 | (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.
