In March 1990, when it became clear that a digital standard was possible, the FCC made several

critical decisions. First, the Commission declared that the new ATV standard must be more than
an enhanced analog signal but be able to provide a genuine HDTV signal with at least twice the
resolution of existing television images. (7) Then, to ensure that viewers who did not wish to buy
a new digital television set could continue to receive conventional television broadcasts, it
dictated that the new ATV standard must be capable of being "simulcast" on different channels.
(8) The new ATV standard also allowed the new DTV signal to be based on entirely new design
principles. Although incompatible with the existing NTSC standard, the new DTV standard
would be able to incorporate many improvements.

The last standards adopted by the FCC did not require a single standard for scanning formats,
aspect ratios, or lines of resolution. This compromise resulted from a dispute between the
consumer electronics industry (joined by some broadcasters) and the computer industry (joined
by the film industry and some public interest groups) over which of the two scanning processes—
interlaced or progressive—would be best suited for the newer digital HDTV compatible display
devices.[147] Interlaced scanning, which had been specifically designed for older analog CRT
display technologies, scans even-numbered lines first, then odd-numbered ones. Interlaced
scanning can be regarded as the first video compression model. It was partly developed in the
1940s to double the image resolution to exceed the limitations of television broadcast bandwidth.
Another reason for its adoption was to limit the flickering on early CRT screens, whose
phosphor-coated screens could only retain the image from the electron scanning gun for a
relatively short duration.[148] However, interlaced scanning does not work as efficiently on
newer display devices such as Liquid-crystal (LCD), for example, which are better suited to a
more frequent progressive refresh rate.[147]

Progressive scanning, the format that the computer industry had long adopted for computer
display monitors, scans every line in sequence, from top to bottom. Progressive scanning, in
effect, doubles the amount of data generated for every full screen displayed in comparison to
interlaced scanning by painting the screen in one pass in 1/60-second instead of two passes in
1/30-second. The computer industry argued that progressive scanning is superior because it does
not "flicker" on the new standard of display devices in the manner of interlaced scanning. It also
argued that progressive scanning enables easier connections with the Internet and is more cheaply
converted to interlaced formats than vice versa. The film industry also supported progressive
scanning because it offered a more efficient means of converting filmed programming into digital
formats. For their part, the consumer electronics industry and broadcasters argued that interlaced
scanning was the only technology that could transmit the highest quality pictures then (and
currently) feasible, i.e., 1,080 lines per picture and 1,920 pixels per line. Broadcasters also
favored interlaced scanning because their vast archive of interlaced programming is not readily
compatible with a progressive format. William F. Schreiber, who was director of the Advanced
Television Research Program at the Massachusetts Institute of Technology from 1983 until his
retirement in 1990, thought that the continued advocacy of interlaced equipment originated from
consumer electronics companies that were trying to get back the substantial investments they
made in the interlaced technology.[149]

Digital television transition started in late 2000s. All governments across the world set the
deadline for analog shutdown by the 2010s. Initially, the adoption rate was low, as the first digital
tuner-equipped television sets were costly. However, as the price of digital-capable television sets
dropped, more and more households started converting to digital television sets. The transition is
expected to be completed worldwide by the mid to late 2010s.

Smart television
Main article: Smart television
Not to be confused with Internet television, Internet Protocol television, or Web television.

A smart TV
The advent of digital television allowed innovations like smart television sets. A smart television
sometimes referred to as a "connected TV" or "hybrid TV," is a television set or set-top box with
integrated Internet and Web 2.0 features and is an example of technological convergence between
computers, television sets, and set-top boxes. Besides the traditional functions of television sets
and set-top boxes provided through traditional Broadcasting media, these devices can also
provide Internet TV, online interactive media, over-the-top content, as well as on-demand
streaming media, and home networking access. These TVs come pre-loaded with an operating
system.[10][150][151][152]

Smart TV is not to be confused with Internet TV, Internet Protocol television (IPTV), or with
Web TV. Internet television refers to receiving television content over the Internet instead of
through traditional systems—terrestrial, cable, and satellite. IPTV is one of the emerging Internet
television technology standards for television networks. Web television (WebTV) is a term used
for programs created by a wide variety of companies and individuals for broadcast on Internet
TV. A first patent was filed in 1994[153] (and extended the following year)[154] for an
"intelligent" television system, linked with data processing systems, using a digital or analog
network. Apart from being linked to data networks, one key point is its ability to automatically
download necessary software routines according to a user's demand and process their needs.
Major TV manufacturers announced the production of smart TVs only for middle-end and high-
end TVs in 2015.[7][8][9] Smart TVs have gotten more affordable compared to when they were
first introduced, with 46 million U.S. households having at least one as of 2019.[155]

