Harry Nyquist (, ; February 7, 1889 – April 4, 1976) was a Swedish-American physicist and electronic engineer who made important contributions to

communication theory Communication theory is a proposed description of communication phenomena, the relationships among them, a storyline describing these relationships, and an argument for these three elements. Communication theory provides a way of talking about a ...

Personal life

Nyquist was born in the village Nilsby of the parish Stora Kil,

Värmland Värmland () is a ''Provinces of Sweden, landskap'' (historical province) in west-central Sweden. It borders Västergötland, Dalsland, Dalarna, Västmanland, and Närke, and is bounded by Norway in the west. Name Several Latinized version ...

Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...

. 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. He immigrated to the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

in 1907.

Education

He entered the

University of North Dakota The University of North Dakota (UND) is a Public university, public research university in Grand Forks, North Dakota, United States. It was established by the Dakota Territory, Dakota Territorial Assembly in 1883, six years before the establishm ...

in 1912 and received B.S. and M.S. degrees in electrical engineering in 1914 and 1915, respectively. He received a Ph.D. in physics at

Yale University Yale University is a Private university, private Ivy League research university in New Haven, Connecticut, United States. Founded in 1701, Yale is the List of Colonial Colleges, third-oldest institution of higher education in the United Stat ...

in 1917.

Career

He worked at

AT&T AT&T Inc., an abbreviation for its predecessor's former name, the American Telephone and Telegraph Company, is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the w ...

's Department of Development and Research from 1917 to 1934, and continued when it became

Bell Telephone Laboratories Nokia Bell Labs, commonly referred to as ''Bell Labs'', is an American industrial research and development company owned by Finnish technology company Nokia. With headquarters located in Murray Hill, New Jersey, Murray Hill, New Jersey, the compa ...

that year, until his retirement in 1954. Nyquist received the

IRE Medal of Honor The IEEE Medal of Honor is the highest recognition of the American Institute of Electrical and Electronics Engineers (IEEE). It has been awarded since 1917, and is presented to an individual or team of up to three who have made exceptional contri ...

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 {{Refimprove, date=February 2018 The Stuart Ballantine Medal was a science and engineering award presented by the Franklin Institute, of Philadelphia, Pennsylvania, USA. It was named after the US inventor Stuart Ballantine. Laureates *1947 - Ge ...

of the

Franklin Institute The Franklin Institute is a science museum and a center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and wikt:statesman, statesman Benjamin Franklin. It houses the Benjamin Franklin ...

"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 The National Academy of Engineering (NAE) is an American Nonprofit organization, nonprofit, NGO, non-governmental organization. It is part of the National Academies of Sciences, Engineering, and Medicine (NASEM), along with the National Academ ...

's fourth Founder's Medal "in recognition of his many fundamental contributions to engineering." In 1975 Nyquist received together with

Hendrik Bode Hendrik Wade Bode ( , ;Van Valkenburg, M. E. University of Illinois at Urbana-Champaign, "In memoriam: Hendrik W. Bode (1905-1982)", IEEE Transactions on Automatic Control, Vol. AC-29, No 3., March 1984, pp. 193–194. Quote: "Something should be ...

the Rufus Oldenburger Medal from the

American Society of Mechanical Engineers The American Society of Mechanical Engineers (ASME) is an American professional association that, in its own words, "promotes the art, science, and practice of multidisciplinary engineering and allied sciences around the globe" via "continuing edu ...

. 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. 135). Nyquist lived in

Pharr, Texas Pharr is a city in Hidalgo County, Texas, United States. As of the 2020 census, the city population was 79,715, and in 2022, the estimated population was 80,187. Pharr is connected by bridge to the Mexican city of Reynosa, Tamaulipas. Pharr is ...

after his retirement, and died in

Harlingen, Texas Harlingen ( ) is a city in Cameron County, Texas, Cameron County in the central region of the Rio Grande Valley (Texas), Rio Grande Valley of the southern part of the U.S. state of Texas, about from the coast of the Gulf of Mexico. The city co ...

on April 4, 1976.

Technical contributions

As an engineer at Bell Laboratories, Nyquist did important work on thermal noise (" Johnson–Nyquist noise"), the stability of

feedback Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause and effect that forms a circuit or loop. The system can then be said to ''feed back'' into itself. The notion of cause-and-effect has to be handle ...

amplifier An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It is a two-port electronic circuit that uses electric power from a power su ...

s, telegraphy,

facsimile A facsimile (from Latin ''fac simile'', "to make alike") is a copy or reproduction of an old book, manuscript, map, art print, or other item of historical value that is as true to the original source as possible. It differs from other forms of r ...

, 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. The

Nyquist stability criterion In control theory and stability theory, the Nyquist stability criterion or Strecker–Nyquist stability criterion, independently discovered by the German electrical engineer at Siemens in 1930 and the Swedish-American electrical engineer Harry ...

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 Claude Elwood Shannon (April 30, 1916 – February 24, 2001) was an American mathematician, electrical engineer, computer scientist, cryptographer and inventor known as the "father of information theory" and the man who laid the foundations of th ...

, which led to the development of

information theory Information theory is the mathematical study of the quantification (science), quantification, Data storage, storage, and telecommunications, communication of information. The field was established and formalized by Claude Shannon in the 1940s, ...

. 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 of the channel, and published his results in the papers ''Certain factors affecting telegraph speed'' (1924) and ''Certain topics in Telegraph Transmission Theory'' (1928).Reprint as classic paper in: ''Proc. IEEE, Vol. 90, No. 2, Feb 2002''
This rule is essentially a dual of what is now known as the

Nyquist–Shannon sampling theorem The Nyquist–Shannon sampling theorem is an essential principle for digital signal processing linking the frequency range of a signal and the sample rate required to avoid a type of distortion called aliasing. The theorem states that the sample r ...

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 In signal processing, the Nyquist frequency (or folding frequency), named after Harry Nyquist, is a characteristic of a Sampling (signal processing), sampler, which converts a continuous function or signal into a discrete sequence. For a given S ...

: half the sample rate of a system; signal frequencies below this value are unambiguously represented. * Nyquist filter *

Nyquist plot In control theory and stability theory, the Nyquist stability criterion or Strecker–Nyquist stability criterion, independently discovered by the German electrical engineer at Siemens in 1930 and the Swedish-American electrical engineer Harry ...

Nyquist ISI criterion In communications, the Nyquist ISI criterion describes the conditions which, when satisfied by a communication channel (including responses of transmit and receive filters), result in no intersymbol interference or ISI. It provides a method for ...

* Nyquist (programming language) *

References

External links

*
IEEE Global History Network page about Nyquist

with photo of Nyquist with

John R. Pierce John Robinson Pierce (March 27, 1910 – April 2, 2002), was an American engineer and author. He did extensive work concerning radio communication, microwave technology, computer music, psychoacoustics, and science fiction. Additionally to ...

and Rudy Kompfner
K.J.Astrom: Nyquist and his seminal papers, 2005 presentation

Nyquist biography, p. 2
{{DEFAULTSORT:Nyquist, Harry 1889 births 1976 deaths People from Kil Municipality American electronics engineers AT&T people Control theorists IEEE Medal of Honor recipients American information theorists Information theory Scientists at Bell Labs University of North Dakota alumni Yale University alumni Swedish emigrants to the United States People from Pharr, Texas Mathematicians from Texas 20th-century American engineers Fellows of the American Physical Society