Fig. 7. Statistical diagram of effective information points of the original HHT spectrums and spectrums illustrated in Fig. 6. vannamei in the experiment can be described. When the signal frequency is limited to 0~24 kHz, the signal duration is about 5.5 ms, and the main frequency is within 12~18 kHz. The energy of the signal is strong within 0.6 ms at the beginning; during this time, the signal continuously outputs strong energy for about 0.06 ms, and the frequency is within about 14.9~15.3 kHz. The experimental results also show that the optimized HHT is effective in analyzing the timefrequency characteristics of the acoustic signals of Penaeus vannamei. Table 1 - Time and frequency span of optimized HHT spectrum after self-feedback Feedback (Relative intensity threshold) Primary feedback (0.3) Secondary feedback (0.5) Secondary feedback (0.9) April 2023 s1(t) 3.0~8.5 ms 11.5~17.1 kHz 3.0~8.5 ms 12.6~17.0 kHz 2.99~3.05 ms 14.9~15.3 kHz s2(t) 2.9~8.4 ms 11.7~17.8 kHz 2.9~6.3 ms 15.1~17.0 kHz - IEEE Instrumentation & Measurement Magazine s3(t) 2.6~7.8 ms 11.0~16.9 kHz 2.6~2.8 ms 13.5~17.3 kHz - 37