Alec Reeves
Encyclopedia
Alec Harley Reeves, CBE
(March 10, 1902 - October 13, 1971) was a British
scientist best known for his invention of pulse-code modulation
(PCM). He was awarded 82 patents.
in 1902 and was educated at the Reigate Grammar School
, followed by a scholarship to the City and Guilds Engineering College in 1918, and then postgraduate studies at Imperial College London
in 1921.
in 1923, and was part of a team of engineers responsible for the first commercial transatlantic telephone link. In 1925 Western Electric's European operations were acquired by ITT
, and in 1927 Reeves was transferred to ITT's research laboratories in Paris
. Whilst in Paris, he was responsible for a number of projects, including: a short-wave radio link between the telephone network
s of Spain
and South America
, the world's first single-sideband radio telephone system, and developed a multi-channel carrier system for UHF
radio telephones. He was also responsible for innovations in the design of automatic frequency control
circuits, digital delay lines and condenser microphones.
had for reducing noise when speech is transmitted over long distances. With an analogue signal, every time the signal is amplified, the noise contained in the signal is also amplified and new, additional noise is added. With pulse code modulation, all that is required is to regenerate the pulses, hence the noise content of the signal is not increased. Reeves patented the invention in 1938. Unfortunately his idea required quite complex circuitry (by 1930s standards), that was not cost-effective, using Valves. Pulse code modulation was not used commercially until the 1950s, when the invention of the transistor
made it viable, although it was used by Bell Telephone Laboratories during the Second World War for secure communications links, such as the one between Roosevelt
and Churchill
.
by Germany
in 1940, Reeves escaped over the Spanish
border and then made his way back to England aboard a cargo ship. He joined the Royal Aircraft Establishment
at Farnborough
and took part in the development of countermeasures against the German radio navigation systems, the so called 'battle of the beams
'. Reeves was later transferred to the Telecommunications Research Establishment
as part of a team of scientist
s and engineer
s developing Britain's own radio navigation
aids. The first system they developed was called 'GEE
', a system that performed well, but was susceptible to jamming and was not accurate enough for blind bombing of targets at night or through thick cloud. Together with Frank Jones
of the Telecommunications Research Establishment
, Reeves developed a new system called 'Oboe
', which offered pin-point accuracy to within 50 yds (45m), and was resistant to jamming. 'Oboe' was to prove invaluable to the Royal Air Force
, during Bomber Command
's offensive against Germany.
and George Hockham
at Standard Telecommunication Laboratories
- initially at Enfield, North London, and later at Harlow Essex - which invented optical fibres as a means of communicating large quantities of information. Kao has recently (2010) been awarded the Nobel Prize his his part in this achievement. Reeves worked at STL until retirement. He was awarded the Stuart Ballantine Medal in 1965. and also the CBE.
Order of the British Empire
The Most Excellent Order of the British Empire is an order of chivalry established on 4 June 1917 by George V of the United Kingdom. The Order comprises five classes in civil and military divisions...
(March 10, 1902 - October 13, 1971) was a British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
scientist best known for his invention of pulse-code modulation
Pulse-code modulation
Pulse-code modulation is a method used to digitally represent sampled analog signals. It is the standard form for digital audio in computers and various Blu-ray, Compact Disc and DVD formats, as well as other uses such as digital telephone systems...
(PCM). He was awarded 82 patents.
Early life
Alec Reeves was born in Redhill, SurreyRedhill, Surrey
Redhill is a town in the borough of Reigate and Banstead, Surrey, England and is part of the London commuter belt. Redhill and the adjacent town of Reigate form a single urban area.-History:...
in 1902 and was educated at the Reigate Grammar School
Reigate Grammar School
Reigate Grammar School is an independent co-educational day school located in the town of Reigate, Surrey, United Kingdom. Intake is from 11 to 18, with the majority of its pupils entering at the age of 11, and others entering at 13 and 16.- History :...
