MULTI-CHANNEL FREQUENCY CALIBRATION SYSTEM BASED ON DUAL MIXER TIME DIFFERENCE TECHNIQUE

摘要

In order to provide calibration service to frequency standard more efficiently, a new multi-channel frequency calibration system has been established in National Institute of Metrology (NIM), China. It will replace the old system which has worked for more than 15 years. In this paper, we mainly introduce the basic structure and principle of the new frequency calibration system. Measurement uncertainty of the system is less than 3×10~(-13)(Sample time is 1 second) due to Dual Mixer Time Difference (DMTD) technique. In addition, long-term stability and short-term stability of frequency standard can be measured simultaneously using the new system. The measurement results show that the new system for frequency calibration is successful and effective.