Approximating TDEV at the model output

In this section, the limiting expressions obtained in sections 6.2.1 and 6.2.2 will be used to obtain values for K_f and K_w compliant with the TDEV masks specified in the ETSI standards.

Considering the results of sections 6.2.1 and 6.2.2, it is evident that the bottom branch is dominant at small $\tau$ and the top branch is dominant at large $\tau$. Approximate values for the order of K_f and K_w may be obtained by taking the approximations

and hence