Patent ID: 8314620

Claim:
A system for online relative phase calibration comprising: at least one excitation source configured to generate a plurality of excitation signals; at least two sensors coupled to respective ones of the at least one oscillator via a transmission line, the two sensors configured to receive respective ones of the excitation signals; at least two phase detectors configured to receive at least two incident and two reflected signals from the two sensors via the transmission line, each of the two phase detectors being configured to output a respective voltage representing a phase difference between respective ones of the reflected signals and respective ones of the excitation signals; a switch coupled to the sensors and the phase detectors, the switch configured to swap the phase detectors between the sensors at a pre-determined switching interval or in response to a calibration request signal; and a calibration module coupled to the phase detectors, the calibration module configured to receive and process the respective voltage from the at least two phase detectors to generate respective calibrated voltage signals, wherein the calibration module is further configured to and match the calibrated voltage signals of each of the phase detectors.