If two noisy electrical dipoles are connected with an electric line, noise power can flow through the line. Such power can be measured, in the audio frequency range, with a wattmeter with spectral display capabilities. If the dipoles are two equal resistors in thermodynamic equilibrium, the power depends exclusively on the temperature difference, giving a differential noise thermometry method. If the dipoles are at the same temperature, but one is out of thermodynamic equilibrium (because of a flowing dc current), noise power depends on excess noise only, and it is possible to measure excess noise far below Johnson noise threshold
Practical realization of Nyquist's gedanken experiment / Callegaro, Luca; Pisani, Marco. - In: APPLIED PHYSICS LETTERS. - ISSN 0003-6951. - 89:3(2006), pp. 034105-1-034105-3. [10.1063/1.2222250]
Practical realization of Nyquist's gedanken experiment
CALLEGARO, LUCA;PISANI, MARCO
2006
Abstract
If two noisy electrical dipoles are connected with an electric line, noise power can flow through the line. Such power can be measured, in the audio frequency range, with a wattmeter with spectral display capabilities. If the dipoles are two equal resistors in thermodynamic equilibrium, the power depends exclusively on the temperature difference, giving a differential noise thermometry method. If the dipoles are at the same temperature, but one is out of thermodynamic equilibrium (because of a flowing dc current), noise power depends on excess noise only, and it is possible to measure excess noise far below Johnson noise thresholdI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
