Operation Manual Part 1

Digital Liquid Cooled UHF
TV Equipment
Description / Test points / Location of units
9946 V1
45321648.01 104 A E
preliminary
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Numéro / Number Doc. Rev. Lan
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16/06/2006
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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. Rack : SIRIUS DVB-T UHF 45321627.11
3.2.1. Introduction
The sirius exciter is a key element for Media FLO
TM
transmitting technolongy
The quality of coding and modulation is particularly important to the MediaFLO process. Hence the
Sirius exciter has been designed to fulfil the most demanding requirements with respect to
performance as well as flexibility in application and operation. Strict adherence to the MediaFLO
system specifications is of course a must, but also additional features have been added to the exciter
to enhance the value of a given transmission system. Thus emphasis has been placed on easy
interfacing to both the signal distribution system and, in particular, to the final TV transmitter, to ensure
maximum transmitter coverage at the lowest cost.
Although the TV signal for MediaFLO is coded in a very robust way, thus making it quite rugged, the
fact remains that once it is coded and modulated into a MediaFLO physical layer. The exciter
compensates the traditional distortions and impairments known from analogue TV will take over in a fast
and efficient way.
In digitally transmitted TV signals, factors like noise, inter modulation and non-linearity play a much
larger role than in analogue TV signals as they may very well prevent reception and decoding as a
whole. This means that the analogue performance of a COFDM exciter is of utmost importance. In the
case of the Sirius exciter special thought has been given to the design of the areas that have an influence on the
analogue performance.
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