Table of contents

The random response from hot-wire anemometers with a mean-square spectral output proportional to recently reported by Saddoughi and Veeravalli (1996 Meas. Sci. Technol. 7 1297 - 300) has been noted previously. A discussion is given of the relevant results.

A novel technique is described for testing searchlights and other highly collimated luminaires. The proposed method, which uses a modified detector assembly to compute the luminance at all positions in a measurement plane close to the luminaire and for all beam angles, does not require a long test range or complicated calibration techniques and therefore reduces significantly the time needed for testing. Computer simulations are presented which demonstrate the failure of the inverse square law inside the beam cross over distance when measuring the intensity on a standard screen, the validity of the proposed method within the beam cross over distance and the effects of a smoothing technique which is used to reduce noise. Results are also presented for a searchlight that has been tested with an experimental implementation of the method and these show good agreement with predicted data.

An intercomparison of cryogenic radiometers of HUT/VTT (Finland), PTB (Germany) and SP (Sweden) using silicon trap detectors was performed. Also results of monitoring of the responsivities of trap detectors over a 6 year period are presented. It was noticed that several non-idealities can undermine the agreement between results of calibrations. The non-uniformity of the responsivity of trap detectors made the results sensitive to alignment and beam size. The nonlinearity of some trap detectors was found to be large. The average relative differences in the results of the laboratories, when all known corrections are applied, are for HUT-PTB, for SP-PTB and for SP-HUT, with standard uncertainties of and , respectively.

A monitoring system using the collection technique of electrostatic precipitation on to a piezoelectric sensing element is examined. The transduction mechanism is the change in the resonant frequency of the sensing element from its unloaded nominal value of 9 MHz caused by the collected dust. The monitor had the three main design areas (point-to-plane distance, precipitator voltage and electrode-to-dust-inlet distance) optimized at a flow rate of approximately . This led to collection efficiencies greater than 97% with crystal mass sensitivity constants in the range for the aerosol Arizona Road Dust. The total sampling time is limited by overloading of the sensing element by dust. A method of extending the sampling time by using compressed air to clean the sensing element is described.

A sensor system for the measurement of air quality is presented and evaluated. It is based on the approach of mimicking the advantages of human olfactory sensing, using gas sensor measurements and fuzzy sensor fusion. Signals from four sensitive metal - oxide - semiconductor field-effect transistors (MOSFET), each with a unique selectivity profile, are used. Each sensor exhibits information which is extracted by signal analysis and used to determine a crisp air-quality profile. The resulting crisp profile is unique, representing a distinct air quality and serves as a basis for the determining of a fuzzy quality profile. A fuzzy measurement profile is then matched pair-wise to the different fuzzy quality profiles. The matches are processed with help of a fuzzy fusion technique to determine the most representative crisp air-quality profile. Preliminary experiments show that the performance of the proposed fuzzy sensor clustering system is very promising. Environmental air-quality tests inside and outside a car driving in different cities during different seasons resulted in an artificial system determining air-quality opinions. The sensor opinions are classified with reference to three air-quality references (clean, medium and polluted air) and appear to be in accordance with human opinions obtained simultaneously.

The effect of the quantization of the fringe intensity on the phase error for the general N-bucket algorithm of phase-shifting measurement is formulated. An expression for the statistical relationship between the measured phase error and the fringe intensity error is presented. The expansion of the intensity quantization error in Fourier series allows one to obtain an analytical expression for the variance of the phase given by a general N-bucket algorithm. A numerical simulation was performed and its result is in good agreement with the analytical one. Several factors influencing the quantization effects are discussed.

A system for the measurement of ultrasound velocity in liquids was automated to cope with variations in temperature and pressure . The following problems had to be solved: supervision and monitoring of the achievement of the required pressure and temperature, creation and reception of the signal, acquisition of the measurement points, identification of the signal received on the basis of the characteristics of a reference signal, measurement of ultrasound travel times, memorization and processing of the results. The system enables substantial savings of time compared with manual methods. The system calibration procedure is also described. Measurements of octane and pentane (which had been studied previously) are used to verify the validity of the system developed and to determine its degree of accuracy (absolute average deviation from literature data 0.1% and maximum deviation from literature data 0.25%).

The basic principles of an adaptive filter implemented in discrete space are discussed, and an algorithm for a two-stage cascade adaptive filter using the least-mean-squares method is given. The filter was employed to process digitised low-frequency ultrasonic signals propagated through concrete, obtained under a variety of transducer/sample coupling conditions. Very significant levels of signal recovery were possible with waveforms initially exhibiting poor signal-to-noise ratios arising from high levels of amplifier gain.

A novel design of a single-phase item of equipment, capable of providing satisfactory relative permeability data at low relative equilibrium pressures, is presented. Following certain experimental procedure, the complications of the two-phase flow and that of the macroscopic inhomogeneity have been reduced. Thus it becomes easier to utilize the powerful relative permeability technique for the characterization of porous solids.

The cut-off frequency, or frequency range, of a dynamically optimized constant temperature hot-wire anemometer is well known in terms of time constants of the wire and of the feedback amplifier, within the framework of a linear control theory of third order. A more convenient interpretation, in terms of a characteristic frequency of the wire and in terms of gain - bandwidths products of the amplifier, is presented both for an amplifier with a second-order response and for an amplifier with a first-order response. These convenient and intuitively appealing interpretations are also extended to hot-film anemometers.

This paper describes an apparatus which is able to perform tensile true constant stress or strain rate, stress-relaxation and creep tests on a thin strip specimen up to a maximum load of 20 N, in vacuum or in an inert atmosphere and at high temperature. The machine applies the load on the specimen by means of a balance beam, whose counterweight is partially submerged in a container filled with oil. The load, strain and temperature are measured with a load cell, a linear variable differential transformer and two thermocouples, respectively, and they are monitored by a personal computer through an analogue - digital interface. The computer-based control and data acquisition software was written in QBasic language and it works on the power stage through the digital outputs. The power stage consists of two pumps that change the fluid level in the container. The temperature on the specimen is achieved by using an electrical furnace controlled by a PID controller. The performance of the machine is illustrated with results on aluminium 3003 foil alloy and amorphous alloys.

In electron beam ion sources (EBIS/T) cathodes with high current densities are of great interest. Commonly used cathodes like impregnated tungsten cathodes and cathodes emit current densities of 10 and 100 A , respectively. In order to obtain high electron beam current densities of for the stepwise ionization of few-electron, high-Z ions [] or for the fast production of low-Z bare nuclei, the electron beam compression has to be very high using these cathodes. A high beam compression increases the beam temperature, which limits the current density. High current densities are also limited by the magnetic flux through the cathode. The application of small highly emissive cathodes, like Ir - Ce cathodes, reduces the magnetic flux through the cathode, so that a magnetic shield of the emitter is no longer required. By emitting relatively high currents from these small cathodes, hence emitting high emission current densities, the desired beam current densities can be attained by a moderate beam compression.

We have constructed a low cost isostatic press for operation at 150 MPa (1500 bar) that can also perform considerable work on the volume of the sample. It consists of two stainless steel cylinders filled with water. Pressure is created by cooling the water below C using the fact that when ice forms the pressure rises since the solid phase has a larger volume than the liquid phase. Using this press we have fabricated rods of 60% theoretical density.

This paper presents results for a tomographic system using an array of electrodynamic sensors. Sensitivity maps are derived for the individual sensors and then used by a back-projection algorithm to calculate concentration profiles from measured sensor values. Limitations in linearity over the sensing area are reduced by applying a filter to the images. The filtered back-projection algorithm is tested both on uniformly and on artificially produced non-uniformly distributed solids' flows.

We describe the design and use of a 48 mm diameter, liquid-helium-cooled MRI receiver coil and DC SQUID pre-amplifier. Comparison of images of a non-conducting room temperature test object collected with the SQUID-based system and those collected with an equivalent-area room-temperature surface coil show that the SQUID system SNR is approximately a factor of four greater, despite a 15 mm vacuum gap between sample and coil in the SQUID case. SQUID images of the lower arm also display improved SNRs over those of the room-temperature coil, this time by a factor of between two and three, and as a result reveal greater anatomical detail. We show that the performance is currently limited by inductively coupled losses from metal components in the imager, but that, by using the same system in a whole-body imager, the SNR of SQUID images of the arm will exceed the room-temperature coil's performance by a factor of between 2.8 and 4.5. We believe that these are the first magnetic resonance images of a living sample to have been produced with a SQUID-based receiver.

