Promax PROLINK-4C, Manual

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USER’S MANUAL. PROLINK-4C
Page 52 02/2003
4.9.2 DVB Channels Identifier: DCI
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function
This function permits to identify DVB channels. It provides information of
channel on which the BER measurement is made, as well as access to each one of the
services contained in the resultant Multiplex of channel demodulation.
The DVB group recommends to digital TV service operators the codification on
the Transport Stream of some particular fields containing data information. The
Transport Stream is a sequence of packets, of constant length, which carry video
information or audio or data.
Data packets can be grouped to constitute TABLES, some of these tables
content information defined by the network operator and which show the type of service
that is being supplied to the users. Among the different data defined in these tables, the
most frequently used data for channel identification purposes are:
Network:
It contents the name given to the set of all the Transport Stream
managed jointly inside of a network formed by several physical
communication channels. In case of satellite television, also
contains the satellite orbital position pointed by the parabolic dish.
This information is extracted from NIT (Network Information
Table).
Service: It contents the names of video, audio or data services present in the
Transport Stream. This information is extracted from SDT
(Service Description Table).
Bouquet: It contents the name given to the set of all the services
commercialized as one entity. The information, that in this case
DVB defines as optional, is extracted from BAT (Bouquet
Association Table) or from SDT.
Provider: It contents the provider name, which offer certain services. Within a
Multiplex one, each one of services can have its own provider, but
normally all services have a same provider. This information is
extracted analyzing the SDT.
In case the operator includes this information, the three fields are not
transmitted at the same time but they appear alternatively in different packets. Besides,
the cadence of presentation of each one of these packets may vary from one operator
to another.
When tuning a DVB compatible transponder, the DCI function (DVB Channels
Identifier) detects those data packets including service information relative to these
three fields and shows on the lower line on the screen the information contained in them
automatically.
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DCI, Device and Procedure patented by PROMAX ELECTRONICA, S.A. (Patent 9901632)