Contents

% /home/dimarzio/Documents/working/12303/matlab/sq_wave_demo.m
% Sun Nov 18 18:35:50 2018
%
% Square Wave Demo

npts=2^16;timespan=1e-2;
t=[0:npts-1]*timespan/npts;  % Time axis
% Sampling Frequency
dt=t(2)-t(1)
fsample=1/dt
f=2^3/timespan;
omega=2*pi*f;

dt =
   1.5259e-07
fsample =
     6553600

Square Wave

square=10*double(sin(omega*t)>0);
fdisplay=12*f; % Max frequency to display
[pt,pf,fax,SQUARE]=plotpair(t,square,fdisplay);
figure(pt);xlabel('t, Time, Sec');title('Square Wave');
figure(pf);xlabel('f, Frequency, Hz');title('Square Wave');

How much does it look like DC?

term0=5*ones(size(square));
s0=square-term0;
[pt,pf,fax,TERM0]=plotpair(t,term0,fdisplay);
figure(pt);xlabel('t, Time, Sec');title('DC');
figure(pf);xlabel('f, Frequency, Hz');title('DC');
[pt,pf,fax,S0]=plotpair(t,s0,fdisplay);
figure(pt);xlabel('t, Time, Sec');title('What''s Left After DC');
figure(pf);xlabel('f, Frequency, Hz');title('What''s Left After DC');

How much does it look like sin(omega*t)?

term1=5*sin(omega*t)*4/pi;
s1=s0-term1;
[pt,pf,fax,TERM1]=plotpair(t,term1,fdisplay);
figure(pt);xlabel('t, Time, Sec');title('Fundamental');
figure(pf);xlabel('f, Frequency, Hz');title('Fundamental');
[pt,pf,fax,S1]=plotpair(t,s1,fdisplay);
figure(pt);xlabel('t, Time, Sec');title('What''s Left After Fundamental');
figure(pf);xlabel('f, Frequency, Hz');title('What''s Left After Fundamental');
square1=term0+term1;
[pt,pf,fax,SQUARE1]=plotpair(t,square1,fdisplay);
figure(pt);xlabel('t, Time, Sec');title('Sum Through Fundamental');
figure(pf);xlabel('f, Frequency, Hz');title('Sum Through Fundamental');

How much does it look like sin(3*omega*t)?

term3=5/3*sin(3*omega*t)*4/pi;
s3=s1-term3;
[pt,pf,fax,TERM3]=plotpair(t,term3,fdisplay);
figure(pt);xlabel('t, Time, Sec');title('Third Harmonic');
figure(pf);xlabel('f, Frequency, Hz');title('Third Harmonic');
[pt,pf,fax,S3]=plotpair(t,s3,fdisplay);
figure(pt);xlabel('t, Time, Sec');title('What''s Left After Third Harmonic');
figure(pf);xlabel('f, Frequency, Hz');title('What''s Left After Third Harmonic');
square3=term0+term1+term3;
[pt,pf,fax,SQUARE3]=plotpair(t,square3,fdisplay);
figure(pt);xlabel('t, Time, Sec');title('Sum Through Third Harmonic');
figure(pf);xlabel('f, Frequency, Hz');title('Sum Through Third Harmonic');

How much does it look like sin(5*omega*t)?

term5=5/5*sin(5*omega*t)*4/pi;
s5=s3-term5;
[pt,pf,fax,TERM5]=plotpair(t,term5,fdisplay);
figure(pt);xlabel('t, Time, Sec');title('Fifth Harmonic');
figure(pf);xlabel('f, Frequency, Hz');title('Fifth Harmonic');
[pt,pf,fax,S5]=plotpair(t,s5,fdisplay);
figure(pt);xlabel('t, Time, Sec');title('What''s Left After Fifth Harmonic');
figure(pf);xlabel('f, Frequency, Hz');title('What''s Left After Fifth Harmonic');
square5=term0+term1+term3+term5;
[pt,pf,fax,SQUARE5]=plotpair(t,square5,fdisplay);
figure(pt);xlabel('t, Time, Sec');title('Sum Through Fifth Harmonic');
figure(pf);xlabel('f, Frequency, Hz');title('Sum Through Fifth Harmonic');

Published with MATLAB® R2017a