Promax PROLINK-4C, Manual

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USER’S MANUAL. PROLINK-4C
Page 54 02/2003
In digital television is used the Transport Stream, in which two types of packets
can be distinguished clearly: those that content packetized video or audio, and those
that content the information necessary to be able to accede to video or audio. These
last ones form the specific information of the programs (PSI, Program Specific
Information), and allow to construct a series of tables that store the organization of the
programs or services that there are in the Multiplex, as well as data about their
conditional accesses (in case they are encrypted).
The DVB standard adds to tables MPEG-2 a few tables more than they offer
very useful complementary information in the case of digital television, between which
they emphasize the service table (Service Description Table), the network table
(Network Information Table), and the bouquet table (Bouquet Association Table).
In the list of services they will appear all the present services in the service table
according to the ETS 300 468 standard. Therefore will appear the decodable services
by any digital television decoding system that satisfies the MPEG-2 / DVB standard, as
well as the data services, the utility reserved services by the operator, and even the
discontinuous transmission services that, however, have been specified in the service
table outside of its hours of transmission.
The specification for the Service Information in DVB systems, recommends
that the table that contents the description of services (SDT, Service Description
Table), was faithful to services that at every moment are contained in the Multiplex.
Even so, it is responsibility of the operator that content of this one and other tables is
updated or that only correct information is contained.
When the BER measurement indicates acceptable reception quality (always to the
left of the QEF level), and the identification information confirms that you have found the
required channel, you will be able to ask for decoding some video and/or audio service.
Figure 22.- Tuning a digital channel with acceptable BER level.
For decoding any service there are two possible procedures:
1) Go to the service list, option service list from functions menu in digital mode.