Ronald N. Bracewell
Encyclopedia
Ronald Newbold Bracewell AO
(July 22, 1921 – August 12, 2007) was the Lewis M. Terman Professor of Electrical Engineering, Emeritus of the Space, Telecommunications and Radioscience Laboratory at Stanford University
.
, Australia
, in 1921, and educated at Sydney Boys High School
. He graduated from the University of Sydney
in 1941 with the B.Sc. degree in mathematics and physics, later receiving the degrees of B.E. (1943), and M.E. (1948) with first class honours, and while working in the Engineering Department became the President of the Oxometrical Society. During World War II
he designed and developed microwave radar equipment in the Radiophysics Laboratory of the Commonwealth Scientific and Industrial Research Organisation, Sydney under the direction of Joseph L. Pawsey
and Edward G. Bowen
and from 1946 to 1949 was a research student at Sidney Sussex College, Cambridge
, engaged in ionospheric
research in the Cavendish Laboratory
, where he received his Ph.D. degree in physics under J. A. Ratcliffe
.
. He then lectured in radio astronomy at the Astronomy Department of the University of California, Berkeley
from September 1954 to June 1955 at the invitation of Otto Struve
, and at Stanford University during the summer of 1955, and joined the Electrical Engineering faculty at Stanford in December 1955.
In 1974 he was appointed the first Lewis M. Terman Professor and Fellow in Electrical Engineering (1974–1979). Though he retired in 1979, he continued to be active until his death.
(1950), Fellow and life member of the Institute of Electrical and Electronic Engineers (1961), Fellow of the American Association for the Advancement of Science
(1989), and was a Fellow with other significant societies and organisations.
For experimental contributions to the study of the ionosphere by means of very low frequency waves, Dr. Bracewell received the Duddell Premium of the Institution of Electrical Engineers, London in 1952. In 1992 he was elected to foreign associate membership of the Institute of Medicine of the U.S. National Academy of Sciences
(1992), the first Australian to achieve that distinction, for fundamental contributions to medical imaging. He was one of Sydney University's three honourees when alumni awards were instituted in 1992, with a citation for brain scanning, and was the 1994 recipient of the Institute of Electrical and Electronic Engineers' Heinrich Hertz medal for pioneering work in antenna aperture synthesis
and image reconstruction as applied to radio astronomy and to computer-assisted tomography. In 1998 Dr. Bracewell was named Officer of the Order of Australia
(AO) for service to science in the fields of radio astronomy and image reconstruction.
At CSIRO Radiophysics Laboratory, work that in 1942-1945 was classified appeared in a dozen reports. Activities included design, construction, and demonstration of voice-modulation equipment for a 10 cm magnetron (July 1943), a microwave triode oscillator at 25 cm using cylindrical cavity resonators, equipment designed for microwave radar in field use (wavemeter, echo box, thermistor power meter, etc.) and microwave measurement technique. Experience with numerical computation of fields in cavities led, after the war, to a Master of Engineering degree (1948) and the definitive publication on step discontinuities in radial transmission lines (1954).
While at the Cavendish Laboratory, Cambridge (1946–1950) Bracewell worked on observation and theory of upper atmospheric ionisation, contributing to experimental technique (1948), explaining solar effects (1949), and distinguishing two layers below the E-layer (1952), work recognised by the Duddell Premium.
At Stanford Professor Bracewell constructed a microwave spectroheliograph (1961), a large and complex radio telescope which produced daily temperature maps of the sun reliably for eleven years, the duration of a solar cycle. The first radio telescope
to give output automatically in printed form, and therefore capable of worldwide dissemination by teleprinter, its daily solar weather maps received acknowledgement from NASA
for support of the first manned landing on the moon.
Many fundamental papers on restoration (1954–1962), interferometry
(1958–1974) and reconstruction (1956–1961) appeared along with instrumental and observational papers. By 1961 the radio-interferometer calibration techniques developed for the spectroheliograph
first allowed an antenna system, with 52" fan beam, to equal the angular resolution of the human eye in one observation. With this beam the components of Cygnus A
, spaced 100", were put directly in evidence without the need for repeated observations with variable spacing aperture synthesis
interferometry.
