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.
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.
One disadvantage is the power requirements in a plasma TV. The requirements can be as high as 500 watts. In addition, plasma TVs are traditionally heavier than LCD displays. However, the plasma can be mounted on a wall and the LCD display can’t.
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.
James Junior writes about panasonic full hd tv and led tvs
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