FAQ’S: HDTV
What is Digital
Television or DTV?
Digital TVs are televisions that can receive and
display digital television broadcasts sent using any one of eighteen digital
signaling methods. Consumer Electronics Association (CEA) classifies digital
televisions in three broad categories: HDTV (High Definition TV), EDTV
(Enhanced Digital TV), and SDTV (Standard Definition TV).
How is my current
television different from DTVs?
The TV you watch today is based on an analog system
developed over 50 years ago. Due to the analog nature of the system, it is
likely that your current TV was designed to receive analog signals only. You
can receive and display digital broadcasts on your existing analog TV through a
digital-to-analog converter box; however, its quality is compromised by the
display limitations of the analog TV.
What is the difference
between HDTV, EDTV, and SDTV?
HDTV, EDTV, and
SDTV reference the ability of a digital television to re-display various
digital TV broadcasts in its original format. Digital TV broadcasts can be
transmitted using any one of eighteen resolution-formats (See#4); however,
digital televisions differ in their ability to redisplay the image, especially
when a high-definition image is received.
HDTVs can receive all 18 formats and re-display high-definition images using
540 lines (1080 lines interlaced) or 720 lines (progressive scanning method)
without down converting.
EDTVs can receive all 18 formats including high-definition broadcasts and all
18 formats are re-displayed at 480 lines using progressive scan method. This
method reduces flicker; however, picture quality may not necessarily outperform
480 interlaced when viewed at normal viewing distances.
SDTVs can receive all 18 formats including high-definition broadcasts and all
18 formats are re-displayed at 480 lines using interlacing (same resolution as
current analog TVs). This means that high-definition broadcasts are
down-converted in order to display the image at 480 lines.
What are the 18
formats of ATSC standard?
There are 18 digital television formats prescribed
by the Advanced Televisions Systems Committee. Six are considered HDTV formats
(1080p, 1080i, and 720p). Each format has a different combination of screen
resolution, scan mode, frame rate, and aspect ratio requirements.
ATSC Picture Display Format
|
|
Format |
Vertical Scan Lines |
Horizontal Pixels |
Aspect Ratio |
Scan Mode |
Frame Rate (fps) |
|
|
1080p |
1080 |
1920 |
16:9 |
Progressive |
24 |
|
1080p |
1080 |
1920 |
16:9 |
Progressive |
30 |
|
|
1080i |
1080 |
1920 |
16:9 |
Interlaced |
30 |
|
|
720p |
720 |
1280 |
16:9 |
Progressive |
24 |
|
|
720p |
720 |
1280 |
16:9 |
Progressive |
30 |
|
|
720p |
720 |
1280 |
16:9 |
Progressive |
60 |
|
|
|
480p |
480 |
704 |
16:9 |
Progressive |
24 |
|
480p |
480 |
704 |
16:9 |
Progressive |
30 |
|
|
480p |
480 |
704 |
16:9 |
Progressive |
60 |
|
|
480p |
480 |
704 |
4:3 |
Progressive |
24 |
|
|
480p |
480 |
704 |
4:3 |
Progressive |
30 |
|
|
480p |
480 |
704 |
4:3 |
Progressive |
60 |
|
|
480p |
480 |
640 |
4:3 |
Progressive |
24 |
|
|
480p |
480 |
640 |
4:3 |
Progressive |
30 |
|
|
480p |
480 |
640 |
4:3 |
Progressive |
60 |
|
|
|
480i |
480 |
704 |
16:9 |
Interlaced |
30 |
|
480i |
480 |
704 |
4:3 |
Interlaced |
30 |
|
|
480i |
480 |
640 |
4:3 |
Interlaced |
30 |
Vertical Scan
Lines
Vertical scan lines refer to the number of horizontal lines a television can
display to create an image. As the number of lines increase, more information
is displayed, resulting in better picture quality. Traditional analog TVs can
display approximately 480 lines, while high-definition television can display
up to 1080 lines.
Horizontal
Pixels
Each horizontal line in a TV is made up of individual dots (pixels). The higher
the number of pixels, the finer the TV picture becomes. Horizontal pixel
measurements using today's technology can range from 250 for a VCR to as much
as 500 for a DVD player. Typical digital TV broadcasts have at least 640
pixels.
Aspect
Ratio
Aspect ratio identifies the ratio of the TV screen's width over its height. A
16:9 aspect ratio refers to a wide-screen picture format, while a 4:3 refers to
a standard TV format.
Scan Mode
Interlaced scanning is a method that creates a TV picture with alternating
lines of information and is the cause for flickering. Progressive scanning is a
method that creates a TV picture with consecutive lines of information that
results in flicker-free picture quality.
Frame Rate
Motion picture on your TV is generated by a series of still pictures that
changes from picture to picture at a very fast rate. This rate is measured by
the number of still pictures (frames) displayed within one second of time. The
higher the frame-rate, the smoother the picture displayed.
|
|
What are the different
display technologies used in Digital Televisions?
