Broadcast Television Systems
1. Broadcast television systems are encoding or formatting standards for the transmission and reception of terrestrial television signals. There are three main analog television systems in current use around the world: NTSC, PAL, and SECAM. These systems have several components, including a set of technical parameters for the broadcasting signal, an encoder system for encoding color, and possibly a system for encoding multichannel television sound (MTS).
In digital television (DTV), all of these elements are combined in a single digital transmission system.
Source: Wikipedia