Method and apparatus for calibration of a multi-channel fiber optic interferometric sensor system in a signal processing system

摘要

A calibration technique for lasers of a data acquisition module in a signal processing system, wherein an optimal value of a phase modulation coefficient is calculated for each laser and used as the amplitude of a cosine wave signal for the laser module carrier frequency for phase modulation of the laser output signal. The phase modulation coefficient is determined from a global average I/Q ratio, calculated for all channels of the selected laser module, as an average of all I/Q ratios of in-phase and quadrature phase angle components of the signals returned from the sensors. The phase modulation coefficient for the selected laser module is determined empirically or by dividing the previously determined phase modulation coefficient by the previously determined global average I/Q ratio.