The micro-vibration amplitude measuring method with suppressing peak-to-peak drift in PGC demodulation algorithm

In order to suppress peak-to-peak drift in traditional phase generated carrier (PGC) demodulation, a novel ameliorated PGC demodulation algorithm based on differentiate and cross multiply demodulation (DCM) and sum of squares of orthogonal signals is proposed in this paper. This improvement has several advantages compared with the traditional PGC algorithm. The drift of the light power is eliminated and will not be transferred to the output. The noise from the light power is reduced much at the same time. Experimental results established by using dual-channel balancing detection technology and digital demodulation have confirmed the low intensity noise of the ameliorated PGC algorithm as expected as the theoretical analysis. The peak-to-peak value drift in the ameliorated PGC demodulation has been suppressed effectively. According to the experimental results, the demodulated amplitude and the test signal amplitude assumes certain linear relationship. The conclusion has the important reference significance to improve the performance of the system.