The nucleus of the extragalactic source Centaurus A
was resolved into two separate components whose right ascensions were accurately determined with a 2.3-minute fan beam at 9.1 cm. Knowing that Centaurus A was composite, Bracewell used the 6.7-minute beam of the Parkes Observatory
64 m radiotelescope at 10 cm to determine the separate declinations of the components and in so doing was the first to observe strong polarisation in an extragalactic source (1962), a discovery of fundamental significance for the structure and role of astrophysical magnetic fields. Subsequent observations made at Parkes by other observers with a 14-minute and wider beams at 21 cm and longer wavelengths, though not resolving the components, were compatible with the
dependence expected from Faraday rotation if magnetic fields were the polarising agent.
A second major radiotelescope (1971) employing advanced concepts to achieve an angular resolution of 18 seconds of arc was designed and built at Stanford and applied to both solar and galactic studies. The calibration techniques for this leading-edge resolution passed into general use in radio interferometry via the medium of alumni.
Upon the discovery of the cosmic background radiation
:
With the advent of the space age, Bracewell became interested in celestial mechanics
, made observations of the radio emission from Sputnik 1
, and supplied the press with accurate charts predicting the path of Soviet satellites, which were perfectly visible, if you knew when and where to look. Following the puzzling performance of Explorer I
in orbit, he published the first explanation (1958-9) of the observed spin instability of satellites, in terms of the Poinsot motion of a non-rigid body with internal friction. He recorded the signals from Sputniks I, II and III and discussed them in terms of the satellite spin, antenna polarisation, and propagation effects of the ionised medium, especially Faraday effect.
Later (1978, 1979) he invented a spinning, nulling
, two-element infrared interferometer suitable for space-shuttle launching into an orbit near Jupiter
, with milliarcsecond resolution, that could lead to the discovery of planets around stars other than the sun
. This concept was elaborated in 1995 by Angel and Woolf, whose space-station version with four-element double nulling became the Terrestrial Planet Finder
(TPF), NASA's candidate for imaging planetary configurations of other stars (Scientific American, April 1996).
Imaging in astronomy led to participation in development of computer assisted x-ray tomography, where commercial scanners reconstruct tomographic images using the algorithm developed by Bracewell for radioastronomical reconstruction from fan-beam scans. This corpus of work has been recognized by the Institute of Medicine, an award by the University of Sydney
, and the Heinrich Hertz medal. Service on the founding editorial board of the Journal for Computer-Assisted Tomography, to which he also contributed publications, and on the scientific advisory boards of medical instrumentation companies maintained Bracewell's interest in medical imaging, which became an important part of his regular graduate lectures on imaging, and forms an important part of his 1995 text on imaging.
Experience with the optics, mechanics and control of radiotelescopes led to involvement with solar thermophotovoltaic energy at the time of the energy crisis, including the fabrication of low-cost solid and perforated paraboloidal reflectors by hydraulic inflation.
Bracewell is also known for being the first to propose the use of autonomous interstellar space probes for of communication between alien civilisations as an alternative to radio
transmission dialogs. This hypothetical concept has been dubbed the Bracewell probe
after its inventor.
matrix leading to a fast algorithm for spectral analysis. This method, which has advantages over the fast Fourier algorithm, especially for images, is treated in The Hartley Transform
(1986), in U.S. Patent 4,646,256 (1987, now in the public domain), and in over 200 technical papers by various authors that were stimulated by the discovery. Analogue methods of creating a Hartley transform plane first with light and later with microwaves were demonstrated in the laboratory and permitted the determination of electromagnetic phase by the use of square-law detectors. A new elementary signal representation, the Chirplet transform
, was discovered (1991) that complements the Gabor elementary signal representations used in dynamic spectral analysis (with the property of meeting the bandwidth-duration minimum associated with the uncertainty principle
). This advance opened a new field of adaptive dynamic spectra with wide application in information analysis.
He was also interested in the trees of Stanford's campus and published a book about them. He also taught an undergraduate seminar titled I Dig Trees.http://trees.stanford.edu/http://news-service.stanford.edu/news/2005/march30/trees-033005.html
Bracewell was also a designer and builder of sundial
s. He built one on the South side of the Terman Engineering Building. He built one at the home of his son, Mark Bracewell. He built another on the deck of professor John Linvill's house.
As his seminar "I Dig Trees" indicated, Dr. Bracewell was known for having a tremendously keen, intelligent sense of wry, science-infused humor. One of his treasured family photos showed him sitting on the ground, legs akimbo, with a beer bottle in front of him that he had neatly balanced on one of its bottom edges—his proof that even that thin edge had 3 balance points.
