Posts filed under 'History of Electrical Engineering'

SCANNING THE PAST: A HISTORY OF ELECTRICAL ENGINEERING FROM THE PAST

Copyright 1997 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. 85, No. 12, July 1997.

Alien B. DuMont: A Pioneer in Electronic Instruments, Radio, and Television

Sixty-five years ago this month, the proceedings of the institute of radio engineers (IRE) included a paper by Alien B. DuMont reporting on “An Investigation of Various Electrode Structures of Cathode Ray Tubes Suitable for Television Reception” (Fig. 1). At the time, he was an independent consulting engineer with a small private laboratory (Fig. 2). During his long career as an engineer-inventor and entrepreneur, he made significant contributions to ‘instrumentation as well as to radio and television com­munication. He became known for his advocacy of flexible standards in television as being less apt to inhibit innovation than the fixed standards actually adopted in 1941.

The son of an executive with a clock company, DuMont was born in Brooklyn, NY, in 1901. As a child, he was afflicted with polio, which left him with a permanent physical handicap. He became a radio amateur at an early age and worked as a wireless operator on ships during summers while still in school. He graduated in electrical engineering from the Rensselaer Polytechnic Institute in 1924. Following graduation, he worked for about four years in a vacuum-tube manufacturing plant in Bloomfield, NJ, and received several patents related to the testing and production of radio tubes. In 1928, he joined the de Forest Radio Company in Passaic, NJ, as chief engineer, and continued to work on the design and manufacture of electronic tubes. In collaboration with L. de Forest, DuMont helped design an experimental television station using a mechanical scanning disk. In July 1931, he published a paper in Radio Engineering on practical aspects of a television system.

When the de Forest Radio Company was acquired by the Radio Corporation of America (RCA) in 1931, DuMont set up a small laboratory in the basement of his home, where he began developmental work on cathode-ray tubes for possible use in television receivers. This led to the publication of his December 1932 IRE paper, in which he discussed differences between cathode-ray tubes intended for use in television as opposed to oscilloscopes. During this period, he supplemented his income by serving as an expert witness in patent litigation and as a consultant. He was elected a Fellow of the IRE in 1931 and later became a Fellow of the American Institute of Electrical Engineers (AIEE) as well.

In 1932, DuMont invented the so-called “magic eye,” an electronic tube that proved quite useful as a visual tuning aid in radio receivers. It featured a small display that could be altered by a voltage such as that produced by an automatic-volume control circuit. He sold the rights of this invention to RCA, which developed commercial magic-eye tubes such as the 6E5. DuMont also invented a “cathautograph” or “electronic pencil,” which enabled one to write on the screen of a cathode-ray tube with a special long-persistence coating. He published a paper on this device in Electronics in January 1933.

In 1934, DuMont incorporated his laboratory as the Alien B. DuMont Laboratories and moved it into a building formerly used as a pickle factory in Passaic, NJ. There, he began to produce and market cathode-ray oscilloscopes and achieved sales of more than $100000 by 1937. Many of the instruments were acquired by engineering schools for use in teaching and research. In 1938, Paramount Pictures invested in the DuMont Labs, enabling renewed work on electronic television systems. DuMont became an outspo-

ken critic of television standards proposed by the Radio Manufacturers Association (RMA) in 1939 (Fig. 3). Instead of fixed standards, he favored “continuous flexibility” in parameters such as the scanning rate. He believed that the RMA-recommended standards would tend to stagnate engineering design and inhibit needed enhancement of picture quality. He did serve as a member of the Na­tional Television Systems Committee, which formulated the standards ultimately adopted and approved by the Federal Communication Commission in April 1941. His recommen­dations were rejected as likely to increase receiver cost and complexity of operation.

During 1941, DuMont initiated television broadcasting over station W2XWV (later WABD) in New York City. The same year, he received licenses to operate stations in Passaic, NJ, and Washington, D.C. He served as the first president of the Television Broadcasters Association in 1943. During World War II, the DuMont Labs produced instruments (Fig. 4), radar, and navigational equipment for the military services. After the war, the DuMont Television Network was formed, linking stations owned by DuMont with numerous affiliated stations. DuMont also manufac­tured television receivers until 1958, when this business

was sold to the Emerson Radio and Phonograph Company (Fig. 5). In 1960, DuMont Labs merged with the Fairchild Camera and Instrument Company, with DuMont himself becoming a senior consultant to Fairchild, He received the unusual distinction of being elected an Honorary Member of the AIEE in 1961. He died in November 1965 at age 64.

James E. Brittain

PROCEEDINGS OF THE IEEE, VOL. 85, NO. 12, DECEMBER 1997

November 19th, 2012

SCANNING THE PAST: A HISTORY OF ELECTRICAL ENGINEERING FROM THE PAST

Submitted by Marc Bell, Editor

Copyright 1997 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. 85, No. 11, November 1997.

Edward W. Herold: A Leader in the Development of Color Television

Sixty years ago this month, the proceedings of the institute of radio engineers (IRE) included a paper by Edward W. Herold (Fig. 1) on an application of negative resistance in vacuum-tube circuits. At the time, he was a research engineer at the Radio Corporation of America (RCA), where he worked for approximately 36 years. He received the IEEE Founder’s Medal in 1976 as recognition for his outstanding contributions to the electrical engineer­ing profession, including his leadership in the development of the shadow-mask picture tube for color television.

