Cho X ( e j w ) = e j 4 w + 2 + e − j w 4 . I F T [ X 3 ( e j w ) ] được xác định bằng:

$x\left(n\right)=\delta \left(n+4\right)+2+\delta \left(n-4\right)$

$x\left(n\right)=\delta \left(n+4\right)+2\delta \left(n\right)-\delta \left(n-4\right)$

$x\left(n\right)=\delta \left(n+4\right)-2\delta \left(n\right)+\delta \left(n-4\right)$

$\text{x}\left(\text{n}\right)=\delta \left(\text{n}+4\right)+2\delta \left(\text{n}\right)+\delta \left(\text{n}-4\right)$