某型网络交换机辐射发射超标的分析与整改
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摘要
针对某网络交换机产品的辐射发射超标问题,论述了辐射发射超标问题的整改方法和思路。依据EMC三要素,结合SI/EMC仿真及相关仪器设备(频谱仪、示波器、近场探头),对问题进行了详细的定位分析,最终确定了P12引脚的时钟频率信号是造成产品辐射发射超标的原因。在P12电路上增加10Ω匹配电阻后,产品的辐射发射测试结果符合GB 9254-2008 Class B的标准限值要求。
The general methods and ideas for solving the problem of excessive radiation from a network switch is discussed. Based on the principle of three key elements of EMC, the procedure of locating the EMC faults in the network switch is provided. The EMC problem is analysised according to the measurement with some instruments(spectrum analyzer, oscilloscope, near-field probe) and SI/EMC simulation with EM software. Finally, the clock frequency signal of the pin P12 is determined to be the reason of the radiation exceeding the standard. After a matched resistance of 10 Ω being connected to the pin P12, the radiation of the products according to the test results meets the limitation of the GB 9254-2008 Class B.
The general methods and ideas for solving the problem of excessive radiation from a network switch is discussed. Based on the principle of three key elements of EMC, the procedure of locating the EMC faults in the network switch is provided. The EMC problem is analysised according to the measurement with some instruments(spectrum analyzer, oscilloscope, near-field probe) and SI/EMC simulation with EM software. Finally, the clock frequency signal of the pin P12 is determined to be the reason of the radiation exceeding the standard. After a matched resistance of 10 Ω being connected to the pin P12, the radiation of the products according to the test results meets the limitation of the GB 9254-2008 Class B.
引文
[1]国家质量监督检验检疫总局,国家标准化管理委员会.GB 9254-2008信息技术设备的无线电骚扰限值和测量方法[S].北京:中国标准出版社, 2008.
[2]郑军奇. EMC电磁兼容设计与测试案例分析(第2版)[M].北京:电子工业出版社, 2010.
[3]朱文立.电磁兼容设计与整改对策及案例分析[M].北京:电子工业出版社, 2012.
[4](美)Henry W.Ott.电子系统中噪声的抑制与衰减技术(第2版)[M].王培清,李迪,译.北京:电子工业出版社,2003.
[2]郑军奇. EMC电磁兼容设计与测试案例分析(第2版)[M].北京:电子工业出版社, 2010.
[3]朱文立.电磁兼容设计与整改对策及案例分析[M].北京:电子工业出版社, 2012.
[4](美)Henry W.Ott.电子系统中噪声的抑制与衰减技术(第2版)[M].王培清,李迪,译.北京:电子工业出版社,2003.