Satellite master oscillators

Quartz oscillators which serve as the time and frequency references on satellite missions are called upon to meet stringent performance requirements. Recent applications call for the best possible stabilities and low noise performance while at the same time demanding features such as high resolution remote digital tuning, which can potentially compromise ultimate stability. In this paper, we present test results and a discussion of some design criteria and strategies for meeting requirements of high precision, survivability and reliability. Long term testing of Allan deviation is described, and aging rate results in the low e-11 range are presented. High resolution test methods and results for radiation sensitivity screening are discussed, with particular reference to low dose testing. Resonator sensitivities in the 1e-11 per rad range for a 4 rad/hour exposure have been observed for 4 MHz adhered electrode SC-cut resonators.