Kumagai, M.Ito, H.Hosokawa, M.Santarelli, G.Locke, C.R.Hartnett, J.G.2014-11-042014-11-042008Proceedings, 2008 IEEE International Frequency Control Symposium, FCS, 2008, pp.576-58097814244179571075-6787http://hdl.handle.net/2440/86918We have developed a 1 GHz synthesis chain based on a cryogenic sapphire oscillator. The 11.2005 GHz output of the CSO is down-converted for laboratory distribution. The frequency stability of the down-converter itself is 2times10⁻¹⁵ at an averaging time of 1 second. The long-term drift of the CSO is suppressed by referencing it to a hydrogen maser linked to Japan Standard Time. An application of this highly stable reference is absolute frequency measurement of an ultra-narrow clock laser for the optical frequency standard performed using a frequency comb, in which the repetition rate is stabilized by the CSO signal.en©2008 IEEEConference paper003001069910.1109/FREQ.2008.46230652-s2.0-55649115107136637