Saturday, November 29, 2008

Best Comcast Cable Promotions

By Rachel Smith

The cable TV industry is coming out with a new type of technology that promises to change how we enjoy television by changing the way television is delivered to our homes. The technology is called switched digital video and it represents a paradigm shift in how TV programming is delivered to the home. In order to understand switched digital video and its impact on how people will watch TV, it's necessary to understand how TV has been delivered to homes in the past.

For decades TV has been transmitted from TV stations to homes in basically the same way. Whether the transmissions take place over the air, through a cable, or via satellite; all of the available channels have been transmitted to all of the households that receive them all at once. At the receiving end of the transmission, something filters out the unwanted channels. In the case of an analog over the air TV transmission, this means tuning into a specific frequency while tuning out all of the others. In the case of satellite TV and earlier cable TV technology this means that the digital receiver box finds the signal that carries the one channel that the viewer wants to watch and then filters out all of the others. In short, with this method of TV transmission, all of the available channels are being transmitted all the time to every potential viewer, regardless of which channel a given viewer is watching at any given time.

Switched digital video changes this decades old paradigm by only transmitting the channel that the viewer wants to watch. This is done through two way communication between the viewer's receiver box and the transmission station. Basically, when a viewer wants to change channels, the receiver sends a request for the new channel to the transmission station. The transmission station then stops transmitting the old channel and sends the new one in its place. This allows the cable TV company to offer more channels because those channels don't have to be transmitted over a cable with finite bandwidth all at once.

This switched digital video technology puts cable TV at an advantage over satellite TV and over the air TV for one simple reason: cables do a much better job of carrying information in two directions than the electromagnetic radiation that over the air TV and satellite TV rely on. This means that even if cables have less bandwidth than electromagnetic waves, cable TV companies can now deliver more channels over that bandwidth than satellite TV providers can. Of course satellite TV companies can expand their available bandwidth by launching more satellites so they can add more channels, but satellites are extremely expensive compared to the computers that cable TV companies have to add in order to make more channels available through switched digital video.

Perhaps more importantly, switched digital video can be used to provide video on demand options as well. Video on demand allows people to watch what they want, when they want, without having to record it ahead of time. All of this means that switched digital video translates into good things for cable TV. - 17564

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