The absolute frequency of the $^{ 87}{ \rm Sr}$ lattice clock transition was evaluated with an uncertainty of $1.1\times 10^{ -15}$ using a frequency link to the international atomic time (TAI). The frequency uncertainty of a hydrogen maser used as a transfer oscillator was reduced by homogeneously distributed intermittent measurement over a five-day grid of TAI. Three sets of four or five days measurements as well as systematic uncertainty of the clock at $8.6\times 10^{ -17}$ have resulted in an absolute frequency of $^{ 87}{ \rm Sr}\ { }^1S_0 - { }^3P_0$ clock transition to be 429 228 004 229 872.85 (47) Hz.
Categories: physics.atom-ph physics.optics quant-ph