Modern Measurements

PREFACE xv ACRONYMS xvii I FUNDAMENTALS 1 1 MEASUREMENT MODELS AND UNCERTAINTY 3 Alessandro Ferrero and Dario Petri 1.1 Introduction 3 1.2 Measurement and Metrology 4 1.3 Measurement Along the Centuries 5 1.3.1 Measurement in Ancient Greece 6 1.3.2 Measurement in the Roman Empire 6 1.3.3 Measurement in the Renaissance Period 7 1.3.4 Measurement in the Modern Age 8 1.3.5 Measurement Today 9 1.4 Measurement Model 10 1.4.1 A First Measurement Model 11 1.4.2 A More Complex Measurement Model 16 1.4.3 Final Remarks 19 1.5 Uncertainty in Measurement 20 1.5.1 The Origin of the Doubt 21 1.5.2 The Different Effects on the Measurement Result 23 1.5.3 The Final Effect 25 1.6 Uncertainty Definition and Evaluation 27 1.6.1 The Error Concept and Why it Should be Abandoned 28 1.6.2 Uncertainty Definition: The GUM Approach 29 1.6.3 Evaluating Standard Uncertainty 31 1.6.4 The Combined Standard Uncertainty 35 1.7 Conclusions 39 Further Reading 40 References 41 Exercises 41 2 THE SYSTEM OF UNITS AND THE MEASUREMENT STANDARDS 47 Franco Cabiati 2.1 Introduction 47 2.2 Role of the Unit in the Measurement Process 48 2.3 Ideal Structure of a Unit System 50 2.4 Evolution of the Unit Definition 52 2.5 The SI System of Units 53 2.6 Perspectives of Future SI Evolution 59 2.7 Realization of Units and Primary Standards 62 2.7.1 Meter Realization and Length Standards 65 2.7.2 Kilogram Realization and Mass Standards: Present Situation 66 2.7.3 Kilogram Realization: Future Perspective 67 2.7.4 Realization of the Second and Time Standards 69 2.7.5 Electrical Unit Realizations and Standards: Present Situation 71 2.7.6 Electrical Units Realization and Standards: Future Perspective 76 2.7.7 Kelvin Realization and Temperature Standards: Present Situation 78 2.7.8 Kelvin Realization and Temperature Standards: Future Perspective 79 2.7.9 Mole Realization: Present Situation 80 2.7.10 Mole Realization: Future Perspective 81 2.7.11 Candela Realization and Photometric Standards 82 2.8 Conclusions 83 Further Reading 83 References 84 Exercises 84 3 DIGITAL SIGNAL PROCESSING IN MEASUREMENT 87 Alessandro Ferrero and Claudio Narduzzi 3.1 Introduction 87 3.2 Sampling Theory 88 3.2.1 Sampling and Fourier Analysis 89 3.2.2 Band-Limited Signals 92 3.2.3 Interpolation 95 3.3 Measurement Algorithms for Periodic Signals 96 3.3.1 Sampling Periodic Signals 97 3.3.2 Estimation of the RMS Value 99 3.4 Digital Filters 102 3.5 Measuring Multi-Frequency Signals 106 3.5.1 Finite-Length Sequences 107 3.5.2 Discrete Fourier Transform 111 3.5.3 Uniform Window 113 3.5.4 Spectral Leakage 114 3.5.5 Leakage Reduction by the Use of Windows 116 3.6 Statistical Measurement Algorithms 119 3.7 Conclusions 120 Further Reading 121 References 122 Exercises 122 4 AD AND DA CONVERSION 125 Niclas Björsell 4.1 Introduction 125 4.2 Sampling 125 4.2.1 Quantization 126 4.2.2 Sampling Theorem 129 4.2.3 Signal Reconstruction 130 