非均匀采样系统时基失真的一种新评价方法

Novel evaluation method of time base distortion of nonuniformly sampling data acquisition systems

提出了在多A/D合成采样系统这种非均匀采样系统中,使用时基微分非线性和时基积分非线性概念评价采样时基失真的新方法.使用正弦波激励系统,将各个子A/D的数据分别抽取形成子抽样序列,用最小二乘正弦波曲线拟合法,获得各个子抽样序列初始相位差,该相位差对应的时间差,即是各个子A/D间的采样延迟时间,它们的一致性,即是系统的采样均匀性,体现了时基失真特性,用时基微分非线性和时基积分非线性描述.在一组仿真数据上进行的实验验证了方法的正确性.在数字存储示波器的实测数据上进行的实验验证了方法的可行性.方法可以用来评价非均匀采样系统的采样时基失真.

By using both the time base differential non-linearity and integral non-linearity,a novel method to evaluate the time base distortion is presented,which deal with the nonuniformly sampling data acquisition systems.By using sinusoidal stimulating,and then re-sampling the data to create sub-series of each sub-A/D converter,through curve-fit results of sub-series sinusoidal waveforms,the phase difference between two sub-series was obtained.The time difference corresponding the phase difference is the sampling time delay between two sub-A/D.Their consistency is the time base distortion of nonuniformly sampling systems,which can be expressed in time base difference non-linearity and time base integral non-linearity.In simulation test,the correctness of the method was validated.In practical experiment on a digital storage oscilloscope,the feasibility of the method was proved.The method above can be use to evaluate the time base distortion of nonuniformly sampling data acquisition systems.