A Very Low Frequency (VLF) Synchronizing System
C. H. Looney · Proceedings of the IRE · 1961
A receiving system for the use of standard-frequency Navy and NBS VLF transmissions to phase-control a local frequency standard has been designed, built, and tested. Frequency synchronization accuracies of better than one part in 10,000,000,000 are practical, and the electronic instrumentation of the receiving system is not complex. Techniques for time synchronization to similar accuracies are not yet available; however, a time standard may be maintained in time accuracy to within 10 μsec once a synchronization is performed.