% 6.003: Signals and Systems - Spring '97
% S97Less5.M	Lesson 5 of MATLAB MiniCourse Demonstration script 
% 		by Pat Kreidl

%%%%% Illustrative Example -- Parallel RLC Circuit
!clear
type 5.txt
pause     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
!clear
type problem.txt
pause     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

echo on
% Outline of Solution:	We will first demonstrate how to create a 
%			specialized function and script (using M-files) 
%			involving the already familiar commands given in the 
%			Basic Note.  This solution method requires that we 
%			first obtain the analytical solution of the step 
%			response in our circuit.
%
%			Then, we will make use of MATLAB's Help features to 
%			learn about the currently unfamiliar, yet very powerful
%			commands given in the Advanced Note.  We will  
%			create another script (M-file) that uses these advanced
%			commands, and see that we will have saved ourselves
%			a significant amount of work because we will not 
%			require grinding through the analytical solution!
pause     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
!clear
%%%%% Basic Solution
%
%      The approach we take here is to define a MATLAB function which takes as 
% inputs values for R, L, C, and T and gives the corresponding step response 
% as the output.  This function we will call    rlcstep.m   The equations in
% this file come from the analytical solution (consult the Lesson 5 
% supplementary handout).
%      Then, we write a MATLAB script   rlc1.m    which calls on function   
% rlcstep.m     for each of the three cases, and includes the necessary plot 
% commands.
%
% NOTE:  While studying this solution, we will also be introduced to MATLAB's
%        C language-based "control flow" operations (e.g., if-elseif-else 
%	 conditional statements, while loops, for loops, etc.). 
pause     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
!clear
type rlcstep.m		%View the MATLAB function M-file
pause     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%NOTICE:  1) Function header line (distinguishes function from script)
%         2) Help section (the many rows of commented lines at top of file)
%         3) Use of an if-elseif-else statement
%         4) Included in-line comments for future reference 
pause     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
!clear
			%The comments section after the function header is the
help rlcstep		%help information!			
pause     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
!clear
rlc1			%Run MATLAB script file
pause     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
clear
!clear
%%%%% Advanced Solution
%
%      The approach we take here is to rely on the powerful functions given in 
%      the advanced note of the problem statement.  The first step is to use 
%      MATLAB's Help features to learn exactly how these functions work.  Then,
%      we write a MATLAB script   rlc2.m    which calls on these functions for 
%      each of the three cases.  These functions will allow us to determine 
%      the form of the step response, in addition to plotting them, without 
%      relying on the analytical solutions!
pause     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
!clear
help residue		%Learn about function    residue
pause     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
!clear
help step		%Learn about function    step
pause     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
!clear
rlc2			%Run MATLAB script file 
pause     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

echo off
close
clear