Harry Nyquist (, ; February 7, 1889 – April 4, 1976) was a

Swedish-American Swedish Americans ( sv, svenskamerikaner) are Americans of Swedish ancestry. They include the 1.2 million Swedish immigrants during 1865–1915, who formed tight-knit communities, as well as their descendants and more recent immigrants. Today, ...

physicist and

electronic engineer Electronics engineering is a sub-discipline of electrical engineering which emerged in the early 20th century and is distinguished by the additional use of active components such as semiconductor devices to amplify and control electric current ...

who made important contributions to communication theory.

Personal life

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

Värmland Värmland () also known as Wermeland, is a '' landskap'' (historical province) in west-central Sweden. It borders Västergötland, Dalsland, Dalarna, Västmanland, and Närke, and is bounded by Norway in the west. Latin name versions are '' ...

, Sweden. He was the son of Lars Jonsson Nyqvist (b. 1847) and Katrina Eriksdotter (b. 1857). His parents had eight children: Elin Teresia, Astrid, Selma, Harry Theodor, Amelie, Olga Maria, Axel Martin and Herta Alfrida. He emigrated to the

USA The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

in 1907.

Education

He entered the

University of North Dakota The University of North Dakota (also known as UND or North Dakota) is a public research university in Grand Forks, North Dakota. It was established by the Dakota Territorial Assembly in 1883, six years before the establishment of the state of N ...

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

Ph.D. A Doctor of Philosophy (PhD, Ph.D., or DPhil; Latin: or ') is the most common degree at the highest academic level awarded following a course of study. PhDs are awarded for programs across the whole breadth of academic fields. Because it is ...

in physics at

Yale University Yale University is a Private university, private research university in New Haven, Connecticut. Established in 1701 as the Collegiate School, it is the List of Colonial Colleges, third-oldest institution of higher education in the United Sta ...

in 1917.

Career

He worked at

AT&T AT&T Inc. is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's largest telecommunications company by revenue and the third largest provider of mobile te ...

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

Bell Telephone Laboratories Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mult ...

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 Institute of Electrical and Electronics Engineers (IEEE). It has been awarded since 1917, when its first recipient was Major Edwin H. Armstrong. It is given for an exceptional contributio ...

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 {{notability, 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 - Geo ...

of the

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

"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, non-governmental organization. The National Academy of Engineering is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of ...

'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 The Rufus Oldenburger Medal is an award given by the American Society of Mechanical Engineers recognizing significant contributions and outstanding achievements in the field of automatic control. It was established in 1968 in the honor of Rufus O ...

from the American Society of Mechanical Engineers. As reported in The Idea Factory, 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.” (Pg. 135) Nyquist lived in

Pharr, Texas Pharr is a city in Hidalgo County, Texas, United States. As of the 2010 census, the city population was 70,400, and in 2019, the estimated population was 79,112. Pharr is connected by bridge to the Mexican city of Reynosa, Tamaulipas. Pharr i ...

after his retirement, and died in Harlingen, Texas on April 4, 1976.

Technical contributions

As an engineer at Bell Laboratories, Nyquist did important work on thermal noise ("

Johnson–Nyquist noise Johnson–Nyquist noise (thermal noise, Johnson noise, or Nyquist noise) is the electronic noise generated by the thermal agitation of the charge carriers (usually the electrons) inside an electrical conductor at equilibrium, which happens reg ...

"), the stability of feedback

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 may increase the power significantly, or its main effect may be to boost t ...

s, telegraphy, facsimile, television, and other important communications problems. With

Herbert E. Ives Herbert Eugene Ives (July 31, 1882 – November 13, 1953) was a scientist and engineer who headed the development of facsimile and television systems at AT&T in the first half of the twentieth century. He is best known for the 1938 Ives–Stilwel ...

, 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 all 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, and cryptographer known as a "father of information theory". As a 21-year-old master's degree student at the Massachusetts Inst ...

, 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 Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...

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 a theorem in the field of signal processing which serves as a fundamental bridge between continuous-time signals and discrete-time signals. It establishes a sufficient condition for a sample rate that per ...

Terms named for Harry Nyquist

Nyquist rate In signal processing, the Nyquist rate, named after Harry Nyquist, is a value (in units of samples per second or hertz, Hz) equal to twice the highest frequency ( bandwidth) of a given function or signal. When the function is digitized at a hi ...

: sampling rate twice the bandwidth of the signal's waveform being sampled; sampling faster than this rate assures 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 sampler, which converts a continuous function or signal into a discrete sequence. In units of cycles per second ( Hz), it ...

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

Nyquist filter A Nyquist filter is an electronic filter used in TV receivers to equalize the video characteristics. The filter is named after the Swedish–US engineer Harry Nyquist (1889–1976). VSB In analogue TV broadcasting the visual radio frequency (RF ...

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 Har ...

* Nyquist ISI criterion *

Nyquist (programming language) Nyquist is a programming language for sound synthesis and analysis based on the Lisp programming language. It is an extension of the XLISP dialect of Lisp, and is named after Harry Nyquist. With Nyquist, the programmer designs musical instruments ...

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 his ...

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