% Analog SignalDt = 0.00005;t = -0.005:Dt:0.005;xa = exp(-1000*abs(t));%% Continuous-time Fourier TransformWmax = 2*pi*2000;K = 500; k = 0:1:K;W = k*Wmax/K;Xa = xa * exp(-j*t'*W) * Dt;Xa = real(Xa);W = [-fliplr(W), W(2:501)]; % Omega from -Wmax to WmaxXa = [fliplr(Xa), Xa(2:501)];subplot(1,1,1)subplot(2,1,1);plot(t*1000,xa);xlabel('t in msec.'); ylabel('xa(t)')title('Analog Signal')subplot(2,1,2);plot(W/(2*pi*1000),Xa*1000);xlabel('Frequency in KHz'); ylabel('Xa(jW)*1000')title('Continuous-time Fourier Transform')