I've heard that television broadcasts are going all-digital next February. Is that the same thing as being in high-definition?
A: Not exactly. High-definition television or HDTV refers both to a high quality broadcasting standard and the class of TV that you need in order watch those shows in their full resolution.
That's not going to change in February, when all major U.S. TV stations will stop broadcasting traditional analog signals and continue only with digital broadcasts.
HDTV broadcasts are one kind of digital broadcast, but there are others that aren't as high-end. Like today, many TV shows will still be broadcast in "standard definition" after the end of analog broadcasting on Feb. 17.
Still, even standard-definition digital broadcasts will provide better pictures than standard-definition analog broadcasts.
That's because digital transmissions are more efficient than analog and better able to strip out shadow images, static and interference. Know how running a vacuum cleaner near a TV can distort the image? That's far less likely to happen with digital TV.
Since they're more efficient, digital signals also allow stations to broadcast additional "side" channels using the same amount of spectrum.
Even today many stations are broadcasting digital side channels with supplemental programming such as weather reports, which you can see if you have a new TV equipped with a digital tuner.
Major TV networks broadcast much of their prime-time lineups today in high-definition, but you still need an HDTV set to see them in their full glory. Several cable channels such as ESPN also use high-definition.
Part of the confusion between digital and high-definition seems to be a result of the many references to DTV for digital television, while HDTV is often used as shorthand for high-definition TV.
"It's safe to say that all television will be DTV, but not all television will be HDTV," said Jay Adrick, the vice president of broadcast technology at Harris Corp., a major manufacturer of broadcasting equipment.
Unless your TV is brand-new and is equipped with a digital tuner, you'll need a converter box to watch over-the-air broadcasts after the changeover. In most cases, cable and satellite subscribers aren't affected.
Converter boxes are on sale now, generally for about $60, and the government is offering two coupons for $40 each to every household to defray the cost. You can order a coupon online at www.dtv2009.gov.
A main difference between standard and high-definition broadcasts comes down to how many lines are displayed in the picture. Standard-definition broadcasts and sets have 480 horizontal lines, and high-definition TV standards use 720 or 1,080 lines. You'll sometimes see these expressed as 720p or 1080i.
All high-definition broadcasts are in the widescreen, or 16:9 format. Standard-definition can be broadcast in widescreen or traditional 4:3 format.
HDTV sets have been steadily coming down in price, and more people have them. About 28 million HDTV sets were installed in U.S. households as of the last quarter of 2007, according to DisplaySearch, a retail research firm.