4.2.4 Anti-Alias Filter 133 4.3 Analog-to-Digital Converters 133 4.3.1 Flash ADCs 133 4.3.2 Pipelined ADCs 134 4.3.3 Integrating ADCs 134 4.3.4 Successive Approximation Register ADCs 135 4.4 Critical ADC Parameters 135 4.4.1 Gain and Offset 136 4.4.2 Integral and Differential Non-linearity 137 4.4.3 Total Harmonic Distortion and Spurious-Free Dynamic Range 139 4.4.4 Effective Number of Bits 139 4.5 Sampling Techniques 139 4.5.1 Oversampling 139 4.5.2 Sigma-Delta, ΣΔ 140 4.5.3 Dither 141 4.5.4 Time-Interleaved 142 4.5.5 Undersampling 142 4.5.6 Harmonic Sampling 143 4.5.7 Equivalent-Time Sampling 143 4.5.8 Model-Based Post-correction 144 4.6 DAC 144 4.6.1 Binary-Weighted 144 4.6.2 Kelvin Divider 145 4.6.3 Segmented 145 4.6.4 R-2R 145 4.6.5 PWM DAC 145 4.7 Conclusions 146 Further Reading 146 References 146 Exercises 147 5 BASIC INSTRUMENTS: MULTIMETERS 149 Daniel Slomovitz 5.1 Introduction 149 5.2 History 150 5.3 Main Characteristics 153 5.3.1 Ranges 153 5.3.2 Number of Digits and Resolution 155 5.3.3 Accuracy 158 5.3.4 Loading Effects 159 5.3.5 Guard 160 5.3.6 Four Terminals 161 5.3.7 Accessories 162 5.3.8 AC Measurements 164 5.3.9 Safety 167 5.3.10 Calibration 170 5.3.11 Selection 171 5.4 Conclusions 171 Further Reading 172 References 172 Exercises 173 6 BASIC INSTRUMENTS: OSCILLOSCOPES 175 Jorge Fernandez Daher 6.1 Introduction 175 6.2 Types of Waveforms 176 6.2.1 Sinewave 176 6.2.2 Square or Rectangular Wave 176 6.2.3 Triangular or Sawtooth Wave 176 6.2.4 Pulses 177 6.3 Waveform Measurements 177 6.3.1 Amplitude 177 6.3.2 Phase Shift 177 6.3.3 Period and Frequency 177 6.4 Types of Oscilloscopes 177 6.5 Oscilloscope Controls 181 6.5.1 Vertical Controls 183 6.5.2 Horizontal Controls 184 6.5.3 Trigger System 185 6.5.4 Display System 187 6.6 Measurements 188 6.6.1 Peak-to-Peak Voltage 188 6.6.2 RMS Voltage 188 6.6.3 Rise Time 188 6.6.4 Fall Time 188 6.6.5 Pulse Width 188 6.6.6 Period 190 6.6.7 Frequency 190 6.6.8 Phase Shift Measurements 190 6.6.9 Mathematical Functions 190 6.7 Performance Characteristics 191 6.7.1 Bandwidth 191 6.7.2 Rise Time 191 6.7.3 Channels 193 6.7.4 Vertical Resolution 193 6.7.5 Gain Accuracy 193 6.7.6 Horizontal Accuracy 193 6.7.7 Record Length 193 6.7.8 Update Rate 194 6.7.9 Connectivity 195 6.8 Oscilloscope Probes 195 6.8.1 Passive Probes 196 6.8.2 Active Probes 197 6.9 Using the Oscilloscope 199 6.9.1 Grounding 199 6.9.2 Calibration 199 6.10 Conclusions 199 Further Reading 200 References 200 Exercises 201 7 FUNDAMENTALS OF HARD AND SOFT MEASUREMENT 203 Luca Mari, Paolo Carbone and Dario Petri 7.1 Introduction 203 7.2 A Characterization of Measurement 206 7.2.1 Measurement as Value Assignment 206 7.2.2 Measurement as Process Performed by a Metrological System 209 7.2.3 Measurement as Process Conveying Quantitative Information 209 7.2.4 Measurement as Morphic Mapping 210 7.2.5 Measurement as Mapping on a Given Reference Scale 213 7.2.6 Measurement