Instructor l l l Zhang Yu Qiang Email

Instructor l l l Zhang Yu. Qiang E-mail: E-mail ya_zyq@yau. edu. cn Office Phone: Phone 0911 -2331506

Textbook l S. K. Mitra, Digital Signal Processing – A Computer. Based Approach, Approach Fourth Ed. , Mc. Graw-Hill, 2012 http: //www. mhhe. com/engcs/electrical/mitra/

Reference

Reference

Matlab Reference l William J. Palm III, Introduction to Matlab 6 for Engineers, Engineers Mc. Graw-Hill, 2001 http: //www. mhhe. com/engcs/general/palm/

Requirements l knowledge of linear algebra and calculus l Signals and systems l Basic Matlab programming skills

Content l l l l Introduce Discrete-Time Signals and systems Discrete-Time signals and systems in the frequency domain Finite-length discrete transforms Fast Fourier Transform (FFT) Digital filter structure IIR Digital Filter Design FIR Digital Filter Design

Grading Policy l Homework – 10% l Experiment– 20% l Midterm Exam - 20% l Final Exam - 50 %

1 绪论 Preface

Preface l What is signal? u A signal is a function of independent variables such as time, distance, position, temperature, pressure and so on.

Preface l What is signal? u Signals play an important role in our daily life. Examples of signals that we encounter frequency: Speech and music signals represent air pressure as a function of time at a point in space. p A black-and-white picture is a representation of light intensity as a function of two spatial coordinates. p ……. p

Preface l Why discuss the signal? u The signal carries information. The objective of signal processing is to extract useful information carried by the signal. u The method of information extraction depends on the type of signal and the nature of information being carried by the signal. u

Preface l How do we obtain the desired signal ? u Most signals we encounter are generated by natural means. A signal can also be generated synthetically or by computer simulation. u

Preface l Examples of typical signals A typical electrocardiography (ECG, 心电图) trace

Preface One cycle of an ECG waveform

Preface The electrical activity of the heart is represented by the ECG signal. In practice, there are various types of externally produced artifacts that appear in the ECG signal. Unless these interferences are removed, it is difficult for a physician to make a correct diagnosis. p

Preface l Examples of typical signals u Musical p. The sound signal electronic synthesizer is an example of the use of modern signal processing techniques.

Preface l Examples of typical signals u Musical p. The sound signal electronic synthesizer is an example of the use of modern signal processing techniques.

Preface u Time Series

Preface u Time Series In many cases, the signals of interest are naturally discrete function of the independent variables. Often such signals are of finite duration. There are many reasons for analyzing a particular time series. p

Preface u Images

Preface p. The basic problems in image processing are image signal representation and modeling, enhancement, restoration, reconstruction from projections, analysis, and coding.

Preface l How is the signal processing done? u Acquisition (获取） u Analysis（分析） u Transformation（变换） u Synthesis（综合） u Estimate （估值） u Recognition （识别）

Preface l How is the signal processing done? The method of information extraction depends on the type of signal and the nature of information being carried by the signal. u Signal processing is concerned with the mathematical representation of the signal and the algorithmic operation carried out on it to extract the information present. u Signal processing may be carried out in time-domain or in a transformed domain. u

Preface l How Digital Signal Processing? p Circuits p General Computer p Single Chip Computer p DSP Chip

Preface l How Digital Signal Processing? u Various types of signal processing operations are employed in practice. u The desired operations are implemented by a combination of some elementary operations.

Preface u Simple time-domain operations –The three most basic time-domain signal operations are scaling, delay, and addition. –Another elementary operation is the product of two signals. –Two other elementary operations are integration and differentiation.

Preface u Filtering –One of the most widely used complex signal processing operations is filtering, whose main objective is to alter the spectrum according to some given specifications.

Preface u Multiplexing(复用） 用） and demultiplexing（解复

Preface

Preface u Signal –An generation equally important part of signal processing is synthetic signal generation.

Preface l Why Digital Signal Processing? p Easy adjustment p Less sensitive to tolerances of component values p Reproduced easily It has been possible to integrate highly sophisticated and complex digital signal processing systems on a single chip. p Realization of certain characteristics not possible with analog implementation. p

Preface l Why Digital Signal Processing? Digital signal processing is also associated with some disadvantages: u p Increased system complexity p Limited range of frequencies available for processing p Active devices p finite precision

Preface l Typical Digital Signal Processing Applications u Sound – – – recording applications Compressors and limiters Expanders noise gates Equalizers and filters Noise reduction system Delay and reverberation(回声） systems Special effects

Preface l Typical Digital Signal Processing Applications u Musical – – sound synthesis Wavetable synthesis Spectral modeling synthesis Nonlinear synthesis Physical modeling synthesis

DSP Solution

Programmable switch

Mobile phone

The handset is not only used for voice communication

ADSL （Asymmetric Digital Subscriber Line)

Software radio LNA BPF Local oscillator ADC DSP audio Digital video

Digital Camera

Digital Camera

HDTV (High Definition TV)

PDP (Plasma Display)TV

Home Theater

Watchman

Simulator of airplane

GPS(Global Position System)

Radar/Sonar

Cruise missile

Smart bomb from F 117

Pattern recognization

Fingerprint distinguish