function ts_tutorial_v1

clear all
close all

sr1 = 1000;
sr2 = 128;
tmax = 1;
iopt = 1;


 i_wf = menu('Choose waveform:','Single 8 Hz', '1 and 16 Hz','1 and 20 Hz')

% Define the input signal (sum of 3 sine curves)

if i_wf == 1;
  nf =1 ; a = [1,0.0,0.0]; ph = [0., 0.,0.,]; f = [8,10,64];
end

if i_wf == 2;
  nf = 2; a = [1,0.5,0.0]; ph = [0., 0.,0.,]; f = [1,16,64];
end

if i_wf == 3;
  nf = 2; a = [1,0.5,0.0]; ph = [0., 0.,0.,]; f = [1,20,64];
end

w = 2*pi*f;

% Amplifier and ADC characteristics
vmax = 2;
vmin = -2;
gain = 1;

vmax_plot=[vmax,vmax];
vmin_plot=[vmin,vmin];
t_plot = [0,tmax]

nbit = 2;

while iopt < 8;


dv   = (vmax-vmin)/nbit; 

t1=[0.0:1/sr1:tmax];n1 = length(t1)



for it=1:n1
    v1(it)= a(1)*sin(w(1)*t1(it)+ph(1))+a(2)*sin(w(2)*t1(it)+ph(2))+a(3)*sin(w(3)*t1(it)+ph(3));
end

t2=[0.0:1/sr2:tmax];n2 = length(t2)
for it=1:n2
    v2(it)= (a(1)*sin(w(1)*t2(it)+ph(1))+a(2)*sin(w(2)*t2(it)+ph(2))+a(3)*sin(w(3)*t2(it)+ph(3)))*gain;
    
    ndig = fix(v2(it)/dv);
    v2(it) = ndig*dv;
    
    if v2(it) >= vmax;  v2(it) = vmax; end
    if v2(it) <= vmin;  v2(it) = vmin; end
end





subplot(2,1,1)

plot(t1,v1);
axis([0,tmax,vmin*1.3,vmax*1.3])
%title(['True signal  :  f = ',num2str(f(1)),' Hz']);

if nf == 1;
    title(['True signal  :  f_1=',num2str(f(1)),' Hz'])
end
if nf == 2;
    title(['True signal  :  f_1=',num2str(f(1)),' Hz; f_2=',num2str(f(2)),'Hz'])
end
    
ylabel('signal (V)')


subplot(2,1,2)
plot(t2,v2,'.-')
title('Recorded data')
title(['Recorded signal  :  Gain = ',num2str(gain),';  Sample rate = ', num2str(sr2),' Hz;  Digitization level = ', num2str(nbit+1)])


xlabel('time(s)')
ylabel('signal (V)')
hold on
plot(t_plot,vmax_plot,'r');
plot(t_plot,vmin_plot,'r');
axis([0,tmax,vmin*1.3,vmax*1.3])

for idig = 0:nbit
    digplot = [(idig-nbit/2)*dv, (idig-nbit/2)*dv]
    tplot =[0,tmax]
    plot(tplot,digplot,':')
end




hold off


  iopt = menu('Change paramters:','SR x2','SR x 0.5','bit x 2','bit x 0.5','gain + 0.1','gain - 0.1', 'phase +45 deg','quit')
    
    if iopt ==1; sr2 = sr2*2; end;
    if iopt ==2; sr2 = sr2*0.5; end;
    if iopt ==3; nbit = nbit*2; end;
    if iopt ==4; nbit = nbit/2; end;
    if iopt ==5; gain = gain+0.1; end;
    if iopt ==6; gain = gain-0.1; end;
    if iopt ==7; ph(1) = ph(1)+pi/4; end;
    
    
    clear v2; t2;

end

print -djpeg100 tsfig.jpg


end