How can I get a sinc function like this?
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payman khayree
on 7 Sep 2014
Commented: Image Analyst
on 8 Sep 2014
As we know there is a sinc function in matlab which calculates the sinc of the data. But I need to
get a sinc function that look like the image.
what mathematical properties should I change to turn the standard sinc function into one like this?
6 Comments
Image Analyst
on 8 Sep 2014
Perhaps, but not that I know of. Where did you see it? Did that place give a name for it? (I guess not otherwise you wouldn't be asking us.) It sort of looks like a sinc squared (the diffraction pattern of a thin slit, or a sombrero function (the optical diffraction pattern of a small circular aperture). Search sombrero or the cross section of a see this Wikipedia article
Accepted Answer
Image Analyst
on 8 Sep 2014
This is about the closest I could get after playing around with it for a few minutes:
x = 1:400;
y = abs(0.055 * sinc((x - 195) / 12)) - 0.001;
% Smooth out a bit
y = conv(y, [1,1,1]/3, 'same');
plot(x, y, 'b-', 'LineWidth', 3);
grid on;
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off')
Why do you need this, and if you need it, why don't you have the formula for it? Where did you hear of it? Didn't they give you the formula?????
5 Comments
Image Analyst
on 8 Sep 2014
No, not easy if you have to just do trial and error. But if you don't have something known, then how do you know if your formula has gotten it right? And if you do have something knonwn, whether numerical data or a formula, then just use it.
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