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US 3,937,086 AGranted
Noise thermometer
AssigneeArthur D. Little, Inc.
InventorPeter C. von Thuna
Life of this patent
Estimating the term…
Abstract
A thermometer based upon the measurement of spontaneous thermal noise in the form of electrical fluctuations in a sensor resistance, in which the sensor is included within an input circuit. The input circuit is inductively coupled to a matched circuit tuned to a selected band width of the noise and which includes the measuring electronics which preferably discriminates between random amplifier noise and the sensor signal by correlation techniques.
Claims7
A thermometer which measures spontaneous thermal noise in the form of voltage fluctuations across a sensor resistor, said thermometer comprising in combination:
- an electrical circuit inductively coupled to said resistor and being tuned so that the losses in said circuit are substantially caused by said sensor resistor, the parameters of said circuit being so matched to the sensor resistor and the inductive coupling that the thermal noise power generated by said resistor is concentrated in a selected frequency band, said inductive coupling being a transformer, the primary of which is connected across said resistor, said electrical circuit including the secondary winding of said transformer and a precision capacitor connected across said secondary winding;
- and
- means connected in said electrical circuit for measuring the absolute mean square value of said voltage fluctuations.
Dependencies are inferred from the claim text.