Digital filters and signal processing in electronic engineering : theory, applications, architecture, code

247 Pages·1998·10.9 MB·English

by  S. M. Bozic and R. J. Chance.

Digital Filters and Signal Processing
in Electronic Engineering
Theory, Applications, Architecture, Code
"Talking of education, people have now a-days" (said he) "got a strange opinion
that everything shouldbe taught bylectures. Now,1cannot seethat lectures can
do somuch goodas reading the booksfrom which the lectures are taken. I know
nothing that can be best taught by lectures, except where experiments are to be
shewn. You mayteach chymestrybylectures- Youmight teach making ofshoes
bylectures!"
JamesBoswell: Life ofSamuelJohnson, 1766 (1709-1784)
"Mathematics possesses not only truth, but supreme beauty - a beauty cold and
austerelikethat ofsculpture,and capableofsternperfection, suchas onlygreat art
canshow.
Bertrand Russellin ThePrinciplesofMathematics (1872-1970)
About the Authors
S.M. Bozic graduated in communications and electronics at Belgrade University
and subsequently worked in research and development in the communications
industry, in Germany and the UK for 11 years. He obtained his PhD at the
University ofAston (UK) and then joined the School ofElectronic and Electrical
Engineering at the University ofBirmingham (UK), as a lecturer. His main areas
of interest started in communications and electronics, but for some years, his
research and teaching activity has specialised indiscrete-time and digital circuits,
leading to digital filters, digital control and particularly Kalman filtering. Dr.
Bozic has published a number of research papers on digital systems, as well as
books, including Digital and Kalmanfiltering, (Arnold 1979, 1994), Electronic
and switching circuits (co-author, Arnold 1975) He also contributed to Digital
signalprocessing, (lEE Control Engineering, UniversityofSussex 1982).
R.J.Chance graduated firstly in medical biochemistry, with a further degree in
electronics engineering at the University ofBirmingham, UK. He has specialized
inmicroprocessors since 1976andjoined the Microprocessor Systems Laboratory
at Birmingham University when it was formed in 1980. As manager of this
facility, his remit was to assist all departments in Birmingham University to
introduce and use microprocessors intheir teaching and research activities. In the
course ofthis, he was responsible for the design ofmore than 40 microprocessor
based systems, applied to just about everything between biochemistry and
transportation. During 1982, Jim Chance started to specialise in digital signal
processors, particularly the design ofdevelopment environments for DSP system
testing. Around 30 published papers describe this and other work. The TMS320
assembler and simulator used in this book were written by RJc. In 1990, he
joined the School of Electronic and Electrical Engineering at Birmingham as a
lecturer, where he has been responsible for second and third year courses on
microprocessors, as well as industrial research and development in collaboration
with the railway traction, nautical navigation and telecommunications industries.
R.J.Chance isamember ofthe British Computer Society.
Digital Filters and Signal Processing
in Electronic Engineering
Theory, Applications, Architecture, Code
S.M. BOZIC
and
R.J. CHANCE
School ofElectrical and Electronic Engineering
University ofBirmingham
Horwood Publishing
Chichester
First published in 1998by
HORWOOD PUBLISHING LIMITED
International Publishers
Call House, Westergate, Chichester, West Sussex, P020 6QL
England
COPYRIGHTNOTICE
All Rights Reserved. No part of this publication may be reproduced, stored in a
retrieval system, or transmitted, in any form or by any means, electronic,
mechanical, photocopying, recording, or otherwise, without the permission of
HorwoodPublishing, International Publishers, ColIHouse,Westergate, Chichester,
WestSussex,England
© S.M.Bozicand R.J. Chance
British Library Cataloguing in Publication Data
AcataloguerecordofthisbookisavailablefromtheBritishLibrary
ISBN 1-898563-58-6
Printed in GreatBritainbyMartins Printing Group,Bodmin, Cornwall
Preface
The term Digital Signal Processing (DSP) is normally used to describe
signal processing in discrete time, leading to difference equations for the case
considered. However, the execution ofthese equations as algorithms on a Digital
Signal Processor is also called Digital Signal Processing, even though the
expertise demanded ofthe engineer is utterly different from that required for
the mathematical basis. Until recently, such implementations were mostly
simulations of a process described by an algorithm. However, present day
microprocessors of specialised design - DSP devices- are capable ofperforming
DSPoperations inrealtime.
