WHAT IS NTSC

Short for “National Television System Committee”. The NTSC is responsible for setting television and video standards used in North America, most of South America and some other countries. The NTSC standard for television defines a composite video signal with a refresh rate of 30 interlaced frames per second. Each frame contains 525 lines and can contain 16 million different colors.
The term NTSC may also be used to describe any video, including digital video, formatted for playback on a NTSC TV. This generally includes any Standard Definition (SD) video with a vertical Resolution of up to 480 Pixels and a horizontal Resolution no greater than 720, which also has a Framerate of 29.97fps. NTSC is sometimes referred to as 525/60, in reference to the total number of lines (including lines not in the Active Area) and approximate Fieldrate. Digital formats include only 480 of NTSC's 486 visible Scanlines due to the need to guarantee mod16 Resolution, meaning its divisible evenly by 16.
The NTSC standard is incompatible with most computer video standards, which generally use RGB video signals. However, you can insert special video adapters into your computer that convert NTSC signals into computer video signals and vice versa.

N T S C National Television System Committee
Lines/Field	525/60
Horizontal Frequency	15.734 kHz
Vertical Frequency	60 Hz
Color Subcarrier Frequency	3.579545 MHz
Video Bandwidth	4.2 MHz
Sound Carrier	4.5 MHz

The first black-and-white NTSC standard for broadcast was developed in 1941 and had no provision for color transmissions. Civilian development of commercial television was halted with the entry of the United States into the war. In 1953 a second standard was issued, which allowed color broadcasting to be compatible with the existing stock of black-and-white receivers, while maintaining the broadcast channel bandwidth already in use.
NTSC was the first widely adopted broadcast color system. After over a half-century of use, the vast majority of over-the-air NTSC transmissions will be replaced with ATSC.