Herold was born in New York City in 1907, and devel­oped an early interest in amateur radio. He worked as a technical assistant in the Engineering Department of the Western Electric Company in 1924-1925, and at the Bell Telephone Laboratories in 1925-1926. Early in 1927, he became a vacuum-tube tester at the E. T. Cunningham Company, known for the high quality of its electronic tubes, and he continued to work there during summer vacations as an undergraduate. He received the degree in physics from the University of Virginia in 1930 and the M.S. degree from the Polytechnic Institute of Brooklyn in 1942.

Herold joined an advanced development group at the Radiotron subsidiary of RCA in July 1930, where his group was responsible for the development of new types of vacuum tubes suitable for radio applications. One of his first projects was an investigation of secondary emission in screen-grid tubes (tetrodes), and his first patent application, filed in 1932, concerned a method to suppress secondary emission (Fig. 2). This invention was utilized in the Type 48 power tetrode, and the related research was reported in his first IRE paper, published in the October 1935 proceedings, on the subject of “negative resistance and devices for obtaining it.” During the 1930’s, he also con­tributed to improvements and applications of pentode power amplifiers and the pentagrid converter tube. He also worked on wide-band amplifiers suitable for television receivers and designed and built a home television receiver in time to pick up broadcasts originating at the 1939 World’s Fair. He published a paper in 1940 in the RCA Review on converters for television receivers.

Herold joined the newly established RCA Laboratories in Princeton, NJ, in 1942. He published a comprehensive IRE paper on frequency converters and mixers in February

1942 and was coauthor with L. Malter of a series of IRE papers on radio reception at ultrahigh frequencies, published during 1943. Herold was elected a fellow of the IRE in 1948 for his contributions to the theory and design of vacuum tubes.

By 1949, it became evident to proponents of color television that a critical problem was the lack of a color picture tube suitable for compatibility with existing black-and-white television. Consequently, top management at RCA decided in September 1949 to launch a crash program involving several teams to attempt to produce a solution to the problem. Herold was given overall responsibility for organizing and directing the company-wide effort. One of the RCA researchers, H. B. Law, made a key invention involving a photolithographic technique that enabled fab­rication of the so-called shadow-mask picture tube. RCA gave a public demonstration of a prototype shadow-mask tube in March 1950 and began manufacture of the tubes in 1951.

A special theme issue of the proceedings of the IRE published in October 1951 featured 11 papers by RCA participants in the crash research program. Included were Law’s paper, “A Three-Gun Shadow-Mask Color

Kinescope,” and Herold’s paper, “Methods Suitable for Television Color Kinescopes.” In a retrospective article on the history of color television displays published in the proceedings of the IEEE in September 1976, Herold characterized the shadow-mask color tube as “one of the most dramatic and important developments of the past quarter century.” (See Figs. 3-5.)

 

 

 

 

Herold left RCA in 1959 to become a vice president of research at Varian Associates in Palo Alto, CA. He returned to RCA in 1965, where he was director of technology at the David Sarnoff Research Laboratories until his retirement in 1972. Following his retirement, he engaged in private consulting and served as chairman of the board of the Palisades Institute for Research Services. He also served as chairman of an IEEE planning committee assigned to identify areas neglected by the IEEE and served on the Editorial Board of IEEE SPECTRUM. He exhibited an avid interest in electrical engineering history and served on the IEEE History Committee for several years in the 1980’s. He died in June 1993 at age 85.

James E. Brittain


PROCEEDINGS OF THE IEEE, VOL. 85, NO. 11, NOVEMBER 1997

October 9th, 2012

Scanning the Past: A History of Electrical Engineering from the Past

Submitted by Marc Bell, Editor

Copyright 1997 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. 85, No. 9, September 1997.

Ralph Bown and the Golden Age of Propagation Research

    Sixty years ago this month, the PROCEEDINGS OF THE INSTITUTE OF RADIO ENGINEERS (IRE) included a paper by R. Bown (Fig. 1) on the development of transoceanic radiotelephony. At the time, he was director of radio research at the Bell Telephone Laboratories. Bown already had served as president of the IRE and was a future recipient of the IRE Medal of Honor. He was a leader in the collection and analysis of wave propagation data as the useful radio spectrum expanded to include shorter wavelengths after World War I.

  Bown was born in Fairport, NY, in 1891 and graduated in engineering from Cornell University in 1913. He continued his education at Cornell, where he received the master’s degree in 1915 and the Ph.D. degree in 1917. He served as a physics instructor while completing his graduate studies and was an officer in the U.S. Army Signal Corps (Fig. 2) during 1917-1919. He joined the development and research department of the American Telephone and Telegraph Company in New York City in 1919, where he worked until 1934.

