Here's a nice set of links about HDTV...
web-star.com
And a nice primer...
ask.yahoo.com
We knew that HDTV was an acronym for high-definition television and that HDTV sets seem a bit expensive. Luckily, HowStuffWorks.com offers a detailed explanation of HDTV and how it works. The site also includes general information on television and examines digital TV, the basis for HDTV.
A conventional, analog TV uses a cathode ray tube to deliver images to you, which limits the quality of the image. The screen resolution of an analog TV is about 512x400 pixels. HDTV uses a digital display, like your computer monitor, and the screen resolution is at least 1280x720 pixels, which is comparable to a high-end computer display. A higher screen resolution means a crisper, clearer picture.
In addition to dramatically improved picture quality, HDTV also offers a wider format. This makes an HDTV image more like a movie-screen image. The width-to-height ratio -- called the aspect ratio -- of HDTV is 16:9. Analog TV has an aspect ratio of only 4:3.
The difference in aspect ratio is most noticeable when watching theatrical movies on TV. For analog TV, the movie must be cut down in a process called "pan and scan," in which a part of every scene is deleted to fit the lower aspect ratio. The only way to see the entire movie scene on an analog TV is to "letterbox" the movie. In letterboxing, the full movie is shown in the middle of the screen with black bars at the top and bottom. HDTV eliminates letterboxing and allows you to see the complete movie on the whole TV screen.
The Federal Communications Commission (FCC) agrees with TV networks and manufacturers that digital television, including HDTV, should be the new standard for broadcasting. As of May 1999, the FCC requires the top TV networks to broadcast a digital signal in the 10 biggest markets, which represent 30 percent of TV households in the U.S. The networks plan to expand digital coverage and phase out analog TV broadcasts entirely by the end of 2006.
The HDTV Galaxy FAQ addresses a major question raised by HDTV -- why do we still have analog TVs? TV stations and media production companies have to upgrade equipment in order to produce HDTV programming, a slow and costly process. For this reason, the FCC created a transition plan slated to end in 2006. Also, HDTV sets are currently more expensive than analog TVs. It is expected that when consumer demand for the sets increases, production will also increase. And, and as was the case with color TVs, VCRs, and even DVD players, the prices will eventually fall. |
