# Ronald Hugh Barker

Ronald Hugh Barker FIEE (28 October 1915 – 7 October 2015) was an Irish physicist and pioneer in his field of digital technology. Inventor of Barker code a method for synchronising digital communication to avoid corruption of the data received.
Barker's ground breaking contributions to digital technology have had a lasting influence on the design of digital communication systems and error-correcting codes. Barker codes continue to play a vital role in modern signal processing and communication technologies, demonstrating the enduring relevance of this mid-20th-century discovery in today’s highly interconnected world. The method has been studied and researched worldwide and is commonly used in most data transmissions today. His invention continues to be a fundamental tool in various modern technologies. Examples of applications include radar, mobile phone technology, telemetry, digital speech, ultrasound imaging and testing, GPS, Wi-Fi, radio frequency identification, barcodes, tracking, stock control and vehicle guidance.

## Early life

Ronald Hugh Barker was born in Dublin in 1915, to English parents. His early education years were disrupted by his father's frequent periods of unemployment and moves between Dublin and England to find work as an artist and stained glass window designer. He was apprenticed to Hy. Jas. Salisbury a well known stained glass artist, who can be found in Kelly's directory for 1912 as an Artist in stained glass, 50 Alma Road, St Albans.
His father and family often stayed in meagre lodgings because his father's work was poorly paid and difficult to find. For much of the time, Barker (known since his childhood as Roy) lived at 17, Thomas Street, Heath and Reach with his grandfather, John Taylor and mother Linda Taylor. At age 13 Barker was interviewed by Mr Fredrick Fairbrother, the headmaster of a new school, The Cedars (now known as Cedars Upper School) in Leighton Buzzard. After sitting for an entrance examination, he was admitted to the school. His father died soon after of pneumonia in Youghal, Co. Cork, Ireland when Barker was aged 14. Despite the difficulties he excelled at school. His mother, a school teacher, assisted in his education and taught him to play the piano and church organ at the Wesleyan Chapel, Birds Hill, Heath. After passing his Matriculation exam he won a scholarship to University College Hull and earned a 1st Class Honours degree in physics at the University of London in 1938. As a result of being raised in a poor household, Roy throughout his life, preferred to construct his own gadgets, often from scrap materials using his own ingenuity. While at school Barker became interested in electronics. He built crystal radio sets and basic three vacuum tube radios using home made components such as rectifiers, transformers and loudspeakers. His first job coincided with the start of the World War 2. Scientists were declared to be a reserved occupation, which meant that he was not eligible for conscription thereby allowing him to pursue electronic research in his career.

## Early career

Barker joined Standard Telephones and Cables (STC), North Woolwich, London in 1938 to work in their thermionic valve department, designing dental X-ray tubes and equipment. After a bombing raid over Woolwich in 1941, Roy resigned from STC, as he felt that his work on X-ray tubes did not contribute to the war effort and returned to Heath and Reach where he met his future wife to be Wendy Emily Hunt who was visiting one of her brothers billeted at Stockgrove Country Park near-by.
Barker then took up a new post as a temporary experimental officer at the Signals Experimental Establishment (SEE) for the Ministry of Supply. He initially worked at Woolwich Common, but the work soon moved to a temporary location at Warnham Court, near Horsham, England. Soon afterwards the establishment was moved to a safer site at at Somerford which had been vacated by the Air Defence Research and Development Establishment to become the Signals Research and Development Establishment (SRDE) There, he assisted with the electronics design of Wireless Set No. 19, a standard wireless set used in various armoured vehicles and tanks in World War II. He also contributed to the design of portable two way radio sets for jungle use.
In summer 1943, research staff were moved to Steamer Point, Christchurch, Dorset. Barker was promoted to a Principal Scientific Officer becoming responsible for devising, developing and producing the first British telemetry system for guided weapons. In 1944 the UK guided weapons program came into being, for which Barker conducted telemetry research. Weapons testing initially occurred at Ynyslas, before a special guided weapons range was built at the Royal Aerospace Establishment (RAE) in Aberporth. The first experimental system was named LOPGAP, an acronym of Liquid Oxygen Propelled Guided Anti-aircraft Projectile. Soon after WWII had finished he was selected to report in on telemetry equipment used in development of the German A4 rocket at Peenemunde. The report was code named Messina is dated November 9th 1945.
In 1946, Barker attended the first International Telemetering Symposium at Princeton University, New Jersey when he read two papers describing his guidance system.The report states "The proceedings are an interesting account of early telemetering work. Of the 37 papers presented, three summarised telemetering work in England. Examples of nearly all possible systems of modulation and multiplexing were reported".
Barker also worked on aerial design to improve telemetry, writing two articles on the subject, one published in Wireless Engineer in November 1948. and another on Multiple reflections between two receiving antennae published by the IEE.
Barker joined the Institution of Electrical Engineers (IEE) as a corporate member in 1945. He remained a member until he died, a total period of 70 years.

