Editing Harry Nyquist

{{short description|Swedish-American physicist and electrical engineer (1889–1976)}}
{{Infobox scientist
| name              = Harry Nyquist
| image             = Harry Nyquist.jpg
| image_size        = 200px
| caption           = Harry Nyquist
| birth_date        = {{birth date|1889|2|7}}
| birth_place       = Nilsby, Stora Kil, [[Värmland]], [[Sweden]]
| death_date        = {{death date and age|1976|4|4|1889|2|7}}
| death_place       = [[Harlingen, Texas|Harlingen]], [[Texas]], U.S.
| citizenship       = Swedish / American
| nationality       = Swedish
| fields            = [[Electronic engineer]]
| workplaces        = [[Bell Laboratories]]
| alma_mater        = [[Yale University]]<br>[[University of North Dakota]]
| doctoral_advisor  = [[Henry Andrews Bumstead]]
| academic_advisors =
| doctoral_students = 
| notable_students  = 
| known_for         = [[Nyquist–Shannon sampling theorem]]<br>[[Nyquist rate]]<br>[[Johnson–Nyquist noise]]<br>[[Nyquist stability criterion]]<br>[[Nyquist ISI criterion]]<br>[[Nyquist plot]]<br>[[Nyquist frequency]]<br>[[Nyquist filter]]<br>[[Fluctuation dissipation theorem]]
| author_abbrev_bot = 
| author_abbrev_zoo = 
| influences        = 
| influenced        = 
| awards            = [[IEEE Medal of Honor]] (1960)<br>[[Stuart Ballantine Medal]] (1960)<br>[[Rufus Oldenburger Medal]] (1975)
| religion          = 
| signature         = <!--(filename only)-->
| footnotes         =  
}}

'''Harry Nyquist''' ({{IPAc-en|ˈ|n|aɪ|k|w|ɪ|s|t}}, {{IPA|sv|ˈnŷːkvɪst|lang}}; February 7, 1889 – April 4, 1976) was a [[Swedish-American]] physicist and [[electronic engineer]] who made important contributions to [[communication theory]].<ref>{{cite journal|title=Harry Nyquist|journal=Physics Today|date=June 1976|volume=29|issue=6|pages=64|doi=10.1063/1.3023534|bibcode=1976PhT....29f..64.|doi-access=free}}</ref>

==Personal life==
Nyquist was born in the village Nilsby of the parish Stora Kil, [[Värmland]], [[Sweden]]. He was the son of Lars Jonsson Nyqvist (1847–1930) and Catarina (or Katrina) Eriksdotter (1857–1920). His parents had eight children: Elin Teresia, Astrid, Selma, Harry Theodor, Amelie, Olga Maria, Axel Martin and Herta Alfrida.<ref>"Sveriges befolkning 1900" [CD-ROM]: Nyqvist, Harry</ref> He immigrated to the [[United States]] in 1907.

==Education==
He entered the [[University of North Dakota]] in 1912 and received B.S. and M.S. degrees in electrical engineering in 1914 and 1915, respectively. He received a [[Doctor of Philosophy|Ph.D.]] in physics at [[Yale University]] in 1917.

==Career==
He worked at [[AT&T Corp.|AT&T]]'s Department of Development and Research from 1917 to 1934, and continued when it became [[Bell Laboratories|Bell Telephone Laboratories]] that year, until his retirement in 1954.

Nyquist received the [[IEEE Medal of Honor|IRE Medal of Honor]] in 1960 for "fundamental contributions to a quantitative understanding of thermal noise, data transmission and negative feedback."  
In October 1960 he was awarded the [[Stuart Ballantine Medal]] of the [[Franklin Institute]] "for his theoretical analyses and practical inventions in the field of communications systems during the past forty years including, particularly, his original work in the theories of telegraph transmission, thermal noise in electric conductors, and in the history of feedback systems." 
In 1969 he was awarded the [[National Academy of Engineering]]'s fourth Founder's Medal "in recognition of his many fundamental contributions to engineering."
In 1975 Nyquist received together with [[Hendrik Bode]] the [[Rufus Oldenburger Medal]] from the [[American Society of Mechanical Engineers]].<ref>{{cite web|url=http://www.asme.org/about-asme/honors-awards/achievement-awards/rufus-oldenburger-medal |title=Rufus Oldenburger Medal |publisher=[[American Society of Mechanical Engineers]] |access-date={{Format date|2013|2|21}}}}</ref>

As reported in ''The Idea Factory: Bell Labs and the Great Age of American Innovation'', the Bell Labs patent lawyers wanted to know why some people were so much more productive (in terms of patents) than others. After crunching a lot of data, they found that the only thing the productive employees had in common (other than having made it through the Bell Labs hiring process) was that "Workers with the most patents often shared lunch or breakfast with a Bell Labs electrical engineer named Harry Nyquist. It wasn't the case that Nyquist gave them specific ideas. Rather, as one scientist recalled, 'he drew people out, got them thinking'" (p.&nbsp;135).

Nyquist lived in [[Pharr, Texas]] after his retirement, and died in [[Harlingen, Texas]] on April 4, 1976.

