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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
win 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 Definition Television (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 51 channel surround
sound,
SDTV (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
wil!
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 TV 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 TV 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 HDTV
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 th of a second.
Broadcasters may choose to transmit different levels of resolution throughout the day,
broadcasting day programs in SDTV and night sports and movies in HDTV