A new synchronized ultra miniature rubidium oscillator

It is now possible to put a complete rubidium atomic clock together with a pulse per second generation fully synchronized to reference signal such as GPS/PPS time signal or any other signal extracted from telecom ISDN frame synchronization pulse inside a volume of 90 cm/sup 3/. This new rubidium oscillator is disciplined to a PPS (pulse per second) reference signal. The relative stability of the incoming PPS Ref is continuously analyzed and the loop time constant adapted. This way, no extra noise from the tracking loop is added. Therefore, it is possible to directly connect the PPS Ref of a GPS engine to this time machine without any analysis and software tuning. This leads to an ultra-stable time and frequency machine usable for many applications such as: synchronization of telecommunications systems (SDH, SONET, CDMA), military communications, navigation and instrumentation. The tracking software also takes into account the thermal fluctuations and avoid a too big loop time constant in unstable environment.