Video Displays

To understand how advances are being made in video display technology, it is first important for you to understand the basics of video displays. The basic United States signal for broadcasting is named NTSC, and it is comprised of a signal that can generate one picture for each 1/30th second. After this has occurred, the signal for the video will be scanned on a CRT television through the use of 480 lines which are horizontal and visible.

In order for this to work, the NTSC signal will need to scan all the lines which are even numbered first, and then it will need to scan all the lines which are odd numbered. Each must be done in 1/60th of a second. What results from this is called the 480 interlaced picture, which will occur for every 1/30th second. I know this may sound a bit complicated to sum, but you can remember it easily be keeping in mind that it is called 480i. This is for video displays that are used within the United States.

The 480i picture has been very good for smaller televisions that are no more than twenty inches. However, you will run into problems when you attempt to use 480i with images that are bigger. The reason for this is because the scan lines will begin to become far too visible, and this will always occur when using 480i for screens larger than 20 inches. Over the last few years, a number of home theater experts have begun using scan doublers to handle the video signal and increase the speed of the scanning process.

This is done so that the lines in the video displays will disappear. This is especially useful on CRT video projectors which are very high in quality. The video image will be extremely high in quality, and at this point it can even rival film, particularly if the video source is high in quality. At this time, it is not yet possible to apply a scan doubler to a standard 480i television, because it won't be able to scan quickly enough. In the past, scan doubling tools were highly expensive and could be as much as $60,000
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The good news is that the cost of these video displays tools have fallen over the last few years. High definition has been largely responsible for bringing a revolution to television broadcasting.

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