在圆度测量中,测量点数与测量精度的关系是值得注意的问题。国标中未对圆度测量的点数作出规定,而在实际测量中,人们往往根据所要分析的圆度误差的谐波级次来选择测量点数,其依据是根据采样定理,选取大于最高谐波级次二倍的点数作为测量点数。需要指出的是这种选择是不够恰当的。因为采样定理是以频域分析为基础的,它通过求出各谐波谱项的幅值和相位来恢复原有真实波形。但在大多数圆度及回转精度的评价中,并没有计算各谱 In the roundness measurement, the relationship between the number of points and the measurement accuracy is a notable problem. However, in the actual measurement, people often choose the measurement points according to the harmonic order of the circularity error to be analyzed, and the basis is that according to the sampling theorem, more than the highest harmonic order Times double the number of points as the measurement points. It needs to be pointed out that this choice is not appropriate. Because the sampling theorem is based on frequency domain analysis, it restores the original real waveform by finding the amplitude and phase of each harmonic spectrum term. However, in most roundness and rotation accuracy evaluation, each spectrum is not calculated