Fig. 1. Flowchart of DCM demodulation algorithm

Fig. 2. Simulation of orthogonal interference signals. (a) UI(t); (b) UQ(t)

Fig. 3. Simulation of phase demodulation signal. (a) Time domain; (b) frequency domain

Fig. 4. Flowchart of improved PGC demodulation method

Fig. 5. Simulated orthogonal interference signals based on improved PGC demodulation method. (a) UI(t); (b) UQ(t)

Fig. 6. Demodulation results of simulated signal based on improved PGC demodulation method. (a) Time domain; (b) frequency domain

Fig. 7. Schematic of experimental system

Fig. 8. Demodulation results of 200 Hz WSAW interference signal. (a) Traditional PGC demodulation method; (b) improved PGC demodulation method

Fig. 9. (a) Orthogonal signals obtained by traditional PGC demodulation method; (b) orthogonal signals obtained by improved PGC demodulation method

Fig. 10. Demodulation results of low frequency WSAW detection signals with different frequencies. (a) 30 Hz; (b) 50 Hz; (c) 100 Hz; (d) 500 Hz

Fig. 11. (a) Laser interference detection signal of sweep frequency WSAW; (b) result obtained by improved PGC demodulation method; (c) time-frequency distribution of demodulation signal

Fig. 12. (a) Time domain distribution and (b) frequency domain distribution of measured 200 Hz WSAW interference signal

Fig. 13. (a) Demodulation result of traditional PGC demodulation method; (b) demodulation result of improved PGC demodulation method