A special feature ofthis book is that, after deriving the equations, they are
implemented as algorithms, not only in Matlab, but, through pseudo-code, right
up to working DSP-based software whose speed and performance can be directly
demonstrated. We anticipate that this book will give the reader the confidence to
perform the same type of development process to suit his own particular work.
The construction of state-ofthe-art engineering products invariably involves the
design of working machinery, based on fundamentals which can only be
expressed mathematically. However, at the sharp end of the research and
development business, one needs to have a physical model ofthe working system
in mind at all times, in order to be able to make modifications in the field with
confidence. This is why the reader will find unique non-mathematical
conceptual models of several important but perplexing basic ideas, such as the
FFTandmultirate filters, to complementthe mathematicaltheory.
Chapter I introduces the general signal processing scheme, from the sampling
processto fundamental results inthe form ofthe Discrete-time Fourier Transform
(DtFT). The reader proceeds through DSP signal descriptions, such as difference
equations, transfer functions and convolution to understand concepts of
multirateDSP.
Chapter 2 Describes how numbers are stored and manipulated within the digital
signal processor, which is so often quite different from methods used in
conventional computers. This material is independent of any manufacturer's
processorand applicable to any DSP device.
Preface
VI
Chapter 3 gives a briefinsight into the architectures of8 OSP devices from four
manufacturers in order to demonstrate special hardware features which are
architecture dependent. This should put the reader in a good position to use and
make a comparison betweendifferentcurrentand future DSP devices.
Chapter 4 develops the OFT and itsuse inconvolution andcorrelation and arapid
method forcarrying out OFT computations, the Fast Fourier Transform (FFT).
The Goertzel algorithm and Chirp-z transform are introduced. All these start
as mathematical concepts and in Chapter 4 are carried through to programs
running on the Matlabsystem.
Chapter 5 explains the FFT, which is so very well known for its ability to
separate a waveform into its component sine-waves, as a physical model. This
can beusedto"intuit"the effects ofall sortsofmanipulations ofthe algorithm, in
support ofthe mathematical rigor ofchapter 4. Assembler languageprogramsfor
bothFFTand Goertzel are constructed from first principles and their performance
given.
Chapter 6 Explains the properties and design of Finite Impulse Response
(FIR) filters by Fourier series and frequency response sampling, with examples
includingamultirate filterdesign. Algorithmsaredemonstrated, usingMatlaband
a multirate filter scheme is carried through to the OSP assembler languagestage.
This includesa non-mathematical construction ofcoefficient ordering and other
multirate filter principles.
Chapter 7 covers IIR filter structures and design by impulse invariance and
bilinear transform methods. There is also consideration of the effects of
quantization noise and scaling. Some of the effects of the latter on practical
design can be seen in an assembler language IIR example, constructed, as usual
fromtheequations, viaMatlab andpseudocode.
Chapter 8 concludes the book with some other important OSP topics. These
include deconvolution and system identification, homomorphic deconvolution,
control and adaptive filtering. The reader is taken through the whole software
development process for a control system and an adaptive filter, whose
performanceisshown.
Very few individuals are able to master the whole ofthe progression from
equation to working device, in any field, but especially if it is as new as digital
signal processing. The intention ofthis book is to remedy this difficulty for up
and-coming young engineers, working with all manner of digital filters, using
Fourier,thinking about applyingspecialisedOSPdevices, which can beapplied in
somanyengineering areas.
Preface vii
We hope that students using this book will no longer feel that they need to
create programs by slavishly copying existing listings and attempting to adapt
them to the immediate purpose without full comprehension. We hope that the
student will understand and build on the examples between these covers, at all
stages, from mathematical foundation to operational machine. This might become
a lifelongandprofitable habit.
