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 signalprocessing system, wherein an optimal value of a phase modulation coefficientis calculated for each laser and used as the amplitude of a cosine wave signalfor the laser module carrier frequency for phase modulation of the laseroutputsignal. The phase modulation coefficient is determined from a global averageI/Q ratio, calculated for all channels of the selected laser module, as anaverage of all I/Q ratios of in-phase and quadrature phase angle components ofthe signals returned from the sensors. The phase modulation coefficient fortheselected laser module is determined empirically or by dividing the previouslydetermined phase modulation coefficient by the previously determined globalaverage I/Q ratio.