ILD10000 = [
    18 90;
    16 60;
    10 30;
    0 0;
     -10 -30;
     -16 -60;
    -18 -90;  
    ];
    ILD5000 = [
      12 90;
      10.5 60;
       7 30;
       0 0;
       -7 -30;
        -10.5 -60;
        -12 -90;
       ];
    ILD1000 = [
        6 90;
         5.5 60;
         3.5 30;
         0 0;
          -3.5 -30;
         -5.5 -60;
          -6 -90;
         ];
     ILD250 = [
        2.5 90;
         2.2 60;
         1 30;
         0 0;
          -1 -30;
         -2.2 -60;
          -2.5 -90;
         ];

figure(1); clf;
plot(ILD10000(:,2), ILD10000(:,1), 'ks-','linewidth',2);
hold on
text(-90, -0.9, '250 Hz', 'fontsize',11,'fontweight','bold');

plot(ILD5000(:,2), ILD5000(:,1), 'ks-.','linewidth',1.5);
text(-90, -5, '1 kHz', 'fontsize',11,'fontweight','bold');

plot(ILD1000(:,2), ILD1000(:,1), 'ks--','linewidth',1.5);
text(-90, -11, '5 kHz', 'fontsize',11,'fontweight','bold');

plot(ILD250(:,2), ILD250(:,1), 'ks:','linewidth',1.5);
text(-90, -16, '10 kHz', 'fontsize',11,'fontweight','bold');

str = '$$ILD(\alpha, f) = 0.18 \cdot \sqrt{f} \cdot \sin (\alpha)$$';
text(-90, 5, str, 'Interpreter','latex','fontsize',12, 'color','r' );

x=[-90:10:90];
f = 10000;
y = 18/100*sqrt(f)*sin(x*pi/180);
%y = 18*(1-exp(-f/4000))*atan(x*pi/180);
plot(x,y,'r-');
f = 5000;
y = 18/100*sqrt(f)*sin(x*pi/180);
%y = 18*(1-exp(-f/4000))*atan(x*pi/180);
plot(x,y,'r-');
f = 1000;
y = 18/100*sqrt(f)*sin(x*pi/180);
%y = 18*(1-exp(-f/4000))*atan(x*pi/180);
plot(x,y,'r-');
f = 250;
y = 18/100*sqrt(f)*sin(x*pi/180);
%y = 18*(1-exp(-f/4000))*atan(x*pi/180);
plot(x,y,'r-');
set(gca, 'fontsize',12,'fontweight','bold');
xlabel('Azimuth (deg)', 'fontsize',13,'fontweight','bold');
ylabel('ILD (dB)', 'fontsize',13,'fontweight','bold');

print -djpeg Fig7-10
figure(2); clf
ILDb = [
    10000 18;
    5000 12;
    1000 6;
    250 2.5;
    ];
plot(sqrt(ILDb(:,1)), ILDb(:,2), 'ks-','linewidth',2);
    