Harry Nyquist (Nilsby7 February 1889 – Harlingenapril 4, 1976) was a Swedish electrical engineer who has been of great importance for the development of information theory. He has carried out important work in the field of thermal noise among other things and the digitizing of signals (the Nyquist-Shannon Sampling Theorem); See also ADC.

Harry Nyquist was born in Nilsby in Sweden. He emigrated to the United States around its 18th where he between 1912 and 1915 at the University of North Dakota a b.SC. and m.SC. in electrical engineering took out.He gained his PhD from Yale UniversityIn 1917. He then worked at AT & T until 1934. In that time he worked on telegraphy and the forerunner of the fax. In this period he came to his assertion that a signal with twice the maximum frequency to be sampled to get no information loss. In 1934 he switched course and went to work at Bell Laboratories . There he conducted research on thermal noise ("Johnson-Nyquist noise") and fed back to stability criteria of amplifiers, the "Nyquist criterion". His research to the information necessary for sending bandwidth laid the foundations for the later work of Claude Shannon that culminated in the emergence of the information theory. Nyquist left Bell Labs in 1954 after which he spent some time as a part-time consultant for the Department of Defense worked.

In 1960 he received the IRE (now IEEE) Medal of Honor "For fundamental contributions to a quantitative description of thermal noise, data transmission and negative feedback". Harry Nyquist died at the age of 87 inHarlingen (Texas).