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Digital TV Basics
Now that all analog transmissions have been replaced with digital signals in the United States, many people are experiencing difficulty and frustration with understanding digital TV. The terms analog and digital can seem meaningless to the uninitiated. People often can't tell whether a television is analog or digital, or whether they're watching an analog or digital signal. When you're comparing CRT televisions to flat panel televisions and HDTVs, the situation can seem doubly confusing. However, there are many places where you can learn about digital television. When you learn the basics, you can be confident that you're buying a real digital TV.
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The Difference Between HDTV, Digital and Analog Televisions
Digital television has many improvements over analog. Since digital television signals consist of binary data, the signal can be compressed. Digital television has improved picture and sound quality over analog. Also, multiple standard definition channels, or a single high definition channel along with an electronic program guide (EPG) can be transmitted in the same bandwidth that was previously used to broadcast a single analog channel. Thus digital television has many benefits, but you can only take advantage of them if you have a digital tuner.
Most televisions sold in the United States prior to 1998 had only an analog tuner. If you want to watch digital television signals on an TV, you must connect it to a DTV converter box. Today, most new televisions that are sold have a digital tuner. This includes cathode ray tube (CRT) televisions. You don't have to buy a fancy, expensive wide-screen flat panel television to get a digital signal. The inclusion of a digital tuner is the only thing that's required to make a real digital television. So when you're shopping, check the technical specifications for the term "digital tuner" or "digital receiver" to ensure that you're really getting a digital television. In order to take advantage of high definition television (HDTV) digital signals, however, you must purchase an HDTV television. Then you must either use an antenna to pick up free-to-air HDTV signals, or pay an extra fee to your cable or satellite television provider for HD service. In many cases, a regular "rabbit ears" antenna will do. However, depending on where you live, you may need to install an outdoor television antenna to get adequate digital television signal strength.
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Types of Digital Televisions and HDTVs
The different types of digital televisions include CRT, light emitting diode (LED), liquid crystal display (LCD) and plasma televisions. CRT digital televisions are standard definition, displaying images in a 4:3 aspect ratio. LED, LCD and plasma flat panel televisions are typically HDTV capable, but can also display images in standard definition. Flat panel televisions typically display images with a 16:9 aspect ratio. Since most digital signals are transmitted in a 16:9 ratio, a flat panel digital television with the same ratio will display the entire picture. A CRT television, by comparison, will cut the picture off on the right and left so that only the center of the image is displayed.
LED digital televisions are actually LCD televisions with an LED backlight. They are usually more expensive than LCD televisions that are backlit with a fluorescent lamp. However, the picture quality of an LED television is superior to ordinary LCD, since a fluorescent backlight can't produce the deep blacks and color range that LED is capable of. LED televisions also use less electricity than ordinary flat screens, which are backlit with a cold cathode fluorescent lamp (CCFL). Plasma digital televisions are also better able to display deep blacks than LCD televisions. Plasma televisions can be viewed easily at an angle, whereas the image on an LCD television may fade when viewed from an angle. You're less likely to experience problems with blurring with a plasma television. Plasma televisions are comparable in price to LCD, but typically use more electricity during use.
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HDTV Resolutions Explained
HDTVs come in a variety of resolutions. These include 720p, 1080i and 1080p. The numbers stand for the height of the high definition television image in pixels. The "i" stands for "interlaced" and the "p" stands for "progressive scan." Progressive scan is superior to interlaced, since it provides a faster, smoother image on the screen. 1080p is considered "full HD." If you're planning to buy an HDTV, it's a good idea to invest in a 1080p model, even if you don't think you'll be able to utilize the full HD features right away.
Using these tips will help you to choose a digital television that's right for you. For more information about digital television, visit the DTV.gov website.
"LCD vs. Plasma TVs," http://www.consumerreports.org/cro/electronics-computers/tvs-services/hdtv/tv-types/lcd-vs.-plasma-3-08/overview/lcd-vs-plasma-tvs-ov.htm
"A Different Aspect," http://www.pbs.org/opb/crashcourse/aspect_ratio/
"What's an LED TV?" http://gadgetwise.blogs.nytimes.com/2009/06/11/whats-an-led-tv/
"What is DTV?" http://dtv.gov/whatisdtv.html
"What are 720p, 1080i and 1080p HDTV Resolutions?" http://tv.about.com/od/hdtv/a/whatisHDTV.htm