Dear time-nuts In case of interest, you may check our fresh conference preprints from IEEE--UFFC International Frequency Control Symposium -- European Frequency and Time Forum 2013, just finished: 1. Clock Composition by Wiener Filtering Illustrated on Two Atomic Clocks - about clock ensembling using estimator - advantages over PLL&FLL (+ case study) - much simpler in LTI case over currently used Kalman filters 2. Programmable Delay Controller Allowing Frequency Synthesis and Arbitrary Binary Waveform Generation - controllable delay line within FPGA fabric - likely novel enhancement, possibly allowing to replace DDSes etc. - still unsure, if it may actually improve frequency control circuits and become widespread, or remain a curiosity only... You can read papers and view poster/presentation at: http://rtime.felk.cvut.cz/~pecam1/eftf/ Best regards, Marek P.s> After proceedings will be published, I'll replace by IEEE marked versions, in accordance with Copyright agreement.