Tuesday, March 07, 2006
Before the advent of progressive scan, conventional TV utilized analog signals through interlaced scanning. The two main kinds of interlaced scan technologies, NTSC and PAL, operated to deliver to the typical display of video images. The standard in Canada, Mexico and the United States, as well as some areas of South America, NTSC technology is founded on the following: a 525-line with 60 fields/30 frames every second and a 60 HZ system for the transfer and depiction of images. Frames are scanned individually, read in two separate groups of 262 lines each. The lines then coalesce to present an image frame that has 525 lines.
PAL is used internationally for analog signal transmission in TV. Its technology utilizes a 625 line, with 50 fields/25 frames each second and a 50 HZ system. The video signal is interlaced into two separate groups, each made up of 312 lines. PAL is superior to NTSC due to the higher number of scan lines involved. The color quality is also better. PAL's number of frames and the rate at which it produces them is similar to a movie.
Progressive scan technology was created to improve video display. Its rise coincided with the development of computers. Standard television monitors were initially used with computers, but these monitors did not have adequate video capabilities because they used interlacing. Progressive scanning was created to remedy the situation. In progressive scanning, the lines of an image are scanned separately in the order they appear, whereas with interlacing, lines are scanned alternately. Progressive scanning thus produces a more consistent, even picture, one with less of a tendency to fade in and out, and one that displays crisp, vivid detail.
Because it represents such an improvement, progressive scan is widely used now, in DVDs and in high definition television (HDTV). The application of the technology is also seen in digital television (DTV). DTV transmits in 480 lines, progressively. HDTV broadcasts in 720 lines progressively.
For viewers to get progressive scan, all home theater equipment must have progressive scan capabilities. This means the TV and the cable or satellite receiver, as well as the DVD player, must be progressive scan-ready. Most of these components have progressive scan ouptuts. They also have interfaces that can handle the transmission of progressive scan signals to the TV.
Most older model televisions do not come equipped with inputs for progressive scan-ready equipment. In fact, if you buy a DVD player that's progressive scan, and you're TV isn't progressive scan-ready, then you won't benefit from the technology at all.