Order of Australia
The Order of Australia is an order of chivalry established on 14 February 1975 by Elizabeth II, Queen of Australia, "for the purpose of according recognition to Australian citizens and other persons for achievement or for meritorious service"...
(July 22, 1921 – August 12, 2007) was the Lewis M. Terman Professor of Electrical Engineering, Emeritus of the Space, Telecommunications and Radioscience Laboratory at Stanford University
Stanford University
The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...
.
Education
Bracewell was born in SydneySydney
Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, in 1921, and educated at Sydney Boys High School
Sydney Boys High School
Sydney Boys High School is an academically selective public secondary school for boys, located in the City of Sydney, Sydney, New South Wales, Australia, with 1,180 students, from years 7 to 12...
. He graduated from the University of Sydney
University of Sydney
The University of Sydney is a public university located in Sydney, New South Wales. The main campus spreads across the suburbs of Camperdown and Darlington on the southwestern outskirts of the Sydney CBD. Founded in 1850, it is the oldest university in Australia and Oceania...
in 1941 with the B.Sc. degree in mathematics and physics, later receiving the degrees of B.E. (1943), and M.E. (1948) with first class honours, and while working in the Engineering Department became the President of the Oxometrical Society. During World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
he designed and developed microwave radar equipment in the Radiophysics Laboratory of the Commonwealth Scientific and Industrial Research Organisation, Sydney under the direction of Joseph L. Pawsey
Joseph Lade Pawsey
Joseph Lade Pawsey was an Australian engineer, radiophysicist, and radio astronomer.He was born in Ararat, Victoria to a family of farmers. At the age of 14 he was awarded a government scholarship to study at Wesley College, Melbourne, followed by a scholarship to study at the University of...
and Edward G. Bowen
Edward George Bowen
Edward George 'Taffy' Bowen, CBE, FRS was a British physicist who made a major contribution to the development of radar, and so helped win both the Battle of Britain and the Battle of the Atlantic...
and from 1946 to 1949 was a research student at Sidney Sussex College, Cambridge
Cambridge
The city of Cambridge is a university town and the administrative centre of the county of Cambridgeshire, England. It lies in East Anglia about north of London. Cambridge is at the heart of the high-technology centre known as Silicon Fen – a play on Silicon Valley and the fens surrounding the...
, engaged in ionospheric
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
research in the Cavendish Laboratory
Cavendish Laboratory
The Cavendish Laboratory is the Department of Physics at the University of Cambridge, and is part of the university's School of Physical Sciences. It was opened in 1874 as a teaching laboratory....
, where he received his Ph.D. degree in physics under J. A. Ratcliffe
J. A. Ratcliffe
John Ashworth Ratcliffe, FRS , "JAR or Jack", was an influential British radio physicist....
.
Career
From October 1949 to September 1954 Dr. Bracewell was a Senior Research Officer at the Radiophysics Laboratory of the CSIRO, Sydney, concerned with very long wave propagation and radio astronomyRadio astronomy
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of...
. He then lectured in radio astronomy at the Astronomy Department of the University of California, Berkeley
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...
from September 1954 to June 1955 at the invitation of Otto Struve
Otto Struve
Otto Struve was a Russian astronomer. In Russian, his name is sometimes given as Otto Lyudvigovich Struve ; however, he spent most of his life and his entire scientific career in the United States...
, and at Stanford University during the summer of 1955, and joined the Electrical Engineering faculty at Stanford in December 1955.
In 1974 he was appointed the first Lewis M. Terman Professor and Fellow in Electrical Engineering (1974–1979). Though he retired in 1979, he continued to be active until his death.
Contributions and Honours
Professor Bracewell was a Fellow of the Royal Astronomical SocietyRoyal Astronomical Society
The Royal Astronomical Society is a learned society that began as the Astronomical Society of London in 1820 to support astronomical research . It became the Royal Astronomical Society in 1831 on receiving its Royal Charter from William IV...
(1950), Fellow and life member of the Institute of Electrical and Electronic Engineers (1961), Fellow of the American Association for the Advancement of Science
American Association for the Advancement of Science
The American Association for the Advancement of Science is an international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsibility, and supporting scientific education and science outreach for the...
(1989), and was a Fellow with other significant societies and organisations.
For experimental contributions to the study of the ionosphere by means of very low frequency waves, Dr. Bracewell received the Duddell Premium of the Institution of Electrical Engineers, London in 1952. In 1992 he was elected to foreign associate membership of the Institute of Medicine of the U.S. National Academy of Sciences
United States National Academy of Sciences
The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...
