Measurement and study of the jitter measurement floor of a broadband sampling oscilloscope

The jitter measurement floor of a broadband sampling oscilloscope represents an effective lower bound for time-domain jitter measurements and can limit the accuracy of low-jitter characterization. Because characterization procedures can be complex and the results are affected by multiple coupled test conditions, this paper develops a systematic time-domain framework for characterizing the jitter measurement floor. A reproducible measurement setup based on a low-jitter signal source is established, and the effects of vertical sensitivity, input frequency, and input amplitude on the jitter measurement floor are quantitatively evaluated. Based on these results, a rapid parameter-sweep and screening procedure is presented to quickly determine the parameter setting range associated with a near-minimum jitter measurement floor. To reduce reliance on ultra-low-jitter reference sources, simulations and experiments are conducted to examine the relationship among the measured jitter, the source jitter, and the jitter measurement floor of the oscilloscope; the results are consistent with a root-mean-square combination model. Leveraging this model, a root-mean-square-based method is introduced to extract the jitter measurement floor, which remains applicable when an ultra-low-jitter source is unavailable. Experimental results support the effectiveness and practical feasibility of the proposed workflow, suggesting an accessible route toward reproducible time-domain characterization of the jitter measurement floor of sampling oscilloscopes.