中国激光, 2017, 44 (9): 0906006, 网络出版: 2017-09-07
基于改进相位生成载波解调的水表面声波激光相干探测 下载: 739次
Laser Interferometric Detection of Water Surface Acoustic Wave Based on Improved Phase-Generated Carrier Wave Demodulation
光通信 激光干涉 频率识别 相位载波 水表面波 水下声信号 communications laser interferometry frequency identification phase carrier water surface wave underwater acoustic signal
摘要
针对低频水表面声波(WSAW)的频率识别问题, 提出了一种基于改进相位生成载波(PGC)解调的激光相干探测方法。利用简单的激光干涉系统探测水下声源激发的低频WSAW, 再利用4路载波信号对其进行混频, 通过功率比较遴选出2路功率最大的正交干涉信号, 然后进行相位解调和频谱分析, 实现了WSAW的频率测定。仿真和实验研究表明, 改进的PGC解调法能够有效防止载波信号初始相位不可控条件下的正交信号消隐并准确实现低频WSAW的频率识别(频率探测下限可达30 Hz), 对变频WSAW及大尺度扰动波干扰条件下的低频WSAW也取得了很好的检测效果。该研究结果表明改进的PGC解调方法能够准确实现WSAW的频率识别, 并具有很强的抗干扰能力。
Abstract
In order to solve the problem of frequency identification of the low frequency water surface acoustic wave (WSAW), a laser interferometric detection method is proposed based on an improved phase-generated carrier wave (PGC) demodulation technique. A simple laser interferometer system is used to detect the low frequency WSAW caused by underwater acoustic sources. Frequency mixing of four carrier signals is conducted and two orthogonal interference signals are selected by power comparison. Further phase demodulation and spectrum analysis are carried out, and the frequency measurement for WSAW is achieved. Simulations and experiments for low frequency WSAW are conducted to confirm that the improved PGC demodulation method can effectively avoid orthogonal signal blanking when the initial phase of carrier signal is uncontrollable. The accurate frequency identification for WSAW can be achieved, and the frequency detection limit is as low as 30 Hz. Good detection effect for WSAM with low frequency can be achieved by the proposed method under conditions of frequency-varying WSAM and low-frequency WSAM with large-scale disturbance wave interference. The results show that the improved PGC demodulation method can accurately determine the frequency of WSAW and be able to resist disturbance.
张烈山, 张晓琳, 刘刚, 李开琴, 唐文彦. 基于改进相位生成载波解调的水表面声波激光相干探测[J]. 中国激光, 2017, 44(9): 0906006. Zhang Lieshan, Zhang Xiaolin, Liu Gang, Li Kaiqin, Tang Wenyan. Laser Interferometric Detection of Water Surface Acoustic Wave Based on Improved Phase-Generated Carrier Wave Demodulation[J]. Chinese Journal of Lasers, 2017, 44(9): 0906006.