残周期法在低频水听器灵敏度校准中的应用

Application of the Residual Period Method in Low-Frequency Hydrophone Sensitivity Calibration

为解决水听器灵敏度校准过程中由于水箱尺寸有限,水池中的反射无法避免,低频段存在反射叠加等导致低频段难以校准的问题,在自由场比较法的基础上通过对残周期信号的幅度、频率、相位三参数进行拟合,降低了灵敏度校准的频率下限。实验结果显示,该方法可实现2.5~20 kHz频段的灵敏度校准,误差在0.6dB之内,能够很好地消除由反射声场引起的校准误差,验证了该方法在低频校准中应用的有效性。然而残周期法在实际应用中也存在一些局限性,例如环境噪声、反射声场的衰减以及非线性等因素会对残周期法的准确性产生一定的影响。

This study addresses the challenges in calibrating hydrophone sensitivity at low frequencies,which arise from limitations in water tank dimensions,unavoidable reflections in water pools,and superposition of reflections in the low-frequency range.Building upon the free-field comparison method,we propose a technique that fits the amplitude,frequency,and phase of residual periodic signals to lower the frequency limit for sensitivity calibration.Experimental results demonstrate that this method enables sensitivity calibration in the 2.5-20 kHz frequency range,with errors within 0.6 dB.It effectively eliminates calibration errors caused by reflected sound fields,validating its efficacy in low-frequency calibration.However,the residual period method has some practical limitations.Factors such as environmental noise,attenuation of reflected sound fields,and nonlinear effects can impact the method's accuracy.Despite these challenges,the proposed approach shows promise in expanding the frequency domain for hydrophone calibration,particularly in low-frequency ranges where traditional methods face significant obstacles.