A PRIMER ON THE NEW TELEVISION

By Royal Van Horn

Illustration © 2003 by Mario Noche

I DON'T LIKE being confused, so I set out to get unconfused about HDTV (high-definition television), liquid crystal displays (LCD), and plasma television sets. It took me several hours to glean the information for this column, and I pass it along in the hope that it will save readers some time.

If you are happy with your old TV and have not been in a consumer electronics store lately, then all is well, and my advice is, don't go. I recently had the opportunity to attend the large audio/video convention called InfoComm. InfoComm showcases all the new gear - a lot of which is supersized. The new televisions at InfoComm were so stunning that I thought I could reach into the picture and touch things. Even if you are not in the market for one of these splendid new televisions, I recommend you clip and save this column for when you are. In the meantime, stay out of the store!

For over 50 years, the U.S. television standard has been the National Television System Commission or NTSC. NTSC television at best has approximately 480 horizontal lines of resolution and stereo audio. Videocassette tapes have about half of this resolution. To accommodate relatively slow frame rates (30 frames per second), NTSC television signals are "interlaced." An interlaced signal consists of two fields, the odd-numbered lines and the even-numbered lines, which are displayed sequentially in 1/60th of a second each. This is too fast for the human eye to notice. Sorry about the jargon. Just remember 480i.

There are a number of new HDTV standards, but by far the most common are 720p and 1080i. The numbers indicate the number of vertical pixels. The "p" stands for progressive scan, which means the frame or image is drawn all at once. Both these new standards offer about four times the resolution of the older 480i. Of course, 1080 is not four times 480, but remember we are dealing with improvement in both the vertical and horizontal resolution. It is desirable to purchase an HDTV that can display all three resolutions mentioned here.

The NTSC or 480i screen was nearly square (an aspect ratio of 4:3). Most HDTVs are wide screens that look more like a movie screen (an aspect ratio of 16:9). The future of television is wide screen; the HDTV specification is wide screen. How soon you should buy a wide screen, however, is a tough decision. If you watch a lot of movies, then a wide screen makes sense. If you watch a wide-screen movie on a regular 4:3 television, you see what is called "letter boxing." There is a black bar at the top and bottom of the picture. Conversely, if you have a wide-screen television and watch regular programming designed for a 4:3 screen, the black bars are at the side of the screen. Personally, I think letter boxing is the less desirable of the two options, but it's a matter of taste. Some new televisions will let you stretch the picture one way or another to fill the screen, but it sure makes people look funny.

I should mention that DVDs cannot give you an HDTV-quality picture. The picture is good, and it looks really good on an HDTV television. But it is not quite up to HDTV quality. For a true HDTV picture, you have three practical options: a digital HDTV antenna, a satellite receiver, or a cable company that is distributing HDTV programming. All major television networks except Fox now offer some of their programming in HDTV. How much HDTV programming you can actually get depends on your location, your particular cable company, and so on. You will need to do a little research to learn just how much HDTV programming is available to you. Both satellite and cable television providers offer "digital video," but digital video is not the same as HDTV. All HDTV is digital, but the opposite is not true.

The variety of different technologies used in today's televisions is bewildering. The list includes the familiar CRT or tube-type television, which is now sometimes called direct view; front- and rear-screen-projection television; LCD; and plasma flat panels. There are several other technologies used or under development, but they are much less common than these four. The new LCD and plasma flat-panel televisions are just a few inches thick and are becoming much more affordable than they were even a year or two ago. LCD and plasma flat panels look a lot alike, but the technologies are radically different and have much different strengths and weaknesses.

Before you think about purchasing an LCD or a flat-panel television, you should consider the following details. According to many experts, it's tough to build large LCD screens of over 42 inches, and it's tough to build plasma panels that are less than 42 inches. Nearly all flat panels under 36 inches wide are LCD panels, and all panels over 48 inches are plasmas. Thus the screen size you select may be the determining factor in which technology you purchase. Another significant difference between the technologies is that plasma panels run warm and need cooling fans. LCD panels run cool and are usually silent. This fact should be taken into consideration if a plasma panel is to be placed in an enclosed entertainment center. Setting a plasma panel on a table top or hanging one on a wall is not a problem.

