Analog vs. Digital

When considering TV types, there is a big distinction between analog and digital. In CRTs, you'll notice a big price difference between the two. A digital direct-view TV will have much greater resolution than its analog counterpart. Most digital TVs can display progressive-scan DVDs (480p) and HDTV (usually 1080i) at full resolution. Analog sets cannot.

Analog TVs send a signal telling the television's electron gun how to "paint" lines on the screen. The problem is that the signal degrades in transmission, affecting the amount of fine detail in the image. Digital sets send this same information in bit streams (lines of data made up of ones and zeroes). The advantage is that these digital signals do not degrade, so the picture is much better on a digital set.

You should also consider the source. No matter how much money you spend on a TV, the picture will only be as good as the source signal it receives. For instance, a DVD will look better on a low-end television than an analog broadcast antenna signal will look on a high-end HDTV. That is because the quality of the digital signal sent to the analog set is far superior to the analog signal sent to the digital HDTV.

Sources break down like this:

Type
Rating
Analog Good
Analog cable Better
Digital cable, Digital satellite Best

The key when thinking about sources is to match the right TV with the source available to you. For more details on each, check out How Cable Television Works, How Satellite TV Works, and How Digital Television Works.

Analog signals received on an analog set will display standard-definition TV and cable with a resolution you're probably used to seeing. A digital cable signal (like DirecTV or Dish Network) can be displayed on an analog TV, but it will lose its quality in the conversion from digital to analog.

As of June 2006, all new TV sets 25 inches or larger must be DTV-ready. As of March 2007, the requirement expands to include all new TVs 13 inches or larger.

Digital signals on a digital TV (DTV) will allow you to watch digital broadcasts and progressive-scan DVDs at their full quality. In addition, you will be able to watch most hi-def broadcasts. Enhanced-definition TVs (like plasma TVs) will also benefit from a digital source, but they won't have enough resolution to do HDTV broadcasts justice.

Hi-def broadcast sources will look best when viewed on an HDTV. Here's a breakdown of source/display combinations:

Combination
Result
Analog source to analog TV Analog picture (good)
Digital Source to analog TV Analog picture (better)
Digital source to digital TV Digital picture (best)