Digital broadcasters are not restricted to just sending a high-definition picture. They can still broadcast a standard-definition picture, but why would they want to do that? There's a very good reason. In the same amount of signal they can "multi-cast" four standard-definition pictures instead of only one high-definition picture.

Some broadcasters, including many PBS stations, are already planning to multi-cast four choices of programming during the day, and then switch to high-definition for prime-time. When you tune to your local Public Broadcasting station during the day, you may have a choice between children's programming, do-it-yourself shows, adult education, popular documentaries, or other programming. All from the same broadcaster.

Digital TV is going to offer us more choice, and it's going to make our viewing experience more interactive.

Enhanced TV