clear all
% t=7*sin(48/180*pi)-cot(pi/17)+tan(72/180*pi)

% clc
% m=0:5:65
% f=(m*5280)/3600
% a={'mili/saatshi','futi/tsamshi'}
% a={a [m f]'}
% display(a)
% The sum of the original signal and the tree
% echoes is stored
% in a data file and then plotted.
t=0.0:0.1:10;
% s=zeros(size(t));
s(1:8)=[0 0.5 1 -0.5 0.75 0 -0.2 -0.1];
%%
% Generate three echoes by scaling and
% delaiing original signal.
%
echo_1=zeros(size(t));
echo_1(7:14)=0.5*s(1:8);
echo_2=zeros(size(t));
echo_2(14:21)=-0.3*s(1:8);
echo_3=zeros(size(t));
echo_3(21:28)=0.1*s(1:8);
%
% Add echoes to original signal giving new signal.
% Save time signal and new signal.
%  g=echo_1+echo_2+echo_3;
%  g(1:8)=g(1:8)+s;
g=[zeros(1,4*length(s)),s,0.5*s,0.3*s,0.1*s,zeros(1,length(t)-8*length(s))]
 
save echo3 t g;
% %
% plot new signal.
%
plot(t,g),...
title('signal with echo'),...
xlabel('t, seconds'),...
ylabel('g[k]'),...
grid