过采样技术在扭矩扳子检定仪中的研究

过采样技术能够有效减小模数转换过程的噪声功率,从而提高模数转换器的分辨率。基于奈奎斯特采样定理,对模数转换器的采样频率和量化误差进行分析。通过理论分析得出,每增加一位分辨率需要增加4倍采样频率,并提出了3个影响过采样技术有效性的因素。通过在扭矩扳子检定仪中的应用过采样技术,使扭矩扳子检定仪的模数转换器提高了4位分辨率。在此基础上,对过采样技术进行了改进,使扭矩扳子检定仪的精度提高到0.3%以上。

Research of over-sampling method in torque wrench calibrating apparatus

Over-sampling can reduce the noise power during AD conversion effectively, so as to improve the resolution of ADC. The relationship between the sampling frequency of ADC and quantization error is analyzed based on the Nyquist sampling theorem. It is analyzed theoretically that increasing each resolution needs 4 times of sampling frequency, and the three factors affecting the effectiveness of over-sampling are put forward. The ADC of torque wrench calibrating apparatus is raised 4 -bit resolution by the application of over-sampling technique. Further more, we improve over-sampling technique to increase the accuracy of the torque wrench calibrating apparatus to more than 0.3%.