Biến đổi Fourier của dãy nào sau đây tồn tại A. X ( e j ϖ ) = u ( n ) − u ( n − 3 ) − u ( n − 5 )

$X\left(e{}^{j\varpi }\right)=\text{u}\left(\text{n}\right)-\text{u}\left(\text{n}-3\right)-\text{u}\left(\text{n}-5\right)$

$X\left(e{}^{j\varpi }\right)=\text{r}\left(\text{n}\right)-\text{r}\text{e}\text{c}\text{t}{}_4\left(\text{n}-3\right)$

$X\left(e{}^{j\varpi }\right)=\text{u}\left(\text{n}-3\right)$

$X\left(e{}^{j\varpi }\right)=\text{u}\left(\text{n}\right)-\text{u}\left(\text{n}-5\right)+\text{r}\text{e}\text{c}\text{t}{}_4\left(\text{n}-3\right)$