摘 要：對(duì)雷達(dá)系統(tǒng)中普遍使用的線性調(diào)頻信號(hào)進(jìn)行時(shí)域頻域分析，介紹了線性調(diào)頻信號(hào)匹配濾波器的時(shí)頻特性，重點(diǎn)計(jì)算和分析了此類信號(hào)經(jīng)匹配濾波壓縮處理的過(guò)程和結(jié)果， 最后對(duì)線性調(diào)頻信號(hào)匹配濾波器輸出過(guò)程進(jìn)行建模，分析了雷達(dá)目標(biāo)回波信號(hào)的接收方法以及經(jīng)過(guò)匹配濾波器后的輸出結(jié)果。

關(guān)鍵詞：匹配濾波器；線形調(diào)頻信號(hào)；回波信號(hào)；脈沖調(diào)制

Research and Simulation of Linear FM Signal Matched Filter

YANG Jian，ZHU Zhongming

(College of Information Engineering，Chengdu University of Technology，Chengdu，610059，China)

Abstract：The linear FM signal for time-frequency commonly used in the radar system in the paper is analysed.It introduces characteristics of linear FM signal matched filter，focuses on compting and analyzing the process and results，which is mainly about key terms such as signal compression matched filtering.Furthermore，modeling the process of final pair of LFM output signal matched filtering.It analyses the method of radar echo signal reception and the output comes from the matched filtering in conclusion.

Keywords：matched filter;linear FM signal;echo signal;pulse modulation

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1 引 言

早期的雷達(dá)信號(hào)，多采用簡(jiǎn)單的矩形脈沖調(diào)制。但隨著對(duì)雷達(dá)性能要求的不斷提高，傳統(tǒng)的簡(jiǎn)單脈沖調(diào)制方式已遠(yuǎn)不能適應(yīng)雷達(dá)發(fā)展的需要，而信號(hào)的調(diào)制形式對(duì)雷達(dá)的性能具有決定性作用，尤其在功率一定的情況下。

線性調(diào)頻信號(hào)是通過(guò)非線性相位調(diào)制獲得大時(shí)寬帶寬積的典型例子，是研究最早、使用最廣泛的脈沖壓縮信號(hào)。這種信號(hào)的突出優(yōu)點(diǎn)是匹配濾波器對(duì)回波信號(hào)的多普勒頻移不敏感，因此線性調(diào)頻信號(hào)是現(xiàn)代雷達(dá)中經(jīng)常采用的信號(hào)波形之一。

當(dāng)前，雷達(dá)系統(tǒng)中，在雷達(dá)距離方程中往往強(qiáng)調(diào)應(yīng)該是信噪比最大，所以需要使用匹配濾波器將雷達(dá)接收機(jī)輸出端的噪聲功率減至最小。

本文通過(guò)對(duì)線性調(diào)頻信號(hào)頻譜特性的分析，討論目標(biāo)的回波通過(guò)匹配濾波器之后頻譜特性的變化，更加詳細(xì)地理解此類信號(hào)的特點(diǎn)，對(duì)實(shí)際應(yīng)用具有一定的參考價(jià)值。

2 線性調(diào)頻信號(hào)及其頻譜

2.1 線性調(diào)頻信號(hào)的產(chǎn)生