Alan Dower Blumlein (29 June 1903 – 7 June 1942) was an
EnglishThe English are a nation and ethnic group native to England, who speak English. The English identity as a people is of early medieval origin, when they were known in Old English as the Anglecynn....
electronicsElectronics is a branch of science and technology that deals with the controlled flow of electrons. The ability to control electron flow is usually applied to information handling or device control. Electronics is distinct from electrical science and technology, which deals with the generation,...
engineerEngineers are concerned with developing economical and safe solutions to practical problems, by applying mathematics and scientific knowledge while considering technical constraints. The term is derived from the Latin root "ingenium," meaning "cleverness"...
, notable for his many inventions in
telecommunicationTelecommunication is transmission over a distance for the purpose of communication. In earlier times, this may have involved the use of smoke signals, drums, semaphore, flags or heliograph. In modern times, telecommunication typically involves the use of electronic devices such as the telephone,...
s, sound recording,
stereoStereophonic sound, commonly called stereo, is the reproduction of sound using two or more independent audio channels through a symmetrical configuration of loudspeakers in such a way as to create the impression of sound heard from various directions, as in natural hearing...
,
televisionTelevision is a widely used telecommunication medium for transmitting and receiving moving images, either monochromatic or color, usually accompanied by sound. "Television" may also refer specifically to a television set, television programming or television transmission...
and
radarRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And...
. He received 128
patentA patent is a set of exclusive rights granted by a state to an inventor or their assignee for a limited period of time in exchange for a public disclosure of an invention....
s and was considered as one of the most significant engineers and inventors of his time.
He died on 7 June 1942, aged 38, during the secret trial of an
H2S airborne radar systemH2S was a radar system used in various British bomber aircraft from 1943 to the 1990s. It was designed to identify targets on the ground for night and all-weather bombing...
, then under development during
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
when the
Halifax bomberThe Handley Page Halifax was one of the British front-line, four-engine heavy bombers of the Royal Air Force during the Second World War. A contemporary of the famous Avro Lancaster, the Halifax remained in service until the end of the war, performing a variety of duties in addition to bombing...
he was flying in crashed at
Welsh BicknorWelsh Bicknor is an area of Herefordshire, England. Despite its name, it is not currently in Wales, but was historically a detached parish of the county of Monmouthshire....
,
HerefordshireHerefordshire is a historic and ceremonial county in the West Midlands region of England. It also forms a unitary district known as the County of Herefordshire. It borders the English ceremonial counties of Shropshire to the north, Worcestershire to the east, Gloucestershire to the southeast, and...
killing all on board.
Alan Dower Blumlein was born on 29 June 1903 in
HampsteadHampstead is an area of London, England, located north-west of Charing Cross. It is located within Inner London. It is part of the London Borough of Camden. It is known for its intellectual, artistic, musical and literary associations and for the large and hilly parkland Hampstead Heath...
,
London[]London is the capital of England and the United Kingdom. It has been a major settlement for two millennia, and the history of London goes back to its founding by the Romans, when it was named Londinium. London's core, the ancient City of London, the 'square mile', retains its medieval boundaries...
to Jewish parents.
Alan Dower Blumlein (29 June 1903 – 7 June 1942) was an
EnglishThe English are a nation and ethnic group native to England, who speak English. The English identity as a people is of early medieval origin, when they were known in Old English as the Anglecynn....
electronicsElectronics is a branch of science and technology that deals with the controlled flow of electrons. The ability to control electron flow is usually applied to information handling or device control. Electronics is distinct from electrical science and technology, which deals with the generation,...
engineerEngineers are concerned with developing economical and safe solutions to practical problems, by applying mathematics and scientific knowledge while considering technical constraints. The term is derived from the Latin root "ingenium," meaning "cleverness"...
, notable for his many inventions in
telecommunicationTelecommunication is transmission over a distance for the purpose of communication. In earlier times, this may have involved the use of smoke signals, drums, semaphore, flags or heliograph. In modern times, telecommunication typically involves the use of electronic devices such as the telephone,...
s, sound recording,
stereoStereophonic sound, commonly called stereo, is the reproduction of sound using two or more independent audio channels through a symmetrical configuration of loudspeakers in such a way as to create the impression of sound heard from various directions, as in natural hearing...
,
televisionTelevision is a widely used telecommunication medium for transmitting and receiving moving images, either monochromatic or color, usually accompanied by sound. "Television" may also refer specifically to a television set, television programming or television transmission...
and
radarRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And...
. He received 128
patentA patent is a set of exclusive rights granted by a state to an inventor or their assignee for a limited period of time in exchange for a public disclosure of an invention....
s and was considered as one of the most significant engineers and inventors of his time.
