【摘要】 分析了用于测量金属板表面波纹度的3种滤波器(JIS B 0610采用的2RC滤波器、SEP1941采用的指数滤波器和ASME B46.1采用的高斯滤波器)的传输特性,比较了原始轮廓与不同滤波器得到的波纹度轮廓的频谱特性,并指出了不同滤波器得到的波纹度参数的差异。结果表明,3种滤波器的幅值没有振荡现象,但是幅值衰减速度有显著差异。在截止波长位置,高斯滤波器和指数滤波器的幅值衰减了50%,而2RC滤波器的幅值只衰减了25%。从相位特性看,高斯滤波器和指数滤波器均属于无相位移动滤波器,而2RC滤波器属于有相位移动的滤波器,在截止波长位置的相位移动约为1.05。对比发现,在相同的截止波长下,指数滤波器与高斯滤波器的传输特性完全一致。采用2RC滤波器得到的波纹度参数W_a比采用高斯滤波器得到的W_a约大0.1μm。3种滤波器都无法同时完全抑制截止波长范围以外的成分而完全保留截止波长范围之内的成分。更多还原

【Abstract】 Transmission characteristics of three different filters including 2RC filter,Gaussian filter and an exponential filter for measuring waviness parameters on metallic sheet surface were analyzed.Then,spectrums of waviness profiles calculated by different filters and that of primary profile were compared.Finally,waviness parameters on sheet surface through different filters were figured out.Although no amplitude oscillation exist for all of the three filters,differences among amplitude attenuation rate were noticed.At the cut-off wavelength,amplitude of the Gaussian filter and the exponential filter decrease a half and that of the 2RC decreases a quarter.For phase characteristic,the Gaussian filter and the exponential filter belong to phase correct filters and the 2RC filter belong to no phase correct filter whose phase shift about 1.05 at the cut-off wavelength.Furthermore,it could be found that the transmission characteristics of the Gaussian filter are exactly same as that of the exponential filter.Moreover,the waviness parameter measured by the 2RC filter is bigger 0.1μm than that measured by the Gaussian filter.Results show that all the three filters could not exacdy suppress component beyond scope defined by cut-off wavelengths and remain component between the scope.更多还原