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5.3 Teletext
5.3.1
Description and specifications
What is “Teletext”?
Teletext is the name of a system used to send still picture program data of text and graphics after
multiplexing it in the vertical sync blanking interval of the TV signals. Programs broadcast in Teletext
include subtitled broadcasts, news broadcasts, weather forecasts and stock market information.
Teletext has achieved a high penetration rate in various countries in Europe and Southeast Asia
where the 625/50i system is used.
With Teletext, a total of 40 characters × 25 lines can be contained on a page (per screen), and
between 100 and 899 pages of information can be displayed.
Teletext specifications
Teletext supports the following TV signals.
Teletext is superimposed onto the composite signals and Y/C signals.
• PAL (but PAL-60, PAL-N and PAL-Nc are not included.)
The vertical sync blanking interval (VBI) and Teletext waveforms are shown below.
The Teletext data can be output in lines 8 to 22 (first field) and lines 321 to 335 (second filed) in the
vertical sync blanking interval of the PAL signals.
A total of 45 bytes consisting of the Clock Run-In, Framing Code and data bytes (42 bytes) are
superimposed in one line.
VBI waveforms
Clock Run-In
66IRE
0I
RE
1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 1 1 0 0 1 0 0
Framing
Code
2byte
1byte
45byte
Teletext
Teletext waveforms
Содержание VG-870B
Страница 1: ...Programmable Video Signal Generator VG 870B 871B 873 874 Instruction Manual Ver 3 80 ...
Страница 2: ......
Страница 4: ......
Страница 14: ...x ...
Страница 58: ...40 ...
Страница 220: ...202 4 12 8 DDC CI For further details on the setting procedure refer to 6 13 4 DDC CI ...
Страница 229: ...Chapter 4 INTERFACE SETTINGS 211 Set LFE Playback Level 0 Unknown 1 0dB Playback 12 LFE PB Level 2 10dB Playback ...
Страница 286: ...268 ...
Страница 300: ...282 7 Interval 0 to 60 Interval The interval at which the V chip data is transmitted is set in 1 second increments ...
Страница 362: ...344 0 1 2 3 4 5 6 ...
Страница 394: ...376 ...
Страница 426: ...408 ...
Страница 450: ...432 ...
Страница 537: ...Chapter 11 SPECIFICATIONS 519 F0H letters me 1 F1H letters me 2 VESA specifications ...
Страница 538: ...520 F2H Chinese character AI F3H Chinese character BI ...
Страница 539: ...Chapter 11 SPECIFICATIONS 521 F4H Chinese character TAKA F5H Chinese character KIRI ...
Страница 540: ...522 F6H Chinese character KEN F7H Burst ...
Страница 541: ...Chapter 11 SPECIFICATIONS 523 11 3 4 Character pattern data 5 7 character pattern table 1 of 2 ...
Страница 542: ...524 5 7 character pattern table 2 of 2 ...
Страница 543: ...Chapter 11 SPECIFICATIONS 525 7 9 character pattern table 1 of 2 ...
Страница 544: ...526 7 9 character pattern table 2 of 2 8 9 dots are used for 80H to 8FH ...
Страница 545: ...Chapter 11 SPECIFICATIONS 527 16 16 character pattern table 1 of 4 ...
Страница 546: ...528 16 16 character pattern table 2 of 4 ...
Страница 547: ...Chapter 11 SPECIFICATIONS 529 16 16 character pattern table 3 of 4 ...
Страница 548: ...530 16 16 character pattern table 4 of 4 ...
Страница 554: ...536 ...