He died on 7 June 1942, aged 38, during the secret trial of an
H2S airborne radar systemH2S was a radar system used in various British bomber aircraft from 1943 to the 1990s. It was designed to identify targets on the ground for night and all-weather bombing...
, then under development during
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
when the
Halifax bomberThe Handley Page Halifax was one of the British front-line, four-engine heavy bombers of the Royal Air Force during the Second World War. A contemporary of the famous Avro Lancaster, the Halifax remained in service until the end of the war, performing a variety of duties in addition to bombing...
he was flying in crashed at
Welsh BicknorWelsh Bicknor is an area of Herefordshire, England. Despite its name, it is not currently in Wales, but was historically a detached parish of the county of Monmouthshire....
,
HerefordshireHerefordshire is a historic and ceremonial county in the West Midlands region of England. It also forms a unitary district known as the County of Herefordshire. It borders the English ceremonial counties of Shropshire to the north, Worcestershire to the east, Gloucestershire to the southeast, and...
killing all on board.
Early life
Alan Dower Blumlein was born on 29 June 1903 in
HampsteadHampstead is an area of London, England, located north-west of Charing Cross. It is located within Inner London. It is part of the London Borough of Camden. It is known for its intellectual, artistic, musical and literary associations and for the large and hilly parkland Hampstead Heath...
,
London[]London is the capital of England and the United Kingdom. It has been a major settlement for two millennia, and the history of London goes back to its founding by the Romans, when it was named Londinium. London's core, the ancient City of London, the 'square mile', retains its medieval boundaries...
to Jewish parents. His future career seems to have been determined by the age of seven, when he presented his father with an invoice for repairing the doorbell, signed "Alan Blumlein, Electrical Engineer" (with "paid" scrawled in pencil). His sister claimed that he could not read proficiently until he was 12. He replied "no, but I knew a lot of quadratic equations!"
After
matriculatingMatriculation, in the broadest sense, means to be registered or added to a list, from the Latin matricula - little list. In Scottish heraldry, for instance, a matriculation is a registration of armorial bearings...
at
Highgate SchoolSir Roger Cholmeley's School at Highgate is a British independent school in Highgate, London, England. It is a member of both the Headmaster's Conference and the Eton Group. Highgate recently made the move towards co-education ending over 400 years of single sex education...
in 1921, he studied at
City and Guilds CollegeThe City and Guilds of London Institute is a United Kingdom examining and accreditation body for vocational, managerial and engineering training, offering over 500 qualifications in 28 industry areas, spanning from entry level to the equivalent of a postgraduate degree.Incorporated in 1880, the...
(part of
Imperial CollegeImperial College London is a British university in London specialising in science, engineering, medicine and business....
). He won a Governor's scholarship and joined the second year of the course. He graduated with a
First-Class HonoursThe British undergraduate degree classification system is a grading scheme for undergraduate degrees in the United Kingdom...
B.ScA Bachelor of Science is an undergraduate academic degree awarded for completed courses that generally last three to five years ....
two years later.
Telecommunications
In 1924 Blumlein started his first job at International Western Electric, a division of the
Bell LabsBell Laboratories is the research and development organization of Alcatel-Lucent and previously of the American Telephone & Telegraph Company .Bell Laboratories has had its headquarters at Murray Hill, New Jersey, and it has research and development facilities...
. The company subsequently became International Standard Electric Corporation and then, later on,
Standard Telephones and CablesStandard Telephones and Cables Ltd was a British telephone, telegraph, radio, telecommunications and related equipment R&D manufacturer. During its history STC invented and developed several groundbreaking new technologies including PCM and optical fibres.The company began life in London as...
(STC).
During his time there, he measured the
amplitudeAmplitude is the magnitude of change in the oscillating variable, with each oscillation, within an oscillating system. For instance, sound waves are oscillations in atmospheric pressure and their amplitudes are proportional to the change in pressure during one oscillation...
/
frequency responseFrequency response is the measure of any system's output spectrum in response to an input signal. In the audible range it is usually referred to in connection with electronic amplifiers, microphones and loudspeakers. Radio spectrum frequency response can refer to measurements of coaxial cables,...
of human ears, and used the results to design the first
weightingA noise weighting is a specific amplitude-vs.-frequency characteristic that is designed to allow subjectively valid measurement of noise. It emphasises the parts of the spectrum that are most important....
networks.
