NTSC vs ATSC

There are three main television standards used throughout the world:

1. NTSC - National Television Standards Committee

2. SECAM - Système Électronique pour Couleur avec Mèmoire. 

3. PAL - Phase Alternating Line

Television Standards

What is NTSC?

NTSC (National Television Systems Committee) is the standard for

analog television transmission in the United States and many other

counties worldwide.

Developed in 1953 by the National Television System Committee.

Alternatives to NTSC were developed later, including PAL and

SECAM.

NTSC provides 482 lines of vertical resolution and 16 million colors.

NTSC transmits 525 lines, but some lines are used for sync, vertical

retrace, and closed captioning.

What is NTSC?

NTSC delivers 29.97 frames per second & it does this by delivering

59.94 interlaced half-frames per second.

Interlacing is a technique of alternating the transmission of even

lines and odd lines to raise the effective resolution without

increasing bandwidth utilization.

NTSC has an aspect ratio of 4:3.

USA, Antigua, Bahamas, Barbados, Belize, Bermuda, Bolivia, Burma, Canada, Chile,

Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, El Salvador, Greenland, Guam,

Guatemala, Guyana, Honduras, Jamaica, Japan, South Korea, Mexico, Netherlands Antilles,

Nicaragua, Panama, Peru, Philippines, Puerto Rico, St. Vincent & the Grenadines, St. Kitts,

Saipan, Samoa, Surinam, Taiwan, Tobago, Trinidad, Venezuela, Virgin Islands etc.

Countries using NTSC

 NTSC is an analog system. In computer video, colors and brightness

are represented by numbers. But with analog television, everything is

just voltages, and voltages are affected by wire length, connectors, heat,

cold, video tape, and on and on.

There is an inherent colour problem in the NTSC system for television

where the same colours can change hue from one side of the screen to

the other due to multi-path distortions (reflection of the signals off objects

before they reach the antennae) of the broadcast signals and because

the frequency is only recalibrated at the start of each line on the screen.

Disadvantages of NTSC

ATSC (Advanced Television Systems Committee)

The ATSC standard was developed in the early 90’s

ATSC is the digital replacement for the earlier analog standard, NTSC.

It produces wide screen 16:9, images up to 1920×1080 pixels in size; more than six times the display resolution of the earlier standard i.e. NTSC

ATSC increases "theater quality" audio because it uses the Dolby Digital format to provide "5.1" surround sound.

ATSC is also used in Canada, South Korea, Argentina, and Mexico.

The change is very much like the jump from VHS to CD in home theater systems.

The ATSC standards include high definition television (HDTV), standard definition television (SDTV), data broadcasting, multi-channel surround- sound audio, and satellite direct-to-home broadcasting.

•SDTV and HDTV, ATSC chose MPEG-2 for video and Dolby Digital for audio.

•720 – 1080 line formats are considered HDTV

•Scans at 480 lines are SDTV

The Standards

MPEG-2

reduces a digital signal from 166 Mbits to 5 Mbits

MPEG-2 uses the lossy compression method

Used for video compression and transport.

Dolby Digital

reduces the amount of data needed to produce high quality sound.

Dolby Digital is used with digital versatile disks (DVD), DTV, and digital cable and satellite transmissions.

Dolby Digital provides five full bandwidth channels: front left, front right, center, surround left, and surround right, for true surround sound quality.So it has better sound quality

The ATSC decided to use Dolby Digital as a standard for DTV because of its popularity with film producers and consumers, its ability to use a single audio stream because of the downmixing feature, and its high-quality sound.

The Display Formats

There are 18 officially sanctioned standards for DTV display, all of which fall into one of these two categories: digital television sets are either HDTV-capable, or SDTV-capable. The sets can receive both types of broadcasts, but will convert signals received to their own resolution capabilities.

One important feature of the ATSC standards is the support of two scanning methods for the television screen:

interlacing and progressive scanning

Interlacing takes two screen scans to complete a frame: one scan for the odd-numbered horizontal lines, and another scan for the even-numbered lines. Interlacing is important to some broadcasters.

Progressive scanning, also called non-interlaced scanning, scans the lines sequentially. Progressive scanning is computer friendly.

HDTV

HDTV (high definition television) is the high-end television display technology that provides picture quality similar to 35 mm.

Some television stations have begun transmitting HDTV broadcasts to users on a limited number of channels.

HDTV generally uses digital rather than analog signal transmission.

HDTV offers a vertical resolution display from 720p to 1080i and higher.

The p stands for progressive scanning , which means that each scan includes every line for a complete picture, and the i stands for interlaced scanning which means that each scan includes alternate lines for half a picture.

One of HDTV's most prominent features is its wider aspect ratio of 16:9.

SDTV

SDTV is a DTV format that provides a picture quality similar to DVD.

SDTV has a range resolutions below those of HDTV and no defined aspect ratio.

They broadcast SDTV programs in the daytime and to broadcast HDTV programs during prime time broadcasting.

The picture, even when displayed on a small TV, is better quality.

A digital signal can support a higher resolution, so the picture will still look good when shown on a larger TV screen.

The video can be progressive rather than interlaced -- the screen shows the entire picture for every frame instead of every other line of pixels.

TV stations can broadcast several signals using the same bandwidth. This is called multicasting.

If broadcasters choose to, they can include interactive content or additional information with the DTV signal.

It can support high-definition (HDTV) broadcasts.

Advantages

1. NTSC is a set of standards for analog TV transmission while ATSC is a set of standards for digital TV transmission.

2. ATSC allows HDTV quality while NTSC does not.

3. ATSC uses the wide screen format while NTSC follows the 4:3 ratio.

4. ATSC requires much lesser bandwidth compared to NTSC.

5. ATSC is able to transmit 5.1 surround sound while NTSC is not, it is only able to carry 2 channels of sound leading to stereo quality sound.

6. ATSC is gradually replacing NTSC.

NTSC vs ATSC