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All things TV

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2009
30
Sep

Full HDTV Television

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by James Junior

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.

HDTV and full HDTV are different from analogue TV due to the resolution of each. The standard HDTV has a resolution of 720i or 720p while a full HDTV has a resolution of 1080i or 1080p. The “p” instead of the “i” stands for progressive scanning. This means that the vertical scans are done simultaneously. Using a 16:9 aspect ratio, the standard HDTV is has 1520 x 720 pixels and the full HDTV has 1920 x 1080 pixels.

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.

However, the power requirements for a plasma TV can be as high as 500 watts. Also, plasma televisions are heavier than LCDs; however, plasma screens can be mounted on the wall.

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.

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.

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