Some use following expressions, which have the coefficient 
in the counter-part expression: (MATLAB uses this)
( n = 0, 1, 2, … N -1) (11.34)
and
( k = 0, 1, 2, … N -1) (11.35)
Of course, every definition has the same function as mapping. However, we must be careful when we interpret the physical meaning of the magnitude of the spectra. For example, for 
, it is equation (11.27) that gives a spectrum with magnitude 1.