In the paper some interpretation subtleties of a clock indication and clocks’ comparison are discussed. The same amount of accumulated phase is common to a “second” of different clocks. As we can measure short and long time intervals with the same (or very similar) absolute uncertainty and use a reproducible phenomenon having very short duration in comparison to the length of the interval measured therefore properly designing the measurement we can get very small uncertainty of interval’s measurement. It is explained why making the repetition series of the phenomenon longer improves the quality of averaging. Substitution of the difference of times of two clocks in the same instant and the time interval between two instants marked by each clock with the same date is justified.
XIII IMEKO TC4 International Symposium on Measurements for Research and Industrial Applications (together with IXth International Workshop on ADC Modeling and Testing, IWADC)
