ABSTRACT
A monochrome receiver was able to display the new colour broadcasts in black and white, and a colour receiver could, in the same way, display the existing black and white broadcasts, which comprised the vast majority of transmissions until the mid-1960s. Extensive preliminary studies on colour perception and a great deal of ingenuity were required to define these standards which, despite their imperfections, still satisfy most of the end users more than 40 years after the first of them, National Television Standard Committee, came into being. In order to obtain the maximum bandwidth for luminance and to reduce cross-colour and cross-luminance, the phase of the subcarrier of the two interlaced lines of consecutive fields is reversed. The clever means of circumventing this problem consisted of considering that the colour information of two consecutive lines was sufficiently similar to be considered as identical.
