Evaluation of measurement uncertainty based on time-base error compensation of bandwidth sampling oscilloscope

摘要

Time-base error is a key factor affecting the accuracy of time-domain measurement of bandwidth sampling oscilloscopes. Therefore, it is necessary to compensate the time-base error of measurement results, and it is also very important to evaluate the uncertainty of time-base error compensation of measurement results. In this paper, the estimation and compensation algorithm of time-base error is analyzed firstly. Then the model of calculating the uncertainty of every point of the measurement waveform which have compensated the time-base error is constructed based on the covariance matrix. Finally, the uncertainty of each point of the high-speed pulse signal after time-base error compensation is calculated, and the maximum voltage value of the uncertainty components of every point of the measurement waveform is about 2. 3mV. The maximum voltage value is calculated as the uncertainty of the rise time of the measured signal, which is about 0. 24ps. The result indicating that the method of evaluation the uncertainty of the measurement waveform by the point-by-point is feasible and reasonable.