噪声调频信号对宽带线性调频雷达的干扰机理

研究了噪声调频信号中调制噪声方差及带宽的选择对宽带线性调频匹配滤波器的影响。通过观察噪声调频信号通过线性调频匹配滤波器之后的时域输出包络,分析了其起伏特性,推导出了在最大包络起伏指标下的调制噪声最优带宽应该为发射线性调频信号的时宽的倒数量级。同时,通过误差分析表明:要在实际中达到此干扰最优带宽,对侦察接收机的指标要求无需过高。     

对线性调频脉压雷达的灵巧噪声干扰研究

针对传统噪声在干扰LFM脉冲压缩雷达时干扰功率利用率不高的问题,提出一种灵巧噪声干扰实现方法。该方法将DRFM存储的雷达发射信号与噪声信号相卷积得到灵巧噪声信号,这种信号干扰能量利用率高,能产生压制性和欺骗性双重干扰效果。文章从理论分析和仿真实验角度证明了它能有效干扰LFM脉冲压缩雷达,且性能明显优于射频噪声干扰。     

噪声干扰中调频干扰的时序建模

噪声调频干扰属于压制式干扰,由于它容易达到宽的干扰带宽,已经成了目前噪声干扰的主要形式。通过时域自相关法对噪声调频干扰进行频谱分析,简要说明其干扰特性和中放输出的干扰特性,最后建立噪声调频干扰信号及其通过中放后的时间序列模型。     

噪声干扰对线性调频脉冲压缩滤波器的干扰效果分析

以压缩滤波器归一化输出包络的主瓣脉宽以及最大旁瓣为指标，分析多种噪声干扰样式对压缩滤波器的干扰效果。     

被动单脉冲导引头对噪声调频干扰的角跟踪

研究了被动振幅和差单脉冲导引头对宽带噪声调频干扰源的响应和跟踪特性，并重点研究了主波束内存在两个非相干干扰源的情况下导引头的角跟踪规律，最后提出了在存在两个噪声调频干扰时导引头提取角信号的一种方法，计算机仿真验证了该方法的正确性和有效性。     

对逆合成孔径雷达噪声调频预加重干扰的研究

研究了对ISAR的一种相干干扰方式--噪声调频预加重干扰。相对于常规的非相干噪声调频干扰,噪声调频预加重干扰可以获得一定的处理增益,从而节省干扰功率。     

伪码体制引信的抗噪声调频干扰性能分析

在介绍伪码体制引信的工作原理和噪声调频干扰原理的基础上,详细推导了伪码调相引信和伪码调相与PAM复合引信在噪声调频干扰环境下的总信干比增益,并仿真实现了伪码体制引信的工作过程,得出的仿真总信干比增益与理论的推导值接近。理论和仿真结果及输出的相关值证明,一般而言,伪码体制引信具有较强的抗噪声调频干扰能力。     

噪声调频干扰对脉冲压缩雷达的影响分析

噪声调频干扰是一种广泛使用的噪声干扰技术,通过分析噪声调频干扰信号产生原理,用Matalb仿真了在单目标和多目标情况下,噪声调频干扰对脉冲压缩雷达的影响。给出的仿真结果表明,噪声调频干扰对LFM脉冲压缩雷达具有较强的干扰作用。     

混沌噪声调频信号对UWB—SAR／ISAR成像的干扰

建立了n-Way Bernoulli混沌调频信号模型,分析了UWB-SAR/ISAR的成像特点,提出利用Bernoulli混沌噪声调频信号对UWB-SAR/ISAR进行成像干扰。仿真结果表明,利用Bernoulli混沌噪声调频信号干扰UWB-SAR/ISAR是可行的。     

The response of an automatic phase control system to FM signals and noise

An Automatic Phase Control (APC) System is analyzed in order to determine its response to frequency modulated signals, and narrow-band Gaussian noise. Emphasis is placed on the system's response to signals having "ramp" type FM. The response of the APC System to an FM signal is obtained using a perturbation and a piecewise linear technique. The response of the system to noise is obtained using an iteration technique. The complete response to an FM signal and noise is then discussed using an iteration technique and extending the results previously obtained.     

