采用窗函数法、频率抽样法和切比雪夫最佳一致逼近法，通过调用Matlab信号处理工具箱中的函数设计低通数字滤波器。
By using MATLAB signal and using window method, frequency sampling and Chebyshev approximation the design of low pass digital filter in the toolbox have been processed.
本文主要提出两种消除数字地震信号中长周期随机干扰的方法：窄带低通滤波对消法和自适应高通滤波法。
Two methods with which the long disturbance is removed from the digital are introduced: narrow band low - pass filtering canceling method and adaptive high - pass filtering method.
鉴于这种情况，我们先使用低通滤波对轮廓曲线作光顺处理，随后再采用基于面积误差的多边形逼近法对曲线作逼近处理。
And they are often distorted. First, a low passed filter is used to smooth the contour. And a polygon approximating method based on area error is used to approximate the contour.
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