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Harry Nyquist

 

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Harry Nyquist



 
 
Harry Nyquist ( Harry Theodor Nyqvist; pron. [n?:kv?st], not [na?kw?st] as often pronounced), (February 7, 1889 – April 4, 1976) was an important contributor to information theory
Information theory

Information theory is a branch of applied mathematics and electrical engineering involving the quantification of information. Historically, information theory was developed by Claude E....
.

ist was born in the Stora Kil parish of Nilsby, Värmland
Värmland

is a Provinces of Sweden or landskap in the west of middle Sweden. It borders V?sterg?tland, Dalsland, Dalarna, V?stmanland and N?rke. It is also bounded by Norway in the west....
, Sweden
Sweden

Sweden , officially the Kingdom of Sweden , is a Nordic countries on the Scandinavian Peninsula in Northern Europe. Sweden has land borders with Norway to the west and Finland to the northeast, and it is connected to Denmark by the ?resund Bridge in the south....
. He was the son of Lars Jonsson Nyqvist (b. 1847) and Katrina Eriksdotter (b. 1857). His parents had seven children: Elin Teresia, Astrid, Selma, Harry Theodor, Aemelie, Olga Maria, and Axel.






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Harry Nyquist ( Harry Theodor Nyqvist; pron. [n?:kv?st], not [na?kw?st] as often pronounced), (February 7, 1889 – April 4, 1976) was an important contributor to information theory
Information theory

Information theory is a branch of applied mathematics and electrical engineering involving the quantification of information. Historically, information theory was developed by Claude E....
.

Personal life

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

is a Provinces of Sweden or landskap in the west of middle Sweden. It borders V?sterg?tland, Dalsland, Dalarna, V?stmanland and N?rke. It is also bounded by Norway in the west....
, Sweden
Sweden

Sweden , officially the Kingdom of Sweden , is a Nordic countries on the Scandinavian Peninsula in Northern Europe. Sweden has land borders with Norway to the west and Finland to the northeast, and it is connected to Denmark by the ?resund Bridge in the south....
. He was the son of Lars Jonsson Nyqvist (b. 1847) and Katrina Eriksdotter (b. 1857). His parents had seven children: Elin Teresia, Astrid, Selma, Harry Theodor, Aemelie, Olga Maria, and Axel. None of the seven children were Christened. He emigrated to the USA
United States

The United States of America is a Federal government constitutional republic comprising U.S. state and a federal district. The country is situated mostly in central North America, where its Contiguous United States and Washington, D.C., the Capital districts and territories, lie between the Pacific Ocean and Atlantic Oceans, Borders of the U...
 in 1907.

Education


He entered the University of North Dakota
University of North Dakota

The University of North Dakota is a public university in Grand Forks, North Dakota, United States. Established by the Dakota Territory Assembly in 1883, six years before the establishment of the U.S....
 in 1912 and received the B.S. and M.S. degrees in electrical engineering in 1914 and 1915, respectively. He received a Ph.D.
Doctor of Philosophy

Doctor of Philosophy, abbreviated Ph.D. or PhD for the Latin , meaning "teacher of philosophy", is an postgraduate academic degree awarded by University....
 in physics at Yale University
Yale University

Yale University is a private university in New Haven, Connecticut. Founded in 1701 as the Collegiate School, Yale is the Colonial Colleges institution of higher education in the United States and is a member of the Ivy League....
 in 1917.

Career

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

Nyquist received the IRE Medal of Honor
IEEE Medal of Honor

The IEEE Medal of Honor is the highest recognition of the Institute of Electrical and Electronics Engineers . It has been awarded since 1917, when its first recipient was Major Edwin H....
 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
Franklin Institute

Founded in honor of Benjamin Franklin, The Franklin Institute is a museum in Philadelphia, Pennsylvania, and one of the oldest and premier centers of science education and development in the United States....
 "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
National Academy of Engineering

The United States National Academy of Engineering is a private, non-profit institution which was founded in 1964, under the same congressional act that led to the founding of the United States National Academy of Sciences, signed by Abraham Lincoln, in 1863....
's fourth Founder's Medal "in recognition of his many fundamental contributions to engineering."

