Alec Reeves
was one the 20th Century's greatest, but least conventional, scientists. A brilliant engineer, his work made the 'digital age' possible. A pacifist, he altered the course - and perhaps the outcome - of World War 2. Open-minded, he experimented with the paranormal and believed he was in regular contact with the 19th century inventor of electrical generation,
Reeves was born on 10 March 1902 in Redhill, Surrey. His father Edward was Surveyor to the Royal Geographical Society. Edward Reeves had met Livingstone, Stanley and Gordon of Khartoum - and used his mapping skills in an effort to resolve the bitter battle between American explorers Robert Peary and Frederick Cook who both claimed they were the first to reach the NorMichael Faraday.th Pole.
Alec studied engineering at Imperial College, London and in 1923 joined International Western Electric, a leading manufacturer of radio and telecommunications equipment. In 1925, the firm was taken over by Sosthenes Behn's International Telephone and Telegraph in Reeves went to work at ITT's laboratory in Paris, LMT. Here he worked with brilliant engineers like Maurice Deloraine and Henri Busignies (who later developed the „HF/DF – 'Huff Duff'” – system for detecting enemy submarines). Reeves and his colleagues built the first radio–telephone links across the English Channel and the Atlantic. Reeves also perfected the condenser microphone and made major advances in the use of single sideband transmission for short-wave radio.
Reeves appears to have had an enjoyable time in Paris. He later claimed he had played in the French Open tennis championships - which were indeed 'open' to anyone who wished to participate. He is also reported to have been seen on the roof of the LMT building conducting paranormal experiments – though one report said he was 'measuring moon-beams'.
It was in Paris that Reeves had the idea that made him famous - and which helped shape the modern world. Since Alexander Graham Bell invented the telephone in 1876, speech had been turned into a continuously-varying wave of electric energy. But 'analogue' systems have a big weakness: they amplify noise and errors as well as the original message. Reeves proposed a radical alternative. Instead of sending Bell's 'voice–shaped current', he proposed that the sound be sampled at regular intervals. The values of these samples would be represented by binary numbers and transmitted as unequivocal on-off pulses.
In principle, this was a return to the simple, robust technique used by the telegraph. Sending recognisable speech, however, meant networks would have to carry millions of pulses a second. And though Reeves' extraordinary patent of 1937 showed how this might be done in theory, the valve-based technology of the time was not up to the job. Pulse Code Modulation could not be implement economically until the invention of the transistor decades later. But economy was not always a priority. PCM was first used by Bell Labs for the complex and cumbersome radio system on which Churchill and Roosevelt talked in total secrecy for much of World War 2.
Reeves fled escaped just in time when the Germans invaded France - reaching England on a coal boat but losing most of his possessions on the way. He soon entered the world of Scientific Intelligence, joining the team led by Robert Watson-Watt and A P Rowe that was secretly developing radar.
A committed pacifist, he accepted the need to defeat Hitler - a task to which he contributed decisively. For in 1941, Britain faced a crisis. German bombs had reduced cities to rubble. But the invaders had been repelled and the RAF launched its own night bombing campaign against the factories that made the enemy's weapons and raw materials.
It was a disaster: British airmen had neither the experience or equipment to navigate 'blind' and bombs fell miles from their target. Defeat looked certain.
Asked to address the night navigation problem, Reeves proposed a novel solution. A pilot would reach his target by flying in an arc centred a base station, called the 'Cat', and drop his bombs when he reached a precise distance from a second station - the 'Mouse'. An audible tone told him if he was deviating from the correct track and when someone said it sounded like an Oboe, the name stuck.
„OBOE” was so precise that a bomb dropped from 30,000 feet could land within 50 yards of its target. It was an amazing success. In March 1943, OBOE-guided planes destroyed the mighty Krupps Works at Essen which made most of Hitler's steel and guns. On the eve of D-Day, OBOE destroyed nine of ten heavy guns that could have decimated the invading force. The RAF used OBOE in over 9,000 raids. Reeves' invention - the world's first remote-controlled bombing device - had altered the course, and perhaps the outcome, of the World War 2. Nothing as accurate as this would exist until the days of the satellite and the laser.
