clc
clear
close all

fprintf('-------------------------------------------------------------------\n');
fprintf(' Reads the Fluke scope .csv file of one channel                    \n');
fprintf('-------------------------------------------------------------------\n');

prefix_in = input('Enter the file prefix (.csv) => ', 's');	
file_in_name = [prefix_in, '.csv'];		

file_in = fopen(file_in_name, 'r');									
for k=1:21
   i = 0;
   ch  = '0';
   while(ch ~= 10)
      ch  = fscanf(file_in, '%c', 1);
      if (ch ~= 10) 
         i = i+1;
         str(i) = ch;
     end;
   end;
   str = strrep(str,'"','');
   str = strrep(str,',',' ');
   %fprintf('%s',str)
   clear str
end;
for i=1:512
   t_in(i) = fscanf(file_in, '%f', 1);
   dum     = fscanf(file_in, '%c', 1);
   v_in(i) = fscanf(file_in, '%f', 1);
end;
fclose(file_in);

Ts = t_in(2) - t_in(1);
Fs = 1/Ts;
N = 500;
fn = Fs/N;

k  = [0:1:N-1];
n  = [0:1:N-1];

t  = k*Ts;
for i=1:N
   vt(i) = v_in(i);
end;

if (mod(N,2) == 0)
   f  = -Fs/2 + n*fn;
else
   f  = -Fs/2 + n*fn + fn/2;
end;
Vf = (1/N)*fftshift(fft(vt));

fprintf('sampling frequency   = %6.2f Hz \n', Fs);
fprintf('frequency resolution = %6.2f Hz \n', fn);
fprintf('sampling time        = %6.2f us \n', Ts*1e6);
fprintf('time interval        = %6.2f ms \n', t(N)*1000);
fprintf('number of points     = %6.0f \n', N);


figure(1)
plot(1000*t, vt, 'r')
axis([0 1000*t(N) -12 12])
xlabel('time in milli seconds')
ylabel('volts')

figure(2)
plot(f, abs(Vf), 'r')
grid on
axis([-Fs/8 Fs/8 0 4])
xlabel('frequency in Hz')
ylabel('|cn|')