== Technical contributions==
[[File:UND Nyquist Memorial.JPG|thumb|Memorial to Harry Nyquist at the University of North Dakota's College of Engineering and Mines]]As an engineer at Bell Laboratories, Nyquist did important work on thermal noise ("[[Johnson–Nyquist noise]]"),<ref>{{cite journal | last=Nyquist | first=H. | title=Thermal Agitation of Electric Charge in Conductors | journal=Physical Review | publisher=American Physical Society (APS) | volume=32 | issue=1 | date=1928-07-01 | issn=0031-899X | doi=10.1103/physrev.32.110 | pages=110–113| bibcode=1928PhRv...32..110N }}</ref> the stability of [[feedback]] [[amplifier]]s, telegraphy, [[fax|facsimile]], television, and other important communications problems.  With [[Herbert E. Ives]], he helped to develop AT&T's first facsimile machines that were made public in 1924. In 1932, he published a classic paper on stability of feedback amplifiers.<ref>{{cite journal|first=H. |last=Nyquist|title=Regeneration theory|journal=Bell System Technical Journal|volume=11|pages=126–147|year= 1932|doi=10.1002/j.1538-7305.1932.tb02344.x|s2cid=115002788 |url=https://archive.org/details/bstj11-1-126}}</ref>  The [[Nyquist stability criterion]] can now be found in many textbooks on feedback control theory.

His early theoretical work on determining the bandwidth requirements for transmitting information laid the foundations for later advances by [[Claude Shannon]], which led to the development of [[information theory]].  In particular, Nyquist determined that the number of independent pulses that could be put through a telegraph channel per unit time is limited to twice the [[Bandwidth (signal processing)|bandwidth]] of the channel, and published his results in the papers ''Certain factors affecting telegraph speed'' (1924)<ref>{{cite journal|last=Nyquist|first= Harry|title=Certain factors affecting telegraph speed|journal=[[Bell System Technical Journal]]|volume= 3|pages=324–346|year=1924|issue= 2|doi= 10.1002/j.1538-7305.1924.tb01361.x|s2cid= 51630538|url=https://archive.org/details/bstj3-2-324}}</ref> and ''Certain topics in Telegraph Transmission Theory'' (1928).<ref>{{cite journal | last=Nyquist | first=H. | title=Certain Topics in Telegraph Transmission Theory | journal=Transactions of the American Institute of Electrical Engineers | publisher=Institute of Electrical and Electronics Engineers (IEEE) | volume=47 | issue=2 | year=1928 | issn=0096-3860 | doi=10.1109/t-aiee.1928.5055024 | pages=617–644| bibcode=1928TAIEE..47..617N }} [https://web.archive.org/web/20060706192816/http://www.loe.ee.upatras.gr/Comes/Notes/Nyquist.pdf Reprint as classic paper in: ''Proc. IEEE, Vol. 90, No. 2, Feb 2002''].</ref>  This rule is essentially a [[Duality (mathematics)|dual]] of what is now known as the [[Nyquist–Shannon sampling theorem]].

==Terms named for Harry Nyquist==
* [[Nyquist rate]]: sampling rate twice the bandwidth of the signal's waveform being sampled; sampling at a rate that is equal to, or faster, than this rate ensures that the waveform can be reconstructed accurately.
* [[Nyquist frequency]]: half the sample rate of a system; signal frequencies below this value are unambiguously represented.
* [[Nyquist filter]]
* [[Nyquist plot]]
* [[Nyquist ISI criterion]]
* [[Nyquist (programming language)]]
* [[Nyquist stability criterion]]

==References==
{{reflist}}

==External links==
*{{Commons category-inline}}
* [http://www.ieeeghn.org/wiki/index.php/Harry_Nyquist IEEE Global History Network page about Nyquist]
* [https://web.archive.org/web/20111002150807/http://www.trendcomms.com/multimedia/training/broadband%20networks/web/main/m1/temari/seccio5/nyquist.htm Nyquist criterion page] with photo of Nyquist with [[John R. Pierce]] and [[Rudy Kompfner]]
* [https://web.archive.org/web/20140714233133/http://userspages.uob.edu.bh/ebrgallaf/ASMENyquistLecture2005.pdf K.J.Astrom: Nyquist and his seminal papers, 2005 presentation]
* [http://www.eleceng.adelaide.edu.au/Personal/dabbott/publications/EDU_abbott1996.pdf Nyquist biography, p. 2] {{Webarchive|url=https://web.archive.org/web/20131228234916/http://www.eleceng.adelaide.edu.au/Personal/dabbott/publications/EDU_abbott1996.pdf |date=2013-12-28 }}

{{IEEE Medal of Honor Laureates 1951–1975}}

{{Authority control}}

{{DEFAULTSORT:Nyquist, Harry}}
[[Category:1889 births]]
[[Category:1976 deaths]]
[[Category:People from Kil Municipality]]
[[Category:American electronics engineers]]
[[Category:AT&T people]]
[[Category:Control theorists]]
[[Category:IEEE Medal of Honor recipients]]
[[Category:American information theorists]]
[[Category:Information theory]]
[[Category:Scientists at Bell Labs]]
[[Category:University of North Dakota alumni]]
[[Category:Yale University alumni]]
[[Category:Swedish emigrants to the United States]]
[[Category:People from Pharr, Texas]]
[[Category:Mathematicians from Texas]]
[[Category:20th-century American engineers]]
[[Category:Fellows of the American Physical Society]]