Scanning system
A scanning system is the combination of lines-per-frame and frames-per-second which describes the way in which a television signal is encoded and transmitted.
Common US NTSC color television is 480/30i, or 30 interlaced frames per second with 480 active scan lines of picture (this is the standard which used to be described as 525/60 -- 525 total scanning lines including the vertical blanking interval, and 60 fields per second).
The common standard in the UK and much of Europe is PAL color on 576/25i scanning (625/50).
Common HDTV standards now include 1080/30i and 720/30p.
A complete table listing all the known active combinations of scanning and color system is here. The letter codes are the ones often seen in discussions of tuners on tuner cards: PAL-B, PAL-D/K, etc.
