Walter Guyton Cady
Encyclopedia
Dr. Walter Guyton Cady was a noted American physicist
and electrical engineer. He was a pioneer in piezoelectricity
, and in 1921 developed the first crystal oscillator
.
Cady was born in Providence, Rhode Island
, graduated from Brown University
in 1895, and studied 1897-1900 at the University of Berlin, receiving his Ph.D. in Physics in 1900. (From 1895-1897 he was also instructor in mathematics at Brown.) He was a Magnetic Observer from 1900-1902 with the Coast and Geodetic Survey, and from 1902-1946 he was a professor of physics at Wesleyan University
, where his principal interests included electrical discharges in gases, piezoelectricity, ultrasound
, piezoelectric resonators and oscillators, and crystal devices.
Before World War I
, Cady investigated arc discharges and radio detectors, but during the war became interested in crystals as he worked with General Electric Company's Research Laboratory, Columbia University
, and the Naval Experimental Station in New London, Connecticut
, on using high-frequency sound generated by piezoelectricity to detect submarine
s. His early experiments employed Rochelle salt crystals as transducers. After noticing that a quartz crystal connected to a variable-frequency electronic oscillator would vibrate strongly at a very specific frequency, but that at other frequencies it would not vibrate at all, he had the insight to apply crystal oscillators to radio frequency applications.
In 1921 Cady designed the first circuit to control frequencies based on quartz crystal resonator, and received two fundamental patents on resonators and their applications to radio in 1923. Cady quickly realized that such circuits could be used as frequency standard
s, in 1922 published an IRE
paper on this application, and in 1923 made the first direct international comparison of frequency standards by comparing his quartz resonators with frequency standards in Italy
, France
, England
, and the United States
. Cady was president of the Institute of Radio Engineers
in 1932.
During World War II, Cady again worked on military applications of piezoelectricity, including trainers for radar
operators that used piezoelectric transducers in liquid tanks to generate realistic radar returns. He retired to Pasadena, California
, in 1951, where he was a Research Associate at Caltech. He returned to Providence in 1963. After retirement he consulted for industry and the federal government.
Cady held more than 50 patents, and was the inventor of the crystal-controlled oscillator, the highly selective narrow-band crystal filter
, one of the principal theorists of the ferroelectricity
in crystals, and a historian of the science of piezoelectric crystals. He won the 1928 IEEE Morris N. Liebmann Memorial Award
, and in 1936 was the second American to receive the Duddell Medal and Prize
of the Physical Society of London
. He received honorary degrees from Brown University in 1938, and from Wesleyan in 1958. His papers are archived at the Smithsonian Institution
and the Rhode Island Historical Society
.
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
and electrical engineer. He was a pioneer in piezoelectricity
Piezoelectricity
Piezoelectricity is the charge which accumulates in certain solid materials in response to applied mechanical stress. The word piezoelectricity means electricity resulting from pressure...
, and in 1921 developed the first crystal oscillator
Crystal oscillator
A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency...
.
Cady was born in Providence, Rhode Island
Providence, Rhode Island
Providence is the capital and most populous city of Rhode Island and was one of the first cities established in the United States. Located in Providence County, it is the third largest city in the New England region...
, graduated from Brown University
Brown University
Brown University is a private, Ivy League university located in Providence, Rhode Island, United States. Founded in 1764 prior to American independence from the British Empire as the College in the English Colony of Rhode Island and Providence Plantations early in the reign of King George III ,...
in 1895, and studied 1897-1900 at the University of Berlin, receiving his Ph.D. in Physics in 1900. (From 1895-1897 he was also instructor in mathematics at Brown.) He was a Magnetic Observer from 1900-1902 with the Coast and Geodetic Survey, and from 1902-1946 he was a professor of physics at Wesleyan University
Wesleyan University
Wesleyan University is a private liberal arts college founded in 1831 and located in Middletown, Connecticut. According to the Carnegie Foundation for the Advancement of Teaching, Wesleyan is the only Baccalaureate College in the nation that emphasizes undergraduate instruction in the arts and...
, where his principal interests included electrical discharges in gases, piezoelectricity, ultrasound
Ultrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
, piezoelectric resonators and oscillators, and crystal devices.
Before World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
, Cady investigated arc discharges and radio detectors, but during the war became interested in crystals as he worked with General Electric Company's Research Laboratory, Columbia University
Columbia University
Columbia University in the City of New York is a private, Ivy League university in Manhattan, New York City. Columbia is the oldest institution of higher learning in the state of New York, the fifth oldest in the United States, and one of the country's nine Colonial Colleges founded before the...
