A Zenith proposal for an HDEP scheme that would use three times as many scanning lines as NTSC (1575), but would otherwise retain NTS characteristics. It is said to allow easy standards conversion to 525- or 625-scanning line systems and to accept material shot in 1125 scanning lines in a 16:9 aspect ratio without difficulty. 3XNTSC would have 1449 active scanning lines, 2:1 interlace, a 4:3 aspect ratio, and a bandwidth of 37.8 MHz.