光纤水听器相位生成载波解调非线性因素的抑制方法

Nonlinear factors suppression method of phase generated carrier demodulation of optical fiber hydrophone

为了消除非线性因素对相位生成载波解调结果的干扰,降低相位生成载波解调过程中低通滤波器的频响特性对相位生成载波解调结果的影响,该文提出了一种基于扩展卡尔曼滤波椭圆参数估计的相位生成载波微分交叉相乘解调方法。该方法在综合考虑各种非线性因素对相位生成载波微分交叉相乘解调结果的影响的基础上,对传统的相位生成载波微分交叉相乘解调过程进行了改进。经过计算机仿真和实验验证,该文所提出的扩展卡尔曼滤波微分交叉相乘方法能够有效地抑制非线性因素对相位生成载波解调结果的干扰,相比传统的相位生成载波微分交叉相乘方法,其信噪比提高了35.0 dB,总谐波失真降低了30.7 dB,信噪谐波比提高了31.0 dB,且扩展卡尔曼滤波微分交叉相乘方法受解调过程中低通滤波器频响特性的影响较小。

In order to eliminate the interference of nonlinear factors on phase generated carrier(PGC)demodulation results and reduce the influence of the frequency response characteristics of low-pass filter on PGC demodulation results in the process of PGC demodulation,this paper proposes a PGC differential and cross multiplying(DCM)demodulation method based on extended Kalman filter(EKF)elliptic parameter estimation(EKF-DCM).This method modifies the traditional PGC-DCM demodulation process,and uses the EKF based elliptic parameter estimation method to estimate the model parameters in the improved PGC-DCM demodulation process.Through computer simulation and experimental verification,the EKF-DCM method proposed in this paper can effectively suppress the interference of nonlinear factors on PGC demodulation results.Compared with the traditional PGC-DCM method,its signal-to-noise ratio is increased by 35.0 dB,its total harmonic distortion is reduced by 30.7 dB,and its signal-to-noise harmonic ratio is increased by 31.0 dB.And the EKF-DCM method is less affected by the frequency response characteristics of low-pass filter in the demodulation process.