ewers have come to expect from television, but they rarely get to work with comparable bandwidth or service quality. IN LIVING COLOR-NTSC Acquaintance with the color television system that the NTSC approved in 1954 facilitates comprehension of video communication technology. Before it devised the NTSC system of color telecasting, the committee considered various solutions. Members soon realized they could not expand on the existing monochrome approach by using separate RGB subcarriers. This would have been a synchronization nightmare and would have required that the bandwidth allocated to each TV channel be greatly expanded to convey not only luminance but also red, green, and blue signals. This was not practical. Nor was it acceptable to simultaneously broadcast a program in both monochrome and color. They required a hybrid system that could superimpose color information (chroma) over the brightness (luma) signal. Colordots Green beam Blue beam Redbeam Viewing screen Electron beams pass through hole together Shadowmask Figure 5-12. Shadow Mask (Michel Bayard). The system that the NTSC selected used this approach and added hue (the identifiable color) and color saturation (color intensity, e.g., pastel pink, bright red, rose) to the luma signal. It did this by exploiting luminance's occupation of the 4.2 MHz subcarrier in bursts of energy at harmonic multiples of the horizontal scanning rate. This creates frequency clusters with empty spaces in which hue and saturation signals can be inserted. Hue and color saturation are thus inserted in these empty spaces using a technical concept described as frequency interleaving. The NTSC selected the frequency of the color subcarrier 3.579545, rounded 3.58 MHz, to Video Communications: The Whole Picture achieve compatibility with the installed base of monochrome television sets. The NTSC color television system is detailed in a document prepared by the Electronics Industries Association (EIA). This highly technical document, known as RS-170A, describes how color is added t