Which DFT formula is correct?

[powersys]

Some references give (1), while others give (2). Which DFT formula is correct? That is, should the right-hand side equation be divided by N?

Thanks.

 

[MHanif]

Hi
The formula given in reference (2) is mostly used.
Actually this depends how you define DFT and IDFT. Some people even define it by dividing formula given in Reference (2) by √N=sqrt(N).
It is only matter of choice. BUT if you use a DFT formula then see its Inverse DFT formula also. If two formula differ in scaling then their inverse will also differ by a scaling factor.
Hope this post clarifies you about DFT.

Waiting for your reply.
MHanif

 

[s_cihan_tek]

It doesn't matter as long as the product of the terms in front of the DFT and IDFT are equal to 1/N.

You can define the DFT using 1, 1/N or 1/sqrt(N). In these cases the term in front of the IDFT equation will be 1/N, 1 and 1/sqrt(N), respectively.