应用DC/DC变换器作为激励源时,其采用的不同类型及加工工艺的电源电缆,对产品辐射发射水平会产生不同的影响。对电源电缆的不同类型、屏蔽层搭接方式、连接器、安装位置等因素对电磁辐射发射的影响进行了比对实验。实验结果表明,采用屏...应用DC/DC变换器作为激励源时,其采用的不同类型及加工工艺的电源电缆,对产品辐射发射水平会产生不同的影响。对电源电缆的不同类型、屏蔽层搭接方式、连接器、安装位置等因素对电磁辐射发射的影响进行了比对实验。实验结果表明,采用屏蔽电线且屏蔽层和连接器间实现360°环形接地搭接时,相对普通非屏蔽电缆可提供约30 d B的屏蔽度。展开更多
给出 MIL-STD-461F 中拉杆天线试验布置的变化,然后选取有代表性的4个样品进行试验来分析拉杆天线试验布置的变化对测量结果的影响。测量结果表明,在大约5 MHz 以上频段的多个频点,依据 F 版的测量布置得到的测量结果明显小于依据 D 版...给出 MIL-STD-461F 中拉杆天线试验布置的变化,然后选取有代表性的4个样品进行试验来分析拉杆天线试验布置的变化对测量结果的影响。测量结果表明,在大约5 MHz 以上频段的多个频点,依据 F 版的测量布置得到的测量结果明显小于依据 D 版和 E 版的测量布置得到的结果。而对于5MHz 以下的频段,在某些频点上,依据 F 版的测量布置得到的测量结果明显大于依据 D 版和 E 版的测量布置得到的结果。展开更多
Academy of Sciences,Beijing 100029 2 Lanzhou University,Lanzhou 730000 3 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences,Lanzhou 730000 4 Nanjing University of Infor...Academy of Sciences,Beijing 100029 2 Lanzhou University,Lanzhou 730000 3 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences,Lanzhou 730000 4 Nanjing University of Information Science＆Technology,Nanjing 210044 Using both fast and slow electric field change sensors and field mill,multi-station observations on lightning flashes over China inland plateau areas were conducted during the summer of 2004.All of the stations were synchronized by GPS with a time-resolution of±50 ns.Using the different time of arrival（DTOA）and based on the fast electric field change sensor,a lightning radiation location technique was developed.Radiation pulses in the initial stages of five intracloud（IC）lightning discharges which occurred on 20 August were analyzed.The results indicate that the technique developed could effectively locate the lightning radiation sources.Furthermore,the lightning discharges were compared with the Doppler radar data.The results show that the radiation sources were well associated with the storm development.When the storm was at the mature stage with an echo top of about 10.9 km,the radiation sources ranged from 5.2 to 8.3 km above mean sea level;when the storm gradually became weaker,with echo top of about 7.9 km,the radiation sources ranged from 3.0 to 5.9 km.In particular,one of the IC lightning discharges ranged from 3.0 to 4.9 km during the dissipation stage of the storm.The results also indicate that the radiation sources were closely associated with the high reflectivity region（25–50 dBZ）of the storm,which,to some extent,demonstrates the reliability of the location results,thereby showing that multi-station observations of fast electric field change sensors could be a useful tool for monitoring the storm development.Location errors from radiation sources were also compared with the radar data and the results of a simple simulation.It was found that the errors were getting smaller when the radiation sources approached the center of the de展开更多
文摘应用DC/DC变换器作为激励源时,其采用的不同类型及加工工艺的电源电缆,对产品辐射发射水平会产生不同的影响。对电源电缆的不同类型、屏蔽层搭接方式、连接器、安装位置等因素对电磁辐射发射的影响进行了比对实验。实验结果表明,采用屏蔽电线且屏蔽层和连接器间实现360°环形接地搭接时,相对普通非屏蔽电缆可提供约30 d B的屏蔽度。
文摘给出 MIL-STD-461F 中拉杆天线试验布置的变化,然后选取有代表性的4个样品进行试验来分析拉杆天线试验布置的变化对测量结果的影响。测量结果表明,在大约5 MHz 以上频段的多个频点,依据 F 版的测量布置得到的测量结果明显小于依据 D 版和 E 版的测量布置得到的结果。而对于5MHz 以下的频段,在某些频点上,依据 F 版的测量布置得到的测量结果明显大于依据 D 版和 E 版的测量布置得到的结果。
基金the 100 Talents Program of the Chinese Academy of Sciencesthe Special Research Project for Public Welfare of China under Grant No.200704027-1the National Natural Science Foundation of China under Grant No.40930949
文摘Academy of Sciences,Beijing 100029 2 Lanzhou University,Lanzhou 730000 3 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences,Lanzhou 730000 4 Nanjing University of Information Science＆Technology,Nanjing 210044 Using both fast and slow electric field change sensors and field mill,multi-station observations on lightning flashes over China inland plateau areas were conducted during the summer of 2004.All of the stations were synchronized by GPS with a time-resolution of±50 ns.Using the different time of arrival（DTOA）and based on the fast electric field change sensor,a lightning radiation location technique was developed.Radiation pulses in the initial stages of five intracloud（IC）lightning discharges which occurred on 20 August were analyzed.The results indicate that the technique developed could effectively locate the lightning radiation sources.Furthermore,the lightning discharges were compared with the Doppler radar data.The results show that the radiation sources were well associated with the storm development.When the storm was at the mature stage with an echo top of about 10.9 km,the radiation sources ranged from 5.2 to 8.3 km above mean sea level;when the storm gradually became weaker,with echo top of about 7.9 km,the radiation sources ranged from 3.0 to 5.9 km.In particular,one of the IC lightning discharges ranged from 3.0 to 4.9 km during the dissipation stage of the storm.The results also indicate that the radiation sources were closely associated with the high reflectivity region（25–50 dBZ）of the storm,which,to some extent,demonstrates the reliability of the location results,thereby showing that multi-station observations of fast electric field change sensors could be a useful tool for monitoring the storm development.Location errors from radiation sources were also compared with the radar data and the results of a simple simulation.It was found that the errors were getting smaller when the radiation sources approached the center of the de
