本文選題：激光測距　切入點：信號發(fā)生　出處：《北京化工大學》2015年碩士論文

【摘要】：由于激光具有亮度高、單色性好、方向性好和相干性好等優(yōu)點,激光測距技術(shù)不僅成為空間探測的重要技術(shù),還在大地勘測、振動檢測、液位測量等領(lǐng)域獲得推廣。目前,國內(nèi)外常用的激光測距儀主要有相位式和脈沖式兩種。其中,相位式激光測距儀僅限于用在對精度要求比較高的近距離測量場合,脈沖式激光測距儀僅限于應(yīng)用在對精度要求低的遠距離測量場合。針對這一現(xiàn)象,本文對一種脈沖式與相位式相結(jié)合的激光測距系統(tǒng)進行了研究。本文概述了激光測距技術(shù)的國內(nèi)外研究現(xiàn)狀,并對四種常用的激光測距技術(shù)進行了介紹。提出了一種將脈沖式測量法與相位式測量法相結(jié)合的具體方法。擬定出激光測距系統(tǒng)的總體設(shè)計方案,將系統(tǒng)分為信號發(fā)生、信號接收、混頻和鑒相四個模塊,完成各模塊的電路原理圖設(shè)計與軟件實現(xiàn)。其中,信號發(fā)生模塊能分別產(chǎn)生15 MHz脈沖信號和14.99 MHz本振正弦信號；信號接收模塊能實現(xiàn)將15 MHz光波信號轉(zhuǎn)換為電脈沖信號；混頻模塊的功能為將初始脈沖信號和回波脈沖信號分別與本振信號作差頻處理,得到兩路10 KHz余弦信號；鑒相模塊最終完成對兩路信號的采集與處理,并通過LCD顯示測量結(jié)果。對信號發(fā)生模塊的考爾濾波電路、信號接收模塊的反向高壓發(fā)生電路與電壓比較濾波電路、混頻模塊的低通濾波電路和鑒相模塊的CIC濾波電路進行模擬仿真分析。分析結(jié)果表明,考爾濾波電路對于DDS輸出的信號噪聲有很好的濾除效果；反向高壓發(fā)生電路的NE555時鐘芯片能輸出占空比為87.5%的10.3 KHz脈沖信號,電路可輸出149.02 V穩(wěn)定直流高壓；混頻模塊的低通濾波電路可得到10 KHz目標信號；鑒相模塊的CIC濾波電路對乘法器輸出的倍頻信號具有很好的濾除效果。對高壓發(fā)生電路進行了實驗研究,設(shè)計并完成將信號發(fā)生模塊直接與鑒相模塊相連的測試實驗。實驗結(jié)果表明,高壓發(fā)生電路輸出直流電壓能達到145 V。測試實驗電路引入的系統(tǒng)測量誤差最大約0.94 mm。對系統(tǒng)誤差進行分析,得到在高壓發(fā)生電路使用電磁屏蔽罩,在接收模塊電路追加設(shè)計一個相位補償電路的改進方法。
[Abstract]:Because laser has the advantages of high brightness, good monochromatic, good directivity and good coherence, laser ranging technology has not only become an important technology in space exploration, but also has been popularized in the fields of geodetic survey, vibration detection, liquid level measurement and so on.At present, there are two kinds of laser rangefinders at home and abroad: phase type and pulse type.The phase laser rangefinder is only used in the close-range measurement where the precision requirement is high, and the pulse laser rangefinder is only used in the remote measurement field where the precision requirement is low.Aiming at this phenomenon, a laser ranging system combining pulse and phase is studied in this paper.In this paper, the research status of laser ranging technology at home and abroad is summarized, and four commonly used laser ranging techniques are introduced.A method of combining pulse measurement with phase measurement is proposed.The overall design scheme of laser ranging system is worked out. The system is divided into four modules: signal generation, signal receiving, frequency mixing and phase detection. The circuit schematic design and software implementation of each module are completed.The signal generation module can generate 15 MHz pulse signal and 14.99 MHz local oscillator sinusoidal signal respectively, and the signal receiving module can convert 15 MHz light wave signal into electric pulse signal.The function of the mixing module is to separate the initial pulse signal and the echo pulse signal from the local oscillator signal to obtain two 10 KHz cosine signals, and the phase discrimination module finally completes the acquisition and processing of the two signals, and displays the measurement results by LCD.The paper simulates and analyzes the Kaul filter circuit of the signal generation module, the reverse high voltage generation circuit and the voltage comparison filter circuit of the signal receiving module, the low pass filter circuit of the mixing module and the CIC filter circuit of the phase discriminating module.The analysis results show that the Kauer filter circuit has a good filtering effect on the noise of the DDS output signal, the NE555 clock chip of the reverse high voltage generating circuit can output 10.3 KHz pulse signal with duty cycle ratio of 87.5%, and the circuit can output 149.02 V stable DC high voltage.The low pass filter circuit of mixing module can get 10 KHz target signal, and the CIC filter circuit of phase detection module has good filtering effect on the frequency doubling signal output by multiplier.The high voltage generating circuit is studied experimentally, and the test experiment of connecting signal generation module directly with phase detection module is designed and completed.The experimental results show that the output DC voltage of the circuit can reach 145 V.The maximum measurement error of the system introduced by the experimental circuit is about 0.94 mm.By analyzing the system error, an improved method of using electromagnetic shield in high-voltage generating circuit and designing a phase compensation circuit in receiving module circuit is obtained.
【學位授予單位】：北京化工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN249

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本文編號：1726247