3D
Main article: 3D television
3D television conveys depth perception to the viewer by employing techniques such as
stereoscopic display, multi-view display, 2D-plus-depth, or any other form of 3D display. Most
modern 3D television sets use an active shutter 3D system or a polarized 3D system, and some
are autostereoscopic without the need for glasses. Stereoscopic 3D television was demonstrated
for the first time on 10 August 1928, by John Logie Baird in his company's premises at 133 Long
Acre, London.[156] Baird pioneered a variety of 3D television systems using electromechanical
and cathode-ray tube techniques. The first 3D television was produced in 1935. The advent of
digital television in the 2000s greatly improved 3D television sets. Although 3D television sets
are quite popular for watching 3D home media, such as on Blu-ray discs, 3D programming has
largely failed to make inroads with the public. As a result, many 3D television channels that
started in the early 2010s were shut down by the mid-2010s. According to DisplaySearch 3D
television shipments totaled 41.45 million units in 2012, compared with 24.14 in 2011 and 2.26
in 2010.[157] As of late 2013, the number of 3D TV viewers started to
decline.[158][159][160][161][162]

Broadcast systems
Terrestrial television
Main article: Terrestrial television
See also: Timeline of the introduction of television in countries

A modern high gain UHF Yagi television antenna. It has 17 directors and one reflector (made of
4 rods) shaped as a corner reflector.
Programming is broadcast by television stations, sometimes called "channels," as stations are
licensed by their governments to broadcast only over assigned channels in the television band. At
first, terrestrial broadcasting was the only way television could be widely distributed, and because
bandwidth was limited, i.e., there were only a small number of channels available, government
regulation was the norm. In the U.S., the Federal Communications Commission (FCC) allowed
stations to broadcast advertisements beginning in July 1941 but required public service
programming commitments as a requirement for a license. By contrast, the United Kingdom
chose a different route, imposing a television license fee on owners of television reception
equipment to fund the British Broadcasting Corporation (BBC), which had public service as part
of its Royal Charter.

WRGB claims to be the world's oldest television station, tracing its roots to an experimental
station founded on 13 January 1928, broadcasting from the General Electric factory in
Schenectady, NY, under the call letters W2XB.[163] It was popularly known as "WGY
Television" after its sister radio station. Later, in 1928, General Electric started a second facility,
this one in New York City, which had the call letters W2XBS and which today is known as
WNBC. The two stations were experimental and had no regular programming, as receivers were
operated by engineers within the company. The image of a Felix the Cat doll rotating on a
turntable was broadcast for 2 hours every day for several years as engineers tested new
technology. On 2 November 1936, the BBC began transmitting the world's first public regular
high-definition service from the Victorian Alexandra Palace in north London.[164] It therefore
claims to be the birthplace of television broadcasting as we now know it.

With the widespread adoption of cable across the United States in the 1970s and 1980s, terrestrial
television broadcasts have been in decline; in 2013 it was estimated that about 7% of US
households used an antenna.[165][166] A slight increase in use began around 2010 due to
switchover to digital terrestrial television broadcasts, which offered pristine image quality over
very large areas, and offered an alternative to cable television (CATV) for cord cutters. All other
countries around the world are also in the process of either shutting down analog terrestrial
television or switching over to digital terrestrial television.

Cable television
Main article: Cable television
See also: Cable television by region

Coaxial cable is used to carry cable television signals into cathode-ray tube and flat-panel
television sets.
Cable television is a system of broadcasting television programming to paying subscribers via
radio frequency (RF) signals transmitted through coaxial cables or light pulses through fiber-
optic cables. This contrasts with traditional terrestrial television, in which the television signal is
transmitted over the air by radio waves and received by a television antenna attached to the
television. In the 2000s, FM radio programming, high-speed Internet, telephone service, and
similar non-television services may also be provided through these cables. The abbreviation
CATV is sometimes used for cable television in the United States. It originally stood for
Community Access Television or Community Antenna Television, from cable television's origins
in 1948: in areas where over-the-air reception was limited by distance from transmitters or
mountainous terrain, large "community antennas" were constructed, and cable was run from them
to individual homes.[167]

Satellite television
Main article: Satellite television

DBS satellite dishes installed on an apartment complex

Satellite television is a system of supplying television programming using broadcast signals
relayed from communication satellites. The signals are received via an outdoor parabolic reflector
antenna, usually referred to as a satellite dish and a low-noise block downconverter (LNB). A
satellite receiver then decodes the desired television program for viewing on a television set.
Receivers can be external set-top boxes, or a built-in television tuner. Satellite television provides
a wide range of channels and services, especially to geographic areas without terrestrial television
or cable television.

The most common method of reception is direct-broadcast satellite television (DBSTV), also
known as "direct to home" (DTH).[168] In DBSTV systems, signals are relayed from a direct
broadcast satellite on the Ku wavelength and are completely digital.[169] Satellite TV systems
formerly used systems known as television receive-only. These systems received analog signals
transmitted in the C-band spectrum from FSS type satellites and required the use of large dishes.
Consequently, these systems were nicknamed "big dish" systems and were more expensive and
less popular.[170]

The direct-broadcast satellite television signals were earlier analog signals and later digital
signals, both of which require a compatible receiver. Digital signals may include high-definition
television (HDTV). Some transmissions and channels are free-to-air or