: : Digital signal processing

17-06-2008, 06:47 PM

Digital signal processing (DSP)


: Digital signal processing (DSP)

Digital signal processing (DSP)


Digital signal processing (DSP) is concerned with the representation of signals in digital form, and
with the processing of these signals and the information that they carry. Although DSP, as we know
it today, began to flourish in the 1960's, some of the important and powerful processing techniques
that are in use today may be traced back to numerical algorithms that were proposed and studied
centuries ago. Since the early 1970's, when the first DSP chips were introduced, the field of digital
signal processing has evolved dramatically. With a tremendously rapid increase in the speed of DSP
processors, along with a corresponding increase in their sophistication and computational power,
digital signal processing has become an integral part of many commercial products and applications,
and is becoming a commonplace term.
This book is concerned with the fundamentals of digital signal processing, and there are two ways
that the reader may use this book to learn about DSP. First, it may be used as a supplement to any
one of a number of excellent DSP textbooks by providing the reader with a rich source of worked
problems and examples. Alternatively, it may be used as a self-study guide to DSP, using the method
of learning by example. With either approach, this book has been written with the goal of providing
the reader with a broad range of problems having different levels of difficulty. In addition to
problems that may be considered drill, the reader will find more challenging problems that require
some creativity in their solution, as well as problems that explore practical applications such as
computing the payments on a home mortgage. When possible, a problem is worked in several
different ways, or alternative methods of solution are suggested.
The nine chapters in this book cover what is typically considered to be the core material for an
introductory course in DSP. The first chapter introduces the basics of digital signal processing, and
lays the foundation for the material in the following chapters. The topics covered in this chapter
include the description and characterization of discrete-type signals and systems, convolution, and
linear constant coefficient difference equations. The second chapter considers the represention of
discrete-time signals in the frequency domain. Specifically, we introduce the discrete-time Fourier
transform (DTFT), develop a number of DTFT properties, and see how the DTFT may be used to
solve difference equations and perform convolutions. Chapter 3 covers the important issues
associated with sampling continuous-time signals. Of primary importance in this chapter is the
sampling theorem, and the notion of aliasing. In Chapter 4, the z-transform is developed, which is
the discrete-time equivalent of the Laplace transform for continuous-time signals. Then, in Chapter
5, we look at the system function, which is the z-transform of the unit sample response of a linear
shift-invariant system, and introduce a number of different types of systems, such as allpass, linear
phase, and minimum phase filters, and feedback systems.
The next two chapters are concerned with the Discrete Fourier Transform (DFT). In Chapter 6, we
introduce the DFT, and develop a number of DFT properties. The key idea in this chapter is that
multiplying the DFTs of two sequences corresponds to circular convolution in the time domain.
Then, in Chapter 7, we develop a number of efficient algorithms for computing the DFT of a finitelength
sequence. These algorithms are referred to, generically, as fast Fourier transforms (FFTs).
Finally, the last two chapters consider the design and implementation of discrete-time systems. In
Chapter 8 we look at different ways to implement a linear shift-invariant discrete-time system, and
look at the sensitivity of these implementations to filter coefficient quantization. In addition, we
analyze the propagation of round-off noise in fixed-point implementations of these systems. Then, in
Chapter 9 we look at techniques for designing FIR and IIR linear shiftinvariant filters. Although the
primary focus is on the design of low-pass filters, techniques for designing other frequency selective
filters, such as high-pass, bandpass, and bandstop filters are also considered.


18-06-2008, 12:03 PM
Merciiiiiiiiii bcp mon frre LARBI
You are always the Best
thank's man

serie schaum