%_____________________________________________________________________________
%%%%%%% Lesson 4: Plotting and Printing
%_____________________________________________________________________________
% 1) Generating and annotating simple plots of signals
% 2) Multiple plots on a page, multiple curves on a set of axes, and advanced
%    annotation of plots
% 3) Other useful types of plots
%_____________________________________________________________________________

t1 = linspace(0,2,11);		%Generate signal to be plotted
y1 = sin(2*pi*t1);		%Sinusoid with period 1 sec
plot(t1,y1)			%Open figure window and generate plot
				%NOTICE: plot does not appear sinusoidal...?
%______________________________________
t2 = linspace(0,2,51);		%Regenerate signal using more data points
y2 = sin(2*pi*t2 + pi/2);	%Sinusoid with period 1 sec shifted by 90 deg
figure(1);plot(t2,y2)		%Make figure window #1 active (rather than open
				%a second figure window) and plot
%______________________________________
				%Annotate plot in current figure window
title('Sinusoid y2(t) shifted by 90 deg')	%Add title
xlabel('t     (sec)')				%Label x-axis
ylabel('Amplitude')				%label y-axis
%______________________________________
figure(1)			%Make figure window #1 active
				%Can put many plots in same figure window
subplot(2,1,1)			%Generate 2x1 figure window, activate plot 1
plot(t1,y1)			%Generate plot 1
title('Sinusoid y1(t) with too few datapoints')	%Add title
xlabel('t     (sec)')				%Label x-axis
ylabel('Amplitude')				%label y-axis
subplot(2,1,2)			%Activate plot 2
plot(t2,y2)			%Generate plot 2
title('Sinusoid y2(t) shifted by 90 deg')	%Add title
xlabel('t     (sec)')				%Label x-axis
ylabel('Amplitude')				%label y-axis
%______________________________________
figure(1)			%Make figure window #1 active
plot(t1,y1,'y-',t2,y2,'r--')	%Generate plots using different line styles
title('Sinusoid y1(t) and y2(t)')		%Add title
xlabel('t     (sec)')				%Label x-axis
ylabel('Amplitude')				%label y-axis
%______________________________________
				%Can customize figure further
text(0.4,0.8,'y1(t)')		%Label curve for y1(t)
text(0.15,-0.5,'y2(t)')		%Label curve for y2(t)
axis([0,2,-1.2,1.2])		%Can change range of figure axes
grid on				%Can add a grid...
%______________________________________
grid off			%...and remove it if clutters the plot
%______________________________________
y3 = exp(-4*t2);		%Generate a third signal--decaying exponential
				%Plot new curve without erasing previous plots
hold on, plot(t2,y3,'g:'), hold off
title('Sinusoid y1(t) and y2(t), and Exponential y3(t)')
text(0.6,0.3,'y3(t)')
%______________________________________
				%To send active figure to printer, simply type
				%  print
print -deps plot1.ps		%Prints active figure to postscript file, can
				%then check it before printing on paper 8-)
%______________________________________
close(1)			%Close figure window #1
%______________________________________________________________________________
%  OTHER USEFUl FUNCTIONS: stem; semilogx; semilogy; loglog;
%______________________________________________________________________________