  Bown and several colleagues were active participants in what has been characterized as the “golden era” of propagation investigations in the 1920’s. They used recording oscillographs and other instruments to monitor wave propagation over time and over a wide range of frequencies. They introduced multiple-unit antennas as a way to minimize fading and determined that speech-to-noise ratio was more useful than simply measuring field strengths from remote transmitters. They developed specifications for the design of transmitters and receivers to minimize cost while achieving adequate quality for commercial communication over transoceanic distances. Early findings were included in an April 1923 PROCEEDINGS paper entitled “Radio Transmission Measurements” by Bown and two coauthors, C. R. Englund and H. T. Friis (Figs. 3-5). Bown also coauthored two papers concerning radio broadcast propagation for the PROCEEDINGS of August 1924 and February 1926. Bown was elected a fellow of the IRE in 1925 and received the Morris N. Liebmann Memorial Award from the IRE in 1926 in recognition of his contributions to greater understanding of propagation phenomena. He was elected president of the IRE in 1927.

  In 1934, Bown joined the staff of Bell Telephone Laboratories, where he directed research on radio and television. He was appointed to the Microwave Committee of the National Defense Research Committee in fall 1940 and was involved in the decision to create the legendary Radiation Laboratory at the Massachusetts Institute of Technology. He insisted that research on microwave propagation be emphasized at the new laboratory. He served as a consultant to the U.S. secretary of war and helped define the mission of the Radio Research Laboratory established at Harvard University to develop electronic counter-measures equipment and techniques. A proposal that he made to enhance the performance of a navy ship borne radar against low-flying aircraft was adopted and proved successful.

 Bown became director of research at Bell Labs in 1946, a position he held until 1951. He then served as a vice president until his retirement in 1956. He authored a paper in 1955 in which he gave his personal perspective on the research effort that had led to the invention of the transistor in 1947. The IRE awarded him its prestigious Medal of Honor in 1949 as recognition for both his technical contributions and his dedicated service to the IRE. Subsequently, he received the Founders Medal from the IRE in 1961. Bown died in July 1971 at age 80.

 James E. Brittain

April 11th, 2012

Scanning the Past: A History of Electrical Engineering from the Past

Submitted by Marc Bell, Editor

Copyright 1997 IEEE. Reprinted with permission from the IEEE publication, “

 Harold S. Black and the Negative Feedback Amplifier

Scanning the Past” which covers a reprint of an article appearing in the Proceedings of the IEEE Vol. 85, No. 8, August 1997.

Seventy years ago this month, H. S. Black (Fig. 1) of Bell Telephone Laboratories conceived the negative feedback amplifier while aboard the Lackawanna Ferry on his way to work. Thirty years later, M. J. Kelly, president of the Bell Labs, characterized Black’s invention as ranking with the de Forest audion “as one of the two inventions of broadest scope and significance in electronics and communications of the past 50 years.” Kelly credited the negative feed­back amplifier with having made possible the long-distance telecommunications networks that covered the country, as well as transoceanic telephone cables. He noted that by 1957, the application of the negative feedback principle had transcended telecommunications and had stimulated “the entire explosive extension of the area of control, both electrical and mechanical.”

Black was born in Leominister, MA, in 1898 and grad­uated in electrical engineering from the Worcester Poly­technic Institute in 1921. That year, he joined the Systems Engineering Department of the Western Electric Company in New York City, which became part of Bell Laboratories in 1925. He frequently came to the office on Sundays to peruse technical reports on projects covering the past two decades. His initial assignment was to investigate distortion in vacuum-tube amplifiers used as repeaters in telephonic carrier systems. He undertook a laborious analysis of distor­tion and linearity requirements as a function of the number of channels and designed various amplifiers in a quest for circuits suitable for multichannel amplifiers used in tandem over long distances. During the 1920’s, he worked closely with Kelly, who was in charge of vacuum-tube research.

 In March 1923, Black attended an inspiring talk by C. P. Steinmetz, which, according to Black, provided a stimulus to his invention of a “feedforward amplifier.” This invention, which he patented in 1928, utilized biconjugate networks to isolate and cancel distortion. The technique proved fairly successful in laboratory tests but required frequent adjustment of the filament current and plate voltage and was too complicated to use commercially. Thus, it was in the context of a research effort extending over a number of years that Black came up with the negative feedback concept in early August 1927.

He sketched out a preliminary design, including feedback equations, on a blank page of The New York Times and had it witnessed and signed when he arrived at work (Fig. 2). By December 1927, he demonstrated a large reduction in distortion in an actual amplifier using negative feedback. Field tests were carried out in the vicinity of Morristown, NJ, during 1930-1931 using a nine-channel system with about 70 repeaters. These experiments proved highly successful and convinced even more skeptical engineers that the negative feedback amplifier was the long-sought solution to the problem of distortion in long-distance telephone networks where numerous repeaters were-needed.

 Black’s classic paper entitled “Stabilized Feed-Back Am­plifiers” appeared in Electrical Engineering, a publication of the American Institute of Electrical Engineers (AJEE), in January 1934. He pointed out in this paper that the use of negative feedback in a high-gain amplifier enabled “extraordinary improvement in Constance of amplification and freedom from nonlinearity.” He reported the Mor­ristown tests and stated that results had been “highly satisfactory and demonstrated conclusively the correctness of the theory and the practicability of its commercial application.” He cited a related contribution made by his colleague H. Nyquist, who had developed a precise criterion for the stability of feedback amplifiers. Black concluded that vacuum-tube amplifiers “normally possessing good characteristics with respect to stability and freedom from distortion are made to possess superlatively good charac­teristics by application of the feed-back principle.” Black’s patent on the negative feedback amplifier featured broad claims and included 42 pages of text, 33 pages of figures, and nine pages of claims. Although he applied for the patent in August 1928, it was not issued until December 1937. It was required reading in at least one graduate course in electronics offered in the late 1950’s.

