Research of Low Noise Analog Measurement on High Temperature Thermocouple Based on dsPIC33

Since thermocouple has an intrinsic disadvantage that its signal is very weak, many problems usually appear such as large noise and low temperature resolution when thermocouples are being used. Aiming this defect on thermocouple measurement, this paper proposes a solution of analog circuit design that provides the character of low noise and high SNR. This paper discusses the analog circuit design and calculation based on the S-type thermocouple which is often used for a very wide temperature range. This designed module can be applied to measurement instruments.