In this paper, it is described that the
uncertainty of evaluation results of Offset of linear
measurement system by using
the least mean square four-parameter sine wave curve-fit method, including the courses of analysis and evaluation of
uncertainty. By using the method from the Chinese military standard GJB 3756-1999 "expression and evaluation of uncertainty in
measurement", some error sources of Offset evaluation are discussed, including the signal amplitude errors, the harmonic distortion of sampling serials, the quantization errors and noise and the spurious distortion, the jitter of the signal periods in sampling serials, the calculation errors of software, and the others. The uncertainty of offset of linear measurement systems is given, and several main methods about decreasing the offset evaluation errors and evaluation uncertainty are proposed. In an example of experiment, the analysis and uncertainty evaluation results of Offset by using the method in this paper are presented. The validation of the uncertainty shows the correctness and rightness of the method. The courses and conclusion of analysis and uncertainty evaluation of offset in this paper, can be applied to the uncertainty evaluation of measurement standards of Offset and the uncertainty evaluation of offset itself.