Characterization and behavior of comb phase-standards

Measurement of two phase-standard designs based on different technologies, over a range of drive frequencies shows differences in behavior. The step-recovery based design is nonlinear with both power and frequency but the time-domain pulse response of the newer phase standard shows little variation with drive frequency. Source-match of the phase standard is a potential source of phase error and a load-pull approach is proposed to provide this correction. The measurement system is traceable to the electro-optic primary standard at NPL. Interpolation methods for comb frequency results are discussed.