Analog Video

Television Systems

The exact frame rate depends on the system as does the number of scan lines per frame
There are currently three conventional commercial television systems in use throughout the world.
Television Systems
SystemScan lines/frameFrame ratePixels/frameBandwidthColor
NTSC52530130 0004.3 MHzYIQ
PAL62525210 000k6 MHzYUV
SECAM62525210 0006 MHzYUV

Types of Video Signals

Component Video
Higher end video systems make use of 3 separate video signals for the R,G and B image planes.
Most computer systems use component video.
There is no crosstalk between the 3 channels.
However, it requires more bandwidth and requires good synchronization of 3 components.

Composite Video
Color (chrominance) and intensity(luminance) signals are mixed into a single carrier wave.
Chrominance is a composite of 2 color components (I and Q or U and V)
The chrominance and luminance can be separated at the receiver end and then the 2 color components can be further recovered.
Some interference between the color and intensity signals cannot be prevented.

S-Video
As a compromise, Separated Video uses 2 wires. One for luminance and the other for a composite chrominance signal.
As a result, there is less crosstalk between color information and the crucial gray-scale information.
Gray-scale information is more important.
Carries standard definition video (typically at 480i or 576i resolution), but does not carry audio on the same cable.
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