By Alex Best, Scientific-Atlanta, Inc.
The movement of cable TV over the past few years from the rural areas into the large metropolitan areas has brought with it new demands on the techniques of processing signals. To a large degree these changes in processing requirements have been dictated by the fact that in metropolitan areas, the best geographical location for receiving signals off-air is separated by some distance from the most convenient office and local origination site, and in most instances both of these are located some distance from the optimum point to distribute the signals. Headend electronics capable of operating in this environment without producing excessive degradation have increased the technical performance specifications of head end equipment, especially heterodyne signal processors. To investigate these increased performance demands, consider a "typical" headend system for a metropolitan area such as the one shown in Figure I.