Temperature- and Supply Voltage-Independent Time References for Wireless Sensor Networks (eBook)

Preface 7
Contents 8
Abstract 14
About the Authors 16
Abbreviations 19
Symbols 21
Figures 31
Tables 50
1 Introduction 52
1.1 Historical Introduction 52
1.1.1 Electromagnetic Transmission 54
1.1.2 The Vacuum Tube 59
1.1.3 The Invention of the Transistor 62
1.2 Wireless Sensor Networks 68
1.2.1 RFID Adoption 68
1.2.2 Challenges in RFID Design 69
1.2.3 The Pinballs Framework 69
1.2.4 Architecture of an RFID Tag 74
1.3 Focus and Outline of this Work 77
Part ITheoretical Background on Oscillatorsand Time References 80
2 Oscillators and Time References 81
2.1 Introduction 81
2.2 The Phase Space Description of an Oscillator 82
2.2.1 The Phase Space Description 82
2.2.2 One-Dimensional Systems 82
2.2.3 Two-Dimensional Systems 84
2.2.4 The van der Pol Oscillator 86
2.2.5 n-Dimensional Systems 89
2.3 Minimum Requirements for a Time Reference 92
2.3.1 An Energy Reservoir and a Resistor 93
2.3.2 Two Different Energy Reservoirs 94
2.3.3 Harmonic Versus Relaxation Oscillators 96
2.4 Representation of an Oscillator Signal 97
2.4.1 Oscillator Signals in the Time Domain 97
2.4.2 Oscillator Signals in the Frequency Domain 99
2.5 Properties of an Oscillator 102
2.5.1 The Quality Factor 103
2.5.2 Stability of an Oscillator Signal 109
2.6 Conclusion 109
3 Jitter and Phase Noise in Oscillators 110
3.1 Introduction 110
3.2 Noise Sources 111
3.2.1 Noise in a Resistor 112
3.2.2 Noise in a P-N Junction 112
3.2.3 MOS Transistor Noise 113
3.3 The Phase Noise Spectrum 113
3.3.1 The Noise Model of Leeson 114
3.4 The Phase Noise Theory of Hajimiri 117
3.4.1 Generation of the Phase Noise Spectrum 117
3.4.2 Extensions to the Theory of Hajimiri 123
3.4.3 Calculation of the ISF 125
3.4.4 Evaluation of Hajimiri's Theory 127
3.5 Nonlinear Noise Theories 128
3.5.1 The Lorentzian Spectrum 128
3.5.2 The Gaussian Spectrum 129
3.5.3 Evaluation 130
3.6 Phase Noise Versus Jitter 131
3.6.1 Definition of Jitter 131
3.6.2 Only White Noise Sources 134
3.6.3 Colored Noise Sources 134
3.6.4 General Calculation Method 135
3.7 The Q Factor and the Noise 136
3.7.1 The Theory of Leeson 136
3.7.2 The Theory of Hajimiri 136
3.8 Figures of Merit 137
3.8.1 The Phase Noise FoM 137
3.9 Conclusion 139
4 Long-term Oscillator Stability 140
4.1 Introduction 140
4.1.1 Causes of Frequency Drift 140
4.1.2 Organization of this Chapter 141
4.2 Building Blocks of an Oscillator 141
4.2.1 Linear Oscillator Systems 142
4.2.2 Nonlinear Oscillator Systems 143
4.2.3 Transistor Behavior 149
4.2.4 Properties of the Feedback Network 151
4.2.5 How to Obtain a Stable Oscillator? 155
4.3 Figures of Merit for Long-term Stability 157
4.3.1 Temperature FoM 157
4.3.2 Supply Voltage FoM 158
4.4 Oscillators for Low-Power Applications 159
4.4.1 Harmonic Integrated Oscillators 162
4.4.2 Relaxation Integrated Oscillators 170
4.4.3 Ring Oscillators 176
4.4.4 Other Implementations 178
4.4.5 Comparison of the Different Topologies 182
4.5 Conclusion 184
Part IIOscillator Designs for Temperatureand Voltage Independence 185
5 Design of Two Wien Bridge Oscillators 186
5.1 Introduction 186
5.1.1 The Wien Bridge Oscillator 187
5.2 The Temperature-Independent Wien Bridge 188
5.2.1 Basic Amplifier Structure 189
5.2.2 The Amplitude Regulator 193
5.2.3 Complete Circuit 195
5.2.4 Phase Noise Performance 195
5.2.5 Measurement Results 202
5.2.6 Conclusion on the Temperature-Independent Wien Bridge Oscillator 205
5.3 The Supply Voltage-Independent Wien Bridge Oscillator 206
5.3.1 The Oscillator Topology 207
5.3.2 The Proposed Oscillator 208
5.3.3 The LDO Regulator 211
5.3.4 Temperature Dependency of the Voltage-Independent Oscillator 214
5.3.5 Measurement Results 216
5.3.6 Conclusion on the Voltage-Independent Oscillator 219
5.4 General Conclusion 219
6 The Pulsed Oscillator Topology 220
6.1 Introduction 220
6.2 The Pulsed-Harmonic Oscillator Topology 221
6.2.1 The Energy Tank 222
6.3 Transient Behavior of the Energy Tank 223
