超声检测系统中消除电磁干扰的电路设计

Design of Circuit EMI Interfere Eliminated in Ultrasonic Testing System

电磁干扰是超声检测系统中的主要干扰信号,针对检测系统中消除共模噪声设计了硬件抑制措施,电路设计采用宽带差动放大器AD830进行共模噪声的抑制和前置放大,提高了电路对噪声的抑制能力。系统完成后对标样进行检测实验,通过特征扫描对薄铝工件焊缝进行质量诊断,取得了良好的效果。

In the ultrasonic testing system, EMI interference is the important interfere signal. This paper analyzed the feature of source, switching circuit which controlled N-channel FET of high-voltage shutoff emits EMI noise source from common-mode noise, and noise of EMI creating by motor. For eliminating common-mode noise, the hardware inhibition measure was designed to improve the circuit noise suppression capabilities in the testing system. After the circuit system completed, the normal samples were tested by experiment, and through the scanning of thin aluminum weld the quality of the workpiece was analyzed, and it has good results.