, and the Naval Experimental Station in New London, Connecticut
New London, Connecticut
New London is a seaport city and a port of entry on the northeast coast of the United States.It is located at the mouth of the Thames River in New London County, southeastern Connecticut....
, on using high-frequency sound generated by piezoelectricity to detect submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
s. His early experiments employed Rochelle salt crystals as transducers. After noticing that a quartz crystal connected to a variable-frequency electronic oscillator would vibrate strongly at a very specific frequency, but that at other frequencies it would not vibrate at all, he had the insight to apply crystal oscillators to radio frequency applications.
In 1921 Cady designed the first circuit to control frequencies based on quartz crystal resonator, and received two fundamental patents on resonators and their applications to radio in 1923. Cady quickly realized that such circuits could be used as frequency standard
Frequency standard
A frequency standard is a stable oscillator used for frequency calibration or reference. A frequency standard generates a fundamental frequency with a high degree of accuracy and precision. Harmonics of this fundamental frequency are used to provide reference points.Since time is the reciprocal of...
s, in 1922 published an IRE
Institute of Radio Engineers
The Institute of Radio Engineers was a professional organization which existed from 1912 until January 1, 1963, when it merged with the American Institute of Electrical Engineers to form the Institute of Electrical and Electronics Engineers .-Founding:Following several attempts to form a...
paper on this application, and in 1923 made the first direct international comparison of frequency standards by comparing his quartz resonators with frequency standards in Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
, and the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Cady was president of the Institute of Radio Engineers
Institute of Radio Engineers
The Institute of Radio Engineers was a professional organization which existed from 1912 until January 1, 1963, when it merged with the American Institute of Electrical Engineers to form the Institute of Electrical and Electronics Engineers .-Founding:Following several attempts to form a...
in 1932.
During World War II, Cady again worked on military applications of piezoelectricity, including trainers for radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
operators that used piezoelectric transducers in liquid tanks to generate realistic radar returns. He retired to Pasadena, California
Pasadena, California
Pasadena is a city in Los Angeles County, California, United States. Although famous for hosting the annual Rose Bowl football game and Tournament of Roses Parade, Pasadena is the home to many scientific and cultural institutions, including the California Institute of Technology , the Jet...
, in 1951, where he was a Research Associate at Caltech. He returned to Providence in 1963. After retirement he consulted for industry and the federal government.
Cady held more than 50 patents, and was the inventor of the crystal-controlled oscillator, the highly selective narrow-band crystal filter
Crystal filter
A crystal filter is a special form of quartz crystal used in electronics systems, in particular communications devices. It provides a very precisely defined centre frequency and very steep bandpass characteristics, that is a very high Q factor—far higher than can be obtained with conventional...
, one of the principal theorists of the ferroelectricity
Ferroelectricity
Ferroelectricity is a property of certain materials which possess a spontaneous electric polarization that can be reversed by the application of an external electric field. The term is used in analogy to ferromagnetism, in which a material exhibits a permanent magnetic moment. Ferromagnetism was...
in crystals, and a historian of the science of piezoelectric crystals. He won the 1928 IEEE Morris N. Liebmann Memorial Award
IEEE Morris N. Liebmann Memorial Award
The initially called Morris Liebmann Memorial Prize provided by the Institute of Radio Engineers , the IEEE Morris N. Liebmann Memorial Award was created in 1919 in honor of Colonel Morris N. Liebmann. It was initially given to awardees who had "made public during the recent past an important...
, and in 1936 was the second American to receive the Duddell Medal and Prize
Duddell Medal and Prize
The Duddell Medal and Prize was a prize awarded annually by the Institute of Physics in the memory of William du Bois Duddell, the inventor of the electromagnetic oscillograph. The medal was instituted by the Council of The Physical Society in 1923. Between 1961 and 1973 the prize was awarded in...
of the Physical Society of London
Physical Society of London
The Physical Society of London, England, existed from 1874 to 1921. It was a scientific society and produced the Proceedings of the Physical Society of London...
. He received honorary degrees from Brown University in 1938, and from Wesleyan in 1958. His papers are archived at the Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...
and the Rhode Island Historical Society
Rhode Island Historical Society
The Rhode Island Historical Society is a privately endowed membership organization, founded in 1822, dedicated to collecting, preserving, and sharing the history of Rhode Island...
.