6.3.1 The n-th Order Transfer Function 224
6.3.2 Realistic Second-Order Tanks 226
6.4 Behavior of the Pulsed LC Oscillator 230
6.4.1 Sensitivity to PW and MoI 233
6.4.2 Energy Losses During Oscillation 235
6.5 Phase Noise in the Pulsed LC Oscillator 236
6.5.1 Noise Injection During the Free-Running Period 236
6.5.2 Noise Injection During the Applied Pulse 240
6.5.3 Impact of the Different Noise Sources 241
6.6 Implementation of the Pulsed LC Oscillator 243
6.6.1 Design of the LC Tank 243
6.6.2 Design of the Differential Amplifier 245
6.6.3 The Counter 247
6.6.4 The Pulse Generator 247
6.7 Measurement Results 249
6.8 Conclusion 254
7 Injection-Locked Oscillators 255
7.1 Introduction 255
7.2 Injection Locking of an Oscillator 257
7.2.1 Lock Range of the Oscillator 257
7.2.2 Dynamic Behavior of the Locking Process 262
7.2.3 Frequency Beating 266
7.3 Phase Noise in the Injection-Locked Oscillator 268
7.3.1 Noise Model Using a Decreased Tank Impedance 269
7.3.2 A PLL-Based Noise Model 271
7.4 The Wirelessly-Locked Oscillator in 130nm 275
7.4.1 The Oscillator Topology 275
7.4.2 Techniques to Increase the Lock Range 279
7.4.3 Measurement Results 282
7.4.4 Conclusion on the 130-nm Injection-Locked Oscillator 283
7.5 The 40-nm Injection-Locked Receiver 284
7.5.1 The Clock Circuit 286
7.5.2 The Receiver Circuit 293
7.5.3 Measurement and Simulation Results 296
7.6 Conclusion 302
8 Oscillator-Based Sensor Interfaces 303
8.1 Introduction 303
8.2 PLL-Based Sensor Interfaces 304
8.2.1 Implementation of the PLL 304
8.3 The PWM-Based Sensor Interface 306
8.3.1 The Coupled Sawtooth Oscillator 307
8.3.2 Use in Combination with a Sensor 309
8.3.3 Transmission of the Output Signal 311
8.4 Jitter in the Coupled Sawtooth Oscillator 312
8.4.1 Jitter due to Sensor Noise 313
8.4.2 Jitter from the Differential Pair 316
8.4.3 Jitter due to the Current Source 318
8.4.4 Noise Propagation to the Sensor Interface Output 319
8.4.5 A/D-Converter FoM 323
8.5 Implementation of the Sensor Interface 324
8.5.1 Implementation in 130 nm CMOS 324
8.5.2 Implementation in 40 nm CMOS 328
8.5.3 Measurement Results 334
8.6 Conclusion 338
Part IIIWireless Sensor Nodes 339
9 Design of a Low-Power Wireless RFID Tag 340
9.1 Introduction 340
9.2 Architecture of the Wireless Tag 341
9.2.1 The Clock and Receiver Circuit 342
9.2.2 The UWB Transmitter 343
9.2.3 The Sensor Interface 344
9.2.4 The Digital Logic 345
9.3 Measurement Results 347
9.4 Conclusion 350
10 Conclusion 351
10.1 Comparison to the State of the Art 352
10.1.1 The Wien Bridge Implementations 352
10.1.2 The Pulsed-Harmonic Oscillator 353
10.1.3 The Injection-Locked Oscillators 355
10.1.4 The Sensor Interface 355
10.1.5 The Wireless Tag 356
10.1.6 General Conclusions 356
10.2 Main Contributions 357
10.3 Suggestions for Future Work 358
A Definitions and Conventions Used Throughout the Work 360
A.1 The Fourier Transform and Fourier Series 360
A.1.1 Non-periodic Waveforms 360
A.1.2 Periodic Waveforms 363
A.2 The Autocorrelation and PSD of a Signal 365
A.2.1 The Autocorrelation 367
A.2.2 The Power Spectral Density 368
A.3 Generalized and Special Functions 369
A.3.1 The Dirac Delta Function 369
A.3.2 The Step Function 370
A.3.3 A Rectangular Pulse 371
A.3.4 A Triangular Pulse 371
A.3.5 The Derivative Triangular Pulse 372
B Influence of a Nonlinear Amplifier 373
B.1 Derivation of Eq. (4.37) 373
B.2 Waveform in a Nonlinear Harmonic Oscillator 374
B.2.1 The Feedback Network 375
B.2.2 The Nonlinear Amplifier 376
B.2.3 Application to a Known Network 378
B.3 Proof of Eq. (4.42) 379
C Measurement Issues for Jitter and Phase Noise 382
C.1 White Noise Jitter Divergence 382
C.1.1 Frequency Fluctuations as a Noise Measure 384
C.1.2 Relation Between the Variance and the PSD 385
C.2 Colored Noise Jitter 386
C.2.1 Frequency Fluctuations as a Colored Noise Measure 386
C.2.2 The Allan Variance 387
C.2.3 The Use of Structure Functions 389
D Comparison to the State of the Art 394
References 401
Index 417