John Renshaw Carson(June 28, 1886 – October 31, 1940) was an American transmission theorist for early communications systems. He inventedsingle-sideband modulationand developed theCarson bandwidth rulefor estimatingfrequency modulation(FM) bandwidth. In 2013 Carson was inducted into the Electronic Design Hall of Fame for his contributions to communications.[1]
Biography
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Carson was born inPittsburgh, Pennsylvania,and together with his twin brother Joseph attendedPrinceton University,graduating in 1907 with a Bachelor of Science degree. John attended theMassachusetts Institute of Technology1907–1908, before returning to Princeton to receive hiselectrical engineeringdegree in 1909 and a Master of Science degree in 1912. From 1912 to 1914 Carson was an instructor in Electrical Engineering and Physics at Princeton, but in 1913 was offered a position atAmerican Telephone & Telegraph(AT&T), and in 1914 left the university.[3]
At AT&T, Carson was involved in earlyradio telephoneexperiments. In 1915 he invented[4]single-sideband modulationto transmit multiple telephone calls simultaneously on a single electrical circuit, and was responsible for installing the first such system betweenPittsburghandBaltimore.In 1922 he published a mathematical treatment offrequency modulation(FM), which introduced theCarson bandwidth rule.In his 1922 paper, Carson presented a negative opinion of narrowband FM, which occurs when the maximum frequency swing is made narrower than the audio bandwidth. Later,Edwin Armstrongmanaged to demonstrate that FM can be advantageous if the frequency swing is significantly wider than the audio bandwidth. From 1917 to 1925 Carson analyzed the effects of filters onamplitude modulationviaoperational calculus,thus allowing telephone system designers to predictcrosstalkin multiple calls over a single pair of wires. He published a series of papers on this subject in theBell System Technical Journal,culminating in his 1926 bookElectrical Circuit Theory and Operational Calculus.
From 1925 to 1940 Carson worked forBell Telephone Laboratoriesas a mathematician and electrical engineer. Notable work during this era included his mathematical analysis ofGeorge C. Southworth's 1932waveguideexperiments.
Carson received the 1924IRE Morris N. Liebmann Memorial Award"in recognition of his valuable contributions to alternating current circuit theory and, in particular, to his investigations of filter systems and of single side band telephony." He received an honorary Doctor of Science degree fromBrooklyn Polytechnic Institutein 1937, and the 1939Elliott Cresson Medalfrom theFranklin Institute.His undergraduate letters are archived atPrinceton University.
Patent
edit- U.S. patent 1,449,382:John Carson/AT&T: "Method and Means for Signaling with High Frequency Waves" filed on December 1, 1915; granted on March 27, 1923
Selected works
edit- 1921: "Wave Propagation over Parallel Wires: The Proximity effect",Philosophical Magazine,volume IXLI, pages 607–633.
- 1922: "Notes on the Theory of Modulation",Proceedings of the Institute of Radio Engineers,volume 10, issue 1, pages 57–64.
- 1924:A Generalization of Reciprocal Theorem,Bell System Technical Journal3: 393–399.
- 1925:Selective Circuits and Static Interference,Bell System Technical Journal,4:265.
- 1926:Wave Propagation in Overhead Wires with Ground Return,Bell System Technical Journal,5: 539.
- 1926:Electrical Circuit Theory and Operational Calculus,New York: McGraw–Hill.
- 1926:The Heaviside Operational Calculus,Bulletin of the American Mathematical Society32(1):43–68, link fromProject Euclid.
- 1936: (with S. P. Mead and S. A. Schelkunoff)Hyper-Frequency Waveguides: Mathematical Theory,Bell System Technical Journal15: 310–333.
See also
editReferences
edit- ^Frenzel, Lou."John Renshaw Carson: Pioneer Ruled Modulation's Earliest Innovations".Electronic Design.Retrieved9 November2018.
- ^"Einstein and Steinmetz with group".New York Heritage Digital Collections.Retrieved9 November2018.
- ^Frenzel, Lou."John Renshaw Carson: Pioneer Ruled Modulation's Earliest Innovations".Electronic Design.Retrieved9 November2018.
- ^US 1449382John Carson/AT&T: "Method and Means for Signaling with High Frequency Waves" filed on December 1, 1915; granted on March 27, 1923
Sources
edit- John & Robb Carson Lettersin Mudd Manuscript Library ofPrinceton University LibraryArchives.
- Brittain, J.E., "John R. Carson and the conservation of radio spectrum",Proceedings of the IEEE,volume 84, issue 6, June 1996, pages 909–910.
- Mario Lucertini,Ana Millán Gasca,F. Nicolò,Technological Concepts and Mathematical Models in the Evolution of Modern Engineering Systems,Birkhäuser, 2004, pages 114–117.ISBN3-7643-6940-X.
- Julie K. Petersen,Fiber Optics Illustrated Dictionary,CRC Press, 2003, page 264.ISBN0-8493-1349-X.