Comparative study of phase demodulation approaches based on PGC and Heterodyne

To meet the sensibility and frequency band need of an fiber-optic Hydrophone system, phase demodulation approaches are proposed to research, which are a PGC-DCM (phase generated carrier-Differentiate Cross Multiply), a PGC-Arctangent, a Heterodyne-DCM and a Heterodyne-Arctangent. The paper demonstrates Heterodyne and PGC schemes in detail, and compares their properties. By Matlab numerical modeling and Simulink simulating, the undistorted demodulation can be achieved with Heterodyne or PGC approach, and four algorithms are compared in demodulation frequency and demodulation amplitude. With comparing and analyzing signal frequency band and amplitude band, it shows that Heterodyne-Arctangent is the best algorithm about demodulation frequency and demodulation amplitude in all of the four demodulation approaches. Meanwhile the demodulation performance of Heterodyne-Arctangent is that the frequency is up to 7000 Hz and the amplitude is up to 40 rad. It is important for the studying and applying about demodulation technology of a Michelson fiber-optic hydrophone system.