电磁干扰信号频谱分析

在电磁兼容测试过程中,针对某些产品仅因印制板上某些脉冲信号引起辐射骚扰超标导致产品认证失败的问题,首先介绍了与傅里叶变换有关的3个不等式及证明过程,利用这些不等式对不规则脉冲信号的频谱包络进行了详细推导,并用一个具体的不规则脉冲信号进行了频谱包络验证。结果表明:工程上对一些不用精确求取不规则脉冲信号频谱的应用时,利用以上3个不等式即可大大简化频谱包络求取过程,掌握这些脉冲信号的频谱包络特征,对于优化印制板布局、布线具有十分重要的工程指导意义。

Spectrum Analysis on Electromagnetic Interference Signal

During the EMC test, aiming at the problem that some products can’t pass test owing to some pulse signals which causes excessive radiation disturbance, this paper introduces three inequalities and proof process, which are related to Fourier transform, and then takes advantage of these inequalities to attain spectral envelope of irregular pulse signal. Finally, a specific irregular pulse signal spectral envelope is applied to verify this method. The result shows that some application cases without obtaining accurate irregular pulse signal spectrum, using the above three inequalities can greatly simplify the process of calculating its spectral envelope. It’s a very useful guideline for engineers who master the frequency spectrum characteristics of these pulse signals to handle PCB layout and route.