海洋电场变频调谐窄带抑制噪声的测量方法  

Measurement of narrowband noise suppression by frequency tuning of marine electric field

作　　者：刘子逸 李平[1] 文玉梅[1] 叶敬昌 Liu Ziyi;Li Ping;Wen Yumei;Ye Jingchang(School of Electronic Information and Electrical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学电子信息与电气工程学院,上海200240

出　　处：《仪器仪表学报》2025年第2期305-313,共9页Chinese Journal of Scientific Instrument

基　　金：国家重点研发计划(2022YFB3205703)项目资助。

摘　　要：海洋电场测量对于监测海洋活动、探测海底资源具有重要意义。由于海洋电场信号频率低,对于微弱的信号,电场测量不可避免受到器件的1/f噪声和环境变频谐波噪声的影响,其中环境变频谐波噪声的频率可能非常接近待测电场信号,难以通过现有的斩波放大技术抑制。针对现有测量电路难以抑制环境变频谐波噪声的问题,提出了一种开关变频石英晶体谐振窄带抑制噪声的海洋电场测量方法,将海洋电场变频到32.768 kHz,上变频信号经过高Q值石英晶振实现超窄带滤波的海洋电场测量。通过对开关变频海洋电场的过程以及变频调谐窄带测量电路的选频特性进行理论分析,推导出变频调谐窄带测量输出信号的表达式。搭建了电场测量实验平台,对设计的变频调谐窄带测量电路进行了实验测试。实验结果表明,当海洋电场信号频率为0.01~0.2 Hz时,变频调谐窄带测量的灵敏度是直接测量的2.78倍,测量电路的带宽<0.4 Hz。对于频率为0.1 Hz的海洋电场信号,变频调谐窄带测量的信噪比相比于直接测量提高了19.82 dB。这种方法不仅可以用于强噪声下微弱海洋电场信号的识别和测量,还可以用于未来海洋电场测量阵列的构建。Marine electric field measurement is of significant importance for monitoring marine activities and exploring seabed resources.Due to the low-frequency characteristics of marine electric field signals,weak signal measurement is inevitably affected by device 1/f noise and environmental frequency-conversion harmonic noise.Notably,the frequency of environmental frequency-conversion harmonic noise may closely approach that of the target electric field signals,making it difficult to suppress using existing chopper amplification techniques.To address the challenge of existing measurement circuits in suppressing environmental frequency-conversion harmonic noise in conventional measurement circuits,this article proposes a marine electric field measurement method incorporating switched-frequency conversion quartz crystal resonance narrowband noise suppression.The approach converts marine electric field to 32.768 kHz,and the up-converted signal undergoes ultra-narrowband filtering via a high-Q quartz crystal resonator.Theoretical analysis is conducted on the frequency-conversion tuning process of the marine electric field and the frequency-selective characteristics of the proposed measurement circuit,leading to the derivation of the expression for the output signal after frequency-conversion tuning narrowband processing.An experimental platform for electric field measurement is established,and the designed frequency-conversion tuning narrowband measurement circuit is tested.Experimental results show that when the marine electric field signal frequency ranges from 0.01 to 0.2 Hz,the sensitivity of the frequency-conversion tuning narrowband measurement reaches 2.78 times that of direct measurement,with a circuit bandwidth of less than 0.4 Hz.For a marine electric field signal at 0.1 Hz,the signal-to-noise ratio of the frequency-conversion tuning narrowband measurement shows a 19.82 dB improvement compared to direct measurement.This method not only enables the detection and measurement of weak marine electric field signals in

关 键 词：海洋电场测量 窄带滤波 石英晶振 

分 类 号：TH89[机械工程—仪器科学与技术] TM93[机械工程—精密仪器及机械]