Noise Thermometry - Page 13
The main problem is that the signal levels involved are
extremely small, approaching the limits of measurement.
Prior art Johnson Noise Thermometers use 100 ohm sense
resistance and 100 kilo hertz bandwidth.
At 20°C, the noise signal = 1.27 micro volts RMS.
Measuring to ¬plus or minus 0.3 K means measuring
this noise to ¬plus or minus 1.27 nano volts, which
is at the limits of measurement.
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