Fig. 1. Relationship curve of characteristic ratio to amplitude of WSAW (As is in the interval of 0.5—25 nm).

Fig. 2. Fourier spectrum of the simulated interference signal.

Fig. 3. Laboratory setup for amplitude measurement of WSAW.

Fig. 4. Schematic of (a) time-domain waveform (the DC component was filtered) and (b) Fourier spectrum of experimental detection signal for 4 kHz WSAW.

Fig. 5. Experimental results of amplitude measurements for WSAWs with different frequencies. SPL of underwater sound was kept at 80, 85, 90 and 95 dB.

Fig. 6. Experimental results of amplitude measurements for WSAWs caused by different incident sound pressures. Frequencies of WSAWs were kept at 1, 2, 3 and 4 kHz.