基于高稳定性的PGC解调算法研究

Research on PGC demodulation algorithm based on high stability

为了解决传统相位生成载波(PGC)解调算法在光强扰动和调制深度漂移引起的解调失真现象,采用基波混频和差分自乘的改进PGC解调算法,进行了相关的理论分析和仿真验证。结果表明,该算法能很好地抑制光强扰动引起的失真,在引入1.5rad~3.5rad的光强扰动时可以达到近30dB的信纳比,比传统的离散余弦变换算法高出近15dB;同时能消除对调制深度C的依赖性,可以实现低于0.1%的总谐波失真和30dB的信纳比,比传统算法高出近10dB,线性度高达99.99%。该研究为光纤干涉型传感的解调提供了一种新的方案。

In order to solve the demodulation distortion caused by light intensity disturbance and modulation depth drift in traditional phase generated carrier(PGC)demodulation algorithm,an improved PGC demodulation algorithm based on fundamental wave mixing and differential self multiplication was adopted.And relevant theoretical analysis and simulation verification were carried out.The results show that the distortion caused by light intensity disturbance can be suppressed,and the demodulation efficiency can be improved at the same timeby using this algorithm.When the light intensity disturbance of 1.5rad~3.5rad was introduced,the signal-to-noise and distortion ratio of nearly 30dB was obtained,which was 15dB higher than the traditional discrete cosine transform(PGC-DCM)algorithm.In addition,the dependence on modulation depth C can be eliminated,and the total harmonic distortion of less than 0.1%and the signal-to-noise ratio of 30dB can be achieved,which was nearly 10dB higher than the traditional algorithm,and the corresponding linearity was up to 99.99%.It provides a new scheme for the demodulation of optical fiber interferometric sensor.