introduction to matlab ppt

What is MATLAB? MATLAB stands for MATrix LABoratory.. Why Learn MATLAB and DSP? Digital Signal Processing DSP is the dominant technology today, and into the future, for small-signal

What is MATLAB?

 MATLAB stands for MATrix LABoratory

 MATLAB is a high-performance language for

technical computing.

 Math and computation

 Algorithm development (optimized for DSP)

 Data acquisition

 Modeling, simulation, and prototyping

 Data analysis, exploration, and visualization

 Scientific and engineering graphics

 Application development, including graphical

user interface building

Why Learn and Use MATLAB?

 Heavily used in EET/CET courses with DSP

content (CET311, EET350, EET453)

 Extensive built-in commands for scientific

and engineering mathematics

 Easy way to generate class demonstrations

and test examples

 Simple and intuitive programming for more

complex problems

 Standard and widely-used computational

environment with many features,

extensions, and links to other software.

Code

Composer

DSP Processor Platform

MATLAB + PC = DSP Processor!! (just less efficient)

Why Learn MATLAB (and DSP)?

 Digital Signal Processing (DSP) is the

dominant technology today, and into the

future, for small-signal electronic systems (i.e., just about everything)

 MATLAB has become one of the standard

design environments for DSP engineering

 Our students need to be literate and skilled

in this environment: knowledgeable in both

DSP and MATLAB

How Can I Learn MATLAB?

 Keep a copy of this presentation for

reference (available on my Web

Page)

 Get MATLAB loaded on your PC

 Read the “Getting Started” Users

Guide at the MathWorks web site

 Study some of the built-in help files

and demos

 Dive right in and use it!

This Presentation

 The MATLAB System

 The basics of MATLAB computation

 The basics of MATLAB graphing

 The basics of MATLAB programming

 Various course examples

 Mathematics

 Electronics

 Physics

 Signal Processing(*)

The MATLAB System

 MATLAB desktop

 Editor and debugger for MATLAB programs (“m-files”)

 Browsers for help, built-in and on-line documentation

 Extensive demos

 Elementary functions, like sum, sine, cosine, and complex arithmetic

 More sophisticated functions like matrix inverse, matrix eigenvalues, Bessel

functions, and fast Fourier transforms

 “Toolboxes” for special application areas such as Signal Processing

 “Programming in the small" to rapidly create quick and dirty throw-away

programs, or

 “Programming in the large" to create large and complex application programs

 2D and 3D plots

 Editing and annotation features

 A library that allows you to write C and Fortran programs that interact with

MATLAB

MATLAB Development Environment (Workspace)

MATLAB “Help” Utilities

 MATLAB is so rich that ‘help’ is essential

 Command name and syntax

 Command input/output parameters

MATLAB Function Library

(A Subset)

matlab\general - General purpose commands.

matlab\ops - Operators and special characters.

matlab\lang - Programming language constructs.

matlab\elmat - Elementary matrices and matrix manipulation matlab\elfun - Elementary math functions.

matlab\specfun - Specialized math functions.

matlab\matfun - Matrix functions - numerical linear algebra matlab\datafun - Data analysis and Fourier transforms.

matlab\polyfun - Interpolation and polynomials.

matlab\funfun - Function functions and ODE solvers.

matlab\sparfun - Sparse matrices.

matlab\scribe - Annotation and Plot Editing.

matlab\graph2d - Two dimensional graphs.

matlab\graph3d - Three dimensional graphs.

matlab\specgraph - Specialized graphs.

matlab\graphics - Handle Graphics.

Some Elementary Functions

Exponential

exp - Exponential.

expm1 - Compute exp(x)-1 accurately.

log - Natural logarithm.

log1p - Compute log(1+x) accurately.

log10 - Common (base 10) logarithm.

log2 - Base 2 logarithm and dissect floating point number pow2 - Base 2 power and scale floating point number.

realpow - Power that will error out on complex result.

reallog - Natural logarithm of real number.

realsqrt - Square root of number greater than or equal to zero sqrt - Square root.

nthroot - Real n-th root of real numbers.

nextpow2 - Next higher power of 2.

