Fractional frequency ratio difference time series data sets (Optical frequency comb comparison)

The second column is a fractional frequency ratio difference. These are pre-processed measurement data. The pre-processing steps consist in processing beat frequency data, which where measured using K&K FXE80 dead-time-free frequency counters in \Lambda-mode with a report time of 1s.

In a first step, invalid data are identified and marked as invalid (e.g. if cycle slips occurred in phase-locked loops in the experiment). This results in gaps, i.e. the time stamps are in principle on 1s grid, but there can be periods without data longer than 1s. In the second step, several beat frequency data are processed according to equation (2) in the mentioned publication, yielding the fractional frequency ratio difference y_{DUT-ref} between the reference and DUT frequency transfer system.

Statistical properties, like e.g. the mean value, linear drift, power spectral density, Allan deviation, modified Allan deviation, etc. can be derived from the y_{DUT-ref} time series.