True differential stimulus gives additional insight into nonlinear device behavior

Known n-port VNA calibration procedures in conjunction with consistent wave normalization and power calibration provide a and b waves at the calibration plane with correct absolute amplitude and relative phases. VNAs with two sources that are adjustable in amplitude and relative phase can be used for the generation of true error-corrected differential and common-mode stimulus signals. A special correction procedure has been developed that takes source crosstalk via the DUT into account. Applying these stimulating signals, single-ended or mixed-mode n-port-S-parameters can be determined.