This paper deals with the question of whether an inexpensive optical sensor head, a so-called CD pick-up, from a compact disc player system can be used for simultaneously directing light into and detecting light received from an optical fibre. The investigation shows that the CD pick-up is well suited for intensity-based fibre-optic sensors. The benefit of using a CD sensor head is that it is a small-sized module including a diode laser, driver, detector, signal conditioning and lens system. Furthermore, the study shows that the CD pick-up may be used for fibre-optic interferometry as well.

Entries marked by * appear here for the first time. 1997 February 10 IEE E4 Group Coll. on Industrial Inspection, London, UK Details: E R Davies, Royal Holloway, University of London, UK. Telephone: +44 (0)1784 443497, e-mail: E.R.Davies@rhbnc.ac.uk 16--21 Optical Fiber Communication Conf., Dallas, TX, USA Details: Optical Society of America, Conference Services Department, 2010 Massachusetts Ave., NW, Washington DC 20036-1023, USA * 26 Optics and Optical Diagnostics in Combustion, London, UK Details: D P Towers, Rover Group, Applied Optics Laboratory, Gaydon Test Centre, Banbury Road, Lighthorne, Warwick CV35 0RG, UK. Telephone: +44 (0)1926 643236, fax: +44 (0)1926 643030, e-mail: 101512.3606@compuserve.com March 2--6 10th Meeting on Optical Engineering in Israel, Jerusalem, Israel Details: Association of Engineers and Architects, PO Box 3082, Tel-Aviv, 61030, Israel * 17--21 Materials Under Stress: An Introduction to Fracture Mechanics and Fatigue, Guildford, UK Details: Margaret Morgan, Short Course Organiser, Department of Materials Science and Engineering, University of Surrey, Guildford, Surrey GU2 5XH, UK. Telephone: 01483 259378, fax: 01483 259508, e-mail: M.Morgan@Surrey.ac.uk * 24--26 Visual Scales: Photometric and Colormetric Aspects, Teddington, UK Details: Julie Taylor, National Physical Laboratory, Queens Road, Teddington TW11 0LW, UK. Telephone +44 (0) 181 943 6539, e-mail: jafw@newton.npl.co.uk 25--26/27 1st Int. Symp. on Multi-Body Dynamics: Monitoring and Simulation Techniques, Bradford, UK Details: MBD-MST Symposium, Homer Rahnejat, Department of Mechanical Engineering, University of Bradford, West Yorkshire BD7 1DP, UK. E-mail: mbdmst@bradford.ac.uk, WWW: http://www.brad.ac.uk/research/mdbmst April * 14--18 Introduction to Materials Analysis: Methods for Bulk, Surface and Structural Characterisation, Guildford, UK Details: Margaret Morgan, Short Course Organiser, Department of Materials Science and Engineering, University of Surrey, Guildford, Surrey GU2 5XH, UK. Telephone: 01483 259378, fax: 01483 259508, e-mail: M.Morgan@Surrey.ac.uk * 19--22 Scanning 97, Monterey, CA, USA Details: Mary K Sullivan, FAMS Inc., SCANNING 97 Program Committee, Box 832, Mahwah, NJ 07430-0832, USA. Telephone: (201) 818 1010, fax: (201) 818 0086, e-mail: fams@holonet.net, WWW: http://www.scanning-fams.org 22--24 MIOP '97: Microwave and Optronics Conf. and Exhibition on Microwaves, Radio Communications and Electromagnetic Compatibility, Sindelfingen, Germany Details: NETWORK GmbH, Wilhelm-Suhr-Str., 14, D-31558 Hagenburg, Germany. E-mail: schrade@networkgmbh.de, WWW: http://www.networkgmbh.de * 28--1 May Laboratory Health and Safety, Loughborough, UK Details: Joyce Bostock, Centre for Hazard and Risk Management, Loughborough University, Loughborough LE11 3TU, UK. Telephone: 01509 222175, fax: 01509 223991 May * 12--15 2nd Int. Conf. on Spectroscopic Ellipsometry, Charleston, SC, USA Details: David Aspnes, Physics Department, NCSU, Raleigh, NC 27695-8202. Telephone: (919) 515 