Clock synchronization system for on-board regenerative satellite communication

A clock synchronization method is one of the most important techniques to construct a multibeam regenerative TDMA system. This paper proposes a digital loop filter and a digitally controlled oscillator in order to satisfy the requirements of this method. A prototype clock synchronization system with the digital loop filter and digitally controlled oscillator which operates at 35 MHz was trially manufactured. Experiments were carried out and the following performance were confirmed: (1) phase jitter is less than the required value of about + or - 3 degrees; (2) settling time is a few milliseconds.