Ronald Hugh Barker 1915 - 2015
A pioneer of digital engineering and a member of the IET for more than 70 years.
Dr Ronald Hugh Barker BSc (Hons), PhD, FIET, FInstP, FIMechE, CEng
Introduction
Ronald Hugh Barker (1915–2015), known throughout his life as Roy, was a British physicist, mathematician and engineer whose research contributed to the emergence of digital engineering in the years following the Second World War. At a time when engineers were seeking new ways to measure physical quantities, transmit information reliably and control machines automatically, Barker investigated how these processes could be carried out using information represented in digital form.
Many of the engineering principles that underpin today's digitally controlled world were being developed before programmable computers became commonplace. Barker was among the engineers addressing these early challenges, developing practical techniques for digital measurement, communications and automatic control. His work brought together electronics, binary systems, communications, mathematics and mechanical engineering in ways that were fundamental to this emerging field.
Much of what is now known about the breadth of Barker's research has been reconstructed from his personal papers preserved in the IET Archives (NAEST 301), together with complementary material held by the Malvern Radar and Technology History Society (MRATHS). The IET collection includes research reports, technical papers, correspondence and other material from his working career. These records reveal a much broader body of pioneering work than is apparent from Barker's best-known invention, the Barker codes, and enable his research to be seen as a connected programme extending from telemetry and digital measurement, through digital communications, to the control of machines using digital information.
Early life and education
Born in Dublin to English parents, Barker's early education was disrupted by his father's frequent moves in search of work as a stained-glass artist. Despite these difficulties, he excelled in mathematics and science, winning the Allen Prize at Cedars School, Leighton Buzzard. He graduated with First Class Honours in Physics from University College Hull in 1938 and was awarded a PhD by the University of London in 1954 for research on pulse-code servo systems.
Barker's professional interests crossed several disciplines. His background in physics and mathematics was complemented by expertise in electrical and mechanical engineering, reflected in his later fellowships of the Institution of Electrical Engineers, the Institute of Physics and the Institution of Mechanical Engineers. This broad technical foundation was particularly suited to the research he subsequently undertook in digital control engineering.
Wartime research and telemetry
After beginning his career at Standard Telephones and Cables, Barker joined the Signals Experimental Establishment, Woolwich in 1941. Following heavy bombing during the Second World War the establishment relocated to Christchurch, where it became the Signals Research and Development Establishment (SRDE). During the Second World War he led research into frequency-modulated military communications before becoming one of Britain's leading authorities on telemetry. Following the war, he investigated German V2 missile instrumentation and, in 1946, presented papers at the First International Telemetering Conference at Princeton University, helping establish international collaboration in guided-weapons telemetry. He was subsequently put in charge of the telemetry for Britain's LOPGAP missile programme, developing the telemetry for Britain's first successful guided missile system.
Pioneering digital engineering
The IET Archives reveal that Barker's most significant achievements extended far beyond the Barker codes for which he is widely remembered. Between 1946 and the mid-1950s, he pursued a sustained programme of research into how physical information could be measured, represented, transmitted and ultimately used to control machines in digital form. This work brought together electronics, binary systems, communications, mathematics and mechanical engineering in ways that were fundamental to the emerging field of digital engineering.
One of the first challenges was to find practical ways of turning information from the physical world into numbers that could be handled electronically. Barker developed methods for converting measurements directly into binary form and investigated how such information could be transmitted using pulses. His work included the development of one of Britain's earliest optical binary shaft encoders, which converted the position of a rotating shaft into a digital number, for which a patent application is dated 23 August 1948. This provided a direct link between the movement of a machine and the digital information needed to monitor or control it, an important step towards the automation of engineering systems.
Having established ways of representing physical measurements digitally, Barker turned to the problem of communicating that information reliably. His research included the study of specially designed binary signal sequences, published in 1953 and subsequently known as Barker codes. These sequences made it possible for a receiver to recognise a wanted signal and determine its timing even when the signal was weak or affected by interference. This was an important practical problem in digital communications, and the solution became Barker's best-known contribution. The archive shows, however, that it formed part of a much wider programme of research into the reliable handling of digital information.