(1992), the first Australian to achieve that distinction, for fundamental contributions to medical imaging. He was one of Sydney University's three honourees when alumni awards were instituted in 1992, with a citation for brain scanning, and was the 1994 recipient of the Institute of Electrical and Electronic Engineers' Heinrich Hertz medal for pioneering work in antenna aperture synthesis
Aperture synthesis
Aperture synthesis or synthesis imaging is a type of interferometry that mixes signals from a collection of telescopes to produce images having the same angular resolution as an instrument the size of the entire collection...
and image reconstruction as applied to radio astronomy and to computer-assisted tomography. In 1998 Dr. Bracewell was named Officer of the Order of Australia
Order of Australia
The Order of Australia is an order of chivalry established on 14 February 1975 by Elizabeth II, Queen of Australia, "for the purpose of according recognition to Australian citizens and other persons for achievement or for meritorious service"...
(AO) for service to science in the fields of radio astronomy and image reconstruction.
At CSIRO Radiophysics Laboratory, work that in 1942-1945 was classified appeared in a dozen reports. Activities included design, construction, and demonstration of voice-modulation equipment for a 10 cm magnetron (July 1943), a microwave triode oscillator at 25 cm using cylindrical cavity resonators, equipment designed for microwave radar in field use (wavemeter, echo box, thermistor power meter, etc.) and microwave measurement technique. Experience with numerical computation of fields in cavities led, after the war, to a Master of Engineering degree (1948) and the definitive publication on step discontinuities in radial transmission lines (1954).
While at the Cavendish Laboratory, Cambridge (1946–1950) Bracewell worked on observation and theory of upper atmospheric ionisation, contributing to experimental technique (1948), explaining solar effects (1949), and distinguishing two layers below the E-layer (1952), work recognised by the Duddell Premium.
At Stanford Professor Bracewell constructed a microwave spectroheliograph (1961), a large and complex radio telescope which produced daily temperature maps of the sun reliably for eleven years, the duration of a solar cycle. The first radio telescope
Radio telescope
A radio telescope is a form of directional radio antenna used in radio astronomy. The same types of antennas are also used in tracking and collecting data from satellites and space probes...
to give output automatically in printed form, and therefore capable of worldwide dissemination by teleprinter, its daily solar weather maps received acknowledgement from NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
for support of the first manned landing on the moon.
Many fundamental papers on restoration (1954–1962), interferometry
Interferometry
Interferometry refers to a family of techniques in which electromagnetic waves are superimposed in order to extract information about the waves. An instrument used to interfere waves is called an interferometer. Interferometry is an important investigative technique in the fields of astronomy,...
(1958–1974) and reconstruction (1956–1961) appeared along with instrumental and observational papers. By 1961 the radio-interferometer calibration techniques developed for the spectroheliograph
Spectroheliograph
The spectroheliograph is an instrument used in astronomy. It captures a photographic image of the Sun at a single wavelength of light, a monochromatic image...
first allowed an antenna system, with 52" fan beam, to equal the angular resolution of the human eye in one observation. With this beam the components of Cygnus A
Cygnus A
Cygnus A is one of the most famous radio galaxies, and among the strongest radio sources in the sky.It was discovered by Grote Reber in 1939. In 1951, Cygnus A, along with Cassiopeia A, and Puppis A were the first "radio stars" identified with an optical source, of these, Cygnus A became the first...
, spaced 100", were put directly in evidence without the need for repeated observations with variable spacing aperture synthesis
Aperture synthesis
Aperture synthesis or synthesis imaging is a type of interferometry that mixes signals from a collection of telescopes to produce images having the same angular resolution as an instrument the size of the entire collection...
interferometry.
The nucleus of the extragalactic source Centaurus A
Centaurus A
Centaurus A is a prominent galaxy in the constellation of Centaurus. There is considerable debate in the literature regarding the galaxy's fundamental properties such as its Hubble type and distance...
was resolved into two separate components whose right ascensions were accurately determined with a 2.3-minute fan beam at 9.1 cm. Knowing that Centaurus A was composite, Bracewell used the 6.7-minute beam of the Parkes Observatory
Parkes Observatory
The Parkes Observatory is a radio telescope observatory, 20 kilometres north of the town of Parkes, New South Wales, Australia. It was one of several radio antennas used to receive live, televised images of the Apollo 11 moon landing on 20 July 1969....
