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Diving into digital TV
(Columbian, The (Vancouver, WA) (KRT) Via Acquire Media NewsEdge) May 12--Sometimes life on the cutting edge has its pitfalls. In 1953, the United States was one of the first countries to roll out a national standard for color television. Manufacturers then built TVs and broadcast equipment using that standard.
It took Europeans another decade to devise color TV standards. When they did, their technology was more advanced, the colors popped and the image was crisper. And the United States was stuck for decades with what many technicians believe is an inferior picture.
On Feb. 17, 2009, American TV broadcasts will be cutting-edge once more. That's the day TV stations across the country will switch off transmitters that still use the NTSC standard adopted in 1953 and rely on the new ATSC standard. The day of the digital TV transformation is upon us.
What's digital TV?
Taken literally, "analog" refers to a signal with a range of options. "Digital" is either on or off. A volume control, which allows one to gradually dial up or down the sound on the TV, gives an analog experience. The mute button -- on or off, with nothing in between -- is digital.
The old American and European standards are both based on analog signals. But digital transmissions allow broadcasters to send much more information over the airwaves using the same amount of signal space, said Don McKay, vice president of engineering at Oregon Public Broadcasting in Portland.
Portland television stations have already begun offering their digital signals, so people with digital TVs -- or digital converter boxes -- can tap the digital signal now.
Why digital?
Digital broadcasts can transmit higher-quality sound and images while using fewer airwaves. So the digital TV conversion will free up frequencies for uses such as enhanced public safety communications, according to the Federal Communications Commission.
"Las Vegas is starting a program that will use over-the-air transmissions to send information to police and fire officials during an emergency," McKay said. "Often during an emergency, the cell phone circuits are clogged. Now if a school is locked down, the school district could send floor plans to responders to give more information about what is going on, and the signal wouldn't be competing with cell phones."
Emergency communications motivated Congress to mandate the switch to digital TV, but the freed-up frequencies will also be used to offer advanced commercial wireless services, such as the high-speed Internet offering known as WiMax, according to FCC fact sheets.
More for the viewer
Digital TV signals don't just open up airwaves for new uses, they also give broadcasters power to do more, said McKay of OPB.
"In the analog realm, you can only get one channel of signal in a 6 megahertz band, which is what broadcasters are allowed," McKay said. "With digital signals, we have figured out how to get a stream of 19 megabits of digital pipeline into that bandwidth, so stations can transmit multiple stations if they wish. For instance, we only have one channel in analog, 10. In the digital realm, we have 10.1, 10.2, 10.3." Each can carry different information. (KGW-TV, for example, uses its digital signal to carry its regular channel and a locally produced weather channel.)
In fact, even with multiple channels, higher quality TV broadcasts and better sound quality, OPB has unused "digital pipeline" available in the digital realm and is exploring the possibility of someday introducing interactive TV.
"For instance, if you were watching a Scientific American program on your computer, it could pop up an icon on the right hand side of your screen," McKay said. "If you wanted more information, you could click on the icon, your picture would shrink smaller, and you could create a menu of things you could get off that. "
Some computers are already equipped for this form of over-the-air-based TV interaction, and someday soon televisions may also be able to talk to the stations.
For the low-tech
Digital TV offers lots of new options, but what if someone is happy with what they have?
Because digital TV signals are so much different from analog, most older sets can't read the new data, but that doesn't mean people have to spend hundreds of dollars on a new television.
Comcast Cable and the satellite TV companies are already automatically translating the signal for their customers and will continue to do so after Feb. 17.
Viewers who get analog TV signals through the air and who have TV sets made before March 1, 2007, may need a converter, which will cost about $60. To get a $40 coupon toward the cost, call 888-388-2009 or visit www.ntia.doc.gov/dtvcoupon.
"The quality will be the same as what you're used to," McKay said. "You'll get the signal, but it won't be digital on your TV."
Courtney Sherwood covers technology and telecommunications. Reach her at 360-735-4553 or courtney.sherwood@columbian.com.
To see more of The Columbian, or to subscribe to the newspaper, go to http://www.columbian.com.
Copyright (c) 2008, The Columbian, Vancouver, Wash.
Distributed by McClatchy-Tribune Information Services.
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