Sunday, October 05, 2008
For years the cable TV industry addressed this disparity by investing massive amounts of money in expanding the bandwidth of the cable TV system. Now, with those upgrades, the cable TV providers can offer service that's somewhat comparable with what most satellite TV providers currently offer.
Unfortunately for the cable TV providers, just meeting the present capacity of the satellite TV providers isn't good enough. That's because demand for HDTV programming is increasing and each HDTV channel takes up about ten times the bandwidth of a standard definition TV channel. Therefore, with companies like Directv claiming to be able to offer one hundred HDTV channels by years end, the cable TV industry needs to do something new.
The common sense course of action is to upgrade the existing cable networks yet again in order to increase the bandwidth that much more, but cable TV companies don't want to take on more debt, charge their subscribers more, or see more investment capital. Fortunately there's a new technology that provides an alternative.
This new technology is called Switched Digital Video or SDV for short and it takes advantage of the fact that while the cable networks don't have enough bandwidth to offer five hundred or one thousand channels, they do have plenty of bandwidth to offer one channel at a time. Basically, Switched Digital Video changes the way that TV is supplied to each individual household so that each household only gets the TV signal for the program that's currently being watched rather than getting the signals for all of the programs and only displaying one on the TV. Right now the latter scenario is how TV programming is supplied to cable TV viewers. Each household receives all of the channels that are offered by the cable TV company and then the household's receiver filters out the unwanted channels (and the ones that aren't part of the subscription) and displays a single channel on the TV set. While obviously inefficient, this was a very effective strategy given the level of technology that has existed for most of the lifetime of the cable TV industry.
Now though, we have much better technology that allows the receiver to request a feed to a certain channel when that channel is selected by the viewer. Then, in much the same way that a Web server delivers a document to an individual computer over the Internet, the cable TV company delivers that channel to the receiver and viewer. This way only one channel worth of content has to be delivered at one time. Even HDTV programming can't take up all of that available bandwidth and the bandwidth that's left over can be used for phone service or high speed Internet access.
Switched Digital Video is a clever way to more efficiently use the bandwidth that cable TV companies already have access to and is sure to give the satellite TV industry a run for its money.