Some results and an estimate of the current uncertainty of the PTBs reconstructed primary clock CS1

The paper briefly describes the reconstructed primary clock CS1 of the Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany, the estimation of its type B standard uncertainty, and some results obtained during the first year of routine operation. The present estimate of the CS1 type B standard uncertainty is 7/spl times/10/sup -15/ (I/spl sigma/).