LENCO TFT-711 -, Руководство пользователя

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LENCO TFT-711 ENGLISH
ABBREVIATIONS AND GLOSSARY (INFORMATIVE)
24 Hour Channels Channels that are only broadcasted at certain hours of the day. Depending network provider,
the channel information is available in the DVB-T stream and the TFT-711 receiver is
programmed to list these channels in the TV or Radio list after an Automatic or Manual Scan.
Conditional Access (CA) Conditional access refers to methods that scramble or encrypt the program or private data so
that it may be received only by ‘authorized’ receivers.
Carrier-to-Noise Ratio (C/N
or CNR) A measurement of the received carrier power relative to the power of background noise at the
receiver input.
COFDM A method of coded OFDM used by DVB for digital terrestrial television broadcasting (see
OFDM).
DASC Digital Active Signal Collector. A specially designed mini Active antenna to receive DVB-T
signals on portable receivers.
Digital Nature of signals utilized in modern transmissions. Compared to analogue, digital clutters the
spectrum less (all available frequencies). With constant bandwidth, digital broadcasts more
channels than analogue. Digital channels have been in existence for several years on cable
and satellite. In time they will replace analogue channels in Terrestrial transmission. Note: the
same channel can be transmitted in both analogue and digital form.
Digital Video Broadcast
(DVB) The digital video broadcast is a consortium of manufacturers, research institutes, and
broadcast organizations principally located in Europe but spread throughout the world. The
Project has produced a series of interlinked broadcasting standards for satellite, cable and
terrestrial.
DVB-T Abbreviation for Digital Video Broadcasting Terrestrial = terrestrial digital television. TV
reception is only possible in DVB-T transmission zones. The DVB-T terrestrial digital television
broadcasting specification is based on a transmission system of COFDM carrying program
and data as MPEG packets. It was approved by the Steering Board, in December 1995 and
subsequently accepted by ETSI as a European Standard. The work was based on a set of
user requirements produced by the Terrestrial Commercial Module of the DVB Project. DVB
members contributed to the technical development of DVB-T through the DTTV-SA (Digital
Terrestrial Television—Systems Aspects) of the Technical Module.
EPG Electronic Program Guide. Broadcasters using DVB, transmit program schedule information in
Event Information Tables (EIT) tables. These tables may be in several different forms
containing - immediate information (EIT now/next, also known as EIT pf - present/following)
and in limited cases, future program information (known as EIT schedule) – related to the
transport stream carrying the EIT or other (broadcasters’) transport streams.
ETSI European Telecommunication Standards Institute, the major European Standards publishing
body
Free-To-Air broadcaster
(FTA)
FTA broadcasters offer their programs and related material, where receivable, to be freely
accessed by the public. This contrasts with subscription or pay broadcasters that impose a
charge on a viewer/listener to access their material. FTA broadcasters may be government,
community or commercially (advertising) funded.
Forward Error Correction
(FEC) Methods of improving the ability to recover error-free data from a transmission or storage
system usually by adding extra data (about the payload data) before transmission. For
example in DVB-T, a system of FEC referred to as ‘Viterbi’ or ‘inner’ coding can be set to
different levels from 7/8 to 1/2 with 1/2 providing the most error protection. Further error
protection known as Reed-Solomon adds a further 16 bytes to the 188 Byte MPEG-2 transport
stream packet making a new packet size of 204 bytes.
Guard Interval In order to use all same channel signals and reflections not arriving at the receiver
simultaneously, the first part of the transmitted signal is not used for data transmission. This
part is called the guard interval and can be set to various lengths such as 1/4, 1/8, 1/16or 1/32.
International Organization
for Standardization (ISO) An international Standards body, commonly known as the International Standards
Organization.
ITU-R International Telecommunication Union Radio communication. An international Standards
body and a part of the ITU, based in Geneva which is the recognized Standards publisher for
broadcast radio and television transmission standards and Standards on international program
exchange.
LCN Logical Channel Number
MFN (Multi Frequency
Network) A network of DVB-T Stations using various radio frequency channels
Moving Picture Experts
Group (MPEG) A voluntary body ISO/IEC Joint Technical Committee 1, Sub Committee 29/Working Group 11
which has and continues to develop Standards for digital compressed moving pictures and
associated audio. MPEG Standards are published in the ISO/IEC 11172 (MPEG-1), and
ISO/IEC 13818 (MPEG-2) series of documents.
MPEG-1 & MPEG-2 Also refer to entry under ‘Moving Pictures Experts Group (MPEG). These are the most
common video and audio compression schemes now in use. MPEG-1 was used for lower data
rate video on early CDi and Video CDs. MPEG-2 provides for better quality (at higher data
rates) and is used in a variety of professional and consumer applications on terrestrial, satellite
and cable broadcast and DVD.
MPEG-1 layer II audio The compressed audio Standards of MPEG-1 were published in the 1993 International
Standard ISO/IEC 11172-3. This dealt with mono and two-channel stereo sound coding, at
sampling frequencies commonly used for high quality audio (48, 44.1 and 32 kHz). Compared
to Layer I, Layer II is able to remove more of the signal redundancy and to apply the
psychoacoustic threshold more efficiently. The development of audio standards for MPEG-2
resulted in the 1995 International Standard ISO/IEC 13818-3.