High Definition Television (HDTV) and other DTVs
August 22, 2007
Digital Television (DTV) has been replacing old analog TV world wide. Analog TV often suffer from problems like ’snow’ or ‘ghosting’ which occur when the signals are interrupted or weak. You see horizontal bars running over the screen or picture getting totally distorted. Similarly, digital TVs (DTV) that started to evolve with the onset of Standard Definition TV which uses video standards like NTSC, PAL and SECAM also had their own shortcomings as far as the picture quality is concerned.
Digital images are usually not susceptible to these problems, as the digital broadcast displays frozen image when transmission of signals is interrupted. The other advantages of DTV are better image quality, superior sound effects and their compatibility with numerous video inputs.
Again, DTVs are classified into three major types based on resolution or picture details that they are able to display.
They are as follows:
Standard Definition Televison (SDTV)
Enhanced Definition TV (EDTV)
High Definition TV (HDTV)
Standard Definition Television (SDTV)
Although SDTV provides better picture quality than standard analog television, its 480 lines of resolution is the lowest of the three types of DTVs. Definitely, they are superior to analog TV both in terms of picture and sound. However, in comparison with EDTV or HDTV, they lack some of the advanced features like wide aspect ratio and greater bandwidth.
Enhanced Definition Television (EDTV)
What distinguishes EDTV from SDTV is the progressive scan that an EDTV uses to produce display. Typically, 480p is the standard resolution of EDTV, which is also the resolution of a DVD. So, it is not necessary to mention that they are highly recommended for viewing DVDs to enjoy the best picture quality. Most low-end plasma TVs are often EDTV, as only larger, high-end plasma TVs come with HDTV compatibility. However, most LCD televisions, irrespective of screen size, come with HDTV resolution. Likewise, an EDTV can support both 4:3 aspect image and wider aspect image (16:9).
High Definition Television (HDTV)
HDTV is definitely the best of all DTVs, not only in terms of its higher resolution but also in terms of overall picture quality and its Dolby surround sound features. While 720p is its standard resolution, high end HDTVs can have higher resolutions like1080i and1080p. The true HDTV resolution (1080p) produces images of the highest resolution which is not at all possible on any other DTV. Usually HDTV signals use video compression, hence, they can store much more amount of visual data and can produce billions of natural colours.
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