摘要
超声管外测压中回波信号易受到噪声的干扰,针对循环法时间测量中存在门限电压高、触发点漂移问题,提出用小波阈值去噪法对回波信号进行预处理。仿真结果表明:选用Sym8小波、"heursure"阈值准则,采用软阈值法,分解尺度为9时,去噪效果最好。去噪后,门限电压降低,消除了触发点的漂移。
Echo signal is easy disturbed by noise in ultrasonic pressure measuring outside pipe. The wavelet threshold denoising method was developed to reduce the effect of noise in consideration of the high threshold voltage and trigger point excursion in the cycled time testing. The simulation experimental results show that the echo signal is denoised best by adopting the Sym8 wavelet, the ＂heursure＂ threshold rules, the soft denoising method and 9 scales＇ decomposition. The threshold voltage is lowered and trigger point excursion is well eliminated after the signal denoised using above method.
出处
《机床与液压》
北大核心
2009年第12期157-160,共4页
Machine Tool & Hydraulics
关键词
超声测压
阈值去噪
回波信号
Ultrasonic pressurent
Threshold denoising
Echo signal
