共址干扰下的车载跳频电台误码率计算与分析

针对车载HF跳频电台的共址干扰问题进行了较为全面和深入的研究.首先对共址平台和天线耦合度进行了分析,并通过建立有线实验平台和理论模型,深入研究了功率、频率、误码率等参数之间的相互关系.在此基础上,通过分析HF组网的约束条件,建立了综合共址干扰、跳频、组网等因素的误码率计算模型.实例分析表明,模型为评估系统性能和配置电台工作参数提供了理论依据.     

车载通信直扩电台共址干扰分析与抑制方法

对车载通信直扩电台的主要共址干扰类型进行分析,并指出共址干扰对车载通信直扩电台的影响。以共址干扰判据为基础,对共址干扰与电台上装规模和通信距离的关系进行了量化分析。在此基础上提出解决共址干扰的具体措施．为多部直扩电台共址配置时的电磁兼容问题和抗共址干扰能力的提升提供可靠的理论依据。     

跳频通信干扰问题研究

跳频通信具有优良的反侦查抗干扰能力，因而在军事通信方面得到了广泛应用。本文针对性的研究了跳频通信的干扰问题，分别从时域、空域、频域和能域四个方面分析了干扰的效能，为进一步研究新式跳频电台的干扰提供一些参考。     

基于Tansig函数的自适应同址干扰抵消算法

针对跳频电台间同址干扰的特点一干扰强和射频干扰信号的时变特性,提出基于非线性Tansig函数的变步长LMS算法,给出其迭代公式并分析该算法性能.对该算法在自适应跳频同址干扰抵消中的性能进行仿真,仿真结果表明该算法对于非平稳强干扰系统具有很好的收敛速度、收敛精度和稳定性,且其计算量较小,能满足实时非平稳强干扰的自适应抵消的要求.     

GMSK通信短波电台带内干扰抑制技术研究

针对通信电台易受电磁干扰的问题,采用了基于自适应干扰对消的干扰抑制方法来解决带内干扰。主要介绍了自适应干扰对消原理以及高斯最小频移键控(GMSK)调制原理,通过在simulink下建立短波跳频电台模型以及加入对消器的电台模型,仿真中改变干扰类型,得出了对消前后白噪声、定频干扰和梳状干扰在不同信噪比下的误码率。仿真结果表明,梳状干扰对通信性能的影响较为明显,定频干扰和白噪声干扰次之;在加入自适应对消器后,干扰抑制效果显著。     

基于Simulink的跳频通信系统抗干扰性能分析

跳频通信方式是军事通信的主要手段,保证跳频通信系统的正常工作十分重要,研究了跳频通信的几种常见干扰样式,用Simulink仿真工具搭建跳频通信系统仿真平台,并模拟几种常见干扰源,包括宽带或部分频带阻塞干扰、梳状阻塞干扰及跟踪干扰。分别在信道注入各种干扰,得到相应的误码率曲线,分析并评价其抗干扰性能。     

跳频干扰有效区研究

通过分析对跳频电台跟踪瞄准式干扰的原理,得到了影响干扰效果的几个因素,从这几个因素入手经过理论计算确定了对跳频通信进行干扰时有效区的分布,讨论了它们之间的关系。     

通信车辆电磁兼容问题研究

针对通信车辆底盘电气系统对车载跳频电台干扰问题进行研究。在对车辆底盘电气系统分析的基础上,通过信道模拟法,分析了车辆底盘电气系统对车载通信设备干扰途径,主要是通过辐射发射方式耦合到车载跳频电台天线,增大背景噪声,降低跳频电台接收机灵敏度,减小电台通信距离。提出了快速和有效的通信底盘电气系统对车载跳频电台干扰量测试与整改验证方案,并采取简单及有效的电磁兼容整改措施。经检验,底盘电气系统对车载跳频通信设备的干扰量由原来3~4 d B降至0.3 d B以下,即由原来开发动机时车载跳频电台只能通信15 km,改善为在开发动机时仍能通信23.64 km,满足战术通信指标要求。     

对跳频通信系统干扰方法的研究

通过对跳频通信系统抗干扰性能的分析，提出了我海军跳频通信干扰系统的发展原则，探讨了有效干扰跳频通信系统的方法，包括对跳频通信同步系统和跳频通信信号的干扰方法。     

浅谈跳频通信技术的应用与发展

跳频通信是扩频通信的一个分支,它具有抗干扰性强的突出优点,是对抗无线电干扰的有效手段,在军事领域具有很高的应用前景。从上世纪第一部跳频电台问世至今,跳频通信倍受世界各国青睐,使跳频通信技术的发展势头锐不可挡。世界各国军队开始普遍装备跳频电台,同时跳频通信又被广泛拓宽并应用到民用领域,使跳频通信技术有了长足发展。     

基于瞬时频率畸变特性的FSK电台指纹特征提取

为解决FSK电台个体识别问题,需要从辐射源信号上提取特征构成辐射源指纹。通过分析构成FSK电台的各个模块的畸变特性,阐明了FSK电台指纹产生机理,建立了基于瞬时频率的指纹信号模型,并根据信号模型设计了基于辅助参数的最小二乘算法以完成FSK频率畸变特性参数的估计,从而构建指纹特征完成对FSK电台的识别。对仿真信号和实际信号的识别测试试验表明,该算法具备辐射源个体识别能力,对实际环境下的4个FSK电台的识别率大于96%,优于双谱类方法。     

