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Course #11
Digital Signal Analysis Techniques:
Time, Frequency, and
Spatial Algorithms
Spring 2011. Location to be decided.
INSTRUCTOR
Professor S. Lawrence Marple
Jr.
Georgia Tech Research Institute, Smyrna GA, USA
TECHNOLOGY FOCUS
Conventional tools for analyzing and extracting the feature content of signals are filters (time content), Fourier transforms
(frequency content) and beamforming (spatial content). Alternative tools to these conventional techniques are able to produce
signal analysis results with finer temporal detail and higher spectral and spatial
resolution. This course goes beyond
available textbooks and extends these signal analysis tools to higher dimensions and multiple sensor channels.
COURSE CONTENT
This course introduces practical implementation of the latest research approaches to time series and spectral
analysis. The course uses a
systematic approach based on a signal modelling theme, while focusing on fast computational procedures that make the alternative higher
performance analysis techniques feasible to implement in practical applications. Of special focus are the extensions of fast computational
algorithms for high performance signal analysis techniques to multichannel, multi-dimensional, and non-stationary instantaneous time-frequency analysis applications, where there is little published implementation
literature.
The first three days focus on one-dimensional data sources. The following two days cover data from multi-channel and two-dimensional
sources, and single channel data with highly non-stationary features. Application examples using telecom, sonar, radar, seismic, and biomedical
data have been incorporated into the course. Emerging signal processing techniques in modern time series and spectral analysis,
including bandwidth extrapolation methods, non-stationary signal time-frequency analysis, and multi-resolution
(wavelet-based analysis) analysis, will be covered.
An extensive software toolbox (MATLAB and C) is provided students for all the algorithms and computational techniques introduced in
the course.
WHO SHOULD ATTEND
The expected background for students is some fundamental knowledge of Fourier
transforms, basic digital signal processing (filters, convolution, Fast Fourier
Transform [FFT]), basic matrix mathematical operations (matrix inverse, eigenvectors), and introductory random signals (correlation, spectral density). There is a review during the first day on these topics to introduce notation and to remind students of basic concepts. Some experience applying time and frequency domain techniques to signals would be helpful. This course provides alternative time and frequency domain analysis techniques. A number of data cases are used to demonstrate the practical use of the theoretical concepts.
Monday
Signal Analysis Tools and Classical Spectral Analysis
The first day reviews all the relevant concepts of traditional temporal
and frequency domain analysis of signals. We will establish some important
concepts for the advanced alternative temporal and frequency
(spectral) techniques covered in sequel course days.
- Complex Signal Representations
- Analytic Signals
- Matched Filters
- Issues in Spectral Estimation
- Concepts from Fourier Transform Theory
- Tutorial Review: Random Signal Theory
- Tutorial Review: Matrix Algebra Theory
- Resolution and Time-Bandwidth Uncertainty Principle
- Autocorrelation and Cross Correlation
- Power Spectral Density
- Window Selection
- Correlogram Method
- Periodogram Method
- Blackman-Tukey Method
Tuesday
Parametric and Autoregressive Methods
The most successful high performance analysis approach is based on autoregressive and linear prediction modelling and estimation. We
explore the basis for the high performance via a systematic modelling viewpoint, and illustrate the performance with actual data.
- Parametric Time Series Models: Autoregressive (AR), Moving Average (MA), and Autoregressive Moving Average (ARMA)
- Parameter Relationships among AR, MA, and ARMA Models
- Autocorrelation Relationships among Parametric Models
- AR, Linear Prediction, and Lattice Filters
- Levinson-Durbin Algorithm
- Reflection Coefficients
- Maximum Entropy Analysis
- ARMA Spectral Estimation
- MA Spectral Estimation
- AR Spectral Estimation: Yule-Walker algorithm, Burg algorithm, least squares
linear prediction algorithms
- AR Model Order Selection
- Adaptive AR Spectral Analysis Algorithms: LMS and Fast RLS
computational algorithms
Wednesday
Exponential Frequency Estimation and Minimum Variance Spectra
Even higher performance for finding signal feature extraction is
achieved using minimum variance and eigenanalysis approaches, at
a computational cost increase. We explore the tradeoffs.
- Prony’s Method
- Damped Exponential Parameter Estimation
- Relationship to AR Methods
- Least Squares Prony Algorithms
- Noise Excision by Eigenanalysis/Principal Components Analysis
- Minimum Variance Estimation: Derivation and relationship to AR spectral estimation, signal and noise subspace concepts
- Pisarenko’s Technique
- MUSIC Algorithm
- ESPRIT Algorithm
Thursday
Multi-Channel and Two-Dimensional Spectral Analysis
Some of the techniques discussed the first three days are extended to multi-channel (multiple sensors) and higher dimensional data
situations. We cover many of the important extensions and show that higher estimation performance is achieved, sometimes with unexpected
artefacts for which a user needs to be aware.
- Multi-Channel (MC) Spectral Analysis: MC transform theory, MC random
process theory
- MC Classical Spectral Estimators
- MC AR/MA/ ARMA Processes
- MC Block-Levinson Algorithm
- MC AR Spectral Estimators
- MC Minimum Variance Spectral Analysis
- Two-Dimensional (2D) Spectral Analysis: 2D transform theory, 2D random process theory
- 2D Minimum Variance Spectral Algorithm
- 2D Autoregressive and Linear Prediction
- Time Delay Estimation by Application of MC Analysis
- Bandwidth Extrapolation via Linear Prediction Methods
- Relationship of Temporal and Spatial Spectral Analysis Techniques
- High Resolution Direction Finding and Beamformation
Friday
Non-Stationary Time-Frequency Analysis (TFA)
Some additional performance tradeoffs and issues concerning non-stationary (time-varying) signal analysis will be summarized, again using
actual data to illustrate the tradeoffs.
- Time-Recursive AR Estimation
- Short Time Fourier Transform
- Linear and Quadratic Time-Frequency Representations
- Short Time Fourier Transform (STFT)
- Wigner-Ville Distribution
- 2D Methods of TFA
- Ambiguity Functions in TFAs
Multi-Resolution and Deconvolution Analysis
- Alternative Multi-Resolution Basis Functions to Fourier Transform Frequency Representation
- Scaling (time compression/time expansion) Properties of Analyzing Wavelets for Time-Frequency Analysis
- Scalograms vs Time-Frequency Grams
- Time Domain, Least Squares, and Frequency Domain Deconvolution Techniques
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