initial commit / add all books

1 files changed, 42 insertions, 0 deletions

diff --git a/830/CH4/EX4.2.07/DTFT_1.sce b/830/CH4/EX4.2.07/DTFT_1.sce
new file mode 100755
index 000000000..d807596c5
--- /dev/null
+++ b/830/CH4/EX4.2.07/DTFT_1.sce
@@ -0,0 +1,42 @@
+//Graphical//

+//Example 4.2.07 Sampling a Nonbandlimited Signal

+//Plotting Discrete Time Fourier Transform of

+//Discrete Time Signal x(nT)= exp(-A*T*abs(n))

+clear;

+clc;

+close;

+// Analog Signal

+A =1;    //Amplitude

+Dt = 0.005;

+t = -2:Dt:2;

+//Continuous Time Signal

+xa = exp(-A*abs(t));

+//Discrete Time Signal

+Fs =input('Enter the Sampling Frequency in Hertz');//Fs = 2Hz(or)20Hz

+Ts = 1/Fs; 

+n = -5:1:5;

+x = exp(-A*abs(n*Ts));

+// Discrete-time Signal

+//Discrete-time Fourier transform

+K = 500; 

+k = 0:1:K;

+w = %pi*k/K;

+X = x * exp(-sqrt(-1)*n'*w);

+X = real(X);

+w = [-mtlb_fliplr(w), w(2:K+1)]; // Omega from -w to w

+X = [mtlb_fliplr(X), X(2:K+1)];

+subplot(3,1,1);

+plot(t,xa );

+xlabel('t in msec.');

+ylabel('xa(t)')

+title('Analog Signal')

+subplot(3,1,2);

+plot2d3('gnn',n,x ) 

+xlabel('Discrete Time n.');

+ylabel('x(nT)')

+title('Discrete Signal');

+subplot(3,1,3);

+plot(w/(2*%pi),X );

+xlabel('Frequency in pi units');

+ylabel('X(w)')

+title('Discrete-time Fourier Transform')