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FREQUENTLY ASKED QUESTIONS ABOUT DIGITAL TV
Frequently
Asked Questions About Digital TV
What is digital TV (DTV)?
In April, 1997, the FCC (Federal Communications
Commission) announced that, by
2006, all television broadcasting will be digital. Digital TV broadcasting delivers
crystal-clear pictures, approaching the quality of 35mm movies and CD (compact disc)
sound. Digital broadcasts include both High Definition Television (HDTV)
and
Standard DefinitionTelevision (SDTV). Broadcasters may choose their own broadcast
formats.
HDTV (High Definition Television)
One form of digital broadcasting is HDTV, which provides the highest resolution
picture. Besides incredible picture, the sound is available in the 5.1 channel surround
sound.
SOTV (Standard Definition Television)
Another form of digital broadcasting is SDTV, which provides lower resolution, but still
presents a very sharp, clear picture. Lower resolution allows broadcasters to transmit
more than one program per channel.
When will TV stations
start broadcasting
digital signals?
Television stations are required to continue broadcasting regular TV signals along side
the digital signals until 2006. Cable TV and satellite "IV are not affected by this FCC
ruling.
All stations are required to become digital by 2006. This will be an evolutionary
process. According to the FCC, digital broadcasting must be available in the top ten
markets, covering 30% of households by May 1999.
By the end of 1999, digital
broadcasting must be available in the top 30 markets, covering 50% of households.
Will I be able to adapt my current TV to receive digital broadcasts?
Manufacturers will offer a digital IV set-top box (DTV-STB) which will allow current
televisions to display digitally broadcast programs. The picture and sound quality will
be about the same as small dish digital satellite systems today.
Conventional televisions (non-digital televisions) will not be able to display the HDIV
resolution quality or sound.
What digital formats will broadcasters
use?
There are presently four DTV formats: 1080i (interlaced), 720p (progressive), 480i and
480p. The higher numbers indicate a higher resolution picture.
In an interlaced picture, the odd numbered lines (picture information) are scanned first
creating field 1 and then the even numbered lines are scanned, creating field 2. The
two fields are then interlaced to provide the entire image (one frame).
This process
happens in 1/30th of a second and is invisible to the human eye.
In progressive
scanning, all lines in the entire frame are scanned sequentially in 1/60 thof a second.
Broadcasters may choose to transmit different levels of resolution throughout the day,
broadcasting day programs in SD'rV and night sports and movies in HD'I-V.
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