Introduction

Three different systems of colour television (CTV)

  1. The American NTSC (National Television Systems Committee) system.
  2. The German PAL (Phase Alteration by Line) systems.
  3. The French SECAM (Sequential Couleures a memoire) system.


India adopted the PAL system (B & G standards)

  • for compatibility with the existing 625 line CCIR (B standards) monochrome system.
  • due to its superior performance over the other two systems.

In many respects transmission and reception techniques employed in the NTSC and PAL systems are similar.

COLOUR SIGNAL TRANSMISSION

Hurdles:

  • colour video signal contains two independent information: hue and saturation.
  • Difficult to modulate them on the same carrier in such a way that these can be easily recovered at the receiver without affecting each other.
  • need to fit this colour signal into a standard TV channel which is almost fully occupied by the ‘Y’ signal.
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