發(fā)布時間：2018-01-12 06:04

  本文關(guān)鍵詞：激光小信號寬帶放大器設(shè)計(jì)與實(shí)現(xiàn)　出處：《華中師范大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 三維激光掃描儀 激光測距 寬帶放大器 噪聲 帶寬

【摘要】：與其他測距技術(shù)相比,激光測距具有抗干擾能力強(qiáng)、測距精度高、測量距離遠(yuǎn)和能全天候工作等諸多優(yōu)點(diǎn),獲得了廣泛應(yīng)用。近年來,以激光測距技術(shù)為基礎(chǔ)的三維激光掃描儀,正在推動移動測量、三維實(shí)景地圖等領(lǐng)域的快速發(fā)展,在國民經(jīng)濟(jì)和國防建設(shè)中具有非常重要的意義。作為三維激光掃描儀的核心部件之一的前端模擬電路,用于將激光小信號進(jìn)行放大,其性能直接影響距離測量的精度和測距量程。前端模擬電路需要攻克以下幾個關(guān)鍵技術(shù)難題：寬動態(tài)范圍,模擬電路需具備較寬的動態(tài)范圍,以適應(yīng)不同距離、不同反射率目標(biāo)的測距需求；大放大倍數(shù),對于遠(yuǎn)距離和低反射率的反射物,需要大的放大倍數(shù)對微弱脈沖信號進(jìn)行有效放大；寬帶寬,三維激光掃描儀采用的激光器單個脈沖的脈寬在ns級,能量分布的帶寬很寬；低噪聲,降低噪聲,提高信噪比,提高測距的精度。本文針對上述技術(shù)難題開展研究,首先分析了激光脈沖回波信號的特點(diǎn),結(jié)合測距量程的要求,得出了本文激光小信號寬帶放大器的設(shè)計(jì)技術(shù)指標(biāo)；然后針對寬動態(tài)范圍的激光測距要求,提出了多通道的設(shè)計(jì)方案；最后分模塊詳細(xì)闡述了激光小信號寬帶放大器的設(shè)計(jì)。本文采用高響應(yīng)速度和高靈敏度的銦鎵砷APD作為前端光電探測器件,以跨阻放大器作為電路結(jié)構(gòu),設(shè)計(jì)了寬帶寬、高靈敏度和低噪聲的光電轉(zhuǎn)換電路,放大倍數(shù)達(dá)69.5dB。為進(jìn)一步減小噪聲,采用過渡帶特性最好的橢圓濾波器,完成了9階120MHz帶寬的橢圓濾波器設(shè)計(jì)；以高速電流反饋型差分運(yùn)算放大器作為放大器主要器件,采用多級級聯(lián)放大的方式,實(shí)現(xiàn)了28dB放大倍數(shù)的寬帶放大器設(shè)計(jì)。經(jīng)實(shí)驗(yàn)驗(yàn)證,本文設(shè)計(jì)的模擬電路方案簡單實(shí)用、體積小,具有120MHz的系統(tǒng)帶寬、97.5dB的總放大倍數(shù)和50mVpp總的系統(tǒng)噪聲,能對各種反射率條件下不同目標(biāo)物體反射回來的微弱激光小信號進(jìn)行有效的放大。經(jīng)測試,其最低激光檢測靈敏度為1.1uW,有效測距量程大于300m,目前己成功應(yīng)用于武漢海達(dá)數(shù)云技術(shù)有限公司首臺自主研發(fā)的高精度三維激光掃描儀中。
[Abstract]:Compared with other ranging technology, laser ranging has strong anti-interference capability, high accuracy, long measurement distance and the advantages of all-weather work, has been applied widely. In recent years, 3D laser scanner using laser ranging technology as the foundation, is to promote the rapid development of mobile measurement, real three-dimensional map and other fields. Has a very important significance in the national economy and national defense construction. As the front one of the core parts of the 3-D laser scanner for analog circuit, amplify the laser small signal, its performance directly affects the precision of distance measurement and measurement range. The front-end circuit need overcome key technical problems as follows: wide dynamic range, analog circuit need to have a wide dynamic range, to meet the different needs of different target distances, ranging reflectivity; high magnification, with long distance and low reflectivity counter Shooting, need large amplification of weak pulse signal amplification; wide bandwidth, using 3D laser scanner laser single pulse width in the ns level, the energy distribution of wide bandwidth; low noise, reduce noise, improve SNR, improve the ranging accuracy. Aiming at the above problem research the paper analyses the characteristics of laser pulse echo signal, combined with the measurement range of requirements, the design of the technical index of laser small signal amplifier; and laser ranging in wide range dynamic requirements, puts forward the design scheme of multi channel; finally the module detailed design of broadband laser small signal amplifier. This paper uses the high the response speed and high sensitivity of InGaAs APD as front photoelectric detector, the transimpedance amplifier circuit is designed as structure, wide bandwidth, high sensitivity and low The noise of the photoelectric conversion circuit, amplification of 69.5dB. in order to reduce the noise further, using elliptic filter transition band. The best, completed the design of 9 order elliptic filter 120MHz bandwidth; with high speed current feedback type differential amplifier amplifier as the main devices, using multistage cascade way, realize the design of broadband amplifier 28dB amplification. After experimental verification, the design of analog circuit is simple and practical, small volume, the system bandwidth is 120MHz, the total magnification and 50mVpp total 97.5dB system noise, of weak laser small signal under the condition of various reflectance of different objects are reflected back effectively enlarged. After the test, the minimum laser detection the sensitivity is 1.1uW, the effective range is more than 300m, has been successfully applied in Wuhan Haida few clouds Technology Co. Ltd. the first independent research and development High precision three-dimensional laser scanner.

【學(xué)位授予單位】：華中師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN722

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本文編號：1412977