|
Otto Julius Zobel (October 20, 1887 – January 1970) was an electrical engineer who worked for the American Telephone & Telegraph Company (AT&T) in the early part of the 20th century. Zobel's work on filter design was revolutionary and led, in conjunction with the work of John R. Carson, to significant commercial advances for AT&T in the field of frequency division multiplex (FDM) telephone transmissions.〔Bray, p. 62.〕 Although much of Zobel's work has been superseded by more modern filter designs, it remains the basis of filter theory and his papers are still referenced today. Zobel invented the m-derived filter〔White, G, ("The Past" ), ''BT Technology Journal'', Vol 18, No 1, pp. 107–132, January 2000 .〕 and the constant-resistance filter,〔Zobel, O J, ''Distortion Compensator'', , filed 26 June 1924, issued 12 Feb 1929.〕 which remains in use. Zobel and Carson helped to establish the nature of noise in electric circuits, concluding that—contrary to mainstream belief〔Schwartz, p. 9.〕—it is not even theoretically possible to filter out noise entirely and that noise will always be a limiting factor in what is possible to transmit.〔 Thus, they anticipated the later work of Claude Shannon, who showed how the theoretical information rate of a channel is related to the noise of the channel. ==Life== Otto Julius Zobel was born on October 20, 1887 in Ripon, Wisconsin.〔Poggendorff, J C, ''Poggendorffs biographisch-literarisches handwörterbuch für mathematik, astronomie, physik mit geophysik, chemie, kristallographie und verwandte wissensgebiete'', p.2969, Verlag Chemie, g.m.b.h. 1940〕 He first studied at Ripon College, where he received his BA in 1909 with a thesis〔"(Student theses )", Ripon College.〕 on ''Theoretical and experimental treatment of electrical condensers''. He later received a Distinguished Alumnus Award from Ripon.〔"(Distinguished Alumni Award Recipients )", Ripon College.〕 He then went to the University of Wisconsin and graduated with an MA in physics in 1910. Zobel stayed at the University of Wisconsin as a physics instructor from 1910 to 1915, and graduated with his PhD in 1914; his dissertation concerned "Thermal Conduction and Radiation". This followed his 1913 co-authoring of a book on the subject of geophysical thermodynamics.〔Leonard ''et al.'', ''passim''〕 From 1915 to 1916 he taught physics at the University of Minnesota.〔〔American Telephone and Telegraph Company, ''The Bell System Technical Journal'', p. 686, 1922〕 Having moved to Maplewood, New Jersey, he joined AT&T in 1916, where he worked on transmission techniques. In 1926, still with the company, he moved to New York and in 1934, he transferred to Bell Telephone Laboratories (Bell Labs), the research organisation created jointly by AT&T and Western Electric a few years earlier.〔Seising, R, (''The Fuzzification of Systems'' ), 2007, Springer Berlin / Heidelberg ISBN 3-540-71794-3〕 The last of his prolific list of patents〔Zobel, O J, ''Impedance Transformer'', , filed 30 Sept 1952, issued 16 Oct 1956.〕〔Zobel, O J, ''Microwave Filter'', , filed 20 April 1950, issued 23 Dec 1952.〕 occurred for Bell Labs in the 1950s, by which time he was residing in Morristown, New Jersey.〔Record of addresses given in patents〕 He died there in January 1970.〔Social Security Death Index database query through (WorldVitalRecords.com )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Otto Julius Zobel」の詳細全文を読む スポンサード リンク
|