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Wigner Distribution in Optics   39


               u axis. The  -rotated smoothed interferogram P (x, u; w, z) for the
                                                         f
               optimal fractional angle   =−49 is presented in Fig. 1.6c for a rect-
                                           ◦
               angular window with T = 9 and in Fig. 1.6d for a Hann(ing) window
               with T = 15. We can see that as a consequence of the high concentra-
               tion of the components along the optimal fractional angle, we almost
               achieved the goal of getting the auto-terms of the Wigner distribution
               without any cross-terms.
                 Similar results are obtained for the signal


                                	 8
                              3x
                f (x) = exp −       (exp{i[	(x) + 50 x]}+ exp{i[	(x) − 50 x]})
                              x o
                                       x
                      with    	(x) =    15   arcsinh(100  ) d ,
                                     −∞
               where x o = X = 128 again and T = 21 see Fig. 1.7.




                          P f (x,u;w)                  P f (x,u;w,z)
                x                            x







                                          u                            u
                             (a)                          (b)
                                                        γ
                           γ
                          P f (x,u;w,z)                P f (x,u;w,z)
                x                            x






                                          u                            u
                             (c)                          (d)

               FIGURE 1.7 (a) Pseudo-Wigner distribution P f (x, u; w) of the signal f (x);
               (b) smoothed interferogram P f (x, u; w, z) calculated in the frequency
               domain, with a rectangular window z;(c) smoothed interferogram

                P (x, u; w, z) calculated in the optimal frequency domain, with a rectangular
                 f

               window z;(d) smoothed interferogram P (x, u; w, z) calculated in the
                                              f
               optimal frequency domain, with a Hann(ing) window z.
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