为系统客观地评价某通信系统的抗电磁干扰能力,提出一种以误码率为评价指标的电磁干扰效应实验方法,确定了不同干扰信号对该通信系统的作用规律,分析了干扰机理,结果表明:同频干扰时,在产生误码功率的前2 d Bm,误码率逐渐增大,而后1 d B...为系统客观地评价某通信系统的抗电磁干扰能力,提出一种以误码率为评价指标的电磁干扰效应实验方法,确定了不同干扰信号对该通信系统的作用规律,分析了干扰机理,结果表明:同频干扰时,在产生误码功率的前2 d Bm,误码率逐渐增大,而后1 d Bm范围内,误码率迅速增加到0.47,干扰功率与发射功率呈线性变化;误码率达到10-2数量级,话筒发出吱吱声,达到0.47时显示屏出现死机现象;偏离发射频率2 MHz范围内的信号易产生干扰;带外强干扰信号会使通信系统减敏,干扰功率与信号频偏呈正比;互调干扰的两路信号同步变化时,其功率与发射功率呈线性关系,反之功率与信号频率之间的关系相同;扩频或RS编码可提高通信系统对同频小信号的抑制效果,而对邻频干扰,扩频反而使系统更易受到干扰,且产生干扰的功率区间变宽。展开更多
收发组合作为无人机数据链系统的核心部件,其抗电磁干扰能力直接影响机载通信安全。为检验核电磁脉冲(HEMP)辐照条件下某型无人机数据链系统的可靠性,基于快沿电磁脉冲模拟系统建立了无人机HEMP效应试验平台,以典型"失锁"效...收发组合作为无人机数据链系统的核心部件,其抗电磁干扰能力直接影响机载通信安全。为检验核电磁脉冲(HEMP)辐照条件下某型无人机数据链系统的可靠性,基于快沿电磁脉冲模拟系统建立了无人机HEMP效应试验平台,以典型"失锁"效应作为受干扰判别依据,开展了无人机数据链系统辐照效应研究,分析了无人机数据链"失锁"效应机理。结果表明:核电磁脉冲场强达到72 k V/m时能够对飞机数据链测试系统产生干扰,导致地面监视系统回报通信链路全部失锁、飞行控制模拟器黑屏,且收发组合放置姿态改变基本不影响数据链系统干扰阈值。通过电磁仿真分析发现,飞行控制模拟器端接电缆耦合外界强场信号使收发组合供电瞬时中断,进而导致数据链测试系统产生干扰。排除数据链测试系统中飞行控制模拟器,在辐照场强<90 k V/m情况下,无人机下行遥测链路不会出现失锁。展开更多
Pure organic materials with persistent and efficient room-temperature phosphorescence have recently aroused great research interest due to their vast potential in applications.One crucial design principle for such mat...Pure organic materials with persistent and efficient room-temperature phosphorescence have recently aroused great research interest due to their vast potential in applications.One crucial design principle for such materials is to suppress as much as possible the non-radiative decay of the triplet exciton while maintaining a moderate phosphorescent radiative rate.However,molecular engineering often exhibits similar regulation trends for the two processes.Here,we propose that the quantum interference caused by aggregation can be utilized to control the phosphorescent and non-radiative decay channels.We systematically analyze various constructive and destructive transition pathways in aggregates with different molecular packing types and establish clear relationships between the luminescence characters and the signs of the singlet and triplet excitonic couplings.It is shown that the decay channels can be flexibly switched on or off by regulating the packing type and excitonic couplings.Most importantly,an enhanced phosphorescent decay and a completely suppressed non-radiative decay can be simultaneously realized in the aggregate packed with inversion symmetry.This work lays the theoretical foundation for future experimental realization of quantum interference effects in phosphorescence.展开更多
文摘为系统客观地评价某通信系统的抗电磁干扰能力,提出一种以误码率为评价指标的电磁干扰效应实验方法,确定了不同干扰信号对该通信系统的作用规律,分析了干扰机理,结果表明:同频干扰时,在产生误码功率的前2 d Bm,误码率逐渐增大,而后1 d Bm范围内,误码率迅速增加到0.47,干扰功率与发射功率呈线性变化;误码率达到10-2数量级,话筒发出吱吱声,达到0.47时显示屏出现死机现象;偏离发射频率2 MHz范围内的信号易产生干扰;带外强干扰信号会使通信系统减敏,干扰功率与信号频偏呈正比;互调干扰的两路信号同步变化时,其功率与发射功率呈线性关系,反之功率与信号频率之间的关系相同;扩频或RS编码可提高通信系统对同频小信号的抑制效果,而对邻频干扰,扩频反而使系统更易受到干扰,且产生干扰的功率区间变宽。
文摘收发组合作为无人机数据链系统的核心部件,其抗电磁干扰能力直接影响机载通信安全。为检验核电磁脉冲(HEMP)辐照条件下某型无人机数据链系统的可靠性,基于快沿电磁脉冲模拟系统建立了无人机HEMP效应试验平台,以典型"失锁"效应作为受干扰判别依据,开展了无人机数据链系统辐照效应研究,分析了无人机数据链"失锁"效应机理。结果表明:核电磁脉冲场强达到72 k V/m时能够对飞机数据链测试系统产生干扰,导致地面监视系统回报通信链路全部失锁、飞行控制模拟器黑屏,且收发组合放置姿态改变基本不影响数据链系统干扰阈值。通过电磁仿真分析发现,飞行控制模拟器端接电缆耦合外界强场信号使收发组合供电瞬时中断,进而导致数据链测试系统产生干扰。排除数据链测试系统中飞行控制模拟器,在辐照场强<90 k V/m情况下,无人机下行遥测链路不会出现失锁。
基金National Science Foundation of China,Grant/Award Numbers:22033006,21833006,22173074,22203068China Postdoctoral Science Foundation,Grant/Award Number:2021M702734。
文摘Pure organic materials with persistent and efficient room-temperature phosphorescence have recently aroused great research interest due to their vast potential in applications.One crucial design principle for such materials is to suppress as much as possible the non-radiative decay of the triplet exciton while maintaining a moderate phosphorescent radiative rate.However,molecular engineering often exhibits similar regulation trends for the two processes.Here,we propose that the quantum interference caused by aggregation can be utilized to control the phosphorescent and non-radiative decay channels.We systematically analyze various constructive and destructive transition pathways in aggregates with different molecular packing types and establish clear relationships between the luminescence characters and the signs of the singlet and triplet excitonic couplings.It is shown that the decay channels can be flexibly switched on or off by regulating the packing type and excitonic couplings.Most importantly,an enhanced phosphorescent decay and a completely suppressed non-radiative decay can be simultaneously realized in the aggregate packed with inversion symmetry.This work lays the theoretical foundation for future experimental realization of quantum interference effects in phosphorescence.
