小波去噪和混沌理论应用于输电线缺陷检测

为了解决在利用电磁超声检测高压输电线路缺陷时，回波信号微弱且易被强大的电磁噪声覆盖而难以提取的问题。认真研究了Duffing方程和小波理论。将小波去噪技术和混沌理论结合起来，设计了一种新型微弱信号检测系统。利用MATLAB/Simulink对系统进行了仿真。实验结果证明，此系统能有效检测强电磁背景下的超声信号，进一步降低了系统的输出信噪比，提高了检测性能。

Wavelet de-noising and chaos theory applied in transmission line defect detecting

To solve the problem of echo signal which is very weak,the Duffing equation and the theory of wavelet are studied.The signal will be annihilated by strong electromagnetic noises when detecting defects in high voltage transmission lines using Electro-Magnetic Acoustic Transduce（rEMAT）.A new chaos weak signal detecting system which is combined with the technology of wavelet denoising is designed.MATLAB/Simulink is used to simulate the new detecting system.The experimental result shows that the system can detect the useful ultrasound signal under the background of strong electromagnetic noise more effectively,and it can cut down the detecting signal-to-noise ratio of system further.The detecting capability of new system is improved.