What Is HDTV? > Digital TV
Televisions (the combination of a display and a receiver) in the digital world are known as DTV's. DTV's come in three levels of performance SD for standard definition, ED for enhanced definition, and HD for high definition. All the DTV's on the market today can receive all DTV signals, and the TV adjusts the signal to match the performance level of the display. In other words, a HD signal can be received, and converted to a lower performance signal to display on a lower performance display, such as an EDTV explained below. The following is the accepted industry names for the three levels of DTV's:
TVs that receive all DTV broadcasts and display 480 interlaced lines of resolution presented in 4:3 aspect ratio (today's square-shaped analog TVs). This is the same resolution (picture detail) as today's analog TV systems.
TVs that receive all DTV broadcasts and display less than 720 lines (for example, 480p) are called EDTVs - "enhanced definition." The television's screen shape may be widescreen (16:9) or standard (4:3), but the image displayed is widescreen. This is the same resolution as today's DVDs.
TV's that receive all DTV broadcasts, and display 720 or more progressive lines (or rows of pixels measured vertically) are called "high definition." This includes 720p, 1080i, and 1080p. The television's screen shape may be widescreen or standard (4:3), but the image displayed is widescreen (16:9). HDTV is the fastest-growing segment in the market, and delivers the best performance - matching the quality of most broadcaster's signals.