64 m radiotelescope at 10 cm to determine the separate declinations of the components and in so doing was the first to observe strong polarisation in an extragalactic source (1962), a discovery of fundamental significance for the structure and role of astrophysical magnetic fields. Subsequent observations made at Parkes by other observers with a 14-minute and wider beams at 21 cm and longer wavelengths, though not resolving the components, were compatible with the
dependence expected from Faraday rotation if magnetic fields were the polarising agent.A second major radiotelescope (1971) employing advanced concepts to achieve an angular resolution of 18 seconds of arc was designed and built at Stanford and applied to both solar and galactic studies. The calibration techniques for this leading-edge resolution passed into general use in radio interferometry via the medium of alumni.
Upon the discovery of the cosmic background radiation
Cosmic microwave background radiation
In cosmology, cosmic microwave background radiation is thermal radiation filling the observable universe almost uniformly....
:
- a remarkable observational limit of 1.7 millikelvins, with considerable theoretical significance for cosmology, was set on the anisotropy in collaboration with Ph. D. student E.K. Conklin (1967), and was not improved on for many years
- the correct theory of a relativistic observer in a blackbody enclosure (1968) was given in the first of several papers by various authors obtaining the same result
- the absolute motion of the SunSunThe Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
at 308 km/s through the cosmic background radiation was measured by Conklin in 1969, some years before independent confirmation.
With the advent of the space age, Bracewell became interested in celestial mechanics
Celestial mechanics
Celestial mechanics is the branch of astronomy that deals with the motions of celestial objects. The field applies principles of physics, historically classical mechanics, to astronomical objects such as stars and planets to produce ephemeris data. Orbital mechanics is a subfield which focuses on...
, made observations of the radio emission from Sputnik 1
Sputnik 1
Sputnik 1 ) was the first artificial satellite to be put into Earth's orbit. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957. The unanticipated announcement of Sputnik 1s success precipitated the Sputnik crisis in the United States and ignited the Space...
, and supplied the press with accurate charts predicting the path of Soviet satellites, which were perfectly visible, if you knew when and where to look. Following the puzzling performance of Explorer I
Explorer I
Explorer 1 was the first Earth satellite of the United States, launched as part of its participation in the International Geophysical Year...
in orbit, he published the first explanation (1958-9) of the observed spin instability of satellites, in terms of the Poinsot motion of a non-rigid body with internal friction. He recorded the signals from Sputniks I, II and III and discussed them in terms of the satellite spin, antenna polarisation, and propagation effects of the ionised medium, especially Faraday effect.
Later (1978, 1979) he invented a spinning, nulling
Nuller
A nuller is a tool used to block out a strong source so that fainter signals near the source can be observed. An example of a nuller is being employed on the Keck Interferometer. This causes the light from a star to destructively interfere, effectively cancelling out the star's image. The faint...
, two-element infrared interferometer suitable for space-shuttle launching into an orbit near Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
, with milliarcsecond resolution, that could lead to the discovery of planets around stars other than the sun
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
. This concept was elaborated in 1995 by Angel and Woolf, whose space-station version with four-element double nulling became the Terrestrial Planet Finder
Terrestrial Planet Finder
The Terrestrial Planet Finder was a proposed project by NASA to construct a system of telescopes for detecting extrasolar terrestrial planets. TPF was postponed several times and finally cancelled...
(TPF), NASA's candidate for imaging planetary configurations of other stars (Scientific American, April 1996).
Imaging in astronomy led to participation in development of computer assisted x-ray tomography, where commercial scanners reconstruct tomographic images using the algorithm developed by Bracewell for radioastronomical reconstruction from fan-beam scans. This corpus of work has been recognized by the Institute of Medicine, an award by the University of Sydney
University of Sydney
The University of Sydney is a public university located in Sydney, New South Wales. The main campus spreads across the suburbs of Camperdown and Darlington on the southwestern outskirts of the Sydney CBD. Founded in 1850, it is the oldest university in Australia and Oceania...
, and the Heinrich Hertz medal. Service on the founding editorial board of the Journal for Computer-Assisted Tomography, to which he also contributed publications, and on the scientific advisory boards of medical instrumentation companies maintained Bracewell's interest in medical imaging, which became an important part of his regular graduate lectures on imaging, and forms an important part of his 1995 text on imaging.
