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Digital TV for beginners
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Author: Ian Tham
Topic: Technology
Viewed: 63 time(s)
[ Not Rated Yet ]
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Good news digital TV is here!
What is so great about digital TV, you wonder?
Well, for one thing resolution is much improved. Currently,
analog television provides up to 500 lines of resolution. The
resolution of an analog TV is 720 x 486 for a total of 349,920
pixels. Digital TV especially high definition television provide
resolution of up to 1920 x 1080 pixels. which gives total of
2,073,600 pixels. That means the resolution of high definition
TV is 6 times greater than analog television. Also, the pixel in
analog television resembles that of a tall building that is it
is tall and rectangular. HDTV pixels are 4 times smaller which
means you get 4 times more pixels in a given area and giving
four times more resolution. That means you get sharper and
clearer pictures.
High definition TV has a aspect ratio of 16:9 while analog TV
has an aspect ratio of 4: 3. Our field of vision is more attuned
to a wider view . We have a rectangular field of vision rather
than a square one . That means our eyes see more of the left and
right rather than the top and bottom. A wide screen image fills
more of our field of vision and provide a better picture. Films
and movies are also made closer to 16:9 ratio aspect so when
these movies are shown on TV you wouldn't get your picture cut
off or the annoying black strips on your TV set.
High definition television enables you to enjoy Dolby digital
surround sound. That means you can have 5.1 channels of sound
for your left ,center and right front speakers and two rear
surround speakers and finally a sub-woofer. Isn't that great?
Conventional analog TV uses interlaced display which show
images with 60 fields or 30 frames in a second. Each frame is
broken into two fields consisting only of even or odd rows of
240 lines. The odd rows are shown first and the scanning process
starts from left to right , then top to bottom . The whole
process is now repeated for the even rows. The process creates
artifacts such as visible scan lines and becomes more apparent
as the size of the TV screen increases. The flickering which
occurs also makes our eyes tired. Digital
TVs support progressive scanning which draws 60 full frames
in a second instead of only 60 half frames in a second. You get
a smoother image with less flicker and scan lines are hardly
noticeable.
Going digital means you have greater choices of programmes than
before. Broadcasters can choose to broadcast standard definition
television which permit multiple programming. Broadcasters are
limited bandwidth to broadcast their channels. They make use of
compression technologies called MPEG2 to remove unnecessary
parts of a picture . Take an example of a beach scene where
someone saunters across the beach. The only object that moves is
the person. So data is being transmitted only for the movement
of the person from left to right while the old data is used for
the sky, the sea and the beach.
Remember your disappointment on seeing a NSTC TV screen with
snowy images /ghostly images? This is because of broadcast
signal is being blocked or the broadcasting station is too far.
Well, you won't have this problem if you have a digital TV.
Images are either picture perfect and you don't receive it at
all. This is the nature of digital technology which is either 1
or 0.
In time to come, dig
ital television would encompass the use of interactive
television. Instead of just sitting in front of your television
being a couch potato, it offers you opportunity to shop online,
play games and enjoy other activities.
About the author:
The writer is the webmaster of digiteevee.com which
covers the use of technology in your daily life.
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