ITU-T G.8273.2 (T-BC and T-TSC) One-Page Summary
- Gordon Muir (Deactivated)
- Stefano Ruffini
Title: Timing characteristics of Telecom Boundary Clocks (T-BC) and Telecom Slave Clocks (T-TSC)
Summary
Clock specification for T-BC (boundary clock) and T-TSC (time slave clock) for full timing support architecture, including noise tolerance, noise generation, noise transfer, phase transients
Four clock types defined, classes A to D:
Class A intended for short chains (up to 10 clocks), to meet ±1.5µs overall requirement
Class B intended for long chains (up to 20 clocks) , to meet ±1.5µs overall requirement
Class C intended for long chains (up to 20 clocks), suitable for fronthaul applications
Class D intended for long chains, delivered over new interface types (e.g. FlexE, FlexO) with special provision for low-noise timing transmission
Status
Current version: 2nd. Edition, October 2020, plus Amd. 1, Feb 2022 and Amd. 2, Nov 2022
Download from: http://www.itu.int/ITU-T/recommendations/rec.aspx?rec=13109
Key Contents
Noise Generation:
| Parameter | Conditions | Class A | Class B | Class C | Class D |
|---|---|---|---|---|---|
| Max |TE| | Unfiltered, 1000s | 100ns | 70ns | 30ns | - |
| Max|TEL| | 0.1Hz low-pass filter,1000s | - | - | - | 5ns |
| cTE | Averaged over 1000s | 50ns | 20ns | 10ns | - |
| dTEL MTIE | 0.1Hz low-pass filter, Const. temp, 1000s | 40ns | 40ns | 10ns | - |
| 0.1Hz low-pass filter, Var. temp, 10000s | 40ns | 40ns | 10ns | - | |
| dTEL TDEV | 0.1Hz low-pass filter, Const. temp, 1000s | 4ns | 4ns | 2ns | - |
| dTEH | 0.1Hz high-pass filter, Const. temp, 1000s | 70ns | 70ns | 30ns | - |
Transfer Function:
Simplified Functional Model:
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