卫星通信干扰信号的识别研究

文章就几种常见的卫星干扰信号,对其进行MATLAB仿真实验,依据不同干扰信号的特点,从其时域、频域等方面分析各种干扰类型的分类依据,提取、构造各种干扰类型的有效识别参数,采用基于统计判决的模糊模式识别算法,进行仿真分析。实验表明,本文提取构造的参数得到了较高的识别率,为干扰信号的识别提供理论基础,具有重要意义。     

Robust DFT-based filtering of pulse-like FM signals corrupted by impulsive noise

Filtering of pulse-like FM signals with varying amplitude corrupted by impulse noise is considered. The robust DFT calculated for overlapped intervals is used for this aim. This technique is proposed in order to decrease amplitude distortion of output signals that can be introduced by the robust DFT calculated within a wide interval including possible zero-output. The proposed algorithm is realized through the following steps. In the first stage, the robust DFT is calculated for the intervals. Filtered signals from the intervals are obtained by applying the standard inverse DFT for the robust DFTs applied to input data. In the second stage, results for different overlapped intervals are combined using the appropriate order statistics. In addition, an algorithm inspired by the intersection of the confidence intervals rule is used for adaptive selection of the interval width in the robust DFT. Algorithm accuracy is tested on numerical examples. Computational complexity analysis is also provided.     

A novel clipping technique for filtering FM signals embedded in intensive noise

A novel adaptive clipping technique for filtering a constant amplitude frequency modulated (FM) signal embedded in non-Gaussian noise is proposed. It is based on the analysis and processing of the estimate of probability density function of a FM signal realization. As a result, modifications of two robust estimators of FM signal amplitude are proposed. It is shown that these estimators can be used for Gaussian and non-Gaussian heavy-tail environments. The proposed clipping technique can exploit one or another obtained robust estimate of the signal amplitude for adaptive setting a threshold. Analysis of signal estimate accuracy for different noise environments is carried out. Comparative analysis of the obtained methods and known approaches based on scanning window nonlinear filtering and optimal robust L-DFT form is performed. It is demonstrated that the usage of clipping-based technique leads to the considerable improvement of the FM signal filtering efficiency in comparison to the aforementioned known approaches for different noise environments and a wide range of input SNR values.     

Modulation-transfer noise effects among FM and digital signals in memoryless nonlinear devices

When two or more frequency-modulated and/or digital carriers of various sizes and modulation formats are transmitted through a common memoryless nonlinear device with AM/AM and AM/PM characteristics such as a traveling-wave tube amplifier, interactions among the carriers will occur. One of the impairments caused by these interactions results in modulation-transfer noise effects. In particular, in satellite communications, depending on the manner multicarrier transponders are used, the modulation-transfer impairment manifests itself under various forms and subjective interference effects. This tutorial-review paper presents an introduction to this type of impairment, methods of analysis and examples, and measurement results. General practical guidelines are suggested for controlling these effects.     

压制干扰条件下预警雷达探测范围研究

首先分析了战场复杂电磁环境的基本概念,简要介绍了典型的电子战飞机。考虑电子信息系统在复杂电磁环境下面临的威胁,分析了噪声压制性干扰下的雷达干扰模型。对雷达在单干扰机和双干扰机作用情况下的作用范围进行仿真,最后给出了仿真结果。     

一种新的合成孔径雷达压制干扰方法

该文提出一种新的合成孔径雷达(SAR)用压制干扰方法。讨论了这种干扰方法对合成孔径雷达图像的干扰效果。从SAR系统信干比增益和系统干扰功率增益出发,与传统的噪声调制干扰方法进行了比较,并给出了仿真结果。