Dave wrote:
if the frequency is fixed, is sinusoidal, and steady state,
then every box that measures -j567 ohms is perfectly equal.

If the goal is to measure the phase shift at an
impedance discontinuity in a transmission line, why
would someone deliberately put the impedance discontinuity
inside a black box? That defeats the goal of measuring
the phase shift.
--
73, Cecil http://www.w5dxp.com