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with the EPB's HDTV! Click for more information... |
Also, a weaker analog signal can cause "snowy" pictures - something with which those of us who remember the days before EPB cable TV are too familiar. Digital TV signals are made up of coded instructions - the same "ones and zeros" that make your computer work, and give life to your CD's and DVD's. Your receiver isn't concerned with the signal strength, or what conditions exist between you and the transmitter. As long as the signal gets to the receiver, it can read the code and reproduce a near-perfect picture. With digital broadcasting, bad reception is a thing of the past. One reason cable TV caught on is because it delivers clear TV pictures without regard to the viewer's location. Digital eliminates "snow" and "ghosting" caused by the weak signals from distant or blocked transmitting towers.
Both digital and analog TV signals get weaker the farther they travel away from the transmitting tower. On an analog TV, the picture slowly deteriorates from bad to worse for more distant receivers. However, the picture on a digital set will stay perfect until the signal becomes too weak for the receiver to distinguish between a 1 and a 0, at which point the image disappears completely. The bottom line ... you either receive a 100% perfect quality picture, or nothing at all.
Images viewed on TV screens are made up of small picture elements known as "pixels." Each of these pixels is made up of three, closely spaced dots of color - red, blue and green. Combined together on the TV's screen and viewed from a distance, the colors are seen as one. On traditional TV's, 256 levels of intensity are possible for each of the three colors. The result is a range of 16.8 million colors. The pixels in the analog system are slightly taller than their width. Get up close to an analog screen - especially the larger projection sets - and you can easily see the red, blue and green rectangles. This is why distortion is sometimes seen on traditional TV's.
The pixels in HDTV sets are square; they are also smaller, and spaced closer together. There can be (4 ½) HDTV pixels in the same space that a single NTSC pixel requires. The result is that High-Definition-Television can display at least 4 ½ times more detail than a regular analog TV.
Digital TV's (16:9) wide-screen is approximately 1/3 larger than a comparable (4:3) set. The 16:9 wide-screen aspect ratio is the standard for Digital HDTV (because much more information can be displayed on the screen). Actually, the 4:3 aspect ratio was originally developed in 1889 at the famed Thomas Edison Laboratory. Film for early motion picture cameras was 1" wide and 3/4" high. In the 1950's, Hollywood found they needed to provide the public with a reason to buy movie tickets (it was easier for them to sit home and enjoy TV). Besides trying innovations like 3-D, studios experimented with the aspect ratio. "Cinemascope" was one of the early wide-screen ratios that can still be seen today. The reasoning that led to wide-screen formats is simply that the wider view is closer to the human field of vision. Because the viewer is visually drawn more into the action with wide-screen, the enjoyment level is enhanced. In the theater, wide-screen formats were easy to reproduce. They simply use more or less of the screen, as needed. However, as movies were displayed on TV screens, and later made into videos, the aspect ratio became more complicated. Initially, movies were "cropped" to fit 4:3 analog-TV sets. This is accomplished by a process called "pan and scan," which involves moving the 4:3 viewing area back and forth, to center the scene on the primary action. While pan and scan is okay if nothing is occurring in the peripheral areas, often, important information in these areas is cut off. To enable movies to be viewed in their original, wide screen aspect, the "letter box" process was developed. With "letter boxing," the picture's height is reduced, allowing the full width of the image to fit the TV screen. This enables you to see the entire scene the way it was filmed.
However, reducing the image height requires removing some information that leaves a portion of the vertical area blank. The image is displayed in the center of the screen, with the blank area divided into two, horizontal, black "bars" across the top and bottom of the screen. These bars increase or decrease, as the aspect ratio changes. However, letter-boxed movies, originally filmed in extra-wide format, can be especially troublesome when viewed on smaller TV screens, due to the extremely reduced viewing area.
Haven't seen the EPB's high-definition yet? Stop by our office, 8:00am-4:30pm weekdays and see it for yourself.
Channels currently available on the EPB's HDTV lineup include:
ESPN
HD • Discovery
HD Theater • ABC • CBS • FOX • NBC • WGN • HD Net • HDNet Movies
ESPN 2 HD • Universal HD • Outdoor Channel 2/HD • KET • TNT HD • Wealth TV • WNPT HD
HBO HD • Cinemax HD
Now available!
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much more. Take a look for answers to a lot of your questions! |
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