Experience with the optics, mechanics and control of radiotelescopes led to involvement with solar thermophotovoltaic energy at the time of the energy crisis, including the fabrication of low-cost solid and perforated paraboloidal reflectors by hydraulic inflation.
Bracewell is also known for being the first to propose the use of autonomous interstellar space probes for of communication between alien civilisations as an alternative to radio
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
transmission dialogs. This hypothetical concept has been dubbed the Bracewell probe
Bracewell probe
A Bracewell probe is a hypothetical concept for an autonomous interstellar space probe dispatched for the express purpose of communication with one or more alien civilizations. It was proposed by Ronald N...
after its inventor.
Work in Fourier Analysis
As a consequence of relating images to Fourier analysis, in 1983 he discovered a new factorisation of the discrete Fourier transformDiscrete Hartley transform
A discrete Hartley transform is a Fourier-related transform of discrete, periodic data similar to the discrete Fourier transform , with analogous applications in signal processing and related fields. Its main distinction from the DFT is that it transforms real inputs to real outputs, with no...
matrix leading to a fast algorithm for spectral analysis. This method, which has advantages over the fast Fourier algorithm, especially for images, is treated in The Hartley Transform
Hartley transform
In mathematics, the Hartley transform is an integral transform closely related to the Fourier transform, but which transforms real-valued functions to real-valued functions. It was proposed as an alternative to the Fourier transform by R. V. L. Hartley in 1942, and is one of many known...
(1986), in U.S. Patent 4,646,256 (1987, now in the public domain), and in over 200 technical papers by various authors that were stimulated by the discovery. Analogue methods of creating a Hartley transform plane first with light and later with microwaves were demonstrated in the laboratory and permitted the determination of electromagnetic phase by the use of square-law detectors. A new elementary signal representation, the Chirplet transform
Chirplet transform
In signal processing, the chirplet transform is an inner product of an input signal with a family of analysis primitives called chirplets.-Similarity to other transforms:...
, was discovered (1991) that complements the Gabor elementary signal representations used in dynamic spectral analysis (with the property of meeting the bandwidth-duration minimum associated with the uncertainty principle
Uncertainty principle
In quantum mechanics, the Heisenberg uncertainty principle states a fundamental limit on the accuracy with which certain pairs of physical properties of a particle, such as position and momentum, can be simultaneously known...
). This advance opened a new field of adaptive dynamic spectra with wide application in information analysis.
Other Interests
Professor Bracewell was interested in conveying an appreciation of the role of science in society to the public, in mitigating the effects of scientific illiteracy on public decision making through contact with alumni groups, and in liberal undergraduate education within the framework of the Astronomy Course Program and the Western Culture program in Values, Technology, Science and Society, in both of which he taught for some years. He gave the 1996 Bunyan Lecture on The Destiny of Man.He was also interested in the trees of Stanford's campus and published a book about them. He also taught an undergraduate seminar titled I Dig Trees.http://trees.stanford.edu/http://news-service.stanford.edu/news/2005/march30/trees-033005.html
Bracewell was also a designer and builder of sundial
Sundial
A sundial is a device that measures time by the position of the Sun. In common designs such as the horizontal sundial, the sun casts a shadow from its style onto a surface marked with lines indicating the hours of the day. The style is the time-telling edge of the gnomon, often a thin rod or a...
s. He built one on the South side of the Terman Engineering Building. He built one at the home of his son, Mark Bracewell. He built another on the deck of professor John Linvill's house.
As his seminar "I Dig Trees" indicated, Dr. Bracewell was known for having a tremendously keen, intelligent sense of wry, science-infused humor. One of his treasured family photos showed him sitting on the ground, legs akimbo, with a beer bottle in front of him that he had neatly balanced on one of its bottom edges—his proof that even that thin edge had 3 balance points.