During World War II, Black made important contributions to the theory and applications of pulse-code modulation. His book Modulation Theory was published in 1953. He was elected a fellow of the ATEE in 1941 and was awarded the Lamme Medal by the AIEE in 1957 as recognition for the invention of the negative feedback amplifier and other contributions to telecommunications engineering (Fig. 3). He also was elected a fellow of the Institute of Radio Engineers in 1948. He retired from Bell Labs in 1963 and then worked for about three years as a research scientist with the General Precision Company. In later years, he was an independent communications consultant. He was inducted into the National Inventors Hall of Fame in 1981. He did some preliminary work on an autobiography with the tentative title Before the Ferry Docked but it remained unfinished when he died in December 1983 at age 85.

James E. Brittain

March 5th, 2012

Scanning the Past: A History of Electrical Engineering from the Past

Submitted by Marc Bell, Editor

Copyright 1997 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. 85, No. 7, July 1997.

Frank J. Sprague and the Electrification of Urban Transportation

Frank J. Sprague (Fig. 1), known for his pioneering contributions to electric traction, electric elevators, and other applications of electric motors, was born 140 years ago this month. In recognition of his achievements in the field of electric power, he received the Edison Medal of the American Institute of Electrical Engineers (AIEE) in 1910. He also served as president of the AIEE during 1892-1893.

The son of the plant superintendent of a hat factory, Sprague was born in Milford, CT, and graduated from the U.S. Naval Academy in 1878, the same year that the Edison Electric Light Company was incorporated. He served for about two years on a naval ship known as the Richmond and acted as a special correspondent of the Boston Herald while General Ulysses S. Grant spent time on the ship during visits to China and Japan. Subsequently, Sprague served aboard the Lancaster, stationed in the Mediterranean, and installed an electric call bell on the ship. He managed to observe an exhibition of electric lighting systems, including that of Edison, in Paris, France in 1881.

In 1882, Ensign Sprague was granted leave to attend and report on the Crystal Palace Electrical Exhibition in London, England. He served on the awards jury for exhibits of dynamos, electric lights, and gas engines and wrote a 169-page report for the Department of the Navy. His report included a comparison of arc and incandescent lamps and predicted that “the incandescent lamp will generally take the place of the arc lamp.” He praised the Edison lighting system and wrote that Edison “without doubt, has done more than all others, and while his system is by no means yet perfect, it is unquestionably far ahead of the work of anyone else.”

Soon after he completed his report on the Crystal Palace exhibits, Sprague left the Navy to work for Edison. Sprague recognized the commercial potential of direct-current elec­tric motors and designed an exhibit featuring motors for an electrical exhibition in Philadelphia, PA, in 1884. He then left Edison to organize the Sprague Electric Railway and Motor Company, which found a growing market for small motors suitable for driving machine tools, printing presses, and household appliances. By 1889, it was reported that Sprague motors were “to be found in well nigh every city of the Union, to the aggregate of thousands of horsepower.”

In 1887, Sprague contracted to install a 12-mile electric street railway with 40 cars in the city of Richmond, VA (Fig. 2). The Richmond transit system became operational in 1888 and was widely regarded as the prototype for an industry that expanded to about 44000 miles of track by 1917. The success in Richmond led Sprague to present an AIEE paper entitled “The Solution of Municipal Rapid Transit” in June 1888. He stated in his introduction the importance of the transit issue, especially for cities such as New York, and expressed the hope that his paper might precipitate a “general discussion of the subject, not only among electrical men but the general public as well.” He included economic data on existing horse railway systems and also compared his system with cable and steam railway systems. In addition to economic advantages, he wrote that “the riding of an electrical car is far easier than that of any cable or horse car, starting and stopping more easily, and being in a large measure free from lurching and oscillation.” He continued that “there is no dust such as rises from the heels of horses. The sanitary conditions are entirely altered, and the health and comfort of the whole population is conserved. Stables with all their unsavory characteristics and the consequent depreciation of the value of adjacent real estate disappear.”

Fig. 2. A closed car on the Richmond, VA, railway. (From Frank J. Sprague, “The Solution of Municipal Rapid Transit,” A1EE Trans., vol. 5, 1888.)

Sprague continued in his role of innovator through the development of vertical urban transportation in the form of the electric elevator. He organized the Sprague Elec­tric Elevator Company in 1892 after selling his previous company to Edison General Electric in 1890. He installed several hundred elevators before selling the business to the Otis Elevator Company. His work on elevator control led him to invent a multiple-unit control suitable for trains with individually powered cars (Fig. 3). This control system was introduced on the South Side Elevated Railway in Chicago, IL, in 1897. Sprague served on a commission appointed to arrange the electrification of Grand Central Terminal in New York City during 1903-1908. He remained a strong advocate of direct-current drive for interurban service such as that used by New York Central, which began using electric locomotives in 1906. (Fig. 4) Sprague served as a member of the Naval Consulting Board during World War I. An earlier biographical sketch described him as “keen of glance, restless, and quick of thought and action.”

