%=================================================================
% Name：two-sided exponential signal
% This program is used to plot the curves of two-sided exponential
% signals.
%=================================================================
t=-5:0.01:5;
a1=input('輸入最大常數a=');
a2=input('輸入中等數值的常數a=') ;
a3=input('輸入最小常數a=');
x1=exp(-a1*abs(t));
x2=exp(-a2*abs(t));
x3=exp(-a3*abs(t));
subplot(3,1,1);
plot(t,x1);
axis([-5,5,0,1.2]);
grid on;title('The two-sided exponential signal f=exp(-abs(a*t))')
subplot(3,1,2);
plot(t,x2);
axis([-5,5,0,1.2]);
grid on;
subplot(3,1,3);
plot(t,x3);
axis([-5,5,0,1.2]);
grid on;xlabel('time t')
%================================================================