Since the federal regulation of mandatory DTV (digital television) signal, the subject of full HDTV (full high definition television) has become a more popular topic of discussion and has become more of an interest to the public. With the digital changeover, now everyone has access to HDTV signal. However, an HDTV display is still necessary in order to view high definition no matter what type of signal you have (cable, antenna, or satellite).
For HDTV, resolution is the key word, defining how detailed an image can be displayed without blurring. Those who opted for the HD converter box are still viewing a picture on an analogue CRT screen .NTSC-analogue TV resolution is defined as 480i. The 'i' means interlaced. This results from the TV camera having 480 horizontal lines of resolution while the CRT tube has only 240 lines available. So every other line of the 480 is simultaneously scanned for 1/60th of a second then the remaining lines are scanned. Hence, the TV signal is "interlaced" giving the appearance of more vertical resolution. With an aspect ratio of 4:3 (width x height), the analogue television resolution can be described 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 1920x1080 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.
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. - 29967
For HDTV, resolution is the key word, defining how detailed an image can be displayed without blurring. Those who opted for the HD converter box are still viewing a picture on an analogue CRT screen .NTSC-analogue TV resolution is defined as 480i. The 'i' means interlaced. This results from the TV camera having 480 horizontal lines of resolution while the CRT tube has only 240 lines available. So every other line of the 480 is simultaneously scanned for 1/60th of a second then the remaining lines are scanned. Hence, the TV signal is "interlaced" giving the appearance of more vertical resolution. With an aspect ratio of 4:3 (width x height), the analogue television resolution can be described 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 1920x1080 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.
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. - 29967
