干涉型光纤水听器PGC解调的参数估计方法

对于干涉型光纤水听器外调制式相位生成载波(PGC)解调方案,光干涉强度和调制深度两个参数的波动会影响解调结果。为了消除影响,本文提出利用椭圆曲线拟合以及频域搜索的参数估计方法。根据理论分析,当调制深度在0,3.83]区间内两种方法有效,可以适应实际情况中调制深度缓慢且小范围波动的情况。为了分析验证两种方法,本文利用不同类型的待测信号进行了数值仿真,根据仿真结果,在声信号引起的相位较大的情况下,两种方法都能对参数进行正确估计;利用频域搜索的方法适用的动态范围更大;当相关参数缓慢波动时,频域搜索法能正确跟踪估计相关参数。

Estimation of parameters for PGC demodulation in interferometric fiber hydrophone

In PGC demodulation scheme for outer modulation of interferometric fiber hydrophone, demodlation results will be affected by interference intensity and modulation depth. In order to cancel the effect, parameters estimation methods base on elippse curve fitting and frequency energy seeking are proposed. According to thesis analysis, the two methods will be valid when modulation depth fluctuates between 0 and 3.83, that meet the actual situation. Simulations are carried out based on different type of signal to be detected. According to simulation results, the two methods can estimate the parameters correctly under larger phase, the dynamic range of frequncy seeking method is more larger than that of ellipse fitting, and frequency seeking method can track the two parameters when the paremeters fluctuate slowly.