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).
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 1920x1080 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 screens have a broad range in color, are very bright, and can have very large screens. Display screens of full HDTV plasma TVs can be up to 58 inches in size. Since the display panel is only about 2.5 inches thick, the televisions are only about 4 to 6 inches thick. Though there are claims of contrast ratios as high as 100K in plasma TVs, the highest contrast currently available in stores is 30K. The response time is .001 milliseconds while the refresh frequencies are 600 Hz. The advantages of a plasma TV over an LCD are that the screen has a better color reproduction and also has a wider viewing angle. Because of the fast response time, plasma TVs are great for viewing fast moving film such as sports.
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 as plasma HDTV screens. The effect of a slower response time in LCD TVs could possibly be ghosting on fast moving images. However the refresh rates have decreased to around 2 milliseconds with 240 Hz. The contrast ratios have also been enhanced to 30K. The biggest advantage of the HDTV LCD televisions is price since they 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. - 32388
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 1920x1080 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 screens have a broad range in color, are very bright, and can have very large screens. Display screens of full HDTV plasma TVs can be up to 58 inches in size. Since the display panel is only about 2.5 inches thick, the televisions are only about 4 to 6 inches thick. Though there are claims of contrast ratios as high as 100K in plasma TVs, the highest contrast currently available in stores is 30K. The response time is .001 milliseconds while the refresh frequencies are 600 Hz. The advantages of a plasma TV over an LCD are that the screen has a better color reproduction and also has a wider viewing angle. Because of the fast response time, plasma TVs are great for viewing fast moving film such as sports.
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 as plasma HDTV screens. The effect of a slower response time in LCD TVs could possibly be ghosting on fast moving images. However the refresh rates have decreased to around 2 milliseconds with 240 Hz. The contrast ratios have also been enhanced to 30K. The biggest advantage of the HDTV LCD televisions is price since they 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. - 32388
