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 development of digital engineering in the years following the Second World War. At the Signals Research and Development Establishment (SRDE), his work ranged across a number of emerging engineering problems, including telemetry, binary measurement, digital communications and automatic control. These problems were not initially part of a clearly defined programme of digital engineering. Rather, they arose as engineers sought practical solutions to increasingly complex problems of measurement, communication and control, with the solution to one problem often creating another. Barker's research followed several of these problems in parallel, developing new techniques as the problems themselves evolved. The archive reveals how these apparently separate strands of research subsequently came together as important elements of digital engineering.
Many of the engineering principles that underpin today's digitally controlled world were being developed before programmable computers became commonplace. Barker's significance lies in the way his research addressed these problems in their early stages, drawing on electronics, binary systems, communications, mathematics and mechanical engineering. His work contributed to the technological foundations which later enabled computerised control systems to be built.
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, patents, 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. They show his research developing as a connected programme of digital engineering, from the conversion of analogue measurements into binary form, through digital transmission, to the control of machines.
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. His practical approach to engineering enabled him to work across these disciplines, as the problems he encountered increasingly required an understanding of measurement, electronics, communications and mechanical systems.
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-missile telemetry. He was subsequently put in charge of the telemetry for Britain's LOPGAP programme (Liquid Oxygen Propelled Guided Anti-Aircraft Programme), “responsible for devising, developing and seeing into production the first system of telemetry for guided weapons.”
Pioneering digital engineering
The IET Archives reveal that Barker's 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 using digital data. This work brought together electronics, binary systems, communications, mathematics and mechanical engineering in ways that were important to the emerging field of digital engineering.
One of the first challenges was to find practical ways of turning measurements into numbers that could be handled electronically. Just as a speedometer converts the speed of a car into a reading on a dial, Barker developed methods for converting physical measurements into numerical signals that could be represented and transmitted electronically. 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. A patent application for the device 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, representing an important step towards the automation of engineering systems. The same basic principle is now widely used in systems that need to measure the precise position or movement of mechanical components, including industrial machinery, aircraft autopilots, robots and many more.
Once physical measurements could be represented digitally, another problem arose: how could this information be transmitted and received reliably in the presence of electrical noise, increasing distance and interference? Barker's research included the study of specially designed binary signal sequences, published in 1953 and subsequently known internationally as Barker codes. These sequences of binary pulses allow a receiver to recognise a wanted signal and determine its timing, even when the signal is weak or affected by interference. This was an important practical problem in digital communications, and the solution became Barker's best-known contribution. These principles subsequently found applications in systems such as radar, ultrasound, broadband communications and many other technologies where reliable detection of signals is essential.
The archive, however, provides evidence of a less visible part of the history of digital engineering: the development of practical ways of connecting analogue measurement and control with digital information before programmable computers became widely available for engineering research. Barker's work provides a particularly clear example of this transition.
His parallel research into pulse-monitored servomechanisms focused on a fundamental problem in automatic control: how could a machine be controlled remotely when information about its behaviour was available only as measurements taken at intervals and had to be transmitted before the next control action could be made? At the time, computerised control systems were not yet available to carry out these calculations in real time. Because each control action continued to affect the machine before the next measurement was received, Barker needed a way of predicting how the system would respond to delays, disturbances and earlier control actions. He developed mathematical methods for analysing and predicting this behaviour providing a means of predicting the response of a sampled-data control system and testing those predictions experimentally.
In a November 1950 SRDE report, The Theory of Pulse Monitored Servomechanisms and their use for Prediction, Barker developed a mathematical transform-based method for analysing pulse-monitored servomechanisms and predicting their behaviour. Although the term “z-transform” was not yet in use, the method used the variable z and provided a practical mathematical means of analysing sampled-data systems. Barker subsequently incorporated these transform functions into his doctoral thesis, describing them as the first set of transforms ever to be published. His work was subsequently read and used by researchers in the developing field of sampled-data control, as computer-based control systems were beginning to emerge.
His work was not purely theoretical. In his doctoral research, Barker experimentally tested the theory using an analogue control system, measuring its response and finding good agreement with his theoretical predictions. He then applied the methods to a practical digital servo system, investigating the effects of digital encoding, transmission delay and other sources of error. The experiments are recorded in his paper A Servo System for Digital Data Transmission, published by the IEE in January 1956. They demonstrated that the transform methods provided a practical basis for designing digital servo systems capable of predicting and compensating for delays in the transmission of digital information.
Taken together, these strands of research show Barker addressing different aspects of an emerging engineering challenge: how information about a physical system could be measured, represented digitally, transmitted reliably, mathematically analysed and ultimately used to control a machine. His work demonstrates that important elements of digital control were being developed before computerised control became established, using mathematical methods together with analogue and digital electronic systems.
The principles he was investigating subsequently became part of the technological foundations on which computerised control engineering were built, in which measurements are converted into digital information, processed computationally and used to determine the next action of a machine. This approach is now fundamental to automated machinery and industrial control, and is used in applications ranging from manufacturing systems and robots to aircraft flight-control systems and other automated processes.
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
In the late 1950s his research gradually 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 eminent scientists of modern control engineering. As his research became more widely available by publication, it attracted great interest as engineers began to realise the potential of this research. The codes remain widely used for signal detection and synchronisation in radar, satellite communications, navigation, ultrasound, broadband, automotive tracking, intelligent transport and many other digital systems.
However, much of Barker's later 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, the significance and breadth of Barker's contribution to emerging digital engineering as a whole 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.
The archive brings to light a relatively poorly documented part of the history of digital engineering, showing how practical techniques for digital measurement, transmission and control were being developed before computerised control systems became established.
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.