PLC系统信号干扰与防范措施

结合现场,分析PLC控制系统中信号产生干扰的原因,和可能引起模板故障的因素,并提出相应解决方法.     

A pair of parallel differential magnetic‐field probes with high measurement accuracy and high electric‐field suppression ratio

Magnetic‐field probes can be used for electromagnetic interference measurement of high‐speed circuits. The main magnetic probe performance includes sensitivity, spatial resolution, electric‐field suppression ratio (EFSR), and measurement accuracy. In this article, a pair of differential magnetic‐field probes is proposed to improve measurement accuracy without reducing sensitivity. The proposed differential probes consist of two asymmetric loop probes, which are designed in the same plane and separated by a row of periodic vias. The proposed differential probes are fabricated under PCB process. High accuracy can be achieved by measuring difference between outputs of the two probes. In addition, EFSR can be improved by size optimization of the differential magnetic‐field probes. Simulation and measurement results show the operating bandwidth is from 100 MHz to 12 GHz, the measurement error is 3.4% and the EFSR is about 40 dB. The proposed probes have higher measurement accuracy and higher EFSR than the conventional single probe, and larger operation bandwidth than the stacked differential probes.     

Radio frequency interference suppression algorithm in the spatial domian for high-frequency radars

Radio frequency interference suppression is a very important issue in applications of high-frequency surface wave radar. This paper proposes a new interference suppression algorithm which makes use of RF interference azimuth information on the basis of learning common RF interference suppression algorithms and spatial spectrum estimation. First, we apply the MUSIC algorithm to estimate the interference azimuth and obtains the interference's signal space after the first Fourier transform; next, we use space decomposition to decompose the radar echo and obtain interference components; last, we subtract radio frequency interference components from the original signals. This algorithm can do great amount of RF interference suppression in actual data and get good results.     

Research on adaptive notch filter cascading neural network anti-jamming algorithm

Satellite navigation suffers from performance degradation in the presence of narrowband interference. We present a Global Positioning System(GPS) receiver anti-jamming algorithm based on the neural network. The method combines the adaptive notch filter with the Back Propagation(BP) neural network. We first use the two order lattice infinite impulse response adaptive notch filter to eliminate-out-of-band jamming, then use the BP neural network predictor to estimate and cancel jamming. We analyze three aspects of algorithm performance which include acquired satellite numbers,signal-to-noise improvements and iteration numbers. Simulation results show that the method can effectively suppress narrowband interference and has a better anti-jamming capacity and a faster convergence speed.     

保障个体性能的半盲干扰对齐功率分配方法

针对盲干扰对齐机制平均功率分配导致功率利用率低的问题,提出了一种半盲干扰对齐功率分配算法.在功率受限场景下,该算法能够提高整体性能,同时保障个体性能.首先,分析了功率分配对盲干扰对齐性能的影响;其次,建立了功率受限的盲干扰对齐模型,提出了最大化传输速率同时保护用户个体性能的功率分配目标;最后,为满足目标函数的约束,提出基于回溯梯度下降的功率分配算法.仿真结果表明,相比于平均功率分配,所提算法可以将系统性提高约53％.     

普光气田邻井干扰压降研究

根据普光气田现场资料,分析普光气田关井压降恢复时间和稳定生产时间的关系。建立邻井干扰计算模型,评价邻井干扰压降值及邻井干扰,并对邻井干扰规律进行敏感性分析。     

CPTED理论对城市公园设计策略的启示

城市犯罪影响着城市公园的使用,为了设计更安全宜人的城市公园,分析影响公园安全的基本要素,建立基于CPTED理论的公园设计框架,提出环境行为干涉和多方参与协同设计两大策略,并对专类活动空间、照明、标识系统等专项设计进行相关阐述。     

异构网络中几乎空白子帧存在时干扰协调方法

针对异构网络中几乎空白子帧存在时用户接入选择和资源分配方法过于复杂的情况,以及吞吐量需求难以得到满足问题,以最大化系统总吞吐量为目标提出一种易于实现的蚁群算法.在考虑不同用户不同需求的前提下,根据微基站用户在几乎空白子帧和正常子帧时受到干扰的不同,把一个微基站划分为两个虚拟基站,将所存在的问题建模为广义分配问题进行求解,同时解决了用户接入选择和资源分配问题.仿真结果表明,所提出方法与参考文献方法及两种增强型小区干扰协调固定配置结果相比,可以有效提高系统总吞吐量,同时兼顾小区边缘用户吞吐量,实现了良好的综合性能,能够更好地满足用户需求并在实际系统中易于实现.     

解相关变阶仿射投影窄带干扰抑制算法

针对仿射投影算法用于直扩系统窄带干扰抑制收敛速度慢,计算复杂度高的问题,提出了一种解相关变阶仿射投影窄带干扰抑制算法。通过对窄带干扰带来的接收信号强相关性的消除,利用接收信号正交向量优化步长,并采用结合信号特征得到的算法阶数选择机制,提高了收敛速度,降低了计算复杂度。仿真结果表明,该算法降低了归一化均方误差,明显优于变步长仿射投影窄带干扰抑制算法。     

微波暗室中基于开关切换的动态干扰仿真方法

为了准确实时复现航空通信系统数据链路中复杂电磁空间环境,本文进行了动态干扰仿真．在静态暗室中设计一种能模拟真实飞行过程抗干扰的半实物仿真系统,并分析了航空通信系统数据链路的特性.在微波暗室中复现动态干扰时,通过微波仪表的控制实现电磁空间环境动态干扰的映射构建．采用参数化模型表征技术实时建立相应的动态干扰模型,并利用最小均方值方法设计出与其匹配的干扰切换的输出算法,利用动静结合的方法仿真实现了微波暗室中通过静态喇叭模拟动态干扰模拟功能.验证结果表明,采用本文的方法能够逼真的反映飞行器在真实环境下所受动态干扰的影响,该仿真系统的研究对提高航空通信系统数据链路的抗干扰性能具有参考意义．