Nyquist lived in Pharr, Texas
Pharr, Texas

Pharr is a city in Hidalgo County, Texas, Texas, United States. As of the 2000 United States Census, the city population was 46,660. Pharr is connected by Pharr-Reynosa International Bridge to the Mexico city of Reynosa....
 after his retirement, and died in Harlingen, Texas
Harlingen, Texas

Harlingen is a city in Cameron County, Texas in the heart of the Rio Grande Valley of south Texas, United States. The city covers more than 34 sq mi and is the second largest city in Cameron County and the third largest in the Rio Grande Valley after Brownsville, Texas and McAllen, 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

Johnson?Nyquist noise is the electronic noise noise generated by the thermal agitation of the charge carriers inside an electrical conductor at equilibrium, which happens regardless of any applied voltage....
"), the stability of feedback
Feedback

Feedback describes the situation when output from an event or phenomenon in the past will influence the same event/phenomenon in the present or future....
 amplifier
Amplifier

Generally, an amplifier or simply amp, is any machine that changes, usually increases, the amplitude of a Signal . The "signal" is usually voltage or current....
s, telegraphy, facsimile, television, and other important communications problems. With Herbert E. Ives
Herbert E. Ives

Herbert Eugene Ives 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 helped to develop AT&T
AT&T

AT&T Inc. is the largest US provider of both local and long distance telephone services, and Digital subscriber line Internet access. AT&T is the second largest provider of wireless service in the United States, with over 77 million wireless customers, and more than 150 million total customers....
's first facsimile machines that were made public in 1924. In 1932, he published a classical paper on stability of feedback amplifiers. Nyquist stability criterion
Nyquist stability criterion

The Nyquist stability criterion, named after Harry Nyquist, provides a simple test for BIBO stability of a closed-loop control system by examining the open-loop system's Nyquist plot....
 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, which led to the development of information theory
Information theory

Information theory is a branch of applied mathematics and electrical engineering involving the quantification of information. Historically, information theory was developed by Claude E....
.

In 1927 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. Nyquist published his results in the paper Certain topics in Telegraph Transmission Theory (1928). This rule is essentially a dual
Duality (mathematics)

In mathematics, duality has numerous meanings. Generally speaking, duality is a metamathematics Involution . Some duality concepts are closely related and there are explicit theorems governing their relationships....
 of what is now known as the Nyquist–Shannon sampling theorem
Nyquist–Shannon sampling theorem

The Nyquist?Shannon sampling theorem is a fundamental result in the field of information theory, in particular telecommunications and signal processing....
.

See also

  • Nyquist plot
    Nyquist plot

    A Nyquist plot is used in control system and signal processing for assessing the stability of a system with feedback. It is represented by a graph in polar coordinates in which the gain and phase of a frequency response are plotted....
  • Nyquist–Shannon sampling theorem
    Nyquist–Shannon sampling theorem

    The Nyquist?Shannon sampling theorem is a fundamental result in the field of information theory, in particular telecommunications and signal processing....
  • Nyquist frequency
    Nyquist frequency

    The Nyquist frequency, named after the Swedish-American engineer Harry Nyquist or the Nyquist?Shannon sampling theorem, is half the sampling frequency of a discrete signal processing system....
  • Nyquist stability criterion
    Nyquist stability criterion

    The Nyquist stability criterion, named after Harry Nyquist, provides a simple test for BIBO stability of a closed-loop control system by examining the open-loop system's Nyquist plot....
  • Nyquist ISI criterion
    Nyquist ISI criterion

    In communications, the Nyquist ISI criterion describes the conditions which, when satisfied by a Channel , result in no intersymbol interference or ISI....
  • Johnson–Nyquist noise
    Johnson–Nyquist noise

    Johnson?Nyquist noise is the electronic noise noise generated by the thermal agitation of the charge carriers inside an electrical conductor at equilibrium, which happens regardless of any applied voltage....


External links

  • with photo of Nyquist with John R. Pierce and Rudy Kompfner