Fig. 3. A Manhattan Elevated Railway train was an important application of the multiple unit system of control in an urban environment. (From The New York Electrical Handbook. New York: AIEE, 1904.)

It continued that “when taking part in public discussion he is simply the despair of stenographers, and like one of his own motors, maintains the speed no matter how great the load of argument.” Sprague died in 1934 at age 77.

Fig. 4.    A view of a New York Central electric locomotive. (From The New York Electrical Handbook.    New York: AIEE, 1904.)

 

James E. Brittain

February 7th, 2012

Scanning the Past: A History of Electrical Engineering from the Past

Submitted by Marc Bell, Editor

Copyright 1997 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. 85, No. 8, August 1997.

Harold S. Black and the Negative Feedback Amplifier

Seventy years ago this month, H. S. Black (Fig. 1) of Bell Telephone Laboratories conceived the negative feedback amplifier while aboard the Lackawanna Ferry on his way to work. Thirty years later, M. J. Kelly, president of the Bell Labs, characterized Black’s invention as ranking with the de Forest audion “as one of the two inventions of broadest scope and significance in electronics and communications of the past 50 years.” Kelly credited the negative feed­back amplifier with having made possible the long-distance telecommunications networks that covered the country, as well as transoceanic telephone cables. He noted that by 1957, the application of the negative feedback principle had transcended telecommunications and had stimulated “the entire explosive extension of the area of control, both electrical and mechanical.”

Black was born in Leominister, MA, in 1898 and grad­uated in electrical engineering from the Worcester Poly­technic Institute in 1921. That year, he joined the Systems Engineering Department of the Western Electric Company in New York City, which became part of Bell Laboratories in 1925. He frequently came to the office on Sundays to peruse technical reports on projects covering the past two decades. His initial assignment was to investigate distortion in vacuum-tube amplifiers used as repeaters in telephonic carrier systems. He undertook a laborious analysis of distor­tion and linearity requirements as a function of the number of channels and designed various amplifiers in a quest for circuits suitable for multichannel amplifiers used in tandem over long distances. During the 1920’s, he worked closely with Kelly, who was in charge of vacuum-tube research.

In March 1923, Black attended an inspiring talk by C. P. Steinmetz, which, according to Black, provided a stimulus to his invention of a “feedforward amplifier.” This invention, which he patented in 1928, utilized biconjugate networks to isolate and cancel distortion. The technique proved fairly successful in laboratory tests but required frequent adjustment of the filament current and plate voltage and was too complicated to use commercially. Thus, it was in the context of a research effort extending over a number of years that Black came up with the negative feedback concept in early August 1927. He sketched out a preliminary design, including feedback equations, on a blank page of The New York Times and had it witnessed

and signed when he arrived at work (Fig. 2). By December 1927, he demonstrated a large reduction in distortion in an actual amplifier using negative feedback. Field tests were carried out in the vicinity of Morristown, NJ, during 1930-1931 using a nine-channel system with about 70 repeaters. These experiments proved highly successful and convinced even more skeptical engineers that the negative feedback amplifier was the long-sought solution to the problem of distortion in long-distance telephone networks where numerous repeaters were-needed.

Black’s classic paper entitled “Stabilized Feed-Back Am­plifiers” appeared in Electrical Engineering, a publication of the American Institute of Electrical Engineers (AJEE), in January 1934. He pointed out in this paper that the use of negative feedback in a high-gain amplifier enabled “extraordinary improvement in Constance of amplification and freedom from nonlinearity.” He reported the Mor­ristown tests and stated that results had been “highly satisfactory and demonstrated conclusively the correctness of the theory and the practicability of its commercial application.” He cited a related contribution made by his colleague H. Nyquist, who had developed a precise criterion for the stability of feedback amplifiers. Black concluded that vacuum-tube amplifiers “normally possessing good characteristics with respect to stability and freedom from distortion are made to possess superlatively good charac­teristics by application of the feed-back principle.” Black’s patent on the negative feedback amplifier featured broad claims and included 42 pages of text, 33 pages of figures, and nine pages of claims. Although he applied for the patent in August 1928, it was not issued until December 1937. It was required reading in at least one graduate course in electronics offered in the late 1950’s.During World War II, Black made important contributions to the theory and applications of pulse-code modulation. His book Modulation Theory was published in 1953. He was elected a fellow of the ATEE in 1941 and was awarded the Lamme Medal by the AIEE in 1957 as recognition for the invention of the negative feedback amplifier and other contributions to telecommunications engineering (Fig. 3). He also was elected a fellow of the Institute of Radio Engineers in 1948. He retired from Bell Labs in 1963 and then worked for about three years as a research scientist with the General Precision Company. In later years, he was an independent communications consultant. He was inducted into the National Inventors Hall of Fame in 1981. He did some preliminary work on an autobiography with the tentative title Before the Ferry Docked but it remained unfinished when he died in December 1983 at age 85.

