) systems. We will involve the reader with wideband amplifiers in tandem, and the special impairments that we would expect to encounter in a CATV system. System layout, hubs, and last-mile or last 100-ft considerations will also be covered. There will also be a brief discussion of the conversion to a digital system using some of the compression concepts covered in Chapter 16. Employing these compression techniques, we can expect to see cable television systems delivering up to 500 TV channels to customers. 17.2 THE EVOLUTION OF CATV 17.2.1 The Beginnings Broadcast television, as we know it, was in its infancy around 1948. Fringe area problems were much more acute in that period. By fringe area, we mean areas with poor or scanty signal coverage. A few TV users in fringe areas found that if they raised their antennas high enough and improved antenna gain characteristics, an excellent picture could be received. These users were the envy of the neighborhood. Several of these people who were familiar with RF signal transmission employed signal splitters SO that their neighbors could share the excellent picture service. This concept is illustrated in Figure 17.2. Soon it was found that there is a limit to how much signal splitting could be done before signal levels got SO low that they became snowy or unusable. Remember that each time a signal splitter is added (i.e., a 50% split), neglecting insertion losses, the TV signal Mountain ridge Fringe area Figure 17.2 CATV initial concept. 17.2 THE EVOLUTION OF CATV drops 3 dB. Then someone got the bright idea of amplifying the signal before splitting. Now some real problems arose. One-channel amplifiers worked fine, but two channels from two antennas with signal combining became difficult. We have begun to enter the world of broadband amplifiers. Among the impairments we can expect from broadband amplifiers and their connected transmission lines (coaxial cable) are the following: Poor frequency response. Some part of the received band had notably lower levels than other par