FCDP
FCDP AND ACES CLOCK SIGNAL
The Frequency Comparison and Distribution Package (FCDP), developed by EADS under ESA responsibility, is the core of the atomic clock ensemble. PHARAO and SHM 100-MHz clock signals are delivered to the FCDP and their frequency and phase compared. Direct comparison of the two clocks has two purposes: to drive the short-term servo loop for phase-locking PHARAO’s local oscillator to the SHM, and to assess onboard clock stability. Finally, the FCDP distributes the ACES clock signal to the MWL.