James E. Brittain

Add comment December 15th, 2011

History of Electrical Engineering

Scanning the Past: A History of Electrical Engineering from the Past

Submitted by Marc Bell, Editor

Copyright 1997 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. 85, No. 6, June 1997.

 Edwin H. Colpitts, a communications engineer and re­search manager, was born 125 years ago this year. Remem­bered especially as the inventor of the Colpitts oscillator, he made significant contributions to both wire and radio telephony.

  Born in 1872 in New Brunswick, Canada, Colpitts grad­uated from Mount Allison College in 1893. After two years as a teacher and school principal in Newfoundland, he enrolled at Harvard University, where he studied physics and mathematics and received a Master’s degree in 1897. He remained at Harvard for two additional years while taking advanced courses and serving as a laboratory assis­tant to John Trowbridge, director of the Jefferson Physical Laboratory.

  Early in 1899, Colpitts joined the engineering staff of the American Bell Telephone Company in Boston, MA, where he began as an assistant to George A. Campbell, known for his work on loading coils and electric wave filters. Colpitts designed a variable-frequency generator for use in research on telephonic transmission and also carried out an investigation of dielectrics for capacitors. He did both theoretical and experimental work related to the proper loading of telephone circuits to minimize distortion and attenuation. Subsequently, he undertook a comprehensive series of tests intended to reduce crosstalk by the transposition of wires in contiguous circuits.

  In 1907, Colpitts was transferred to the Western Electric Company in New York City, and in 1911, he was selected to head a research group. He and his colleagues began work on applications of the vacuum tube, including a push-pull amplifier and a modulator circuit, which he designed. The Colpitts modulator enabled signals sent by wire to control a radio transmitter at a remote location. Early in 1915, Colpitts proposed an oscillator circuit using capacitive coupling (Fig. 1) as an alternative to the inductive coupling used by the oscillator invented by a colleague, Ralph Hartley. The Bell engineers demonstrated transatlantic radio telephony using a vacuum-tube transmitter during 1915.

     Colpitts served in the Signal Corps of the U.S. Army during World War I and spent some time in France as a staff officer concerned with military communication (Fig. 2). He authored a joint paper with Edward B. Craft on radio telephony published in the Transactions of the American Institute of Electrical Engineers (AIEE) in 1919. The pa­per reviewed developments over the previous five years, including military radio equipment introduced during the war (Figs. 3, 4, and 5). Colpitts and Craft wrote that “the possibility of communication by speech between any two individuals in the civilized world is one of the most desirable ends for which engineering can strive.” They compared wire and radio telephony and included some advantages and limitations of each system (Fig. 6).

  Colpitts and Otto B. Blackwell published an important paper on carrier multiplex telephony and telegraphy in the Transactions of the AIEE in 1921. They summarized work on bandpass filters and vacuum-tube electronics, which had enabled a four-channel commercial system to be placed in operation between Baltimore, MD, and Pittsburgh, PA, in 1918. They stated that the carrier method of multiplexing was “technically one of the most interesting and important of the developments which have been perfected in the art of electrical communications during the past few years.” They observed that Campbell’s band filters had been of “vital importance in the success of carrier telephone systems,” while the thermionic vacuum tube had provided a way to overcome many barriers to commercial systems. They concluded that the technique used was “fascinating” but “to. the engineer, the economics of the situation are all important, for it avails nothing if it is not possible to accomplish by the new method the same or better results than were obtainable with the old at no greater cost.”

  Colpitts was a vice-president at the Bell Telephone Labo­ratories at the time of hisretirement in 1937, but came out of retirement to work on the National Defense Research Committee on problems related to antisubmarine warfare during World War II. He died in 1949 at age 77.

James E. Brit tain

Add comment October 8th, 2011

SEPTEMBER 2011 HISTORY

Scanning the Past: A History of Electrical Engineering from the Past
Submitted by Marc Bell, Editor

Copyright 1997 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. 85, No. 5, May 1997.

Shintaro Uda and the Wave Projector

Seventy years ago this month, the proceedings OF the institute of radio engineers (IRE) included a paper by Shintaro Uda (Fig. 1), a Japanese engineer, on the radia­tion of short waves. His paper included information on a recently invented antenna, which he called a wave projector but which later became known as the Yagi-Uda antenna. During his long career as a teacher and researcher at Tohoku University in Sendai, Japan, Uda made significant contributions to communications engineering.

Uda was born in 1896 in Toyama Ken, Japan. He studied electrical engineering under H. Yagi at Tohoku University and graduated in 1924, and then joined a communications research group directed by Yagi. One of Uda’s first projects was to design a vacuum-tube oscillator that would operate at wavelengths of’around 440 cm. Experiments using the oscillator as a transmitter led to the discovery of the wave projector, Uda initially used a resonant loop antenna and observed the directive radiation it produced. He then tried placing a parasitic loop near the driven loop in an effort to obtain a more directive beam. The idea for this arrangement apparently was suggested by an earlier investigation of loops of various shapes conducted by one of his classmates as a thesis under Yagi’s direc­tion. Subsequently, Uda substituted metal rods for parasitic loops and found that the field intensity in a preferred direction increased with the number of parasitic rods. He then undertook a systematic investigation to determine the effect on antenna directivity of changes in length, spacing, and geometric arrangement of parasitic elements (Figs. 2 and 3).

