作者：陈国平, 王红, 程秋菊

作者单位：重庆邮电大学 电工理论与新技术实验室, 重庆 400065

关键词：数字锁相;相位误差;故障诊断;核电环境

摘要：

该文为改善3种传统锁相检测法相位差不可控的缺点，通过对互相关锁相检测原理的改进，提出一种新型数字移相锁相检测法。在核电环境长距离传输条件下，结合对模拟前端电路的相位误差分析，该检测法将两路具有频率固定延时的数字移相信号代替两路正相关模拟信号，对强噪声中的微弱信号进行相敏检测，根据相关函数的差异性利用低通滤波器实现有用信号信息的提取。在核电厂区90 dB的强噪声环境中，对扬声器进行故障试验测试。结果表明：该数字移相锁相检测法可稳定检测的最低信噪比为-40 dB，最大检测误差为2.1%，可有效克服前端模拟移相误差不可控的缺点，完成扬声器工作状态的检测。

Speakers fault detection based on digital phase-shifting lock-in technology
CHEN Guoping, WANG Hong, CHENG Qiuju
Electrotechnical Theory and New Technology Laboratory, Chongqing University of Post and Telecommunications, Chongqing 400065, China
Abstract: In this paper, in order to improve the uncontrollable factors of the phase difference in the three traditional phase-locked detection methods, a novel digital phase-shifting lock-in detection method was proposed through the principle of improved cross-correlation phase lock-in detection. Firstly, the phase error of the analog front-end circuit under the conditions of long-range nuclear power environment was analyzed in depth. Then, the detection method replaces two positive-correlation analog signals with two digital phase-shifting signals with fixed frequency delay, and performs phase-sensitive detection on weak signals in strong noise. Finally, using a low-pass filter to extract useful signals according to the difference of correlation functions. Speaker fault detection test in a strong noise environment of 90 dB, the results show that the method can detect the lowest SNR of -40 dB, and the maximum detection error is only 2.1%. It effectively overcomes the disadvantages of uncontrollable front-end analog phase-shifting errors, and completed the work status of the speaker detection.
Keywords: digital lock-in;phase error;fault diagnosis;nuclear power environment
2019, 45(6):1-5,23  收稿日期: 2018-06-10;收到修改稿日期: 2018-07-12
基金项目: 重庆市教委自然科学基金（KJ130507）
作者简介: 陈国平(1976-),男,重庆市人,教授,研究方向为毫米波近场成像、嵌入式系统和高性能FPGA并行计算
参考文献
[1] 冯晨, 秦工, 詹昊思, 等. 互相关检测法在微弱信号检测中的应用[J]. 理论与算法, 2016(17):65-66
[2] WANG G, REBOUL S, CHOQUEL J B, et al. Circular regression in a dual-phase lock-in amplifier for coherent detection of weak signal[J]. Sensors, 2017, 17(11):2615
[3] 张林, 董浩斌, 宋恒力. 基于正交锁相放大器的交流电法接收机设计[J]. 中国测试, 2015, 41(9):60-65
[4] ZHANG G, WANG Y. Research on weak signal detection in time domain based on phase locked loop and duffing oscillator[J]. Science Technology & Engineering, 2014, 14(6):13-19
[5] LIU H F, LI B, HE Q X, et al. Development of a digital orthogonal lock-in amplifier and its application in methane detection[J]. Acta Photonica Sinica, 2016, 45(4):18-23
[6] QI C, HUANG Y, ZHANG W, et al. Design of dual-phase lock-in amplifier used for weak signal detection[C]//Industrial Electronics Society, IECON 2016, Conference of the IEEE. IEEE, 2016:883-888.
[7] TANG C, ZHANG M Y, CAO G H, et al. Study of cross-correlation algorithm-based weak signal extraction method for laser alignment of large unit[J]. Acta Armamentarii, 2017, 38(10):2048-2054
[8] WANG Q, ZENG Q N, ZHENG Z H. Research of speech endpoint detection in low SNR environment[J]. Science Technology & Engineering, 2017, 17(21):50-56
[9] DU T, GUAN B, WU A, et al. Dual-band bandpass filter based on quadruple-mode open stub loaded square ring resonator[C]//IEEE International Conference on Signal Processing, Communications and Computing. 2018:1-4.
[10] 李志军, 曾以成. 多功能AB类四象限模拟乘法器[J]. 电子学报, 2011, 39(11):2696-2700
[11] ZHANG Z, CHENG X, YU Y, et al. A fast-transition over-thermal protection circuit[J]. Semiconductor Technology, 2016(1):22-26
[12] MIAO C Z, LIN B Y, DANG J M, et al. Lock-in amplifier for pulse-driven quantum cascade lasers gas detection system[J]. Acta Photonica Sinica, 2016, 45(8):87-92