中低频段 meaning in Chinese

lmf=low frequency
lmf=low-mid frequency
lmf=lowfrequency

- 2 . in order to accomplish the extraction measuremellt of distorted wavefront on specific plane of a laser beam , a crsi ( cyc1ic radial shearing interferometer ) based on relay imaging technique was built . the experiinental result on this crsi shows it can used to test the spatial mid and low frequency wavefront distortion
二、为了实现激光光束在确定平面上的波前畸变的准确检测，采用中继成像技术建立了一套基于空间相位调制的环路径向剪切干涉波前传感硬件系统，实验证明，它可用于中低频段波前畸变的检测。
It shows that a disadvantag ekists when a crsi is used to measure a step structure in a wavefront , but it is useful to adjust a crsi system with lcslm . 4 . according to the didriction effect of an aperture , the spatial resolution of our crsi was analyzed and the transform function of our crsi was calibrated by using the psd method of a step wavefront . and some factors which are associated with the accuracy of our crsi were analyzed too
四、从光学系统衍射效应的角度分析了本文建立的环路径向剪切干涉仪的空间分辨率，并利用波前功率谱密度的概念对该干涉仪的空间频率响应特性进行了标定，分析了限制该干涉仪测量精度的主要因素以及径向剪切比与测量精度的关系，并指出了该干涉仪的测量范围，结果显示该干涉仪基本上可用于准确测量中低频段的波前畸变。