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Uniform Apodization Function


UniformApodization

An apodization function

 A(x)=1,
(1)

having instrument function

 I(k)=2asinc(2pika).
(2)

The peak of I(k) is 2a. The full width at half maximum of I(k) can found by setting r=2pika to obtain

 sinc(r)=1/2,
(3)

and solving for r_(1/2), yielding

 r_(1/2)=2pik_(1/2)a=1.89549.
(4)

Therefore, with L=2a,

 FWHM=(1.20671)/L.
(5)

The extrema are given by taking the derivative of I(k), substituting r=ka, and setting equal to 0

 2pixcos(2pix)-sin(2pix)=0.
(6)

Solving this numerically gives sidelobes at 0.715148 (-0.434467), 1.22951 (0.256749), 1.73544 (-0.18265), ....


See also

Apodization Function, Instrument Function

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References

Press, W. H.; Flannery, B. P.; Teukolsky, S. A.; and Vetterling, W. T. Numerical Recipes in FORTRAN: The Art of Scientific Computing, 2nd ed. Cambridge, England: Cambridge University Press, pp. 554-556, 1992.

Referenced on Wolfram|Alpha

Uniform Apodization Function

Cite this as:

Weisstein, Eric W. "Uniform Apodization Function." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/UniformApodizationFunction.html

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