Abstract: Apparatus and method for producing a composite clock signal with optimized stability characteristics from individual clocks which have different stabilities or variances. The composite clock signal includes weighted individual clock signals. In a first (PPN) case, an optimum composite clock is a scale-factor-weighted linear combination of clock signals. In another (non-PPN) case, the optimum stable composite clock is the output of a linear filter of the input clocks signals. Both the phases and frequencies of the individual clocks over time are estimated.

Abstract: An apparatus and method are disclosed or producing a network of composite clocks with optimized stability characteristics from individual clocks that are part of a network wherein not all clocks are in communication with each other. By communicating information among the clocks in the network, each clock can construct its best estimate of composite time based upon all clocks in the network. The clocks that do not directly communicate with a specific clock are partitioned into disjoint groups for which the interclock measurements are compressed by a neighboring clock into a single composite clock. Each clock measures its time against the raw time of the clocks with which it is in direct communication and also inputs to its filter correction data for each of these composite clocks. The composite clock algorithm employed is dependent on the stability characteristics of the clocks in the network.