Proposed SMPTE standard for Television - Composite analogue Video Signal, NTSC for Studio Application. This standard describes the composite colour video signal for studio applications, system M/NTSC, 525 lines, 59.94 fields, 2:1 interface, with an aspect ratio of 4:3. This standard specifies the interface for analogue interconnection and serves as the basis for the digital coding necessary for digital interconnection of system M/NTSC equipment. Note: Parts of the system M/NTSC signal defined in this document differ from the final report of the Second National Television System Committee (NTSC 1953) due to changes in the technology and studio operating practices.