% MATLAB Tutorials - 16.01 / 16.02 Unified Engineering - MIT Fall 2007
% Instructor: Violeta Ivanova, violeta@mit.edu
% MIT Office of Educational Innovation & Technology
% Faculty: Karen Willcox, kwillcox@mit.edu, MIT Aeronautics & Astronautics

% 1. IMPORT TIME AND MEASURED RESPONSE DATA
% HINT: Use the MATLAB Import Wizard to import time and response data
% from the file QUANSER.DAT. Then use function WHO to confirm that you have
% created two new variables in the MATLAB workspace: time, response.

% 2. PLOT THE IMPORTED DATA AS RESPONSE V. TIME
% Write code here:
plot(time, response, 'rx');

% 3. FIT A COMPLEX EXPONENTIAL MODEL TO THE DATA
% HINT: Define a new function of time in a separate m-file EXPMODEL.M, 
% which uses the parameters below. Then try here different values for them 
% until graphically your model fits the data. 

% STEP A: Try values for model parameters
% Uncomment and assign values to parameters:
A = 20     
alpha = -0.1    
phi = 1
omega = -3 

% STEP B: Compute model fit
% HINT: Compute model response Y as a function of TIME
% Write code here:

y = expmodel(time, A, alpha, omega, phi);

% STEP C: Add model fit to the plot of response v. time
% Write code here: 

hold on
plot (time, y);
hold off

% STEP D: Graphically evaluate the model fit
% HINT: If the model is way off repeat steps A, B, and C.

% 4. CUSTOMIZE PLOT AND SAVE FIGURE
% HINT: Use the Figure Property Editor