4261, fax: (919) 515 1333, e-mail: aspnes@unity.ncsu.edu 18--23 Conf. on Lasers and Electro-Optics, Baltimore, MD, USA Details: Optical Society of America, Conference Services Department, 2010 Massachusetts Ave., NW, Washington DC 20036-1023, USA 18--23 Quantum Electronics and Laser Science Conf., Baltimore, MD, USA Details: Optical Society of America, Conference Services Department, 2010 Massachusetts Ave., NW, Washington DC 20036-1023, USA 19--23 ICRM'97, Gaithersburg, MD, USA Details: J M R Hutchinson, Radioactivity Group, NIST, Gaithersburg, MD 20899, USA * 20--22 Surface Analysis '97, Albuquerque, NM, USA Details: R J Simonson, Sandia National Laboratory, PO Box 5800, MS 1349, Albuquerque, NM 87185, USA. Telephone: (505) 272 7631, fax: (505) 272 7304, e-mail: rjsimon@sandia.gov June 9--11 10th Scandinavian Conf. on Image Analysis (IAPR), Lappeenranta, Finland Details: SCIA `97, Department of Information Technology, Lappeenranta University of Technology, PO Box 20, FIN-53851, Lappeenranta, Finland. E-mail: SCIA97@lut.fi, WWW: http://www.lut.fi/scia97 * 16--19 Machine Vision for Intelligent Vehicles and Autonomous Robots, Florence, Italy Details: Alberto Broggi, Dipartimento di Ingegneria dell'Inforazione, Universita` di Parma, I-43100 Parma, Italy. Fax: +39 521 905723, e-mail: broggi@CE.UniPR.it, WWW: http://WWW.CE.UniPR.IT/isata, http://WWW.spincom.com/isata July * 6--9 CRYO 97 (Low Temperature Microscopy and Analysis), York, UK Details: Royal Microscopical Society, 37/38 St Clements, Oxford OX4 1AJ, UK. Telephone: +44 (0) 1865 248768, fax: +44 (0) 1865 791237 August * 25--27 Inter-noise '97, Budapest, Hungary Details: Congress Ltd, 11-1026 Budapest, Szilagyi Erzsébet fasor 79, Hungary. Telephone: 36 1 212 0056, fax: 36 1 156 6581 September 1--4 5th Triennial Int. Symp. on Fluid Control, Measurement and Visualization, Hayama, Japan Details: FLUCOME Desk, Kintetsu International, 7th Floor Takakyu Building, 19 Kanda Matsunaga-cho, Chiyoda-ku, Tokyo 101, Japan 8--12 World Tribology Congr., London, UK Details: Conference Services Department (C491), Institution of Mechanical Engineers, 1 Birdcage Walk, London SW1H 9JJ, UK 8--12 7th Int. Conf. on Laser Anemometry Advances and Applications, Karlsruhe, Germany Details: B Ruck, Institut für Hydromechanik, Universität Karlsruhe, Kaiserstraße 12, 76128 Karlsruhe, Germany. Telephone and fax: +49 721 608 3897. 15--18 2nd Int. Coll. Micro-Tribology `97, Poland Details: Zygmunt Rymuza, Warsaw University of Technology, Institute for Design of Precise and Optical Instruments, Chodkiewicza 8/623, 02-525 Warszawa, Poland October 11--17 OSA'97 Annual Mtg, Long Beach, CA, USA Details: Optical Society of America, Conference Services Department, 2010 Massachusetts Ave., NW, Washington DC 20036-1023, USA 11--17 Interdisciplinary Laser Science Conf., Long Beach, CA, USA Details: Optical Society of America, Conference Services Department, 2010 Massachusetts Ave., NW, Washington DC 20036-1023, USA 1998 March 31--2 April Second Scientific Instrument Association Conf. and Exhibition, London, UK Details: SiA, PO Box 192, Watford, Herts WD1 8GF. WWW: http://www/interlab.co.uk/interlab July 13--16 9th Int. Symp. on Applications of Laser Techniques to Fluid Mechanics, Lisbon, Portugal Details: M V Heitor, Instituta Superior Técnico, Mechanical Engineering Department, 1096 Lisboa Codex, Portugal. Fax: 351 1 849 61 56 August 24--28 11th Int. Conf. on Experimental Mechanics, Oxford, UK Details: BSSM, Surrey Technology Centre, Surrey Research Park, 40 Occam Road, Guildford GU2 5YG, UK. Telephone: +44 (0)1483 295715. Fax: +44 (0)1483 573704.

