Background
Nyquist was born in the Stora Kil parish of Nilsby, Värmland, Sweden. He was the son of Lars Jonsson Nyqvist (b 1847) and Katrina Eriksdotter (b 1857).
Nyquist was born in the Stora Kil parish of Nilsby, Värmland, Sweden. He was the son of Lars Jonsson Nyqvist (b 1847) and Katrina Eriksdotter (b 1857).
He entered the University of North Dakota in 1912 and received Bachelor of Surgery and Master of Surgery degrees in electrical engineering in 1914 and 1915, respectively. He received a Doctor of Philosophy in physics at Yale University in 1917.
He worked at American Telephone & Telegraph Company"s Department of Development and Research from 1917 to 1934, and continued when it became Bell Telephone Laboratories that year, until his retirement in 1954. Nyquist lived in Pharr, Texas after his retirement, and died in Harlingen, Texas on April 4, 1976. As an engineer at Bell Laboratories, Nyquist did important work on thermal noise ("Johnson–Nyquist noise"), the stability of feedback amplifiers, telegraphy, facsimile, television, and other important communications problems.
With Herbert East. Ives, he helped to develop American Telephone & Telegraph Company"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 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. 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).
This rule is essentially a dual of what is now known as the Nyquist–Shannon sampling theorem.