EE342.01: MATLAB M-FILE FOR PLOTTING DTFT AND DFT SPECTRA

%
% Filename: example13.m
%
% Description: m-file that plots the DTFT and DFT spectra versus
%              discrete-time frequency
%

clear;                              % clear matlab memory

W = 0:0.001:2*pi;                   % define DT frequencies
X = sin(1.5*W).*exp(-j*W)./sin(W/2);% define DTFT X(W)

k=0:2;                              % define DFT frequency sample numbers
Wk=k*2*pi/3;                        % define DFT frequencies
Xk=[3 0 0];                         % define DFT Xk

subplot(2,1,1);                     % plot magnitude spectra
plot(W,abs(X));
hold;
stem(Wk,abs(Xk),'filled');
hold;
legend('|X(\Omega)|', '|X_k|');
xlabel('\Omega ');
ylabel('|X|');
title('Magnitude Spectra of DTFT X(\Omega) and DFT X_k for x[n]=p_{3}[n-1]');

subplot(2,1,2);                     % plot phase spectra
plot(W,angle(X)*180/pi);
hold;
stem(Wk,angle(Xk)*180/pi,'filled');
hold;
legend('{\angle X(\Omega)}', '{\angle X_k}');
xlabel('\Omega ');
ylabel('Angle(X) ');
title('Phase Spectra of DTFT X(\Omega) and DFT X_k for x[n]=p_{3}[n-1]');