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ÖNORM EN 300706 V 1.2.1:2003-08
Enhanced Teletext specification
Действует
Печатная копияПечатное издание
193.28 € (включая НДС 20%)
Разработчик:
Зарубежные/ON
ICS:
33.050.30 Equipment for telex, teletext, telefax / Аппаратура для телексов, телетекстов, телефаксов
Описание
The present document defines the application of CCIR Teletext System B to CCIR 625 Line 50 field Television
Systems B, D, G, H, I, K and L. The System is optimized for broadcast media using cable, terrestrial and satellite
transmission and the associated service and product environment. Reliable reception of data is ensured, since there is a
good match between the service area defined for vision and sound reception and that provided for Teletext data
broadcasting.
The data is organized in a manner optimum for broadcast media by using the rigid timing framework of the television
signal. When multiplexed with a video waveform, this permits a fixed relationship to be provided between the data
bytes on a television signal data line and locations in the decoder memory. Using this relationship, error identification
and correction are available, matched to the statistical occurrence of bit errors. Critical control data and addressing
information are protected by Hamming coding. Basic data is protected by using parity checks.
Teletext data packets are normally grouped together to form "pages" of information, although some have a
"stand-alone" function. The range of presentation and application features are arranged to be downward compatible.
This permits initial services to be defined and existing services to be upgraded, without rendering obsolete equipment
already in the field.
Four presentation Levels are defined:
Level 1: - alphamosaic characters;
spacing attributes;
fixed colour palette;
24 rows of 40 columns;
Level 1.5: - extends the character repertoire;
Level 2.5: - extends the language repertoire;
increases the colour palette with re-definable colours;
introduces non-spacing attributes;
allows a number of simple re-definable characters;
provides side panels for additional text or graphics;
Level 3.5: - extends the number of re-definable characters and their complexity;
introduces di (...abbreviated)
Ключевые слова:
Telekommunikation, Fernmeldetechnik, Nachrichtentechnik, Kommunikationstechnologie, Informationsverarbeitung, Teletext, Fernsehen, TV, Fernsehtechnik, Übertragung, Datenübertragung