Full HDTV Facts
Full HDTV (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).
When talking about HDTV, the quality of the picture (or high resolution) is the main point. Anyone who chose to purchase or obtain an HD converter box still has an analogue picture on a CRT screen. The resolution of an NTSC-analogue TV described as 480i. The “i” in the description refers to the word “interlaced”. The reason why is because the CRT tube in the analogue television only 240 horizontal lines available, but the television camera has 480 lines. Therefore, in order to present the look of a more vertical resolution, the television signal is interlaced. If you consider the aspect ratio of 4:3, using basic mathematics, you can see why the analogue TV resolution can be depicted as 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’20×1080 pixels for full HDTV.
Full HDTV, 1080p, would seem the product of choice; however, for a TV smaller than 42 inches the difference between standard and full HDTV cannot be seen. Consequently, these smaller TV’s are available only in standard HDTV, either 720i or 720p. To enjoy full HDTV a 42 inch or larger screen is necessary.
There are currently three options in screen technology for full HDTV: rear projection HDTV, full HD plasma, and full HD LCD TV. Though rear projection televisions are still available, the demand and popularity of them seems to be decreasing. For that reason, many manufacturers aren’t even making them anymore. Therefore, it’s advised to choose between the two remaining options. Other things to consider when choosing a new television are response time, the contrast ratio, and color reproduction qualities.
Full HDTV 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 LCDs have the same resolution, 1080p, as plasma HDTV. Initially, slow response times in LCD sets could result in ghosting on fast-moving images. However, refresh rates have decreased to about 2 ms with a 240Hz refresh rate. The contrast ratios have also been improved to 30K. Full HDTV LCD’s are less expensive for the high-end systems necessary for full HDTV.
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.
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