Preface
xvii
focuses on continuous spectral models (Autoregressive Moving Average (ARMA) models and
their AR and MA special cases), while Chapter 4 focuses on discrete spectral models (sinusoids
in noise). We have placed the filter-bank methods in Chapter 5, after Chapters 3 and 4, mainly
because the Capon estimator has interpretations both
as
an averaged AR spectral estimator and
as
a matched filter for line-spectral models, and we need the background
of
Chapters 3
and
4 to
develop these interpretations. The data-independent filter-bank techniques in Sections
5.1-5.4
can
equally well be covered directly following Chapter
2,
if
de~ired.
Chapter 6 considers the closely related problem
of
spatial spectral estimation in the context
of
array signal processing. Both nonparametric (beamforming) and parametric methods are consid-
ered, and both are tied into the temporal spectral estimation techniques considered in Chapters
2,
4, and 5.
The bibliography contains both modem and classical references (ordered both alphabetically
and by subject). We include many historical references
as
well, for those interested in tracing the
early developments
of
spectral analysis. However, spectral analysis is a topic with contriblltions
from many diverse fields, including electrical and mechanical engineering, astronomy, biomedical
spectroscopy, geophysics, mathematical statistics, and
econometrics-to
name a few. As such,
any attempt to document the historical development
of
spectral analysis accurately is doomed to
failure. The bibliography reflects our own perspectives, biases, and limitations; there is no doubt
that the list is incomplete, but we hope that it gives the reader an appreciation
of
the breadth and
diversity of the spectral analysis field.
The background needed for this text includes a basic knowledge of linear algebra, discrete-
time linear systems, and introductory discrete-time stochastic processes (or time series). A basic
understanding
of
estimation theory is helpful, though not required. Appendix A develops most
of
the needed background results on matrices and linear algebra, Appendix B gives a tutorial intro-
duction to the Cramer-Rao bound, and Appendix C develops the theory of model order selection.
We
have included concise definitions and descriptions
of
the required concepts and results where
needed. Thus, we have tried to make the text
as
self-contained
as
possible.
We
are indebted
to
Jian Li and Lee Potter for adopting a former version of the text in
their spectral estimation classes, for their valuable feedback, and for contributing to this book in
several other ways. We would like to thank Torsten Soderstrom, for providing the initial stimulus
for preparation
of
lecture notes that led to the book, and Hung-Chih Chiang, Peter Handel, Ari
Kangas, Erlendur Karlsson, and Lee Swindlehurst, for careful proofreading and comments and
for many ideas on and early drafts
of
the computer problems. We are grateful to Mats Bengtsson,
Tryphon Georgiou, K.V.S. Hari, Andreas Jakobsson, Erchin Serpedin, and A.ndreas Spanias for
comments and suggestions that helped us eliminate some inadvertencies and typographical errors
from the previous edition
of
the book.
We
also wish to thank Wallace Anderson, Alfred Hero,
Ralph Hippenstiel, Louis Scharf, and Douglas Williams, who reviewed a former version
of
the
book and provided
us
with numerous useful comments and suggestions.
It
was a pleasure
to
work
with the excellent staff at Prentice Hall, and we are particularly appreciative
of
Tom Robbins and
Scott Disanno for their professional expertise.
Many
of
the topics described in this book are outgrowths
of
our research programs in statistical
signal and array processing, and we wish to thank the sponsors
of
this research: the Swedish
Foundation for Strategic Research, the Swedish Research Council, the Swedish Institute, the