Cable TV got something of a bad rap when satellite TV became affordable to the average household back in the nineties and started to be available through smaller satellite dishes, but now companies like Comcast are taking advantage of new technology that promises to bring cable TV back into the position of being the leading way of getting TV service at home.

In order to fully appreciate the progress that cable TV has made over the past few years, you need to understand something about how it was delivered. It used to be that all TV was delivered using an analog signal that took up a lot of bandwidth and produced a certain unavoidable level of interference in even the best TV picture. This format limited cable TV providers to about a hundred channels at the most.

Thanks to digital TV though, Comcast an other cable TV companies have been able to up that number to nearly three hundred. Here’s how it’s done. Not only does digital TV consume less bandwidth than analog TV, but it can also be compressed to take up even less total bandwidth. This form of compression is very much like the compression that you might use to send a larger file through email, but it takes place on the fly and in real time through the cable TV system. There are currently two compression standards in wide spread use- MPEG-2 and MPEG-4. MPEG-2 is the common standard, but MPEG-4 video takes up as little as a fourth of the bandwidth of MPEG-2. In other words, if a cable TV company has enough bandwidth to deliver one hundred channels of MPEG-2 video, instituting MPEG-4 video compression could bring its total number of available channels up as high as four hundred! This makes Comcast and its peers competitive with satellite TV companies.

The cable TV industry in general, and Comcast in particular, in the process of instituting a new form of technology called Switched Digital Video (or SDV) which promises to remove all practical limitations on the number of channels that a cable TV company can provide! Switched Digital Video is revolutionary because it allows Comcast to deliver one channel to one viewer at any given time instead of the approach that has been used since TV’s inception of providing all channels to all viewers and then letting the viewers or their receiver equipment sort it all out. This obviously greatly expands the number of channels that can be provided by one of these services and is an especially good way to deal with the growing demand for HDTV channels, with their much greater bandwidth requirements.

SDV is also a good way to deliver video on demand services that Comcast has been in the process of instituting as well. Video On Demand puts the control over when a program is watched on the viewer rather than the network. Currently Comcast’s ON DEMAND service provides pay per view movies and a variety of other content through Video On Demand technology.

With it’s resistance to atmospheric interference and other advantages cable TV always was the best way to get TV, and now new technology is allowing it to live up to this potential.