new_fod

NEW_FOD Creates a new FO transfer function approximation in ZPK

   NEW_FOD(r, N, wb, wh, b, d) creates a ZPK object with a refined
          Oustaloup filter approximation of a fractional-order operator
          s^r of order N and valid within frequency range (wb, wh).

          s^r = (d*wh/b)^r * (ds^2 + b*wh*s)/(d*(1-r)*s^2+b*wh*s+d*r)*Gp,
          where       
                      N
                    -----
               Gp =  | |  (s+w'k)/(s+wk),
                     | |
                    k= -N

               wk  = (b*wh/d)^((r+2k)/(2N+1)),
               w'k = (d*wb/b)^((r-2k)/(2N+1)).

          Should parameters b and d be omitted, the default values will be
          used: b=10, d=9.