ATSC tuner

An ATSC (Advanced Television Systems Committee) tuner, often called an ATSC receiver or HDTV tuner is a type of television tuner that allows reception of digital television (DTV) television channels transmitted by television stations in North America, parts of Central America and South Korea that use ATSC standards. Such tuners may be integrated into a television set, VCR, digital video recorder (DVR), or set-top box that provides audio/video output connectors of various types.

Another type of television tuner is a digital television adapter (DTA) with an analog passthrough.

Technical overview

The terms "tuner" and "receiver" are used loosely, and it is perhaps more appropriately called an ATSC receiver, with the tuner being part of the receiver (see Metonymy). The receiver generates the audio and video (AV) signals needed for television, and performs the following tasks: demodulation, error correction, MPEG transport stream demultiplexing, decompression, AV synchronization, and media reformatting to match what is optimal input for one's TV. Examples of media reformatting include: interlace to progressive scan or vice versa, picture resolutions, aspect ratio conversions (16:9 to or from 4:3), frame rate conversion, even image scaling. Zooming is an example of resolution change. It is commonly used to convert a low-resolution picture to a high-resolution display. This lets the user eliminate letterboxing or pillarboxing by stretching or cropping the picture. Some ATSC receivers, mostly those in HDTV TV sets, will stretch automatically, either by detecting black bars, or reading the Active Format Descriptor (AFD).

ATSC standards

Advanced Television Systems Committee (ATSC) standards are a set of standards developed by the Advanced Television Systems Committee for digital television transmission over terrestrial, cable, and satellite networks.

The ATSC standards were developed in the early 1990s by the Grand Alliance, a consortium of electronics and telecommunications companies that assembled to develop a specification for what is now known as HDTV. ATSC formats also include standard-definition formats, although initially only HDTV services were launched in the digital format.

Background

The high definition television standards defined by the ATSC produce wide screen 16:9 images up to 1920×1080 pixels in size – more than six times the display resolution of the earlier standard. However, many different image sizes are also supported. The reduced bandwidth requirements of lower-resolution images allow up to six standard-definition "subchannels" to be broadcast on a single 6 MHz TV channel.

ATSC standards are marked A/x (x is the standard number) and can be downloaded for free from the ATSC's website at ATSC.org. ATSC Standard A/53, which implemented the system developed by the Grand Alliance, was published in 1995; the standard was adopted by the Federal Communications Commission in the United States in 1996. It was revised in 2009. ATSC Standard A/72 was approved in 2008 and introduces H.264/AVC video coding to the ATSC system.

High-definition television

High-definition television (HDTV) provides a resolution that is substantially higher than that of standard-definition television.

HDTV may be transmitted in various formats:

The letter "p" here stands for progressive scan, while "i" indicates interlaced.

When transmitted at two megapixels per frame, HDTV provides about five times as many pixels as SD (standard-definition television).

History

The term high definition once described a series of television systems originating from August 1936; however, these systems were only high definition when compared to earlier systems that were based on mechanical systems with as few as 30 lines of resolution. The ongoing competition between companies and nations to create true "HDTV" spanned the entire 20th century, as each new system became more HD than the last. Ironically, in the beginning of the 21st century, this race has continued with 4k, 5k and current 8K systems.

Digital television

Digital television (DTV) is the transmission of audio and video by digitally processed and multiplexed signal, in contrast to the totally analog and channel separated signals used by analog television. Digital TV can support more than one program in the same channel bandwidth. It is an innovative service that represents the first significant evolution in television technology since color television in the 1950s. Several regions of the world are in different stages of adaptation and are implementing different broadcasting standards. Below are the different widely used digital television broadcasting standards (DTB):

Media player

A media player could refer to: