Comparing Master-Slave Topologies for Time Signal Distribution

Since phase-locked loops (PLLs) were conceived by Bellescize in 1932, their presence has become almost mandatory in any telecommunication device or network, being the essential element to recover frequency and phase information. As the technology developed, PLL appeared in several applications, such as, dense communication networks; smart grides; electronic instrumentation; computational clusters; and integrated circuits. In all of these practical cases, isolated or networked PLLs are responsible for correct recovering of the time basis, synchronizing the processes. According to the application needs, different clock distribution strategies were developed, with the master-slave being the simplest and most used choice. Considering that the master clock is obtained from a stable periodic oscillator, two topologies are studied: one-way, not considering clock feedback; and two-way master-slave, with the slave nodes providing clock feedback to the master. Here, these two cases are studied by using simulation strategies, presenting results about the clock signal recovery process in the presence of disturbances, indicating that master-slave clock distribution networks can be useful for networks with few nodes and stable master oscillator with the one-way topology presenting better results than the two-way arrangement.