Ameliorted algorithm for PGC to eliminate the influence of carrier phase delay with FFT

In the real environment, the carrier phase delay (0) is difficult to accurately maintain at n pi (n is an integer), which results in the demodulation error of the phase generation carrier (PGC) demodulation algorithm. In this paper, the fast Fourier transform (FFT) technique is used to extract 100, 200, 300, 400 from the first to fourth harmonic signals of the interference signal, then introduce 100, 200, 300, 400 into the mixed signal as the initial phase, and finally perform a mixing operation to real time eliminate the carrier phase delay. The experiments show that when the carrier delay is in the range of 0 to pi, the SINAD of the ameliorated algorithm reaches 43.66 dB, which is 19.31 dB higher than the PGC-Arctan algorithm on average. The THD of the ameliorated algorithm can be stabilized at 0.183 %, which always maintains the best level of the PGC-Arctan algorithm. The ameliorated algorithm eliminates the carrier phase delay and does not have the phase singularity, thus expanding the application range of the fiber optic interferometer sensor.