Project - Data Handling and Interpolation

% Program reads data from excel sheet and executes interpolation for the given range of data

A= xlsread('VI.xlsx')

V= A(:,1); % Reading and storing the values of voltage in vector V.

I= A(:,2); % Reading and storing the values of current in vector I.

plot(V,I,'*'); % plotting V vs I

hold on;

Vx=-17.3:0.1:0.9; % interpolation range

Ix=spline(V,I,Vx);

plot(Vx,Ix,'-g'); % plotting interpolated Vx Vs Ix curve.

grid;

xlabel(' Voltage V'); % labelling the plot

ylabel('Current I');

title('V-I Curve');

legend('Given data','Interpolated data');

hold off;

% Computing the current from given values of voltages and storing them in a text file

VV=[-17.2 -17.1 -13.8 -13.5 -13.0 -12.5 -11 -9 -5.76 -6 -1 0.11 0.25 0.5 0.61]; % loading V as per sheet

II=pchip(V,I,VV); % current calculation using pchip interpolation

B=[VV;II];

name='Current Calulation'; % title of text file

v='Voltage(Volt)'; % labeling the coloumns of text file

i='Current(mAmp)';

fid = fopen('Week4project.txt','w'); % creating text file

fprintf(fid,'%s\n\n',name);

fprintf(fid,'%s %s\n',v,i);

fprintf(fid,'%f %f\n',B);

fclose(fid);

figure(2)

plot(VV,II,'b'); grid;

xlabel(' Voltage(Volt)'); % labelling the plot

ylabel('Current(mAmp)');

title('Given Voltage vs Calculated current');