as Process Conveying Objective and Inter-Subjective Information 215 7.2.7 The Operative Structure of Measurement 216 7.2.8 A Possible Definition of “Measurement” 219 7.2.9 Hard Measurements and Soft Measurements 220 7.2.10 Multidimensional Properties 222 7.3 A Conceptual Framework of the Structure of Measurement 223 7.3.1 Goal Setting 225 7.3.2 Modeling 228 7.3.3 Design 241 7.3.4 Execution: Setup, Data Acquisition, Information Extraction and Reporting 243 7.3.5 Interpretation 245 7.4 An Application of the Measurement Structure Framework: Assessing Versus Measuring Research Quality 246 7.4.1 Motivations for Research Quality Measurement 246 7.4.2 Measurement Goal Definition 247 7.4.3 Modeling 250 7.4.4 Design 252 7.4.5 Execution 254 7.4.6 Interpretation 255 7.5 Conclusions 256 Further Reading 257 References 257 Exercises 260 II APPLICATIONS 263 8 SYSTEM IDENTIFICATION 265 Gerd Vandersteen 8.1 Introduction 265 8.2 A First Example: The Resistive Divider 265 8.3 A First Trial of Estimators 267 8.4 From Trial-and-Error to a General Framework 268 8.4.1 Setting up the Estimator 269 8.4.2 Uncertainty on the Estimates 270 8.4.3 Model Validation 271 8.4.4 Extracting the Noise Model 274 8.5 Practical Identification Framework for Instrumentation and Measurements 277 8.5.1 Dynamic Linear Time-Invariant (LTI) Systems 277 8.5.2 From Linear to Nonlinear Systems 280 8.5.3 Sine Fitting 280 8.5.4 Calibration and Compensation Techniques 282 8.6 Conclusions 282 Further Reading 283 References 283 Exercises 285 9 RELIABILITY MEASUREMENTS 287 Marcantonio Catelani 9.1 Introduction 287 9.2 Brief Remarks on the Concept of Quality 288 9.3 Reliability, Failure and Fault: Basic Concepts and Definitions 288 9.4 Reliability Theory 292 9.4.1 Reliability Models and Measures Related to Time to Failure 292 9.4.2 Life Distributions 298 9.4.3 Reliability Parameters 300 9.4.4 The Bath-Tube Curve 302 9.5 System Reliability Assessment 303 9.5.1 Series Configuration 304 9.5.2 Parallel Configuration 305 9.5.3 k-out-of-n Configuration 307 9.6 Analysis Techniques for Dependability 310 9.6.1 Failure Modes and Effect Analysis 311 9.6.2 Fault Tree Analysis 312 9.7 Conclusions 313 Further Reading 314 References 314 Exercises 315 10 EMC MEASUREMENTS 317 Carlo Carobbi 10.1 Introduction 317 10.2 Definitions and Terminology 318 10.3 The Measuring Receiver 321 10.3.1 Quasi-Peak Measuring Receivers 321 10.3.2 Peak Measuring Receivers 329 10.4 Conducted Emission Measurements 329 10.4.1 The Artificial Mains Network 329 10.4.2 The Current Probe 332 10.5 Radiated Emission Measurements 333 10.5.1 Antennas for the 9 kHz to 30 MHz Frequency Range 334 10.5.2 Antennas for the Frequency Range Above 30 MHz 335 10.5.3 Measurement Sites 339 10.6 Immunity Tests 343 10.6.1 Conducted Immunity Tests 343 10.6.2 Radiated Immunity Tests 346 10.7 Conclusions 347 Further Reading 348 References 348 Exercises 351 PROBLEM SOLUTIONS 353 INDEX 371