User's Manual Part 1

Table Of Contents
3EM21522AAAA Functiona
l
Description
Issue 1, March 2008 DTR-0200-SA-SIRIUS
2-1
2 FUNCTIONAL DESCRIPTION
2.1
GENERAL
This section presents a functional description of the Sirius Terrestrial Repeater.
2.2
SYSTEM FUNCTIONAL OVERVIEW
Figure 2 - 1
shows the basic Repeater Simplified Functional Block Diagram.
The Sirius Terrestrial Repeater transmits at the 2.3265 GHz frequency with a 4.012
MHz signal bandwidth.
Refer to the tables in Section 1 for the technical characteris-
tics and the major components.
2.2.1
SIGNAL FLOW
The Sirius Terrestrial Repeater receives the video/audio Complex Digital Data
Stream (CDDS) signal in a TDM format at the KuBand from the satellite by means
of a Very Small Aperture Terminal (VSAT) parabolic antenna.
The CDDS signal passes through a Low Noise Block (LNB) converter to the DVB-S
L-Band satellite receiver;
an integral part of the Signal Processing Unit (SPU). The
satellite receiver demodulates the incoming stream and outputs the processed data
via the Asynchronous serial Interface (ASI) to the SIRIUS modulator stage.
The output of the modulator is an Orthogonal Frequency Division Multiplexed IF
(I and Q signals).
The IF is up-converted to an S-band frequency for insertion into the High Power
Amplifier (HP
A). The output of the HPA goes through the output bandpass filter
(BPF) where “out of band” generated signals are removed.
The output BPF signal (200W RF) goes through the output RF coupler to the tower
mounted antennas and is transmitted to the end user