激光测振仪直流增益和直流偏移的测量不确定度

The Uncertainty Evaluation of DC Gain and Offset of Laser Doppler Velocimeters

介绍了用最小二乘法评价外差式激光测振仪信号处理电路直流增益和直流偏移指标时,测量结果的不确定度分析和评定过程。讨论了影响直流增益测量不确定度的几个主要误差来源,包括信号源误差、被校仪器响应误差、被校仪器直流增益、标准仪器测量误差的影响等等。给出了减小直流增益测量不确定度的主要措施:①环境控制措施,以减少环境带来的不确定度;②选取高精度信号,以减少信号源误差带来的不确定度;③选取高精度标准测量仪器,以减少测量误差带来的不确定度。通过一个实例,给出了激光测振仪信号处理电路直流增益和直流偏移指标不确定度分析和评定结果。该过程及结论可应用在相应参数的计量校准中。

In this paper, it is described that the uncertainty of evaluation results of both DC gain and offset of the signal processing circuits of laser doppler velocimeters （LDV）, which is by using the least mean square method. It is including the courses of analysis and evaluation of uncertainty of it. Some error sources of DC gain and offset evaluation are discussed, including the errors of signal source, the measurement errors and the linearity of device under test, the influence of quantization error of linear system, the environment influence and the others. Several main methods of decreasing the evaluation errors and evaluation uncertainty have been proposed. They are environment influence controlling, in order to decrease the signal uncertainty of source. In an example of experiment, the analysis and uncertainty evaluation results of both DC gain and offset of LDV by using the method in this paper is presented. The courses and conclusion of analysis and uncertainty evaluation of both DC gain and offset in this paper, can be applied to the uncertainty evaluation of measurement standards of both DC gain and offset, can also be used in the uncertainty evaluation of DC gain and offset themselves.