                          

Yagi and Uda reported on the properties of the new antenna in a jointly authored paper entitled “Projector of the Sharpest Beam of Electric Waves” published in the Proceedings of the Imperial Academy of Japan in February 1926. Uda provided further information on the antenna in a long series of papers in the Journal of the IEE of Japan beginning in the March 1926 issue. Delegates from the United States and elsewhere learned about the wave projector and related research when Yagi and Uda presented a joint paper entitled “A New Electric Wave Projector and Radio Beacon” at the Third Pan-Pacific Science Congress held in Tokyo, Japan, in November 1926. This was soon followed by Uda’s IRE paper published in May 1927, in which he wrote that an array of parasitic director elements caused the directivity of a radiated beam to be “remarkably improved.” Prof. Yagi visited the United States in 1928 and gave a number of talks to engineering groups about work done by the Tohoku research team. He also published a paper in the proceedings OF the IRE in June 1928, in which he discussed both the wave projector and a split-anode magnetron developed by K. Okabe.

During 1929, Uda designed a regenerative shortwave receiver (Fig. 4) using a Barkhausen tube capable of reception down to about 40-cm wavelengths (Fig 5). He and his Tohoku colleagues used this receiver in con­junction with the wave projector antenna to demonstrate that communication was feasible at distances of up to 30 km at wavelengths below 1 m. Uda discussed these experiments in a second IRE paper published in June 1930 entitled “Radio-Telegraphy and Radiotelephony on Half-Meter Waves.” He went on to design a super-regenerative receiver that could be used for reception at 17 cm and reported on tests conducted at this wavelength at an IEE of Japan meeting in April 1931. The same year, he. Was awarded the doctorate degree in engineering by Tohoku University.

In 1954, Uda and Y. Mushiake jointly authored a book entitled The Yagi-Uda Antenna, which included theoretical work completed after World War II. The two men designed Yagi-Uda antennas suitable for use as television receiving antennas for the Yagi Antenna Company during the 1950’s. Uda also carried out microwave propagation research in India during 1955-1958. Other research after the war included work on millimeter traveling-wave tubes and lasers. Uda published Short Wave Projector: Historical Records of My Studies in Early Days in 1974. He died in 1976 at age 80. His mentor, Prof. Yagi, died earlier the same year at age 90.

James E. Brittain

Add comment September 5th, 2011

MAY 2011 HISTORY

Scanning the Past: A History of Electrical Engineering from the Past
Submitted by Marc Bell, Editor

Copyright 1997 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. 85, No. 4, April 1997.

 George W. Pierce:  Radio Pioneer and Educator

    George W. Pierce, one of the founding fathers of com¬munication engineering, was born 125 years ago this year. He served as president of the Institute of Radio Engineers (IRE) in 1918 and 1919, the only person to serve a two-year term in the 50-year existence of the IRE. He received the IRE Medal of Honor in 1929 in recognition of his contributions to the theory and applications of crys¬tal detectors, piezoelectric crystals, and magnetostriction devices. The award citation also mentioned his role as a leading educator and author of books in the electrical field. 

                                    img025.jpg                    img024.jpg       
    Pierce was bom in Webberville, TX. He studied under Alexander Macfarlane (known for his contributions to the theory of alternating currents) at the University of Texas, where he graduated in physics. In 1900, Pierce earned a doctorate from Harvard University for his dissertation on high-frequency electromagnetic waves. He then studied for about a year at the Boltzman Laboratory in Leipzig, Germany, before returning to Harvard where he spent the rest of his professional career.
    In one of his first researches, Pierce used a high-frequency dynamometer to measure the current distribution in a loop antenna. He verified the image theory for antennas elevated above the earth as well as over artificial grounds. He also investigated the effects of both inductance and shunt capacity tuning of receiving antennas. His wave meter (see Fig. 1) was used in wireless telegraphy applications. At resonance, a high-pitched signal was produced in the telephone receiver. After hearing reports of the good performance of carborundum radio detectors, Pierce carried out a long series of quantitative experiments on various minerals used as crystal rectifiers (Fig. 2). He was one of the first to employ the Braun cathode-ray tube indicator with a camera to obtain visual images of rectification. His findings convinced him that the thermoelectric theory was not an adequate explanation of the rectification phenomenon. He used a similar experimental setup (Fig. 3) to study electrolytic detectors and found that, in sensitivity, “the best crystal rectifiers are about equal to the electrolytic detector.” Much of his early research was reported in his classic book Principles of Wireless Telegraphy, published in 1910.

