 |
(1)
|
Its full width at half maximum is 
.
Its instrument function is
 |  |  |
(2)
|
 |  |  |
(3)
|
where 
is a Bessel function of the first kind.
This function has a maximum of 
. To investigate the instrument function, define the dimensionless
parameter 
and rewrite the instrument function as
 |
(4)
|
Finding the full width at half maximum then amounts to solving
 |
(5)
|
which gives 
,
so for 
,
the full width at half maximum is
 |
(6)
|
The maximum negative sidelobe of 
times the peak, and maximum positive
sidelobe of 0.356044 times the peak.
