Promax DT-800 Manual De Usuario página 78

COFDM:
MPEG-2:
DVB-T:
DVB-S:
TS-ASI:
LNB:
Page 32
Coded Orthogonal
modulation system used in the radio and televisión systems. Unlike
other systems that modulate in a single carrier frequency with a
very high rate of symbols, COFDM modulates information in many
carrier frequencies, where each one has a very low rate of symbols.
Moving Pictures Experts Group 2 (MPEG-2) is the designation for a
set of standards for encoding audio and video agree by MPEG (a
group of experts in moving images), and published as a ISO 13818
standard. MPEG-2 is usually used to encode audio and video for
transmisión signals, including digital terrestrial television, by satellite
or cable. With some modifications, is also the encoding format used
by DVD `s commercial films.
DVB-T is an abbreviation for Digital Video Broadcasting Terrestrial;
it is the DVB European-based consortium standard for the
broadcast transmission of digital terrestrial television. This system
transmits compressed digital audio, video and other data in an
MPEG transport stream, using COFDM modulation.
Digital Video Broadcasting by Satellite (DVB-S) is a system that
allows increasing the transmission capacity of digital television and
data via satellite using MPEG2 format. The structure allows mixing
in a stream a large number of video services, audio and data. For
transmissions via satellite the QPSK encoding is adopted, with a
binary variable flow from 18.4 to 48.4 Mbits / s. DVB-S format is
widely used in European countries.
(Transport Stream - Asynchronous Serial Interface): It is a protocol
especially designed for transmitting in media sensitive to noise and
used in the DVB standard (Digital TV distribution protocol) for the
transmission of compressed digital television signals. It is also used
as an interface of input and / or output multiplexers, MPEG-2
encoders, etc. ASI interface was created especially for transporting
MPEG transport streams, is extremely flexible and can carry data at
any speed from zero to over 200 Mbit / s.
The Low Noise Block amplifier or LNB is a device consisting of a
low noise amplifier and a frequency converter (RF to IF). The
reason for use a universal LNB is motivated because it can get all
the bandwidth (the low-band, from 10.7 to 11.7 GHz, and the high-
band, from 11.7 to 12.75 GHz). This allows the reception of all
analogue channels with an analog receiver, and all digital channels
with a digital satellite receiver. The universal LNB selects the low-
band or the high-band, when activating a tone switch of 22 kHz
generated by the digital receiver. Horizontal and vertical polarization
is selected by applying 13 or 18 volt to the power supply.
CONTROL MODULE. DT-800
Frequency Division Multiplexing is the
04-2012