SIMULATION OF TELETEXT ENCODER AND DECODER

Abstract

Teletext is the technique of broadcasting public information over a wide geographical area along with the normal television picture signals. A viewer can select any of the transmitted text, ordata to be displayed on the television screen by using a suitable decoder instrument. Teletext is a system for one way broadcast transmission of information primarily in text form with graphics capability. It uses .. spare channel capacity in TV transmission system, and modified domestic TV receivers. This is achieved by converting the information into digital data. This data is then added into the same broadcast TV signal that carries the ordinary TV picture. Viewers who are watching the normal television picture are unaware that their TV signal contains this extra data also. This is due to the fact that the picture they see is not disturbed in any mariner. However, any TV set equipped with special plug-in-box (called decoder) can receive the public data. The decoder extracts the hidden data from the TV signal and rejects the normal picture. The decoder then displays the data as a page of text on the screen. Thus the public data can reach any place that has television coverage, and no extra installation effort is required beyond setting up a television.......