BEIT, 6th Semester Digital Signal Processing : Introduction to MATLAB Ms. T. Samanta Lecturer Department of Information Technology BEIT, 6th Semester Books:  “Getting Started with MATLAB” - Rudra Pratap  “Digital Signal Processing ” - Sanjit K. Mitra.  “Digital Signal Processing-A Practitioner’s Approach” - Kaluri V. Rangarao - Ranjan K. Mallik BEIT, 6th Semester Introduction  MATLAB -> MATrix LABoratory  Built-in Functions -Computations -Graphics -External Interface -Optional Toolbox for Signal Processing, System analysis, Image Processing BEIT, 6th Semester How many windows? BEIT, 6th Semester MATLAB Windows  Command window: main window characterized by ‘>>’ command prompt.  Edit window: where programs are written and saved as ‘M-files’.  Graphics window: shows figures, alternately known as Figure window. BEIT, 6th Semester Command Window Figure Window Edit Window BEIT, 6th Semester Matlab Basics BEIT, 6th Semester MATLAB Basics: Variables  Variables: -Variables are assigned numerical values by typing the expression directly >> a = 1+2 press enter >> a = 3 >> a = 1+2; suppresses the output BEIT, 6th Semester Variables  several predefined variables i sqrt(-1) j sqrt(-1) pi 3.1416  >> y= 2*(1+4*j) >> y= 2.0000 + 8.0000i BEIT, 6th Semester Variables  Global Variables  Local Variables [...]... command:axis([xmin xmax ymin ymax]);  plot: 2D Plotting  stem(k,y ): for discrete-time signals this command is used  To plot more than one graph on the screen, subplot(m,n,p ): breaks the Figure window into an m-by-n matrix of small axes, selects the p-th sub-window for the current plot  grid : shows the underlying grid of axes BEIT, 6th Semester Example: Draw sine wave      t=-2*pi:0. 1:2 *pi;... B  Element by element operations: * , / , ^ etc a = [1 2 3], b = [2 2 4], =>do a.*b and a*b BEIT, 6th Semester Vectors BEIT, 6th Semester Few methods to create vector  LINSPACE(x1, x2 ): generates a row vector of 100 linearly equally spaced points between x1 and x2  LINSPACE(x1, x2, N ): generates N points between x1 and x2  LOGSPACE(d1, d2 ): generates a row vector of 50 logarithmically equally... time') ylabel(' > sin(t)') BEIT, 6th Semester Matlab Plot BEIT, 6th Semester Example: Discrete time signal      t=-2*pi:0. 5:2 *pi; y=1.5*sin(t); stem(t,y); xlabel(' > time') ylabel(' > sin(t)') BEIT, 6th Semester Matlab Plot BEIT, 6th Semester Example: Draw unit step and delayed unit step functions           n=input('enter value of n') t= 0:1 :n-1; y1=ones(1,n); %unit step y2=[zeros(1,4)... equally spaced points between decades 10^d1 and 10^d2  a = 0:2 :1 0 generates a row vector of 6 equally spaced points between 0 and 10 BEIT, 6th Semester Waveform representation BEIT, 6th Semester 2D Plotting creates linear continuous plots of vectors and matrices;  plot(t,y ): plots the vector t on the x-axis versus vector y on the y-axis  To label your axes and give the plot a title, type xlabel('time.. .MATLAB Basics:  Arithmetic operators: + addition, - subtraction, * multiplication, /division, ^ power operator, ' transpose BEIT, 6th Semester Matrices  Matrices : Basic building block  Elements are entered row-wise >> v = [1 3 5 7] creates a 1x4 vector >> M = [1 2 4; 3 6 8] creates a 2x3 matrix >> M(i,j) => accesses the element... Run  a =[10 10 10]; d = [3 3 3]; Another m file to access  mod(a,d); above function BEIT, 6th Semester Loops, flows: for m= 1:1 0:1 00 num = 1/(m + 1) end %i is incremented by 10 from 1 to 100 I = 6; j = 21 if I > 5 k = I; elseif (i>1) & (j == 20) k = 5*I + j else k = 1; end %if statement BEIT, 6th Semester Recapitulate BEIT, 6th Semester Few in-built Matlab functions sin() cos() log() asin() acos()... and jth column BEIT, 6th Semester Basics Matrices  Special Matrices null matrix: nxm matrix of zeros: nxm matrix of ones: nxn identity matrix: M M M M = = = = []; zeros(n,m); ones(n,m); eye(n); Try these Matrices [eye(2);zeros(2)],[eye(2);zeros(3)], [eye(2),ones(2,3)] BEIT, 6th Semester Matrix Operations  Matrix operations: A+B is valid if A and B are of same size A*B is valid if A’s number of columns... variable] = function_name (input variable)  File name should be exactly same as function name BEIT, 6th Semester Example : user defined function Assignment is the method of giving a value to a variable You have already seen this in the interactive mode We write x=a to give the value of a to the value of x Here is a short program illustrating the use of assignment function r=mod(a,d)  %If a and d are integers,... Matlab command window, press enter This will display the function definition Study the definition of each function BEIT, 6th Semester Practice 1>Draw a straight line satisfying the equation: y = 3*x + 10 2> Create matrices with zeros, eye and ones 3>Draw a circle with radius unity (use cosθ for x axis, sinθ for y axis) 4>Draw a cosine wave with frequency 10kHz Use both ‘plot’ and ‘stem’ functions to. .. stem(t,y1,'filled');ylabel('amplitude'); xlabel('n ->');ylabel('amplitude'); subplot(2,1,2); stem(t,y2,'filled'); xlabel('n ->');ylabel('amplitude'); BEIT, 6th Semester Matlab Plot BEIT, 6th Semester Functions BEIT, 6th Semester Scripts and Functions  Script files are ‘M-files’ with some valid MATLAB commands  Generally work on global variables present in the workspace  Results obtained after executing script files are left in . Semester Digital Signal Processing : Introduction to MATLAB Ms. T. Samanta Lecturer Department of Information Technology BEIT, 6th Semester Books:  “Getting Started with MATLAB - Rudra Pratap  Digital. Pratap  Digital Signal Processing ” - Sanjit K. Mitra.  Digital Signal Processing- A Practitioner’s Approach” - Kaluri V. Rangarao - Ranjan K. Mallik BEIT, 6th Semester Introduction  MATLAB ->. 6th Semester MATLAB Basics:  Arithmetic operators: + addition, - subtraction, * multiplication, /division, ^ power operator, ' transpose BEIT, 6th Semester Matrices  Matrices : Basic building