Bill - Thanks. I'm a little surprised, especially since the cable industry is in the process of going digital anyway - to compete with DBS systems. The more I think about it, the more I think it is a credible explanation. For instance, the cable companies may only be able to get 4-1 greater bandwidth efficiency (because of the noise problems you describe), while broadcast gets 6-1; if both systems are equally saturated, then cable has a problem?
In a somewhat similar vein, do you know of any studies of the link budgets for HDTV in current service areas? For instance, I would imagine that they will either have to replace most of their transmitters, or decrease the power out (to increase the linearity) and install extra repeaters. (As a side question, qualitatively, do you know how bad an analog signal has to look before a digital signal thru the same system is junk - I realize it depends on the kind of problem (non-linearity, multipath,...), but nonetheless, ...?)
Clark |
