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They are designed to catch your eye. Walk into any electronics store, and you¡¯ll see on the wall, the cr¨¨me de la cr¨¨me. A 54 inch, HDTV, plasma television set. It¡¯s sleek, stylish, and the best looking picture you have ever seen. You are ready to throw one, or even two, into the cart. That is, until you look at the price tag. Televisions have come a long way in just a half century. They used to be black and white. Now there¡¯s more detail, color and sharpness than ever before.
Back in the 1990¡¯s, the Federal Communications Commission mandated that all television programming be digital by the year 2006. After 2006, you'll need a "high-definition" or, HDTV, television set to watch your favorite sitcom. The television sets most people have now, will only work with a digital converter. So with the future of television right around the corner, television makers are jumping on the "HDTV revolution" with four basic kinds of sets. There are the traditional CRT picture tube sets (Cathode-Ray Tubes), LCD (liquid crystal display) sets, plasma sets, and projectors. Each have their own advantages and disadvantages.
You've seen the traditional CRT picture tube sets before. In fact, you probably have one, or two, or three in your home. This is what most people have and continues to be the most popular television today. You look through a large piece of glass. Phosphors coat the inside. The "cathode ray", which is an electrical beam, allows the phosphors to glow. That combination creates a picture. In the past, these glass fronts used to be curved. Today, the trend is to make them flat. This removes any glare so you can watch TV from just about any angle. These CRT televisions come in various sizes. You can get screens as small as 5" and as big as 36" or greater (to find out a screen size, you measure the screen diagonally). Some sets measure all the way to 40". The biggest advantage of CRT picture tube sets is the cost. These are the cheapest of the four types of sets and they should continue to be cheap for some time. You can find a small television for under $100. However, the largest sets cost a couple thousands of dollars. Most common are the 27" and the 32" sets. You can find these for $400 or $500. CRT sets also offer the best black level and provide for the best contrast. Now here is what is not so good. The PHYSICAL size. These types of televisions are big and heavy. Typically, a CRT set is 20" deep. And some can weigh over 200 pounds.
Liquid-crystal display (LCD) technology first appeared in the early 1970's. In the late 1990's, they became popular as computer monitors. Today, this technology is used for televisions. LCD sets consist of a panel of moving liquid, sandwiched in plastic. A bunch of transistors control the liquid-crystals, which controls the individual pixels on the screen. When a transistor delivers an electric charge, the crystals 'untwist' to filter light created by a lamp behind the screen. It sounds complicated, but LCD technology provides for a much better picture than CRT tubes. You'll notice the difference right away. You¡¯ll also notice these sets are much thinner, lighter and sleeker than their CRT counterparts. Where a CRT set is 20" deep, LCD sets are only a couple of inches thick. You can even hang them on the wall. The biggest problem with an LCD set is noticeable whenever you watch fast moving action. The "refresh" rate is much slower. That long pass over the middle during the big game, will look blurry because of this. For some people, this is annoying. Others don't mind as much. The viewing angle and contrast ratio are also somewhat limited. The screen size is usually limited to 30" or less, although larger sizes will appear soon. And LCD televisions cost substantially more. You can find a 17" LCD set for around $750. A 30" LCD will set you back nearly $3500.
Plasma televisions are the king of the "wow factor". Like LCD sets, plasma sets are also very thin. These sets contain chambers of plasma gas for each pixel. The plasma pixels glow with the help of a network of electrodes. Most people agree, plasma televisions offer the clearest, most brilliant picture available. Adding to their popularity, some sets range up to 63" wide. That's like having a mini-movie theater in your own house. Although today's plasma panels offer excellent picture quality, their black levels and contrast still cannot match CRTs. However, the biggest concern with plasma is "burn-in". Ever watch CNN and see the logo in the corner of the screen? If an image, such as the CNN logo, is stationary for a long time, it could stay there for an even longer period. Even when the television set is off, you could still see a "ghosting image". This is called "burn-in" and of the four different kinds of sets, the plasma set is the only one that faces this problem. If you flip through the channels, say during the commercials, you shouldn't have a problem. Another problem is the "half-life" of the set. Plasma gas will not stay at the same intensity forever. In fact, in about 7 years it will hit its "half-life". That means after 7 years, your plasma television will only be half as bright as it was when you first bought it. That¡¯s not a problem if you buy a new television every couple of years, but if you're looking to keep you set longer than that, you will start to lose some of its brightness. One last problem is for people living in the mountains. Plasma panels can produce an acoustic "buzz" when used at high altitudes. This is caused by the difference between the pressure inside the panel and the pressure outside. Usually, you only start to see problems when you reach 6,200 feet above sea level. These days, you can buy a 42" plasma set for around $3000. The larger, state of the art plasma televisions can run upwards of $15,000 or $16,000.
Projectors are becoming popular as well. These are NOT the huge movie projectors you see at the local movie theater. These small, portable projectors project an image onto a screen or a white wall. The projectors are usually mounted on the ceiling or placed on a coffee table. They work by shining a high-intensity light through a single miniature LCD panel or three individual panels for red, green and blue. The resulting light is projected through a lens onto the screen. If you are looking for a screen size of more than 61", this is what you need. You can project images as large as 25 feet. These are also nice if you don't want a huge television set cluttering up your room. It's out of the way when not in use, they are immune from "burn-in", and if the brightness starts to fade, you just have to change the light bulb. There are only three minor problems with a projector. You obviously can't stand in front of the projection. You'll cast a shadow on the picture if you do. The room also needs to be dark to get the brightest picture, especially when projecting at the biggest screen sizes. Then there is the cost. While not as expensive as some plasma sets, they can still reach $12,000. Some are on the market for $14,000. Most are in the $5000 to $7000 range.
There are some features to look for when buying your new television. At the electronics store, you are most likely to see two terms, HDTV and HD-ready. HDTV is an ¡°all in one¡± unit. These sets have an HD turner built inside the set. You can go home, plug in your TV, and immediately get HDTV. HD-ready does not have a built-in tuner. However, the lack of a built-in tuner is not necessarily a bad thing. Many of the set-top decoders provide more features than televisions with a built-in decoder. For instance, some include satellite receivers so you can get digital programming from cable stations. Also, look for component video inputs. This enables you to connect high-quality analog connection from a DVD player or satellite receiver. Then there is something called a ¡°3D comb filter.¡± To maximize the picture detail of conventional TV broadcasts, televisions need to separate the luminance (Y) from the chrominance (C). The 3D comb filter analyzes the picture over three dimensions: vertical, horizontal and time, to get the perfect picture.
Right now, more than 97% of the United States of America can receive a digital signal. In fact, your local television station is probably broadcasting in digital right now. With the future of television here right now, you now know some of the features when you go shopping for that next television set. |
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