, followed by a scholarship to the City and Guilds Engineering College in 1918, and then postgraduate studies at Imperial College London
Imperial College London
Imperial College London is a public research university located in London, United Kingdom, specialising in science, engineering, business and medicine...
in 1921.
Career
Reeves joined the International Western Electric CompanyWestern Electric
Western Electric Company was an American electrical engineering company, the manufacturing arm of AT&T from 1881 to 1995. It was the scene of a number of technological innovations and also some seminal developments in industrial management...
in 1923, and was part of a team of engineers responsible for the first commercial transatlantic telephone link. In 1925 Western Electric's European operations were acquired by ITT
ITT Corporation
ITT Corporation is a global diversified manufacturing company based in the United States. ITT participates in global markets including water and fluids management, defense and security, and motion and flow control...
, and in 1927 Reeves was transferred to ITT's research laboratories in Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
. Whilst in Paris, he was responsible for a number of projects, including: a short-wave radio link between the telephone network
Telephone network
A telephone network is a telecommunications network used for telephone calls between two or more parties.There are a number of different types of telephone network:...
s of Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, the world's first single-sideband radio telephone system, and developed a multi-channel carrier system for UHF
Ultra high frequency
Ultra-High Frequency designates the ITU Radio frequency range of electromagnetic waves between 300 MHz and 3 GHz , also known as the decimetre band or decimetre wave as the wavelengths range from one to ten decimetres...
radio telephones. He was also responsible for innovations in the design of automatic frequency control
Automatic frequency control
In radio equipment, Automatic Frequency Control is a method to automatically keep a resonant circuit tuned to the frequency of an incoming radio signal...
circuits, digital delay lines and condenser microphones.
Pulse Code Modulation
Reeves recognised the potential that pulse-code modulationPulse-code modulation
Pulse-code modulation is a method used to digitally represent sampled analog signals. It is the standard form for digital audio in computers and various Blu-ray, Compact Disc and DVD formats, as well as other uses such as digital telephone systems...
had for reducing noise when speech is transmitted over long distances. With an analogue signal, every time the signal is amplified, the noise contained in the signal is also amplified and new, additional noise is added. With pulse code modulation, all that is required is to regenerate the pulses, hence the noise content of the signal is not increased. Reeves patented the invention in 1938. Unfortunately his idea required quite complex circuitry (by 1930s standards), that was not cost-effective, using Valves. Pulse code modulation was not used commercially until the 1950s, when the invention of the transistor
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...
made it viable, although it was used by Bell Telephone Laboratories during the Second World War for secure communications links, such as the one between Roosevelt
Franklin D. Roosevelt
Franklin Delano Roosevelt , also known by his initials, FDR, was the 32nd President of the United States and a central figure in world events during the mid-20th century, leading the United States during a time of worldwide economic crisis and world war...
and Churchill
Winston Churchill
Sir Winston Leonard Spencer-Churchill, was a predominantly Conservative British politician and statesman known for his leadership of the United Kingdom during the Second World War. He is widely regarded as one of the greatest wartime leaders of the century and served as Prime Minister twice...
.
World War II
Following the invasion of FranceFrance
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...
by Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
in 1940, Reeves escaped over the Spanish
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
border and then made his way back to England aboard a cargo ship. He joined the Royal Aircraft Establishment
Royal Aircraft Establishment
The Royal Aircraft Establishment , was a British research establishment, known by several different names during its history, that eventually came under the aegis of the UK Ministry of Defence , before finally losing its identity in mergers with other institutions.The first site was at Farnborough...
at Farnborough
Farnborough, Hampshire
-History:Name changes: Ferneberga ; Farnburghe, Farenberg ; Farnborowe, Fremborough, Fameborough .Tower Hill, Cove: There is substantial evidence...
and took part in the development of countermeasures against the German radio navigation systems, the so called 'battle of the beams
Battle of the beams
The Battle of the Beams was a period early in the Second World War when bombers of the German Air Force used a number of increasingly accurate systems of radio navigation for night bombing. British "scientific intelligence" at the Air Ministry fought back with a variety of increasingly effective...
