EBU Technical Review : No. 275 (Spring 1998)

The formative years of television

This is the 22nd volume in the IEE's History of Technology series. Several volumes in the series have dealt with radio and television. The author, Professor R.W. Burns, has already contributed to the series with his two books, British Television, the formative years and Radar developments to 1945.

The present volume shows all the hallmarks of intensive research. It covers the period from 1878 to 1940. Television in 1878? Well not quite. Professor Burns commences his history at a time when the first man-made images were emerging. In Chapter 1 he even goes back to the days of the Shadow Theatre and the Magic Lantern. The most likely starting date for the development of television as we know it today was probably when the photoconductive properties of selenium were discovered at the transatlantic cable station at Valencia Island on the south-west coast of Ireland. That was in 1873. This discovery stimulated many scientists and engineers to experiment with the possibility of "sending images by electricity".

Chapter 5, entitled "Distant Vision" deals with the period between 1880 and 1920. In this present day of multimedia and interactive television, it is interesting to see a reproduction from the National Archives in Washington, showing "A 19th Century Impression of two-way Television in the year 2000 AD". This is a pen sketch of a family who are viewing a large-screen tele- vision (high definition, no doubt) with a camera, microphone and ear-piece in place, to allow two-way video and audio communication. Forecasting the future of television has been a favourite pastime down through the years.

Professor Burns refers to the play by George Bernard Shaw "Back to Methuselah" which portrays Government Ministers at different locations in the year 2170, holding a conference by means of what we now call "video- conferencing".

The book goes on to describe the pioneering work of the 1920s and early 30s which was the most important time in the development of television. The work of John Logie Baird in the UK is dealt with in some detail as is the contribution of Shoenberg and others at EMI. This part of history is, of course, already covered in the author's previous book. The most interesting new material, at least for European readers, is that which refers to the developments elsewhere in Europe, in Japan and in the United States.

A system of television, based on the Nipkow Disc, was demonstrated at the 1929 Berlin Radio Exhibition by an engineer of Hungarian origin called Mihaly. With a resolution of thirty lines, this system was generally acceptable. His images were broadcast daily from a local Berlin transmitter (on a wavelength of 475.7  m). Following his success in Germany, Mihaly sought to have his system demonstrated in Britain but, despite his best efforts, he failed to get support from either the British Post Office or the BBC.

The Olympic Games of 1940 were to have been held in Tokyo and NHK, the Japanese national broadcaster, was preparing to televise the games and to transmit the events over an area within a 12 miles radius. NHK had already set up a research laboratory and had allocated a considerable amount of money to engineer a system of "high- definition television" for the Games. The outbreak of war in Europe in 1939 put an end to the Japanese plans.

The description of developments in the United States is, by far, the most interesting part of the book. Much of the material, at least as far as this reviewer is concerned, is based on recent research. Of course the work of the well-known television engineers of the day is well chronicled. The outstanding one was Dr V.K. Zworykin whose iconoscope camera tube created the fundamental element in the electronic television chain. The book deals at length with the work carried in the laboratories of Westinghouse and the Radio Corporation of America.

Of particular interest is the amount of coverage given to the work of Dr E.F.W. Alexanderson. Dr Alexanderson (a relative of the EBU Radio Director, Thomas Alexanderson) is better known as the inventor of the alternators used by Marconi in his radio telegraph transmitters in the early part of the century. Ernst Alexanderson was a Swedish engineer who emigrated to the United States as a young man. An employee of the General Electric Company, he became a key figure in the development of the high-frequency alternators used in wireless transmitters. His developments led to the formation of the Radio Corporation of America (RCA) where he served as Chief Engineer for many years. He started his work on television in 1924 and was an advocate of large-screen projection.

This book of some 660 pages represents an important contribution to the history of broadcasting and should be essential reading for those interested in the origins of our profession. It can proudly take its place beside the other 21 IEE volumes which record the history of technology.

Television: An international history of the formative years
IEE History of Technology Series, No. 22
R.W. Burns
Hardbound volume of 661 pages
The IEE in association with the Science Musem, London, 1998
Ref: ISBN 0 85296 914 7. Price: £75.00.

George T. Waters

Stereophonic sound recording – theory and practice

Readers of this excellent book should be aware of the potentially misleading title of the English edition. The term "sound recording" can be used in different contexts and, in this case, readers should not expect a book that gives technical details of recording formats.

The scope of the book is well defined in Chapter 2 as the:

• operation during which the microphone modulation and sound quality is adjusted in order to be transmitted or recorded.
  
  
• set of procedures, the aim of which is to create spatial sound perception through the picking up of sound sources and the use of electro- acoustic equipment.

The book is an operational guide to the techniques used in sound production for recording or broadcasting. It covers the various techniques used to capture and process the sound, and the treatment of the subject is very practical and down to earth. Both authors have considerable experience in the broadcasting and recording industries. They have not aimed to dictate solutions, rather to explain the reason for the variety of methods suggested and to let the reader decide how he or she can exploit them in their daily work. There is very little mathematics in the book but the authors do not avoid the use of theoretical explanations where this is necessary to understand the techniques they describe.

They are concerned essentially with live sound, i.e. actual performances taking place in real spaces, rather than heavily-processed material. After a brief non-technical review of the history of recording, they deal with the basic concepts of the profession, both technical and operational. After sections on sound and acoustics, and the preparation of recording sessions, they move on to the central theme of the book which is microphone techniques. These are explained with the help of many clear diagrams.

The book also contains useful glossaries, and a section which cross references the often confusing and over- lapping titles, functions and training of the personnel in different countries, different industries and the different branches of these industries.

