Abstract: Through analyzing the demands of the timescale stability for small and medium-size time laboratory, it is researched that the relationship between different allocation of clock set and stability of time scale with the data of atomic clock 5071A, which is mainly used atomic clock for time keeping at present, released by the Bureau International des Poids et Mesures. Weight is one of the keys to atomic timescale algorithm. Based on the statistical analysis of the timescale calculation results obtained by different quantity clocks and different weights, a principle of determining clock weight which is suitable for the small and medium-sized time laboratories is put forward.

Key words: Timekeeping clock allocation, Atomic clocks, Frequency stability