Digital televisions use the same display technologies available today for
analog TVs and computer monitors. They include CRT (Cathode Ray Tubes), LCD
(Liquid Crystal Displays), front and rear projection, and PDP (Plasma Display
Panels). Most digital TVs today use CRT and projection technologies; however,
the CRT maintains an advantage over projection technologies with a wider
viewing angle that makes it more suitable for living room viewing.
How is a
HDTV/EDTV/SDTV different from a HDTV/EDTV/SDTV Monitor?
In order to receive digital broadcasts, a digital decoder must be used to
receive and decode digital broadcast signals. Digital decoders can be built
into the digital television itself or they may come in the form of a set-top
box that is added separately to the television. HDTV/EDTV/SDTV Monitors are
digital televisions without a digital decoder built into the television.
HDTV/EDTV/SDTV Monitors give you the flexibility to add a digital decoder in
the future when digital broadcasts are more prevalent.
What are the benefits
of a Digital Television?
The primary benefits of digital televisions are superior picture quality and
better sound. The analog TV signals we watch today are made of 525 interlaced
lines and are subject to screen flickering, ghost-shadows, and blurring.
Digital televisions are dramatically different in that they receive signals
digitally in the form of 0s and 1s so problems with ghost-shadows and blurring
go away. Digital signals also produce a higher quality TV picture, displaying
crisp, sharp and vivid images using up to 1080 lines instead of 525 lines.
Additionally, digital television signals can deliver cinema-quality sound
effects using 6-channel Dolby Digital surround sound instead of only two
regular stereo channels.
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|
Are digital broadcasts
available now?
Digital broadcasts are available through terrestrial (antenna), satellite, and
in the near future, cable systems. Major television networks such as ABC, NBC,
CBS, Fox, and HBO have already begun broadcasting digital TV programming.
Do I need component
inputs or RGB inputs for my DTV?
RGB inputs and component inputs are the best
connectivity interface for use with todays high-resolution digital sources such
as DVD players (standard or progressive) and HDTV decoder set-top boxes. RGB
and component inputs work with video signals that are split into its base
components, resulting in a cleaner and purer video signal than all other
connection options. There are two types of component inputs and Sampo HDTV
Monitors/TVs are equipped with both. The standard component inputs can accept
480i signals while the high-definition component inputs can handle 480i, 480p,
720p, and 1080i signals from progressive DVD players and HDTV decoder set-top
boxes.
Can I connect a DTV to
my PC or Laptop?
Yes, as long as the digital television is equipped with an RGB input (15-pin
D-sub connector). A digital television is essentially a high quality computer
monitor capable of displaying various resolutions from today's advanced video
cards. All Sampo HDTV Monitors/TVs are equipped with an RGB-output that lets
you connect multiple monitors in series for multimedia presentation purposes.
What does
"down-convert" mean?
Down-convert takes place when a digital broadcast signal exceeds the display
capabilities of the digital television and the broadcast signal is reduced to
match the television's limited display capabilities. For example, if NBC
broadcasts a digital program using 1080 lines (1080i format) while the digital
television is only able to display 480 lines (480i or 480p), the 1080i signal
is reduced or down-converted to only 480 lines, resulting in inferior picture
quality. Sampo HDTV Monitors/TVs can display all digital resolutions from 480
lines to high-definition 1080 lines, eliminating the need for the HDTV decoder
to down-convert broadcast signals.
What does
"up-convert" mean?
Up-convert takes place when a digital television's display capabilities exceed
the digital broadcast signal and the broadcast signal is increased to match the
TV's display program using 480 lines (480i or 480p) and the digital television
is able to display 1080 lines, the signal is increased or up-converted to match
the TV, resulting in hazy picture quality. Sampo HDTV Monitors/TVs can display
all digital resolutions from 480 lines to high-definition 1080 lines,
eliminating the need for the HDTV decoder to up-convert broadcast signals.
Are digital
televisions compatible with my existing video equipment?
Most digital televisions are compatible with your existing video equipment; however,
this depends on the types of connectivity options available on the digital TV.
All Sampo HDTV Monitors/TVs are equipped with multiple connection options for
connections with your existing video equipment including VCRs, DVD players,
Progressive DVD players, LaserDisc/VideoCD Players, analog and digital
camcorders, Digital VHS players, and video game machines.
What will the future
of digital television look like?
The broad bandwidth of the new digital television system facilitates a whole
new spectrum of programming and data services for your home. For example, this
bandwidth allows at least 4 standard-definition TV broadcasts to simultaneously
display on your digital TV screen, in addition to displaying data content such
as news, stock reports, email, and other data related services. In the near
future, your digital television will become an information resource hosting
multiple broadcasts in multiple windows while displaying data content in banner
strips.
Note: All
information provided by Sampo.