For both students and practitioners, this book is a comprehensive introduction to its subject and should remain a valid reference work to the "art and mystery" of sound capture.

Stereophonic Sound Recording: Theory and Practice
Hugonnet and Walder
Hardbound volume of 291 pages
John Wiley and Sons, Chichester, UK,1998
Ref: ISBN 0-471-97487-0. Price: £29.95.

Richard Chalmers

Digital audio and video

This book provides a wide range of background information for the student, or the broadcast practitioner, in the technology of current television and radio broadcasting systems. The ground it covers includes systems for both programme production and programme delivery. Good summaries are given of current analogue television systems, as a launchpad into digital technologies.

Chapters in the book describe basic digitalization concepts, video fundamentals, audio fundamentals, audio-video production systems, analogue-to-digital conversion, video cameras, digital transmission (including some practical aspects of digital receivers), digital signal processing, data compression, video displays, digital recording, post production and digital multimedia. The book also reviews, in summary form, the new delivery issues such as the World Wide Web and video-on-demand. A glossary of terms is also included.

Although the book does not enter into detail in many areas, it does nevertheless provide a useful and relatively clear introduction to the current world of broadcast technology. To some extent, it has been written from a US point-of-view but, in spite of this, it should still be of interest to readers in other parts of the world.

Principles of Digital Audio and Video
A.C. Luther
Hardbound volume of 405 pages
Artech House, London, 1997
Ref: ISBN 0-89006-892-5. Price: £60.00.

David Wood

ATM

This comprehensive book in German has been written by two experts from Siemens, Germany. It comprises 11 chapters and two appendices, and contains 173 illustrations. All 259 literature references are detailed at the end of the book.

Chapter 1 puts ATM, which is the basis of Broadband-ISDN, into the context of past and future international developments for digital telecommunication infrastructures. Chapter 2 describes the basic concepts of ATM technology, while Chapters 3 and 4 deal with the system architecture and the protocol layers in quite some detail.

Distribution and statical multiplexing are covered in Chapter 5, while the following four chapters deal with ATM network concepts and routeing, applications, service concepts and network structures. ATM connections are described in Chapter 10.

Chapter 11 explains fundamental principles and protocols; these represent knowledge that is necessary to understand the previous chapters. The two appendices provide a comprehensive listing of the ATM standards and specifications of a number of specialized agencies and also of the ATM Forum (founded in 1991 and still in existence). Included here are those specifications that were still in the drafting stage at the time of writing. There is also a list of abbreviations used in the book.

The book is well written and aims to provide high-level multimedia telecommunication managers in the computer and switched network industries with sufficient technical detail for self- study. Relatively little technical knowledge is needed to start reading this most useful book.

ATM - Infrastruktur für die Hochleistungs-kommunikation
E. Rathged and E. Wallmeier
Hardbound volume of 535 pages
Springer, Berlin, 1997
Ref: ISBN 3-540-60370-0. Price: DM 178.

Dietmar Kopitz

Non-linear video buyers guide

It seems like only yesterday that we reviewed the Non-linear Video Buyers Guide from Sypha. It was, of course last year, and now there is a 4th edition, dated April 1998.

The new 4th edition gives details of over 500 non-linear editors, hybrid editors, disk recorders and video servers. On-line and off-line editing systems, of various quality and cost, are included: complete systems, plug-in cards for computers, and software packages. Seperate sections deal with random- access disk recorders and servers. The technical information provided covers target usage, hardware and software specifications and requirements, operational features, EDL/data management and files, and support for networking and import/export of media files. Also covered are future development plans, typical configurations, costs and details of suppliers. As in the previous edition, there is advice on assessing storage requirements, together with useful vocabularies and explanations of specialist terms.

In this rapidly developing field, even a yearly guide may seem too infrequent but the compilers of this guide have made a valiant attempt to persuade manufacturers to give advanced notice of their new products.

The Non-linear Video Buyers Guide
Edited by Y. Hashmin
Bound volume of 104 pages
Sypha Publications, London, 1998
Ref: ISBN 1-901950-00-X. Price: £22.50.

Richard Chalmers

Assessment of sound programme material

"Listening" is an integral part of all sound and television programme- making operations. The human ear alone is able to judge the aesthetic or artistic quality of programme material and, indeed, certain aspects of the technical quality. However, to permit the ear to make fair and unbiased judgements, it must be allowed to function under favourable conditions.

The listening conditions specified in this second edition of EBU document Tech. 3276 are essentially relevant in the following two situations:

• Reference listening rooms: listening rooms used for the critical assessment and selection of programme material for inclusion in a sound or television broadcaster's programme output.
  


• High-quality sound control rooms: sound control rooms used for the critical assessment of sound quality as a part of the sound or television broadcast production process.

The accuracy and quality of listening conditions depend on the relevant sound-field parameters that affect the ears of the listener. Their definition will pose a number of design constraints upon the characteristics of the loudspeakers used for monitoring, and the properties of the listening room. It may be noted that, in the case of headphone listening, the properties of the room have practically no influence on the listening conditions.

The main part of the document sets out the basic requirements for the sound-field parameters. Four Appendices then give recommendations on ways in which these requirements can be met.

To a greater or lesser extent, the listening conditions given here may inspire the implementation of listening facilities in other contexts – such as programme fairs, the assessment of programmes in competitions and the subjective testing of the technical quality of sound systems.

EBU - Listening conditions for the assessment of sound programme material:
monophonic and two-channel stereophonic (2nd edition)
EBU document Tech. 3276
EBU, Geneva, 1998
Price: 70 Swiss francs.

European Broadcasting Union Case postale 45 Ancienne Route 17A CH-1218 Grand-Saconnex Geneva Switzerland techreview@ebu.ch