itu-r bt.470标准 pdf

Rec. ITU-R BT.470-6 1
RECOMMENDATION ITU-R BT.470-6*
CONVENTIONAL TELEVISION SYSTEMS
(Question ITU-R 1/11)
(1970-1974-1986-1994-1995-1997

The ITU Radiocommunication Assembly,
considering
a) that many countries have established satisfactory monochrome television broadcasting services based on either
525-line or 625-line systems;
b) that a number of countries have established (or are in the process of establishing) satisfactory colour television
broadcasting services based on the NTSC, PAL or SECAM systems;
c) that the use of video component signals, signals consisting of the luminance and two colour difference signals,
with time compression and time division multiplexing, may offer picture quality benefits, using new types of television
receivers;
d) that it would add further complications to the interchange of programmes to have a greater multiplicity of
systems,
recommends
1 that, for a country wishing to initiate a conventional monochrome television service, a system using 525- or
625-lines as defined in Annex 1 is to be preferred;
2 that, for conventional monochrome 625-line systems, the video-frequency characteristic described in
Recommendation ITU-R BT.472 is to be preferred;
3 that, for a country wishing to initiate a conventional colour television service, one of the systems defined in
Annex 1 is to be preferred.
NOTE 1 – Pre-1986 editions of the ex-CCIR Volumes, and in particular that of 1982, contain a complete description of
system E used in France until 1984, and system A used in the United Kingdom until 1985.
NOTE 2 – Pre-1997 editions of Recommendation ITU-R BT.470 contain a complete description of the SECAM IV
colour television system.