In 1924 he published (with Professor Edward Mallett) the first of his only two
IEEThe Institution of Electrical Engineers or IEE was a British professional organisation for electronics, electrical, manufacturing and IT professionals. In 2006 it merged with the IIE to form the Institution of Engineering and Technology...
papers, on high-frequency resistance measurement. This won him the IEE's Premium award for innovation. The following year he wrote (with Norman Kipping) a series of seven articles for
Wireless WorldWireless World was the pre-eminent British magazine for radio and electronics enthusiasts. It was one of the very few "informal" journals which were tolerated as a professional expense.- History :...
.
In 1925 and 1926, Blumlein and John Percy Johns designed an improved form of
loading coilIn electronics, a loading coil or load coil is a coil that does not provide coupling to any other circuit, but is inserted in a circuit to increase its inductance. The need was discovered by Oliver Heaviside in studying the disappointing slow speed of the Transatlantic telegraph cable...
which reduced loss and crosstalk in long-distance telephone lines. These were used until the end of the analogue telephony era. The same duo also invented an improved form of AC measurement
bridgeA Wheatstone bridge is a measuring instrument invented by Samuel Hunter Christie in 1833 and improved and popularized by Sir Charles Wheatstone in 1843. It is used to measure an unknown electrical resistance by balancing two legs of a bridge circuit, one leg of which includes the unknown component...
which became known as the
Blumlein Bridge. These two inventions were the basis for Blumlein's first two patents.
His inventions while working at STC resulted in another five patents, which were not awarded until after he left the company in 1929.
Sound recording
In 1929 Blumlein handed in his notice at STC and joined the
Columbia Graphophone CompanyThe Columbia Graphophone Company was one of the earliest gramophone companies in the United Kingdom.- Early history :In 1922, Columbia Phonograph, as it was then known, sold its UK subsidiary Columbia Graphophone. However, in 1925 Columbia Graphophone bought its former parent for $2.5 million. In...
, where he reported directly to general manager
Isaac ShoenbergSir Isaac Shoenberg was an electronic engineer born in Russia who was best known for his role in history of television....
.
His first project was to find a method of disc cutting that circumvented a Bell patent in the
Western Electric moving-iron cutting head then used, and on which substantial royalties had to be paid. He invented the moving-coil disc cutting head, which not only got around the patent but offered greatly improved sound quality. He led a small team which developed the concept into a practical cutter. The other principal team members were Herbert Holman and Henry "Ham" Clark. Their work resulted in several patents.
Early in 1931, the Columbia Graphophone Company and the
Gramophone CompanyThe Gramophone Company, based in the United Kingdom, was one of the early recording companies, and was the parent organization for the famous "His Master's Voice" label...
merged and became
EMIThe EMI Group is a British music company. It is the fourth-largest business group and family of record labels in the recording industry, making it one of the "big four" record companies. EMI Group also has a major publishing arm- EMI Music Publishing- based in New York City...
. New joint research laboratories were set up at
HayesHayes is a town in the London Borough of Hillingdon. It is a suburban development situated west of Charing Cross. Hayes was developed in the late 19th and 20th centuries as an industrial locality to which residential districts were later added to house factory workers...
and Blumlein was officially transferred there on 1 November the same year.
During the early 1930s Blumlein and Herbert Holman developed a series of moving-coil microphones, which were used in EMI recording studios and by the
BBCThe British Broadcasting Corporation, usually referred to by its abbreviation as the "BBC", is the longest established and largest broadcaster in the world...
at
Alexandra PalaceSet in Alexandra Park, Alexandra Palace was built in an area spanning Wood Green and Muswell Hill, North London, England, in 1873 as a public centre of recreation, education and entertainment and as North London's counterpart to the Crystal Palace in South London.-Overview:The Great Hall and West...
.
Stereo
Blumlein developed his ideas on what he called "binaural sound", now known as stereo, during this same period.
In early 1931, Blumlein and his wife were at a local cinema. The sound reproduction systems of the early "talkies" invariably only had a single set of speakers - which could lead to the somewhat disconcerting effect of the actor being on one side of the screen whilst his voice appeared to come from the other. Blumlein declared to his wife that he had found a way to make the sound follow the actor across the screen.
The genesis of these ideas is uncertain, but he explained them to Isaac Shoenberg in the late summer of 1931. His earliest notes on the subject are dated 25 September 1931, and his patent had the headline "Improvements in and relating to Sound-transmission, Sound-recording and Sound-reproducing Systems". The application, No. 34,657/31, was dated 14 December 1931; it was
complete left on 10 November 1932, and was
complete accepted on 14 June 1933 as British patent No. 394325.
Whereas work led by
Harvey FletcherHarvey Fletcher was an American physicist. He is credited with the invention of the hearing aid and the audiometer...
at Bell Labs at about the same time considered sound systems using multiple channels, Blumlein always aimed at a system with just two channels.
