The Blackman function is an apodization function given by
 |
(1)
|
which has full width at half maximum of 
. This function is defined so
that the coefficients are approximations in the general
expansion
 |
(2)
|
to
 |  |  |
(3)
|
 |  |  |
(4)
|
 |  |  |
(5)
|
which produce zeros of 
at 
and 
.
The corresponding instrument function is
 |
(6)
|
where 
is the sinc function. It is full
width at half maximum is 
.
