When light reflected from an object passes through a video camera lens that light is converted into an electronic signal by a special sensor called a Charge-Coupled device (CCD). Top-quality broadcast cameras and even camcorders may have as many as three CCDs(one for each color of red, green and blue) to enhance the resolution of the camera.
The output of the CCD is processed by the camera into a signal containing three channels of color information and synchronization; pulse (sync). There are several video standards for managing CCD output, each dealing with the amount of separation between the components of the signal .The more separation of the color information found in the signal ,the higher the quality of the image (and the more expensive the equipment).
If each channel of color information is transmitted as a separate signal on its own conductor, the signal output is called RGB(red, green and blue),which is the preferred method for higher-quality and professional video work. Output can also be split into two separate chroma (color) channels, Cb/Cr(blue and red chroma components) and a luma component channel (Y),which makes the dark and light part of the video picture. These components are often confused with the YUV color space in which time=Y, x-axis=U and y-axis=V.
Further confusing things, the non-RGB component cables usually have red, green and blue plugs and jacks, even thought the two methods of signal transfer are not compatible. Lower in quality is the Y/C signal that makes up Separate Video (S-Video),an analog video signal, used in Super VHS and Hi-8 video. As with component video, the Y indicates the brightness (or luminance) information, but in S-Video color (or chrominance), information is combined and designated.
The least separation (and thus the lowest quality for a video signal) occurs when all the signals are mixed together and carried on a single cable as a composite of the three color channels and the sync signal; this system yields less-precise color definition ,which cannot be manipulated or color corrected as much as an RGB or component signal.
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