Operation Manual Part 1

Digital Liquid Cooled UHF
TV Equipment
Description / Test points / Location of units
9946 V1
45321648.01 104 A E
preliminary
40 / 131
Numéro / Number Doc. Rev. Lan
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16/06/2006
Pa
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e
Information contained is this document is confidential, is THOMSON property and cannot be disclosed in whatever form without prior written authorization of THOMSON.
3.2.2. Applications
The sirius exciter is designed to serve three functions for MediaFLO, i.e., channel coding, RF
modulation and manages analogue interface to the transmitter. The exciter, which complies with the
MediaFLO Air interface specification, provides the basic functions of converting an MPEG transport
stream and converting the resulting data to a MediaFLO modulated IF signal.
The exciter supports the 4K operating mode and mandatory SFN operation.
The primary application is as a terrestrial TV transmitter exciter and thus special attention has been paid to
optimizing the total transmitter performance. The COFDM signal itself is very complex with respect to
frequency and amplitude and non-linear behaviour of the transmitter power amplifier will cause
difficulties for reception as well as interference into adjacent channels. Hence the unit is equipped with
an adaptive amplitude and phase non-linearity pre-corrector which digitally optimizes the transmitter
performance and thus increases the coverage area available at a given output power level Moreover
an adaptive linear-pre-corrector is implemented to compensate eventual amplitude and phase
inconveniences of combiner filters etc.
Also due to the complexity of the COFDM signal, the alignment of transmitters is cumbersome.
However the built-in test signals greatly facilitate this alignment.