A Master Clock (based on precision Quartz Crystal Oscillators or Rubidium Vapor Atomic Oscillators) is intended to be used where timing is critical, but the host device may need to perform autonomously. For example, a satellite requires an internal clock, which is synchronized with clocks on earth. Since the satellite can be out of touch with ground stations from time-to-time and when contact is re-established, both the internal and earth clocks must be in perfect synchronization to maintain communication.

	ACTS Frequency Generator FE-5150A 5 MHz to 6.8 MHz, Fully redundant, includes DC/DC Converter
	Syracuse 1, 2 Triple Redundant Master Quartz Clock and Distribution Assembly with 60 Isolated Outputs
	Cesium Beam Atomic Frequency Standard
	Eutelsat II Local Oscillator
	Advanced EHF Space System • Triple Redundant Rubidium Atomic Standards • Triple Redundant Precision Quartz Oscillators • Double Redundant Multiple Frequency RF Synthsizers • Triple Redundant DC/DC Converters • Triple Redundant Mil-Std-1553B Serial Interface