How do I find the separation between the harmonics for a graph of a function sinx/x against x?

I have used the following code to plot

x=linspace(-90,90,10000);

y=sin(x)./x;

plot(x,y);

axis([-90 90 -1.5 1.5])

xlabel('x')

ylabel('y')

title('A GRAPH OF A FUNCTION Y=(SINX)/X AGAINST X')

Answer 1

[Paul Hoffrichter]

Not sure if thisis what you are looking for.

x=linspace(-90,90,10000);
y=sin(x)./x;
figure(11)
plot(x,y);
axis([-90 90 -1.5 1.5])
xlabel('x')
ylabel('y')
title('A GRAPH OF A FUNCTION Y=(SINX)/X AGAINST X')

figure(12)
findpeaks(y,x);

[pks,locs] = findpeaks(y,x);
[pks' locs']

ans = 29×2

0.0112 -89.5320 0.0120 -83.2313 0.0130 -76.9487 0.0141 -70.6661 0.0155 -64.3834 0.0172 -58.1008 0.0193 -51.8182 0.0220 -45.5356 0.0255 -39.2529 0.0303 -32.9523

%     0.0375  -26.6697
%     0.0490  -20.3690
%     0.0709  -14.0684
%     0.1284   -7.7318
%     1.0000   -0.0090
%     0.1284    7.7318
%     0.0709   14.0684
%     0.0490   20.3690
%     0.0375   26.6697
%       . . .