An energy delivery system for use in performing a medical procedure is provided. The medical procedure can employ an energy source, the energy source can be connected to an energy delivering device via a transmission line. The energy delivery system can include a measurement system, the measurement system can be configured to sample an output signal generated by the energy source. The energy delivery system includes a control system, which includes a calibration unit. The calibration unit can be configured to generate a calibration signal. The calibration signal can have a magnitude and phase, wherein the magnitude and phase is representative of the output signal and the transmission line loss information. The energy delivery system can also include a control unit, the control unit being configured to receive the calibration signal and adjust the energy source as needed.