This reviewer must start by declaring an interest: my first published paper, written with a senior member of the Department, described measurements of the polarization of the light of Comet Arend - Roland (1957). Looking back on that paper, I can see that we might have written up the results in a more convincing manner if this book had been available at that time. It was the brief appearance of that bright comet, however, that was responsible for the simplicity of our equipment. The author and I have also sat through a few astronomical lectures together, at which I found he was taking notes in his mother tongue of Dutch although the lecturer was speaking in English; and later we met again when observing in South Africa.

Not only is Tinbergen fully bilingual, but he is also equally at home in optical and radio astronomy. His interest in polarimetry goes back more than 25 years; this book has developed from a senior undergraduate course on the subject given at Leiden Observatory. The aim is to encourage an understanding of polarimetry, and increase its use whenever this is appropriate in astrophysical observations at any wavelength, from radio through infra-red and optical to ultra-violet and x-rays.

After a short introduction, which explains the arrangement of the other chapters, there is a description of polarized radiation, introducing the Stokes parameters and the Poincaré sphere, followed by a discussion of the new Stokes parameters after radiation has been modified by a polarizing, depolarizing or retarding component of a detector system. When the phase of a signal is relevant, Jones matrices must be used instead.

A chapter on the principles of instruments for polarimetry includes discussions of the determination of the zero points of both the position angle and degree of polarization, and of the errors which arise from the sidelobes of radio telescopes and ground reflections. The errors which can be caused in simple photometry if the radiation is polarized are also mentioned. Practical polarimeters for optical and for a radio and other spectral regions are described in the following chapter. Some examples of recent investigations, chosen more for the quality of the instrumentation than for the astronomy, are presented in the last chapter. Eight pages of suggested exercises, chosen to illustrate particular aspects of polarimetry, are followed by two very terse pages of hints. There are 11 pages of references, and four pages of index.

The author, in his preface, recommends reading the book quickly; to do this you may need the help of some cups of coffee. The book is full of good solid material, and many explanations are to be found only in the references. This has kept the size, and cost, of the book modest, for which the author is to be congratulated. He has allowed his sense of humour to enliven the text in a number of places, as on the title page, in the tabular historical summary, and on gamma-ray polarimetry, but to find these short passages you will have to ask your librarian to buy a copy, or, better still, buy your own.

This book presents a very useful insight into ultrasonic technology and is based on years of practical experience at the Slovak Technical University of Bratislava. Much of the technology presented has been developed as part of a long-term programme in machine control. In the main, the technology involves the application to air-borne ultrasonics. The book is therefore particularly useful for the engineer wishing to apply ultrasonic techniques for position monitoring, flow and wind velocity measurements.

The first chapter is an introduction to ultrasonic waves and this is followed by a chapter on transducers. Transducers covered include from capacitive, piezoelectric, magnetostrictive, electrical discharge (spark) and discharge microphone. In the latter cases, electrical excitation and detection circuits are presented. Chapter 4 deals with digital measuring methods. The design engineer new to ultrasonics will find this most useful as it describes methods aimed at achieving different levels of precision, using both phase and pulse methods. The principles of pulse-echo methods, especially applied to liquid level detection and measurement, are analysed. Again, practical issues are considered such as the surface quality. This chapter also considers the significant errors that can occur in level gauging caused by the variation of sound speed in air or other gases with temperature. Methods of overcoming these errors are considered including the use of parallel channels. The chapter deals at some length with coordinate position measurement using spark sources and distributed sensors, including methods of self-calibration. Liquid flow measurement in pipes is also considered in this chapter. Chapter 5 considers non-destructive testing from a fairly basic perspective. Chapter 6 analyses in greater detail the pulse methods for position and flow measurement and addresses the need for greater accuracy, in particular for the compensation of atmospheric influences. The last chapter looks at different instruments used in industrial control and monitoring, and a number of commercially available systems are described.

The causal reader will find this book very useful as it addresses many practical issues and makes recommendations on topics rarely found in textbooks. For instance, section 3.1.2 discusses the capacitance transducers for air ultrasonics and mentions many critical aspects of design. However, the reader wishing to know more may be rather frustrated as many issues are dealt with rather superficially, a particular example being the electrodes and underlying substrate. Four configurations are given in figure 3.1 but no discussion about their relative merits, nor any further references, is given, a weakness in a number of other places. This book is therefore not one for the purist. This is confirmed by a more careful examination of the equations and presentation which show a number of inconsistencies. One of the major problems is the inconsistent use of symbols. For instance, on page 7 lower case p and upper case P are used for acoustic pressure, and on pages 40 and 41, the subscript is used without explanation, presumably a misprint which should read 33. The reader also needs to take care in interpreting some of the equations. For instance, equation 2.8 is intended to give the power in an ultrasonic beam based on its intensity and area. However, it uses the parameter s which is referred to as a `unit area'. This equation should take account of the actual area of the beam and its intensity distribution, and if it assumed that the beam has constant intensity over the beam area, the parameter s should then be the beam area and not unit area. These are just some of the instances where the reader needs to be careful in interpreting the text.

