302 - Cycle XACT

The project aims to develop a versatile instrument (Cycle XACT: eXact Atomic Clock Tester)) for testing and comparing ultra-stable atomic microwave and optical clocks. By combining an 8-channel phasemeter and an 8channel Time Interval Counter (TIC) within a single platform, Cycle XACT intends to enable simultaneous phase, frequency and time interval measurements with femtosecond-level phase sensitivity and picosecond-level time interval measurement capability. 

The instrument is being developed to address the growing need for advanced timing validation equipment for GNSS infrastructures, UTC laboratories, national metrology institutes, quantum networks and future optical clock applications. Building on Cycle's heritage in ESA's Frequency and Timing Distribution Systems for the ESTRACK ground station network, the project aims to transform existing technologies into a flexible, standalone product supporting clock characterization, synchronization diagnostics and the validation of next-generation timing systems, thereby strengthening European capabilities in Positioning, Navigation and Timing (PNT).