LFM脉冲压缩系统设计技术研究

【作者】 崔鹏；

【导师】 赵惠昌；

【作者基本信息】 南京理工大学 ， 信号与信息处理， 2005， 硕士

【摘要】 论文研究了线性调频(LFM)脉冲信号的特征及其数字压缩技术,进行了理论分析仿真。结合某型号引信系统的技战术指标要求,考虑现代信号处理技术与器件发展,探索了信号产生及其工程实现等问题。 线性调频脉冲信号是一种研究最早、应用最广泛的大时宽带宽积信号,其频谱宽度与脉冲宽度可以独立选取,从而得到较高的测距精度和测速精度。另外,由于它对多普勒效应不敏感,所以处理方便;周期模糊函数作为一种分析雷达性能的工具,主要适用于多周期匹配接收的周期(调制)信号。相对于传统的模糊函数,“周期”的影响表现在模糊图的多普勒轴被压缩,且随着周期数的增加压缩率增大,结果多普勒分辨率增强;基于数字技术的直接数字频率合成(DDS)技术具有分辨率高、频率范围广、相位连续、调谐速度快以及调谐方便等优点,可以方便地产生各种复杂信号,并且可以输出正交信号;相对于直接混频与PLL倍频技术,单边带抑制载波调制可以更好地保留DDS信号的相位噪声低、频率变化快等优点,并且实现也较容易。论文最后结合某型号引信工程研制,以AD9854和AD8346芯片为核心,生成LFM信号并进行单边带调制,进行了系统设计并给出了相应的软、硬件说明。更多还原

【Abstract】 The Linear Frequency Modulation (LFM) pulse compression signal is analyzed, in combination with technical and tactical specification of a certain fuse, this paper researches the generation of LFM signal as well as the engineering design.LFM signal is a kind of big product of bandwidth and timewidth by nonlinear phase modulation. The bandwidth and timewidth LFM signal could be independent choose to obtain good distance resolution and speed resolution. What’s more, LFM signal is insensitive to Doppler frequency shift, which means the signal processing is easy.The periodic ambiguity function (PAF) is a tool for analyzing the performance of a radar system utilizing a periodically modulated signal and a receiver matched to one or several periods thereof. The PAF is a generalization of the periodic autocorrelation function, to the case of non-zero Doppler shift. The PAF of LFM signal shows the Doppler axis is being compressed with direct ratio of number of period, this bring the result that Doppler resolution enhanced.For DDS has Micro-Hertz turning resolution, complete digital control, fast "hopping speed" and phase-continuous frequency hops advantages, system employs AD9854 for LFM signal generation and AD8346 for single sideband modulation. System design on hardware and software are both illustrated.更多还原