525-line (or EIA 525/60) is an American
standard-definition television resolution used since July 1, 1941,[1][2][3] mainly in the context of analog TV broadcast systems. It consists of a 525-line
raster, with 480 lines carrying the visible image at 30
interlacedframes per second. It was eventually adopted by countries using 60 Hz
utility frequency as TV broadcasts resumed after World War II. With the introduction of color television in the 1950s,[4] it became associated with the
NTSC analog color standard.
The system was given their letter designation as CCIR System M in the
ITU identification scheme adopted in Stockholm in 1961.
A similar
625-line system was adopted by countries using 50 Hz utility frequency. Other systems, like
375-line,
405-line,
441-line and
819-line existed, but became outdated or had limited adoption.
The modern standard-definition
digital video resolution
480i is equivalent to 525-line and can be used to
digitize a TV signal, or to it playback generating a 525-line compatible analog signal.[5]
The following
analog television color systems were used in conjunction with the previous standards (identified by a letter after the color system indication):
^National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplementary references cited in the Reports, and the Petition for adoption of transmission standards for color television before the Federal Communications Commission, n.p., 1953], 17 v. illus., diagrs., tables. 28 cm. LC Control No.:54021386
Library of Congress Online Catalog