基于信道特性的时反抑噪算法

Time reversal noise suppression algorithm based on channel characteristic

在信号的超声波检测过程中,检测信号在转播过程中会混入噪声,以及超声波在传播过程中存在多径效应,会造成信号的失真,导致信号的信噪比降低,为了进一步的提高超声信号处理的时反抑噪性能,利用信道的特性,即频率选择特性,对时反算法抑噪算法进行改进,提出了基于信道特性的时间反转抑噪算法.由于多径信道的基本原理,使多径信道带有一定程度的频率选择特性,这个性质能够使含有缺陷的最终聚焦信号和不含缺陷的最终的聚焦信号进行数值运算,经过数值运算后的信号中,有用信号得到了进一步的增强,抑制了多径效应,使得检测系统的信噪比增益获得进一步的提高.此算具有可行性,具有更好的信号处理效果.

In the process of ultrasonic signal detection, the detection signal will be mixedwith noise during the broadcast process, and there will be a multipath effect during the prop- agation process of the ultrasonic wave, which will cause the distortion of the signal and lead to a decrease in the signal to noise ratio of the signal. In order to improve the anti - noise performance of ultrasonic signal processing, the characteristic of the channel is used to fur- ther improve the noise suppression pefformnce of the time - reversal algorithm. This paper proposed a time reversal anti - noise algorithm based on channel characteristics. Since the multipath channel has a certain degree of frequency selection characteristics due to its basic principle, this property enabled the numerical calculation of the final focused signal contai- ning the defect and the final focused signal without the defect, and the processed signal. The useful signal was further enhanced, the multipath effect was suppressed, and the signal to noise ratio gain of the detection system was further improved.