摘要无线电近感探测器对目标进行探测是通过发射电磁波，电磁波遇到目标,再经目标反射后被探测器接收到，对回波信号经过相应处理来提取目标特征的。对相关目标的识别主要有提取目标的距离、速度、目标特征等方面信息。在无线电探测器的各种体制中，为了准确的提取出目标的相关特征，最主要的是对目标的回波信号进行信号处理。63913

调频多普勒无线电定距系统发射调频连续波，通过对发射信号与回波信号的差频进行信号处理，从而得出目标的速度信息以及距离信息。调频方式主要包括:正弦波调频、三角波调频和锯齿波调频。其特点是：定距精度高、接收机灵敏度高、工作电压低、距离选择性好、结构简单、抗干扰能力强等，因此对其的研究具有重要的理论和现实意义。

本文主要对正弦波调频定距系统进行了研究：首先分析了差频信号在静止和运动目标情况下的频谱，其次推导了系统中发射信号和回波信号混频后得到的差频信号的时域和频域数学表达式，在此基础上提出了定距方案，接着使用Matlab/Simulink软件平台进行了整个系统的仿真，对定距方案进行了论证。

毕业论文关键词  调频多普勒，正弦波，差频信号，信号处理

毕业设计说明书（论文）外文摘要

Title    Sine FM proximity detection system analysis and   simulation                                       

Abstract FM Doppler radio of the fixed distance system transmits frequency modulated continuous wave signal, through the signal processing of the difference frequency signal which is gotten by mixing the transmitted signal and the received signal, the speed and distance information of the target can be valued. FM modes include: sine wave FM, triangle and sawtooth FM. Its characteristics are: high fixed distance precision, high receiver sensitivity, low working voltage, good distance selectivity, simple structure and strong anti- interference ability, so the study into it has important theoretical and practical significance.

In this paper,sine wave frequency modulation of the fixed distance system is mainly studied: firstly, the spectrum of the difference frequency signal under the circumstances of both stationary and moving targets is analyzed, then, the mathematical expressions of the difference frequency signal which is gotten by mixing the transmitted signal and the received signal in both time and frequency domain are deduced, on this basis, the fixed distance scheme is proposed, then use the Matlab/Simulink software platform for the whole system simulation so as to demonstrate the fixed distance scheme.

Keywords  FM Doppler, sine wave, the difference frequency signal, signal processing, compare, advantages and disadvantages

 目  录

1  引言 1

1.1选题背景 1

1.2调频定距系统发展 1

1.3仿真软件平台介绍 2

1.4论文工作及内容安排 3

2  调频定距系统 4

2.1概述 4

2.2调频定距系统原理 4

2.2.1 正弦波调频的差频与弹目距离的关系 5

2.2.2 正弦波调频的差频信号分析 7

2.3本章小结 11

3  调频多普勒定距系统 12

3.1概述