There are three main source of accurate atomic clock time in Europe: DCF77, MSF-60 and GPS.
DCF-77 is a long wave transmitted radio signal. The 77.5kHz signal is generated from atomic clocks that are linked with the German master clocks in Braunschweig. The transmitter is located in Frankfurt, Germany. The 50kW transmitted signal can be received throughout most of Europe at a distance of up to 2000Km.
The atomic clock time signal is transmitted as a amplitude modulated coded signal. The time code is encoded in pulses of the carrier. Each pulse is a data bit encoded at one pulse per second. At the end of each minute the pulses can be decoded into a time and date stamp. The encoded time is retransmitted repeatedly each minute.
TimeTools MLS Radio Atomic Clock