Superposition Johnson Noise Thermometer with a Fully Differential Structure
- Resource Type
- Conference
- Authors
- Han, Qina; Zhou, Kunli; Shi, Yang; Yang, Jian; Liang, Qiming; Qu, Jifeng
- Source
- 2022 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) Instrumentation and Measurement Technology Conference (I2MTC), 2022 IEEE International. :1-6 May, 2022
- Subject
- Bioengineering
Engineering Profession
General Topics for Engineers
Signal Processing and Analysis
Temperature measurement
Thermometers
Uncertainty
Electromagnetic interference
Measurement uncertainty
Preamplifiers
Time measurement
Johnson noise
thermodynamic temperature
superposition
differential
resistance measurement
- Language
- ISSN
- 2642-2077
This paper proposes a fully differential superposition Johnson noise thermometer to improve the robustness of the system to electromagnetic interference (EMI). The single-ended reference noise source and/or single-ended preamplifiers in previous works are replaced with a differential reference signal source and differential preamplifiers, respectively, leading to a significant improvement of the common-mode rejection of EMI. The new structure provides a much cleaner spectrum which is of importance to practical industrial applications. We also develop a resistance measurement unit (RMU) to reduce the system cost. The RMU has an accuracy of < 2×10 -5 in its full operating range from 600 Ω to 2.5 kΩ. Measurement of the melting point of gallium with an integration time of 50 seconds gives a result of 302.93 K with a statistical uncertainty of 0.18 K. The experiments demonstrated the feasibility of the proposed differential structure.