用于守时工作的时间间隔计数法与双混频时差测量比对法的比较

A Comparison Between Time Interval Counter and Dual Mixer Time Difference System for Time Keeping

为了比较用于守时工作的时间间隔计数法和双混频时差测量法,分析了国家授时中心时频基准实验室的两种测量比对设备(SR620时间间隔计数器和PCOMP多通道相位比较仪)对同一组原子钟进行测量时所得到的结果(钟的速率、RMS、测量精度和稳定度)。分析所得的主要结论是:双混频时差测量法具有更高的比对精度,更适用于氢原子钟短期(τ≤5 d)稳定度的测量。

In order to make a comparison between the time interval counter and the dual mixer time difference measurement system used for time keeping, the measurement results （Rate, RMS, precision and stability of frequency） obtained with the two different measurement devices, the time interval counter SR-620 and the multichannel phase comparator PCOMP, for the same group of atomic clocks in the standard time and frequency laboratory of NTSC （the national time service center of the Chinese academy of sciences） are analyzed. The main conclusion drawn from the analyses is that the comparison precision for the dual mixer time difference measurement is better than that for the time interval counter, and the dual mixer time difference system is more suitable to the measurement of short-term （τ≤5d） stability for hydrogen atomic clocks.