% % Filename: example2.m % % Description: M-file for demonstrating periodicity of discrete- % time signals. % clear; clf; % clear memory and figure n = 0:20; x = sin(5*n + 0.1); subplot(2,2,1); stem(n,x,'filled'); grid; xlabel('n'); ylabel('x[n]=sin(5n+0.1)'); title('Aperiodic Discrete-Time Signal'); x = cos(10*pi*n/6 - 0.22); subplot(2,2,2); stem(n,x,'filled'); grid; xlabel('n'); ylabel('x[n]=cos(10*pi*n/6-0.22'); title('Periodic Discrete-Time Signal'); t = 0:0.01:20; % continuous-time values xcon = sin(2*t); % continuous-time signal T = 0.5; % sample interval (time) n = 0/T:20/T; % discrete-time values (from t=nT) xdisc = sin(n); % discrete-time signal subplot(2,1,2); % plot both signals on continous-time axis plot(t,xcon); % use t = nT for discrete-time signal hold on; stem(n*T, xdisc, 'filled'); hold off; grid; xlabel('tMATLAB Plot Generated:'); ylabel('x[n],x(t)'); title('Periodic x(t)=sin(2t) Sampled at T=0.5sec to get Aperiodic x[n]=sin(n)');