The patent covered many ideas in stereo, some of which are used today and some not. Some 70 claims include:
- A "shuffling" circuit, which aimed to preserve the directional effect when sound from a spaced pair of microphones was reproduced via a pair of loudspeakers instead of stereo headphones;
- The use of a coincident pair of velocity microphones with their axes at right angles to each other, which is still known as a "Blumlein Pair
Blumlein Pair is the name for a stereo recording technique invented by Alan Blumlein for the creation of recordings that — upon replaying through headphones or loudspeakers — recreate the spatial characteristics of the recorded signal....
";
- Recording two channels in the single groove of a record using the two groove walls at right angles to each other and 45 degrees to the vertical;
- A stereo disc-cutting head;
- Using hybrid transformers to matrix between left and right signals and sum and difference signals;
Binaural experiments began in early 1933, and the first stereo discs were cut later the same year.
Much of the development work on this system for cinematic use did not reach completion until 1935. In a few short test films (most notably, "Trains At Hayes Station" and, "The Walking & Talking Film"), Blumlein's original intent of having the sound follow the actor was fully realised.
Television
Television was developed by many individuals and companies throughout the 1920s and 1930s. Blumlein's contributions, as a member of the EMI team, started in earnest in 1933 when his boss, Isaac Shoenberg, assigned him full-time to TV research.
His ideas included:
- Resonant flyback scanning (the use of a tuned circuit in the creation of a sawtooth deflection waveform). (British Patent No. 400976, application filed April 1932.)
- Use of constant-impedance network in power supplies to obtain voltage regulation independent of load frequency, extending down to DC (421546, filed 16 June 1933).
- Black-level clamping (422914, filed 11 July 1933 by Blumlein, Browne and Hardwick). This is an improved form of DC restoration, compared to the simple DC restorer (consisting of a capacitor, diode and resistor) which had been patented by Peter Willans three months earlier.
Blumlein was also largely responsible for the development of the waveform structure used in the
405-lineThe 405-line monochrome analogue television broadcasting system was the first fully electronic television system to be used in regular broadcasting....
Marconi-EMI system - originally developed for the UK's BBC Television Service at
Alexandra PalaceSet in Alexandra Park, Alexandra Palace was built in an area spanning Wood Green and Muswell Hill, North London, England, in 1873 as a public centre of recreation, education and entertainment and as North London's counterpart to the Crystal Palace in South London.-Overview:The Great Hall and West...
, the world's first scheduled
"high definition" (240 lines or better) television service - which was later adopted as the
CCIR System A.
H2S radar and Blumlein's death
Blumlein was so central to the development of the H2S airborne radar system (to aid bomb targeting), that when he was killed on a test flight in June 1942, many believed that the project would fail. However it survived and was a factor in shortening the Second World War. Blumlein's role in the project was a closely guarded secret at the time and consequently only a brief announcement of his death was made some two years later, in order to avoid providing solace to Hitler.
His invention of the line type pulse modulator, (ref vol 5 of MIT Radiation Laboratory series) was a major contribution to high powered pulse radars, not just the H2S's system, and continues to be used today.
Personal life
Alan Blumlein had two sons, Simon Blumlein and David Blumlein, Headmaster Emeritus of a prep school in Ealing, London.
Tributes
- Alan Blumlein Way is a road on the Tektronix
Tektronix, Inc. is a North American company best known for its test and measurement equipment such as oscilloscopes, logic analyzers, and video and mobile test protocol equipment. As of November 2007, Tektronix is a subsidiary of Danaher Corporation....
Beaverton, OregonBeaverton is a city in Washington County, Oregon, United States, seven miles west of Portland in the Tualatin River Valley., its population is estimated to be 86,205, almost 14% more than the 2000 census figure of 76,129...
campus, keeping with their policy of naming roads after those who made significant contributions to the knowledge and understanding in the field of electronics.
See also
- H2S radar
H2S was a radar system used in various British bomber aircraft from 1943 to the 1990s. It was designed to identify targets on the ground for night and all-weather bombing...
- Blumlein Pair
Blumlein Pair is the name for a stereo recording technique invented by Alan Blumlein for the creation of recordings that — upon replaying through headphones or loudspeakers — recreate the spatial characteristics of the recorded signal....
, a stereo recording technique invented by Alan Blumlein.
- Stereophonic sound
Stereophonic sound, commonly called stereo, is the reproduction of sound using two or more independent audio channels through a symmetrical configuration of loudspeakers in such a way as to create the impression of sound heard from various directions, as in natural hearing...
- Blumlein transmission line, used to create high-voltage pulses with short rise and fall times.
External links