In 1945 Reeves returned to ITT, working at Standard Telecommunications Laboratories on ways to increase the capacity and reliability of communications systems. He was a pioneer of semiconductor devices and among the first to exploit the possibility of using light to carry information. When 'waveguides' - pipes carrying high frequency signals - failed to work, Reeves thought of glass fibres. In the late 1960's, he inspired and led the team under Charles Kao and George Hockham that created the world's first practical optical fibre system.
Alec Reeves was a visionary who in the 1950s predicted that by the end of the 20th Century people would work from home, linked by optical fibre and receiving information over a screen. He was awarded over 100 patents, as well as a CBE.
But he had a less conventional side. He was deeply interested in the capacity and character of the human brain and, like earlier scientists such as Oliver Lodge (who demonstrated 'wireless' communication before Marconi) and J. J. Thomson (who discovered the electron), Reeves explored the paranormal. For most of his life, he conducted ever more complex experiments to measure the power of thought and to 'communicate' with the dead. He believed he was guided by the great Michael Faraday, who had died in 1876.
Alec Reeves - who died on 13 October 1971 - can fairly be called 'Father' of the Information Age. Pulse Code Modulation is the basis for all modern digital communications and media, the main motor for change in the 21st century and perhaps the key technology of the future. Without PCM, there would be no Internet, no digital radio or television, no digital land-line or mobile telephones, no CDs, DVDs or CD-ROMs. The idea of sending information in any form, anywhere at any time would still be the stuff of science fiction.
Alec Reeves (1902-1971) invented pulse-code modulation (PCM) in 1937 when he worked for the International Telephone and Telegraph Company. This is a very early invention in the history of electronics, since it is only a few years after Edwin Armstrong invented wideband FM, a method of high-quality radio broadcasting. Reeves, instead of following tradition by sending an electrical current being proportional with the sound level, proposed that the electrical sound signal be sampled and digitised at regular intervals. Then the analogue value of each sample would be rounded to the nearest integer value, which, in turn, is represented by a binary number and transmitted as binary on-off pulses. In principle, the binary, two-level, signalling was a return to the simple, robust technique used by the telegraph. Noise immunity and fidelity benefit tremendously because the sound signal is no longer stored as a delicate analogue signal but as a much more robust sequence of binary numbers. Because PCM is a method of representing an analogue signal in digital form, it is particularly well adapted to work directly with digital data-processing equipment.
In his 1937 patent, Reeves formulated the major advantages of digital PCM transmission, namely
Quality depends on conversion steps ONLY
Quality independent of transmission media
Compatibility with different media and traffic (video, audio, and data)
Low cost
New features can easily be embedded.
These are gigantic and also visionary conclusions. Reeves showed his enormous engineering foresight, as there are two essential assumptions that are implicit in the above characteristics. Firstly, each quantized sample can be transmitted with arbitrarily small probability of error. It was absolutely not clear in 1937 that this could be accomplished in theory; let alone that he, or others, knew about practical methods for achieving error-free transmission. There was no research on the topic of error correcting codes. It would take another ten years and a world war, before research on error free digital communication would take off. Secondly, he assumed that conversion from the analog to the digital domain, and vice versa, could be done, either in theory or practice, with arbitrary small accuracy by use of sufficiently frequent sampling, and by quantizing each sample with a sufficiently large number of levels. Early theoretical work by mathematicians had been published, but it appears that Reeves was unaware of that literature.
A notable disadvantage of PCM is the required high (analogue) bandwidth of the transmission or storage system. And though Reeves' extraordinary patent of 1937 showed how this might be done in theory, the valve-based technology of the time was not up to the job. Pulse Code Modulation could not be implement economically until the invention of the transistor decades later. But economy was not always a priority. PCM was first used by the armed forces for the SIGSALY scrambled radio system on which Churchill and Roosevelt talked in total secrecy for much of World War II.
Curing the war he also invented a 'blind bombing' system, called Oboe, which assisted in increasing the accuracy of Allied bombing raids.
Reeves also conducted paranormal research, where he employed Geiger counters, pendulums, and electronics. He claimed that his discoveries were 'guided' by Michael Faraday himself, who died in 1867.
He was awarded over 100 patents, as well as a CBE.
