ATSC tuner
Such tuners are usually integrated into a television set, VCR, digital video recorder (DVR), or set-top box which provides audio/video output connectors of various types.
Some ATSC receivers, mostly those in HDTV TV sets, will stretch automatically, either by detecting black bars or by reading the Active Format Description (AFD).
[citation needed] An ATSC tuner works by generating audio and video signals that are picked up from over-the-air broadcast television.
ATSC tuners provide the following functions: selective tuning; demodulation; transport stream demultiplexing; decompression; error correction; analog-to-digital conversion; AV synchronization; and media reformatting to fit the specific type of TV screen optimally.
It is separation of a standard baseband signal from the RF carrier that was used to transmit it through the air (or down a coaxial cable or other long-distance medium.)
[citation needed] In the US, multiple digital signals are combined and then transmitted from one antenna source to create over the air broadcasts.
With error correction, the tuner has the ability to perform a number of checks and repair data so that a signal can be viewed on a TV set.
[citation needed] AV synchronization is the coordination of audio and video signals being displayed on a digital TV in proper time.
[citation needed] Media reformatting is extremely important because the formatting of images on TV sets differs significantly according to the technology employed.
[citation needed] The FCC has issued the following mandates for devices entering the US:[1][2][3] Devices manufactured before these dates can still be sold without a built-in ATSC DTV tuner; the lack of digital tuners legally must be disclosed to consumers and most name-brand retailers have incurred FCC penalties for non-compliance with these requirements.
[5] In early 2006 the US Deficit Reduction Act of 2005[6] became law, which calls for full-power over-the-air television stations to cease their analog broadcasts by February 17, 2009[7] (this cut-off date had been moved several times previously).
Canada had a similar analog TV termination date set to September 1, 2011 (except in some remote northern regions).
A Congressional bill authorized subsidized converter boxes in a way that allowed viewers to receive the new digital broadcasts on their old TVs.
[13] In Canada, the Canadian Radio-television and Telecommunications Commission (CRTC) had set August 31, 2011, as the date on which over-the-air analog TV transmission service would cease in 31 major markets of the country, including all provincial capitals, plus Ottawa (the national capital), and most other major urban centers.
Unlike in the United States, there is no plan to subsidise ATSC converter purchases and no requirement that newly imported receivers decode the digital signal.
ATSC CECB converter boxes were first carried nationally in October 2008, with chains such as Best Buy and Home Hardware offering limited selection at higher prices than in the US with no government subsidies.
[citation needed] Most ATSC tuners have relatively simple on-screen menus, and automatically bring the user to a setup screen when turned on for the first time.
If no PSIP is transmitted, the physical channel number is used, and each transport stream is enumerated according to its TSID (converted from hexadecimal), or starting sequentially at .1, .2, .3, and so forth, depending on the tuner.
