Dissertation Table of Contents
Title: Time-Frequency Acoustic Processing and Recognition:
Analysis and Analog VLSI Implementations
- Abstract ii
- Acknowledgements iii
- List of Figures vii
- List of Tables xii
- 1 Introduction 1
- 1.1 Introduction 1
- 1.2 Mapping the Time-Frequency Plane 6
- 1.2.1 Current-mode filterbanks 8
- 1.2.2 Acoustic Transient Recognition 9
- 1.2.3 Analog VLSI implementation of the transient classifier 10
- 1.2.4 Overview: Learning and Continuous Speech Recognition 11
- 2 Continuous Wavelet Transform 14
- 2.1 Introduction to the 1-Dimensional Continuous Wavelet Transform 14
- 2.2 CWT vs. DWT 16
- 2.3 Gabor Logons and Wavelets 18
- 2.4 Complex Demodulation 20
- 2.5 Complex Demodulation in the Continuous Wavelet Processor 23
- 2.6 Post-processing 27
- 2.7 An Analog CWT Processor 28
- 2.8 Generating carrier sinusoids 29
- 2.9 Analog multiplication 30
- 2.10 Wavelet Gaussian Function 30
- 2.11 Wavelet chip slice 34
- 2.12 Chip Specifications 34
- 2.13 Limitations of the Architecture 36
- 2.14 Variations on an Architecture 37
- 2.15 A Mixed-Mode Wavelet Processor 38
- 2.16 Details of the Bit-Sequence-Finding Algorithm 42
- 2.17 Sequence generation 44
- 2.18 Results and implementation 46
- 2.19 Modulation Multiplier 49
- 2.20 Switch-Cap Wavelet Gaussian Function 50
- 2.21 Output Time Multiplexing 52
- 2.22 Wavelet chip slice 53
- 2.23 Experimental Results 55
- 2.24 Extensions of the Research 58
- 2.25 Summary 61
- 3 Current-Mode Filterbank Frontend 62
- 3.1 Time-Frequency Representations using Filterbanks 62
- 3.2 Parallel Filterbanks for Transient Classification 63
- 3.3 Current-Mode Filters for Current-Mode Applications 64
- 3.4 High-Level Simulations of the Filterbank Frontend 66
- 3.5 Introduction to Translinear Circuits and Log-domain Filtering 70
- 3.6 Principles of log-domain synthesis 73
- 3.7 First-Order Circuit synthesis 76
- 3.8 Designing second-order s 78
- 3.9 Technology limitations for low-frequency filter design 83
- 3.10 Layout Considerations for VLSI Log-Domain Circuits 86
- 3.11 Current-Mode Circuits for Non-Filtering Applications 89
- 3.12 Signal Rectification and Smoothing 89
- 3.13 Signal Rectifier 90
- 3.14 Signal Peak-Peak Detector 91
- 3.15 L-1 Normalization Array 94
- 3.16 Experimental Results 97
- 3.17 Summary 105
- 4 Acoustic Transient Processing 106
- 4.1 Introduction 106
- 4.1.1 The Problem of Speech Recognition 106
- 4.1.2 Acoustic Transients 107
- 4.2 Algorithms 108
- 4.2.1 Simplifying The Correlation Equation 112
- 4.3 Simulations 119
- 4.3.1 The Hopkins Electronic Ear (HEEAR) Processor 120
- 4.3.2 Simulating the Acoustic Transient Baseline Algorithm 121
- 4.3.3 Optimizing Correlation Algorithms 123
- 4.3.4 Simulations of different zero-mean representations 125
- 4.3.5 High-Level Simulations of ATP Mixed-Mode VLSI Hardware 128
- 4.3.6 Optimization of the classifier using per-class gains 128
- 4.3.7 System Robustness 131
- 4.3.8 Research Directions 133
- 4.3.9 Remarks 134
- 4.4 Hardware Implementation of the Acoustic Transient Processor 135
- 4.4.1 Current-switching Memory Array 135
- 4.4.2 Bucket Brigade Device 138
- 4.4.3 Circuit input 140
- 4.4.4 Characterizations of the VLSI Hardware 141
- 4.4.5 Experimental Results 144
- 4.4.6 Summary 147
- 4.5 The Digital ATP 149
- 4.6 Digital correlator custom VLSI architecture 149
- 4.7 Digital correlator semicustom FPGA architecture 151
- 4.8 The Switch-Capacitor Frontend 156
- 4.9 Experimental results of the trinary-trinary correlation hardware 161
- 4.9.1 Method of input segmentation 161
- 4.9.2 Method of template generation 163
- 4.9.3 Experimental Results 164
- 5 Learning and Speech Recognition 171
- 5.1 Automatic Template Learning for Template-Based Correlation 171
- 5.2 Average-Value Templates 172
- 5.3 Deterministic Methods: Statistical Component Analysis 174
- 5.4 Support Vector Machines 177
- 5.5 Heuristic Methods (Unnikrishnan/Hopfield) 178
- 5.6 Biologically-Inspired Methods 183
- A Linearity of a Transconductance Amp 187
- B scshape Matlab Code for Sine Sequence Generation 190
- C Correlation with Time Differentiation 195
- C.1 Proof of validity of the pipelined architecture 198
- D Simulation of the ATP Frontend 201
- E Simulation of the ATP Correlator 209
- F Optimizing per-class gains in the ATP 214
- Bibliography 220
- Vita 227
Last updated: October 11, 2005 at 11:34pm