Overall, this is a useful book for the engineer new to ultrasound and even for the more experienced it represents a very valuable collection of technical data.

This book is a timely collection of recent results and developments in chemical and biochemical sensors based on optical planar and cylindrical waveguides. It is well known that both fields (chemical and biochemical sensing, and optical planar and fibre waveguides) are enormous as is this book. Personally I find that the book tries to cover too much in too little space. As a result, it fails to meet the expectations of readers who are attracted by its title.

In order to cover as much as possible, most of the subjects dealt with in the book give large lists of references for readers to follow up. Fundamental concepts in the fields of chemical and biochemical sensing as well as optics and photonics are only briefly included so the book is not a self-contained text. Interested readers will have to follow up the related references and publications in order to master the art of a particular sensor or technology involved. Nonetheless, the book does cover the broad surface of both fields.

The book is divided into four parts. Parts I and II cover the basics of chemical and biochemical sensing. The basics of optics and photonics are covered in Part III. The combination of the chemical and biochemical sensing with optics and photonics is dealt with in Part IV, which also addresses the practical sensors, sensing systems and technologies.

Part I, which contains two chapters, introduces the basic concept of chemical reactions, kinetics and shape recognition, which are essential in chemical sensing. Practical sensors are used as examples to demonstrate the importance of those concepts. Part II, which contains two chapters, introduces the concepts of indicators, receptors and labels which are widely used in chemical and biochemical sensing. A few commonly used indicator compounds are described, and the technique in which these compounds are immobilized on a support is examined. Part III, which contains five chapters, briefly addresses the basic theory of optics, the concepts in optics and photonics. The optical properties of optical fibres and planar waveguides are introduced. The basic optical measurement techniques are also examined. The concepts of a few practical light sources and photodetectors are introduced. Active and passive optical components such as filters, multiplexers and polarization optical devices are briefly addressed.

A brief introduction to a range of chemical and biochemical sensors is given in Part IV, which contains two chapters. The recent results of these sensors and sensing systems are reported in these chapters, some even to the point of a bulleted list with reference number. The organization of these two key chapters of the book, appears to have been rushed by the authors and no future prediction or suggestion is given on the direction in which the field should go. Readers may have to trace all references in order to see the future of this technology.

This is a good introductory book for readers working in this area who are not familiar with either chemical and biochemical sensing and/or optical fibres and waveguides. Even so, fundamental concepts in the fields of chemical and biochemical sensing as well as optics and photonics are covered to a lesser depth than can be found in many undergraduate texts written for that field. For readers who are already familiar with the basic concepts in these fields, this book offers a brief summary of the recent results and developments with a large list of reference and publications for readers to follow up.

In summary, this book scratches the broad surface of this field. The essential fundamental concepts, recent results and development are briefly presented. This is not a book for anyone who is interested in probing deeper into this subject. It is a book for those who wish to know a bit of everything in this field and have not yet decided whether to probe deeper into the subject. The book is fairly well presented in this regard.

This book introduces the new student to basic electronic logic theory, up to the beginnings of circuit implementation; it is a revision of a book which has been in use for a decade.

The author begins with the representation of numbers, and then covers binary operations, combinational logic, sequential logic, digital systems, arithmetic processors, and practical circuits. This seems appropriate for the intended student audience; it will perhaps be less attractive to the average reader of MST, who may be more interested in finding the easiest way of implementing a required logic function with existing components. On the other hand, with the increasing use of programmable logic in the design of research and measurement equipment, the coverage of the efficient building up of complex functions from basic logic elements will be found valuable.

Nevertheless, I would like to have seen a little more material on the nature of the various functions presently available in common small- and medium-scale integrated circuits, and an indication of techniques and precautions which are advisable in the construction of working systems.

The book is clearly written and well printed, with few typographical errors. There are worked examples, with problems for the student and answers at the back.

J R Stockton