Time and Frequency Transfer via Microwave Link

A two-way microwave link between the Naval Research Laboratory and the Naval Observatory has been established to transfer both time and frequency information with high accuracy. Time and frequency information are transmitted simultaneously by algebraically adding together a precision 1-MHz signal and 1 pps, thus providing continuous phase information for frequency comparison and epoch time by the pulse. Phase resolution is better than 10 ns and determination of epoch time better than 0.1 ??s. Seven precision standards have been intercompared via the microwave link. Continuous phase recording since September 1969 has shown no diumal dependence and very little effect due to seasonal and temperature changes. A second microwave link has been established between the Naval Observatory and the Naval Research Laboratory's satellite research communications terminal in Waldorf, Md.