Module 9 :
Numerical Relaying II : DSP Perspective
Lecture 33 :
Discrete Fourier Transform
33.1
Motivation (contd..)
Note that in general DFT and inverse DFT can be defined in many ways, each only differing in choice of constant and . Thus, the generic form of DFT and IDFT is as follows:
DFT
i.e.
IDFT
The constraint in choosing the constraints is that product
For example, when
Choice of is commonly used in relaying because it simplifies phasor estimation.
and 
. Thus, the generic form of DFT and IDFT is as follows:
is commonly used in relaying because it simplifies phasor estimation. 
