ITU-T G.8272 (PRTC) One-Page Summary

Title: Timing characteristics of Primary Reference Time Clocks

Summary

• Primary Reference Time Clock equipment specification

• Provides an accurate time reference into the network, using either 1pps or PTP output

• Typical implementation based on GNSS

• Jitter/wander based on PRC specification (G.811)

• Describes test strategies for evaluating the performance of PRTC implementations

Status

• Current version: 4th Edition, July 2025
• Download from: http://www.itu.int/ITU-T/recommendations/rec.aspx?rec=13769

Key Contents

Time Accuracy (clear sky)

• Class A PRTC: within 100ns of UTC
• Class B PRTC: within 40ns of UTC

Wander:

Functional Model:

Test Strategies: