y\2 
4n 
N 
Fig. 2.9. Fejer Kernel Function Fepy(®) 
Therefore, 
N 
lim F =— lim 
¢—0 en) 27 6-0 
Putting this function F,,(@) into Eq. 2.71 gives 
| 
sin 0 
6 
ce 
ia 
1 
E [Py(w)] = | s)5 [Feld +w)+Fe(p—w)} dp. 
Taking into account the form of the Fejer kernel Fy gives 
= | s@F.6-w) do . 
When N—> ~, 
Fp) > 0), 
F,,, tends to Dirac’s delta function, and 
26 
(2.76) 
(2.77) 
(2.78) 
(2.79) 
