【摘要】 能量天平法作为一种质量量子基准研究方案,其中磁链差测量是能量天平测量过程的核心,其基本原理是对线圈感应电压的时间积分进行测量。原有的磁链差测量方法是基于数字积分原理的,当其应用于能量天平同步测量方法中时,难以克服数据采集卡的本征弱点,无法满足10-8量级的相对标准不确定度需求。为此,基于双积分型模数转换器（ADC）提出了一种模拟积分测量原理的磁链差测量方法。该方法利用双积分型ADC的模拟积分测量特性,消除原方法中电平保持采样过程引入的测量误差;通过定序触发多个并联的ADC进行接续测量,去除ADC数字量化过程引入的测量死区;配合使用多ADC分时清零方法,抑制时变噪声累积导致的测量分散性。测试结果表明,在同步测量过程中应用上述方法之后,磁链差测量的相对标准不确定度由原来的10^-6量级抑制至1.7×10^-8。更多还原

【Abstract】 The joule balance method is a quantized definition of the unit of mass research programme,in which the flux linkage difference measurement is a core part during the measurement process of joule balance,and its basic principle is the integral measurement of coil induced voltage over time. When the original flux linkage difference measurement method based on the digital integration principle is applied to the synchronous measurement process of joule balance,it is difficult to overcome the intrinsic weakness of the data acquisition card so that it cannot achieve the10^-8 magnitude of relative standard uncertainty. Therefore,a new method based on the dual-slope integration ADC is proposed to achieve the analog integral measurement. With the continuously analog integrating measurement characteristic of the dual-slope integration based ADC,the measurement error introduced by the level holding sampling process in the original method is eliminated. The measurement dead-zone introduced by ADC digital quantization is removed by the successive triggered measurement of multiple parallel ADCs. The measurement dispersion introduced by the accumulation of time-varying noise is suppressed by the time-shared noise zeroing of multiple ADCs. The test results show that after applying the above method in the synchronous measurement process,the relative standard uncertainty of flux linkage difference measurement is suppressed from 10^-6 to 1. 7 × 10^-8.更多还原