                                                                           img023.jpg
     Oscillographic apparatus and circuits for the study of Pierce became the first Director of the Cruft Laboratory at Harvard in 1914 and was elected a Fellow of the IRE in 1915. During the World War I, he was involved in investigating ultrasonic detection of submarines for the U.S. Navy. His second book, Electric Oscillators and Electric Waves, was published in 1919. He succeeded Edwin H. Hall, remembered as the discoverer of the “Hall effect,” as Rumford Professor at Harvard in 1921. Pierce also was ele’cted to membership in the National Academy of Sciences. During the 1920’s, he added piezoelectric crystals to his research agenda and invented the “Pierce oscillator,” which he patented in 1923. He also studied the magnetostriction phenomenon and received a patent on a magnetostriction oscillator in 1928. He published a technical paper on the magnetostriction oscillator in the PROCEEDINGS OF THE IRE in January 1929. In his later years, Pierce researched the sound of bats and insects and published The Song of Insects in 1948. He died in August 1956 at the age of 84.
REFERENCES
[1] G. W. Pierce, Principles of Wireless Telegraph.   New York: McGraw-Hill, 1910.
James E. Brittain

May 5th, 2011

APRIL 2011 HISTORY

Scanning the Past: A History of Electrical Engineering from the Past
Submitted by Marc Bell, Editor

Copyright 1997 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. 85, No. 3, March 1997.

Lee de Forest and the Amplifying Audion

      Seventy-five years ago this month, the INSTITUTE OF RADIO ENGINEERS (IRE) awarded its Medal of Honor to Lee de Forest as recognition for his invention of the three-electrode amplifier and his other contributions to radio. In 1946 he received the Edison Medal of the American Institute of Electrical Engineers (AIEE) and the citation mentioned the profound technical and social consequences of the grid-controlled vacuum tube which he had intro¬duced. img018.jpgKnown for having a rather flamboyant personality, de Forest (shown in Fig. 1) was both an entrepreneur and a prolific inventor who received more than 300 patents.
     De Forest was born in Council Bluffs, IA, in 1873, the son of a Congregational minister. In 1879, the family moved to Talladega, AL, where his father served as president of Talladega College. After attending a college preparatory school in Massachusetts for two years, de Forest enrolled at the Sheffield Scientific School at Yale University in 1893, where he graduated in 1896. He went on to earn a doctoral degree from Yale in 1899 with a dissertation on standing waves produced by Hertzian waves on an open-ended transmission line. His first employment after college was in the Dynamo Department of the Western Electric Company in Chicago. He experimented with wireless communication in his spare time and developed a device he called a responder as an alternative to the coherer as a detector of wireless waves. He left Western Electric in 1901 and worked as an editor for the Western Electrician and as a part-time teacher until early in 1902 when he organized the de Forest Wireless Telegraphy Company. His company gained publicity from public demonstrations of wireless communication and the award of a gold medal for the best wireless system at the 1904 World’s Fair in St. Louis. The U.S. Navy also began to purchase some of the radio apparatus manufactured by the de Forest Company.img019.jpg
     In 1906, de Forest filed a patent application on a wireless detector which he called an audion and which, in its initial form, was a two-electrode device. He presented a technical paper at an October 1906 ATEE meeting, “The Audion: A New Receiver for Wireless Telegraphy,” and commented that in all this work, a bewildering host of new and puzzling phenomena is continually encountered. He anticipated that the audion would provide “… rich fields for study to the physicist and delight to the practical man.”img020.jpg
     In January 1907 he applied for a patent on a three-electrode audion in which one electrode consisted of a control grid inside the tube. The following month he organized a new company, the De Forest Radio Telephone Company. During 1908 he staged a radio broadcast from the Eiffel Tower in Paris, France, which was received as far as 500 miles from the transmitter.
     De Forest served as president of the Society of Wireless Telegraph Engineers and became a charter member of the
IRE when it was formed in May 1912. By that time he was employed as a research engineer by the Federal Telegraph Company and his paper “Recent Developments in the Work of the Federal Telegraph Company” appeared in the first issue of the PROCEEDINGS OF THE IRE in January 1913. With the assistance of his friend, John S. Stone, de Forest approached the American Telephone and Telegraph Company (AT&T) in October 1912 about selling rights to use the audion as a telephone amplifier. The negotiations led to an initial payment of $50 000 in July 1913 and de Forest received an additional $340 000 from AT&T by March 1917. In March 1914, he published an IRE paper, “The Audion-Detector and Amplifier,” in which he reported that the audion now enjoyed widespread use. Several examples of audion circuits of this era are shown in Figs. 2-4.
  img021.jpg   In October 1916, de Forest began broadcasting music from phonograph records five nights a week using a 250 W transmitter in New York City. The music was heard as far away as Mansfield, OH, and on one occasion, a dance was held in Morristown, NJ, using music broadcast from the de Forest radio station. At the time, he predicted that radio would especially benefit rural areas by providing news as well as img022.jpgentertainment. By 1918, the de Forest company had developed an experimental radiophone transmitter for use in airplanes with its power provided by a generator driven by an air propeller (Fig. 5). During the 1920’s, de Forest worked on the development of talking motion pictures and also became interested in television. He served as president of the IRE in 1930 and, in his presidential address, called radio a young giant which had attained maturity with astonishing speed. However, he expressed dismay at excesses in radio advertising and claimed that the public was becoming nauseated by the quality of many of the present programs. He referred to television as a sleeping giant which still was in its infancy but deserved close attention as it developed. De Forest died in June 1961 at age 87.
REFERENCES
[ 1 ]  A.M. Goldsmith, Radio Telephony.    New York: Wireless Press,
1918. [2] J. Zenneck, Wireless Telegraphy.    New York: McGraw-Hill,
1915.                                                                                                                                                                                                               James E. Brittain

April 4th, 2011

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