## Post-war career

At the end of the war, Barker was appointed as a senior scientific officer to research speech cryptography, which involved work on early computers and digital transmission. Barker used a technique by which speech waveforms were encoded digitally – similar to contemporary methods for encoding music – and then scrambled the stream of binary digits by multiplying it by a second stream produced synchronously in a pseudorandom number generator. During his time at SRDE, Barker led a team of 12 scientists. In 1948 he published an application for a patent which converted linear and angular movement into digital data. In this paper he states: "The invention is described throughout almost the entire specification in relation to data presented in the form of the angular position of a rotatable shaft but it will be appreciated that the methods and apparatus described are equally applicable to the measurement and recording of the position of a member capable of movement in a linear manner and consequently for a member capable of any conceivable movement". It was one of the first developments towards automation and robotics. The device is widely known as an rotary encoder. The patent granted is "Improvements in or relating to apparatus for the representation of data in a binary digital form".
By 1952 his work on digital electronics had been extended to weapons controls, servo systems and communication by pulse-code modulation, for which Barker used the z-transform method for analysis, closely analogous to the Laplace transform. Z transformations produce a discrete time signal having values for only discrete points in time. The need of discrete time signals arose due to the technological advancements in digital computers. In the appendix is the first list of transforms to be published. For this work he won the Oliver Heaviside Premium award, given by the IEE for the best mathematical paper.
Barker invented the Barker code, a well known method for synchronising digital communication systems, which he described in a paper entitled "Group Synchronisation of Binary Digital Systems". The method was initially researched at the Signals Research and Development Establishment (SRDE) just after World War II, and was intended for use in radar, rocket telemetry and digital speech. In 1952, Barker found seven Barker sequences up to a length of 13 useful for correlation between the data transmitted and the data received. The Oxford Dictionary of Computer Science defines a Barker sequence as:
   a sequence of symbols (binary or *q-ary) that, when embedded in a string of randomly chosen symbols (from the same alphabet), has zero autocorrelation except in the coincidence position. Barker sequences are used to check, and if necessary to correct, the synchronization and framing of received data.
The Barker code is extensively used in digital electronics. Introduction of the code into a stream of digital data is a simple way to check the synchronisation and framing of the received data so that the data is understood correctly by the receiver. In layman terms Barker said: "A sequence of binary digits has very little meaning unless the significance of the individual digits is known." Without a code any extraneous noisy data could disrupt the data being received turning it into gobbledegook. Radar reflections and space telemetry are particularly prone to noise. The Barker code has been used in near earth space communications, such as the Galileo global navigation satellite system, the Global Positioning System, Skylab and on the Apollo missions. Barker code was also used for early deep space exploration telemetry, such as the Pioneer 10 mission. and in the Viking programme for the first landing on Mars
In April 1954, Barker was awarded a PhD by the University of London. This led to an immediate promotion to Senior Principal Scientific Officer. The following month he attended a 6-month staff course at the Joint Services Defence College, Latimer as a civilian. On completion of the course Barker took a new post as the assistant director of the Directorate of Electronics Research and Development (Air) at the Ministry of Supply headquarters, where he was responsible for the technical administration of research and development in airborne radar, navigation aids, maritime devices and air communications. In 1957 Barker returned to SRDE as Superintendent of Research.
In 1959 Barker took a job as Director of the Central Electricity Research Laboratories (CERL) in Leatherhead, where he was responsible for the day-to-day operation of the laboratories, as well as recruitment and increasing the scientific staff from 250 to 600 people. In September 1963 the IEE hosted the first London International Telemetering Conference. The programme included a visit to CERL. Some of the work being undertaken at the laboratories included "Data Transmission Experiment on Land Lines" , "Development of a System of Automatic Load Distribution on the National Grid"; and "Turbine Blade Telemetering".
On 6 March 1962 Barker was elected a Fellow of the Institute of Physics and in 1974 of the Institution of Mechanical Engineers, serving on the Automatic Control committee of the latter.
Barker was elected a Fellow of the IEE on December 1, 1966. He served on various committees of the Power Division and the Control and Automation Division, becoming Division Chairman of the latter in 1971. Between 1972 and 1974 he was a member of the IEE Council. Barker was also a member of the IEE Supply Section, Membership and Local Centres Committees, of the Science & Education Joint Board and Membership Panel B, and of Professional Groups J6,S7, C5 and C7 (he was chairman of both the control groups). He remained active as a member until his death in 2015.
Barker was named to the board of directors of the Pullin Group in 1961. While there, he assembled a team of scientists to conduct optics research. After the company was taken over by The Rank Organisation in 1964, he became unhappy with the changes the Rank Organisation made to the company's operations. He had no say in this and it soon became apparent that he would have no opportunity for any interesting research, and the future looked uninviting. In 1965, Barker wrote an article on ball bearing motors.
In 1965 Barker made his last career move, becoming deputy director of the Royal Armament Research Establishment (RARDE) at Fort Halstead, which afforded him the rank of chief experimental officer. At Fort Halstead Barker was responsible for the assessment of non-nuclear weapons systems. Barker retired in May 1979.

## Personal life

In 1943, Barker married Wendy Hunt at the Church of St Augustine in South Croydon, and they had two sons. During retirement Roy belonged to three bridge clubs, playing duplicate bridge at county level. He was still playing at his local bridge club in Verwood until his 99th birthday. Barker died in Bournemouth hospital aged 99 on 7 October 2015.