discrete fourier transform

[KhaledOsmani]

How to make a circular convolution, for two signals x1 and x2 of the same size , of 4.

i.e x1 = {2,1,2,1} and x2 = {1,2,3,4}

y = x1 circonv x2 = ??

 

[ads-ee]

Obviously you didn't perform even a rudimentary search....

Google produces the following result, which is on this board.
https://www.edaboard.com/threads/180754/

 

[KhaledOsmani]

How to calculate Mod using fx-570ES PLUS calculator?

- - - Updated - - -

X1(k) = {7,−2 − j, 1,−2 + j}
X2(k) = {11, 2 − j, 1, 2 + j}
⇒ X3(k) = X1(k)X2(k)
= {17, 19, 22, 19}

Justification please