Another significant disadvantage to plasma panels is "burn-in." A panel with burn-in has a ghost of the burned-in image that is always visible. Burn-in can happen when you pause a picture too long. For example, if you let an on-screen menu stay on the screen for as little as a minute, you might have ghosting. Owners of plasma panels seem to learn to be careful, but I wouldn't want children to operate one. It is technically possible to build a plasma panel that has protective circuitry to eliminate the danger of burn-in, but apparently many of today's panels do not have such protection.

Many LCD panels have a weakness in that they do not have a high enough contrast ratio. Contrast ratio is the difference between light and dark. I have seen specifications on some LCD panels of as little as 400 to 1, while 1,000 to 1 should be the desirable target. Shop carefully. Despite this drawback, I believe LCD panels are a wiser purchase unless you want a very large screen.

The biggest problem plaguing the move to HDTV is the "set-top box" (STB) problem. Nearly all of today's HDTVs are "HDTV ready." In reality, they are just display devices that do not have a channel tuner, so you have to buy an external one that costs from $200 to $500 if you want to watch network television. When an HDTV set has an internal channel tuner, it is usually an analog one that cannot process a true HDTV signal. Matters could get even worse, since you might need both a satellite or cable box and an HDTV tuner. Furthermore, you probably need to buy the same brand name HDTV and tuner to be sure that one will connect to the other. I understand that in the next few months several manufacturers will start providing HDTVs with internal HDTV tuners. It might be wise to wait until this happens. A second possibility is that satellite and cable companies will begin offering STBs that do everything well. If these problems sound discouraging, just remember that even regular television displayed on an HDTV still looks several times better than the television you are probably used to watching.

No discussion of HDTV would be complete without mentioning audio. NTSC or 480i television has two-channel stereo; HDTV has 5.1-channel Dolby digital surround sound. The five channels are left front, right front, center, right rear, and left rear. The "point one" stands for the sub-woofer channel, so there really are six discrete channels. Of course, to enjoy the great sound, you will need a stereo receiver or surround-sound processor and quite a few speakers. Television receivers, either old ones or new ones, rarely have good sound, so upgrading your stereo system is a good idea even if you are not switching to HDTV anytime soon.

Another thing to consider when purchasing an LCD or a plasma flat-panel television is viewing angle. Viewing angle is a measure of how far to the side of the panel you can be and still see the picture clearly. A viewing angle of 160 degrees is great, but many panels have numbers that are a lot lower. You can easily judge the viewing angle of a flat panel in the showroom - just don't forget to do so.

I hope the above discussion helps demystify HDTV and that it wasn't too complicated. HDTV is the new U.S. standard, and all of us will eventually be switching to it. The Federal Communications Commission has set a target date of 2006, at which time every television provider in the U.S. must transmit HDTV. (Many experts think 2006 is too optimistic a date.) At that time, providers will be free to stop transmitting an NTSC or 480i signal. If you want to study HDTV and related issues further, I recommend the websites of Electronic House (www.electronichouse.com) and Sound & Vision (http://webcenter.soundandvision.netscape.com).

ON A different topic, Wired magazine recently published "How U.S. Schools Rate in Cyber Liberties" (www.wired.com/wired/archive/11.06/start.html?pg=3). This survey of the 50 top research universities looked at campus policies regarding network freedom and privacy. The best university was MIT, with a policy that "grants root access to anyone who asks. Runs an anonymous remailer and PGP key server." At the other end of the scale, in almost last place, was Tulane, which "regards logging onto the network as a student's consent to look at any file, including e-mail." The top five universities in the Wired survey were MIT, Cornell, Vanderbilt, the University of Michigan, and Carnegie Mellon. The worst five were Columbia, Tulane, Tufts, the University of North Carolina at Chapel Hill, and, surprisingly, the University of California at Berkeley. If you use your college's or school's network regularly, you might want to check into its policies.

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