Editing Broadcasting (section)

== History ==
{{Main|History of broadcasting}}
In 1894, Italian inventor [[Guglielmo Marconi]] began developing a wireless communication using the then-newly discovered phenomenon of [[radio wave]]s, showing by 1901 that they could be transmitted across the Atlantic Ocean.<ref>{{cite web |last=Vujovic |first=Ljubo |year=1998 |title=Tesla Biography |url=http://www.teslasociety.com/biography.htm |archive-url=https://web.archive.org/web/20160114205727/http://www.teslasociety.com/biography.htm |archive-date=14 January 2016 |publisher=Tesla Memorial Society of New York}}</ref> This was the start of [[wireless telegraphy]] by radio. Audio radio broadcasting began experimentally in the first decade of the 20th century. On 17 December 1902, a transmission from the Marconi station in [[Glace Bay]], Nova Scotia, Canada, became the world's first radio message to cross the Atlantic from North America. In 1904, a commercial service was established to transmit nightly news summaries to subscribing ships, which incorporated them into their onboard newspapers.<ref>{{Cite web |title=TR Center – Talking Across the Ocean |url=https://www.theodorerooseveltcenter.org/Blog/Item/Talking%20Across%20the%20Ocean |access-date=12 March 2021 |publisher=theodorerooseveltcenter.org |archive-date=17 April 2021 |archive-url=https://web.archive.org/web/20210417162827/https://www.theodorerooseveltcenter.org/Blog/Item/Talking%20Across%20the%20Ocean |url-status=live }}</ref>

[[World War I]] accelerated the development of radio for [[military communications]]. After the war, commercial radio [[AM broadcasting]] began in the 1920s and became an important mass medium for entertainment and news. [[World War II]] again accelerated the development of radio for the wartime purposes of aircraft and land communication, radio navigation, and radar.<ref>{{cite book | last=Thompson | first=R.J. Jr. |title=Crystal Clear: The Struggle for Reliable Communications Technology in World War II |publisher=Wiley |year=2011 |isbn=9781118104644 }}</ref> Development of stereo [[FM broadcasting]] of radio began in the 1930s in the United States and the 1970s in the United Kingdom, displacing AM as the dominant commercial standard.<ref>{{cite book |last1=Théberge |first1=P. |title=Living Stereo: Histories and Cultures of Multichannel Sound |last2=Devine |first2=K. |last3=Everrett |first3=T |publisher=Bloomsbury Publishing |year=2015 |isbn=9781623566654 }}</ref>

On 25 March 1925, [[John Logie Baird]] demonstrated the transmission of moving pictures at the London department store [[Selfridges]]. Baird's device relied upon the [[Nipkow disk]] and thus became known as the [[mechanical television]]. It formed the basis of experimental broadcasts done by the [[British Broadcasting Corporation]] beginning on 30 September 1929.<ref>{{cite web |year=2006 |title=The Pioneers |url=http://www.mztv.com/newframe.asp?content=http://www.mztv.com/pioneers.html |archive-url=https://web.archive.org/web/20130514070220/http://www.mztv.com/newframe.asp?content=http%3A%2F%2Fwww.mztv.com%2Fpioneers.html |archive-date=14 May 2013 |publisher=MZTV Museum of Television}}</ref> However, for most of the 20th century, televisions depended on the [[cathode-ray tube]] invented by [[Karl Ferdinand Braun|Karl Braun]]. The first version of such a television to show promise was produced by [[Philo Farnsworth]] and demonstrated to his family on 7 September 1927.<ref>{{cite magazine |last=Postman |first=Neil |date=29 March 1999 |title=Philo Farnsworth |url=http://www.time.com/time/time100/scientist/profile/farnsworth.html |archive-url=https://web.archive.org/web/20090930214902/http://www.time.com/time/time100/scientist/profile/farnsworth.html |archive-date=30 September 2009 |magazine=Time magazine}}</ref> After [[World War II]], interrupted experiments resumed and television became an important home entertainment broadcast medium, using [[VHF]] and [[UHF]] spectrum. [[Satellite broadcasting]] was initiated in the 1960s and moved into general industry usage in the 1970s, with DBS (Direct Broadcast Satellites) emerging in the 1980s.

Originally, all broadcasting was composed of [[analog signal]]s using [[analog transmission]] techniques but in the 2000s, broadcasters [[Digital switchover|switched]] to [[Digital signal (broadcasting)|digital signals]] using [[digital transmission]]. An analog signal is any [[continuous signal]] representing some other quantity, i.e., ''analogous'' to another quantity. For example, in an analog [[audio signal]], the instantaneous signal [[voltage]] varies continuously with the [[Sound pressure|pressure of the sound waves]].{{fact|date=January 2025}} In contrast, a [[digital signal]] represents the original time-varying quantity as a [[Sampling (signal processing)|sampled]] sequence of [[Quantization (signal processing)|quantized]] values which imposes some [[Nyquist frequency|bandwidth]] and [[dynamic range]] constraints on the representation. In general usage, broadcasting most frequently refers to the transmission of information and entertainment programming from various sources to the general public:{{fact|date=January 2025}}
* [[Analog audio]] radio (AM, FM) vs. [[Digital audio radio service|digital audio radio]] ([[HD radio]]), [[digital audio broadcasting]] (DAB), [[satellite radio]] and [[digital Radio Mondiale]] (DRM)
* [[Analog television]] vs. [[digital television]]
* [[Wireless]]

The world's technological capacity to receive information through one-way broadcast networks more than quadrupled during the two decades from 1986 to 2007, from 432 [[exabytes]] of (optimally compressed) information, to 1.9 [[zettabytes]].<ref name="HilbertLopez2011">{{cite journal |last1=Hilbert |first1=Martin |last2=López |first2=Priscila |title=The World's Technological Capacity to Store, Communicate, and Compute Information |journal=Science |date=April 2011 |volume=332 |issue=6025 |pages=60–65 |doi=10.1126/science.1200970 |pmid=21310967 }}</ref> This is the information equivalent of 55 newspapers per person per day in 1986, and 175 newspapers per person per day by 2007.<ref name="Hilbertvideo2011">{{cite web |url=https://ideas.economist.com/video/giant-sifting-sound-0 |title=video animation on The World's Technological Capacity to Store, Communicate, and Compute Information from 1986 to 2010 |publisher=Ideas.economist.com |access-date=26 December 2011 |url-status=dead |archive-url=https://web.archive.org/web/20120118072720/https://ideas.economist.com/video/giant-sifting-sound-0 |archive-date=18 January 2012  }}</ref>