China M/PAL Brazil D K/PAL Korea (DPR) Romania B G/SECAM Cyprus Egypt Germany Greece Iran Iraq* Lebanon Libya* Mali* Mauritania* Mauritius* Morocco Saudi Arabia Tunisia D K/SECAM Afghanistan* Bulgaria Czechoslovakia Hungary Mongolia* Poland USSR Viet Nam K1/SECAM Benin Burkina Faso Burundi Central African Republic Chad Congo Cote d'Ivoire (Ivory Coast) Djibouti* Gabon Guinea Madagascar Niger Senegal Togo Zaire L/SECAM France Luxembourg Monaco M/NTSC Bermuda* Bolivia British Virgin Islands* Burma* Canada Chile Colombia Costa Rica Cuba Dominican Republic* Ecuador* Guatemala* Haiti* Honduras* Jamaica* Japan Korea (Republic of) Mexico Montserrat* Netherlands Antilles* Nicaragua* Panama Peru Philippines* St. Christopher & Nevis* Suriname* USA Venezuela has for many years been the practice to reduce the bandwidth of one ability to resolve colour in small details of a picture is inferior to that of the two sidebands to produce vestigial sideband or asymmetric for corresponding black and white or grey pictures. Since the human sideband vision transmission. In System I the full upper sidebands eye does not resolve colour in small areas there is no need to to 5.5MHz are transmitted but the bandwidth of the lower sideband reproduce this, even for high quality television pictures (Figure is restricted to 1.25MHz (in 625 line System G as used in many 57.5). This influences many aspects of colour television, not least countries the lower sideband is restricted even more to 0.75MHz). the ability to limit the bandwidth of chrominance information This means that for System I the total vision bandwidth is 1.25 relative to that required for the luminance signal. In practice chro- 5.5 or 6.75MHz and a gap of 0.5MHz is left before the sound carrier, minance information in a 625 line system can begin to roll off at which is thus 6MHz above the vision carrier, as shown in Figure about 1.3MHz. The restriction of chrominance bandwidth makes possible inband transmission of chrominance information, although For both Systems I and G in the 