Measurement circuitry is disclosed that is configured to be coupled to a load through a transmission line. A first AC signal having a frequency ω1 is applied to the transmission line and a first input impedance of the transmission line is measured. A second AC signal having a frequency ω2 is applied to the transmission line and a second input impedance of the transmission line is measured, wherein the frequency ω2 is different than the frequency ω1. A third AC signal having a frequency ω is applied to the transmission line and a third input impedance of the transmission line is measured, wherein the frequency ω is different than the frequency ω1 and different than the frequency ω2. A resistance of the load is measured based on the measured first input impedance, the measured second input impedance, and the measured third input impedance.