We've all heard a lot of talk from many sources about the conversion to to digital television (DTV). To make things even more confusing, High Definition Television (HDTV) comes into the mix. Because DTV and HDTV are often used interchangably, people often think they are one in the same. In fact, they're two different animals...sometimes.

The fact is, all HDTV is DTV, but not all DTV is HDTV. Digital television means just that: it's TV in a digital form instead of the analog video that we're all used to. DTV is the same resolution as analog TV, but it has the potential to be sharper with fewer image problems (such as ghosting or "snow") since it's an either all or nothing situation. With analog TV, you can still get a fuzzy image with a poor signal. With digital, a poor signal often means no image at all. However, if you get enough a digital signal to produce an image, it will look very good. An HDTV image will look even better.

HDTV is higher resolution than regular digital TV. In fact, HDTV contains several times the resolution of either analog or digital standard definition TV (SDTV). In addition, while digital TV may or may not be widescreen, native HDTV is always widescreen (16:9 aspect ratio). SDTV video (4:3 aspect ratio) shown on an HD channel will show either black or graphic pillar bars on either side or it will be stretched horizontally to fill the wider screen. Of course, older films converted to HD still contain higher resolution than SD video, but may be in the older academy aspect ratio (roughly 4:3). This means these older films may have bars on the sides since there were not originally shot widescreen. Films like "The Wizard of Oz" and "Citizen Kane" were shot in academy aspect ratio.

Digital cable and satellite advertise "digital quality". However, while the service is digital, most stations are not HD. In addition, you'll need an HDTV-capable TV and an HDTV converter box from your service provider. Standard digital cable and satellite services are not HD.

The local broadcast stations are converting to digital broadcasts, though they may or may not transmit HDTV. Cable stations are not required to go digital. In addition, this only affects the over-the-air (OTA) signal the stations transmits to those people who use antennas. This means you'll need a digital converter box or a digital TV if you get your TV via an antenna. Viewers who have cable or satellite will probably not notice any difference in their service and should be able to view TV with little or no change to their equipment. All viewers who wish to view HDTV via cable, satellite or OTA will need to have an HDTV set and many will need a separate converter box.