Developments of rubidium frequency standards at Neuchatel Observatory

The paper describes developments of novel miniaturized rubidium frequency standards. Two variants stem from the same principal design based upon a magnetron cavity. (1) a very small industrial unit for standard commercial applications. The overall volume of this model is only 0.251 with a mass of 470 g and power consumption of 8 W. This unit is close to industrialization, (2) a rugged spaceborne oscillator designed for operation on various spacecrafts or missions. This model was developed in the framework of ESA's In-Orbit Technology Demonstration Program. Two units, outcome from the present development, will constitute the main time reference for the Russian RADIOASTRON I space VLBI satellite. For this particular application the short time stability and temperature sensitivity are very important. The measured short time stability is /spl sigma/y=4/spl middot/10/sup -12//spl middot//spl tau/-/sup 1/2/ with 1.6/spl middot/10/sup -10/ temperature sensitivity over the whole operating range -20/spl deg/C to 65/spl deg/C.<
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