现有脉内复合调制波形存在调制方式简单、自相关旁瓣电平高的不足,致使发射波形在应用中易被截获且对弱目标检测性能较差。针对上述问题,在线性调频(linear frequency modulation,LFM)-Costas雷达波形中引入二相编码(binary phase shift...现有脉内复合调制波形存在调制方式简单、自相关旁瓣电平高的不足,致使发射波形在应用中易被截获且对弱目标检测性能较差。针对上述问题,在线性调频(linear frequency modulation,LFM)-Costas雷达波形中引入二相编码(binary phase shift keying,BPSK),设计了LFM-Costas-BPSK波形。一方面,降低了子脉冲间的相关性从而有效抑制了自相关旁瓣电平;另一方面,提高了波形复杂度,因而降低了被截获概率。仿真实验分析了关键参数对波形性能的影响,验证了所设计的LFM-Costas-BPSK波形的有效性。展开更多
该文在步进频信号的基础上,把基于混沌调制的多载波相位编码(Multi-Carrier Phase Coded,MCPC)信号作为子脉冲,用Costas跳频代替频率的线性步进,设计出脉间Costas跳频脉内多载波混沌相位编码(Inter-Pulse Costas frequency hopping and ...该文在步进频信号的基础上,把基于混沌调制的多载波相位编码(Multi-Carrier Phase Coded,MCPC)信号作为子脉冲,用Costas跳频代替频率的线性步进,设计出脉间Costas跳频脉内多载波混沌相位编码(Inter-Pulse Costas frequency hopping and intra-pulse Multi-Carrier Chaotic Phase Coded,IPC-MCCPC)雷达信号,并对其模糊函数及自相关性能进行了研究。仿真分析表明,该文设计的信号继承了步进频信号用较小的瞬时带宽合成较大的工作带宽的优点,同时有效克服了步进频信号存在的距离-速度耦合的缺点。脉内多载波特性使得这种信号在保持总带宽和步进频信号相等的条件下减少跳频阶数,从而提高信号处理的数据率;混沌调相的引入使得这种信号具有更强的保密性;脉间频率的随机跳变使其模糊函数具有更低的周期性旁瓣。这种信号众多的参数、灵活的结构及较大的调制复杂度,增加了侦察接收机匹配和识别的难度,从而提高雷达的反截获性能。展开更多
Two long carbon chain alkyl (aqua) Costa type organocobalt complexes (R=C 6H 13 and C 8H 17 ) have been synthesized for the first time and characterized by elemental analysis, UV Vis and 1H NMR. Their inclusion behavi...Two long carbon chain alkyl (aqua) Costa type organocobalt complexes (R=C 6H 13 and C 8H 17 ) have been synthesized for the first time and characterized by elemental analysis, UV Vis and 1H NMR. Their inclusion behavior with β cyclodextrin was studied by 1H NMR methods. It was indicated that in aqueous solution supramolecular adducts have been formed, in which the alkyl groups of the vips were included into the cavity of β CD. Cyclic voltammetry methods was also used to study the electrochemical properties of organocobalt complexes in the absence and presence of β CD. [WT5HZ]展开更多
文摘Two long carbon chain alkyl (aqua) Costa type organocobalt complexes (R=C 6H 13 and C 8H 17 ) have been synthesized for the first time and characterized by elemental analysis, UV Vis and 1H NMR. Their inclusion behavior with β cyclodextrin was studied by 1H NMR methods. It was indicated that in aqueous solution supramolecular adducts have been formed, in which the alkyl groups of the vips were included into the cavity of β CD. Cyclic voltammetry methods was also used to study the electrochemical properties of organocobalt complexes in the absence and presence of β CD. [WT5HZ]
