An additive phase noise measurement technique for mixers with non-DC IF in large signal

Mixer phase noise with respect to system level performance is often assumed negligible, measured using small signal Y-factor noise figure measurements or in some cases measuring noise direct at DC. AC coupled IF port mixers, such as triple balanced mixers, cannot be measured directly at DC and Y factor methods do not show phase noise contributions in large signal or the effect of flicker noise. A method is demonstrated in this paper that allows for direct large signal additive phase noise measurements at arbitrary (non-DC) IF frequencies and compares phase noise measurement results to the more common DC coupled measurement in the case of the double balanced mixer.