Some Specialized Functions

Number theoretic functions.

factor - Prime factors

isprime - True for prime numbers

primes - Generate list of prime numbers

gcd - Greatest common divisor

lcm - Least common multiple

rat - Rational approximation

rats - Rational output

perms - All possible permutations

nchoosek - All combinations of N elements taken K at a time factorial - Factorial function

The MATLAB Language

(M-file example)

function one_period(amp,freq,phase)

% ONE_PERIOD(AMP,FREQ,PHASE)

% This function plots one period of a sine wave with a given amplitude,

% frequency (in Hz), and phase ( in degrees).

T=1000/freq; % Compute the period in ms

t=0:T/100:T; % Define a 100 point ms time vector 1 period long

y=amp*sin(2*pi*t/T+phase*pi/180); % One period of the sine function

plot(t,y) % Plot the result and format the axes and title

xlabel('milliseconds')

ylabel('amplitude')

title(['One Period of a ',num2str(freq),' Hz Sinewave with

',num2str(phase), ' Degree phase'])

MATLAB Graphics:

2D Functions (Physics Example)

MATLAB Graphics:

2D Functions (Physics Example)

0 500 1000 1500 2000 2500 3000 3500

MATLAB Graphics:

3D Functions (DSP Example)

Basic MATLAB Computation:

Representation of Numbers and Variables

 MATLAB operates on n row by m column

Basic MATLAB Computation:

 Array, vector, and scalar operators

 Matrix and vector addition and

multiplication

 Element-by-element operations

 Variable statements and definitions

MATLAB Plotting and Graphics

 Rich set of commands for 2D and 3D

plotting of functions

 Command formatting and editing

 GUI formatting and editing

 Image display capabilities

 Animation capabilities

 Simple “copy and paste” for

publishing generated figures

MATLAB Plotting

Basic Commands

representation of digital signals)

 Etc, etc - See MATLAB help documentation

Basic Plotting - Examples

 Plot of sin(x) function

 Stem of sin(x) function

 Bar of sin(x) function

 Several sine functions with “hold”

 Several sine functions with “subplot”

Basic MATLAB Programming

 Scripts

 Functions

Structure of m-file Functions:

 Use of MATLAB functions as subroutines

 Use of “nargin” test and branch

Mathematics Example:

Polynomial Algebra (Convolution Operator)

 Polynomial products and factoring:

8 20

26 21

8 )

4 4

5 )(

2 3

4

33

25

=+

−

−

=+

z y

z y x

Electronic Circuits Example:

Mesh Analysis (Linear System)

Find the currents in

A*X = B

Electronic Circuits Example:

FET Operating Point

 Find the DC operating point of the following

D

S

GS D

V

V I

I

R V I

Electronic Circuits Example: FET Operating Point

 M-file: [Vgs_o,Id_o]=NFET_OP(Idss,Vp,Rs)

 [v,id]=nfet_op(12,-4,1200);

-4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0 0

0.002 0.004 0.006 0.008 0.01 0.012

50 m in front of goalposts whose

horizontal bar is 3.44 m above the

ground?

Physics Example:

Field Goal Problem

Solution: The general solution is the “trajectory equation.”

where y = height, x = distance from goal, v0 = take-off

speed, θ0 = take-off angle Given the take-off speed of

25 m/s, the problem requires the solutions for θ0 that

result in a minimum height of y = 3.44 m at a distance

of x = 50 m from the goal post Although an analytical

solution is possible, a graphical solution provides more

) ( cos 2

2 0

θ

θ

v

gx x

Physics Example:

Field Goal Problem

 MATLAB code for a graphical solution:

Physics Example:

MATLAB Results

Signal Processing Examples

 Fourier Synthesis and the Gibbs Phenomenon

][n 0 SINC 0n

π

,

5 , 3 , 1

) 2 sin(

2 ) (

s

n square

π π