Creating multiple polar plot graphs for different frequencies

Question

Cameron Latta 2019-10-19

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486278-creating-multiple-polar-plot-graphs-for-different-frequencies

回答： Daniel M 2019-10-19

采纳的回答： Daniel M

在 MATLAB Online 中打开

Essentially trying to use a loop to generate multiple plots for different values of f.

I get this error message:

Index exceeds the number of array elements (1).

Error in PistonDirectivity_2_11 (line 21)

f = f(n);

f = [125 250 500 1000 2000 4000 8000];
%f = 3.3820e+03;               %frequency
c = 340;             %speed of sound at 20 degrees
rho0 = 1.2;          %Acoustic impedance at 20 degrees
r = 100;                  %radius
a = 0.16;               %piston radius
u0 = 1;                 %particle velocity
theta = linspace(-pi/2+1.e-16,pi/2-1.e-16,181)'; %range of theta values from 90 to -90 degrees
%p = (1j*rho0*c*k*a^2*u0/(2*r) .* 2.* besselj(1,kasintheta)./kasintheta) * exp(-1j*k*r);
n = 1;
%% loop to make multiple plots
%while n < length(f)
for n = 1 : length(f)
    f = f(n);
    k = 2*pi*f./c;          %wavenumber
    p = besselj(1, k*a.*sin(theta))./(k*a.*sin(theta));
    db = 20*log10(abs(p));              %calculate dB and plot polar response
    mx = max(db);
    dynamic_range = 40;
    db = db + dynamic_range - mx;
    db = max(db,zeros(size(db)));
 
    polar(theta,db);   %plot polar response
    figure             %plot flat response
    plot(theta,db)
    xlabel('Theta (rads)')
    ylabel('Level (dB)')
    hold on
    
    n = n+1;
end