OPERATIONS ON DISCRETE TIME SEQUENCES

The following matlab code performs time scaling, shifting and reversal

clc;

clear;

s=input('Enter length of sequence');

l=input('Enter lower limit');

u=l+s-1;

j=1;

%for loop for a random sequence

n=[l:u];

for i=l:1:u

xn(j)=ceil(5*rand+2);

j=j+1;

end

subplot(3,1,1);

stem(n,xn);

grid on;

xlabel(n); ylabel(x[n]);

%plot x[an+k]

a=input('Enter the scaling factor');

k=input('Enter shifting factor');

%k>0advance and k0

l=l-k;u=u-k;

n=[l:u];

end

if k1 - compression

if abs(a)~=1 && abs(a)>1

for i=1:1:length(n)

k=n(i)/a;

if k-fix(k) == 0

n1(j)=k;

xn1(j)=xn(i);

disp(k);

j=j+1;

end

end

if a

%abs(a)

PLOT 1 :

PLOT 2: x [-0.5n 1]

PLOT 2 :

OPERATIONS ON CONTINOUS TIME SIGNALS

The following matlab code does time scaling and shifting on CT signals.

clc;

clear all;

close all;

%plot x(at + k)

l=input('Enter lower bound of the plot');

u=input('ENter upper bound');

syms t;

x=input('Enter the function');

f=inline(x);

disp(f);

t=[l:0.01:u];

a=input('Enter the scaling factor');

k=input('Enter the shifting factor');

xt=f(t);

subplot(3,1,1);

plot(t,xt);

;ylabel('x(t)');

axis([-2*pi 2*pi -1 1]);

title('CT signal');

grid on;

subplot(3,1,2);

plot(t+k,xt);

ylabel('x(t+k)')

axis([-2*pi 2*pi -1 1]) ;

title('Shifted signal');

grid on;

subplot(3,1,3);

if a

PLOT 1:

X(t) = sin(t)

X(-2t ) is plotted.

PLOT 2:

x(-0.5t + 1) , where x(t)=t;

PLOT 2: