The Book End

Low Level Measurements: Precision DC Current, Voltage and Resistance Measurements

Joseph F. Keithley
Keithley Instruments Inc.
214 pages; no charge

This book is intended as a practical guide to making precision measurements of low level DC signals. It provides a comprehensive overview of the theoretical and practical considerations involved in measuring low currents, high and low resistances, and low voltages. The book describes many common sources of errors and ways to minimize them to make successful high impedance measurements. In addition, practical low voltage and resistance measurement methods and applications are discussed.

The first section describes theoretical measurement limits and digital multimeter limitations. Various measurement instruments are described and instrument specifications such as accuracy, derating, noise and noise rejection, and speed are explained. Basic circuit designs are given for voltmeters, ammeters, coulombmeters, ohmmeters and combination meters.

Section 2 describes high impedance measurements beginning with voltage measurements. Low current measurements are explained, including topics such as leakage currents, noise and source impedance, zero drift, generated currents, voltage burden and overload protection. Constant voltage and current methods are described as well as the characteristics of high value resistors.

Section 3 covers low impedance measurements, including low voltage measurement characteristics and low resistance measurement properties. Section 4 discusses the growing range of applications in low level measurements as well as the most appropriate instruments and test techniques to use to solve specific test and measurement challenges. The final section offers an instrument selection guide for specific applications.

This fifth edition is offered free of charge to individuals seeking a better understanding of low level measurement techniques. The book is an easy-to-read explanation of low level measurements and the methods, care and precautions necessary to make these measurements accurately and easily. The book serves as an excellent reference handbook and practical guide in this area.

To order this book, contact:
Keithley Instruments Inc.,
28775 Aurora Rd.,
Cleveland, OH
(440) 248-0400.

Advanced High-frequency Radio Communications

Eric E. Johnson, Robert I. Desourdis, Jr., Gregory D. Earle, Stephen C. Cook and Jens C. Ostergaard
Artech House Inc.
376 pages; $85, £65

This book describes standardized state-of-the-art and advanced techniques used by automated high frequency (HF) radio equipment to provide primary and backup communication links and networks within the global information infrastructure. In addition to general information on HF radio, the book contains the only exposition to date on the US military and federal standards for automated HF systems.

Chapter 1 provides a historical perspective of radio standards and a description of a shipboard HF e-mail implementation. Chapter 2 includes quantitative descriptions of HF ground-wave and meteor-scatter propagation. Chapter 3 provides a tutorial describing antenna design and performance parameters as well as a description of numerical modeling tools and techniques. Digital modems for HF radio are discussed in Chapter 4 as well as an update to Pennington’s review of HF modem development in the late 1980s.

Chapter 5 overviews protocol layers that build upon HF modems to provide nearly transparent communications over HF channels. Chapter 6 describes a protocol suite that has been defined for evaluating and selecting HF channels, establishing links and exchanging messages using the automatic link establishment (ALE) waveform and frame structure. Chapter 7 discusses the linking protection technique developed for use with second-generation ALE employing time-varying encryption of ALE transmissions to authenticate those transmissions. Chapter 8 describes a high performance data link protocol that uses advanced HF data modems and shows the position of this protocol function in the hierarchical HF system model. Finally, Chapter 9 covers HF radio networking.

This book is intended for seasoned HF radio engineers who wish to learn automated HF station technology. However, newcomers may quickly increase their knowledge of modern HF radio systems as well.

To order this book, contact:
Artech House Inc.,
685 Canton St.,
Norwood, MA 02062
(781) 769-9750, ext. 4002; or

Portland House,
Stag Place, London
+44 (0) 171 973 8077.