Function Reference
TELETEXT
5
5-13
Figure 5-7. Teletext Page 100
Figure 5-8. Teletext Page 200
Checking and Adjusting
The teletext data signal consists of high speed pulses and transients which are sensitive to
amplitude and delay distortions, noise, and spurious pulses. The success of a TV
receiver to decode the digital data without error depends on the amount of distortions in the
total signal path. Teletext data and the analog TV signal are affected in different ways.
Many teletext lines of the 54200 are especially generated for checks and adjustments. Ad-
justments of teletext decoders depend on the applied components, especially on the built-in
integrated circuits. For detailed adjustment procedures of teletext decoders, refer to the ap-
propriate Service Manuals.
Character sets of a teletext decoder can be checked by the teletext pages 200 to 205
(Teletext B). Characters are shown correctly for the indicated languages only if the teletext
decoder of the TV offers the West European languages. If the TV has a different decoder
the characters generated by 54200 are shown in the corresponding language. Eight differ-
ent languages are controllable by Page Header Control Bits (C12 to C14) of the teletext
data. For example, the character set of Page 200 is shown by a decoder for Western
Europe in British and will be shown in Polish with a decoder for Eastern Europe.
Details of character data input decoding for different countries and languages in teletext
decoders are shown in data sheets of the supplier, for example, Philips SAA5246A.
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