The next challenge was to make use of digital information to control a machine. Barker's research into pulse-code servo systems addressed situations in which measurements were made at intervals rather than continuously. This created new problems because a control system had to respond correctly to information arriving in discrete steps, while the effects of previous measurements still influenced its behaviour. In a November 1950 SRDE report, Barker defined a mathematical transform for sampled data and developed a systematic set of transform functions for analysing pulse-monitored servomechanisms. Although the term “z-transform” was not yet in use, the method used the variable z and provided a practical mathematical means of analysing delay, stability and the behaviour of sampled-data systems. Barker subsequently incorporated these transform functions into his doctoral thesis, which he described as the first set of transforms ever to be published.
This work brought together the three elements that were becoming fundamental to digital engineering: digital measurement, digital communication and digital control. Barker was not simply applying digital techniques to individual engineering problems; he was developing ways for physical systems to measure information, represent it numerically, communicate it and use it to control machines.
The significance of this work was recognised during Barker's lifetime. In 1953 he was awarded the Institution of Electrical Engineers Heaviside Premium for his work on pulse transfer functions and sampled-data control systems. His research also attracted the attention of engineers and researchers internationally. The archive also shows why much of this work remained relatively little known. It was undertaken within the Ministry of Supply's restricted research environment and recorded in technical reports, memoranda, patents and other documents rather than the open scientific literature. Its full scope was therefore not readily apparent from the published record.
Looking back on this period in 1962, Barker identified the common theme of his research as “handling information represented in a digital form.” The archive shows that this was more than a retrospective description: his work progressed from telemetry and digital measurement, through digital communications, to the mathematical analysis and practical development of sampled-data control systems. Taken together, these developments place Barker among the British engineers working at the formative stage of digital engineering, before programmable computers and microprocessors became commonplace.
Scientific leadership
By the late 1950s Barker had established a reputation for combining advanced mathematics with practical engineering, together with a broad understanding of communications, instrumentation and control systems. These qualities led to increasingly senior leadership appointments in government and industry.
In 1959 he was appointed Deputy Director of the Central Electricity Research Laboratories (CERL), Leatherhead, where he helped direct one of Britain's leading industrial research establishments. He later became Technical Director of R. B. Pullin & Co., an innovative manufacturer of scientific and electrical instruments.
His final appointment was as Deputy Director of the Royal Armament Research and Development Establishment (RARDE), Fort Halstead, where he returned to government service and continued to oversee major scientific and engineering research programmes.
Professional service
Barker's senior appointments enabled him to make an increasing contribution to the engineering profession. A Fellow of the Institution of Electrical Engineers from 1960, he served on numerous committees, including the General Purposes and Finance Committee, the Membership Committee and the Control and Automation Committee, which he chaired in 1971. He also represented the IEE on the Institution of Mechanical Engineers' Automatic Control Group.
Beyond the Institution, Barker served on the Council of the British Scientific Instrument Research Association and was an external examiner for the Universities of London and Manchester. He remained an active member of the Institution for more than seventy years.
Professional recognition
As his research became more widely known, Barker established an international professional reputation in the emerging field of digital control. His surviving correspondence shows that his work attracted the attention of researchers in Britain, the United States and the Soviet Union, and that he corresponded with several pioneers of modern control engineering. During the same period, his work on Barker codes was published, attracting great interest as engineers began to realise their potential. These remain widely used for signal detection and synchronisation in radar, satellite communications, navigation, medical ultrasound, broadband and many other digital systems.
However, much of Barker's wider research remained relatively little known outside specialist circles because it was undertaken for the Ministry of Supply during the early Cold War and documented principally in defence reports, technical memoranda and patent specifications rather than via open scientific literature. Consequently, his pioneering contributions were recognised as separate achievements in digital measurement, digital communications and sampled-data control, rather than as part of his contribution to emerging digital engineering as a whole. The significance of the complete research programme, and the breadth of Barker's contribution to it, was therefore not fully recognised at the time.
Legacy
Although Barker codes remain his best-known achievement, they represent only one part of a much broader programme of research into the measurement, transmission and control of digital information. Barker was a modest man who rarely spoke about the technical and classified work he undertook. Much of what is now known about the breadth of his research has been reconstructed from his personal papers preserved in the IET Archives (NAEST 301), together with complementary material held by the Malvern Radar and Technology History Society (MRATHS). These collections enable historians and researchers to reassess the full scope of his work, revealing how his contributions to digital measurement, digital communications and sampled-data control formed part of a wider programme of pioneering digital engineering.
Related government research reports from the Signals Research and Development Establishment are also preserved in The National Archives (AVIA 23).
Source: Ronald Hugh Barker archive papers IET Archives reference NAEST 301. The deposited records are available on request. Please contact the IET Archives.