Methods (200, 300) for determining a reference signal (Vref). The methods involve (202, 204, 302, 304) sensing at a first location along the transmission media (108, 502) a first signal (Vf) propagated thereover in a forward direction and a second signal (Vr) propagated thereover in a reverse direction opposed from the forward direction. The second signal being a reflected version of the first signal. A sum signal (S) is determined (206, 306) by adding the first and second signals together. A difference signal (D) is determined (208, 308) by subtracting the second signal from the first signal. Thereafter, a first exponentiation signal (ES) is determined (210, 310) using S. A second exponentiation signal (ED) is determined (212, 312) using D. The first exponentiation signal is subtracted (214, 314) from the second exponentiation signal to obtain a reference signal (Vref). Vref can be determined at any location along the transmission media. Vref can be used to control the phases and/or amplitudes of communication signals.