Associated Installations Inc. Established 1956

Difference Between Digital TV and HDTV

Q:Digital TV vs. HDTV, which is better?

A: A digital picture is usually a better picture, but not necessarily High Definition. A High Definition picture is digital and must be capable of displaying a minimum of 720 lines of vertical resolution.

All HDTV is digital, but not all Digital TV is necessarily HDTV. The same bandwidth for digital TV broadcasting can either used to supply a video signal (or several) and other services, or can be used to transmit a single HDTV signal.

The practical use of DTV has developed 3 standards which are: 480p, 720p, and 1080i.

480p
If you have a progressive scan DVD player and TV, you are familiar with 480p (480 lines of resolution, scanned progressively). 480p is similar to the same resolution of standard broadcast TV (and is referred to as SDTV or Standard Definition Television), but the image is scanned progressively, rather than in alternate fields. 480p does provide an excellent picture (especially on smaller 20-27" screens). It is much more film-like than standard cable or even standard DVD output, but it only provides half the potential video quality of an HDTV picture, therefore its effectiveness is lost on larger screen sets. Although 480p is part of the approved DTV broadcasting scheme, it is not HDTV. This standard was included as one of the DTV broadcasting standards to provide broadcasters the option of providing multiple channels of programming in the same bandwidth as a single HDTV signal. In other words, 480p is just more of what we already have with only a slight increase in image quality.
 

720p
720p (720 lines of resolution scanned progressively) is also a digital TV format, but it is also considered as one of the HDTV standards. As such, ABC, and now FOX, have committed to 720p as their HDTV broadcasting standard. Not only does 720p provide a very smooth, film-like image due to its progressive scan formula, but image detail is at least 30% sharper than 480p. As a result, 720p provides an acceptable image upgrade that is visible on both medium (32"- 36") size screens as well as larger screen sets. Also, even though 720p is considered high-definition, it takes up less bandwidth than 1080i, which is covered next.

1080i
1080i (1,080 lines of resolution scanned in alternate fields consisting of 540 lines each) is the most commonly used HDTV format, and has been adopted by PBS, NBC, and CBS (as well as satellite programmers HDNet, Showtime, and HBO through special feeds) as their HDTV broadcast standard. Although there is still debate as to whether it is that much better than 720p in the actual perception of the viewer, technically, 1080i provides the most detailed image of all the 18 approved DTV broadcast standards. On the one hand the visual impact of 1080i is lost on smaller screen sets (below 36"). However, with the increasing amount of large screen projection sets and custom front projection home theater setups, 1080i provides the detail needed for such large images.

Two drawbacks to 1080i are:

  1. It takes up the most bandwidth of all the DTV broadcast formats.
  2. It is an interlaced signal, which means that the displayed image is made up of lines that are scanned alternately instead of progressively as in 480p and 720p.

 
 
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Associated Installations of New Jersey (NJ) are installers of high end stereo and audio equipment. We offer the uncompromising audiophile and videophile the best money can buy in plasma hdtv, lcd hdtv, stereo speakers as well as rear projection hdtv. Audio video electronics with surround sound and consumer electronics such as amplifiers, audio components, integrated amps and more. Want a home theater? Let Associated Installations find the exact home theater system for your budget and space and still compliment your home to perfection. Whether it is your favorite movie or a sporting event or, an expert installed home theater system from Associated Installations will give you that extra special television experience. The Associated Installations web site was designed by Bower Web Solutions, Inc.