In fitteia consider the following definitions in the appropriate fields in the fitter module:

1. Independent variable: f

2. Dependent variable: R1

3. Expression: R1=A*pow(2*pi*f,1-alpha)*(
   lor(pow(tau,alpha),pow(2*pi*f,alpha))
   +
   pow(2.0,1+alpha)*lor(pow(tau,alpha),pow(4*pi*f,alpha))
   )

4. Fitting parameters: A, tau, alpha

5. Typical values: A=3.4×10⁹ s^-2, tau=10^-9s, alpha=free

Function pow(x) is part of the C mathematical functions' library.