Timing Devices

Abstract

There are a number of timing devices that are used in various scenarios to achieve precise synchronization, some as standalone device while others are integrated as subsystem to enable host circuitry. This timing devices integrate GNSS-based PRTC and may include quality oscillators. A GRU (GNSS Receiver Unit) is a good example of typical PRTC which comes in different forms as standalone external device, a timing module and disciplined clock or better known as GNSSDO (GNSS Disciplined Oscillator). The GNSSDO includes high-quality oscillator that are continuously corrected to provide stable clock and failover for more than 24 h in case of GNSS outage. The GRUs can also be integrated within a GNSS antenna to save space and cost. Grandmaster, boundary clock, and ePRTC are specially designed for packet network; these devices include GRU as an embedded function with packet engine and protocol stack to distribute time across the network. While boundary clock extends the reach of grandmaster precise clock services to the edge, ePRTC acts as central device serving core stable clock to various network segments. Typically, an ePRTC integrates a very high-quality oscillator that meets atomic frequency standard. The device is capable of providing up to 14 days of holdover in case of GNSS outage.