S.M.Bozic andR.J.Chance
Birmingham,UK,
September 1998.
ACADEMIC REQUIREMENTS
First and secondyear mathsand introductory knowledgeofmicroprocessors and
the C language.
INTERNET SOFTWARE
The TMS320C25 assembler, simulator and DSP source listings in this book can
befoundonthe internetwebsite HTTP://www.eee.bham.ac.ukldspbook.
Contents
Preface v
1 Basic concepts and analytical tools 1
1.0 Introduction I
1.1 Samplingand signal reconstruction 2
1.2 ADC quantization noise 4
1.3 The Z-transform 5
1.4 InverseZ-transform 8
1.5 DSP Signal description 10
1.6 Multiratedigital signal processing 13
1.6.1Decimation 14
1.6.2 Interpolation 15
1.6.3Combined decimation and interpolation 18
Appendix 1.1:Frequencyspectrum, form 1.. 20
Appendix 1.2:Frequency spectrum form 2 20
Appendix 1.3:Dirac function; Fourierpairs 22
Appendix 1.4:Convolutionequation derivation 23
2The fundamental features ofaDSP 25
2.0 Introduction 25
2.1 DSP historyand performance 26
2.2 Number representation in DSPs 28
2.2.1 Integernumber representation 28
2.2.2 Sign extension 30
2.2.3 Fractional representation 31
2.2.4 Floatingpoint representation 32
2.3 The multiply-accumulate operation 33
2.4 Fundamental DSP addressing modes 34
2.4.1 Normal indirectaddressing modes 35
2.5 Special DSP indirectaddressing modes 35
2.5.1 Bit-reverse(reverse carry) addressing 36
2.5.2 Circularaddressing 36
2.6 Special DSP iteration schemes 39
2.6.1 Single instruction repeat., 39
2.6.2 Multiple instruction repeat., 40
Contents IX
2.6.3 The delayed branch 41
2.7 Summary 42
Appendix2.1: TMS320C251C50 floating pointroutines 43
3 ThePracticalDSP devices 45
3.0 Introduction 45
3.1 Overview ofcommercial DSPs 46
3.1.1 On-chip stack 47
3.1.2 Hostport 48
3.1.3 Interrupts 48
3.1.4 Synchronous serial ports 48
3.2 MotorolaDSP56000 & DSP96000 49
3.2.1 Arithmetic on the DSP56000 49
3.2.2 DSP56000 addressing modes 50
3.2.3 MotorolaDSP96000 52
3.2.4 DSP56000 and DSP96000 Interrupts 52
3.3 TMS320C25 and TMS320C50 53
3.3.1TMS320C251C50 programmer's model 53
3.3.2 Multiply-accumulate on the TMS320C25IC50 54
3.3.3C251C50 directaddressing 55
3.3.4C251C50 Interrupts 56
3.4 ADSP2100 and ADSP21020 56
3.4.1 ADSP2100 and ADSP21020 memory 56
3.4.2 MiscellaneousADSP2100 and ADSP21020 facilities 57
3.5 DSP32 and TMS320C30 58
3.5.1 Accessingthe DSP32 memory space 58
3.5.2 The TMS320C30 memory space 59
4DiscreteFourierTransform: properties, uses, and computations 61
4.0 Introduction 61
4.1 Discrete Fouriertransform (DFT) 61
4.2 Use ofthe DFT in convolution 66
4.3 Use ofthe DFT incorrelation 71
4.4 Calculation ofthe DFT :FFT algorithms 72
4.4.1 FFT algorithm, radix 2, decimation-in-frequency 75
4.5 The Goertzel algorithm 79
4.6 The ChirpZ-transform (CZT) 80
4.7 Spectral analysis with computers 83
4.7.1 FFT and Goertzel algorithm tests 83
4.7.2 High resolution narrowband spectral analysis 87
5DSP implementations ofFourierand Goertzel algorithms 89
5.0 Introduction 89