法布里—珀罗干涉型光纤麦克风PGC解调技术研究
发布时间：2018-10-19 19:57
【摘要】：光纤空气声波传感器相对于传统的电麦克风具有灵敏度高,测量动态范围广,抗干扰能力强的优点,满足在环境条件恶劣的情况下,对声波信号高质量检测,目前对光纤声波传感器的研究已成为光纤传感领域的研究热点之一。本文针对基于法布里-珀罗干涉型结构的光纤麦克风,对其解调方法和解调性能等方面进行了研究,主要内容如下：1.详细分析理想相位生成载波(Phase Generated Carrier,简称PGC)算法,利用Simulink仿真工具,验证算法的可行性。确定调制频率、采样率、滤波器过渡带宽与解调动态范围之间的关系,并通过大量数据仿真,验证关系的正确性。2.针对工程应用中,采用DFB(Distributed Feed Back)激光器的光频内调制方案,利用理想的PGC解调方法,解调信号出现多次谐波问题。经过分析,提出利用载波二倍和三倍载波频率来解调信号的改进方案,消除多次谐波。另外,通过相位补偿,解决系统延时对解调信号的影响。在多频解调情况下,验证解调信号满足群延时特性。3.制作光纤麦克风解调系统硬件电路,编写FPGA(Field Programmable Gate Array)底层驱动程序和DSP(Digital Signal Processing)算法。激光器驱动电路对激光器的工作电流和温度严格限制,保护激光器不受损坏。核心控制电路采集数据、进行算法处理、输出音频信号,严格控制时序,实时解调。4.对光纤麦克风解调系统的各方面性能进行测试,测得音频输出信号系统线性响应度良好,线性响应误差为0.21%；在3kHz-10kHz范围内,系统频率响应误差小于3dB;系统在1kHz处,能检测的最小声压为2mPa,即-54dB@1kHz。实验结果表明,此套麦克风信号解调系统能满足基本的声波信号测量要求。
[Abstract]:Compared with the traditional electric microphone, the fiber optic air acoustic sensor has the advantages of high sensitivity, wide dynamic range of measurement and strong anti-interference ability. At present, the research of optical fiber acoustic sensor has become one of the research hotspots in the field of optical fiber sensing. In this paper, the demodulation method and demodulation performance of fiber optic microphone based on Fabry-Perot interference structure are studied. The main contents are as follows: 1. The ideal phase generation carrier (Phase Generated Carrier, (PGC) algorithm is analyzed in detail. The feasibility of the algorithm is verified by Simulink simulation tool. The relationship between modulation frequency, sampling rate, filter bandwidth and demodulation dynamic range is determined, and the correctness of the relationship is verified by a large number of data simulations. 2. In view of the engineering application, the problem of multiple harmonics in demodulation signal is caused by adopting the optical intracavity modulation scheme of DFB (Distributed Feed Back) laser and using the ideal PGC demodulation method. After analysis, an improved scheme of demodulating signals with double and triple carrier frequencies is proposed to eliminate multiple harmonics. In addition, the effect of system delay on demodulation signal is solved by phase compensation. In the case of multi-frequency demodulation, it is verified that the demodulation signal meets the group delay characteristics. 3. Make the hardware circuit of fiber optic microphone demodulation system, write FPGA (Field Programmable Gate Array) bottom driver and DSP (Digital Signal Processing) algorithm. The laser drive circuit strictly limits the operating current and temperature of the laser and protects the laser from damage. Core control circuit data acquisition, algorithm processing, output audio signal, strict control of timing, real-time demodulation. 4. The performance of fiber optic microphone demodulation system is tested. The linear responsivity of audio output signal system is good, the linear response error is 0.21, the frequency response error is less than 3 dB in 3kHz-10kHz range, and the system is at 1kHz. The minimum detectable sound pressure is 2mPa-54dB@ 1kHz. Experimental results show that the microphone signal demodulation system can meet the basic requirements of acoustic signal measurement.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN253;TN641
本文编号：2282197
[Abstract]:Compared with the traditional electric microphone, the fiber optic air acoustic sensor has the advantages of high sensitivity, wide dynamic range of measurement and strong anti-interference ability. At present, the research of optical fiber acoustic sensor has become one of the research hotspots in the field of optical fiber sensing. In this paper, the demodulation method and demodulation performance of fiber optic microphone based on Fabry-Perot interference structure are studied. The main contents are as follows: 1. The ideal phase generation carrier (Phase Generated Carrier, (PGC) algorithm is analyzed in detail. The feasibility of the algorithm is verified by Simulink simulation tool. The relationship between modulation frequency, sampling rate, filter bandwidth and demodulation dynamic range is determined, and the correctness of the relationship is verified by a large number of data simulations. 2. In view of the engineering application, the problem of multiple harmonics in demodulation signal is caused by adopting the optical intracavity modulation scheme of DFB (Distributed Feed Back) laser and using the ideal PGC demodulation method. After analysis, an improved scheme of demodulating signals with double and triple carrier frequencies is proposed to eliminate multiple harmonics. In addition, the effect of system delay on demodulation signal is solved by phase compensation. In the case of multi-frequency demodulation, it is verified that the demodulation signal meets the group delay characteristics. 3. Make the hardware circuit of fiber optic microphone demodulation system, write FPGA (Field Programmable Gate Array) bottom driver and DSP (Digital Signal Processing) algorithm. The laser drive circuit strictly limits the operating current and temperature of the laser and protects the laser from damage. Core control circuit data acquisition, algorithm processing, output audio signal, strict control of timing, real-time demodulation. 4. The performance of fiber optic microphone demodulation system is tested. The linear responsivity of audio output signal system is good, the linear response error is 0.21, the frequency response error is less than 3 dB in 3kHz-10kHz range, and the system is at 1kHz. The minimum detectable sound pressure is 2mPa-54dB@ 1kHz. Experimental results show that the microphone signal demodulation system can meet the basic requirements of acoustic signal measurement.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN253;TN641
【参考文献】
相关期刊论文 前3条
1 徐海英,蒋永梁,王丽,刘英,高杰,吴宗汉;光纤麦克风传感探头的设计研究[J];传感技术学报;2004年04期
2 徐秀芳,胡晓东;半导体激光器的功率稳恒控制技术[J];光子学报;2001年06期
3 王代华;黄海;;光纤传感器用半导体激光器光频调制驱动电源[J];激光杂志;2011年01期
，本文编号：2282197
本文链接：https://www.wllwen.com/kejilunwen/dianzigongchenglunwen/2282197.html
