Calibration of noise power transfer standards, measurement uncertainties and long term stability

Calibration of plasma noise power standards for the transfer of the unit watt for noise power against the primary thermal noise standard and calibration against a plasma source working standard are discussed. In these procedures the noise power intercomparison takes place at quite different power levels. This gives rise to different influences on the uncertainties of the calibration and to special requirements concerning the long time stability of the measuring equipment.