Sixty years ago this month, the PROCEEDINGS OF THE lNSTITUTE OF RADIO ENGINEERS (IRE) included a paper by Wilmer L. Barrow on the analysis of nonlinear vacuum-tube circuits subjected to large signals. At the time he was teaching communications engineering at the Massachusetts Institute of Technology (MIT) and also was engaged in research at the Round Hill facility of MIT. During the 1930’s, Barrow and his MIT students made important contributions to microwave engineering, especially in the investigation of waveguides and horn antennas. He was the author or coauthor of 14 technical papers published in the PROCEEDINGS during 1932-1940.

In his August 1934 paper, Barrow pointed out that there were numerous cases such as modulators and demodulators where nonlinear circuits had emerged as a “problem of fundamental importance.” He explained that the theory of linear circuits with small signals applied was much more developed. He presented a method for nonlinear circuit analysis which involved the use of a trigonometric polynomial to approximate the current-voltage characteristic of a vacuum tube. He stated that this approach permitted the calculation of performance with “much less labor” than alternative methods. He included examples where he had used his method to determine harmonic distortion in amplifiers, modulators, and detectors. His basic equation was expressed in terms of a Bessel function series and he concluded that the method should be applicable to a wide range of problems.

Barrow was born in 1903 in Louisiana and graduated in electrical engineering from Louisiana State University in 1926. He earned the M.S. degree at MIT in 1929 and then was awarded a graduate fellowship which allowed him to study in Germany, where he received the Ph.D. degree from the Technische Hochschule in Munich in 1931. He then returned to MIT, where he taught until 1943. He contributed a classic paper on the “transmission of electromagnetic waves in hollow tubes of metal” to the PROCEEDINGS in October 1936. He and his graduate students published several more papers on waveguides, horn antennas, and cavity resonators prior to World War II. During the war, Barrow directed a radar school at MIT until he joined the Sperry Gyroscope Company as Research Director in 1943. He was appointed Vice-President in charge of research and development in 1955 and remained with Sperry until he retired in 1970. He was awarded the Edison Medal by the IEEE in 1966 in recognition of his contributions to microwave engineering. He died in New Hampshire in 1975.

James E. Brittain

School of History, Technology, and Society

Georgia Institute of Technology

Submitted by Dick Reiman, Historian

Copyright 1994 IEEE. Reprinted with permission from the IEEE publication, “Scanning the Past” which covers a reprint of an article appearing in the Proceedings of the IEEE Vol. 82, No.4, August 1994.