宽带取样示波器时基漂移的不确定度研究

Study on uncertainty of time-base drift for broadband sampling oscilloscope

时基漂移作为示波器时基误差的主要来源之一,对测量波形有着显著影响。在对示波器不确定度的评定时,对时基漂移引入的不确定度的研究也是十分必要的。首先分析了校准宽带取样示波器过程中的时基漂移现象,并进一步研究了其引入的标准不确定度分量以及去除时基漂移算法的不确定度传递算法;根据不确定度评定指南,综合时基失真、时基抖动、重复性引入的不确定度分量;最终利用本文研究的方法对Agilent86100C的取样模块86118A的带宽不确定度进行了完整的评定。结果表明时基漂移引入的不确定度为0.021 GHz,在未考虑时基漂移及其不确定度传递算法时的合成不确定为0.047 GHz,考虑时基漂移及其不确定度传递算法后的合成不确定度为0.052 GHz,因此评定因素更加多元,不确定度评定结果更加科学合理。

Time-base drift is one of the main sources of oscilloscope time-base error and has a significant impact on the measured waveform. In the evaluation of the uncertainty of the oscilloscope,it is necessary to study the uncertainty introduced by the time-base drift. Firstly,the time-base drift phenomenon in the calibration of broadband sampling oscilloscope is analyzed and by which the standard uncertainty component is introduced,and the uncertainty transfer algorithm with removal time-base drift algorithm is further studied.According to the Guide to the Uncertainty in Measurement,combined with the uncertainty component introduced by the time-base distortion,time-base jitter and repeatability,the method proposed in this paper is finallyused to evaluate the bandwidth uncertainty of the86118 A sampling module of Agilent86100 C. The results show that the uncertainty introduced by the time-base drift is 0. 021 GHz,the synthesis uncertainty,when the time-base drift and its uncertainty transfer algorithm are not considered,is 0. 047 GHz. The synthetic uncertainty after considering the time-base drift and its uncertainty transfer algorithm is 0. 052 GHz. Therefore,the evaluation factors are not only more diverse,but also the result of the uncertainty evaluationis more scientific and reasonable.