Publications
Probably incomplete.- Bracewell, R.N. and Pawsey, J.L., Radio Astronomy (Oxford, 1955) (also translated into Russian and reprinted in China)
- Bracewell, R.N., Radio Interferometry of Discrete Sources (Proceedings of the IRE, January 1958)
- Bracewell, Ronald N., ed., Paris Symposium on Radio Astronomy, IAU Symposium no. 9 and URSI Symposium no. 1, held 30 July 1958 – 6 August 1958 (Stanford Univ. Press, Stanford, CA, 1959) (also translated into Russian)
- Professor Bracewell translated Radio Astronomy, by J.L. Steinberg and J. Lequeux, (McGraw-Hill, 1963) from French
- Bracewell, R.N., The Fourier Transform and Its Applications (McGraw-Hill, 1965, 2nd ed. 1978, revised 1986) (also translated into Japanese and Polish)
- Bracewell, R.N., Trees on the Stanford Campus (Stanford: Samizdat, 1973)
- Bracewell, R.N., The Galactic Club: Intelligent Life in Outer Space (Portable Stanford: Alumni Association, 1974) (also translated into Dutch, Japanese, and Italian)
- Bracewell, R.N., The Hartley Transform (Oxford University Press, 1986) (also translated into German and Russian)
- Bracewell, R.N., Two-Dimensional Imaging (Prentice-Hall, 1995)
- Bracewell, R.N., Fourier Analysis and Imaging (Plenum, 2004)
- Bracewell, R.N., Trees of Stanford and Environs (Stanford Historical Society, 2005)
Chapter contributions
Bracewell has contributed chapters to:- Textbook of Radar Microwave Transmission and Cavity Resonator Theory, ed. E.G. Bowen, 1946
- Advances in Astronautical Sciences Satellite Rotation, ed. H. Jacobs, 1959
- The Radio Noise Spectrum Correcting Noise Maps for Beamwidth, ed. D.H. Menzel, 1960
- Modern Physics for the Engineer Radio Astronomy, ed. L. Ridenour and W. NierenbergWilliam NierenbergWilliam Aaron Nierenberg was an American physicist who worked on the Manhattan Project and was director of the Scripps Institution of Oceanography from 1965 through 1986. He was a co-founder of the George C. Marshall Institute in 1984.- Background :Nierenberg was born on February 13, 1919, at 213 E...
, 1960 - Statistical methods in Radio Wave Propagation Antenna Tolerance Theory, ed. W.C. Hoffman, 1960
- Advances in Geophysics Satellite Studies of the Ionization in Space by Radio, ed. H.E. Landsberg, 1961 (O.K. Garriott and R.N. Bracewell)
- Handbuch der Physik Radio Astronomy Techniques, ed. S. Flugge, 1962
- Encyclopedia of Electronics Extraterrestrial Radio Noise, ed. C. Susskind, 1962
- Stars and Galaxies Radio Broadcasts from the Depths of Space, ed. T.L Page, 1962
- Radio Waves and Circuits Aerials and Data Processing, ed. S. Silver, 1963
- Light and Life in the Universe Life in the Galaxy, ed. S.T. Butler and H. Messel, 1964
- Encyclopædia Britannica Telescope, Radio, 1967
- Vistas in Science The Microwave Sky, ed. David L. Arm, 1968
- Man in Inner and Outer Space The Sun (Five Chapters), ed. H. Messel and S.T. Butler, 1968
- Image Reconstruction from Projections: Implementation and Applications Image Reconstruction in Radio Astronomy, ed. G. Hermann, 1979
- Annual Review of Astronomy and Astrophysics Computer Image Processing, ed. G. Burbidge et al., 1979
- Energy for Survival How It All Began, Man the Lazy Animal, and Energy from Sunlight, ed. H. Messel, 1979
- Life in the Universe Manifestations of Advanced Civilizations, ed. J. Billingham, 1981
- Extraterrestrials: Where Are They? Preemption of the Galaxy by the First Advanced Civilization, ed. M.H. Hart and B. Zuckerman, 1982, 1995
- Transformations in Optical Signal Processing Fourier Inversion of Deficient Data, ed. W.T. Rhodes, J.R. Fienup and B.E.A. Saleh, 1984
- The Early Years of Radio Astronomy Early Work on Imaging Theory in Radio Astronomy, ed. W.T. Sullivan, III, 1984
- Indirect Imaging Inversion of Nonplanar Visibilities, ed. J.A. Roberts, 1984
- Fourier Techniques and Applications The Life of Joseph Fourier and Fourier Techniques and Applications, ed. J.F. Price, 1985
- Yearbook of Science and Technology Wavelets, 1996
- Encyclopedia of Applied Physics Fourier and Other Mathematical Transforms 1997
- Cornelius LanczosCornelius LanczosCornelius Lanczos Löwy Kornél was a Hungarian-Jewish mathematician and physicist, who was born on February 2, 1893, and died on June 25, 1974....
—Collected Published Papers with Commentaries The Fast Fourier Transform andSmoothing Data by Analysis and by Eye ed. W.R. Davis et al., 1999