Abstract:
A system for measuring temperature has been provided wherein the absolute temperature Ts is determined by measuring the thermal noise power, i.e., the product of the thermal noise voltage and the thermal noise current generated by a sensing resistor at temperature Ts. The measured thermal noise power from the sensing resistor is a linear function of absolute temperature. The system senses the thermal noise voltage by means of a voltage-sensitive preamplifier and the thermal noise current by means of a currentsensitive preamplifier. The signals from the two preamplifiers are separately detected and stored in separate sample-and-hold circuits after which they are multiplied in a multiplier to obtain an output proportional to the thermal noise power. This means of temperature measurement is independent of the sensingresistor composition, the mass and nature of the charge carriers, and, in principle, the ohmic value of the sensing resistor.