The song is part of the definition of measurement, because the high-frequency active do better c taen, will be reduced as a result, the total between R 2 imphi dance with the lower c.
Song is at the limit of high frequency measurements because thicken the reactance of the c will be reduced, resulting impedance included between R2 and lower with c.
The song is the limit of measurement for high frequency can concentrate the reactance of the C are resulting in reduced impedance combined between R2 with C down low.