This chapter gives a brief introduction to the basic terms, techniques and mathematical guidelines for a better interpretation of the measured quantities and provides an overview of more recent developments related to the interpretation of volt and ohm. This chapter is prepared as a refresher module for the basics related to measurements and some developments in the past decade on volt and ohm representation, etc. Rigorous mathematical treatment of errors, statistical techniques and analysis of results, etc., are purposely eliminated.

Modern design trends use the power and precision of the digital world of components to process analogue signals. However, the link between the digital/processing world and the analogue/real world is based on the analogue-to-digital and digital-to analogue converter ICs, which generally are grouped together as the data converters. Until about 1988, engineers had to stockpile their most innovative A-to-D converter (ADC) designs, because available manufacturing processes simply could not implement those designs onto monolithic chips economically. Prior to 1988, except for the introduction of successive approximation, integrating and flash ADCs, the electronics industry saw no major changes in monolithic ADCs. Since then, manufacturing processes have caught up with the technology and many techniques such as sub-ranging flash, self-calibrating, delta/sigma, and many other special techniques have been implemented on monolithic chips.

An oscilloscope display presents far more information than that available from other test and measuring instruments such as frequency counters or digital multimeters. With the advancement of the solid state technology now applied to the development of modern oscilloscopes, it is possible to divide the range of oscilloscopes into two major groups: namely, analogue oscilloscopes and digital storage oscilloscopes. Signals that can be handled by the modern instruments now reach 50 GHz for repetitive signals and beyond 1 GHz for non-repetitive signals. This chapter provides the essential basics for oscilloscope users.

Counting the occurrence of electrical events was a primary concern of electrical engineering, even in the era of vacuum tubes. The firstgeneration electronic counters were designed using vacuum tubes; these were bulky, heavy and power hungry. The second-generation counters introduced in the early 1960s were considerably smaller owing to transistorised circuitry even though the basic specifications of the instruments remained more or less the same as for the vacuum tube versions. The availability of digital integrated circuits at the end of 1960s led to the birth of a third generation with better performance and features. With the introduction of LSI and VLSI components, a fourth generation of powerful counters has appeared in the market within the past 15 years. Very recently, related families of instruments, such as modulation domain analysers, have also been introduced into the industry, thus bringing unique methods for viewing complex modulated signals in the modulation domain.

All electrical signals can be described either as a function of time or of frequency. When we observe signals as a function of time they are called the time domain measurements. Sometimes, we observe the frequencies present in signals, in which case they are called the frequency domain measurements. The word spectrum refers to the frequency content of any signal. When signals are periodic, time and frequency are simply related; namely, one is the inverse of the other. Then we can use the Fourier series to find the spectrum of the signal. For non-periodic signals, a Fourier transform is used to get the spectrum. This chapter provides an overview of fast Fourier transform (FFT) techniques, as applied to dynamic signal analysers (or FFT analysers) or DSOs where spectrum components of a time varying signal are to be displayed. In addition, the essential principles and applications of swept-tuned spectrum analysers are discussed, because spectrum observations of higher frequency signals, such as those used in communications systems, are still beyond the capability of FFT analysers.

This chapter provides an introduction to common instrument interfaces and VLSI testing. Technical details of two matured standards such as the IEEE-488 interface system and the VME bus extension for instrumentation (VXIbus) are given, along with an insight into the evolution of the standards and the future trends.

During the period 1975-1985 many instruments designers recognised the value of microprocessors in the design of instruments. Digital storage scopes, function generators, and frequency counters, etc., were the early families of instruments that made use of the microprocessor subsystems. High performance analogue oscilloscopes were another classic example of use of microprocessor subsystems for add-on fea tures and performance. FFT analysers were yet another kind of instruments to use digital signal processors (DSPs).

This chapter is inserted as a special one because calibration and metrology have reached an important dimension recently with management standards such as the ISO 9000 series, etc. The chapter is prepared not as a comprehensive document describing all possible parameters and common instruments, but as a guideline for a test engineer to be familiar with modern concepts and practices in metrology, calibration and traceability, etc. The list of references is comprehensive enough if one needs a broad idea of calibration and metrology practices as applicable in the field.