摘要
介绍了DVD视盘机电磁辐射产生的机理和原因,通过测试数据的比较分析对辐射源及耦合路径进行定位,并利用改变解码PCB板的接地方式、改善不同模块间互连线缆的空间分布位置、使用磁珠及电容对时钟/电源走线进行滤波处理、强化机器外壳的屏蔽效能等方法对辐射进行抑制。改进后的产品经测试符合FCC Part15 Class B的要求,并有6dB以上的裕量。
The mechanism and reasons of electromagnetic radiation caused by DVD player are mainly introduced. By comparing and analyzing of measurement data, the locations of radiation sources and coupling paths are found out. Variety of countermeasure methods are utilized to suppress EMI emission, such as changing the grounding distribution on decoding PCB, improving the spatial distributions of interconnected cable between different modules, using beads and capacitors as filters on clock traces and power supply traces, strengthening shielding efficiency of cabinet and so on. The testing result accords with the requirements of FCC Part15 Class B standard completely after improving, and the margin is more than 6 dB from limit.
关键词
DVD视盘机
辐射骚扰场强
接地
滤波
屏蔽
耦合
DVD player
radiation disturbance field strength
grounding
filter
shield
coupling
