What is coposite video signal?

Answer 1

A composite video signal is a color video signal carried on a single cable. Color video signals have three separate components plus synchronization signals. They would normally require three separate cables to carry a brightness signal (with synchronization signals) and two color signals. Composite signals combine the brightness (luminance) signal with the two color (chrominance) within a single signal. The color encoding follows certain standards - PAL in UK and most of Europe, NTSC in North America.

Composite signals were developed prior to color television broadcasting with the main aim of allowing black and white televisions to receive a color signal. The encoding technique was patented in 1938, almost a decade before commercial color broadcasts began. In the early days of color television broadcasts, most televisions were black and white and it was not practical to build a completely new transmission infra-structure for the limited number of color televisions.

Since the 1950s color television has been broadcast in composite format and has not changed since. It is only in the 21st century that HD television is introducing a new signal format.

Today, composite is considered to be the lowest quality available. S-video, component, RGB and HDMI all offer higher quality signals. Despite the alternatives, composite signals have remained in common use because the difference is quality is not great and they provide a simple convenient method to connect equipment.