THE FCDP and the ACES Clock Signal
The Frequency Comparison and Distribution Package (FCDP), developed by EADS under ESA responsibility is the node of the atomic clock ensemble. PHARAO and SHM 100 MHz clock signals are delivered to the FCDP and compared in both frequency and phase. The direct comparison of the two clocks has two purposes which are to drive the short term servo loop for phase locking PHARAO local oscillator onto the SHM and to evaluate the on-board clock stability. Finally, the FCDP distributes the ACES clock signal to the MWL.