基于多通道最小均方算法的多发单收同车电台射频干扰对消

战术指挥车内多部电台同时工作,发射电台将对接收电台产生严重的互扰。针对上述问题,该文提出基于多通道最小均方算法(MCLMS)的多发单收同车电台射频干扰对消方法。首先,分析同车电台N 发M 收情况可分离为M个N发单收场景的叠加,进而建立多发单收射频干扰对消模型。在此基础上,提出基于MCLMS算法的射频干扰对消方法,并理论分析该对消方法的性能,推导得出互扰对消比(MICR)与发射电台数目N、收敛因子\begin{document}$\mu $\end{document}之间的闭合数学表达式。最后,通过仿真验证了理论结果的正确性,表明该方法能够有效抑制同车发射电台对接收电台的互扰影响,增强指挥车电磁兼容性。     

Dynamic Frequency-Band Reallocation and Allocation: from Satellite-Based Communication Systems to Cognitive Radios

This paper discusses two approaches for the baseband processing part of cognitive radios. These approaches can be used depending on the availability of (i) a composite signal comprising several user signals or, (ii) the individual user signals. The aim is to introduce solutions which can support different bandwidths and center frequencies for a large set of users and at the cost of simple modifications on the same hardware platform. Such structures have previously been used for satellite-based communication systems and the paper aims to outline their possible applications in the context of cognitive radios. For this purpose, dynamic frequencyband allocation (DFBA) and reallocation (DFBR) structures based on multirate building blocks are introduced and their reconfigurability issues with respect to the required reconfigurability measures in cognitive radios are discussed.     

多台站同址干扰分析及仿真

针对当前同一平台上多个台站之间产生干扰的问题,研究了同址干扰产生的干扰类型以及干扰原理。对同址干扰的典型实例进行了仿真实现,并对干扰的仿真结果进行了分析。给出了消除同址干扰的措施并对台站的配置及天线的选取和合理布局提出了科学的建议。经论证,多部装置装配在同一平台在理论上是可行的,为多部电台同址配置时的电磁兼容问题和抗同址干扰能力的提升提供可靠的理论依据。     

职业对讲机台站减少头部SAR测试的注意事项

本文提供了对讲机台站减少SAR测试的指导,文中提供的程序是基于对制造商和测试实验室如何测试对讲机台站和相关配件的测试调查而制定的.职业对讲机台站使用通常有多个天线、电池、身体佩戴和音频配件,一些台站大量多种多样的配件使SAR测试配置的数量也变得非常多,测试结果也是成千上万的组合.     

Ultraviolet radios beam to life

The U.S. military has been chasing ultraviolet (UV) communication for decades. Now researchers say radios that communicate using UV light are finally within reach. Working with the Army Research Lab (ARL) in Adelphi, Md., these researchers are mapping out the steps needed to commercialize UV radios. They?ve reached the last piece of the puzzle: untangling the poorly understood, extraordinarily complex way ultraviolet light scatters. If they can do that, they will have unlocked the secret to a new form of non-line-of-sight communication.     

Virtual radios

Conventional software radios take advantage of vastly improved analog to digital converters (ADCs) and digital signal processing (DSP) hardware. Our approach, which we refer to as virtual radios, also depends upon high performance ADCs. However, rather than use DSPs, we have chosen to ride the curve of rapidly improving workstation hardware. We use wideband digitization and then perform all of the digital signal processing in user space on a general purpose workstation. This approach allows us to experiment with new approaches to signal processing that exploit the hardware and software resources of the workstation. Furthermore, it allows us to experiment with different ways of structuring systems in which the radio component of communication devices is integrated with higher-level applications. This paper describes the design and performance of an environment we have constructed that facilitates building virtual radios and of two applications built using that environment. The environment consists of an input/output (I/O) subsystem that provides high bandwidth low latency user-level access to digitized signals and a programming environment that provides an infrastructure for building applications. The applications, which exemplify some of the benefits of virtual radios, are a software cellular receiver and a novel wireless network interface     

Performance evaluation of multiple access spread spectrum systemsin the presence of interference

A simplified version of the Lee-Smith algorithm (W.C. Y. Lee and H.L. Smith, ibid., vol. VT-32, p.177-90, May 1983) is proposed for computing the probability of outage and the bit error rate (BER) due to autointerference in multiple-access spread-spectrum radio systems. The model assumes a pair of transmitting and receiving radios in a region where there are other radios operating in the same band. Each radio is characterized by its own spatial distribution, transmitting power, activity coefficient (denoting the percentage of time the radio is active), antenna height, and a set of carrier frequencies. The probability of outage with respect to the log-normal field-strength attenuation is derived assuming that the probability of having more than one interferer is very low. To allow maximal flexibility, the spatial, carrier frequency, and activity distributions are computer simulated for each radio. As an example of applying the method, the probability of error of an asynchronous frequency-hopping (FH) and a hybrid frequency-hopping/direct sequence (FH/DS) modulation schemes in environments with thousands of radios is reported