數字激光告警系統探測接收前端設計

鄭博仁　張　欣

摘 要：探測接收前端是激光告警系統的關鍵部件，針對數字激光告警系統設計激光脈沖探測接收前端。采用寬帶、高增益、低噪聲的跨導放大方式實現了對最小來襲激光脈沖產生的10 nA,10 ns的微弱窄脈沖電流的放大，采用放大器飽和方式實現信號的整形，把來襲激光脈沖轉換、放大成數字系統能處理的數字脈沖，脈沖寬度代表作用能量大小。前端最小可檢測來襲激光信號能量達1 μW，動態范圍達100 dB。該寬帶低噪聲跨導放大電路很好地處理了電容對窄脈沖的影響，具有帶寬寬(500 MHz)，成本低的特點，為放大微弱的ns級及以下的窄脈沖電流信號提供一個很好的寬帶方案。該設計結構簡單、成本低廉、易于維護，不僅可用于激光來襲探測，還可用于激光安防系統等。

關鍵詞：探測接收前端;告警系統;脈沖放大;跨導;放大電路

中圖分類號：TP274 文獻標識碼：B 文章編號：1004－373X(2009)04－175－03

Design of Detecting Receive Front－end for Digital Laser Warning System

ZHENG Boren1,ZHANG Xin2

(1.School of Information Science and Engineering,Chongqing Jiaotong University,Chongqing,400074,China;

2.South West Institution of Physics,Chengdu,610054,China)

Abstract：Detecting receive front－end is a key unit of laser warning system.In the design,a broadband,high gain,and low noise transimpedance amplifier to amplify the least pulse current 10nA,10 ns by the incident laser is used,and a saturation of amplifier to regulate the large signal is employed,which transforms the raid laser signal into digital pulse.The digital pulse width shows the incident laser energy and can be processed by digital system.As a result,a 1 μW of the minimum raid laser energy can be detected,and 100 dB detecting dynamic range be got.The transimpedance broadband amplifier has been deal with the capacitors′ behave to the narrowband current rightly,has a 500 MHz band,it′s a good and less－cost example for amplifying ns level feeble current pulse.The design has characters of simple structure and easy maintenance,can be restructured in civil laser security system.

Keywords：detecting receive front－end;warning system;pulse amplify;transimpedance;amplify circuit

0 引 言

激光技術經過幾十年的發展，激光武器已從理論走向實踐。激光武器的大量出現帶來了日益嚴峻的威脅，激光告警設備對激光來襲的探測與預報是激光對抗的基本手段。如何從復雜的環境下探測判斷激光來襲信號是告警系統面臨的首要任務。隨著數字技術的發展，處理速度的不斷提高，采用數字技術如FPGA等來處理告警信號成為可能。

文章針對數字激光告警系統而設計的探測接收前端，主要目的是探測一定波段的來襲激光信號，具有高的靈敏度，可探測的最小激光能量達到1 μW,動態范圍達到100 dB。……