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High Definition TV (HDTV) Fundamentals


HDTv Set DIGITAL TELEVISION
Most, but not all (see below), television's manufactured since March 2007 have a built-in digital tuner, or more specifically an ATSC tuner, for receiving over-the-air TV.

INDUSTRY STANDARDS
Digital TV - ATSC (Advanced Television System Committee)
Analog TV - NTSC (National Television System Committee)

The ATSC Digital TV Standards include;

See the ATSC Website for a list of downloadable specifications.

Some televisions with digital tuners do not use a low noise receiver (common in analog TV's), and may not get some weaker signals. One reason not to use a low noise receiver is to cut cost, another is satellite and cable TV does not (usually) require a low noise receiver.

Virtually all televisions can be used as a video monitor. Many can also process both digital and analog signals (ATSC and NTSC), allowing the TV to work with analog DVD players, VCR's, and older video games.

TV MONITORS
A few digital TV's can only receive signals from a cable or satellite TV box, or camera, video game, computer. These TV's are video monitors only and cannot receive over-the-air signals.

Common Television Labels
    Gets OTA DTv
  • Digital Tuner
    • ATSC
    • HDTV
    • EDTV
    • SDTV
    • HiDef
    Doesn't get OTA DTv
  • Analog Tuner
    • NTSC
  • Video Monitor
    • HD-Ready
    • Digital-Ready
    • Digital Monitor
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STANDARD & HIGH DEFINITION
Over-the-air digital television can broadcast sub channels in High Definition (HDTV), or Standard Definition (SDTV) resolution. There are 3 basic types of displays for HDTV, and 2 types for SDTV.

HDTV
720p
1080i
1080p
SDTV
480p
480i
The number is height resolution in pixels per inch.
"p" stands for Progressive - picture lines displayed one after the other.
"i" stands for Interlaced - odd picture lines displayed then even lines.

High definition display's can use aspect ratios (width:height) of 16:9 or 1:1, standard definition can additionally use 4:3.

Aspect Ratio
16:9
Wide Screen
HDTV, SDTV
4:3
Analog TV ratio
SDTV
1:1
Square
HDTV, SDTV

The frame rates in North America are 23.976, 24, 29.97, 30, 59.94, and 60 frames per second (fps). The old analog system used 30 fps, most Hollywood movies run at 24 fps.

Broadcast DTv Display Types
ATSC Document A/53 Part 4:2009
Definition Resolution
H x W (PPI)
Aspect
Ratio
Frame
Rate
High
Definition
(HDTV)
1080p 1080 x 1920 16:9
1:1
24 fps(1)
30 fps(2)
1080i 30 fps(2)
720p 720 x 1280 24 fps(1)
30 fps(2)
60 fps(3)
Standard
Definition
(SDTV)
480p 480 x 704 16:9
4:3
24 fps(1)
30 fps(2)
60 fps(3)
480 x 640 4:3
1:1
480i 480 x 704 16:9
4:3
30 fps(2)
480 x 640 4:3
1:1
Frame Rate
(1)
(2)
(3)
24
30
60
or
or
or
23.976
29.97
59.94
fps
fps
fps

H = height, W = width, PPI = pixels per inch.

The old analog TV system displayed an interlaced (i) picture, had an aspect ratio of 4:3, a frame rate of 30 fps, and only had mono audio.

Ultra High Definition (UHD) / 4k resolution (next-Gen TV)
Stations will continue to broadcast using the current standard (ATSC 1.0), but will have the option to simulcast on another frequency an Ultra High Definition signal (ATSC 3.0). The UHD signal will have higher resolution (3840 x 2160), great for extremely large screens, but of little value to small and moderate size screens. UHD will also have high dynamic range which changes colors faster for a better picture, and a maximum frame rate of 120 fps.. Additionally, UHD will have better reception by using new techniques that allow for a lower signal-to-noise ratio. UHD may catch on, or may go by the way of quadrophonic FM radio.

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High Definition TV (HDTV) Fundamentals
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