DAMA hub earth stations.
Depending on the application, the converter chassis rear panel module slot
accepts an Input/Output Module (IOM), Polarity Switch Module (PSM), Transmit
Switch Module (TSM), Equalizer Module (EQM), or Receive Switch Module (RSM).
The converter RF, IF, and High-Speed Bus (HSB) connectors are integral to the
installed module.
Non-redundant (also called standalone or single thread) units employ an IOM for
switching the RF output. The IOM is also used for unit testing.
In redundancy applications, where converters are "Daisy Chained" to provide
distributed online protection switching to a backup converter (BU), a TSM is used
in place of an IOM. The TSM contains RF and IF transfer switches. Type ‘N’ female
connectors are provided for the RF loop, and 50
Ω
or 75
Ω
BNC female connectors
are provided for the IF loop.
The "Daisy Chain" configuration is designed to chain the IF output of up to twelve
(12) online converters through RSMs terminating in a BU. When a fault occurs in
an online converter, the RSM in the faulted converter is commanded to switch to
the BU.
The BU in the "Daisy Chain" communicates with the online converters through
the installed module’s High Speed Bus (HSB data interface). When faults are
detected, the BU reconfigures itself to replace the faulted online converter. The
BU also uses the HSB to monitor configuration changes made to the online
converters by either remote control or front panel command inputs.
