Improved Uncertainty for the Noise Source based on the Adapter Removal Methods

Noise is the fundamental to our understanding communication. For the last ten years and with the emerging of the wireless communication industry, the demand of making high accurate noise generator measurements has increased dramatically. The increased accuracy specification of the Noise Figure Analyzers is based in part on better calibrations of the Noise Source. Our primary noise source standards were calibrated by NIST in APC-7, X-band, P-band, K-band, R-band, and Q-band. Calibrated adapters are used on the NIST calibrated noise sources to characterize the system for the connector option of the noise source being used. The uncertainty of these adapter calibrations degrades the reported uncertainty. The old method would measure pairs of adapters (P-band to Type-N male & Type-N female to P-band) and split the loss of the pair as a best guess of each adapter loss. An increase in the uncertainty budget was made. The new method will require the testing of 3 different adapters. Each adapter is paired back-to-back with the two others and a measurement is made. This results in 3 measurements, 3 equations, and 3 unknowns, which can be solved for each adapter's transmission loss. No assumption about loss split is make.