High-definition television is a form of digital TV. Other forms of digital TV are enhanced-definition TV (EDTV) and standard-definition TV (SDTV). All these sets can receive digital TV channels, which will become the standard in the next few years. However, only HDTVs can receive high-definition programming

HDTV has a resolution of at least 720p. Other resolutions include 1080i and 1080p (the letters stand for “progressive” and “interlaced,” which are ways the image is shown on the screen). Most sets will convert a higher or lower resolution to their formats.

Resolutions expressed in numbers like 1280 x 768 refer to the number of pixels across by the number of pixels top to bottom on a screen. The second number must be 720 or higher for the set to be an HDTV.

EDTV has a resolution of 480 to 720. SDTV is below 480. Do yourself a favor: Spend more and buy the HDTV.

All HDTV images are widescreen, or 16:9, meaning the shape of the screen is 16 units across to 9 units high. We don’t know why they have to make this so complicated.

Many HDTVs are “integrated,” meaning the digital tuner required to receive a digital broadcast is built in. Some even have cable tuners built in, and some “digital-cable ready” sets accept digital Cable Cards that slide into a slot to act as a cable tuner. Sets without integrated tuners may be marketed as “HDTV ready,” “HDTV compatible,” or “HDTV Monitor.” If you’re going to get HDTV off a separate cable or satellite box, you won’t need a built-in tuner.

Digital cable is NOT digital TV. It is only the way the cable company transports the signal.

By Steven Castle, senior editor for Electronic House magazine. To see more articles from the editors of Electronic House magazine about the connected home visit www.electronichouse.com.

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