【摘要】：光纖空氣聲波傳感器相對于傳統(tǒng)的電麥克風具有靈敏度高,測量動態(tài)范圍廣,抗干擾能力強的優(yōu)點,滿足在環(huán)境條件惡劣的情況下,對聲波信號高質(zhì)量檢測,目前對光纖聲波傳感器的研究已成為光纖傳感領(lǐng)域的研究熱點之一。本文針對基于法布里-珀羅干涉型結(jié)構(gòu)的光纖麥克風,對其解調(diào)方法和解調(diào)性能等方面進行了研究,主要內(nèi)容如下：1.詳細分析理想相位生成載波(Phase Generated Carrier,簡稱PGC)算法,利用Simulink仿真工具,驗證算法的可行性。確定調(diào)制頻率、采樣率、濾波器過渡帶寬與解調(diào)動態(tài)范圍之間的關(guān)系,并通過大量數(shù)據(jù)仿真,驗證關(guān)系的正確性。2.針對工程應(yīng)用中,采用DFB(Distributed Feed Back)激光器的光頻內(nèi)調(diào)制方案,利用理想的PGC解調(diào)方法,解調(diào)信號出現(xiàn)多次諧波問題。經(jīng)過分析,提出利用載波二倍和三倍載波頻率來解調(diào)信號的改進方案,消除多次諧波。另外,通過相位補償,解決系統(tǒng)延時對解調(diào)信號的影響。在多頻解調(diào)情況下,驗證解調(diào)信號滿足群延時特性。3.制作光纖麥克風解調(diào)系統(tǒng)硬件電路,編寫FPGA(Field Programmable Gate Array)底層驅(qū)動程序和DSP(Digital Signal Processing)算法。激光器驅(qū)動電路對激光器的工作電流和溫度嚴格限制,保護激光器不受損壞。核心控制電路采集數(shù)據(jù)、進行算法處理、輸出音頻信號,嚴格控制時序,實時解調(diào)。4.對光纖麥克風解調(diào)系統(tǒng)的各方面性能進行測試,測得音頻輸出信號系統(tǒng)線性響應(yīng)度良好,線性響應(yīng)誤差為0.21%；在3kHz-10kHz范圍內(nèi),系統(tǒng)頻率響應(yīng)誤差小于3dB;系統(tǒng)在1kHz處,能檢測的最小聲壓為2mPa,即-54dB@1kHz。實驗結(jié)果表明,此套麥克風信號解調(diào)系統(tǒng)能滿足基本的聲波信號測量要求。
[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.
【學位授予單位】：大連理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN253;TN641

【參考文獻】

相關(guān)期刊論文 前3條

1 徐海英,蔣永梁,王麗,劉英,高杰,吳宗漢;光纖麥克風傳感探頭的設(shè)計研究[J];傳感技術(shù)學報;2004年04期

2 徐秀芳,胡曉東;半導體激光器的功率穩(wěn)恒控制技術(shù)[J];光子學報;2001年06期

3 王代華;黃海;;光纖傳感器用半導體激光器光頻調(diào)制驅(qū)動電源[J];激光雜志;2011年01期

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本文編號：2282197