% Project 2 # 4: electronically-steered one-dimentional loudspeaker array
L=4.2;
theta=-pi/2:pi/360:pi/2;        
c=345;
cs=489; %this is the speed of the wavelength for the theta=45 degrees
                       %theta=asin(c/cs)
                       %pi/4=asin(345/cs)
for f=300
    k=2*pi*f/c;
    lambda=c/f;
    lambda_s=cs/f;
    u=(L/lambda).*sin(theta);   
    G=sin(pi*(u-L/lambda_s))./(pi*(u-L/lambda_s));          %sinc function  
    G=abs(G); 
    subplot(2,2,1)
    polar(theta,G,'m-')       %Plot
    title(['Beam Pattern, L = ',num2str(L),'m',', cs = ',num2str(cs),'m/s, f = ',num2str(f),'Hz'])
    pause(.6)
end
for f=3000
    k=2*pi*f/c;
    lambda=c/f;
    lambda_s=cs/f;
    u=(L/lambda).*sin(theta);   
    G=sin(pi*(u-L/lambda_s))./(pi*(u-L/lambda_s));          %sinc function  
    G=abs(G); 
    subplot(2,2,2)
    polar(theta,G,'m-')       %Plot
    title(['f = ',num2str(f),'Hz'])
    pause(.6)
end
for f=5000
    k=2*pi*f/c;
    lambda=c/f;
    lambda_s=cs/f;
    u=(L/lambda).*sin(theta);   
    G=sin(pi*(u-L/lambda_s))./(pi*(u-L/lambda_s));          %sinc function  
    G=abs(G); 
    subplot(2,2,3)
    polar(theta,G,'m-')       %Plot
    title(['f = ',num2str(f),'Hz'])
    pause(.6)
end
for f=10000
    k=2*pi*f/c;
    lambda=c/f;
    lambda_s=cs/f;
    u=(L/lambda).*sin(theta);   
    G=sin(pi*(u-L/lambda_s))./(pi*(u-L/lambda_s));          %sinc function  
    G=abs(G); 
    subplot(2,2,4)
    polar(theta,G,'m-')       %Plot
    title(['f = ',num2str(f),'Hz'])
    pause(.6)
end
%Particle Displacement:

f=2000;
c=345;
k=2*pi*f/c;
L=4.2;
lambda=c/f;
[X,Y] = meshgrid(0:.01:2,-3:.1:3);
R=sqrt((X.^2)+(Y.^2));
sin_thetaN=abs(X)./R;
u=(L*sin_thetaN)./lambda;
m=pi*(u-L/lambda_s);
p=(cos(k*R)./R).*(sin(m)./m);
figure(2);
meshc(X,Y,p);
shading interp;
%colormap(pink);
COLORMAP('default')
title(['Particle Displacement at Frequency = ',num2str(f),', Angled View with a countour curtain using meshc'])
figure(3);
surfl(X,Y,p)
title(['Particle Displacement at Frequency = ',num2str(f),', Angled View using surf1'])
figure(4);
surfl(X,Y,p); 
shading interp;
colormap(pink);
title(['Particle Displacement at Frequency = ',num2str(f),', Side View using surf1'])