Improved Algorithm for Phase Generation Carrier to Eliminate the Influence of Modulation Depth With Multi-Harmonics Frequency Mixing

Traditional phase generation carrier technology requires to control the modulation depth at an optimal value for accurate demodulation. In this paper, we proposed an algorithm to directly eliminate the real-time phase modulation depth based on multi-harmonics frequency mixing technology for avoiding the influence of phase modulation depth on the demodulation result. Experiments show that when the modulation depth is in the range of 1.5 to 3.5 rad, the SINAD of the improved algorithm can reach 37.1 dB, which is 13.2 dB higher than that of the traditional PGC-Arctan algorithm on average. The THD of the improved algorithm can reach 0.322%, which always maintains the best level of the traditional PGC-Arctan algorithm. The algorithm provides an effective reference for the signal processing of the fiber-optic interferometric sensors in practical applications.