'. Reeves was later transferred to the Telecommunications Research Establishment
Telecommunications Research Establishment
The Telecommunications Research Establishment was the main United Kingdom research and development organization for radio navigation, radar, infra-red detection for heat seeking missiles, and related work for the Royal Air Force during World War II and the years that followed. The name was...
as part of a team of scientist
Scientist
A scientist in a broad sense is one engaging in a systematic activity to acquire knowledge. In a more restricted sense, a scientist is an individual who uses the scientific method. The person may be an expert in one or more areas of science. This article focuses on the more restricted use of the word...
s and engineer
Engineer
An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics and ingenuity to develop solutions for technical problems. Engineers design materials, structures, machines and systems while considering the limitations imposed by practicality,...
s developing Britain's own radio navigation
Radio navigation
Radio navigation or radionavigation is the application of radio frequencies to determine a position on the Earth. Like radiolocation, it is a type of radiodetermination.The basic principles are measurements from/to electric beacons, especially...
aids. The first system they developed was called 'GEE
GEE (navigation)
Gee was the code name given to a radio navigation system used by the Royal Air Force during World War II.Different sources record the name as GEE or Gee. The naming supposedly comes from "Grid", so the lower case form is more correct, and is the form used in Drippy's publications. See Drippy 1946....
', a system that performed well, but was susceptible to jamming and was not accurate enough for blind bombing of targets at night or through thick cloud. Together with Frank Jones
Francis Jones (physicist)
Francis "Frank" Edgar Jones, FRS, MBE was a British physicist who co-developed the OBOE blind bombing system.He was born in Wolverhampton, the son of a teacher...
of the Telecommunications Research Establishment
Telecommunications Research Establishment
The Telecommunications Research Establishment was the main United Kingdom research and development organization for radio navigation, radar, infra-red detection for heat seeking missiles, and related work for the Royal Air Force during World War II and the years that followed. The name was...
, Reeves developed a new system called 'Oboe
Oboe (navigation)
Oboe was a British aerial blind bombing targeting system in World War II, based on radio transponder technology. Oboe accurately measured the distance to an aircraft, and gave the pilot guidance on whether or not they were flying along a pre-selected circular route. The route was only 35 yards...
', which offered pin-point accuracy to within 50 yds (45m), and was resistant to jamming. 'Oboe' was to prove invaluable to the Royal Air Force
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...
, during Bomber Command
RAF Bomber Command
RAF Bomber Command controlled the RAF's bomber forces from 1936 to 1968. During World War II the command destroyed a significant proportion of Nazi Germany's industries and many German cities, and in the 1960s stood at the peak of its postwar military power with the V bombers and a supplemental...
's offensive against Germany.
Post War
After the war, Alec Reeves managed a team led by Charles K. KaoCharles K. Kao
The Honorable Sir Charles Kuen Kao, GBM, KBE, FRS, FREng is a pioneer in the development and use of fiber optics in telecommunications...
and George Hockham
George Hockham
George Alfred Hockham is an engineer who has worked for over 40 years in theoretical analysis and design techniques applied to the solution of electromagnetic problems covering many different antenna types for radar, electronic warfare and communication systems...
at Standard Telecommunication Laboratories
Standard Telecommunication Laboratories
Standard Telecommunication Laboratories was the UK Research Laboratories for the Standard Telephones and Cables Company .Initially based in Enfield, North London, and moved to Harlow Essex in 1959. At this time STC was part of ITT....
- initially at Enfield, North London, and later at Harlow Essex - which invented optical fibres as a means of communicating large quantities of information. Kao has recently (2010) been awarded the Nobel Prize his his part in this achievement. Reeves worked at STL until retirement. He was awarded the Stuart Ballantine Medal in 1965. and also the CBE.
External links
- http://www.alecharleyreeves.com contains many of Reeves' technical papers, with commentary and general biographical details, including his predictions of future trends.