Femtosecond precision via RF Backplane in MTCA crates

Modern accelerator control systems based on MTCA.4 platform require femtosecond synchronization of RTM cards containing analog front-end electronics for high-speed digital signal processing AMC cards. The main challenge in such system was to realize distribution of few tens of high-quality RF signals to and between RTM cards with high reliability. Usage of coaxial cables with RF connectors in relatively small area of RTM front panels lead to difficulties with fitting all cables and to ground loop problems. Cable based distribution significantly affected system reliability and was prone to errors during installation. A concept of RF Backplane was developed for MTCA.4 system to distribute high-precision clock, and RF phase reference signals together with managed high analog quality power supply to RTM cards. It also allows for world's first solution with hot-swap on RF signals. In this paper RF Backplane conception is described together with study on performance limits.