HD Tivo

High-definition television, or HDTV, has been around for several years now. The screens look more like movie screens than television sets, and provide life-like sound and picture. They are also extremely expensive, though the price has fallen as the novelty of the device begins to wear off.

With regular, analog TV, a six MHz signal carries the color information for each line of the picture. In the United States, there are 525 scan lines, each of which is refreshed every one-thirtieth of a second. Most satellite systems, as well as DVDs, use a digital encoder that provides a much clearer picture. In such systems, the digital format is converted to analog.

HDTV, since it uses a digital format, does not require this conversion, and thus provides a much clearer picture. Most HDTV sets use 720 or 1080 lines of resolution, meaning the picture is one-and-a-half to two times as sharp as analog. In the coming years, broadcasters will be required by law to provide an HD signal, though most have already done so.

TiVo, though this will change in the coming months, has been partnering with DirecTV, a satellite television company. The digital signal coming into the television is recorded on a digital recorder--the TiVo. The all-digital environment is what makes the playback, rewinding, and fast-forwarding work so smoothly. Though DirecTV will be going its own way, marketing a competitor to TiVo's service in the coming months, TiVo will work with all digital signals, meaning the devices will still be as useful as before.