量子电压标定的叠加型噪声温度计研究

针对传统开关切换型噪声温度计存在测量时间长且需要匹配传输线的问题,搭建了一种量子电压标定的叠加型噪声温度计,从而消除切换开关。该方案一方面不需要匹配传输线,另一方面允许增加传感器电阻阻值从而提高测量的信噪比。系统主要包括量子电压赝噪声源、低噪声放大滤波电路和高精度数据采集电路等模块。采用四阶拟合外推到直流以消除传输线效应的影响,从而得到正确的热力学温度值。恒温实验室的验证性实验表明,经过100 s测量得到的结果与名义温度值的相对偏差为0.027%、不确定度为0.16%,说明了所提出方案的可行性。

Research on Quantum-voltage-calibrated Superposition Thermometry

The conventional Johnson noise thermometer with switchs is time-consuming and requires carefully matching of the transmission lines. A quantum-voltage-calibrated superposition thermometer to eliminate the switchs was proposed. In this configuration, matching the transmission lines is not necessary and the sense resistor can be increased to improve the signal to noise ratio. The system included a quantum voltage noise source, low-noise and low-distortion amplifiers, low-pass filters, and high performance analog to digital converters. A fourth-order fitting to eliminate the transmission line effects was used to obtain the thermodynamic temperature. Confirmatory experiments in thermostatic laboratories showed that the relative deviation between the measured temperature value and the nominal temperature value is 0.027% and the uncertainty is 0.16%, which demonstrated the feasibility of the proposed method.