The High Definition TV Revolution

Full HD TV (full high definition television) has become a topic of interest to more people since the final crossover to DTV (digital television) on June 12, 2009. What has changed, at least in theory, is that everyone now has access to HDTV signals. However, if one wishes to view the signal in HD it will require an HDTV display regardless of signal source (antenna, cable, or satellite).

The main advantage and interest in regards to HDTV is the high resolution. If you chose to go with an HD converter box, your television still has an analogue picture on a CRT screen. The resolution of an NTSC-analogue television is called 480i; the “i” meaning “interlaced”. This means that since there are only 240 horizontal lines available in the CRT tube and the TV camera has 480 lines, every other line is scanned at the same time for 1/60th of a second. Then the other lines are scanned. So, to portray a more vertical resolution, the TV signal is interlaced. With an aspect ratio of 4:3, the analogue TV resolution is 640 x 480i.

So how do HDTV and full HDTV differ from analogue TV? Certainly the most obvious feature is the resolution. Standard HDTV has a resolution of 720i or 720p and full HDTV has 1080i or 1080p. The ‘p’ signifies progressive scanning versus interlaced, i.e. all the vertical scans are done at the same time. With a 16:9 aspect ratio in HDTV this results in 1520 x 720 pixels for standard HDTV and 1920×1080 pixels for full HDTV.

The full HDTV is the product that is most favourable, but on TVS with a smaller screen than 42 inches, the difference in the resolution between the standard and full HDTVs isn’t noticeable. Therefore, any TV that has a smaller screen than 42 inches is only available in standard HDTV. So, if you want to have full HDTV, you will need to purchase a 42 inch HDTV or larger.

Three choices of screen technologies are available for full HDTV. These are rear projection HDTV, full HD plasma TV and full HD LCD TV. Rear projection HDTVs are still available but this technology appears on the decline with many manufactures dropping out of the market. Therefore, one is left with full HD plasma TV and full HD LCD TV to choose between. Since a resolution of 1080p is assumed, other factors affecting image quality to consider are response time and refresh rate, contrast ratio and color reproduction.

Full HD plasma displays are bright, have a wide color range, and can be produced in fairly large sizes, up to 58 inches is commercially available. Because the display panel is only about 6 cm (2.5 inches) thick, the overall thickness is about 4 to 6 inches. Contrast ratios are as high as 50K to 100K are claimed but, in reality, the highest available in stores is 30K with response times at 0.001 milliseconds and refresh frequencies of 600 Hz. Fast response times make plasma TV’s ideal for fast motion video (films or sports viewing). Plasma screens also are said to have better color reproduction than LCDs and to have a wider viewing angle.

Of course full HDTV plasma is not perfect. The power requirements can be as high as 500 watts for some large screen versions and because the screen is made of glass, glare can be a problem. Plasma displays are heavier compared to their LCD counterparts but can be wall mounted.

Full HDTV LCD displays have the same resolution as plasma full HDTV displays, but the LCD displays have a slower response time (2 milliseconds). This could result in ghosting during fast moving images. The refresh frequency of an LCD display screen is 240 Hz, but the contrast ratio has been improved so that it’s the same as the plasma screen (30K). Though there are some differences in response time and refresh frequencies, LCD TVs are less expensive than plasmas.

Other than resolution, the other features of the two full HDTV options are more up to interpretation and the desire of the consumer. Ultimately, full HDTV is the best choice, taking into consideration the extra cost. However, be careful to make sure that if you’re looking into an entire home theatre that your full HDTV is compatible with the system.

You can leave a response, or trackback from your own site.

7 Responses to “The High Definition TV Revolution”

  1. [...] simplify things there are two types of televisions – older standard definition TVs (SDTV) and High Definition TVs. SDTVs display at 480i or 576i and HDTVs display at 720p, 1080i and 1080p. An SDTV television [...]

  2. [...] manufacturers in the world today. It consistently brings us new innovations in the world of high definition TV and its range of televisions come with quality and style guaranteed. It is therefore no surprise [...]

  3. [...] High Definition TV (HDTV) is a far cry from the grainy black and white television sets of the 1950’s. With the addition of free wireless hotspots and the availability of wireless broadband internet services, it is possible to watch HDTV online nearly anywhere at almost anytime. The days of rushing home to catch a television show is a thing of the past, as major television networks post HDTV shows online for viewers to watch at their leisure. [...]

  4. [...] frequent subject in the world of television is ‘full high definition TV’. Full HD TV’s prominence is dues to the changeover from analogue to digital television on [...]

  5. [...] High Definition TV has been one of the most high impact technologies that have made an appearance in the last decade. [...]

  6. [...] older CRT televisions were capable 576 lines but HD televisions are capable of up to 1080 lines. High Definition TV or HD TV – The term HDTV is a general term that covers more than one format or specification of [...]

  7. [...] of all three is of course the one I have at home now which is DirecTV. Second to none in the High Definition TV category. They have more HD channels than Dish Network and way more than Comcast. In fact that was [...]

Leave a Reply

Subscribe to RSS Feed