The jinc function is defined as

where is a Bessel Function of the First Kind, and satisfies . The Derivative of the jinc function is given by

The function is sometimes normalized by multiplying by a factor of 2 so that (Siegman 1986, p. 729).

**References**

Siegman, A. E. *Lasers.* Sausalito, CA: University Science Books, 1986.

© 1996-9

1999-05-25