Full HDTV Facts

A popular topic in televisions nowadays is full HDTV (full high definition television). This is due to the full changeover of digital television (DTV) signal on June 12, 2009. With this transition complete, everyone has access to HDTV signal. However, not everyone has HD display because in order to get it, you must have an HDTV display television.

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.

The resolution of JDTV and full HDTV are what make them different from analogue TV. The full HDTV resolution is 1080i or 1080p. The standard HDTV has a resolution of 720i or 720p. The “p” stands for progressive scanning, meaning that the vertical scans are done at the same time instead of interlaced. With an aspect ratio of 16:9, the full HDTV has 1920 x 1080 pixels while the standard HDTV has 1520 x 720 pixels.

It seems that the full HDTV (1080p) would be the most desirable product for optimum resolution and viewing pleasure. However, on televisions smaller than 42 inches in size, the difference in the standard HDTV versus the full HDTV isn’t visible. For this reason, full HDTV isn’t available on smaller TVs. Only standard HDTV (720i or 720p) is available. Hence, a 42 inch screen television or larger is required if you wish to get the benefit of full HDTV.

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 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.

A note of caution, except for resolution, when comparing specifications many reviewers question their accuracy and their meaningfulness to your viewing experience. My advice is judge for your self. In conclusion, barring financial and/or physical restraints or simple preference for smaller TV size, full HDTV is the obvious choice. If striving for a home theatre experience, make sure your full HDTV is compatible with the entire system you are planning.