> That 6 MHz is used to encode MPEG-2 frames containing video, color, and audio information that your cable box or TV decodes into picture and sound. If you graphed a single channel provided by the cable operator, it would look similar to Figure 2-2.<p>> A DOCSIS channel can be graphed in the same fashion; however, instead of video, color, and audio information inside the MPEG-2 frames, it contains a data stream that represents computer information. Due to the "spectral shaping" of a data signal, there are no video or audio signals present, and the graph looks like Figure 2-3.<p>this seems wrong. i think figure 2-2 is an analog ntsc video channel and figure 2-3 is a digital mpeg-2 or docsis over mpeg-2 channel. both of the digital channels should have the same spectral envelope.<p>interesting that they put mpeg-2 headers on the data frames, probably "system" frames and done so for compatibility with existing headend and stb equipment.