Higher-Order Spectral
Analysis Toolbox
For Use with MATLAB®
Ananthram Swami
Jerry M. Mendel
Chrysostomos L. (Max) Nikias
Computation
Visualization
Programming
User’s Guide
Version 2
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Higher-Order Spectral Analysis Toolbox User’s Guide
COPYRIGHT 1984 - 1998 by The MathWorks, Inc. All Rights Reserved.
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Printing History: May 1993
First printing
September 1995 Second printing
January 1998
Third printing
Contents
About the Authors
Tutorial
1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Polyspectra and Linear Processes . . . . . . . . . . . . . . . . . . . . . . 1-4
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Why Do We Need Higher-Order Statistics? . . . . . . . . . . . . . . . 1-10
Bias and Variance of an Estimator . . . . . . . . . . . . . . . . . . . . . 1-11
Estimating Cumulants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14
Estimating Polyspectra and Cross-polyspectra . . . . . . . . . . . . 1-15
Estimating the Power Spectrum . . . . . . . . . . . . . . . . . . . . . 1-15
Estimating Bispectra and Cross-Bispectra . . . . . . . . . . . . . 1-16
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-18
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19
Estimating Bicoherence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20
Testing for Linearity and Gaussianity . . . . . . . . . . . . . . . . . . . 1-22
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-24
i
Parametric Estimators, ARMA Models . . . . . . . . . . . . . . . . . . 1-26
MA Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-29
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-30
AR Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-31
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-32
ARMA Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-32
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-34
AR Order Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-34
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-35
MA Order Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-36
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-37
Linear Processes: Impulse Response Estimation . . . . . . . . . . . 1-37
The Polycepstral Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-38
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-39
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-41
The Matsuoka-Ulrych Algorithm . . . . . . . . . . . . . . . . . . . . . 1-41
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-42
Linear Processes: Theoretical Cumulants and Polyspectra . . 1-43
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-43
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-45
Linear Prediction Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-47
Levinson Recursion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-47
Trench Recursion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-49
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-50
Deterministic Formulation of FBLS . . . . . . . . . . . . . . . . . . . . . 1-53
Adaptive Linear Prediction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-54
RIV Algorithm: Transversal Form . . . . . . . . . . . . . . . . . . . . 1-56
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-57
RIV Algorithm: Double-Lattice Form . . . . . . . . . . . . . . . . . . 1-58
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-60
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-61
Harmonic Processes and DOA . . . . . . . . . . . . . . . . . . . . . . . . . 1-62
Resolution and Variance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-65
AR and ARMA Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-66
Pisarenko’s Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-67
Multiple Signal Classification (MUSIC) . . . . . . . . . . . . . . . . . . 1-68
Minimum-Norm Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-69
ESPRIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-70
ii
Contents
Criterion-Based Estimators . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-72
Cumulant-Based Estimators . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-74
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-75
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-77
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-79
Nonlinear Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-80
Solution Using Cross-Bispectra . . . . . . . . . . . . . . . . . . . . . . . . 1-80
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-82
Solution Using FTs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-82
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-83
Quadratic Phase Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-84
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-87
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-88
Time-Frequency Distributions . . . . . . . . . . . . . . . . . . . . . . . . 1-89
Wigner Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-90
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-93
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-94
Wigner Bispectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-94
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-96
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-97
Wigner Trispectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-98
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-99
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-100
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-100
Time-Delay Estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-101
A Cross-Correlation Based Method . . . . . . . . . . . . . . . . . . . . . 1-101
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-103
A Cross-Cumulant Based Method . . . . . . . . . . . . . . . . . . . . . . 1-103
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-105
A Hologram Based Method . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-105
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-107
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-107
iii
Case Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-108
Sunspot Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-108
Canadian Lynx Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-114
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-114
A Classification Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-120
Laughter Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-122
Pitfalls and Tricks of the Trade . . . . . . . . . . . . . . . . . . . . . . . . 1-131
Data Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-134
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-139
2
Reference
Function Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Higher-Order Spectrum Estimation: Conventional Methods . . 2-2
Higher-Order Spectrum Estimation: Parametric Methods . . . . 2-3
Quadratic Phase Coupling (QPC) . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Second-Order Volterra Systems . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Harmonic Retrieval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Time-Delay Estimation (TDE) . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Array Processing: Direction of Arrival (DOA) . . . . . . . . . . . . . . 2-4
Adaptive Linear Prediction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Impulse Response (IR), Magnitude and
Phase Retrieval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Time-Frequency Estimates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Demo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Prompting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Guided tour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Addenda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
iv
Contents
About the Authors
About the Authors
About the Authors
Ananthram Swami
Ananthram Swami received his B.Tech, M.S. and Ph.D. degrees in electrical
engineering from the Indian Institute of Technology at Bombay, Rice
University, and the University of Southern California, respectively. He has
held positions with Unocal, USC, CS-3 and Malgudi Systems. He is currently
a Senior SCEEE Research Fellow at the Army Research Lab, Adelphi, MD.
Dr. Swami has published over fifty journal and conference papers in the areas
of modeling and parameter estimation of non-Gaussian processes. He is
co-organizer and co-chair of the Eighth IEEE Signal Processing Workshop on
Statistical Signal and Array Processing, Corfu, Greece (June 1996).
Jerry M. Mendel
Jerry Mendel received his B.S. degree in Mechanical Engineering in 1959, his
M.S. in 1960, and his Ph.D. in 1963 in Electrical Engineering from the
Polytechnic Institute of Brooklyn, NY. Currently he is Professor of Electrical
Engineering at USC in Los Angeles.
Dr. Mendel is a Fellow of the IEEE, a Distinguished Member of the IEEE
Control Systems Society, a member of Tau Beta Pi, Pi Tau Sigma, and Sigma
Xi, and a registered Professional Control Systems Engineer in California. He
has authored more than 300 technical papers, three textbooks and four other
books related to his research in estimation theory, deconvolution, higher-order
statistics, neural networks and fuzzy logic.
Chrysostomos L. (Max) Nikias
Chrysostomos L. (Max) Nikias received his B.S. degree in Electrical and
Mechanical Engineering from the National Technical University of Athens,
Greece and his M.S. and Ph.D. degrees in Electrical Engineering from the State
University of New York at Buffalo in 1980 and 1982. Currently he is a
Professor of Electrical Engineering at USC in Los Angeles, where he is also
Director of CRASP and Associate Dean of Academic Research.
Dr. Nikias is a Fellow of the IEEE. He is the author of over 150 journal and
conference papers, two textbooks, a monograph, and four patents. He is
co-author of the textbook Higher-Order Spectral Analysis: A Nonlinear Signal
Processing Framework, Prentice-Hall, Inc. 1993.
vi