How does a TV signal get to you?

Many people in the United States hook their TVs up to a cable TV system to get a signal. A typical cable system might offer 100 channels or more. How do all the channels get to you? Every TV channel creates its own signal. So, for example, the Discovery Channel company decides what it will send out on its channel. It beams its programs up to a satellite in space, and the satellite immediately sends those signals back down to Earth.

In your community, there is an office for the cable TV system. This office has dozens of satellite antennas on the ground. One antenna picks up the satellite signal from the Discovery channel. Other antennas pick up all the other stations. The cable TV company takes all the signals from all the channels, merges them together, and puts them on the cable. From the cable TV office, there are wires that spread out to every home using cable TV in the community. What comes into most houses is a "coaxial cable" – a special wire that has a protective outer layer to cut down on interference. Some systems also use fiber optic cables to carry the signals into your home.

Another common way to get TV signals is through satellite TV. This looks a lot like a cable company, but it doesn't use any wires. The satellite TV company gets all the signals from all the TV stations, just like a cable TV company does. Then the satellite TV company merges all the signals together and sends them back up to another satellite that the satellite TV company owns. Then this satellite sends all the signals back down to Earth. Each home that uses Satellite TV has a small satellite antenna that picks up the signals from this satellite and sends them to the TV.

TV in the Future Today we have HDTV. With HDTV, there are two million very clear pixels on the screen. There are digital cable and digital satellite systems bringing shows to these HDTVs. And Blu-ray disks make movies available in high resolution. But what happens in the future? Engineers are already working on advanced HDTV systems with eight million pixels on the screen. These TVs already exist, but right now they are incredibly expensive. We don't really have anything to display on them either, although a new crop of cameras will solve that problem. But TV might go in another direction, and switch over to the Internet. Places like NetFlix are already delivering lots of movies over the Internet. Many TV channels make their programs available on the Internet. YouTube is incredibly popular and holds millions of videos on the Internet. And the Internet lets you watch whatever you want whenever you want. On a digital cable system, there are just a few hundred channels. On the Internet, there can be millions, and anyone can produce a video. This may be the future of television.