NIM frequency stability measurement system

Abstract

Advances in the frequency stability measurement at National Institute of Metrology (NIM) are presented. The performance of the automated measurement system is described. The measuring uncertainty is discussed in detail. It is pointed out that the noise floor is better than -176 dBc/Hz for the frequency-domain system, and is nearly sigma /sub y/( tau ) approximately=5*10/sup -14/ tau ( tau =1 ms-0.1 s), 1.5*10/sup -13/( tau =1 s) in the time domain (BW>or=5/ tau ). Some measuring examples at 5 MHz are given. >